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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to and the benefit of Korean Patent Application No. 10-2008-0023946, filed on Mar. 14, 2008, the entire contents of which are incorporated herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a gear train of an automatic transmission for a vehicle that realizes a plurality of forward speeds, and in particular, seven forward speeds and reverse.
[0004] 2. Description of Related Art
[0005] A conventional shift mechanism of an automatic transmission utilizes a combination of a plurality of planetary gear sets. A gear train of such an automatic transmission changes rotating speed and torque received from a torque converter of the automatic transmission and transmits the changed torque to an output shaft.
[0006] It is well known that when a transmission realizes a greater number of shift speeds, speed ratios of the transmission can be more optimally designed and therefore a vehicle can have better fuel mileage and better performance. For that reason, an automatic transmission that enables more shift speeds is under constant investigation.
[0007] In addition, with the same number of speeds, features of a gear train such as durability, efficiency in power transmission, and size depend in part on the layout of combined planetary gear sets. Therefore, designs for a combining structure of a gear train are also under constant investigation.
[0008] A manual transmission that has too many speeds causes inconvenience of excessively frequent shifting operations to a driver. Therefore, the positive features of more shift-speeds are generally more important for automatic transmissions because an automatic transmission automatically controls shifting operations basically with reduced manual operation by a driver.
[0009] In addition to various developments regarding four and five speed gear trains, six-speed automatic transmissions have recently been developed.
[0010] The above information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
BRIEF SUMMARY OF THE INVENTION
[0011] Various aspects of the present invention are directed to providing a gear train of an automatic transmission for a vehicle that realizes, meaning obtains or achieves, seven forward speeds. A gear train of an automatic transmission for a vehicle according to various aspects of the present invention includes a first planetary gear set being a simple planetary gear set provided with three rotational members, wherein a first rotational member is substantially always operated as a fixed member, a second rotational member forms a first intermediate output pathway where a reduced rotational speed is output, and a third rotational member forms an input pathway that is directly connected with an input shaft. A second planetary gear set may be combined with first and second simple planetary gear sets that have three rotational members respectively. The second planetary gear set may realize fourth, fifth, sixth, and seventh rotational members, wherein the fourth rotational member, which is realized with one rotational member, forms a first intermediate input path by being directly connected with the second rotational member, the fifth rotational member, which is realized with one rotational member, is operated as an output element by being connected with an output shaft, the sixth rotational member, which is realized with two rotational members directly connected with each other, forms a first variable input path by being variably connected with the input shaft, and is selectively operated as a fixed element by being connected with a transmission housing, the seventh rotational member, which is realized with two rotational members variably connected or separated from each other, forms a second intermediate input path by being variably connected with the second rotational member, forms a second variable input path by being variably connected with the input shaft, and is operated as a variable fixed element by being variably connected with the transmission housing. A plurality of friction members including clutches and brakes selectively connect the rotational members with one of the other rotational members, the transmission housing, or the input shaft.
[0012] The plurality of friction members may include a first clutch disposed for selectively integrally connecting the seventh rotational member; a second clutch disposed in the second intermediate input path; a third clutch disposed in the first variable input path; a fourth clutch disposed in the second variable input path; a one-way clutch and a first brake disposed in parallel between the sixth rotational member and the transmission housing; and a second brake disposed between the seventh rotational member and the transmission housing.
[0013] The first planetary gear set may be a single pinion planetary gear set, wherein the first rotational member is a first sun gear, the second rotational member is a first planet carrier, and the third second rotational member is a first ring gear; and the second planetary gear set may be a combination of a first simple planetary gear set, which is a single pinion planetary gear set, and a second simple planetary gear set, which is a double pinion planetary gear set, wherein the fourth rotational member is a third sun gear of the second simple planetary gear set, the fifth rotational member is a second ring gear of the first simple planetary gear set, the sixth rotational member is a second planet carrier of the first simple planetary gear set and a third ring gear of the second simple planetary gear set, and the seventh rotational member is a second sun gear of the first simple planetary gear set and a third planet carrier of the second simple planetary gear set.
[0014] The first clutch and the one-way clutch may be operated in the first forward speed. The first clutch and the second brake may be operated in the second forward speed. The first clutch and the second clutch may be operated in the third forward speed. The first clutch and the fourth clutch may be operated in the fourth forward speed. The first clutch and the third clutch may be operated in the fifth forward speed. The second clutch and the third clutch may be operated in the sixth forward speed. The third clutch and the second brake may be operated in the seventh forward speed. The second clutch and the first brake may be operated in a reverse speed.
[0015] The third clutch may be disposed between the third ring gear and the input shaft, and the first brake with the one-way clutch may be disposed between the second planet carrier and the transmission housing.
[0016] The first clutch may be disposed between the second sun gear and the third planet carrier, the second clutch may be disposed between the second rotational member and the second sun gear, and the second brake may be disposed between the second clutch and the second sun gear.
[0017] The first planetary gear set may be a double pinion planetary gear set, wherein the first rotational member is a first sun gear, the second rotational member is a first ring gear, and the third rotational member is a first planet carrier. The second planetary gear set may be a combination of a first simple planetary gear set, which is a single pinion planetary gear set, and a second simple planetary gear set, which is a double pinion planetary gear set. The fourth rotational member may be a third sun gear of the second simple planetary gear set, the fifth rotational member is a second ring gear of the first simple planetary gear set, the sixth rotational member is a second planet carrier of the first simple planetary gear set and a third ring gear of the second simple planetary gear set, and the seventh rotational member is a second sun gear of the first simple planetary gear set and a third planet carrier of the second simple planetary gear set.
[0018] The first clutch and the one-way clutch may be operated in the first forward speed. The first clutch and the second brake may be operated in the second forward speed. The first clutch and the second clutch may be operated in the third forward speed. The first clutch and the fourth clutch may be operated in the fourth forward speed. The first clutch and the third clutch may be operated in the fifth forward speed. The second clutch and the third clutch may be operated in the sixth forward speed. The third clutch and the second brake may be operated in the seventh forward speed. The second clutch and the first brake may be operated in a reverse speed.
[0019] The third clutch may be disposed between the third ring gear and the input shaft, and the first brake with the one-way clutch may be disposed between the second planet carrier and the transmission housing.
[0020] The first clutch may be disposed between the second sun gear and the third planet carrier. The second clutch may be disposed between the second rotational member and the second sun gear. The second brake may be disposed between the second clutch and the second sun gear.
[0021] In various embodiments of the present invention, a gear train of an automatic transmission for a vehicle includes a first planetary gear set being a single pinion planetary gear set and including a first sun gear, a first planet carrier, and a first ring gear; a second planetary gear set that is a combination of a first simple planetary gear set, being a single pinion planetary gear set and including a second sun gear, a second planet carrier, and a second ring gear, and a second simple planetary gear set, being a double pinion planetary gear set and including a third sun gear, a third planet carrier, and a third ring gear, wherein the first ring gear is directly connected with an input shaft, the first planet carrier is directly connected with the third sun gear, the second planet carrier is directly connected with the third ring gear, and the second ring gear is directly connected with an output shaft. A first clutch may be disposed between the second sun gear and the third planet carrier. A second clutch may be disposed between the first planet carrier and the second sun gear. A third clutch may be disposed between the input shaft and the third ring gear. A fourth clutch may be disposed between the input shaft and the third planet carrier. A one-way clutch and a first brake may be disposed in parallel between the second planet carrier and a transmission housing. A second brake may be disposed between the second sun gear and the transmission housing.
[0022] In various embodiments, a gear train of an automatic transmission for a vehicle may include a first planetary gear set being a double pinion planetary gear set and including a first sun gear, a first planet carrier, and first ring gear. A second planetary gear set may be a combination of a first simple planetary gear set, which is a single pinion planetary gear set including a second sun gear, a second planet carrier and a second ring gear, and a second planetary gear set, which is a double pinion planetary gear set including a third sun gear, a third planet carrier and a third ring gear. The first planet carrier may be directly connected with an input shaft. The first ring gear may be directly connected with the third sun gear. The second planet carrier may be directly connected with the third ring gear. The second ring gear, may be directly connected with an output shaft. A first clutch may be disposed between the second sun gear and the third planet carrier. A second clutch may be disposed between the first ring gear and the second sun gear. A third clutch may be disposed between the input shaft and the third ring gear. A fourth clutch may be disposed between the input shaft and the third planet carrier. A one-way clutch and a first brake may be disposed in parallel between the second planet carrier and a transmission housing. A second brake may be disposed between the second sun gear and the transmission housing.
[0023] The gear train according to various aspects of the present invention may be formed by combining two planetary gear sets, four clutches, and two brakes to realize seven forward speeds.
[0024] The frictional elements are decentralized so that a hydraulic line may be easily constructed, and only two frictional elements are operated in each shifting so that the volume of a hydraulic pump may be reduced and hydraulic pressure control efficiency may be enhanced.
[0025] The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic diagram of an exemplary gear train according to various aspects of the present invention.
[0027] FIG. 2 is an operational chart for the exemplary gear train illustrated in FIG. 1 .
[0028] FIG. 3 is a lever diagram for the exemplary gear train illustrated in FIG. 1 .
[0029] FIG. 4 is a schematic diagram of an exemplary gear train similar to the gear train of FIG. 1 .
[0030] FIG. 5 is a lever diagram for the exemplary gear train illustrated in FIG. 4 .
DETAILED DESCRIPTION OF THE INVENTION
[0031] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
[0032] FIG. 1 is a schematic diagram of a gear train according to various embodiments of the present invention. A gear train includes first and second planetary gear sets PG 1 and PG 2 , four clutches C 1 , C 2 , C 3 , and C 4 , two brakes B 1 and B 2 , and a one-way clutch F.
[0033] The first planetary gear set PG 6 reduces a rotational speed of an input shaft IS and transmits a reduced speed to the second planetary gear set PG 2 . The second planetary gear set PG 1 receives the reduced speed from the first planetary gear set PG 1 and the rotational speed from the input shaft IS, selectively, and outputs seven forward speeds and one reverse speed through an output shaft OS.
[0034] For this purpose, the first planetary gear set PG 1 is disposed close to an engine (not shown), and the second planetary gear set PG 2 is sequentially disposed.
[0035] The input shaft IS is an input member and is a turbine shaft of a torque converter. Torque transmitted from a crankshaft of the engine is supplied to the input shaft IS through the torque converter. The output shaft OS is an output member and torque of the output shaft OS is transmitted to a differential apparatus through an output gear (not shown) and drives a driving wheel.
[0036] The first planetary gear set PG 1 is a simple and single planetary gear set and includes a first rotational member N 1 of a first sun gear S 1 , a second rotational member N 2 of a first planet carrier PC 1 , and a third rotational member N 3 of a first ring gear R 1 .
[0037] The first rotational member (N 1 ; the first sun gear S 1 ) is always operated as a fixed element by being directly connected with a transmission housing H.
[0038] The second rotational member (N 2 ; the first planet carrier PC 1 ) forms a first intermediate output path MOP 1 where reduced rotational speed is output.
[0039] The third rotational member (N 3 ; the first ring gear R 1 ) is directly connected to the input shaft IS so as to form an input pathway IP.
[0040] The second planetary gear set PG 2 is formed by combining first and second simple planetary gear sets SPG 1 and SPG 2 and includes fourth, fifth, sixth, and seventh rotational members N 4 , N 5 , N 6 , and N 7 . In various embodiments of the present invention, the first simple planetary gear set SPG 1 is a single pinion planetary gear set and the second simple planetary gear set SPG 2 is a double pinion planetary gear set.
[0041] The second carrier PC 2 is directly connected with the third ring gear R 3 , and the second sun gear S 2 and the third planet carrier PC 3 are variably connected by the first clutch C 1 .
[0042] Thus, the fourth rotational member N 4 is the third sun gear S 3 , the fifth rotational member N 5 is the second ring gear R 2 , the sixth rotational member N 6 is the second planet carrier PC 2 and the third ring gear R 3 , and the seventh rotational member N 7 is the second sun gear S 2 and the third planet carrier PC 3 .
[0043] The fourth rotational member (N 4 ; the third sun gear S 3 ) is directly connected with the second rotational member N 2 and forms a first intermediate input path MIP 1 for receiving the reduced speed from the first planetary gear set PG 1 .
[0044] The fifth rotational member (N 5 ; the second ring gear R 2 ) is directly connected with the output shaft OS and forms an output path OP.
[0045] The sixth rotational member (N 6 ; the second planet carrier PC 2 and the third ring gear R 3 ) is variably connected with the input shaft IS by the third clutch C 3 . The sixth rotational member forms a first variable input path VIP 1 . The sixth rotational member is also selectively operated as a input element. Further, the sixth rotational member N 6 is variably connected with the transmission housing H by the first brake B 1 and the one-way clutch F and is selectively operated as a fixed element.
[0046] The seventh rotational member (N 7 ; the second sun gear S 2 and the third planet carrier PC 3 ) is variably connected with the first planetary gear set PG 1 by interposing the second clutch C 2 and forms a second intermediate input path MIP 2 . Also, the seventh rotational member N 7 is variably connected with the input shaft IS by clutch C 4 , forms a second variable input path VIP 2 , and is selectively operated as an input element. Further, the seventh rotational member N 7 is variably connected with the transmission housing H by interposing the second brake B 2 so as to be selectively operated as a fixed element.
[0047] The third clutch C 3 of the sixth rotational member N 6 is disposed between the third ring gear R 3 and the input shaft IS, and the first brake B 1 in parallel with the one way clutch F is disposed between the second planet carrier PC 2 and the transmission housing H.
[0048] The first clutch C 1 is disposed between the second sun gear S 2 and the third planet carrier PC 3 , the second clutch C 2 is disposed between the second rotational member N 2 and the second sun gear S 2 , the fourth clutch C 4 is disposed between the third planet carrier PC 3 and the input shaft IS, and the second brake B 2 is disposed between the second clutch C 2 and the second sun gear S 2 .
[0049] The first, second, third, and fourth clutches C 1 , C 2 , C 3 , and C 4 and the first and second brakes B 1 and B 2 may be enabled as a multi-plate hydraulic pressure friction device that is frictionally engaged by hydraulic pressure.
[0050] The first clutch C 1 is disposed between the first and second planetary gear sets PG 1 and PG 2 . The first and second brakes B 1 and B 2 and the one-way clutch F may be disposed outside of the first clutch C 1 .
[0051] The second clutch C 2 is disposed in front of the first planetary gear set PG 1 , and the third and fourth clutches C 3 and C 4 are disposed behind the second planetary gear set PG 2 , so that a decentralized disposition may be achieved.
[0052] The decentralized disposition may maintain a stable mass center and allow hydraulic lines to be easily constructed for supplying hydraulic pressure to the friction members.
[0053] FIG. 2 is an operational chart for a gear train according to various embodiments of the present invention, and as shown in FIG. 2 , the gear train illustrated in FIG. 1 may shift by operation of two friction members.
[0054] That is, the first clutch C 1 and the one-way clutch F are operated in the first forward speed, the first clutch C 1 and the second brake B 2 are operated in the second forward speed, and the first clutch C 1 and the second clutch C 2 are operated in the third forward speed. The first clutch C 1 and the fourth clutch C 4 are operated in the fourth forward speed, the first clutch C 1 and the third clutch C 3 are operated in the fifth forward speed, and the second clutch C 2 and the third clutch C 3 are operated in the sixth forward speed. The third clutch C 3 and the second brake B 2 are operated in the seventh forward speed, and the second clutch C 2 and the first brake B 1 are operated in a reverse speed. One will appreciate from the foregoing that the clutch and gear combinations may be modified in accordance with the present invention to provide a plurality of forward speeds.
[0055] FIG. 3 is a lever diagram of a gear train according to various embodiments of the present invention. In FIG. 3 , a lower horizontal line represents “0” rotational speed, and an upper horizontal line represents “1.0” rotational speed that is the same as the rotational speed of the input shaft IS.
[0056] Three vertical lines of the first planetary gear set PG 1 respectively represent the first rotational member N 1 (the first sun gear S 1 ), the second rotational member N 2 (the first planet carrier PC 1 ), and the third rotational member N 3 (the first ring gear R 1 ) sequentially from the left in the drawing, and a distance between them is determined according to a gear ratio (teeth number of sun gear/teeth number of ring gear) of the first simple planetary gear set SPG 1 .
[0057] Four vertical lines of the second planetary gear set PG 2 respectively represent the fourth rotational member N 4 (the third sun gear S 3 ), the fifth rotational member N 5 (the second ring gear R 2 ), the sixth rotational member N 6 (the second planet carrier PC 2 and the third ring gear R 3 ), and the seventh rotational member N 7 (the second sun gear S 2 and the third planet carrier PC 3 ) sequentially from the left in the drawing, and a distance between them is determined according to a gear ratio (teeth number of sun gear/teeth number of ring gear) of the first and second simple planetary gear sets SPG 1 and SGP 2 . The lever diagram is well known to a person of ordinary skill in the art, and detailed descriptions will be accordingly omitted.
[0058] Hereinafter, shifting processes in the gear train according to an exemplary embodiment of the present invention will be described in detail.
[0059] First Forward Speed
[0060] As shown in FIG. 2 , the first clutch C 1 and the one-way clutch F are operated at the first forward speed D 1 .
[0061] In this case, as shown in FIG. 3 , in a state that the input rotational speed is transmitted to the third rotational member N 3 of the first planetary gear set PG 1 , the first rotational member N 1 is operated as the fixed member. Thus, the reduced rotational speed is generated at the second rotational member N 2 .
[0062] The reduced rotational speed of the second rotational member N 2 is transmitted to the fourth rotational member N 4 that is directly connected with the second rotational member N 2 .
[0063] In a state in which the reduced rotational speed is transmitted to the fourth rotational member N 4 of the second planetary gear set PG 2 , the sixth rotational member N 6 is operated as the fixed member by operation of the one-way clutch F. Therefore, a first shift line SP 1 connecting the fourth rotational member N 4 with the sixth rotational member N 6 is formed and the first forward speed D 1 is output to the fifth rotational member N 5 , which is the output member.
[0064] Second Forward Speed
[0065] In a state of the first forward speed D 1 , the second brake B 2 is operated to achieve the second forward speed D 2 .
[0066] In a state in which the reduced rotational speed is transmitted to the fourth rotational member N 4 of the second planetary gear set PG 2 , the seventh rotational member N 7 is operated as the fixed member by an operation of the second brake B 2 . Therefore, a second shift line SP 2 connecting the fourth rotational member N 4 and the seventh rotational member N 7 is formed and the second forward speed D 2 is output to the fifth rotational member N 5 , which is the output member.
[0067] Third Forward Speed
[0068] In a state of the second forward speed D 2 , the second brake B 2 is released and the second clutch C 2 is operated to achieve the third forward speed D 3 .
[0069] The reduced rotation speed of the second rotational member N 2 is transmitted to the fourth rotational member N 4 and to the seventh rotational member N 7 by an operation of the second clutch C 2 and the first clutch C 1 . Thus, the second planetary gear set PG 2 becomes in a lock state and a third shift line SP 3 connecting the fourth rotational member N 4 and the seventh rotational member N 7 is formed, and the third forward speed D 3 is output to the fifth rotational member N 5 , which is the output member.
[0070] Fourth Forward Speed
[0071] In a state of the third forward speed D 3 , the second clutch C 2 is released and the fourth clutch C 4 is operated to achieve the fourth forward speed D 4 .
[0072] The reduced rotation speed of the second rotational member N 2 is transmitted to the fourth rotational member N 4 , and the rotation of the input shaft IS is transmitted to the seventh rotational member N 7 by an operation of the fourth clutch C 4 . Thus, a fourth shift line SP 4 connecting the fourth rotational member N 4 and the seventh rotational member N 7 is formed, and the fourth forward speed D 4 is output to the fifth rotational member N 5 , which is the output member.
[0073] Fifth Forward Speed
[0074] In a state of the fourth forward speed D 4 , the fourth clutch C 4 is released and the third clutch C 3 is operated to achieve the fifth forward speed D 5 .
[0075] The reduced rotation speed of the second rotational member N 2 is transmitted to the fourth rotational member N 4 , and the rotation of the input shaft IS is transmitted to the sixth rotational member N 6 by an operation of the third clutch C 3 . Therefore, a fifth shift line SP 5 connecting the fourth rotational member N 4 and the sixth rotational member N 6 is formed, and the fifth forward speed D 5 is output to the fifth rotational member N 5 , which is the output member.
[0076] Sixth Forward Speed
[0077] In a state of the fifth forward speed D 5 , the first clutch C 1 is released and the second clutch C 2 is operated to achieve the sixth forward speed D 6 .
[0078] The reduced rotation speed of the second rotational member N 2 is transmitted to the seventh rotational member N 7 by an operation of the second clutch C 2 , and the rotation of the input shaft IS is transmitted to the sixth rotational member N 6 by an operation of the third clutch C 3 . Thus, a sixth shift line SP 6 connecting the sixth rotational member N 6 and the seventh rotational member N 7 is formed, and the sixth forward speed D 6 is output to the fifth rotational member N 5 , which is the output member.
[0079] Seventh Forward Speed
[0080] In a state of the sixth forward speed D 6 , the second clutch C 2 is released and the second brake B 2 is operated to achieve the seventh forward speed D 7 .
[0081] The rotation of the input shaft IS is transmitted to the sixth rotational member N 6 by the operation of third clutch C 3 , and the seventh rotational member N 7 is operated as the fixed member by the operation of the second brake B 2 . Therefore, a seventh shift line SP 7 connecting the sixth rotational member N 6 and the seventh rotational member N 7 is formed, and the seventh forward speed D 7 is output to the fifth rotational member N 5 , which is the output member.
[0082] Reverse Speed
[0083] The first clutch C 2 and the first brake B 1 are operated in the reverse speed RS.
[0084] The rotation speed of the input shaft IS is transmitted to the third rotational member N 3 of the first planetary gear set PG 1 , and the first rotational member N 1 is operated as the fixed member. Thus, reduced rotation is output through the second rotational member N 2 .
[0085] The reduced rotation of the second rotational member N 2 is transmitted to the seventh rotational member N 7 by the operation of the second clutch C 2 and the sixth rotational member N 6 is operated as a fixed element by the operation of the first brake B 1 . Thus, a reverse shift line SR is formed, and the reverse speed RS is output to the fifth rotational member N 5 , which is the output member.
[0086] In the first forward speed, as shown in FIG. 3 , in the state that the first clutch C 1 is operated, the fourth rotational member N 4 is operated as an input element and the sixth rotational member N 6 is operated as a fixed element by the operation of the one-way clutch F, and thus, shifting is performed.
[0087] In a state of the first forward speed D 1 , the second brake B 2 is operated so that the seventh rotational member N 7 is operated as a fixed element, and thus, shifting is performed to achieve the second forward speed D 2 .
[0088] In a state of the second forward speed D 2 , the second brake B 2 is released and the second clutch C 2 is operated to achieve the third forward speed D 3 . Thus, the reduced rotation of the first planetary gear set PG 1 is transmitted to the fourth rotational member N 4 and the seventh rotational member N 7 , and thus, the second planetary gear set PG 2 becomes or moves to the lock state.
[0089] In a state of the third forward speed D 3 , the second clutch C 2 is released and the fourth clutch C 4 is operated to achieve the fourth forward speed D 4 . Thus, different rotation speeds are transmitted to the fourth rotational member N 4 and the seventh rotational member N 7 , and shifting is performed to achieve the fourth forward speed D 4 .
[0090] In a state of the fourth forward speed D 4 , the second clutch C 2 is released and the third clutch C 3 is operated to achieve the fifth forward speed D 5 . Thus, different rotation speeds are transmitted to the fourth rotational member N 4 and the sixth rotational member N 6 , and shifting is performed to achieve the fifth forward speed D 5 .
[0091] In a state of the fifth forward speed D 5 , the first clutch C 1 is released and the second clutch C 2 is operated to achieve the sixth forward speed D 6 . Thus, a connection of the second sun gear S 2 and the third planet carrier PC 3 is released and different rotation speeds are transmitted to the sixth rotational member N 6 and the seventh rotational member N 7 , and shifting is performed to achieve the sixth forward speed D 6 .
[0092] In a state of the sixth forward speed D 6 , the second clutch C 2 is released and the second brake B 2 is operated to achieve the seventh forward speed D 7 . Thus, the seventh rotational member N 7 is operated as a fixed, or substantially fixed, element, and shifting is performed to achieve the seventh forward speed D 7 .
[0093] The second clutch C 2 and the first brake B 1 are operated in the reverse speed RS. A reduced rotation speed is transmitted to the seventh rotational member N 7 and the sixth rotational member N 6 is operated as a fixed element, and thus, shifting is performed to achieve the reverse speed.
[0094] When the first clutch C 1 is released in the sixth and seventh forward speeds D 6 and D 7 , and the reverse speed shifting are operated, a connection of the second sun gear S 2 and the third planet carrier PC 3 is released. Two rotational members receive rotation speed, and the second planetary gear set PG 2 becomes or moves to the unlock state so that shifting is operated.
[0095] FIG. 4 is a schematic diagram of a gear train according to various embodiments of the present invention. A scheme of the second planetary gear set PG 2 is the same as that of the above exemplary embodiments while a scheme of the first planetary gear set PG 1 is different thereto.
[0096] That is, the first planetary gear set PG 1 is a single pinion planetary gear set in the above exemplary embodiment of the present invention; however, the first planetary gear set PG 1 is a double pinion planetary gear set in the present exemplary embodiments of the present invention.
[0097] The first rotational member N 1 is the first sun gear S 1 , the second rotational member N 2 is the first ring gear R 1 , and the third rotational member N 3 is the first planet carrier PC 1 .
[0098] The second rotational member N 2 of the first ring gear R 1 forms a first intermediate output path MOP 1 , and the third rotational member N 3 of the first planet carrier PC 1 is operated as an input element.
[0099] Shifting of the gear train according to the exemplary embodiments of the present invention is the same as that of the above exemplary embodiments of the present invention.
[0100] That is, friction members are operated in each speed as shown in FIG. 2 , and the shifting operations of the exemplary embodiment remain the same as those of the above embodiments except for the second and third rotational members N 2 and N 3 , and are therefore not described in further detail.
[0101] For convenience in explanation and accurate definition in the appended claims, the terms “up” or “upper”, “down” or “lower”, “front” or “rear”, “inside”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.
[0102] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. | A gear train of an automatic transmission for a vehicle includes a first planetary gear set being a simple planetary gear set and a second planetary gear set that is formed of two combined simple planetary gear sets. The gear train combines four clutches and two brakes and realizes seven forward speeds. The gear train may enhance transmitting performance and reduce fuel consumption. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the invention:
This invention relates to a method of delivery of antiinflammatory agents, particularly 5-amino salicyclic acid (5-ASA), 4(4-ASA), and 3-amino salicylic acid (3-ASA) as well as other topically effective therapeutic agents directly to the lower gastrointestinal (G.I.) tract in patients suffering from inflammatory bowel disease. In the above context, the term "lower" means distal to the pyloric sphincter.
2. Description of the prior art
It is well known that inflammatory bowel diseases such as Crohn's disease and ulcerative colitis may be gainfully treated by topical application of 5-ASA (U.S. Pat. No. 4,496,553 and No. 4,540,685). Furthermore, lower G.I. tract ulcers are usefully treated by topical application of steroid preparations.
Access to the inflamed parts is oral or anal. Rectally administered 5-ASA (e.g. via enema in U.S. Pat. No. 4,664,256) enjoys limited systemic absorbtion and consequent good topical effectiveness. However, rectally administered 5-ASA only acts locally on the recto-sigmoidal colon so that more proximal inflammation cannot be treated in this manner. Oral delivery of anti-ulceric steroids and 5-ASA to sites of inflammation located above the transverse colon, and particularly to the proximal small bowel, is more complex and successful delivery with subsequent therapeutic benefit depends on several factors. For instance, gastric emptying time varies from one individual to another and in the same individual may vary according to the size of (orally taken) particles (or tablets) and according to whether the patient is in a fasting or non-fasting state. Furthermore, dwell time in the ileum is also variable and indeed previously surgically treated patients may have a shortened small bowel. Likewise, variations in colonic bacterial flora are possible and indeed certain during antibiotic therapy.
However, the primary difficulty in accurate targeting of orally administered, topically acting steroids and 5-ASA is stomach acidity which destroys such preparations.
In the case of 5-ASA, attempts to overcome this acidity problem have included use of the prodrug sulfasalazine (SAS) which resists stomach acidity to yield free 5-ASA and sulfapyridine via enzymatic cleavage in the large bowel. Unfortunately sulfapyridine gives adverse side effects. Improvements on this principle are disclosed in U.S. Pat. Nos. 4,190,716, 4,298,595 and 4,663,308 although accurate targeting is still limited by the variability of the conditions required for bacterial cleavage.
There exist also enterically coated 5-ASA tablets which protect their contents from stomach acidity and which dissolve gradually to release the active ingredient (hopefully) at the desired site of action. However, variation of gut pH renders it impossible to preselect the final site of action.
Another attempted oral route is the drinking of either a suspension of 5-ASA with simultaneous ingestion of omeprazole which blocks the secretion of hydrochloric acid in the stomach or of a suspension could incorporate extremely small 5-ASA particles made gastric resistant by means of an appropriate coating.
Although the pH of the stomach and possibly that of the duodenum may be modified by the concomitant administration of H 2 antagonists or other drugs (like omeprazole), little is known about pH variations in the small and large bowel of patients with inflammatory bowel disease.
As a result it is impossible to predict the exact site of action of any orally taken pH profile-dependent 5-ASA, steroid formulations or other topically active agents since most depend on constant pH profiles not found in the human system.
It is therefore desirable to provide a method of delivering 5-ASA and other topically active agents to an inflamed site in the lower GI tract whereby the active agent is brought into direct, topical contact with inflamed parts of the tract while avoiding prior degradation in the stomach.
To achieve this, the present invention makes use of an enteric feeding tube. Such feeding tubes are in use primarily for providing alimentation to the stomach or to the jejunum via an abdominal incision (see "Enteral Feeding Products"--a brochure dated July 1987 of Ross Laboratories of Columbus, Ohio, U.S.A.). Nasal/oral use of such tubes for alimentary purposes is also known.
OBJECTS OF THE INVENTION
An object of the present invention is to use an enteric feeding tube for administering a medication to the G.I. tract beyond (viz. distal to) the stomach.
Another object of the invention is to provide a means of accurately targeting the site and rate of delivery of such medications to the desired inflamed areas.
A further object of the invention is to avoid use of prodrugs having adverse side effects.
Another object of the invention is to ensure topical application of anti-inflammatories, such as 5-ASA, at the site of inflammation over an appropriate amount of time (eg 4.0-12.0 hours).
Still another object of the invention is to provide a kit for carrying out the above objects.
A further, more specific object of the invention is to ensure accurate and safe delivery of topically active therapeutic agents such as 5-ASA to the duodenal, jejunal of proximal small bowel and other segments of the lower G.I. tract to allow treatment of severe Crohn's ileitis duodenitis, jejunitis as well as fulminant ulcerative colitis.
SUMMARY OF THE INVENTION
In meeting the above and other objects, the present invention provides a method of delivery of an effective amount of an anti-inflammatory agent, preferably 5-ASA, directly to a target area of the lower gastrointestinal tract in patients suffering from inflammatory bowel disease comprising:
providing a pharmaceutically acceptable suspension containing the agent to be delivered;
providing an enteric tube having first and second ends;
inserting the first end of the enteric tube upstream the target area in the lower gastrointestinal tract distal to the stomach of a patient to be treated; and
introducing said solution into the second end of said tube to expel a desired amount of said solution at a desired rate from said first end into the tract.
In this manner, the agent is brought into direct, topical contact with inflamed parts of the lower gastrointestinal tract, while avoiding prior degradation in the stomach.
The invention also provides a kit for delivery of an effective amount of an anti-inflammatory agent, again preferably 5-ASA, directly to the lower gastrointestinal tract in patients suffering from inflammatory bowel disease comprising:
a pharmaceutically acceptable solution containing the agent to be delivered;
a container for said solution; and
an enteric tube insertable into the lower gastrointestinal tract distal to the stomach of a patient to be treated.
The invention further provides for the use of an enteric tube for bringing an anti-inflammatory agent into direct, topical contact with inflamed parts of the lower gastrointestinal tract in patients suffering from inflammatory bowel disease, e.g Crohn's disease and ulcerative colitis. The objects, advantages and other features of the present invention will become more apparent upon reading of the following non-restrictive description of a preferred embodiment thereof.
DETAILED DESCRIPTION OF THE INVENTION
The kind of feeding tube useable according to the invention may be of any medically acceptable constitution. The tube may be made for example of thermoplastic elastomer, silicone rubber or polyurethane although the thermoplastic elastomer is preferred.
The tubes may be used in conjunction with a stylet or bolus of any suitable design for the provision of a solution of anti-inflammatory agent eg 5-ASA solution. Preferably the connector at the top end of the tube is adaptive to syringes and other fluid containers for their direct connection to the tube.
A preferred tube is the Flexiflo® Enteral Feeding Tube manufactured by Ross Laboratories and disclosed in the company's November 1985 brochure entitled "Enteric Feeding Tube".
Also preferred are the gastronomy kits and jejunal feeding tubes also produced by Ross Laboratories and disclosed in their earlier mentioned July 1987 brochure entitled "Enteral Feeding Products".
Another suitable tube is the so-called Frederick Miller Feeding Tube Set produced by COOK® of Bloomington, Indiana, U.S.A.
When administering a 5-ASA suspension (using the feeding tube), it is possible either to deliver free 5-ASA to the site of inflammation or to map the pH at sites of inflammation so that an oral suspension containing coated or encapsulated micro-particles having (an) appropriate (pH dependant) release profile(s) can be selected for use after initial treatment with the method or kit according to the invention.
Turning now to the solution of 5-ASA or other topically active therapeutic compounds useable in the present invention, any pharmaceutically acceptable solution or suspension may be used. This would normally be aqueous and a preferred solution is a stable suspension of substantially pure 5-aminosalicylic acid in a saturated, substantially colourless aqueous solution of 5-aminososalicylic acid of pharmaceutical grade purity having a pH of from about 3 to 5 and rendered resistant to colour formation upon storage by the dissolved presence therein, at a concentration of up to about 0.25% w/w, of an amount of bisulfite effective to stabilize the solution against colour formation and degradation eg by oxidation of the 5-aminosalicylic acid by the reaction with any trace amount of oxygen in the solution or in its container.
The way in which this preferred solution may be prepared is disclosed in U.S. patent No. 4,657,900.
The method aspect of the invention is carried out by positioning, preferably transpylorically, one end of the enteral tube at a site of inflammation in the lower G.I. tract and connecting the other end to a source of 5-ASA or other comparably topically active compound.
The tube may be introduced into the body by a number of means e.g. nasally, orally or abdominally via a naso/oral directed gastrostomy, as shown, for instance, in the abovementioned July 1987 Ross catalogue.
Positioning of the bolus end of the tube in the desired location may be achieved using a endoscope in optional conjunction with radioopacity in the tube for later X-ray confirmation of correct positioning.
A selected amount of the solution or suspension containing the active compound is expelled from the implanted bolus of the tube using an irrigation syringe, a Luer syringe or other kind of fluid injection device (e.g. plastic bottle) insertable into the end of the tube outside the body.
The effective dose depends on the extent of the disease and for adults it is usually in the range from 2 to 5.6 g per day (24 hrs). The preferred range is from 3 to 4.5 g per day.
Where the active compound is ASA, up to 80 mg/kg body weight of 5-ASA, 4-ASA or 3-ASA will be the recommended initial daily dosage subject to adjustment in accordance with the observed results of treatment. In particular the dosage for children should be adjusted following measurements of serum concentration, and of renal and hepatic functions.
The most preferred dosage is 4g of 5-ASA per day. This is preferably delivered gradually throughout the day of treatment in a volume of up to 240 ml of the suspension mentioned above. Administration over the longest period possible during the day of treatment is preferred as this minimizes absorption and maximizes topical effectiveness.
Treatment should be by instillment of 1 dosage unit (as above) per day for 2 months or longer. Two half dosage units may be instilled daily as an alternative to diminish peak absorption level of 5-ASA or N-acetyl-5-ASA.
In the following trials, the suspension given in table 1 was used in a dosage unit of 4g per day of 5-ASA per 240 ml of suspension.
TABLE 1______________________________________AMOUNT per UNITLabel Actual BATCHper 60 g % w/w INGREDIENTS AMOUNT______________________________________ 85.0 Water RODI 170,000 g 0.10 Sodium Benzoate 200 g 0.075 Carbopol 934P 150 g 0.10 Disodium EDTA 200 g 0.468 Potassium Metabisulfite 936 g 0.41 Potassium Acetate 820 g 0.25 Xanthan Gum 500 g1.0 g 1.7 5-Aminosalicylic Acid 3,400 g to complete Water RODI 20,000 g Water RODI QS to 200,000 g______________________________________
In three patients subjected to this therapy, the following results were reported:
1. a 32-year old female with no active ileal disease (had small ileectomy five years ago) experienced no side effects.
2. a 66-year old female with active small bowel Crohn's disease, from the duodenum to the ileum, started to improve in the third week of a 4g/day treatment regimen; bowel movements were down to 3/4 per day, no pain was experienced and the inflammatory indices improved. The patient had a total of 4 weeks of the 4g/day regimen followed by enteral feeding. She thus gained 15 pounds in weight and was discharged much improved with 3 formed bowel movements per day as compared to 15-18 per day on admission. 3. a 56-year old female with 3 inflammatory strictures in her small bowel, and having had a previous ileocolic resection, started to improve after 2 weeks of a 4 g 5-ASA/day regimen. On the 21st day of therapy she had gained 5 pounds in weight and was symptom-free. This patient was also on prednisone and enteral feeding.
These studies are impressive, demonstrating a clear clinical response in severe proximal Crohn's disease and a consequent avoidance of the need for further surgery. No clinical side effects were noted and renal function and hematology were unchanged. No new abnormalities developed in these patients.
The augmented availability of 5-ASA achieved through treatment by the method according to the invention is demonstrated by impressive clinical results showing that the 5-ASA is in topical contact with the inflamed portion of the bowel. Excessive absorption is avoided as it would limit the prolonged treatment of inflammation by direct contact.
The following results profile the characteristics of both short-term (single) and steady state administration of 5-ASA or like compounds to the small bowel as determined by plasma concentrations of 5-ASA and of the only major metabolite of 5-ASA identified in man, viz: N-acetyl-5-aminosalicYlic acid. Following the method of the present invention, both free and acetylated forms can be found in plasma within 1 to 2 hours post administration.
Plasma levels are negligible approximately 12 hours after dosing as shown in table 2. The absorption peak is in the range from 4 to 8 hours after treatment. Notably, absorption of 5-ASA into the blood is greater when compared to an equivalent dose administered rectally.
TABLE 2__________________________________________________________________________concentration in plasma in mcg/ml ofPatient SJM1 Patient NF Patient JAT Patient CSDhours after N-Ac 2 3 41 dose 5-ASA 5-ASA 5-ASA N-Ac 5-ASA N-Ac 5-ASA N-Ac__________________________________________________________________________0 0.032 0.056 0 0.747 0.012 0.01 0.099 0.2531 4.87 8.01 15.7 15.2 8.9 12.9 11.1 11.62 11 22.6 15.5 17.9 15.9 20.7 17.1 19.73 10.4 18.7 17.2 21.5 11.1 18.9 12.6 20.24 19.2 28.8 16.8 21.4 10.2 20.8 9.29 16.45 5.8 15.9 6.46 13.8 5.71 18.1 4.8 12.66 2.2 10.4 2.7 10 2.83 10.9 2.74 8.237 0.921 5.3 1.43 5.49 1.34 6.48 1.27 4.518 0.811 4.41 0.55 4.24 0.813 6.02 0.263 3.53 81/2 -- -- -- -- -- -- -- --12 0.02 0.506 0.119 2.22 0.085 1.2 0 0.94724 -- -- -- -- -- -- -- --__________________________________________________________________________ concentration Healthy in plasma in mcg/ml of Volunteers Patient JS Patient ML (n = 6) average 5 6 hourshours after N-Ac N-Ac after N-Ac1 dose 5-ASA 5-ASA 5-ASA 5-ASA 1 dose 5-ASA 5-ASA__________________________________________________________________________0 0.328 0.031 0 0.038 0 0.118 0.1891 10.3 13.5 6.55 9.32 1 9.57 11.752 15.2 23.5 8.49 14.9 2 13.86 19.883 25.4 35.9 10.1 22.3 3 14.46 22.924 15.7 28.1 9.39 20.8 4 13.43 22.725 6.17 19.4 7.85 22 5 6.01 16.976 2.12 11 -- -- 6 2.52 10.117 1.15 6.63 -- -- 7 1.22 5.688 0.473 4.22 0.34 6.21 8 0542 4.772 81/2 -- -- -- -- -- -- --12 0.052 0.811 0.577 1.83 11.5 0.142 1.2524 -- -- -- -- --__________________________________________________________________________
The concentrations in blood appear to be slightly higher and reached sooner in healthy volunteers as compared to Crohn's patients (table 3.). This phenomenon may be explained by the fact that Crohn's patients absorb lesser quantities of 5-ASA.
TABLE 3______________________________________ 5-ASA (time) N-Ac 5-ASA (time) mcg/ml mcg/ml______________________________________Patients 10.96 (4 h) 23.37 (6 h)Volunteers 14.46 (3 h) 22.96 (3 h)difference +3.5 mcg/ml -0.41 (+31.9%) (-1.7%)______________________________________
As shown in Table 4, urinary excretion accounts for about 1/3 the dose. 24 hour urinary analysis of patients undergoing treatment according to the invention reveals safe levels of both 5-ASA and N-acetyl 5-ASA throughout treatment. This confirms useful but not excessive availability of 5-ASA in the duodenum, jejunum, small bowel and subsequent segment, of the lower G.I. tract.
TABLE 4______________________________________urinary excretion after 24 hours post-treatmentamounts excreted in mg's amount excreted 5-ASA N-Ac 5-ASA______________________________________VolunteersJAT 832.5 1738SJM 995.8 1952.9CSD 90.6 634.2JWS 1163.4 1791.2NRF 1460.2 2300.8average 908.5 1683.4PatientsEP 747.5 1563.8LB 306.9 1494.5YAF 370.9 1535.4MD 214.65 1459.8WS 1109.6 269.8average 549.9 1750.3______________________________________
The urinary excretion appears slightly higher in volunteers (64.7%) as compared to patients (53.6%).
As noted above, overabsorption of 5-ASA is undesirable since it may be necessary for (for example jejunally instilled 5-ASA solution to retain some of its active ingredient by the time it reaches the colon. This would ensure that more distal areas of inflammation can successfully be treated by installation of 5-ASA solution in the proximal small bowel eg in cases of fulminant ulcerative colitis.
The treatment represented in this invention achieves this delivery profile as confirmed by analysis of 5-ASA and N-Ac-5-ASA in stools passed by patients undergoing treatment shown in table 5.
In analyses of faeces excreted on a given day after treatment initiation (1 dosage unit =4g of 5-ASA in 240 ml of suspension day) the following results (table 5) were obtained:
TABLE 5______________________________________fecal excretion after 9 hours post-treatment amountexcreted in mg's amount excreted 5-ASA N-Ac 5-ASA______________________________________VolunteersJAT 36.8 242.75SJM 13.2 92CSD 11.1 60.4JWS 16.9 498.5NRF 1.9 5ML 16.5 28.5average 16.06 154.7PatientsEP 7.4 23.51LB 400.7 53.6YAF 1.2 119.6EM 28.7 6.09MD 23.8 495.3WS 28.6 476.3average 81.7 195.8______________________________________
These results sow that both the active ingredient (5-ASA) and its metalolite (N-acetyl 5-ASA) are availble for therepeutic effect at the distal limit of the G.I. tract (anus). Also, the amounts found on the faeces of patients is higher than in volunteers (6.9% vs 4.2%), thus confirming a lower absorption in patients and illustrating availability of the tropically active ingredient to excert a topical antiphlogestic or lower gastrointestinal anti-inflammatory action on sites of inflammations along the lower G.I. track.
Serum levels furthermore demonstrate that 5-ASA is available in the serum should a systemic role be demonstrated. Furthermore, the fact that urinary clearance is not excessive and that a degree of fecal recovery occurs, shows that the method according to the invention may be used to deliver free 5-ASA to the entire lower G.I. tract beyond the point of administration.
CONTRAINDICATIONS FOR 5-ASA
Active peptic ulcer (possibly).
Hypersensitivity to salicylates.
Infants under 2 years of age.
Urinary tract obstructions.
WARNINGS
5-aminosalicylic acid should be used only after critical appraisal of the risk to benefit ratio in the following situations:
Liver and kidney disease.
Bleeding and clotting disorders.
Pregnancy and lactation
PRECAUTIONS
Periodic urinalysis to assess kidney function is recommended since prolonged 5-aminosalicylic acid therapy may damage the kidneys (see toxicology). Caution should be exercised when 5-aminosalicylic acid is first used in patients known to be allergic to sulfasalazine. The patients should be instructed to discontinue therapy at the first sign of rash or fever.
Drug interactions. No known drug interactions exist. The hypoglycemic effect of sylfonylureas may be enhanced. Interactions with coumarins, methotrexate, probenecid, sulfapyrazone, spironolactone, furosemide and rifampicine can not be excluded. Potentiation of undesirable glucocorticoid effects on the stomach is possible.
ADVERSE REACTIONS
Adverse reactions linked to the sulfapyridine moiety of sulfasalazine are avoided with the present invention. Hypersensitivity reactions have been reported in a sub-group of patients known to be allergic to sulfasalazine including rash, fever, and dizziness. The apparent frequency is estimated at 3-4% (15-51), with reactions occuring at the onset of therapy and resolving promptly following discontinuance.
In rare cases, following oral 5-ASA administration, exacerbation of ulcerative colitis characterized by cramping, acute abdominal pain and diarrhea has been reported. Acute pancreatitis, pericarditis, hepatitis, and pleural effusion have also been reported in association both with oral 5-ASA and SAS.
Other reported side effects include headache, flatulence, nausea, and alopecia, but do not appear to be common.
DOSAGE AND ADMINISTRATION
The suspension (4g 5-ASA per 240 ml) is administered on a daily basis during acute episodes of disease and at other times during the usual course of therapy is again one unit daily. Response to treatment and adjustment in dosing frequency should be determined by periodic examination, including endoscopy and the assessment of symptomatology including rectal bleeding, stool frequency, and general well-being.
Daily dosing is continued until a significant response is achieved or the patient achieves remission. Usually the dose can be reduced to alternate days or every third day, depending upon disease activity. Abrupt discontinuance of 5-ASA is not recommended. Dose tapering is recommended and serum levels in each patient should be titrated to meet individual needs. Maintenance therapy is recommended to assure continued remission. The dosing schedule, alternate day, every third day, or p.r.n. should be determined for each patient. If symptoms, diarrhea and rectal bleeding recur, dosage should be increased to the previous effective level.
In children between the ages of 2 and 12, use of the drug should be limited to situations where a clear benefit is expected.
PHARMACOLOGY
5-ASA is also known as 5-aminosalicylic acid, mesalamine (USAN), mesalazine, 5-amino-2-hydroxybenzoic acid or 5-ASA:. It has empirical formula C7H7N03 and a Mol. Wt. of 153.14.
The following is a comprehensive presentation of the results of pharmacologic tests conducted on 5-ASA.
In tests using the oral route of administration (mostly 500 mg/kg), no adverse effect of 5-ASA on the following parameters or in the following tests could be established: tremorine antagonism, hexobarbital sleep time, motor activity, anticonvulsant action (metrazol & electric shock), blood pressure, heart rate, respiratory rate (up to 10 mg/kg, i.v.), tocolysis (antispasmodic assay), local anaesthesia, antihyperthermal and antipyretic effects. In the paw-edema test with carrageen injection, 200 mg/kg per os proved ineffective, but 500 mg/kg 5-ASA per os exhibited mild antiphlogistic action. In the renal function tests (natriuresis and diuresis) no biologically relevant effects of 200 mg/kg per os were demonstrated. After 600 mg/kg, marked functional changes were observed: increases in both total urinary output, natriuresis and proteinuria. The urinary sediment contained increased numbers of erythrocytes and epithelial cells. Both potassium elimination and specific weight were reduced. It can be concluded from these experiments that even high doses of 5-ASA have no effect on vital parameters. Disturbances in renal function are to be expected only at dosages equivalent to a single dose at least 8 to 10 times the daily dose in man.
TOXICOLOGY
A full battery of animal toxicology studies including long-term carcinogenicity and toxicity studies provide a plethora of safety data. Hereinafter there is a list of these studies and report summaries of the 13-week and 6-month studies on rat and dogs respectively as well as a discussion of the nephrotoxic potential of 5-ASA.
List of 5-ASA Animal Toxicology Studies
1. ACUTE TOXICITY
Oral LD50 --Rats and Mice
IV LD50 --Rats and Mice
2. SUB-CHRONIC TOXICITY
4 and 13 week oral --Rats/(0, 40, 160 & 640 mg/kg/day)
3. CHRONIC TOXICITY
6-Month Oral --Dogs/(0, 40, 80 & 120 mg/kg/day)
18-Month Oral CA/toxicity --Mice
24-Month Oral CA only --Rats
4. LOCAL/MUCOSAL
(for Rectal Dosage Forms)
Primary eye irritation --Rabbits
Rectal Tolerability --Rabbits
Delayed Contact Sensitization --Guinea Pig
Rectal Mucosal Irritation --Dog
5. REPRODUCTION AND EFFECTS ON FETUS
Oral Embryotoxicity and Teratogenicity
Rats: 0, 80, 160, 320 mg/kg/day
Rabbits: 0, 55, 165, 496 mg/kg/day
Fertility, Segment I--Rats
Week Male Fertility--Rats
6. CARCINOGENICITY
Mutagenicity
Microsome Mutation Assay/Escherichia Coli
Mouse Micronucleus Assay
In vivo Sister Chromatid Exchange
Assay, Hamster Bone Marrow Cells
Fluctuation Test/Klebsiella
pneumoniae and Ames Test/
Salmonella typhrimurium
Carcinogenicity--see 3.b above
Brief summary of findings to date: Animal studies to date show the kidney to be the only significant target organ for 5-ASA toxicity in rats and dogs. At high doses, the lesions consisted of papillary necrosis and multifocal proximal tubular injury. In rats, the "no-effect" levels were 160 mg/Lg/day for females and 40 mg/kg/day for males (minimal and reversible tubular lesions seen) after 13 weeks of oral administration. In dogs, the "no effect" level in both males and females was 40 mg/kg/day after six months oral administration. Aside from gastric and heart lesions, bone marrow depression, (seen in some of the rats at the 640 mg/kg/level,) and, secondary effects of the kidney damage previously considered, no other sign of systemic toxicity was noted at daily doses up to 160 mg/kg in rats and 120 mg/kg in dogs for 13 week and six month periods , respectively.
Mucosal irritation studies in rabbits (5 day) and dogs (27 day) with rectally administered 5-ASA dosage forms indicated that 5-ASA was devoid of significant local irritation on rectal mucosa both macroscopically and microscopically.
The battery of tests completed shows that 5-ASA is devoid of embryotoxicity and teratogenicity in rats and rabbits; that it does not affect male rat fertility after 5 weeks oral administration at 296/mg/kg/day; that it lacks the potential to affect late pregnancy, delivery, lactation or pup development in rats; and that it is without mutagenic properties in a standard series of tests.
Nephrotoxic potential of 5-Aminosalicylic Acid.
Owing to its structural relationship both to phenacetin, the aminophenols and salicylates, 5-ASA was included in a series of compounds studied following identification of antipyretic-analgesic nephropathy in humans. Calder et al. (Brit. Med. J., 27 Nov. 1971; Brit. Med. J., 15 Jan. 1972; Xenobiot Vol. 5, 1975) reported that in rats in addition to the proximal tubule necrosis seen with aspirin and phenacetin derivatives, 5-ASA produced papillary necrosis following single intravenous doses ranging from 150 mg/kg to 872 mg/kg.
Diener et al (Archives of Pharm. 1986: 326:278-282) have shown that oral daily doses of 30 mg/kg and 200 mg/kg of 5-ASA for four weeks failed to produce any adverse effects on kidney function or histology in the rat.
In a 13-week study on rats, no renal lesion was detected after 4 weeks in the animals receiving up to 160 mg/kg orally per day. However, severe papillary necrosis and proximal tubular injury was seen in most animals receiving 640 mg/kg orally per day. At 13 weeks, the female animals were free of pathology with doses up to 160 mg/kg; minimal and reversible lesions in the tubules occurred in a few males (with no changes in renal function) at the 40 mg/kg level.
After six months oral administration in dogs, no toxicity was seen in the 40 mg/kg/day group. At 80 mg/kg/day, 2 of 8 treated showed slight to moderate renal papillary necrosis. These dogs as well as 2 others showed minimal to moderate tubular lesions. At 120 mg/kg/day, 2 females had slight papillary necrosis. These and 2 others showed minimal to moderate tubule injury.
Thus, the animal toxicity data suggest that 5-ASA has a nephrotoxic potential comparable to aspirin; on the other hand, extensive investigations of the problem of analgesic nephropathy have led to a current consensus that it is the combination of products that provides the greatest hazard, and that single ingredient antipyretic-analgesics such as aspirin are safe when taken in reasonable doses. See Emkey (Amer. J, Med., 24 June 1983) and Editorial (Amer. Pharm., May 1984).
It is important to note that despite 40 years' use of sulfasalazine world-wide for treatment and long-term prophylaxis of ulcerative colitis and Crohn's disease, there has been no report of kidney disease directly attributable to the drug or to the diseases being treated. The fact that sulfasalazine resulting in therapeutic levels of sulfapyridine might have led to kidney disease is taken as a systemic complication of inflammatory bowel disease, but applicants' are aware of no report listing kidney disease as a complication either of ulcerative colitis or of Crohn's disease.
While there have been shown and described what are at present believed to be the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made to them without departing from the scope of the invention as defined by the appended claims. | Transpyloric treatment of small bowel inflammation (e.g. Crohn's disease) by topical application of anti-inflammatory agents such as 5-ASA, 4-ASA or 3-ASA has hitherto been by oral administration of tablets the accurate targeting of which, in the variable environment of the gut, has been impossible. Now, by using an enteric feeding tube, an effective amount of an agent like 5-ASA may be delivered directly to the inflamed segment fo the gastrointestinal tract in patients suffering from inflammatory bowel disease whereby the agent is brough into direct, topical contact with inflamed mucosa while avoiding prior degradation in the stomach. | 0 |
BACKGROUND OF THE INVENTION
Until very recently, asbestos has been the standard, most widely used material in braided "compression" packings. The recent discovery of the potential carcinogenic effects, as well as the fact that supplies of the raw material are naturally limited as well as not widely distributed geographically and, hence, subject to political restraints, has caused a wide search for alternative materials in the fluid sealing industry. In a patent issued to one of us (U.S. Pat. No. 3,306,155), it was disclosed that the substitute material, namely, glass fiber, in combination with polytetrafluoroethylene (TFE) dispersion, forms a braided packing which is effective for a number of applications. However, in order to prepare a TFE dispersion, it is necessary to incorporate a wetting agent which then becomes residual in the braided structure. Where the glass fiber packing is used in contact with water or with an aqueous solution, the presence of the wetting agent makes it possible for the solution to gradually wash out the TFE lubricant after which self-abrasion of the glass fiber takes place rapidly. Where the aqueous solution is under pressure, the elution of the lubricant takes place even more quickly.
While each of the substitute materials on the market, such as glass fiber in combination with TFE dispersion, TFE fiber, graphite filament, etc., has substantial functional merit, these combinations are considerably more expensive than the standard graphited-asbestos packing which has been the predominant braided packing for many years. The search for an economical substitute which will be equivalent in cost to graphited-asbestos packing, has not yet been successful.
Attempts have been made to incorporate graphite lubricant or other inorganic lubricants into a braided glass fiber structure. These attempts have hitherto yielded unsatisfactory results. Dry, flake graphite will not be retained by a braided glass fiber structure. When the graphite is mixed with an oil lubricant, the oil will seep out and will not be retained; furthermore, the use of oil limits the effective operating temperature range of the packing. Also, the wet, dripping packing so constructed would create both housekeeping and safety problems. Adding graphite to a more coherent, waxy lubricant would help to retain the graphite in the structure, but this mixture would fundamentally amount to a wax filler in which the graphite would have no significant value; furthermore the wax would limit the effective temperature of the packing to a very low range. An aqueous graphite dispersion also will not be retained in the braided glass fiber structure.
Experience derived from graphited-asbestos packing offers no clear path to the development of a viable graphited glass fiber packing. The ordinary asbestos yarn of commercial grade or better used in the manufacture of braided packing contains up to 25% or even more of a cotton or rayon binder which readily absorbs and forms a reservoir of lubricant, permitting the finished product to retain the lubricant within the braided structure indefinitely. Furthermore, the inherent structure of asbestos, containing multifarious voids as the result of uneven and very small and varied fibers which are incorporated into the yarn (as opposed to the smooth, regular filamentary nature of glass fiber), permits the retention of graphite-laden lubricants (or mica-laden, talc-laden or other particulate-laden mixtures) as well as flake graphite in dry, powdered form. Thus, braided asbestos packing has been easy and convenient to load with lubricants and the technique of doing so is well known.
Attempts to use the same technique on braided glass fiber have met with failure owing to the difference between the inherent characteristics of this fiber and of asbestos fiber. These differences can readily be seen from the following table E and table G taken from pages 10 and 11 of the "Handbook of Asbestos Textiles," third edition, published by the Asbestos Textile Institute. Table E shows that asbestos fiber has a surface area which is as much as 70 times as great as that of nylon. Moreover, since as shown in table G, the diameter of glass fiber is roughly the same as that of nylon, the surface area of asbestos is also up to 70 times as great as that of glass fiber. It can readily be seen why graphite adheres so much more strongly to asbestos fiber than it does to glass fiber.
Lately, attempts have been made to use more sophisticated, aqueous-based graphite-laden dispersions for the same purpose. Such dispersions are available from Joseph Dixon Co., and, differing from the traditional mixture of graphite and oil, they do appreciably penetrate the glass fiber structure. However, similar difficulties have been found with such materials when used with glass or other inorganic fibers. They tend to wear off or, under pressure, blow out of a glass-fiber braided structure more readily than from braided asbestos, since they are not held and protected by the same irregular fibrous structure nor are they suspended in a retained lubricant vehicle. Also, when such dispersions are applied to glass fiber and the packing dries, a hairy, brush-like surface emerges on the outer surface of the packing. Since a prime desideratum of any packing is a smooth, antifrictional surface, such a packing becomes highly suspect from a tactile point of view to the normal user who is accustomed to use "smoothness" of finish as one of the criteria for packing evaluation.
TABLE E______________________________________COMPARISON OF SURFACE AREA OF VARIOUSFIBERS WITH ASBESTOS* SURFACE AREA BY N.sub.2 ADSORPTIONTYPE OF FIBER (SQ. CM./GRAM)______________________________________Nylon 3,100Acetate Rayon 3,100Cotton 7,200Silk 7,600Wool 9,600Viscose Rayon 9,800Asbestos 130,000 to 200,000+(Chrysotile)______________________________________ *Canadian Mining Metallurgical Bulletin, April, 1951 +Recent studies show that the maximum surface area may run as high as 500,000 sq. cm./gram.
TABLE G______________________________________COMPARISON OF DIAMETERS OF VARIOUSFIBERS WITH ASBESTOS*TYPE OF FIBER DIAMETER FIBRILS IN ONEFIBER (INCHES) LINEAR INCH______________________________________Human Hair 0.00158 630Ramie 0.000985 1,015Wool 0.0008 to 0.0011 910 to 1,250Cotton 0.0004 2,500Rayon 0.0003 3,300Nylon 0.0003 3,300Glass 0.00026 3,840Rock Wool 0.000142 to 0.000284 3,520 to 7,040Asbestos 0.000000706 to 0.00000118 850,000 to 1,400,000(Chrysotile)______________________________________ *Canadian Mining and Metallurgical Bulletin, April, 1951.
Accordingly, it would be highly desirable to develop a non-asbestos packing which enjoys the advantage of resilience contributed by suitable filaments and in which the solid lubricant is relatively inexpensive, and, most important, in which the solid lubricant is retained, even when subjected to contact with water or steam. The packing taught herein meets these objectives.
SUMMARY OF THE INVENTION
A packing material in accordance with the present invention, whether braided, knitted or both, derives its resilience and good thermal conductivity from inorganic fiber such as glass fiber, quartz fiber, ceramic fiber, carbon fiber, graphite fiber or a combination thereof, asbestos fiber being excluded from the category as the term, "inorganic fiber" will be used herein. To render the packing essentially leak-proof, the packing, in addition to the inorganic fiber, contains dispersed polytetrafluoroethylene (TFE) and is taken to a temperature high enough to decompose wetting agent used in preparation of the TFE dispersion but not high enough to sinter the particles of the dispersion. The decomposition temperature is generally considered to be from 375° to 600° F. but we have operated the decomposition step at temperatures as high as 650° F. The removal of the wetting agent by decomposition eliminates the danger of elution of the TFE when used in contact with water or steam. The TFE not only serves to prevent the passage of liquid through the packing but also serves as a lubricant, and, in addition can act, in quantities as low as 5%, based on the weight of inorganic fiber in the packing, to hold dispersed graphite in the packing when used in combination therewith. Dispersed graphite is a desirable component since it serves as an auxiliary low cost lubricant and can thereby reduce the need for the much more expensive TFE dispersion.
The quantity of dispersed TFE prior to removal of the wetting agent and associated water may vary some 5% to 100% based on the total weight of the fiber or fibers. However, due to its high price, it is preferably used in quantity from 5 to 20% based on the total weight of the fiber or fibers. As to the graphite, this may vary from 5% to 100% based on the weight of fiber and is preferably in the range of from 5% to 50% again, based on the weight of said fiber.
The packing may also include an organic fiber sufficiently stable thermally to withstand the temperature necessary to decompose the wetting agent used in preparing the TFE dispersion. A suitable organic fiber is TFE fiber. Another suitable fiber is aramid. The quantity of organic fiber used may vary from 5 to 75% of the total weight of the fibers and is preferably from 5 to 50%. Dispersed graphite may also be used in the packing containing organic fiber, the quantity of dispersed graphite varying between 5 and 100% of the weight of the fibers and being preferably between 5 and 50% of said weight.
The method of preparing the low-friction water and steam-resistant packing of the present invention comprises the steps of combining a suitable organic fiber with a TFE dispersion and raising the temperature of the combination to a level high enough so that the wetting agent normally present in the TFE dispersion is decomposed. If desired, graphite dispersion may be added prior to the heating step. Also, an organic fiber sufficiently stable thermally to withstand the temperature at which the wetting agent is decomposed may be combined with the inorganic fiber and TFE dispersion, either with or without added graphite dispersion. Suitable organic fibers are TFE fiber and aramid fiber. The decomposition of the wetting agent may be carried out in the temperature range of 375° F. to 650° F., temperatures in this range being insufficient to cause sintering of the TFE dispersion.
Accordingly, an object of the present invention is a packing of one or more inorganic fibers combined with dispersed TFE as a sealant and lubricant, said packing being essentially free of wetting agent.
Another object of the present invention is a packing based on an inorganic fiber to provide resilience in combination with dispersed TFE and further comprising either or both of an organic fiber and dispersed graphite, the packing being free of wetting agent and consequently resistant to penetration by water or steam.
A further object of the present invention is a low-friction, water and steam-resistant packing based on a fiber of an inorganic material selected from the group consisting of glass, ceramic, quartz, carbon and graphite, the packing including a TFE dispersion free of wetting agent.
An important object of the present invention is a method of preparing a low-friction water and steam-resistant packing based on an inorganic fiber in combination with a TFE dispersion, the combination being free of a wetting agent and where said combination may further comprise one or both of the materials namely, organic fibers and dispersed graphite, the organic fiber being of a material sufficiently stable thermally to withstand the temperature at which the wetting agent in the TFE dispersion is decomposed.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and a composition possessing the features, properties, and the relation of constituents, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings in which:
FIG. 1 is a view in perspective of a cut portion of a braided packing comprising an inorganic fiber and TFE dispersion free of wetting agent;
FIG. 2 is a similar view of a packing in which inorganic fiber yarn has been combined with organic fiber prior to braiding;
FIG. 3 is a similar view of a braided packing in which separate yarns of inorganic fiber and organic fiber has been braided together, the lubricant in the cases of FIGS. 2 and 3 being dispersed TFE with or without dispersed graphite, the packing being free of wetting agent; and
FIG. 4 is a similar view of a knitted packing in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, a braided packing in accordance with the present invention is indicated generally by the reference number 11. The packing comprises inorganic fibers 12 in combination with dispersed TFE 13, the braid being essentially free of wetting agent. The TFE functions as sealant against water or steam or organic solvents and as lubricant. In addition, it can serve as binder for dispersed graphite if incorporated as a second lubricant.
As aforenoted, it is important that the wetting agent normally used to form the TFE dispersion be removed since the dispersion is otherwise subject to elution when used as a packing in contact with water or water solutions. The problem is accentuated when the packing is used as a sealant against steam since steam penetrates packing very readily and can also wash out the TFE dispersion, if wetting agent is present thereby rendering the packing incapable of carrying out its intended double function, namely lubricating and sealing.
As inorganic fiber, the structural grade glass, chemical grade glass, electrical grade glass and the special glass fiber sold by Owens-Corning Company as Series AR (an alkali-resistant glass) may be used. Also, fibers of ceramic, quartz, carbon or graphite may be used for special applications, the last two being particularly resistant to a wide variety of chemical agents as well as operable at relatively high temperature. Also, the glass fiber may be texturized to increase its bulk as well as it resilience.
Since a principal objective of the packing of the present invention is to replace the relatively inexpensive asbestos packings, it is desirable that the quantity of the relatively expensive TFE dispersion used be as low as possible. It has been found that quantities as low as 5% by weight, relative to the quantity of inorganic fiber used can provide necessary characteristics. However, it is desirable for many applications that larger quantities of dispersed TFE be present and quantities as high as 100% based on the weight of inorganic fiber may be used. However, in general, it is preferable that the quantity of TFE dispersion used lie in the range from 5 to 40% weight, based on the weight of fiber.
As aforenoted, the diagonal lines in FIG. 1 given the reference 13, indicate TFE dispersion free of wetting agent. However, the diagonal lines in FIG. 1 are also to be taken as indicating the combination of the TFE dispersion in combination with dispersed graphite, the resulting combination being free of both moisture and wetting agent. It is desirable to incorporate the graphite due to its much lower cost than that of the TFE dispersion. As aforenoted, graphite has previously been used in combination with glass fiber but has been found to be unsatisfactory without a binder since under such conditions, it is readily washed or blown out of the packing. We had previously found that TFE dispersion (with wetting agent) can act effectively as a binder for the graphite so that the graphite dispersion can make it possible to achieve the desired lubrication with a smaller quantity of the much more expensive TFE dispersion. To our surprise we found that the TFE dispersion was more effective after freeing same of wetting agent with the economically beneficial consequence that a smaller and hence less costly quantity of TFE dispersion relative to powdered graphite can achieve the same results. The quantity of graphite used in such a combination may vary from 5 to 100%, based on the weight of fiber, but is preferably from 5 to 50%, based on the weight of said fiber.
We have also found that the inorganic fiber may profitably be combined with organic fiber for the purpose of minimizing self-abrasion of the inorganic fibers against each other and thus increasing the life of the packing, particularly where the packing is used against a moving shaft. The organic fiber must, of course, be sufficiently stable thermally so that it can be subjected to the temperature necessary to decompose the wetting agent. Suitable fibers are sintered TFE fiber and aramid fiber.
FIG. 2 shows a braided packing represented generally by the reference numeral 16 in which strands 17 each contain both organic fibers 18 and inorganic fibers 19 lubricated and sealed by dispersed TFE 21, with or without dispersed graphite, the entire structure being essentially free of wetting agent.
In the braid of FIG. 3, strands 31 and 32 are of inorganic fiber and strands 33 and 34 are of organic fiber, the entire braid being sealed and lubricated by TFE dispersion 35, either with or without dispersed graphite, the entire structure being free of wetting agent.
In the structures of FIGS. 2 and 3 the weight of organic fiber may vary from 5 to 100% and preferably from 5 to 50% of the total weight of the fibers. It should be noted that the Figures are not to scale. Again, the quantity of dispersed graphite present in the structures of FIGS. 2 and 3 may vary from 5 to 100% and are preferably from 5 to 50% of the weight of fiber present.
FIG. 4 shows a packing in which the reference numeral 41 indicates inorganic fibers in combination with TFE or aramid fibers, the combination being knitted to form a packing 42, and lubricated by dispersed TFE, and optionally TFE combined with dispersed graphite. The lubricant being indicated by the reference numeral 43. Again, the structure is essentially free of wetting agent.
The method of preparing the packings of the present invention comprises the steps of impregnating the packing either before or after forming into a braid or other shape with the planned lubricant-sealant and taking the temperature of the combination to a level such that the wetting agent present is essentially completely decomposed, the temperature level being below that necessary for sintering of the TFE dispersion. Preferably, the inorganic fiber is impregnated with the lubricant-sealant prior to braiding or knitting since the presence of a lubricant will help to avoid abrasion during the forming operation. Again, if organic fiber is to be used in combination with the inorganic fiber, it is desirable to form strands of the combination prior to braiding or knitting, the combination being less likely to abrade when each strand is of one material only.
Temperatures between 370° F. and 650° F. have been found suitable for decomposing the wetting agent without sintering the TFE dispersion.
As is well known, virtually no packing can be considered to be absolutely leak-proof, especially when subjected to a large difference in pressure. Packings containing wetting agent have been particularly susceptible to elution and loss of the necessary characteristics for maintaining adequate resistance to leakage of vessel contents therethrough. However, packings in accordance with the present invention have proved to be as resistant to water and steam leakage as to leakage of organic solvents. Moreover, this improved performance with respect to leakage has been achieved without any increase in the coefficient-of-friction of the packing, and, at relatively low cost.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method (process) and in the composition set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawing(s) shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Particularly it is to be understood that in said claims, ingredients or compounds recited in the singular are intended to include compatible mixtures of such ingredients wherever the sense permits. | A low-friction, water- and steam-resistant packing suitable for both static and dynamic applications includes inorganic fiber selected from the group consisting of chemical, electrical, structural and alkali resistant glasses, ceramic, quartz, carbon and graphite materials, and dispersed and dried, but unsintered, polytetrafluoroethylene (TFE). The packing is essentially free of wetting agent and is prepared by combining the inorganic fiber with a TFE dispersion containing a wetting agent and heating the resulting combination to a temperature high enough to decompose the wetting agent but insufficiently high to sinter the particles of the dispersion. | 8 |
This invention was made with Government support under Contract No. DE-AC03-76SF00098 between the U.S. Department of Energy and the University of California for the operation of Lawrence Berkeley laboratory. The Government has certain rights in this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to composite materials made using aerogel foam, and the process for the manufacture thereof. More particularly, the invention is based on the use and properties of aerogels.
Aerogels are open pore, low density solids (typically 5% solid) that are easily permeated by gases. Aerogels typically have a high surface area and can exhibit catalytic properties towards gas-phase reactions. Aerogels are made using sol-gel processing followed by supercritical extraction of the entrapped solvent. A combination of reacting fluids and solvents are mixed together and form a gel (a low density network of solids containing the solvents and liquid reaction products). To remove the solvent without destroying or altering the solid network, the gel is placed in a vessel and the temperature and pressure are raised above the critical point of the contained solvent. Thereafter the pressure is released. The resulting material is aerogel and is the starting point for this invention. Aerogels can be made of many materials including metal oxides, polymers, and carbon.
2. Description of Related Art Aerogels are known in the art. For example, aerogels have been described in U.S. Pat. No. 4,610,863 and U.S. Pat. No. 2,093,454 (S. S. Kistler, 1937); and in various articles, i.e. Aerogels, appearing in Scientific American, May 1988, Vol. 256, No. 5.
The aerogels described in the prior art are transparent arrays which can be utilized, for example, in windows, refrigerators (as insulation or as insulating windows), ovens (as insulation or as insulating windows), or in the walls and doors thereof, or as the active material in detectors for analyzing high-energy elementary particles or cosmic rays.
The uses of the aerogels of the prior art are somewhat limited, because they do not possess characteristics desirable for certain uses. For example, they are structurally weak and friable, can be broken down by water, and require vacuum-packing to attain their highest thermal-insulation properties.
SUMMARY OF THE INVENTION
It is an object of this invention to provide improved aerogels for thermal insulation applications.
It is a further object of this invention to provide a process for fabricating such improved aerogels.
It is still another object of this invention to provide an improved process for manufacture of aerogel composites.
It is still another object of this invention to provide aerogel composites having a variety of physical characteristics suitable for a plurality of purposes.
Other objects and advantages of the invention will become readily apparent from the following description.
The present invention relates to a new method of introducing additional solid phases into aerogel by the decomposition of vapors, and to the aerogel composite products produced thereby. This method can be used to produce a variety of composite materials using various aerogel compositions and deposited phases. In particular, the method of this invention has been used to increase the thermal resistance and improve the strength of silica aerogel insulation by adding carbon to the aerogel. The carbon blocks infrared radiation transfer to substantially reduce the thermal conductivity of aerogel insulation. Other aerogel composites produced by this method exhibit photoluminescence (silicon in silica aerogel) and ferromagnetic, paramagnetic, or superparamagnetic behavior (iron in silica aerogel).
The invention is a method to make new composite materials by introducing a gas into aerogel and using its high surface area and catalytic properties to decompose the gas to form a new solid phase in the aerogel network. The material produced in this way is unique in its structure and properties. Thermal decomposition of the gas within the aerogel generally takes place at significantly lower temperatures than it would in the free gas phase or on other solid surfaces. Thus the material preferentially deposits on the interior and surface of the aerogel to form a new composite.
DESCRIPTION OF THE INVENTION
A number of hydrocarbon gases and vapors have been decomposed in the aerogel to produce carbon-silica composites. We have demonstrated the catalyzed decomposition of methane, natural gas, commercial propane, acetylene, and vapors of xylene and furfuryl alcohol. The decomposition takes place at temperatures 100° to 500° C. lower than it would without the aerogel present. The decomposition usually takes place only in the aerogel and not elsewhere. Methane decomposition takes place in untreated aerogel at about 850° C., xylene at 450° C., and furfuryl alcohol at 350° C.
The rate of carbon deposition depends on the choice of gas and temperature. When deposition temperature is low (≦500° C.), further heat treatment (550°-650° C.) in an inert atmosphere is necessary in order to completely convert the deposited material to pure carbon. This conversion is useful to maximize the absorption of carbon for a given loading of carbon in aerogel. Small amounts of carbon (2-20%) deposited using this method can increase the thermal resistance for evacuated aerogel from R-20/inch to R-35/in or more. In non-evacuated aerogel the thermal resistance can be increased from R-8/in to R-11/in or more. Aerogel weights have been increased up to ten times the original weight by the deposition of carbon, which may be of use in applications other than insulation. Deposition times vary from a few minutes to more than 48 hours. After deposition, breaking open the aerogel monolith reveals a uniform blackness throughout the volume indicating homogenous carbon deposition. Shorter deposition times result in aerogel composites suitable for thermal insulation. Long deposition times using natural gas or acetylene result in a dense graphite-like solid with considerably enhanced strength and resistance to attack by water (untreated silica aerogel is destroyed by liquid water). This material has a point to point electrical resistance as low as one ohm and potential uses in electrodes, batteries, and computers.
Aerogel composites of a variety of materials can be produced using the method of this invention. Silicon-silica composites were prepared by the catalytic decomposition of dilute silane gas followed by a post-deposition heat treatment to induce crystallinity in the silicon. The resulting composites photo luminesce when illuminated by ultraviolet radiation. The intensity and wavelength of the peak of the photoluminescent curve can be controlled by the method used in the post treatment process. The photoluminescence is believed to be due to quantum confinement effects originating from extremely small silicon crystallites. The silicon-silica composite should be useful in a variety of opto-electronic devices.
Composites of silica and iron, iron and carbon, and various oxides of iron can also be produced using the method of this invention. Ferrocene, Fe(C 5 H 5 ) 2 infiltrated into aerogel is decomposed at temperatures as low as 100° C. to produce combined iron and carbon deposits and release hydrogen. Amorphous and crystalline deposits of carbon include graphite ring structures with diameters from 0.05-0.5 μgm. The resulting material can be heated in an oxidizing atmosphere to eliminate the carbon and produce an aerogel iron oxide composite. An iron oxide composite can be treated in a reducing atmosphere to produce deposits of metallic iron. Subsequent oxidation can induce several oxidation states of iron. The resulting composites exhibit ferromagnetic, paramagnetic, and possibly superparamagnetic properties.
Because aerogel effectively catalyzes gas phase decomposition, the method has applications much broader than the illustrative applications described above. In addition to silica aerogel, carbon or metal oxide aerogels can be used as the deposition matrix. For instance, decomposition of metal-carbonyl, organo-metallic, or any low-vapor-pressure compound or element can produce a variety of silica-metal, carbon-metal, silica-non-metal, carbon-non-metal, silica-semiconductor, or carbon-semiconductor composites. Other candidates include the gases and combinations of reactive or non-reactive gases used in chemical vapor deposition. By starting with aerogels made of differing materials, e.g. Al 2 O 3 , TiO 2 , NiO, ZrO 2 , or carbon, and introducing various gases for decomposition, a wide variety of composites can be produced. To enhance the process, the minimum temperature for vapor decomposition can be reduced by adding metal compounds during preparation of the aerogel in various ways. For example, dissolved nickel compounds can be added to the sol during preparation of silica alcogel before gelation. Nickel may also be added after gelation by soaking the gel in alcohol containing nickel compounds. After supercritical drying, these Ni-treated gels cause hydrocarbon gases to decompose at much lower temperatures than does untreated aerogel.
Aerogel composites with small amounts of deposited guest materials are likely to have the following characteristics: low thermal conductivity, high porosity and surface area, and intimate mixing of the aerogel and deposited material at a nanometer scale. Aerogels containing larger amounts of deposited material are likely to have the following characteristics: strength increased over that of the aerogel, lower porosity (50% or less), and high electrical conductivity, when deposited with metals or conducting solids.
Post treatments, such as infiltration of gases for deposition of additional or different materials or to induce chemical reactions, maturation under certain controlled conditions, or exposure to electromagnetic or other radiation, could result in composites with a variety of uses. In one example of a post treatment, infiltration of carbon-containing silica aerogel composites with Li could produce materials appropriate for electrochemical storage devices.
Because the guest phase is deposited as nanometer-sized matter, post treatment in a reactive atmosphere can produce nanometer-sized coatings on materials deposited earlier. Such composites have properties that depend on the dimensions of the particles initially deposited and those of the coating material. The properties of the nanometer-sized deposits can differ from those of the same material in bulk form because the individual particles are so small. This smallness may cause an interatomic spacing that differs from that of the bulk material, thereby altering the fundamental band structure. The small size of the deposited material may also induce quantum-confinement effects which result in energy levels that are different from those of the bulk material. These induced effects can give the composite useful optical, electrical, or physical properties, such as photoluminescence and super-paramagnetism. The resultant composite materials are useful for optical filters, lasers, or other active or passive optical, electrical, or magnetic devices.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides an efficient and inexpensive process for the manufacture of aerogel composites with properties improved over pure aerogel materials. Carbon-silica composites with twice the thermal resistance of untreated aerogel at ambient temperatures will reduce the thickness requirement for the same thermal performance and will result in the commercial viability of aerogels as insulation in appliances such as refrigerators, freezers, water heaters, and ovens. Aerogel composites with improved performance at temperatures up to 500° C. will have applications in insulating steam and hot water pipes for industrial, commercial, and residential applications. Other medium-high-temperature applications include use in aircraft and aerospace insulation. New high-temperature automotive batteries will require high performance thermal insulation provided by aerogel composites. Composites of silicon and iron with silica or other aerogels will find use in electrical display devices, magnetic cooling cycles, gas-separation media, gas-phase catalysts, and optical devices.
The objectives of the present invention are carried out by a process which comprises introducing pre-selected gases and vapors into the aerogel, and decomposing those gases and vapors in situ to produce an aerogel with deposited decomposition products of the gases and vapors in the pores of the aerogel. Post-treatment processes may be used to add further components to the composite, selectively remove components from the composite, or alter the chemical or physical state of the composite.
Basically, the process involves the conventional steps of preparing an aerogel, and thereafter introducing into the heated aerogel a gas, which when decomposed in situ, deposits guest nanoscale material in the pore structure of the aerogel, as a result of the decomposition of the gas. Secondary or tertiary (etc.) composites are formed by infiltration of an additional gas(es) or vapor(s) followed by additional decomposition steps to add further decomposition product(s) into the aerogel-composite. Post-conditioning under controlled conditions (vacuum, inert or reactive gases, long-term controlled temperature or pressure, exposure to electromagnetic or other radiation) may be used, which may alter the chemical, physical, or optical properties of primary, secondary or tertiary (etc.) composites. The invention thus further includes the results of decomposing additional materials in composites made from the aerogels which have the decomposition products of the gases deposited within the aerogel pores, and the products made from the aerogels and/or aerogel composites which have further decomposition or other alteration products associated with any secondary or tertiary (etc.) treatments.
The process of this invention is carried out in a reaction vessel. The reaction vessel has inputs for three gas streams, but should not be considered to be limited to just three flows; any number could be connected. At least one reactant gas and one carrier gas is introduced into the reaction vessel. Each gas has a flowmeter connected between the cylinder and the reaction vessel. Also connected is a vessel capable of containing materials of sufficiently low vapor pressure that they can be introduced into the reaction vessel by heating causing them to vaporize and enter the carrier gas stream; more than one such vessel could be attached. The reaction vessel is constructed of a non-reactive material, usually glass, quartz, metal, ceramic, or ceramic-coated metal. The reaction vessel contains both inlet and outlet places such that gases pass effectively around and through the aerogel/aerogel composite reactant material. More than one inlet is conceivable. The aerogel sample, or in the case of secondary or tertiary reactions (etc.), a previously prepared composite material is placed in the reaction vessel. The reaction vessel is surrounded by temperature control elements, usually heating elements, but cooling units are possible. For post-conditioning, the reaction vessel can be evacuated, filled with non-reactive or other gases, or placed in another chamber allowing long-term temperature control, or exposure to electromagnetic or other radiation.
An alternative procedure to prepare aerogel composites is to place the aerogel starting material in a closed container that also contains a liquid or solid that will vaporize when activated by heat or radiation. The vessel may first be evacuated to remove air and left evacuated or back-filled with an inert or reacting gas. Then the vessel is heated or activated by radiation to vaporize the decomposable gases. The vapor infiltrates the aerogel and decomposes to form the aerogel composite.
In either procedure, the rate of deposition of the decomposition products of the gas onto the wall structure of the pores of the aerogel depends on the choice of gas and the temperature used.
Preferred gases for carbon deposition are methane, natural gas, commercial propane, acetylene, and vapors of xylene and furfuryl alcohol.
These gases all decompose to deposit carbon on the walls of the aerogel pore structures. Weight increases in the aerogel due to the deposition have been achieved from less that 1% to more than 800%. Deposition times vary from a few minutes to 48 hours or more.
After deposition, the aerogel exhibits a uniform deposition throughout the volume in some cases and non-uniform deposition in other cases. Long deposition times using a natural gas result in a dense graphite-like solid with considerably enhanced strength and resistance to attack by water. This material has a point-to-point electrical resistance as low as 1 ohm.
Preferred gases for Si deposition are the silanes and halogenate silanes; germanium hydrides for Ge deposition, and for Fe and Fe/C deposition the preferred gas is ferrocene Fe(C 5 H 5 ) 2 ! or iron carbonyl. Similar organometallic substances, such as aryl chromium compounds, such as dibenzylchromium and others, or Cr(CO) 6 , or nickel carbonyl, Ni(acac) 2 nickel acetylacetonate!, Ni(C 5 H 5 ) 2 nickelocene!, are preferred gases for deposition of Cr or Cr/C and Ni or Ni/C, respectively. Metal carbonyls of cobalt, molybdenum, tungsten, ruthenium, osmium, and manganese are preferred gases for the deposition of those elements or element/C composites, respectively. Ti(C 5 H 5 )Cl 2 or V(C 5 H 5 ) 2 are preferred gases for the deposition of Ti or Ti/C and V or V/C, respectively. LiC or Li(C 5 H 5 ) would be a preferred choice for deposition of Li.
This process will be more fully understood by reference to the following examples, which are intended to be illustrative of the invention and not limiting thereof.
EXAMPLE 1.
Deposition of Carbon by Decomposition of Hydrocarbon Gases.
Small aerogel pieces were placed in a porcelain boat and loaded into a quartz-walled tube furnace. The furnace temperature was raised at a heating rate ranging from 5° to 20° C. per minute. An inert gas such as argon or nitrogen flowed into the reaction chamber initially and then the chosen hydrocarbon gas is introduced with or without a carrier gas once the desired deposition temperature has been reached. The deposition gas was introduced typically at a flow rate of 0.1 to 0.3 L/min for a few hours. After deposition, the darkened aerogel samples were cooled in inert atmosphere to prevent the oxidation of the deposited carbon.
Depending on the type of hydrocarbon gas used, the aerogels experienced a gradual darkening in color with increasing temperature and time. For example, in the case of natural gas (primarily methane, CH 4 ), the aerogels appeared clear at the beginning of deposition, turning tan when the deposition temperature reaches 700° C., brown at a deposition temperature of 730° C., dark brown at a deposition temperature of 750° C., and finally black at 770° C. As deposition proceeded, yellow to brown vapor was released from the quartz tube and liquid with a strong aromatic odor condensed on the effluent end of the quartz tube. On average, the weight of the aerogel doubled after deposition from flowing natural gas for about 5 hours although the deposition rate may change with time. The deposited carbon appeared to be distributed quite uniformly throughout the volume of the aerogel.
As expected, acetylene gas required a much lower temperature to decompose than did natural gas, depositing black carbon in aerogels at temperatures as low as 500° C. or less if a carbon was introduced into the aerogels earlier. It took less than an hour to double the weight of the aerogel indicating a faster deposition rate. Other hydrocarbon gases evaluated include pure methane, having an optimum deposition temperature of 850° C., and commercial propane with an optimum deposition temperature at 700° C.
EXAMPLE 2.
Deposition of Carbon by Decomposition of Vapors of Hydrocarbons that are in Condensed Phases at Room Temperature
Hydrocarbon liquids, such as xylene and furfuryl alcohol, provide another alternative for the deposition of carbon in silica aerogels. They were introduced into the reaction chamber either as vapors or liquid droplets using a carrier gas. The deposition temperature varied from 450° C. for xylene to 350° C. for furfuryl alcohol. After deposition, further treatment in an inert atmosphere at a higher temperature (>650° C.) was necessary in order to completely convert the hydrocarbon to carbon.
EXAMPLE 3.
Deposition of Silicon by Decomposition of Silane or Trichlorosilane
Silane, diluted to a concentration of 1.9% in argon for safety purposes, was introduced at a flow rate of 0.05 to 0.3 L/min, decomposing to brown silicon in silica aerogels at deposition temperatures as low as 450° C. But the deposition was far from uniform, being richer near the surface region of the aerogel. The uniformity was improved somewhat when hydrogen gas was added at a high flow rate to reduce the rate of the decomposition of silane.
Trichlorosilane is another source for the deposition of silicon in aerogels. Trichlorosilane, introduced by its own vapor or by bubbling argon (0.2 L/min) through it, decomposed to light brown silicon particles in the aerogel matrix at 550° C. More than 10% weight increase was achieved after depositing for only 1 hr. The aerogel became opaque and light brown, but the deposition appeared much more homogenous than that from the decomposition of silane.
Samples of silicon/silica aerogel composite became luminescent (under ultraviolet light) after being annealed in an inert atmosphere at temperatures above 700° C. and preferably aged at about 120° C. for a few hours.
EXAMPLE 4.
Deposition of Iron by Decomposition of Ferrocene
Ferrocene, Fe(C 5 H 5 ) 2 , though solid at room temperature, boils at 245° C. and has sufficient vapor pressure for deposition into aerogels when heated to about 100° C. Ferrocene vapor was transported by dry nitrogen at a flow rate of 0.1 L/min to the quartz reaction chamber, where it decomposed to finely divided iron/carbon particles throughout the aerogel. Alternatively, a container with ferrocene can be placed in a closed, evacuated chamber containing aerogel and heated to 100°-200° C. Depending on the quantity of material deposited, the samples were pyrophoric and glowed when exposed to air or oxygen, leaving a dark brown iron compound which was magnetic or paramagnetic. The weight increase was nearly 100% after deposition of 24 hours at 400° C. The color of the composite material changed from brown to light green upon heating in a reducing atmosphere, e.g. hydrogen to 450° C. Further heating to 700° C. in a reducing atmosphere results in a black material that has undergone considerable shrinkage. Exposure to air of the green material results in a composite that is black at ambient temperature and brown at relatively high temperatures (400°-500° C.).
EXAMPLE 5.
Decomposition of Ferrocene in a Closed Chamber
Solid ferrocene and silica aerogel were placed in a closed container that was either evacuated, or evacuated and back-filled with helium, at a pressure that ranges from a few hundred milli-torr to a few hundred torr. The container was heated to 100 to 200° C. for several hours. The resulting material contains very small carbon rings and tubes in addition to amorphous carbon and iron deposits. | Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel.
Also disclosed are the composites made by the process. | 8 |
[0001] This application is a Continuation-In-Part of U.S. application Ser. No. 11/863,823 filed Sep. 28, 2007, which is a Continuation-In-Part of Ser. No. 10/381,726 filed Aug. 12, 2003, which is the National Stage of International Application No. PCT/AU02/00725 filed Jun. 5, 2002, and claims priority to Application No. PR 8001 filed in Australia on Sep. 28, 2001 under 35 U.S.C. § 119. The entire contents of each of the above-applications is incorporated herein by reference.
[0002] This invention relates to aluminium cans filled with wine. It also relates to a process for packaging wine in aluminium cans.
BACKGROUND OF THE INVENTION
[0003] Wine has been produced since the times of the ancient Greeks. It has been stored in many types of containers. These have included timber, pottery and leather. The use of glass bottles has evolved as the preferred storage means for wine, particularly when stored in quantities less than one litre. While bottles are almost universally used, they have the disadvantages of having relatively high weight and being relatively fragile.
[0004] For beverages other than wine, such as beer and soft drinks, alternative packages such as metal cans and polyethylenetetraphthate (PET) bottles have been widely adopted. These offer advantages of lower weight and greater resistance to breakage. It has been proposed to store wine in such alternative containers. However, attempts to use such packaging types for wine have been generally unsuccessful. Some very low quality wines are stored in polyvinyl chloride containers. It is believed that the reasons for this lack of success in canning wine has been the relatively aggressive nature of the materials in wine and the adverse effects of the reaction products of wine and the container on the wine quality, especially taste. Wine is a complex product that typically has a pH in the range 3 to 4. This compares to beer with a pH of 5 or more and many soft drinks with pH 3 or more. However, pH itself is not the sole determinant, and it has been found that carbonated cola drinks with a pH as low as 3 may be adequately stored in PET containers. The low pH is the result of the phosphoric acid content in carbonated cola drinks. This may allow the satisfactory use of pre-coated aluminium cans and PET bottles for these beverages.
[0005] The packaging of wine in cans has been proposed but no prior attempt has been commercially successful. In Modern Metals (1981; p 28) Fred Church suggested packaging wine in two piece aluminium cans. by eliminating oxygen from the head space with nitrogen. This early proposal failed to achieve commercial success because the wines were not storage stable.
[0006] In 1992 Ferrarini et al in Ricerca Viticola Id Enologica no 8 p 59 reviewed the packaging of wine in aluminium cans. They also concluded that oxygen in the head space was to be avoided but that corrosion of the can was due to a number of contributing factors which needed to be addressed. Ferrarini noted that high internal pressures tend to accelerate the corrosion process and also indicated that pasteurization was necessary. Ferrarini et al concluded that using these guidelines white wine could be canned. One recommendation was that the wines must be pasteurised. Again these recommendations did not result in any commercially successful product. It has been realized that pasteurisation has detrimental effect on the taste and bouqet of wine and this may explain the lack of adoption of the Ferrarini recommendations.
[0007] It is an object of this invention to package wine in aluminium cans whereby the quality of the wine does not deteriorate significantly on storage.
SUMMARY OF THE INVENTION
[0008] The invention provides in one form a filled two-piece aluminium can containing a wine characterised in that it has less than 35 ppm of free SO 2 , less than 300 ppm of chlorides, less than 800 ppm of sulfates, and preferably less than 250 ppm of total sulfur dioxide; the can being sealed with an aluminium closure such that the pressure within the can is a minimum pressure sufficient to prevent buckling and damage to the lining, typically in the order of 20 psi. and wherein the inner surface of the aluminium can is coated with a corrosion resistant coating.
[0009] This invention is in part predicated on the discovery that the failure in prior art attempts to find a reliable and repeatable process was to concentrate on controlling the canning process rather than look for wine parameters that enable wine to be stored in an aluminium can for periods in excess of six months. This invention is also predicated on the realization that corrosion of the can body and the coating is caused by microholes and cracks in the coating surface and the high content of particular anions in an acidic environment. The anions that need to be kept below critical levels are chlorides and sulfates and to a lesser extent nitrites and nitrates. As taught in the prior art free sulphur dioxide and free oxygen levels also need to be controlled.
[0010] Preferably the wine is further characterised by having total nitrates less than 30 ppm, total phosphates less than 900 ppm and acidity calculated as tartaric acid in the range g/litre to 9 g/litre. Preferably the wine contains less than 1 ppm of nitrites. Preferably the maximum oxygen content of the head space is 1% v/v.
[0011] Preferably the increase in aluminium content in wine that is stored in the can for three months in the upright position at 30° C. is a maximum of 30%.
[0012] Preferably the corrosion resistant coating is a thermoset coating.
[0013] Preferably the head space after sealing with the closure has the composition nitrogen 80-97% v/v, and carbon dioxide 2-20% v/v. Preferably liquid nitrogen is added just prior to the seaming of the closure to the body of the can.
[0014] Alternatively the wine is carbonated before the two-piece can body is filled with the wine whereby the head space after sealing is predominantly carbon dioxide. The pressure within the can has a minimum pressure sufficient to prevent buckling and damage to the lining, in the nature of cracking of the internal lining coating, the minimum pressure typically being in the order of 20 psi.
[0015] Preferably the head space for a 330 millilitre can is in the range 2-5 mm.
[0016] Preferably the wine is chilled before filling.
[0017] In contrast to the recommendations of the prior art pasteurization is not necessary to obtain acceptable shelf life for a product that is acceptable to consumers.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The wine required for the process of the present invention may be prepared by the use of particular viticulture and wine making techniques as are described below.
[0019] Alternatively the wine may be prepared by treating wine with higher than specified levels of constituents and removing or lowering the content of these constituents to those required for the present invention. In this invention the term “wine” is used quite broadly and includes still and sparkling wine as well as fortified wines and wines blended with mineral waters and fruit juices.
[0020] With regard to viticulture, the absence of undesired materials may be obtained by ensuring adverse chemical sprays are not used. The use of chemical sprays needs to be monitored as this also affects the total build up of undesired chemicals in the final wine product. Most vine diseases need heat or humidity to flourish, unpruned vines enhances this dilemma further creating the need for chemical spraying.
[0021] Shade has a major role in producing grape quality, a higher incidence of botrytis, powdery mildew and down mildew. Once again this requires chemical intervention. Sulfur based fungicides can be used but they introduce unacceptable levels of sulfur. Unpruned vines have bunches which produce soggy wine with excessive herbaceous and abhorrent flavours. Light is one of the greatest natural assets, too often forgotten and taken for granted. The focus must be “a vine in harmonious balance” within itself With the correct ratio of grapes, leaves, canes, woods and roots within this balance occurring, minimal chemical intervention is required.
[0022] Excessive irrigation's legacy is an “out of balance” crop. A crop where there is a far too abundant canopy produces shaded fruit and in turn late ripening. Also excessive irrigation prior to harvest overloads the berry with water and chemical uptake, which alters the berry's natural state. Again this often requires a chemical counter measure further down the processing line. Drip irrigation with a constant electronic soil moisture monitor is the preferred option.
[0023] Preferably grapes will be hand picked (with careful attention not to excessively damage the fruit) and should be harvested in a cool (8° C.-16° C.) environment, preferably at night. Baume in the 13.0-14.0 range with pH 3.1-3.8 for “reds” and 10.0-13.0 Baume and pH 3.0-3.5 for “whites”. Minimal sulfur dioxide dusting is required so as to minimise wild yeast degradation. It is preferred to rely upon the wild yeasts for fermentation.
[0024] For red wines, crushing and de-stemming should occur as soon as possible and preferably within 12 hours of harvesting. De-stemming before crushing is highly recommended so as to produce a higher quality wine. The advantages are an improvement in taste by not containing astringent, leafy herbaceous stems. Possible alcoholic strength increases, by as much as 0.5%, because the stems which contain water and no sugar, absorb alcohol. An increase in colour occurs by avoiding the pigments in the stems. Fermentation with stems allows for more oxygen intake at an accelerated process. We do not require speed when fermenting, only stability and quality. After de-stemming and crushing the must is pumped to a fermentation vessel, adjusted with tartaric acid, yeast levels adjusted to requirements and a minimum sulfur dioxide addition.
[0025] The vessel is fitted with a bubble system so as to allow excessive fermentation gases out, and no oxygen in. Oxygen entry occurs only when punching occurs. This amount of aeration is important for yeast multiplication and complete sugar fermentation.
[0026] Punching down the skins (every 10-12 hours) at regular intervals and maintaining an ambient temperature of approximately 25° C. is crucial in the fermentation process. Dry-cap can allow oxidisation and higher or lower temperatures create their own nemesis on the fermenting juice. Stability during maceration being the key element during the next 14-21 days. Baume is constantly monitored with a daily reduction of 0.7-1.0, Baume being the “benchmark”. When the Baume reaches 0°-1°, the pomace or grape mass is “basket pressed”.
[0027] Pressing requires careful and astute monitoring. Over-pressing creates heavy astringents, phenolics and heavy coarse tannins. Balance pressing alleviates the need for eventual heavy chemical fining, unnecessary blending and chemical intervention.
[0028] At this stage the combination of free run juice and pressed juice is transferred to pre-sulfited, sterilised used or new American Oak, French Oak stored in a naturally controlled temperature environment. The temperature range is 15° C.-25° C. After filling, the barrels are hit a few times with a rubber mallet to dislodge air bubbles and refilled to within 25 mm of the barrel opening. The barrels are fitted with an air lock and the fermentation is allowed to proceed within the barrel. This process takes 3-4 months to complete (the time factor dependent on the humidity and temperature variations in the host environment). About this stage malo-lactic fermentation occurs, either by inoculation or naturally if it is endemic in the winery.
[0029] After fermentation is complete the barrel is racked, cleaned, sterilised, lightly sulfited, filled and air locks removed. After filling, the barrels are hit a few times with a rubber mallet to dislodge air bubbles, refilled and bunged. The barrel then positioned with the bung at 30° to the vertical.
[0030] Sediment needs to be removed from young wine so that yeast cells, bacteria cells and foreign organic substances which create putrid, reduced and hydrogen sulfite can be avoided.
[0031] Aeration is another natural progression in our quest for excellence. This factor facilitates the completion of yeast transformation and the eventual stability of the wine. Within the fermentation medium, different areas of sedimentation occurs, dictating free sulfur dioxide levels to form. Racking synergises these layers into conformity. Sulfiting requirements at this stage are thus more precise.
[0032] Frequency of racking is a contentious issue, a time frame of every two to three months in the first year is quite acceptable although in reality factors such as the size of the tank or barrel, temperatures in the cellars and type of wine will dictate the cellarmaster's decision. His skill and experience will determine the final requirements. Egg white fining at the rate of 1-3 per 100 litres is required to enhance the settling of the suspended material.
[0033] After ageing in casks for 12-18 months, racking at least 3-4 times, analysing, tasting, lightly sulfiting, (if 100% necessary) acknowledging the wine is sound, free from fermentable sugars and has completely undergone malo-lactic fermentation, the wine is ready for blending. This is the final reward for the efforts put forth in the preceding 12-18 months and the months leading up to harvest.
[0034] For white wine the grapes are de-stemmed before crushing. The pH of the juice adjusted to pH 3.0-3.4 with tartaric acid. Skin contact time dependent on grape variety, sourcing region, ambient temperature and the quantity of tannins or astringent phenolic requirements. The must drained under carbon dioxide addition.
[0035] Fermentation temperature is in the range 10-16° C. A sugar content reduction of between 0.4 and 0.8 Baume is the goal. After fermentation, the wine settling and racked 10 under carbon dioxide, sulfur dioxide addition occurs.
[0036] In all procedures pertaining to white wine, exposure to air is to be avoided at all costs, and a cool temperature environment is practised. Wine prepared as described above has a free sulfur dioxide level less than 35 ppm and a total sulfur dioxide level less than 250 ppm. The level of anions that may form acids, chlorides, nitrates and sulfates are less than the prescribed maxima.
[0037] The invention may also be applied to sparkling wine where nitrogen may not be required in the head space as the carbon dioxide may be sufficient to provide the required can strength.
[0038] The two-piece cans suitable for the present invention are cans that are currently used for soft drink and beer beverages. The can linings are also similar and are typically an epoxy resin combined with a formaldehyde based cross-linking agent. Typically the film thickness used is greater than that used for beer or soft drinks. Typically 175 mg/375 ml cans have been found to lead to a suitable film thickness. The internally coated can is baked at temperatures typically in the range 165-185° C. for twenty minutes. It is important to ensure a well cross-linked impermeable film to ensure excessive levels of aluminium are not dissolved into the wine on storage.
[0039] The can filling process involves the addition of approximately 0.1 ml of liquid nitrogen just prior to seaming the closure of the body. The internal pressure in the can is typically in the order of 20 psi.
[0040] Alternatively the wine can be carbonated by mixing the wine with carbon dioxide gas in equipment known as a carbonator. This type of equipment is well known and is extensively used in the soft drink industry.
[0041] As previously discussed, the storage stability of the wine in the aluminium can is vital. In contrast to bottled wine where the head space includes oxygen, the head space in the cans of the present invention have very low levels of oxygen. This means the wine does not “age” on storage.
[0042] For test purposes, the packaged wine is stored under ambient conditions for a period of 6 months and at 30° C. for 6 months. 50% of the cans are stored upright and 50% are inverted.
[0043] The product is checked at 2 monthly intervals for Al, pH, °Brix, head space oxygen and visual inspection of the cans, 6 cans inverted and 6 cans upright per variable. Visual inspection includes lacquer conditions, staining of the lacquer and seam condition. Samples are to be retained for 12 months. Sensory evaluation uses a recognised objective system by a tasting panel.
[0044] Results for storage evaluation of a white wine are set out in Table 1. A white wine has a lower pH on average than a red wine and is more severe test on storage stability.
[0000]
TABLE 1
Storage
°Brix (20° C.)
Orientation
Al mg/L
pH
Initial
6.7
—
0.5
3.40
3 months
6.9
Upright
0.65
3.47
3 months
6.5
Inverted
0.68
3.47
6 months
7.0
Upright
0.72
3.49
6 months
7.0
Inverted
0.68
3.50
[0045] The increase in the aluminium content in the wine after storage in a can is calculated as:
[0000] (100×aluminium content after storage−initial aluminium content) % initial aluminium content
[0046] For the wine stored for three months in the upright position at 30° C. this calculates, using the data in Table 1, as:
[0000] (100×0.65−0.5)%0.5=30%
[0047] For the wine stored for three months in the inverted position at 30° C. this calculates as:
[0000] (100×0.68−0.5%)%0.5=36%
[0048] Similar calculations from the data in Table 1 give an aluminium increase of 44% and 36% for upright and inverted storage after six months.
[0049] This data shows satisfactory storage after six months at 30° C. The acceptable quality of the wine was confirmed by the tasting panel.
[0050] In this specification, reference to values for analytes in wine, gas composition, dimensions, volumes and pressure refer to the values as determined under standard laboratory conditions of 20° C. unless the context provides otherwise.
[0051] Since modifications within the spirit and scope of the invention may be readily effected by persons skilled in the art, it is to be understood that the invention is not limited to the particular embodiment described, by way of example, hereinabove. | A filled two-piece aluminium can contains a wine that has less than 35 ppm of free SO 2 , less than 300 ppm of chlorides, less than 800 ppm of sulfates, and less than 250 ppm of total sulfur dioxide. The can is sealed with an aluminium closure such that the pressure within the can is at a minimum value necessary to prevent buckling of the can, typically 20 psi. The inner surface of the aluminium can is coated with a corrosion resistant coating. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional Application Ser. No. 61/855,942, filed May 28, 2013, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to authenticating and securing online purchases. More particularly, the present invention relates to facilitating a financial transaction only when requested from a trusted node. Specifically, the present invention relates to providing a unique identifier of a node to a financial institution for use in authenticating future financial transactions.
[0004] 2. Background Information
[0005] Increased use of communication and Internet technology has altered the landscape of information delivery and has affected numerous aspects of life, including commerce and finance. This technological development has enabled individuals to participate in various business transactions within an Internet marketplace. In these online transactions, electronic payments between transacting parties have become increasingly prevalent as the accessibility of the technology to enable such payments has increased. Internet-based vendors typically depend on electronic payment services and may accept a number of electronic payment instruments (e.g. credit cards, debit cards, etc.) and other electronic payment services such as the PayPal™ online payment service. Conventionally, in an online identification and authorization system the user is required to provide a user identification name and password and personal details in order to purchase content from a website or gain access to content. Along with this information, the user is required to provide the identification number of the payment instrument, for example a credit card number. The credit card number is cross-referenced with the owner's name and other basic personal details and if there is a match, the payment is authorized.
[0006] If a payment instrument number and associated data is stolen, a thief only needs to enter the information in the same manner as an authorized instrument holder. The systems which authorize and allow payments make no distinction between a thief entering the correct information or a true authorized entity entering the correct information, as long as the desired input matches. Thus, there is a tremendous need in the art for overcoming this significant security flaw in contemporary systems.
SUMMARY
[0007] In one aspect, the invention may provide a method for authenticating and securing online purchases, the method comprising the steps of: initiating an online payment of an amount from a payor to a payee, wherein the payor initiates the online payment via a computer system; providing, by the payor, a unique identifier of the computer system, a financial account identifier, and an amount to the payee; providing, by the payee, the unique identifier, the financial account identifier, and the amount to a financial institution associated with the financial account identifier; determining, by the financial institution, whether the unique identifier is associated with the financial account identifier; completing the online payment by crediting the payee the amount and debiting the payor the amount if the unique identifier is associated with the financial identifier; and rejecting the online payment if the unique identifier is not associated with the financial identifier.
[0008] In another aspect, the invention may provide a method for authenticating and securing online purchases, the method comprising the steps of: linking a node and a financial account, wherein the node includes a processor, a memory, and a logic circuit; allowing payment for online purchases via the financial account when the online purchase is initiated by the node; and disallowing payment for online purchases via the financial account when the online purchase is not initiated by the node.
[0009] In another aspect, the invention may provide a method for authenticating and securing online purchases, the system comprising: storing a plurality of financial account identifiers in a storage system of a financial institution; associating a first financial account identifier in the plurality of financial account identifiers with an account holder of the financial institution; entering a first unique identifier of a node associated with the account holder into a plurality of unique identifiers in the storage system of the financial institution; and associating the first unique identifier with the first financial account identifier in the storage system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0010] One or more preferred embodiments that illustrate the best mode(s) are set forth in the drawings and in the following description. The appended claims particularly and distinctly point out and set forth the invention.
[0011] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale.
[0012] FIG. 1 is a diagrammatic view of a node communicating with a financial institution of one embodiment of the present invention;
[0013] FIG. 2 is a diagrammatic view of two tables in a database of one embodiment of the present invention;
[0014] FIG. 3 is a diagrammatic view of a selection from the two database tables of FIG. 2 ;
[0015] FIG. 4 is a diagrammatic view of a communication path of one embodiment of the present invention;
[0016] FIG. 5 is a flowchart of one feature of one embodiment of the present invention;
[0017] FIG. 6 is a flowchart of one feature of one embodiment of the present invention; and
[0018] FIG. 7 is a flowchart of one feature of one embodiment of the present invention.
[0019] Similar numbers refer to similar parts throughout the drawings.
DETAILED DESCRIPTION
[0020] A system and method for authenticating and securing online purchases is shown in FIGS. 1-7 and referred to generally herein as system 1 . Various non-novel features found in the prior art relating to encryption techniques, online transactions, network communications, and financial database systems are not discussed herein. The reader will readily understand the fundamentals of these topics are within the prior art and readily understood by one familiar therewith.
[0021] As shown in FIG. 1 , system 1 includes a node 3 , which may be embodied by any off-the-shelf computing component having a processor 5 , a memory 7 , a communication module 8 , and a logic circuit 9 connecting processor 5 , memory 7 , and communication module 8 . Thus, node 3 may be embodied by a mobile telephone, a laptop computer, a desktop computer, a tablet, or any other electronic device. Node 3 further includes a unique identifier 11 , preferably stored in memory 7 and preferably represented digitally in a string of alpha numeric characters or derivable from a combination of variables stored in memory 7 or accessible by processor 5 . Unique identifier 11 may be any identifier unique to node 3 and which may be used to identify only node 3 . Thus, unique identifier 11 may be generated by node 3 , by an external algorithm, or provided to node 3 by a third party or another part of system 1 .
[0022] In one embodiment of system 1 , unique identifier 11 is the media access control address (hereinafter “MAC address”) assigned to node 3 . MAC addresses are unique identifiers assigned to network interfaces for communication on the physical network segment. MAC addresses are most often assigned by the manufacturer of a network interface controller (not shown) disposed in node 3 and are stored in its hardware, such as the controller's read-only memory or some other firmware mechanism. MAC addresses can be contrasted with an internet protocol address (hereinafter “IP address”), which is issued dynamically to node 3 and may be arbitrarily changed. MAC addresses are typically 48 bits long. This 48-bit address space contains potentially 2 48 or 281,474,976,710,656 possible MAC addresses. Newer machine access control schemes include 64-bit address, dramatically increasing the already large address space of the 48-bit MAC address scheme. In accordance with the above, MAC addresses are intended to be a permanent and globally unique identification mechanism for modern electronic communication devices, such as those embodied by node 3 .
[0023] Unique identifier 11 may be a composite or compilation of various features stored on node 3 . In one embodiment of system 1 , unique identifier may be embodied by a serial number associated with node 3 appended to the MAC address. This unique identifier 11 adds a high level of security as the serial numbers of nodes 3 are generally not broadcast across communication platforms as part of the commonly used communication protocols. Given a secure encrypted communication channel between node 3 and a communication partner, this embodiment of unique identifier 11 may be used to great benefit. In another embodiment, system 1 may use a checksum algorithm to compute a checksum datum off the MAC address and/or serial number and/or an encrypted block of data stored on node 3 . This checksum datum may then be used as part of unique identifier 11 , for example, by appending the checksum datum to the MAC address for use as unique identifier 11 .
[0024] Unique identifier 11 may be a combination of the MAC address or another string of digits and a bit-wise, decimal, hexadecimal, or any other style of representation of an image or graphic stored on node 3 . For example, a user may scan a fingerprint or acquire another style of image and store the image on node 3 . Unique identifier 11 may then be a bit-wise representation of the image. Alternatively, the MAC address and the photo representation may be appended to each other to form unique identifier 11 . Unique identifier 11 may alternatively be a voice or speech .wav file or another type of voice-representative data file for use in forming unique identifier 11 . Similarly, unique identifier 11 may incorporate a retina scan or an eye scan and the data file produced therefrom. Thus, the present invention encompasses any type of biometric data or data file which may be used and incorporated into unique identifier 11 .
[0025] Unique identifier 11 may alternative be an entirely new paradigm in the computing industry, whereby computer manufacturers systematically generate and provide unique identifier 11 to all nodes 3 at the time of manufacture. This system for assigning unique identifiers 11 may be implemented by agreement between computing companies or by an industry governing body, or possibly by mandate from the federal government.
[0026] Unique identifier 11 may be constructed dynamically as needed by node 3 . For example, by querying for the MAC address and the serial number of node 3 when unique identifier 11 is required. This prevents a pre-formed constructed unique identifier 11 from being stored on node 3 in an explicit manner which aids in preventing a hacker from simply downloading the file containing unique identifier 11 . In the event that node 3 does detect an intrusion or a possible hacking relating to unique identifier 11 , system 1 may be configured to alert law enforcement or the vendor or the financial institution of a possible fraudulent crime in progress.
[0027] Unique identifier 11 may be embodied in a phone number provided to a phone owner, which may represent node 3 . Thus, the user would transmit the phone number along with the data stream when using phone as node 3 to initiate a purchase. Unique identifier 11 may be embodied in a subscriber identity module or subscriber identification module (SIM), or any subcomponent thereof. The subscriber identify module is an integrated circuit that securely stores the international mobile subscriber identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephony devices, such as mobile phones and computers. A SIM circuit may be embedded into a removable plastic card. This plastic card is called a “SIM card” and can be transferred between different mobile devices. A SIM card contains its unique serial number, international mobile subscriber identity (IMSI), security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to and two passwords: a personal identification number (PIN) for ordinary use and a personal unblocking code (PUK) for PIN unlocking. Thus, unique identifier 11 may be embodied in one of the above unique variables or any combination thereof.
[0028] Unique identifier 11 may also be embodied in a driver's license number or a license plate number or any other type of unique number or signature assigned to the owner or user of that particular node 3 .
[0029] The owner or user of node 3 is also the owner or user of a financial account at a financial institution 15 . As shown in FIG. 1 , financial institution 15 includes a computer system 17 having at least a processor 19 , a communication module 21 , a storage system 23 , and a logic circuit 25 connecting processor 19 , communication module 21 , and storage system 23 . Logic circuit 25 may be dynamically formed as needed for busing data between processor 19 , communication module 21 , and storage system 23 . Storage system 19 may be any commonly used mechanism for storing information, including a database or a plurality of databases locally disposed at financial institution 15 , or disposed offsite or administered by a third party, or a combination of local and remote databases.
[0030] For organizational purposes, financial institution 15 provides a financial account identifier 27 for each account at financial institution 15 . Financial account identifiers 27 may be any method for identifying an individual account, including a social security number, a unique number or combination of alpha-numeric characters, or any other mechanism or method for tracking and identifying a financial account by computer system 17 . As shown in FIG. 1 , a list 28 of financial account identifiers 27 are stored in storage system 23 of computer system 17 associated with financial institution 15 .
[0031] As shown in FIG. 1 , the owner or user of node 3 uses communication module 8 of node 3 to establish a communication link 29 to communication module 21 of financial institution 15 , preferably via the World Wide Web. Communication link 29 is preferably an encrypted communication channel formed by passing login credentials and a password to financial institution 15 , as typically performed in the art when logging into a system. Once communication link 29 is established, the user has the option to initiate transmitting unique identifier 11 to financial institution 15 via communication link 29 . Providing the user the option of transmitting unique identifier 11 may come in the form of a website question/option button or graphic, or any other mechanism for providing the user the option to transmit or upload unique identifier 11 from node 3 to financial institution 15 via communication link 29 .
[0032] Once the user of node 3 transmits unique identifier 11 to financial institution 15 , financial institution 15 stores unique identifier 11 in storage system 23 and associates unique identifier 11 with the sender's financial account identifier 27 in list 28 . This association can be performed using any method commonly understood in the art. For example, by entering unique identifier 11 in a field in a database table and associating that field with another field in another database table containing list 28 of financial account identifiers 27 . Financial institution 15 may also store the user's name or some other way of identifying the user with respect to financial account identifier 27 as more than one user may be authorized to access that financial account and records may be kept for who is supplying which unique identifier 11 . Multiple users may be linked to one financial account identifier 27 and provided with a user specific name and password, for example, if multiple employees use a company credit card to perform services for the company. Thus, the company and/or financial institution may provide and revoke a user's login and password and remove the association with a particular financial account identifier.
[0033] FIG. 2 shows an exemplary embodiment of the storage system 23 in the form of a database 31 containing at least two database tables, list 28 embodied as a financial account identifier table 33 and a unique identifier table 35 . Financial account identifier table 33 includes a key column 37 and a financial account identifier column 39 . Entries in the individual fields of key column 37 include numbers or keys unique to key column 37 , for example, a linearly increasing integer such as 1, 2, 3, 4, 5, etc. Financial account identifiers 27 for all of the accounts operated by financial institution 15 are entered into individual fields in financial account identifier column 39 . Therefore, each row in financial account identifier table 33 includes a key field, found in key column 37 , and a financial account identifier field, found in financial account identifier field 39 . Unique identifier table 35 includes a key column 41 , a financial account identifier table key column 43 , and a unique identifier column 45 . Entries in the individual fields of key column 41 include numbers or keys unique to key column 41 , for example, a linearly increasing integer such as 1, 2, 3, 4, 5, etc. Entries in the individual fields of unique identifier column 45 include unique identifiers 11 transmitted by financial account holders at financial institution 15 to be stored by database 31 . Entries in the individual fields of financial account identifier table key column 43 include keys found in key column 37 of financial account identifier table 33 . This reference field links financial account identifiers 27 with unique identifiers 11 in database 31 .
[0034] One familiar in the art will recognize a database query may be formed to select a record from financial account identifier table 33 and thereafter select all the records in unique identifier table 35 with the financial account identifier table key column 43 equal to key column 37 of the selected record. This query will provide all of the unique identifiers 11 associated with a given financial account identifier 27 . As shown in FIG. 3 , for a given row in financial account identifier table 33 , the corresponding row(s) of unique identifier table 35 may be ascertained and retrieved. For example, if the row containing key column 37 C and financial account identifier column 39 C is selected from financial account identifier table 33 , the corresponding rows containing the key “2” are selected from unique identifier table 35 . In this example, those rows are the rows having key column 41 A and key column 410 , as both financial account identifier table key columns 43 A and 43 D contain the reference key “2”. As such, computer system 17 provides that financial account identifier 27 found in field 39 C is associated with unique identifiers 11 found in fields 45 A and 45 D.
[0035] After a user uploads or transmits a particular unique identifier 11 to financial institution 15 for association with the user's particular financial account identifier 27 , the user may end or close communication link 29 . Financial institution 15 retains the uploaded unique identifier 11 in storage system 23 for future use as an authentication and security feature. More particularly, financial institution 15 only permits a financial transaction involving that financial account identifier 27 if the request for a financial transaction is initiated from a particular node 3 having a matching unique identifier 11 stored in storage system 23 . In essence, financial institution 15 blocks all financial transactions involving a particular financial account associated with financial account identifier 27 which are not initiated via a node 3 having a previously uploaded unique identifier 11 associated with financial account identifier 27 . All requests for financial transactions initiated on non-authenticated nodes 3 are blocked and/or refused, preventing unauthorized financial transactions. As such, even if all of the user's financial information and credentials are stolen (financial account number, login ID, login password, etc.) financial transactions involving the compromised account are still prevented if the thief is not using an authorized node 3 to facilitate the fraudulent financial transactions.
[0036] Often, an individual wishes to initiate a financial transaction with a vendor. Therefore, the three parties to the financial transaction must coordinate and authenticate the financial transaction. As shown in FIG. 4 , a user uses node 3 A to establish a communication link 47 with a vendor 49 . Vendor 49 provides a good or service in exchange for payment. Vendor 49 may be an online retailer such as Amazon® or a similar online storefront or commercial entity such as an airline ticket payment system. In this example, the user of node 3 A wishes to buy a widget from vendor 49 for a particular price. The user of node 3 A actuates a purchase mechanism provided by vendor 49 , which transmits a data packet 50 from node 3 A to vendor 49 in the direction of Arrow A. Data packet 50 includes the user's financial account identifier 27 A and unique identifier 11 A of node 3 A. Vendor 49 receives data packet 50 and in turn establishes a communication link 51 with financial institution 15 . Vendor 49 then forwards or transmits data packet 50 to financial institution 15 over communication link 51 and in the direction of Arrow B. Using computer system 17 , financial institution 15 retrieves any unique identifiers 11 B, 11 C, etc. associated with financial account identifier 27 A. Processor 19 ( FIG. 1 ) then compares the received unique identifier 11 A with the stored unique identifiers 11 B, 11 C, etc. and determines whether unique identifier 11 A matches one of the stored unique identifiers 11 B, 11 C, etc.
[0037] Thereafter, a data packet 53 is constructed and sent via communication link 51 from financial institution 15 to vendor 49 in the direction of Arrow C. Data packet 53 contains an answer 55 . Answer 55 is the result of the comparison of whether unique identifier 11 A matches any unique identifiers 11 B, 11 C, etc. stored in storage system 23 ( FIG. 1 ) and linked to financial account identifier 27 A. For example, processor 19 ( FIG. 1 ) may determine that unique identifier 11 A precisely matches stored unique identifier 11 B. In this scenario, financial institution 15 transmits data packet 53 with an agreed upon message indicating that the financial institution 15 agrees to facilitate the requested financial transaction between the user and vendor 49 . Financial institution 15 then transmits the requested amount from user's account at financial institution 15 to vendor 49 and the transaction is successfully completed. Conversely, processor 19 ( FIG. 1 ) may determine that unique identifier 11 A does not match any stored unique identifiers 11 B, 11 C, associated in storage system 23 ( FIG. 1 ) with financial account identifier 27 A. In this scenario, financial institution 15 transmits data packet 53 with an agreed upon message indicating that financial institution does not agree to facilitate the requested financial transaction between the user and vendor 49 . Thereafter, financial institution 15 does not transfer any funds from the user's account at financial institution 15 to vendor 49 . System 1 may implement further logic or system methods to alert the owner of the financial account associated with financial account identifier 27 A that a fraudulent charge was attempted with the account owner's financial information. These alerts may take the form of emails, text messages, or phone calls.
[0038] The portion of system 1 residing on node 3 may be embodied in a precompiled and downloadable application which provides all of the benefits and features described above relating to node 3 . Thus, a user may purchase an application to provide these features or an entity such as financial institution 15 may provide the application for free. The user then downloads and installs the application on node 3 , which may be a phone, tablet, laptop computer, or any other type of computing device. The application may be programmed to read the node's unique identifier 11 and provide said unique identifier 11 to financial institution 15 for the initialization of system 1 . Thereafter, application may provide unique identifier 11 to either vendor 49 or financial institution 15 depending on the user's input and desires. The application may be precompiled and downloadable from online marketplaces such as iTunes® or Amazon® or from the financial institution's website.
[0039] As shown in FIG. 5 , system 1 may include a method 101 . Method 101 relates to determining whether a request for a financial transaction is authentic or fraudulent. Method 101 starts and moves to a step 103 . Step 103 determines whether the request for a financial transaction was made. If such a request was made, step 103 moves to a step 105 . If such a request was not made, step 103 loops back on itself to continuously consider whether a request for a financial transaction has been made. Step 105 compares the requesting node's unique identifier with any stored identifiers for the financial account requesting the financial transaction. Thereafter, step 105 moves to a step 107 . Step 107 determines whether the requesting node's unique identifier matches a stored unique identifier for the particular account requesting the financial transaction. If step 107 determines that there is a match, step 107 moves to a step 109 . If step 107 determines that there is not a match, step 107 moves to a step 111 . Step 109 allows or approves the requested transaction and thereafter ends method 101 . Step 111 disallows or disapproves of the requested transaction and thereafter moves to a step 113 . Step 113 alerts the owner of the financial account who requested the failed transaction. This may be via email, text message, phone call, or any other mechanism for alerting the listed owner of the account. Method 101 ends after step 113 is complete.
[0040] As shown in FIG. 6 , system 1 may include a method 201 . Method 201 relates to authenticating and securing online purchases. Method 201 starts and moves to a step 203 . Step 203 initiates an online payment of an amount from a payor to a payee via a node. After step 203 completes, step 203 moves to a step 205 . In Step 205 , the payor provides a unique identifier of the node, a financial account identifier, and an amount to the payee. After step 205 completes, step 205 moves to a step 207 . In step 207 , the payee provides the unique identifier, the financial account identifier, and the amount to the financial institution associated with the financial account identifier. After step 207 completes, step 207 moves to a step 209 . Step 209 determines whether the unique identifier is associated with the financial account at the financial institution. If step 209 determines that the unique identifier is associated with the financial account at the financial institution, step 209 moves to a step 211 . If step 209 determines that the unique identifier is not associated with the financial account at the financial institution, step 209 moves to a step 213 . In step 211 , the online payment is completed by crediting the payee the amount and debiting the payor the amount. Method 201 ends after step 211 is complete. In step 213 , the online payment is rejected and not completed. Method 201 ends after step 213 is complete.
[0041] As shown in FIG. 7 , system 1 may include a method 301 . Method 301 relates to authenticating and securing online purchases. Method 301 starts and moves to a step 303 . Step 303 links a node and a financial account and moves to a step 305 . Step 305 determines whether an online purchase was initiated requesting funds from the financial account. If step 305 determines that an online purchase was initiated requesting funds from the financial account, step 305 moves to a step 307 . If an online purchase was not initiated requesting funds from the financial account, step 305 loops back on itself. Step 307 determines whether the online purchase requesting funds from the financial account was initiated by the node. If step 307 determines that the online purchase was initiated by the node, step 307 moves to a step 309 . If step 307 determines that the online purchase requesting funds from the financial account was not initiated by the node, step 307 moves to a step 311 . Step 309 allows payment for the online purchase via the financial account. Method 301 ends after step 309 is complete. Step 311 disallows payment for the online purchase via the financial account. Method 301 ends after step 311 is complete.
[0042] “Logic,” “logic circuitry,” or “logic circuit,” as used herein, includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. For example, based on a desired application or needs, logic may include a software controlled microprocessor, discrete logic like a processor (e.g., microprocessor), an application specific integrated circuit (ASIC), a programmed logic device, a memory device containing instructions, or the like. Logic may include one or more gates, combinations of gates, or other circuit components. Logic may also be fully embodied as software. Where multiple logics are described, it may be possible to incorporate the multiple logics into one physical logic. Similarly, where a single logic is described, it may be possible to distribute that single logic between multiple physical logics.
[0043] Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity of explanation, the illustrated methodologies are shown and described as a series of blocks, it is to be appreciated that the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example methodology. Blocks may be combined or separated into multiple components. Furthermore, additional and/or alternative methodologies can employ additional, not illustrated blocks.
[0044] In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.
[0045] While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating there from. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims. | The present invention relates to authenticating and securing online purchases. The present invention recognizes that an account holder may initiate a financial transaction from a home computer, cellular telephone, or some other electronic device or node which the account holder controls. Prior to initiating an online purchase, the present invention requires the account holder to upload or provide a unique identifier associated with the node to the financial institution associated with the financial account of the user. The financial account may thereafter check whether the request for an online transaction was initiated with the trusted node by comparing the unique identifier of the requesting node with the unique identifier on file for the user. If the unique identifiers match, the financial institution authenticates the financial transaction and allows it to proceed. If the unique identifiers do not match, the financial institution rejects the financial transaction. | 6 |
BACKGROUND
[0001] Modern oil field operators demand access to a great quantity of information regarding the parameters and conditions encountered downhole. Such information typically includes characteristics of the earth formations traversed by the borehole and data relating to the size and configuration of the borehole itself. The collection of information relating to conditions downhole, which commonly is referred to as “logging,” can be performed by several methods including wireline logging, “logging while drilling” (LWD), and tubing-conveyed logging.
[0002] In wireline logging, a probe or “sonde” is lowered into the borehole after some or all of the well has been drilled. The sonde hangs at the end of a long cable or “wireline” that provides mechanical support to the sonde and also provides an electrical connection between the sonde and electrical equipment located at the surface of the well. In accordance with existing logging techniques, various parameters of the earth's formations are measured and correlated with the position of the sonde in the borehole as the sonde is pulled uphole.
[0003] In LWD, the drilling assembly includes sensing instruments that measure various parameters as the formation is being penetrated, thereby enabling measurements of the formation while it is less affected by fluid invasion. While LWD measurements are desirable, drilling operations create an environment that is generally hostile to electronic instrumentation, telemetry, and sensor operations.
[0004] Tubing-conveyed logging, like wireline logging, is performed in an existing borehole. Unlike wireline logging, tubing-conveyed logging enables a logging tool to travel where a wireline-suspended tool cannot, e.g., in a horizontal or ascending borehole. Tubing-conveyed logging tools typically suffer from restricted communications bandwidths, meaning that acquired data is generally stored in memory and downloaded from the tool when the tool returns to the surface.
[0005] In these and other logging environments, measured parameters are usually recorded and displayed in the form of a log, i.e., a two-dimensional graph showing the measured parameter as a function of tool position or depth. In addition to making parameter measurements as a function of depth, some logging tools also provide parameter measurements as a function of azimuth. Such tool measurements have often been displayed as two-dimensional images of the borehole wall, with one dimension representing tool position or depth, the other dimension representing azimuthal orientation, and the pixel intensity or color representing the parameter value.
[0006] Once a borehole has been drilled, operators often wish to perform downhole formation testing before finalizing a completion and production strategy. Fluid sampling tools enable operators to draw fluid (i.e., gas or liquid) samples directly from the borehole wall and measure contamination levels, compositions, and phases, usually based on the properties (e.g., optical properties, electrical properties, density, NMR, and PVT properties) of the materials drawn into the sample chamber. Existing downhole fluid analysis tools may have a limited reliability due to, e.g., insufficient instrumentation to perform in-situ analysis, or conversely, too many moving parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Accordingly, there are disclosed in the drawings and detailed description specific embodiments of methods, systems, and downhole tools that employ spatial heterodyne integrated computational element (“SH-ICE”) spectrometers. In the drawings:
[0008] FIG. 1 shows an illustrative environment for logging while drilling (“LWD”).
[0009] FIG. 2 shows an illustrative environment for wireline logging.
[0010] FIG. 3 shows an illustrative environment for tubing-conveyed logging.
[0011] FIG. 4 shows an illustrative formation fluid sampling tool.
[0012] FIGS. 5A-5C show illustrative embodiments of a SH-ICE spectrometer based fluid analyzer.
[0013] FIGS. 6A-6D illustrate a wavelength-to-spatial fringe relationship.
[0014] FIG. 6E shows an illustrative combined spatial fringe intensity.
[0015] FIG. 6F shows an illustrative spatial fringe image.
[0016] FIG. 7A shows an illustrative multiplex integrated computational element (“ICE”
[0017] FIG. 7B shows an illustrative spatially-dependent ICE.
[0018] FIG. 7C shows an illustrative multiplex spatially-dependent ICE.
[0019] FIG. 8 is a flowchart of an illustrative downhole fluid analysis method.
[0020] It should be understood, however, that the specific embodiments given in the drawings and detailed description do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed in the scope of the appended claims.
DETAILED DESCRIPTION
[0021] Various systems and methods for performing optical analysis with combined spatial-heterodyne (“SH”) integrated computational element (“ICE”), or “SH-ICE” spectrometer, Light from a light source encounters a material to be analyzed, such as a formation fluid sample, a borehole fluid sample, a core sample, or a portion of the borehole wall. The encounter can take various forms, including transmission (attenuation) through the sample, reflection from the sample, attenuated total reflectance (evanescent wave), scattering from the sample, and fluorescence excitation. In any event, the spectral characteristics of the material are imprinted on the light beam and can be readily analyzed with the spectrometer to obtain a measure of characteristics of the substance such as concentrations of selected components. The disclosed spectrometer is believed to be capable of laboratory-quality measurements in a wide range of contexts including a hostile downhole environment,
Context
[0022] The disclosed systems and methods are best understood in the context of the larger systems in which they might be employed. FIG. 1 shows an illustrative logging while drilling (LWD) environment. A drilling platform 2 supports a derrick 4 having a traveling block 6 for raising and lowering a drill string 8 . A kelly 10 supports the drill string 8 as it is lowered through a rotary table 12 . A drill bit 14 is driven by a downhole motor and/or rotation of the drill string 8 . As bit 14 rotates, it creates a borehole 16 that passes through various formations 18 . A pump 20 circulates drilling fluid through a feed pipe 22 to kelly 10 , downhole through the interior of drill string 8 , through orifices in drill bit 14 , back to the surface via the annulus around drill string 8 , and into a retention pit 24 . The drilling fluid transports cuttings from the borehole 16 into the pit 24 and aids in maintaining the integrity of the borehole.
[0023] A LWD tool 26 is integrated into the bottom-hole assembly near the bit 14 . As the bit extends the borehole 16 through the formations 18 , logging tool 26 collects measurements relating to various formation properties as well as the tool orientation and various other drilling conditions. The logging tool 26 may take the form of a drill collar, i.e., a thick-walled tubular that provides weight and rigidity to aid the drilling process. As explained further below, tool assembly 26 includes a optical fluid analysis tool that monitors wellbore fluid properties. A telemetry sub 28 may be included to transfer measurement data to a surface receiver 30 and to receive commands from the surface. In some embodiments, the telemetry sub 28 does not communicate with the surface, but rather stores logging data for later retrieval at the surface when the logging assembly is recovered.
[0024] At various times during the drilling process, the drill string 8 may be removed from the borehole as shown in FIG. 2 , Once the drill string has been removed, logging operations can be conducted using a wireline logging tool 34 , i.e., a sensing instrument sonde suspended by a cable 42 having conductors for transporting power to the tool and telemetry from the tool to the surface, A wireline logging tool 34 may have pads and/or centralizing springs to maintain the tool near the axis of the borehole as the tool 34 is pulled uphole. As explained further below, tool 34 can include a formation fluid sampler that extends a probe against a borehole wall to draw fluids into a sample analysis chamber. A surface logging facility 44 collects measurements from the logging tool 34 , and includes a computer system 45 for processing and storing the measurements gathered by the logging tool.
[0025] An alternative logging technique is logging with coil tubing. FIG. 3 shows an illustrative coil tubing-conveyed logging system in which coil tubing 54 is pulled from a spool 52 by a tubing injector 56 and injected into a well through a packer 58 and a blowout preventer 60 into the well 62 . (It is also possible to perform drilling in this manner by driving a drill bit with a downhole motor.) in the well, a supervisory sub 64 and one or more logging tools 65 are coupled to the coil tubing 54 and optionally configured to communicate to a surface computer system 66 via information conduits or other telemetry channels. An uphole interface 67 may be provided to exchange communications with the supervisory sub and receive data to be conveyed to the surface computer system 66 .
[0026] Surface computer system 66 is configured to communicate with supervisory sub 64 during the logging process or alternatively configured to download data from the supervisory sub after the tool assembly is retrieved. Surface computer system 66 is preferably configured by software (shown in FIG. 3 in the form of removable information storage media 72 ) to process the logging tool measurements (including the fluid component measurements described further below). System 66 includes a display device 68 and a user-input device 70 to enable a human operator to interact with the system software 72 .
[0027] In each of the foregoing logging environments, the logging tool assemblies preferably include a navigational sensor package that includes directional sensors for determining the inclination angle, the horizontal angle, and the rotational angle (a.k.a. “tool face angle”) of the bottom hole assembly. As is commonly defined in the art, the inclination angle is the deviation from vertically downward, the horizontal angle is the angle in a horizontal plane from true North, and the tool face angle is the orientation (rotational about the tool axis) angle from the high side of the wellbore. In accordance with known techniques, wellbore directional measurements can be made as follows: a three axis accelerometer measures the earths gravitational field vector relative to the tool axis and a point on the circumference of the tool called the “tool face scribe line”. (The tool face scribe line is typically drawn on the tool surface as a line parallel to the tool axis.) From this measurement, the inclination and tool face angle of the logging assembly can be determined, Additionally, a three axis magnetometer measures the earth's magnetic field vector in a similar manner. From the combined magnetometer and accelerometer data, the horizontal angle of the logging assembly can be determined.
[0028] FIG. 4 shows an illustrative formation fluid sampler tool 80 . Tool 80 can be a drill collar, a coil tubing joint, or a drilling tubular, but most commonly it is expected to be part of a wireline sonde. Tool 80 extends a probe 82 and a foot 84 to contact the borehole wall 17 , typically driving them outward from the tool body using hydraulic pressure. The probe 82 and foot 84 cooperate to seat the probe 82 firmly against the borehole wall 17 and establish a seal that keeps borehole fluids from being drawn into the tool 80 . To improve the seal, the wall-contacting face of the probe 82 includes an elastomeric material 85 that conforms to the borehole wall 17 . A pump 86 draws down the pressure, prompting fluid to flow from the formation through a probe channel 88 , a sample chamber 90 in fluid analyzer 92 , and a sample collection chamber 94 . The pump 86 exhausts fluid into the borehole 16 through a port 96 and continues pumping until a sampling process is completed. Typically, the sampling process continues until the tool 80 determines that the sample collection chamber 94 is full and any contaminants have been exhausted. Thereafter the sample collection chamber 94 is sealed and the probe 82 and foot 84 are retracted. If desired, the tool 80 can repeat the process at different positions within the borehole 16 . Sample collection chamber 94 may be one of many such sample collection chambers in a cassette mechanism 98 , enabling the tool 80 to return many fluid samples to the surface.
Spatial-Heterodyne Integrated Computational Element Spectrometer
[0029] FIGS. 5A-5C show illustrative embodiments of a SH-ICE spectrometer based fluid analyzer. In FIG. 5A , a light source 502 shines light through an inlet window 504 into a sample (shown here as fluid flow stream 506 ). The light source 502 can he either broadband or narrowband. For the purposes of this disclosure, the term “broadband” is used to distinguish from narrowband sources that provide only isolated peaks in their spectrum. The broadband sources contemplated for use downhole have continuous spectrums in the range of 200-400 nm (for UV absorption and fluorescence spectroscopy), 1500-2300 nm (for special purpose spectroscopy, e.g. GOR (gas to oil ratio) determination), and 400-6000 nm (for general purpose VIS-IR spectroscopy), These examples are merely illustrative and not limiting. One readily available source suitable for this purpose is a tungsten-halogen incandescent source with a quartz envelope, generating light across the 300-3000 nm range. Arc lamps, broadband fluorescent sources, broadband quantum light sources, or a combination of a number of relatively narrowband light sources (such as LEDs) may also be suitable light sources. Suitable narrowband light sources are lasers and single wavelength LEDs, Such narrowband light sources may be used for single wavelength excitation spectroscopy (e.g. Raman and Fluorescence).
[0030] The illustrated sample is a fluid flow stream 506 sandwiched between the inlet window 504 and an outlet window 508 . Windows 504 and 508 are made from a transparent material (e.g., quartz, diamond, sapphire, zinc selenide) so that the main effect on the spectrum of the light is produced by attenuation as the light passes through the fluid flow stream 506 (i.e., transmission spectroscopy). Other spectrometer configurations may cause the light to interact with the sample (which, in some tool configurations, may be a surface of a solid) via reflection, diffuse reflection, attenuated total reflectance, scattering, or fluorescence. Conversely, some spectrometer embodiments cause the light to pass multiple times through the sample to increase the transmission-induced attenuation.
[0031] The light from the sample chamber may captured by a collimation element such as a mirror or lens 510 . Spectrometer embodiments employing a narrowband source would typically include a notch filter 511 to block the central frequency emitted by the light source 502 to prevent the intensity at this wavelength from overwhelming the measurements at nearby frequencies, The notch filter 511 can be positioned anywhere on the optical path after the sample (e.g., fluid flow stream 506 ).
[0032] One or more apertures 512 may be positioned at various points along the optical path to define the light into a beam and limit the effects of the beam periphery. A dispersive two-beam interferometer 514 employs a beam splitter 516 to split the incoming light beam into two beams that travel along first and second optical paths before being recombined by the beam splitter 516 into an outgoing beam. (A 50/50 splitter is preferred, but not required.)
[0033] Light traveling along the first path interacts with a diffraction grating 518 or other dispersive element that reflects the light at an angle that is dependent on its wavelength, in other words, the beam that returns to the splitter has the spectral components propagating with wavelength-dependent wavefront angles. Similarly, the light traveling along the second path interacts with a second diffraction grating 520 or other dispersive element that produces a return beam with spectral components propagating with wavelength-dependent wavefronts angles. The dispersive elements 518 , 520 are positioned to provide the opposite wavefront angles. As the outgoing beam reaches a detector 530 , the difference in propagation angles produces a set of interference fringes. As explained below with reference to FIGS. 6A-6E (taken from Roesler, U.S. Pat. No. 5,059,027, “Spatial Heterodyne Spectrometer and Method”), the fringes vary based on the wavefront angle.
[0034] For a baseline or reference wavelength λ 0 , the wavefront angles in both beams are aligned, producing no fringes as indicated in FIG. 6A , Graph 602 shows that the intensity as a function of position on a detector (e.g., detector 530 in FIG. 5A ) is constant at this wavelength. As the wavelength increases, the wavefront angles of the two beams become increasingly different. FIG. 6B shows the wavefronts at an angle that produces one fringe on the detector (the intensity variation in graph 604 results when the path difference between the wavefronts varies from −λ/2 on one edge of the detector to +λ//2 on the other edge). FIG. 6C shows the wavefronts at an angle that produces two fringes on the detector (the intensity variation in graph 606 results when the phase difference between the wavefronts varies from −λ to +λ. As indicated in FIG. 6D , each increment of the wavelength by a value δλ adds one fringe across the width of the detector. (Graph 608 shows n fringes across the width of the detector.)
[0035] FIGS. 6A-6D illustrate examples of what occurs when only a single wavelength is present. When multiple wavelengths are present, the intensity vs. position relationship becomes more complex, as indicated by graph 610 in FIG. 6E . Nevertheless, a spatial Fourier transform can separate out the contributions from the individual wavelengths.
[0036] The actual image cast by the outgoing beam on the detector is two dimensional. FIG. 6F (excerpted from a figure in N. Gromer et al., “Raman spectroscopy using a spatial heterodyne spectrometer: proof of concept”, Appl. Spectroscopy v65, n8, 2011) shows an illustrative two dimensional image 612 . Along the width of the detector (i.e., in the x-dimension), the image demonstrates a complex fringe dependence, whereas along the height of the detector (i.e., in the y-dimension) the intensity is relatively constant. The signal-to-noise ratio may be improved by summing or averaging the columns of the image together before analyzing the fringe structure.
[0037] Returning to FIG. 5A , the foregoing discussion neglects the presence of element 522 , which as explained in greater detail below, is an integrated computation element (ICE) that modifies the outgoing beam image before it strikes detector 530 . The ICE 522 is included to exploit the observation that, in addition to spatial intensity variation, the image also contains wavelength-dependent intensity (“color”) variation, enabling further processing to be done on the image before it is captured by the detector 530 .
[0038] The ICE 522 operates to weight the various spectral components of the outgoing light beam by corresponding amounts, the weighting template being chosen based on what fluid properties are being measured. Many ICE implementations are known and potentially suitable, including a transparent substrate carrying a multilayered stack of materials having contrasting refractive indices, e.g., silicon and silica, niobium and niobia, germanium and germania, MgF and SiO. Suitable substrates may include BK-7 optical glass, quartz, sapphire, silicon, germanium, zinc selenide, zinc sulfide, various polymers (e.g., polycarbonates, polymethylmethacrylate, polyvinylchloride), diamond, ceramics, and the like. A transparent protective layer may further be provided over the layers with contrasting refractive indices. The relative weightings of different wavelengths are achieved through a judicious selection of the number, arrangement, and thicknesses of the layers to provide various degrees of optical interference at selected transmitted (or reflected) wavelengths. Other illustrative ICE implementations achieve the wavelength-dependent weightings by suitably varying their transmissivity, reflectivity, absorptivity, dispersivity, and/or scattering properties. Such implementations may employ engineered materials, holographic optical elements, gratings, acousto-optic elements, magneto-optic elements, electro-optic elements, light pipes, and digital light processors (DLPs) or other types of micro-electronic mechanical (MEMs) based light manipulation devices.
[0039] FIG. 7A shows an illustrative ICE 702 of the multi-layered contrasting-refractive index variety. The illustrated ICE 702 is a multiplex device having different multi-layered structures over different image regions 704 , but it is also contemplated that there may be only a single region 704 over the entire substrate surface. The regions 704 are continuous across the width of the device. Hereafter this type of region is described as “row-oriented”. There is no horizontal spatial dependence to the ICE, meaning that, when employed as ICE 522 in FIG. 5A , each of the image fringes is processed based solely on their wavelengths. Nevertheless, the fidelity of the fringe measurement is increased by the suppression of irrelevant wavelength intensities (and hence the spatial fringes irrelevant to the fluid property measurement). Note that this ICE embodiment can be positioned nearly any here in the optical path.
[0040] The use of different ICE structures in corresponding row-oriented regions enables different ICE templates to be applied simultaneously. As the number of regions increases, however, the size of each region decreases correspondingly, reducing the total tight intensity associated with each measurement. In some embodiments, this loss may be compensated by lengthening the measurement time.
[0041] When the image is captured by a detector 530 ( FIG. 5A ) such as a ICCD (intensified charge coupled device), it is digitized and suitable for digital signal processing. (Other image capture detectors would also be suitable.) As previously mentioned, the processing may include combining measurements from different rows (albeit, different rows within the same region 704 ) to increase the signal to noise ratio, and may further include a spatial Fourier transform to derive the spectral content of the ICE-filtered outgoing beam. Such processing can be done using a software or firmware programmed general purpose processor, or an application specific integrated circuit. Fourier transform processing of the weighed or unweighted spatial pattern would allow for a system that uses SH-ICE to gather spectral data in-situ for calibration or re-calibration.
[0042] In most cases, however, it is expected that a Fourier transform would not be required, but rather the information in each row could be combined (averaged or summed) together to obtain a single value representative of the ICE-specific measurement (e.g., an analyte concentration). Such a measurement can be performed using software or hardware (e.g., an appropriately wired detector) or, as indicated in FIG. 5B , a minor or lens 524 that focuses the information from each row onto a row-associated point, yielding a one dimensional line. An array of photodetectors 540 may be provided along the line to enable each photodetector 540 acquire a row-associated measurement. Because the imaging array is now only one-dimensional, it can be further simplified to, a single photodetector 540 and a scanning mirror. The photodetector 540 can take the form of a photodiode, a thermal detector (including thermopiles and pyroelectric detectors), a Golay cell, or a photoconductive element. Cooling can be employed to improve the signal-to-noise ratio of the photodetector 540 .
[0043] Whether the recombining of spatial fringe information is done optically ( FIG. 5B ) or electronically ( FIG. 5A , after image capture by detector 530 ), signal to noise ratio may be improved by combining the measurements associated with all of the rows in a given region 704 .
[0044] In FIGS. 5A and 5B , ICE 522 operates on the transmitted light. The systems can be readily modified to employ the reflected light, as indicated in FIG. 5C . ICE 526 has a wavelength-dependent reflectivity to provide the desired spectral weighting on the fringes that reach detector 530 . Still other system embodiments measure both the transmitted and reflected light to achieve even higher performance. However, a similar performance is achievable with a multiplex ICE 702 having a regions 704 with complementary ICE templates, or by employing at least one ‘reference’ region that is weighted to a constant value (e.g. neutral density) or left as an unweighted (clear) region.
[0045] FIG. 7B shows an alternative ICE 712 that employs a spatial dependence to provide the desired spectral weighting. It employs regions that are continuous across the height of the device, i.e., along the y-axis, Hereafter, this type of region is described as “column-oriented”. Because the spatial dependence corresponds to selected fringes, the wavelength selectivity of the regions can be relaxed. Indeed, some contemplated embodiments employ a mask that equally attenuates all wavelengths in that region of the beam. However, it is believed that the best efficiency will be achieved when at least some wavelength selectivity is combined with at least some spatial dependence, and the highest degree of performance should be achievable when the both the geometry and wavelength selectivity are carefully tailored to the desired measurement.
[0046] FIG. 7C shows an illustrative multiplex ICE 722 in which each row-oriented region 724 employs a spatially-dependent ICE structure. As before, the use of multiplexing enables multiple simultaneous measurements, though it does so by corresponding reducing the light intensity available for each measurement.
[0047] An alternative to a multiplex ICE is the use of multiple ICES that can be sequentially positioned in the light path, e.g., with the use of a rotating filter wheel. As yet another alternative, the ICE can be dynamically changed, e.g., with a programmable acousto-optic ICE (for changeable wavelength dependence) or a programmable electro-optic ICE (for changeable spatial dependence). Dynamically changeable ICEs may use individually controllable pixels of a liquid crystal tunable filter or an acousto-optical tunable filter. Other programmable ICEs include but are not limited to DLP or other types of MEMS based devices.
[0048] FIG. 8 is a flowchart of an illustrative downhole fluid analysis method. It includes operations represented by blocks shown and described in sequential order, but this sequence is solely for explanatory purposes. In practice, the operations may be performed concurrently or, if sequential, may be performed in a different order or asynchronously.
[0049] In block 802 , the driller positions the fluid analysis tool downhole, e.g., in a wireline sonde or a LWD collar. In block 804 , fluid (e.g., from the formation) is drawn into a sample cell. In block 806 , the light source is energized and calibrated, in some embodiments, the calibration is performed by measuring light received from the source via a path that bypasses the fluid sample, A measurement correction may be derived from this measurement. In addition, or alternatively, a feedback signal may be derived from a measurement based on the output from the light source and used to adjust the light intensity applied to the fluid sample.
[0050] In block 808 , the tool illuminates the fluid sample with light from the source and analyzes the transmitted, reflected, or scattered light using a SH-ICE spectrometer, As discussed previously, the spectrometer obtains measurements indicative of fluid properties such as analyte concentrations. In block 810 , these measurements are processed, either by the tool itself or by a surface facility, to derive the fluid properties. Illustrative properties include amount and type of hydrocarbons (e.g., fractions of saturated, aromatics, resins, and asphaltenes), amount and type of gas phase (e.g., CO 2 , H 2 S, etc.), amount and type of liquid phase (e.g., water cut), PVT properties (including bubble point, gas-to-oil ratio, density variation with temperature), concentrations of compounds such as concentration of treatment fluid, and amount of contamination (e.g., drilling fluid) in formation fluid sample.
[0051] In block 812 , the tool and/or the surface facility communicates and stores the derived information. Contemporaneously, or later, the information is displayed to a user, preferably in the form of a log. In block 814 , the operation of the tool is optionally adjusted in response to the measurement, e.g., by terminating a pumping operation when the contamination level falls below a predetermined threshold.
[0052] The SH-ICE embodiments shown in FIGS. 5A-5C employ a series of discrete optical elements arranged along an optical path, which may further include additional mirrors, lenses, apertures, switches, filters, sources, and detectors. Some contemplated embodiments employ an integrated (“monolithic”) light path component. The integrated component provides reduced sensitivity to temperature changes, pressure changes, vibrations, and shock. A solid block of transparent material (e.g., quartz, sapphire, zinc selenide) is used as the body of the integrated component. Mirror gratings 518 , 520 , beam splitter 516 , also made of the same material, ICE 522 . (or ICE 526 ), and focusing element 524 , are fused or otherwise attached to this body without any air gaps to maintain the alignment and spacing of the components over a wide range of temperature, pressure, vibration, and shock conditions.
[0053] Some tool embodiments, rather than being fluid analyzers, analyze a solid that is visible through a window or aperture, such as a core sample or a portion of the borehole wall adjacent to the tool. In such embodiments, the tool tracks the motion of the tool relative to the solid, associating the measurements with time and/or position to construct an image of the sample's surface.
[0054] Various techniques to maximize the quality of the measurements would be known to one of ordinary skill in the oil field industry and can be employed. For example, the tool may be outfitted with a reservoir of a reference fluid for downhole calibration of the system and for compensating for contamination on the windows of the flow cell. Detector cooling or temperature compensation can be used Co minimize the effects of temperature drift in the electronics.
[0055] Various other features can be incorporated into the tool. For example, scattered light can be analyzed to determine the size distribution of particles entrained in a fluid flow. An ultraviolet light source can be included to induce fluorescence in the material, which fluorescence can be analyzed to aid in determining composition of the sample.
[0056] The spectrometer designs and methods disclosed herein may be used in technologies beyond the oil field including, for example, the food and drug industry, industrial processing applications, mining industries, or any field where it may be advantageous to quickly determine a spectrally-related characteristic of a material. These and other variations, modifications, and equivalents will be apparent to one of ordinary skill upon reviewing this disclosure. It is intended that the following claims be interpreted to embrace all such variations and modifications where applicable. | A spatial heterodyne spectrometer may employ an integrated computational element (ICE) to obtain a measure of one or more fluid properties without requiring any moving parts, making it particularly suitable for use in a downhole environment. One illustrative method embodiment includes: directing light from a light source to illuminate a sample; transforming light from the sample into spatial fringe patterns using a dispersive two-beam interferometer; adjusting a spectral weighting of the spatial fringe patterns using an integrated computation element (ICE); focusing spectral-weight-adjusted spatial fringe patterns into combined fringe intensities; detecting the combined fringe intensities; and deriving at least one property of the sample. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to refrigeration systems and particularly such systems as employed on board a motor vehicle for providing cooling of a compartment such as the passenger compartment for the vehicle. Currently automotive vehicle passenger compartment air conditioning systems typically employ an engine driven compressor for circulating refrigerant through an exothermic heat exchanger or condenser to an expander for dropping the pressure of the refrigerant for circulation through an endothermic heat exchanger or evaporator located for cooling a flow of air thereover directed to the passenger compartment. The refrigerant is returned to the compressor inlet from the evaporator for recirculation. Typically the compressor is operated by an electrically energized clutch for connecting the compressor to the engine.
Heretofore, such automotive air conditioning systems have proven generally effective; however, the means of controlling the flow of refrigerant to the evaporator for cooling the passenger compartment in the face of varying ambient thermal loading has been accomplished either by utilizing a temperature sensor on the evaporator and using the sensed temperature to control compressor clutch cycling, or by utilizing a pressure sensor in the refrigerant line disposed between the evaporator outlet and the compressor inlet with the pressure switch controlling the compressor clutch. Alternatively, it is known to utilize a temperature sensor in the refrigerant line at the evaporator inlet.
When an automotive A/C system is working under certain conditions, such as higher cooling capacity output (high vehicle speed and engine RPM ), and low cooling load (low blower speed @ recirculation mode or low ambient temperature @ outside air mode), and higher relative humidity of air, the condensate separated from the moist air will freeze on the fins of the evaporator if the condensate temperature reaches 0° C. (32° F.) or below. The frozen condensate will then block the air stream passing through the evaporator, reduce heat transfer effectiveness between the cold refrigerant and the hot air, and will cause the refrigerant system to malfunction, and eventually cause discomfort in the passenger compartment.
In order to prevent condensate freezing on the evaporator and to maintain the normal operation of the air conditioning system, one of the following three different control means has been utilized, namely a system having 1.) a temperature sensor installed in the refrigerant line (cold control); 2.) a pressure transducer installed in the refrigerant line (pressure control); and 3.) a temperature sensor inserted between the fin arrays in the air side of the evaporator (fin sensor control). Each of these system arrangements requires a corresponding control strategy and algorithm to (a) use the temperature or pressure outputs obtained from the temperature sensors or pressure transducer mentioned above as the control parameter(s); (b) use the background information obtained from other subsystems/components ( e.g., blower speed selection, air quality door position, ambient conditions, clutch cycling status, etc. ) through on-board real-time communications; (c) define a set point or operating zone based upon the real-time background information; (d) compare the real-time data input(s) with the defined set point or operating zone and calculate the error(s) between the set point or operating zone and the real-time data input(s); and (e) make control decision and command the desired control action(s).
In systems employing a fin temperature sensor that is inserted among the fin arrays on the evaporator surface, problems have been encountered; namely: 1.) it is very difficult, if not impossible, to define a meaningful sensor location on the evaporator surface. Theoretically, the coldest spot on the surface should be chosen as the sensor location to prevent the evaporator from freeze up. In reality, however, the coldest spot moves randomly around the evaporator surface dependent upon the operating and ambient conditions, as indicated by testing. This uncertainty has resulted in low quality of data inputs, poor accuracy of control, and longer calibration time, and 2.) the complexity of interfacing the sensor with other components has caused difficulty in packaging the system.
Problems have also been encountered in a system employing a pressure sensor; namely: 1.) the occurrence of rapid pressure changes occurring during the compressor clutch cycling which creates less temperature accuracy, whereas, the purpose of the freeze up prevention is to control temperature. There is a one-to-one relationship between the pressure value and the temperature value when the refrigeration system operates at steady-state condition. This one-to-one relationship does not exist when the refrigeration system operates in a dynamic mode; and, thus it is extremely difficult to control temperature based upon the pressure input; 2.) it is relatively costly, and, it has more parts and interfaces which makes packaging more difficult.
In the operation of the above described system, the cabin air temperature control is accomplished by controlling the refrigerant flow entering the evaporator through cycling the clutch of compressor. When the clutch is engaged, the compressor pumps refrigerant through evaporator which provides cooling to the blower air stream. When the compressor clutch is disengaged, the compressor stops and no refrigerant flows through evaporator. In actual vehicle operation, the cycling frequency ranges normally from 0 to about 6 cycles/min. The dynamic on/off cycling rate of the clutch has a substantial impact on the stability of cabin air temperature control. In this regard, the control algorithm developed should improve or optimize refrigerant system performance through balancing the needs of evaporator freeze up prevention and cabin air temperature quality (stability).
In order for the control algorithm fulfill its task providing accurate and optimum temperature control an accurate sensor must be provided and properly located. The control strategy and algorithm which will be used to control the clutch cycling operation based on the sensor signal are thus critical.
It has been thus desired to provide a sensor arrangement and algorithm for an automotive air conditioning system to operate the compressor clutch in accordance with a systematic control strategy that will maintain optimum compressor operation for preventing the formation of ice on the evaporator and yet provide the desired cooling and comfort level for a passenger compartment irrespective of the ambient conditions experienced during vehicle operation or the particular blower speed settings and air flow operation selected by the vehicle operator. It has further been desired to provide such a control sensor and algorithm integration for an automotive air conditioning system which is low in cost and easy to install during vehicle manufacturing.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a refrigeration system utilizing temperature sensor preferably in the form of a transducer disposed to sense refrigerant temperature preferably at the evaporator outlet or alternatively at the evaporator inlet in a system employed for on-board vehicle refrigeration and particularly for a vehicle passenger compartment air conditioning system. The transducer provides an electrical signal to a controller which is programmed with an algorithm to provide disengagement of the refrigerant compressor clutch in time to prevent evaporator icing irrespective of ambient conditions, the selected blower motor speed or the air flow type of system operation insofar as the mix of the ambient and recirculated blower air flowing over the evaporator. The system is calibrated for a particular type or style of vehicle passenger compartment configuration with the range of available blower speeds and air flow mixture for a range of ambient conditions; and, an algorithm is developed which provides the desired cooling and prevent the formation of evaporator icing during actual vehicle operation.
The present invention thus provides an on-board vehicle refrigeration system, particularly suitable for vehicle passenger compartment air conditioning, which has the feedback temperature control signal derived from a sensor disposed to sense the refrigerant temperature at the evaporator inlet and which functions through an algorithm programmed into an electronic controller to maintain the required flow through the evaporator for effective cooling and to prevent evaporator icing. The system computes temperature set points for a given set of blower speed and air blend settings and cycles the compressor when the averaged temperature from the sensor is outside the set points.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of an on-board vehicle refrigeration system;
FIG. 2 is a block logic diagram for the controller of the system of FIG. 1;
FIG. 3 is a flow diagram of the algorithm for the controller of the system of FIG. 1;
FIG. 4 is a graph of temperature set point as a function of the system blower speed for the system of FIG. 1 for recirculation mode of operation; and,
FIG. 5 is a graph similar to FIG. 4 of temperature set point as a function of blower speed for outside air directed over the evaporator for the system of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a typical on-board vehicle refrigerant system, such as employed for the vehicle passenger compartment air conditioning, is illustrated generally at 10 and includes compressor 12 driven by a power source such as an engine driven belt 14 which is connected to the compressor by an electrically operated clutch 16 connected to an electrical controller 18 along leads 20 , 22 . The controller is operated by an on-board vehicle electrical source 24 .
The compressor discharges along line 26 which is connected to the inlet of an exothermic heat exchanger or condenser 28 which discharges along line 30 to a receiver/drier 32 which provides refrigerant flow along line 34 to the inlet of an expander 36 which, in the present practice of the invention, comprises a fluid capsule operated thermal expansion valve as is well known in the art of motor vehicle air conditioning systems. It will be understood however, the present invention may alternatively be employed in a system utilizing a capillary tube or other type expander 36 in place of a thermal expansion valve. The low pressure outlet of the expander 36 is applied along line 38 to the inlet of an endothermic heat exchanger or evaporator 40 . A temperature sensor which may be in the form of a thermistor or temperature transducer 42 is preferably disposed in line 44 at the outlet of evaporator 40 for sensing the temperature of the refrigerant discharging from the evaporator. However, it will be understood that the sensor may alternatively be disposed in the inlet line 38 of evaporator 40 , as shown in dashed outline in FIG. 1 and denoted by reference numeral 42 ′.
The evaporator discharges the superheated refrigerant along line 44 which is passed through the block of expander 36 for heat conduction purposes in a known manner and is returned to the compressor inlet along line 46 .
The controller 18 receives inputs from the user operated blower speed select switch 48 along line 49 and also from the user operated A/C on/off switch 50 and from the temperature sensor 42 along leads 52 , 54 . The controller also receives an input along line 52 from a user temperature select input 55 . The controller 18 also receives an input from the user operated outside air/recirculation mode select control 56 which provides an input along line 58 to the controller and an ambient temperature signal along line 59 from ambient temperature sensor 57 .
Referring to FIG. 2, the general operation of the controller 18 is indicated wherein the refrigerant temperature input T C from the sensor 42 is operative to enable a set point temperature calculation hereinafter described with reference to FIGS. 4 and 5 which the controller utilizes to determine whether the compressor clutch should be engaged or disengaged.
Referring to FIG. 3, the operation of the controller 18 is shown in a flow diagram wherein the system within the controller experiences initiation or Start at step 60 and moves to step 62 to select the sampling rate SR of the decision making and selects the sampling rate sr of data acquisition at step 64 . The system then proceeds to read the inputs ACS, BSS, CCS, CCT, AQS at step 66 where ACS is the air conditioning selection, where zero represents OFF and one represents ON. BSS is the blower speed selection and has values low, M1, M2, M3, and high represented digitally by the integers 1 through 5 . CCS is the compressor clutch status where zero represents the disengaged clutch and one represents the clutch engaged condition. CCS* represents the compressor clutch status at a previous sampling time. CCT is the cold control temperature as measured by the sensor or T c . AQS is the air quality status and is represented by the air flow vane position having a state OSA equals one for outside air flow into the passenger compartment; and, OSA equals zero for air recirculation flow in the passenger compartment.
The system then proceeds to step 68 and asks the question whether BSS is zero; and, if the answer is affirmative returns to Start at step 60 , but if the answer is negative the system proceeds to step 70 and asks the question whether ACS is zero. If the determination at step 70 is affirmative the system returns to Start at step 60 ; but, if the determination in step 70 is negative the system proceeds to step 72 and computes the average refrigerant temperature {overscore (T)}. It will be understood that in the calculations for {overscore (T)}according to the expressions shown in step 72 of FIG. 3, “i” is equal to the number of samples taken at the rate of “sr” of step 64 . The system then proceeds to step 73 and asks if air flow is outside or if OSA equals one. If affirmative the system proceeds to 74 and finds the temperature set points η from a look-up table of values of BSS and AQS from FIG. 5 . If, however, the determination at step 74 is negative, the system proceeds to step 75 and determines the temperature set points η from a look-up table in accordance with FIG. 4. A simplified form of the lookup table is shown in Table I set forth below.
TABLE 1
BSS
Low
M1
M2
M3
High
Outside
Engage ° F.
42
40
38
36
34
Air
(CCS = 1)
(OSA = 1)
Disengage ° F.
38
36
34
32
30
(CCS = 0)
Recirculation
Engage ° F.
44
42
40
38
36
(OSA = 0)
(CCS = 1)
Disengage ° F.
40
38
36
34
32
(CCS = 0)
It will be understood that for each type vehicle, a table of set point values must be predetermined for programming of the controller 18 .
The system having determined the temperature set points η at step 74 or step 75 proceeds to step 76 and asks the question whether the average temperature is equal to or greater than η or less than or equal to η plus an increment δ. If the determination at step 76 is affirmative the system returns to step 60 ; and, if the determination at step 76 is negative the system proceeds to step 78 and asks whether the average temperature {overscore (T )}is equal to or less than the set point η. If the determination at step 78 is negative the system proceeds to step 80 and asks whether the average temperature {overscore (T)}is equal to or greater than η plus δ and if not, the system returns to Start at step 60 . If the determination at step 80 is affirmative the system proceeds to step 82 and asks whether CCS is equal to one, representing the compressor clutch engaged. If the determination at step 82 is affirmative, the system returns to Start at step 60 ; and, if negative the system proceeds to step 84 and engages the compressor clutch by setting CCS equal to one and returns to Start at step 60 .
If the determination at step 78 is affirmative, the system proceeds to step 86 and inquires whether the compressor clutch status is equal to one, and if the determination is negative, the system proceeds to maintain the compressor clutch status at CCS* at step 88 . However, if the determination at step 86 is affirmative the system proceeds to disengage the compressor clutch at step 90 by setting CCS equal to zero and returning to Start at step 60 .
Referring to FIGS. 4 and 5, the temperature set points are plotted graphically as a function of blower speed for the conditions of recirculating air (OSA equals zero) and outside air (OSA equal to one or zero) for the system operating in accordance with the program of FIG. 3 and Table I. It will be observed from FIG. 4, that the value of δ has been set at 4° F. for OSA=0. FIG. 5 shows that for OSA=1, a value of 4° F. has been chosen for δ. It will be understood that decreasing δ increases compressor clutch cycling frequency and improves air temperature stabilization.
The present invention thus provides a technique for controlling the cycling of a compressor clutch for an automotive air conditioning system which minimizes the occurrence of evaporator freezing and the resultant long cycling of the compressor in an effort to provide cooling with the evaporator coated with ice. The present invention provides for optimizing the compressor clutch cycling from measurements of the temperature of the refrigerant discharging from the evaporator and calculating temperature set points based upon knowledge of the system from a lookup table based on user selected blower speed and air mode settings.
Although the invention has hereinabove been described with respect to the illustrated embodiments, it will be understood that the invention is capable of modification and variation and is limited only by the following claims. | A temperature sensor is disposed to sense refrigerant temperature discharging from the evaporator of a vehicle air conditioning system. The temperature is averaged over the sampling interval and is inputted to an electronic controller. The controller computes the temperature set points from a lookup table based upon blower speed and blend door settings and cycles the compressor if the averaged temperature is outside the set points. | 6 |
BACKGROUND OF THE INVENTION
A shell is defined as a curved structural body with a thickness much less than the radius of curvature of the surface. A shell is essentially characterized by its reference surface, its thickness, and its edges. The reference surface defines the overall shape of the shell and it is a principal factor in the structural behavior of the body.
The usually right angled edges of shells are necessarily thicker or at least stronger than the shell surface itself. In this invention, the shell edges are arcs of great circles lying on a spheroidal surface of revolution. Parabolic, spherical or ellipsoidal surfaces can thus be designed using this inventive concept.
The theory of thin shells has been well developed in the classical mathematical and physical mechanics literature. To a first approximation, the important membrane action of shells implies that their resistance to external loads is carried by internal forces induced within the shell surface, analogous to the skin forces of a balloon in resisting internal pressures.
Although shells are well known in nature and in certain artificial structures, such as airplanes, boats and automobiles, they have not gained wide acceptance because of the difficulties in fabricating and erecting these structures. Most large shells have complicated joint connections which are not easily assembled in the field and the specialized plate and beam members are not easily formed and installed. Spherical surfaces have been inherently more difficult to lay out than rectangular shapes compatible with normally available building materials. Large reflectors have usually not been feasible because of weight, structural complexity, aiming problems and wind loads.
It is the purpose of these specifications to describe a novel but simple method of constructing relatively large shells which can be utilized as solar reflectors or as cost efficient buildings. Large solar reflectors hold considerable promise for concentrating solar energy on a small area, perhaps using a movable focal point which for a sphere is located at half the radius of curvature from the reflecting surface. When used either as a reflector or as a domical building, the shell edges also act as edge arches and thus need only be supported at the corners where the edges join one another.
DESCRIPTION OF THE PRIOR ART
Considerable attention has been given to innovations that would hopefully lead to the surmounting of past difficulties in constructing shells.
G. B. Woods (U.S. Pat. No. 2,736,072) proposed the division of the hemisphere into triangular quadrants and each quadrant into three four-sided spherical figures, the latter division being accomplished by drawing lines from the midpoint of the quadrant to the midpoint of each of its three sides. The resulting dividing lines lie along great circle arcs and define the supporting framework. Woods then goes on to describe a method for covering the four-sided spherical area using originally flat sheathing material, the method relying upon the subdivision of the area so as to obtain a flat diamond shaped central area surrounded by four curved isosceles triangles over which a flat sheathing material could be laid and fitted to follow the curvature of the supporting beams.
R. B. Fuller (U.S. Pat. No. 2,905,113) describes a self-strutted geodesic structure in which overlapping rectangular panels are joined along the outlines of a grid of geodesic triangles. The triangles are isosceles, again with the apparent purpose of facilitating the forming of the corners of the panels to the spherical shell surface. Surface coverage is incomplete and the structure has not met with wide industry or public acceptance.
In a later patent (U.S. Pat. No. 3,197,927), Fuller defines sets of pre-formed and pre-shaped elements that may be assembled on the site into geodesic structures.
C. J. Schmidt (U.S. Pat. No. 2,978,074) subdivides a spherical surface by a framework of curved triangles in order to facilitate the covering of the structure with flat sheathing materials. In this case, a spherical pentagon is subdivided by lines from the center to the five corners. These lines define the framework of isosceles triangles which can then be fitted by inserting flat triangular panels. The covering material lies flat over the center of a triangle and follows the curvature of the supporting structure over the edges.
J. S. Sumner, inventor of the present disclosure, discloses in U.S. Pat. No. 4,092,810 a shell surface construction that eliminates the supporting structure entirely and subdivides the spherical surface into scalene triangles. The total frameless structure utilizes a single triangular element in left-hand and right-hand configurations. Two such elements may be readily cut from a single sheet of plywood of standard dimensions with a minimum of waste. The elements or panels overlap at the edges where they are secured together to form great circle arcs, the overlapping edges composing in themselves an integral reinforcing supportive structure.
FIELD OF THE INVENTION
The present invention addresses the problem of constructing shell surfaces using substantially rectangular strips of material in dimensions and proportions that are compatible with those of commercially available building materials. The intent of the invention is to achieve a maximum utilization of the standard materials with a minimum of waste. A further goal is to provide a method that does not restrict its use to any limited range of structure sizes.
From spherical geometry it is known that the great circle of a spheroid has a perpendicular axis, defined as the center diameter normal to the plane of the great circle. In turn, this axis defines families of small circles and planes which are parallel to the great circle. If closely spaced, the parallel planes intersect conical strips on the surface of the reference spheriod. The axis of the cone coincides with the axis of a corresponding great circle edge.
Each curved, great circle edge of a multi-edged shell defines the outer boundary of a radial sector on the shell surface. The radial sectors all have a common interior corner at the shell center. These spherical triangular sectors can be surfaced with concordant strips of covering material, starting along the outer great circle edge and progressing inwardly.
The method provided may permit the construction of the shell as a self-supporting or free-standing form or it may be utilized as a covering over a skeletal spherical surface.
SUMMARY OF THE INVENTION
In accordance with the invention claimed, an improved shell surface construction or covering is provided that utilizes as its basic building block an elongated, substantially rectangular strip. The strips are of constant width and are modified at their ends to trapezoidal form permitting their assembly using joints at the ends and overlapping side joints along the long edges of the strips.
It is, therefore, one object of the present invention to provide an improved shell structure.
Another object of the invention is to provide a means for initially subdividing the spherical surface into spherical triangular sectors that lend themselves to the application of the construction or covering method of the invention.
A further object of the invention is to provide an improved method for further subdividing a spherical triangular sector beyond that realized in geodesic dome construction.
A still further object of the invention is to provide a means for enlarging the overall size of the structure so that large multi-sided shells can be constructed.
A still further object of the invention is to provide a means of construction that can be applied to originally flat strips of material having essentially parallel edges.
A still further object of this invention is to provide a constructional method not requiring a permanent supporting framework or using special erection or assembly tools.
A still further object of this invention is to provide a shell design that is cost-effective in terms of materials and constructional labor.
A still further object of this invention is to permit the realization of heating and cooling efficiencies which may result from domical shell structures and their capabilities for enclosing a maximum volume with a given exposed surface area.
Another object of the invention is to use the fewest number of simple, standard shapes of constructional materials. Yet another object of this invention is to provide a constructional means for taking full advantage of elastic theory as set forth for thin-wall shell structures.
Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may be more readily understood by reference to the accompanying drawing in which:
FIG. 1 illustrates a hemispheroid showing an inscribed uptilted three-edged shell which is further subdivided into three sectors; this three-edged surface constituting the simplest form of the multi-edged shell structure of this invention;
FIG. 2A illustrates the circumscription of a conical surface over the spherical surface and the inscribed three-edged shell of FIG. 1 in conjunction with a means for the constructional subdivision thereof;
FIG. 2B is a partial cross-sectional view of the construction shown in FIG. 2A taken along a plane that passes through the common axis of the sphere and cone of FIG. 2A vertically bisecting the three-edged inscribed shell;
FIG. 2C is an elaboration of FIG. 2B showing in addition thereto a second inscribed conical cross-section of a different length;
FIG. 2D is an enlarged view of a sector of the three-edged shell of FIGS. 1, 2A, 2B and 2C;
FIG. 3 illustrates a conical strip forming a constructional element of a domical shell structure formed by the circumscribed cones of FIGS. 2A-2C;
FIGS. 4A and 4B are detailed perspective views of overlapping and abutting elongated strips employed as the constructional elements or building blocks embodying the invention;
FIG. 4C is a cross-sectional view of the elements of FIGS. 4A and 4B as seen along line 4C--4C of FIG. 4A;
FIGS. 5A, 5B and 5C are plan views of three, four and five-sided domical surfaces constructed in accordance with the principles of the invention;
FIG. 6 is a detailed perspective view of a corner of a multi-edged shell structure in accordance with the construction defined by the invention; and
FIG. 7 is a perspective view of a three-edged shell constructed in accordance with the principles and procedures defined by the disclosed invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring more particularly to the drawing by characters of reference, FIG. 1 illustrates a hemispheroid 10 within which is inscribed a three-edged shell 11. The edges 12, 13 and 14 of shell 11 lie along great circle arcs of sphere 10. Shell 11 is subdivided into sectors 15, 16 and 17 by the bisectors 18, 19 and 20, respectively, of the corners 21, 22 and 23 of shell 11. The intersection of bisectors 18, 19 and 20 defines an apex 24 of shell 11.
With reference to FIGS. 2A, 2B and 2C, a cone or conical surface 25 is circumscribed over spherical sector 15 with the plane of the circle of tangency 26 passing horizontally through sector 15. Cone 25 has an apex 27 and a generating apex angle θ. A radius 28 of hemisphere 10 meets the circle of tangency 26 as shown in FIG. 2B and forms a right angle with the edge 29 of cone 25.
As shown in FIG. 2B, it is important to note that edge 12 and cone 25 have a common axis 31 that is perpendicularly arranged to a reference plane 32. Cone 25 has an overall height 33 with respect to plane 32 and the length of edge 29 of cone 25, i.e., the slant height of cone 25, is equal to the distance between apex 27 and circle 26. Angle φ lies on the surface of cone 25 and angle φ is much less than apex angle θ.
It will be recognized that as the height 33 of cone 25 is increased while maintaining cone 25 tangent to sphere 10, the circle of tangency 26 moves downwardly toward plane 32. This effect is illustrated in FIG. 2C where two cones 25 and 25' having heights 33 and 33', respectively, are shown to intersect hemisphere 10 at circles of tangency 26 and 26', respectively. In an extension of this procedure, a succession of incremental heights 33, 33', 33", etc. will produce a corresponding set of parallel circles 26, 26', 26", etc. passing across the face of sector 15, as shown in FIG. 2D. If the increments of the heights of cone 10 are appropriately chosen, the parallel circles 26, 26', 26", etc. will be equally spaced with a separation W as shown. The lines 26, 26', 26", etc. define the edges of the elongated conical strips described in the present disclosure as the construction elements for the domical surface. One such element 32 is shown in FIG. 2D which has a width W and a length L.
Referring now to FIG. 3 which again shows element 34 positioned between parallel line 26 and 26', the length L is seen to be a maximum dimension for the element which is actually trapezoidal rather than rectangular in configuration. As shown in the enlarged view of FIG. 3, the ends of element 34 are defined by rays 35 and 36 which emanate from the apex 27 of the circumscribed hemisphere employed in the formation of line 26. These rays 35 and 36 subtend the maximum length L of element 34 and define an angle of taper φ/2 to which the ends of the element 34 are to be cut. The taper angle φ/2 is also defined by the end tilt angle of the trapezoidal projection of element 34 onto a circumscribed cylindrical surface (not shown) conforming with the curvature of element 34. The tapered end cuts are made to provide proper mating at the butt-joints between adjacent elements 34 and 34' that are to be aligned end-to-end between the two adjacent lines 26 and 26'. It is readily apparent from FIG. 3 that the taper angle φ/2 is equal to one-half the angle φ that is formed between the rays 35 and 36. This relationship will be employed later in a calculation of taper angles for a specific embodiment of the invention in which element 34 is cut from a two-by-eight foot sheet of plywood or other common construction material. Because the elements 34 have their taper angles φ/2 defined by rays from the apex 27 of cone 25 which has different lengths for different vertical positions over the surface of sector 15, there will be correspondingly different taper angles.
After a set of elements 34 has been thusly defined and cut accordingly to cover surface 15, they are applied to sector 15 as shown in FIG. 5A. An identical set is employed to cover sector 16 and another to cover sector 17. The elements are applied in a manner similar to the application of conventional shingles to a flat roof, beginning with the first course at the lower edge 37 of each of the sectors 15, 16 and 17 and working upwardly, one course at a time, toward the apex 24.
Details of the joining and mating together of the individual elements 34 are shown in FIGS. 4A, 4B, 4C and 6. FIG. 4B shows a butt joint formed between the ends of adjacent elements 34 and 34'. Screws or nails are employed to fasten the abutting ends of the elements to a block 39 which backs up the joint from underneath. As shown in FIG. 4A, successive courses of elements 34 overlap by a small amount 41 to permit the securing together at the overlapped edges by means of nails or screws 38. Glue may be employed as an alternate means for joining or in conjunction with nails or screws for further strengthening and sealing the joint.
At the corners of shell 11 where sectors 15, 16 and 17 meet, the adjoining ends of elements 34 are individually cut to provide a proper fit between corresponding courses of adjoining sectors. FIG. 6 shows a lower corner construction corresponding to corner 23 at the junction of sectors 15 and 17. The lower course is supported by edge arch members 42 which are tied together by means of a metal bracket 43 and screws or bolts 44. The corner of end element 34 of sector 17 is seen to extend into sector 15 where its edge mates with a specially cut end of an element 34' in the corresponding lower course of sector 15. In the second course, end element 34" of sector 15 extends into sector 17 to mate with a specially cut end element 34'" of sector 17. Extensions are alternated in this manner through successive courses.
The curvature of the surface of hemisphere 10 results in a tilting of successive courses of elements 34 with respect to adjacent courses. A means for calculating the relative angular displacement between the surfaces of elements 34 in adjacent courses is derived from the illustration of FIG. 4C which shows an edge view of two adjacent courses and their corresponding elements 34 and 34'. A radius 28 of the hemisphere perpendicularly intersects the center of element 34 and forms an angle θ with surface 32. In the next higher course, the radius 28' perpendicularly intersects the center of the next higher element 34'. The angular displacement between the two radii 28 and 28' is referenced as Δθ and is given (approximately) by the equation Δθ=arc tan W/R where W is the width of element 34 and R is the radius of hemisphere 10. More precisely, Δθ=arc tan Y/R where Y is equal to W diminished by the amount of overlap 41 between successive courses of elements 34.
A method for defining and assembling a three-edged shell 11 has thus been provided in the foregoing description. The same method may be applied to provide the four-sided and five-sided shells 51 and 52 of FIGS. 5B and 5C, respectively. The circumscribed cone constructions are employed in these cases to a quarter-sector 53 of shell 51 and to a one-fifth sector 54 of shell 52.
The validity of the design just described is demonstrated by the calculations summarized in Table I. The calculations for Table I are based on a spherical radius R of 38.2 ft. and on a three-edged inscribed shell surface with an outer edge dimension (arc length) of 60 feet. The elements 34 are assumed to have a width of two feet and an overall length of eight feet. Overlap between successive courses is two inches.
TABLE I______________________________________ Taper Cone Apex Cone Slant Trapezoidal Inches perCourse # Angle θ Height (ft) 0/2 Degrees 2' Width______________________________________1 1.375° 1591.36' 0.14° .062 4.124° 529.64' 0.43° .183 6.875° 316.80' 0.72° .304 9.625° 225.24' 1.02° .435 12.375° 174.09' 1.32° .556 15.125° 141.32' 1.62° .687 17.875° 118.44' 1.96° .828 20.625° 101.49' 2.26° .959 23.375° 88.37' 2.59° 1.0910 26.125° 77.88' 2.94° 1.2311 28.875° 69.27' 3.31° 1.3912 31.625° 62.03' 3.70° 1.5513 34.375° 55.84' 4.11° 1.72Shell Apex 35.264° 54.02' 4.25° 1.78______________________________________
For the first course the cone apex angle θ is defined by: ##EQU1##
Note that for the first course, the radius R' defining θ is drawn to the center of the lowest element 34 so that θ subtends one-half the width W of the element 34 (diminished by the overlap). Hence, tan θ is equal to 0.5(24"-2")/38.2'(12). With each succeeding course, θ is increased by an amount corresponding to Δθ which was earlier shown to be given by: ##EQU2##
From FIG. 2B, it is seen that: ##EQU3##
The cone slant height (column 3) is thus calculated for each course using the values shown in column 2 for θ.
The trapezoidal taper or projection shown in column 4 is calculated from the formula derived earlier on the basis of FIG. 3 which is given as follows: ##EQU4##
Application of the above formula using the slant height values from column 3 yields the corresponding degrees of taper shown in column 4.
Finally, the inches of taper shown in column 5 are calculated from the degrees of taper as follows: ##EQU5##
Application of the above formula using values of φ/2 as shown in column 4 yields the corresponding taper dimensions in inches shown in column 5.
An examination of the tabulated values shown in Table I indicates the following:
First, the relative tilt or angular displacement between successive courses is only 2.75 degrees. An essentially smooth and continuous surface is thus provided across the overlapped courses.
Second, the amount of taper is quite small, beginning at 0.14 degrees at the edge to 4.25 degrees at the apex (0.06 and 1.78 inches, respectively, across the two foot width of the eight foot element 34). This is indicative first of extremely low material waste. At the same time, it suggests that the use of the straight-edged elements 34 to approximate the conical surfaces will produce only minor deviations from the circles of tangency 26.
The success of this herein disclosed sector-and-strip method of shell covering is due to the fact, as shown in Table I, that the shell apex 24 is only 35.3 degrees away from the sector edge and the derived conical curvature of the strips is minimal in comparison to a cylindrical curvature.
Shell surfacing elements must have a certain amount of stiffness and therefore even with an underlying forming surface, these surfacing elements may not readily assume an exact conical shape, but rather the elements may prefer a simple cylindrical curvature. From spherical trigonometry, end taper angles can easily be calculated for great circle cylindrically curved conformal elements. These angles and also the overlap interval between successive course elements are found to be substantially the same as, but slightly less than, those calculated in Table I for the conical shape, the differences always being less than a few percent.
An effective and efficient construction or covering method is thus defined for shell surfaces in accordance with the stated objects of the invention and although but a few embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims. | A method for constructing a multi-edged shell surface using elongated strips of wood or other materials. The positioning of the strips and the shaping of the ends of the strips are defined by a procedure employing circumscribed cones. | 4 |
FIELD OF THE INVENTION
The present invention relates to a demolishing apparatus using discharge impulse for demolishing an object to be demolished, such as concrete or rock mass, by using discharge energy.
BACKGROUND ART
So far, dynamite has been known as demolishing means for demolishing an object to be demolished such as concrete or rock mass, however, a danger is involved in handling the dynamite.
A demolishing apparatus using discharge impulse, which uses discharge energy, has been proposed in recent years as a way of eliminating such danger.
This demolishing apparatus using discharge impulse comprises a pair of electrodes connected to each other by means of a metal wire, and an energy supply circuit being connected to these electrodes and adapted to supply electrical energy to the metal wire, wherein the metal wire is immersed in a demolishing material (a liquid such as water or a semisolid material is used) filled in a demolishing container (hereinafter referred to simply as “container”).
Next, the demolishing method for the aforementioned demolishing apparatus using discharge impulse will be explained. According to the method, the metal wire is immersed in the container filled with a demolishing material, the demolishing container is installed in an installation hole formed in an object to be demolished, the supply circuit is connected to the electrodes, a capacitor installed in this supply circuit is charged with a prescribed quantity of electrical energy, and this electrical energy is supplied to the metal wire for a short time (for example, several dozen μs), that is in other words, electric power is discharged. Whereupon, the metal wire suddenly melts and vaporizes and expands in volume. Following this, the demolishing material also suddenly vaporizes and expands. The volume expansion force of the metal wire is transmitted by this demolishing material, and the sudden volume expansion force of the metal wire and the vaporization and expansion force of the demolishing material act on the walls of the installation hole, for example, in such a manner that the installation hole is pressed outward, thereby demolishing the object to be demolished.
However, with the aforementioned demolishing apparatus, the vaporization and expansion force of the demolishing material filled in the container is used to demolish an object to be demolished, so that resultant physical force such as a shock force cannot be sufficient. Therefore, there are such cases, depending on the kind of object to be demolished, that sufficient demolishing force cannot be obtained, and because of this, further improvement of the demolishing force is desired.
It is an object of the present invention to provide a demolishing apparatus using discharge impulse which is capable of resolving the foregoing problems.
DISCLOSURE OF THE INVENTION
The present invention is a demolishing apparatus using discharge impulse in which electrical energy is supplied for a short time to a melting and vaporizing material (for example, a metal wire is used) placed in a container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein a container is filled with a demolishing material which vaporizes and expands following the melting and vaporizing of the melting and vaporizing material, and a granular material (metal balls, pebbles, ceramic balls or the like are used) which transmits a direct force to the surroundings by a volume expansion force generated when the melting and vaporizing material melts and vaporizes.
According to this invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the volume expansion force generated during the melting and vaporization of the melting and vaporizing material causes the granular material to give a shock to the object to be demolished, thereby demolishing the object without fail.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a container so as to cause the melting and vaporizing material to suddenly vaporize and melt, thereby demolishing an object to be demolished; wherein the container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes and a direct shock force; wherein a synthetic resin or paper, or a metal pipe, is used as a material constituting the container; and wherein a cylindrical holding body made of a hard material and having an opening at least at one end thereof is provided in the container such that the container faces the object to be demolished.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is ejected from the opening at one end of the cylindrical holding body toward the object to be demolished by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes; and wherein the cylindrical container is made of a hard material and includes a soft stopper element provided at an opening at one end of the cylindrical container.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is caused to break the stopper element from the opening at one end of the cylindrical holding body so as to be ejected toward the object to be demolished, by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes, said cylindrical container being made of a hard material; wherein a soft stopper element for holding the demolishing material and granular material is provided at a portion partway toward an opening formed at one end of the cylindrical container; and wherein a space portion is formed between the stopper element and the one end of the cylindrical container.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is caused to break the stopper element to eject itself from the opening at one end of the cylindrical holding body toward the object to be demolished, by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings the force of volume expansion generated when the melting and vaporizing material melts and vaporizes, said cylindrical container being made of a hard material; wherein a soft stopper element for holding the demolishing material and granular material is provided at a portion partway toward an opening formed at one end of the cylindrical container; wherein a space portion is formed between the stopper element and the one end of the cylindrical container; and wherein a portion of the cylindrical container corresponding to the space portion formed between the stopper element and the one end is formed in a conical shape such that the inner diameter of the portion on the opening side is greater than the inner diameter on the stopper element side.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material destroys the stopper element and is ejected, but in a limited ejection range, from the opening at one end of the cylindrical holding body toward the object to be demolished, by the volume expansion force generated during the melting and vaporizing of the melting and vaporizing material, thereby demolishing the object to be demolished reliably by the strong demolishing force.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the container is filled with an inflammable demolishing material which burns and vaporizes following the melting and vaporization of the melting and vaporizing material.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes and expands in volume when electrical energy is supplied to the melting and vaporizing material; following this, the inflammable demolishing material burns and vaporizes; and the burning and vaporizing force of the demolishing material acts, with a time lag, on cracks caused by the volume expansion force of the melting and vaporizing material, thereby reliably demolishing the object to be demolished in such a manner as to expand the cracks outward.
Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the container is filled with an inflammable demolishing material which burns and vaporizes following the melting and vaporization of the melting and vaporizing material, and a stable material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, in such a condition that the inflammable demolishing material and the stable material are separated from each other; and wherein the melting and vaporizing material is immersed in both the inflammable demolishing material and the stable demolishing material.
According to this constitution of the invention, the melting and vaporizing material melts and vaporizes and expands in volume when electrical energy is supplied to the melting and vaporizing material; following this, the stable demolishing material vaporizes and expands and causes cracks in the object to be demolished; with a slight time delay from the volume expansion of the melting and vaporizing material and from the vaporization and expansion of the stable demolishing material, the inflammable demolishing material burns and vaporizes; and the burning and vaporizing force of the demolishing material acts on the cracks, thereby reliably demolishing the object to be demolished in such a manner as to expand the cracks outward.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the first embodiment of the present invention;
FIG. 2 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the second embodiment of the present invention;
FIG. 3 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the third embodiment of the present invention;
FIG. 4 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the fourth embodiment of the present invention;
FIG. 5 is a cross section showing the constitution of a demolishing apparatus using discharge impulse according to the fifth embodiment of the present invention;
FIG. 6 is a cross section showing the installed state of the demolishing apparatus using discharge impulse in an object to be demolished according to the fifth embodiment of the present invention;
FIG. 7 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention;
FIG. 8 is a plan view showing the installed state before demolition of the demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention;
FIG. 9 is a plan view showing the state during demolition of the demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention;
FIG. 10 is a plan view showing the completed state of demolition of the object to be demolished for the demolishing apparatus using discharge impulse showing the sixth embodiment of the present invention;
FIG. 11 is a graph showing the relationship between the passage of time and expansion force in the demolishing apparatus using discharge impulse according to the sixth embodiment of the present invention; and
FIG. 12 is a cross section showing the constitution of a demolishing apparatus using discharge impulse according to the seventh embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is explained in more detail with reference to the appended figures.
The first embodiment for implementing the present invention is explained on the basis of FIG. 1. A demolishing apparatus using discharge impulse 1 in this first embodiment comprises: a bottomed cylindrical or pouch-shaped demolishing container (hereinafter, simply referred to as “container”) 4 inserted in an installation hole 3 formed in an object to be demolished 2 ; a pair of electrodes (or conductive wires) 5 inserted in this container 4 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum) 6 connecting the end portions of these electrodes (or conductive wires) 5 ; a demolishing material 7 and a granular material 8 filled in this container 4 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of said pair of electrodes 5 by means of electrical wiring 9 .
The electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged into the capacitor to the metal wire 6 so as to effect discharge. Also the container 4 is formed of a soft material such as synthetic resin or an elastic material such as rubber. Furthermore, used as the demolishing material 7 is a solid or semisolid material, for example, and to be more specific, it is mortar, mud, silicone, or gel. Used as the granular material 8 is metal balls, pebbles, or ceramic hard balls, for example.
In the case of demolishing an object to be demolished, or concrete 2 for example, using said demolishing apparatus using discharge impulse 1 , an installation hole 3 is formed in a to-be-demolished portion of said concrete 2 , then the container 4 , which has the metal wire 6 inserted thereinto, the demolishing material 7 and the granular material 8 filled therein, and a cover element 10 affixed to an opening at the upper end thereof, is inserted into the installation hole 3 . Next, the electrical energy supplying device is connected through the electrical wiring 9 .
Then a discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire 6 for a short time. Whereupon the metal wire 6 suddenly melts and vaporizes. Following this, the demolishing material 7 also vaporizes and transmits the volume expansion force of the metal wire 6 to the concrete 2 , such that the volume expansion force, in combination with the vaporization and expansion force of the demolishing material 7 , forms a demolishing force and demolishes the concrete 2 .
Since the granular material 8 , such as metal balls, is mixed in the demolishing material 7 , the granular material 8 also flies apart into the surroundings with extremely strong force caused by the volume expansion force of the metal wire 6 , whereby the concrete 2 is demolished reliably.
In this way, since a lot of granular material 8 is mixed in the demolishing material 7 , the volume expansion force of the metal wire 6 can be efficiently transmitted to the surroundings.
Next, the second embodiment for implementing the present invention is explained on the basis of FIG. 2 . The demolishing apparatus using discharge impulse 12 in this second embodiment comprises: a cylindrical container 13 having an opening at both upper and lower ends; a stopper element 14 affixed to the opening at the lower end of the cylindrical container 13 ; a pair of electrodes 15 inserted in the cylindrical container 13 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum) 16 connecting the end portions of the electrodes 15 ; a demolishing material 17 and a granular material 18 for filling the cylindrical container 13 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of the pair of electrodes 15 through electrical wiring 19 .
The electrical energy supplying device comprises: a charger, such as a capacitor, which accumulates high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrodes 15 so as to effect discharge.
Also, the cylindrical container 13 is formed of a hard material such as metal, and the stopper element 14 is formed of a soft material such as thin resin film (wrapping film) used for storing food, vinyl, paper, rubber, thin metal plate or the like. In other words, the stopper element 14 is provided simply to prevent the granular material 18 filled in the cylindrical container 13 from escaping to the outside, and can easily be broken when the volume of the metal wire 16 expands. If the demolishing material 17 is in the solid form such as a gel, the stopper element 14 need not be installed.
Further, like in the first embodiment, a solid or semisolid material, for example, is used as the demolishing material 17 . To be more specific, it is mortar, mud, silicone, or gel. And, metal balls, pebbles, or ceramic balls, for example, are used as the granular material 18 .
In order to demolish an object to be demolished, for example concrete 20 , by using the foregoing demolishing apparatus using discharge impulse 12 , a cylindrical container 13 which has a stopper element 14 attached to the opening at the lower end thereof, a metal wire 16 placed therein, a demolishing material 17 and a granular material 18 both filled therein, and a cover element 21 affixed to the opening at the upper end thereof, is placed on a to-be-demolished portion of the concrete 20 . Then, an electrical energy supplying device is connected through electrical wiring 19 .
Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire 16 in a short time. Whereupon the metal wire 16 suddenly melts and vaporizes. Following this, the demolishing material 17 also vaporizes and transmits the volume expansion force of the metal wire 16 to the concrete 20 , said volume expansion force combining with the vaporization and expansion force of the demolishing material 17 to form a demolishing force, thereby demolishing the concrete 20 .
Since the granular material 8 , such as metal balls, is mixed in the demolishing material 7 , the granular material 8 also flies apart into the surroundings with extremely strong force due to the volume expansion force of the metal wire 6 , whereby the concrete 2 is demolished reliably.
Also the granular material 18 mixed in the cylindrical container 13 is filled to a height of half that of the demolishing material 17 , for example. Because the granular material 18 is positioned on the side toward the opening in the lower end in the cylindrical container 13 , the portion above the granular material 18 functions as a pressure producing portion with only the metal wire 16 placed in the demolishing material 17 .
Consequently, during the melting and vaporization of the metal wire 16 , the granular material 18 , positioned on the side toward the opening in the lower end in the container 13 , breaks through the stopper element 14 from the cylindrical container 13 like a shotgun shell and is discharged all at once toward the concrete 20 , whereby the demolishing force is concentrated by the granular material 18 and the concrete 20 is demolished reliably.
Next, the third embodiment for implementing the present invention is explained on the basis of FIG. 3 . This demolishing apparatus using discharge impulse 23 in this third embodiment has about the same constitution as the above mentioned second embodiment. The same symbols are applied to the same elements and a detailed explanation thereof is omitted.
In other words, as shown in FIG. 3, an extension portion 13 a is formed which extends straight just from the cylindrical container 13 below a stopper element 14 provided at the lower end of the cylindrical container 13 in the second embodiment.
With this constitution, when an object to be demolished, such as concrete 20 , is about to be demolished, the opening on the lower end of the extension portion 13 a of the cylindrical container 13 having the metal wire 16 , demolishing material 17 , and granular material 18 placed therein, is held in the state of being pressed against a to-be-demolished portion of the concrete 20 , and electrical energy is supplied to the metal wire 16 , whereby the demolishing material 17 and granular material 18 together are ejected toward the concrete 20 , with the volume expansion force of the metal wire 16 , thereby demolishing the concrete 2 . At this time, the straight extension portion 13 a of the cylindrical container 13 plays the role of a barrel and guides a large number of granules of the granular material 18 in the same direction, thereby increasing the demolishing force to be even stronger.
Next, the fourth embodiment for implementing the present invention is explained on the basis of FIG. 4 . In the demolishing apparatus using discharge impulse 23 in the above mentioned third embodiment, the downward extension portion 13 a of the cylindrical container 13 was straight in form. However, in the demolishing apparatus using discharge impulse 25 according the fourth embodiment, the extension portion is formed in a conical shape such that the inner diameter of the opening on the lower end of the cylindrical container 13 is greater than the inner diameter of the portion where the stopper element 14 is provided.
In addition to the effects obtained from the demolishing apparatus using discharge impulse 23 according to the third embodiment, this constitution allows it to control the volume expansion force of the metal wire 16 and the range of ejection of the granular material 18 , which become the demolishing force during the melting and vaporization of the metal wire 16 .
Next, the fifth embodiment for implementing the present invention is explained on the basis of FIGS. 5 and 6. The demolishing apparatus using discharge impulse 27 according to the fifth embodiment comprises: a cylindrical or pouch-shaped demolishing container (hereinafter referred to simply as “container”) 28 having a bottom; a pair of electrodes (or conductive wires) 29 inserted in the container 28 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum) 30 connecting the end portions of the electrodes 29 ; a demolishing material 31 and granular material 32 filling the container 28 ; a cylindrical holding body 34 which holds the container 28 being filled with the electrodes 29 , demolishing material 31 and granular material 32 and having a cover element 33 fixed in the opening at the upper end thereof, and which has an opening at both upper and lower ends thereof; a cover body 35 screwed onto the opening at the upper end of the cylindrical holding body 34 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy in a short time to the base portions of the pair of electrodes 29 through electrical wiring 36 . Moreover, a hole portion 35 a is formed in the cover body 35 so as to allow passage of the electrodes 29 .
The electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply electrical energy charged in the capacitor to the pair of electrodes 29 so as to effect discharge.
The container 28 is formed of an elastic material such as rubber or a soft material such as synthetic resin. Further, a solid or semisolid material, for example, is used as the demolishing material 31 , more specifically, it is mortar, mud, silicone or gel, and metal balls, pebbles or ceramic balls, for example, are used as the granular material 32 .
When an object to be demolished, such as concrete 37 , is demolished using the foregoing demolishing apparatus using discharge impulse 27 , the cover element 33 is fixed in the opening portion at the upper end of the container 28 filled with the metal wire 30 , demolishing material 31 and granular material 32 , as shown in FIG. 5, and subsequently, as shown in FIG. 6, the container 28 is inserted in the cylindrical holding body 34 in such a manner as to face the concrete 37 by being held by a ring-shaped protruding portion (the protruding portion may simply consists of a plurality of protrusions provided at a plurality of locations) 34 a protruding at a prescribed location inside the cylindrical holding body 34 . Thereafter the cover body 35 is screwed onto the opening at the upper end to hold the entire container 28 .
The cylindrical holding body 34 holding the container 28 is placed to be pressed against a to-be-demolished portion of the concrete 37 . As electrical energy is supplied to the metal wire 30 in this state, powerful demolition can be effected in the same way as in the third embodiment.
Next, the sixth embodiment for implementing the present invention is explained on the basis of FIGS. 7 through 11. The demolishing apparatus using discharge impulse 40 in this sixth embodiment comprises: a cylindrical or pouch-shaped container 43 having a bottom and being inserted in an installation hole 42 formed in an object to be demolished 41 ; a pair of electrical wires (electrodes) 44 inserted in this container 43 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum) 45 connecting the end portions of the electrical wires 44 ; a demolishing material 46 filling the container 43 ; a cover element 47 to seal this demolishing material 46 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of the pair of electrical wires 44 through electrical wiring 48 .
The foregoing metal wire 45 is immersed in the demolishing material 46 , said demolishing material 46 being composed of an inflammable material such as thinner or kerosene, or an explosive material.
The foregoing electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrical wires 44 so as to effect discharge.
When an object to be demolished, such as a concrete 41 , is demolished using the foregoing demolishing apparatus using discharge impulse 40 , the container 43 is filled with the demolishing material 46 , the demolishing material 46 is sealed with the cover element 47 which the electrical wires 44 pass through, the container 43 is inserted in the installation hole 42 formed in the concrete, the installation hole 42 is filled with tamping material 50 such as sand, and the electrical energy supplying device is connected to the metal wire 45 through the electrical wiring 48 .
Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire 45 for a short time. Whereupon the metal wire 45 suddenly melts and vaporizes. Following this, the demolishing material 46 also burns and vaporizes (explodes) together and transmits the volume expansion force of the metal wire 45 to the concrete 41 , said volume expansion force combining with the vaporization and expansion force of the demolishing material 47 to form a demolishing force, thereby demolishing the concrete 20 .
Here is an explanation of the sequence in which the concrete 41 is demolished. With the volume expansion force generated during the melting and vaporization of the metal wire 45 , a plurality of cracks 51 occur around the installation hole 42 as shown in FIG. 9 . Subsequently, after a passage of a small period of time t, the demolishing material 46 burns and vaporizes, and the force of vaporization and expansion thereof acts on the cracks 51 and expands these cracks 51 outward, as shown in FIG. 10, thereby destroying the concrete 41 .
FIG. 11 is a graph in which the horizontal axis represents the passage of time since the supply of electrical energy and the vertical axis the vaporization and expansion force of the metal wire at the time of volume expansion thereof. The solid line A shows the case where the metal wire 45 suddenly melts and vaporizes, and the broken line B shows how the vaporization and expansion force produced when the demolishing material 46 burns and vaporizes acts on each crack 51 . It is known from this graph that the vaporization and expansion force of the demolishing material 46 acts gradually on each crack 51 in the object to be demolished 41 .
In the above mentioned sixth embodiment, an inflammable material or explosive material is used as the demolishing material 46 to be filled in the container 43 . As a result, the vaporization and expansion force of the demolishing material 46 acts gradually on the plurality of cracks 51 caused to occur by the volume expansion force of the metal wire 45 , and the cracks 51 are expanded outward, whereby the concrete 41 is demolished reliably.
Next, the seventh embodiment for implementing the present invention is explained on the basis of FIG. 12 . In the demolishing apparatus using discharge impulse 55 according to the seventh embodiment, the demolishing material 56 comprises a stable material 57 in the form of a gel and an inflammable material 58 in the form Qf a liquid, said stable material 57 and inflammable material 58 being separated in the container 50 , and a metal wire 60 is immersed in both of the stable material 57 and the inflammable material 58 .
A cover element 61 to seal the demolishing material 56 is installed on the container 62 , and an electrical energy supplying device (not depicted) for supplying high voltage electrical energy for a short time to the metal wire 60 is connected to the base portions of a pair of electrical wires (electrodes) 63 . Also, the metal wire 60 is made to expose itself by removing part of a covering element 64 of the electrical wires 63 partway.
The foregoing electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrical wires 63 so as to effect discharge.
When an object to be demolished is demolished using the foregoing demolishing apparatus using discharge impulse 40 , the container 62 is filled with the demolishing material 56 , the demolishing material 56 is sealed with the cover element 61 which the electrical wires 63 pass through, the container 62 is inserted in the installation hole formed in the object to be demolished, the installation hole is filled with a tamping material such as sand, and the electrical energy supplying device is connected to the metal wire 60 through the electrical wiring 63 .
Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire 60 for a short time. Whereupon the metal wire 60 suddenly melts and vaporizes. Following this, the stable material 57 vaporizes and the inflammable material 58 also burns and vaporizes, thereby transmitting the volume expansion force of the metal wire 60 to the object to be demolished, and the volume expansion force of the metal wire 60 combines with the vaporization and expansion force of the demolishing material 56 so as to form a demolishing force to the effect of demolishing the object to be demolished.
Here is an explanation of the sequence in which the object to be demolished is demolished. With the volume expansion force generated during the melting and vaporization of the metal wire 60 , the stable material 57 vaporizes and the volume expansion force of the metal wire 60 is transmitted, and a plurality of cracks occur around the installation hole. Subsequently, after a passage of a small period of time t, the inflammable material 58 also burns and vaporizes, and the vaporization and expansion force thereof acts on the cracks to expand these cracks outward, thereby demolishing the object to be demolished reliably.
INDUSTRIAL APPLICABILITY
As discussed above, the demolishing apparatus using discharge impulse relating to the present invention can be advantageously used in the case of demolishing an object to be demolished that requires a great demolishing force. | An apparatus which is constituted to supply electrical energy to a melting and vaporizing material (for example metal wire 6 ) so as to cause the melting and vaporizing material to melt and vaporize, thereby demolishing an object to be demolished (such as concrete 2 ) using the vaporization and expansion force generated at the time of melting and vaporization of the material; wherein either by providing a granular material 8 which ejects from a container following the generation of the vaporization and expansion force, or by using an inflammable material as demolishing material 46 in which the melting and vaporizing material is immersed, a to-be-demolished object is demolished with a strong demolishing force. | 4 |
BACKGROUND TO THE INVENTION
This invention relates to jet assemblies and has particular reference to such assemblies for the spinning of cellulose filaments from a solution of cellulose in a suitable solvent.
Cellulose may be dissolved in a tertiary amine oxide, for example by the method described in U.S. Pat. No. 4,246,221, the contents of which are incorporated herein by way of reference. Once the cellulose has been dissolved in the solvent, cellulose filaments can be prepared by spinning the solution, commonly referred to as a dope, through a spinnerette into a water bath via an air gap. The cellulose solution is processed at an elevated temperature--typically about 100° C. to 110° C.--and is supplied in the heated condition to the spinnerette for spinning purposes.
The cellulose solution is viscous and has to be pressurised to very high pressure levels--typically 100 to 200 bar for pumping purposes. The use of such high pressures means that the jet assemblies used to spin such solutions experience (as a result of pressure drops in the dope supply system) operating pressures of 30-50 bar. Even higher pressures can be experiences by the jet assembly during start up when the dope is cooler, and hence more viscous. Thus the assemblies have to be of a substantial construction, particularly if they are large and hence the forces involved are large. The jets must in practice be capable of withstanding these forces.
When producing cellulose for use as staple fibre, it is economically essential to produce large numbers of cellulose filaments simultaneously. This inevitably means that the spinning jet assemblies have to be relatively large and, therefore, the forces exerted by the pressurised cellulose become very high. It is necessary to use jet assemblies which can withstand such high forces.
SUMMARY OF THE INVENTION
By the present invention there is provided a jet assembly for the vertically downward spinning of cellulose fibres from a solution of cellulose in a solvent, the jet assembly including:
(i) a rectangular spinnerette including a vertically oriented outer wall having at its upper end an outwardly extending flange:
(a) said outer wall defining an internal space,
(b) at least one vertically oriented internal brace within said internal space to define a plurality of vertically extending apertures through the spinnerette,
(c) a plurality of aperture plates welded into he bottom of the apertures, said aperture plates each having a plurality of spinning holes therethrough, said aperture plates each being welded around their entire periphery,
(d) the lower faces of said aperture plates said at least one internal braces and said outer wall lying in a single horizontal plane.
(ii) a bottom housing having a portion lying below said outwardly directed flange of said spinnerette.
(iii) a top housing defining a chamber for the containment and passage of the solution into the spinnerette the top housing having a downwardly facing annular clamping surface.
(iv) a filter support extending across the top of the spinnerette and having a plurality of holes therethrough for the passage of solution from the chamber into the spinnerette.
(vii) a filter positioned above the filter support and supported by the filter support.
(viii) annular gasket seals between the periphery of filter support and the outer upper face of the spinnerette.
(ix) clamping means to clamp together the top and bottom housings to clamp the flange of the spinnerette and the filter therebetween.
(x) surrounding the lower portion of the spinnerette on at least one longer side and on part at least of the two shorter sides a layer of thermally insulating material extending across part at least of the lower face of the bottom housing and extending over part at least of the lower face of the spinnerette formed by the frame.
The present invention also provides a jet assembly for the spinning of cellulose fibres in a vertically downwards direction from a solution of cellulose in a solvent, the jet assembly comprising:
(i) a spinnerette of generally rectangular shape and having an outwardly directed flange at its upper end, the spinnerette having a lower face having a planar central region with spinning holes therethrough and surrounding the planar central region a lower peripheral region not containing spinning holes,
(ii) a top housing having at its upper end an aperture to receive a supply of cellulose in a solution and an annular lower clamping face.
(iii) a bottom metal housing having an upwardly directed clamping face.
(iv) means to clamp the top and bottom housings together to seal the spinnerette to the top housing.
(v) an annular thermally insulating layer having a thermal conductivity lower than that of the bottom housing, the thermally insulating layer extending across the bottom housing and across at least part of at least an outer portion of the lower peripheral region of the spinnerette.
The present invention further provides a jet assembly for the spinning of a solution of cellulose in an amine oxide solvent, the jet assembly comprising:
(i) a spinnerette:
(a) having a horizontal lower face,
(b) a plurality of spinning holes in said horizontal lower face,
(c) upwardly directed metal walls around the periphery of said lower face,
(d) said upwardly extending walls defining an internal chamber for the passage of said solution therethrough,
(ii) A supply line for the supply of said solution to said spinnerette,
(iii) an upper housing interconnecting said supply line and said spinnerette,
(iv) means to interconnect said spinnerette and said upper housing,
(v) thermally insulating material surrounding some at least of said spinnerette and insulating part at least of the lower edge and lower face of said spinnerette.
BRIEF DESCRIPTION OF THE DRAWINGS
By way of example, embodiments of the present invention will now be described with reference to the accompanying drawings, of which
FIG. 1 is a cross sectional view along a minor axis of a jet assembly,
FIG. 2 is a cross section of a portion of FIG. 1 perpendicular to the section of FIG. 1,
FIG. 3 is a perspective view of a spinnerette, and
FIG. 4 is an underneath plan view of the spinnerette and insulation.
DESCRIPTION OF THE INVENTION
Referring to FIG. 1, this shows a jet assembly located within an insulating cover 1 and frame 2. The frame 2 is thermally insulated from its steel support structure, and has a bore 3 extending around the frame through which a suitable heating medium such as hot water, steam, or oil, can be passed to heat the lower end of the frame. Because the cellulose solution spun through the jet assembly is supplied to the jet assembly at an elevated temperature, typically 105° C., it is preferable to provide heating to maintain the solution at the correct temperature and to provide insulation to minimise excessive heat loss and to prevent injury to operating personnel.
Bolted to the frame 2 by means of bolts or studs 4, 5 is a top housing 6. The top housing forms an upper distribution chamber 7 into which is directed an inlet feed pipe 8. The inlet feedpipe is provided with an O-ring seal 9 and a flange 10. A locking ring 11 is bolted to the upper face 12 of the top housing 6 to trap the flange 10 to hold the inlet feedpipe on the top housing. Suitable bolts or studs 13, 14 are provided to bolt the ring 11 to the top housing 6.
Bolted to the underside of the top housing 6 is a bottom housing 20. A series of bolts 21, 22 are used to bolt the top and bottom housing together and an annular spacer 23 forms a positive stop to locate the top and bottom housings together at a predefined distance.
The bottom housing 20 has an inwardly directing flange portion 24 which has an annular upwardly directed surface 25. The upper housing 6 has an annular downwardly directing horizontal clamping face 26.
Clamped between the faces 25 and 26 is a spinnerette, a breaker plate and filter assembly. The spinnerette, shown in perspective view in FIG. 3, essentially comprises a rectangular member in plan view, having a top hat cross section and comprising an upwardly directed peripheral wall generally indicated by 28 incorporating an integral outwardly directed flange portion 29. The spinnerette incorporates a plurality of aperture plates 30, 31, 32 which contain the holes through which the solution of cellulose in amine oxide, 33 is spun or extruded to form the filaments 34.
The spinnerette construction is more clearly shown and illustrated in our co-pending patent application Ser. No. 08/066,779 PA.RCS 1-93--filed on May 24, 1993.
Located on the upper surface of the flange 29 is a gasket 35. Located on top of the gasket 35 is a breaker plate 36 which essentially comprises an apertured plate used to support a filter element 37. The filter element 37 is formed of sintered metal, and if the sintered metal has a fine pore size, the pressure drop across the filter can, in use, rupture the filter. The breaker plate 36, therefore, supports the filter in use. A pair of gaskets 38, 39 on either side of the filter completes the assembly located between the upwardly directed face 25 of the bottom housing and the downwardly directed face 26 of the top housing. By clamping the assembly together with the bolt 21, 22, the spinnerette, breaker plate and filter are held positively in position.
Located beneath the bottom housing 20 is an annular insulating ring 40 which is generally rectangular in plan shape. The annular insulating ring extends around the complete periphery of the wall 28, which wall 28 extends below the lower face 41 of the bottom housing 20. On one long side of the spinnerette, there is provided an integral extension portion 42 of the insulating ring 40 which extends below the long wall portion 43 of the peripheral wall 28. On the other long wall portion 44 of the peripheral wall 28 the insulating ring 40 does not have the integral extension portion 42, but the lower face 44 of the portion 45 of the ring 40 is in the same plane as the face 46 of the portion 41 of the peripheral wall 28 of the spinnerette.
As is more easily seen in FIG. 2, the insulating ring 40 which is secured to the underside of the bottom housing 20 by screws (not shown) has the integral extension portions 50, 51 extending over the lower faces of the portions 52, 53 of the shorter lengths of the peripheral wall 28 of the spinnerette.
Referring to FIG. 3 this shows in perspective the spinnerette incorporated into the jet assembly. The spinnerette, generally 60, has an outer flange 29 integral with the wall 28. The rectangular nature of the spinnerette can clearly be seen from the perspective view in FIG. 3. The minor axis of the spinnerette is shown in the sectional view of FIG. 1 and the major axis is shown in sectional view in FIG. 2. Welded into the bottom of the spinnerette are six aperture plates 61 which three of the plates 30, 31, 32 seen in sectional view figure of FIG. 1. These plates contain the actual holes through which the cellulose solution is extruded. The spinnerette has an underside in a single plane and is capable of withstanding the high extrusion pressures experiences in spinning a hot cellulose solution in amine oxide.
FIG. 4, is an underneath view of the spinnerette showing the location of the insulating annular member 40. It can be seen that the insulating layer, typically formed of a resin impregnated paper material such as Tufnol (trade mark) extends below the lower portion of the peripheral wall 28 on three sides of the spinnerette. Thus, seen from below, on sides 62, 63 and 64, the lower portion of the wall 28 is obscured by the extension portions in the insulating layer shown as 42, 50a and 51 in FIGS. 1 and 2. However, on the fourth side, side 65, the lower portion 66 of the wall 28 of the spinnerette 60 is not insulated and is, therefore exposed. The insulating annulus, therefore, is effectively surrounding the spinnerette completely and extends on three sides beneath the peripheral wall of the wall of the spinnerette.
It will be noted that the breaker plate 36 has tapered holes 67 which enhance the flow of viscous cellulose solution through the jet assembly whilst providing a good support for the filter 32. In turn the breaker plate 31 is supported by the upper edges of the internal bracing members or spars 68, 69, 70. The upper edges of the internal bracing members or spars may be displaced from the centre line of the members or spars so that the entrance area above each aperture plate is equal.
The facings 25, 26 of the housing and/or the breaker plate 36 may be provided with small recesses such as recess 80 so as to permit the gasket to be extruded into the recess to enhance sealing when the bolts holding the top and the bottom housing together are tightened. An O-ring 84 may be provided between the top and bottom housing to act as a second seal in the event of failure of the main seals between the top and bottom housing and the breaker plate and filter assembly.
The jet assembly of the invention is, therefore, capable of handling highly viscous high pressure cellulose solution in which typically the pressure of the solution upstream of the filter may be in the range 50 to 200 bar and the pressure at the jet face may be in the range 20 to 100 bar. The filter itself contributes to a significant amount of pressure drop through the system whilst in operation.
The assembly of the invention also provides a suitable heat path whereby the temperature of the dope in the jet can be maintained close to the ideal temperature for spinning for extrusion purposes. The bottom housing 20 is in firm positive contact with the spinnerette through its annular upwardly directed face 25. The bolts or set screws 22 ensure a firm positive contact. Similarly, the bolts 4,5 positively ensure that the bottom housing 20 is held tightly to the frame member 22 via its downwardly directed face 81 on an outwardly directed flange portion 82. The face 81 is in positive contact with the upwardly directed face 83 of the housing 2.
By providing a heating element in the form of a heating tube 3 directly below the face 83 there is a direct flow path for heat from the heating medium in the bore 3 into the spinnerette. It can be seen that heat can flow through the faces 83, 81 which, as mentioned above, are held into positive contact by set screws 4, 5. Heat can then flow through the bottom housing 20 via the face 25 and flange 29 into the spinnerette wall 28.
It will readily be appreciated that assemblies of the type illustrated in the drawings of the present application are normally assembled in an ambient temperature workshop. Thus typically the top and bottom housing, the spinnerette, the breaker plate and filter plate assembly will be bolted up at ambient temperature by bolting down the screws 21, 22. To enable the spinnerette to be inserted into the bottom housing 20 there needs to be a sufficient gap between the peripheral wall 28 and the interior hole of the bottom housing 20 which permits the spinnerette to be inserted and removed. It will also be appreciated that in use the assembly is heated to typically 100° C. The combination of heating and internal pressure means that there will be an unregulated expansion of the assembly. All of this means that it is not possible to rely upon a direct heat transfer sideways from the lower portion of the bottom housing directly horizontally into the side of the peripheral wall 28.
Similar constraints apply to the direct horizontal transfer into the outer side wall of the bottom housing 20 directly from the heated lower portion of the frame 2. However, by providing for a positive clamped face-to-face surface such as surface 81, 83, a positive route for the transfer of heat from the medium within bore 3 to the spinnerette is provided. Any suitable heating medium such as hot water, steam or heated oil can be passed through the bore 3.
The provision of the lower insulation 40 whilst not needed from a safety to personnel view point ensures that the heat from the hot cellulose solution itself is passed into the jet assembly from the bore 3 and does not escape through the lower face of the bottom housing.
It will readily be appreciated that the components of the jet assembly should be manufactured from material capable of withstanding any solvent solution passed through it. Thus, for example, the jet may be made from stainless steel and the housings may be made from stainless steel or castings of cast iron as appropriate. The gaskets may be formed of PTFE. | A jet assembly for spinning cellulose fibres from a solution of cellulose in an amine oxide solvent in which the jet assembly includes a generally top-hat shaped spinnerette having a series of downwardly directed holes through the base of the spinnerette and an outwardly directed flange around the periphery of the vertical walls of the spinnerette, the jet assembly including a heated housing engaging with the flange and being bolted to the flange, insulation being provided on the underside of the jet assembly over the outer periphery, the combination of heating and insulation regulating the temperature of the jet assembly for optimum spinning of an amine oxide cellulose solution. | 3 |
This is a continuation of application Ser. No. 902,629, filed May 4, 1978, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates generally to antennas, and more particularly, to slot array antennas.
In the past slot array antennas have generally been designed by using certain design conventions. These conventions included spacing the slots at equal distances and terminating the antenna in either a shorted termination or in the characteristic impedance of the waveguide. However these conventions have several inherent undesirable effects. For example, the phase at each slot is only approximated, the input impedance of the array is generally uncontrolled and therefore usually does not match the impedance of the source, the pattern shapes obtainable from these slot array antennas is limited, and finally, in the case of nonresonant slot array antennas, the antenna must have a large number of slots in order to approximate an impedance match with a generating source.
Therefore, it can be appreciated that a slot array antenna which provides substantially complete control of the phase and amplitude at each slot, provides a match to the generating source, and can be of relatively short length is highly desirable.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a slot array antenna fabrication method which has substantial control of the phase at each slot radiator.
It is also an object of this invention to provide a slot array antenna which can be designed to realize a large variety of antenna patterns.
It is still another object of this invention to provide a slot array antenna which provides a matching impedance to a generating source.
It is also an object of this invention to provide a slot array antenna which is relatively short in length.
This invention in its broadest sense is a slot array antenna. For example, a slot array antenna according to this invention comprises a portion of a waveguide and a plurality of slots disposed in the waveguide wherein the slots are positioned to produce a predetermined and unequal phase relationship between adjacent slots.
Also disclosed is a method for producing a slot array antenna which comprises the steps of providing a portion of a waveguide and forming a plurality of unequally spaced slots in the waveguide where the slots are located so as to substantially produce a predetermined antenna pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing of a desired antenna power pattern in polar coordinates.
FIG. 2 is a plot of the antenna pattern of FIG. 1 showing the E field variation versus the elevation angle.
FIG. 3 is a graphical representation of the slotted array antenna.
FIG. 4 is an equivalent circuit representation of a portion of the slot array antenna.
FIG. 5 is a circuit equivalent representation of a parallel slot array antenna in the broad wall of the waveguide or an equivalent representation of an angled slot array antenna in the narrow wall.
FIG. 6 is an equivalent circuit representation of an angled slot array antenna in the broad wall.
FIG. 7 is a drawing of a completed parallel slot array antenna in the broad wall.
FIG. 8 is a drawing of a completed angled slot array antenna in the broad wall.
FIG. 9 is a drawing of a completed slot array antenna in the narrow wall.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring to FIG. 1, a slot array antenna 10 is positioned vertically above a ground surface 12 and has desired power pattern shown by curve 14. A horizontal line 16 is used as a reference for determining angles, depicted by φ, of components of the desired antenna pattern. In operation a desired slot array antenna 10 is to produce a desired pattern shown as curve 14 onto a ground surface 12. The strength of the antenna pattern is referenced to the angular displacement of each of the components of the pattern with respect to horizontal reference line 16.
FIG. 2 is a plot of the desired E field of the antenna pattern 14 of FIG. 1 versus the angle φ. In a portion 18 of curve 14 the desired antenna pattern approximates a cosecant function. A series of dotted lines 20 depict sample points used to digitize the desired antenna pattern 14 for use in a digital computer.
A representation of the slot array antenna for analysis purposes is shown in FIG. 3. The slot array antenna 10 is composed of a selected number of elements, which in the preferred embodiment is ten elements, shown as cross lines 22. Also shown is a reference line 24 corresponding to horizontal reference line 16 of FIG. 1. Angle φ defines the angle between the reference line and a desired point in space depicted as 26. The resulting antenna E field at point 26 is a combination of the E field from each of the array elements 22. The distance D i is the distance from the horizontal reference line 24 to the ith element. For a parallel slot antenna the resulting amplitude and phase of the antenna pattern from the aggregate of the slots is defined as E(φ), where E(φ) is a function which is proportional to each of the complex voltages A i at the ith slot and is a common function well known to those skilled in the art. The E field at point 26 for a parallel slot antenna as shown in FIG. 7 is determined by the equation: ##EQU1## Where λ s is the wave length of the desired center frequency and j is the imaginary operator. If the angle φ is stepped through k discrete steps then the resulting E field for each angle φ k is given by: ##EQU2## This last equation can be rewritten in matrix form as ##EQU3##
Since the expression ##EQU4## must be inverted to determine [A i ], it is necessary that the sample points indicated by the dotted lines 20 of FIG. 2 be equal to the number of slots or i elements shown in FIG. 3. Satisfying this condition it is possible to invert the e matrix to arrive at the amplitude in terms of magnitude and phase for each of the I slots as shown below: ##EQU5## The E field is the desired pattern, and the absolute magnitude is not important at this point, but rather the relative amplitude for each of the angles φ is all that is necessary.
All other elements are given except D i which initially must be assumed and will be determined with more precision in an iterative process in conjunction with other equations given below.
FIG. 4 is an electrical equivalent circuit of a portion of the slot array antenna showing an equivalent electrical representation of two of the slots and the wave guide portion between the slots. Specifically a slot has either an equivalent parallel conductance or an equivalent series resistance depending on the orientation of the slot in the waveguide and the coordinate system used to define the orientation of the slot as is well understood by those skilled in the art. The ith slot shown in FIG. 4 has either an equivalent shunt conductance 28 or an equivalent series resistance 30, and the i+1 slot has either an equivalent shunt conductance 32 or an equivalent series impedance 34. In the preferred embodiment of this invention only resonant slots are used which appear as pure resistive elements, but it will be understood by those skilled in the art that nonresonant slots could also be realized and their equivalent circuits inserted in these analysis for the equivalent resistances shown. Finally the length of line 36 between slots i and i+1 is depicted as L. In the derivation of A i given above (formula (3)), the result was a relative amplitude and relative phase for each of the i slots of the antenna as determined by A i . In order to synthesize the slot array antenna of the preferred embodiment, a first slot closest to the generating signal is chosen as a reference slot having a normalized amplitude of one and a phase of zero degrees. It is then necessary to determine how far down the waveguide the next slot is to be positioned in order to realize the proper phase relationship between the first and second slots. The amplitude of the signal emitted from the second slot will be considered later. For the voltages and currents depicted in FIG. 4 a matrix equation can be derived from equations associated with shorted and opened circuited terminations of transmission lines:
Short circuited transmission line (V 0 =0) ##EQU6##
Open circuited transmission line (I 0 =0) ##EQU7## Where Z is the distance from the termination, V I is the incident voltage, Z 0 is the characteristic impedance of the transmission line and β=2π/λ g . Combining equations (5) and (6) into matrix form and using the voltage and current conventions shown in FIG. 4: ##EQU8## Where V i and I i are the voltage and current respectively immediately after the ith slot; V i+1 and I i+1 are the voltage and current respectively immediately preceeding the next slot toward the termination from the i th slot; and θ equals 2π/λ g L.
This matrix (7) can be multiplied and expanded into a series of equations as shown below (all impedances normalized to Z 0 ):
V.sub.i+1 =cos θV.sub.i -j sin θI.sub.i (8)
REAL[V.sub.i+1 ]=cos θREAL[VI.sub.i ]+sin θIMAG[I.sub.i ](9)
IMAG[V.sub.i+1 ]=cos θIMAG[V.sub.i ]-sin θREAL[I.sub.0 ](10)
REAL[V.sub.i+1 ]REAL[I.sub.i ]+IMAG[V.sub.i+1 ]IMAG[I.sub.i ]=cos θ(REAL[V.sub.i ]REAL[I.sub.i ]+IMAG[V.sub.i ]IMAG[I.sub.i ]) (11) ##EQU9##
Finally the angle θ which is equal to the 2π/λ g time L of FIG. 4 is given by ##EQU10## However since |V i+1 | is not important, only the angle of V i+1 , then for the real [V i+1 ] one can substitute the cosine of the angle of V i+1 , and the imaginary part of V i+1 is equal to the sine of the angle of V i+1 . Equation (15) reduces to ##EQU11##
Once the proper spacing between the two adjacent slots, i and i+1, has been determined, then V i+1 and I i+1 can be determined using equation 7. The next slot spacing is determined using equation (16), wherein V i for the next slot spacing is equal to V i+1 of the previous slot spacing calculation minus any voltage drop in the equivalent series resistance of the slot; and I i for the next slot spacing is equal to I i+1 of the previous slot spacing calculation minus any current lost in the equivalent shunt conductance of the slot. The calculation of the magnitude of the series resistance or shunt conductance is shown below.
FIG. 5 is a complete electrical equivalence schematic of the parallel slot array antenna showing shunt conductances representative of each of the slots, and a mismatched terminating network 40 comprised of a shunt capacitor 42 and a terminating resistor 44. The values of capacitance 42 and resistance 44 and their relative positions are determined by standard Smith chart techniques or equivalent methods as for example equation (7) so that the impedance looking into the termination just to the right of the last conductance 46 is a complement of the impedance looking back towards the generator at the same point. The spacing between elements or slots is as described above. Energy from the sending or generating end propagates down the wave guide and a portion is radiated at each of the slots in turn until a percentage of the generated signal is absorbed by the terminating resistance 44. Note that these conductances or resistances set up standing waves inside the wave guide, and the derivations described in this application account for these standing waves to thereby accurately predict the amplitude and phase emitted from each of the slots. The power radiated and absorbed by the slot array antenna is given by ##EQU12## wherein K is a constant, P T is the total power into the antenna, and P L is the power absorbed by the load impedance 44. This equation can be rewritten in the form ##EQU13## The power at each element is equal to
P.sub.i =KA.sub.i.sup.2 (19)
since
P.sub.i =|V.sub.i |.sup.2 G.sub.i (20)
and
∠V.sub.i =∠A.sub.i (21)
therefore
K|A.sub.i |.sup.2 =|V.sub.i |.sup.2 G.sub.i (22)
and ##EQU14## which determines the amount of shunt conductance for each of the elements 38 of FIG. 5 or series impedance for the elements of FIG. 6.
FIG. 6 is an equivalent circuit of an angled slot array antenna wherein the angled slots are represented by series impedances 48 rather than the shunt conductances 38 of FIG. 5. Other than this difference, the discussion with regard to FIG. 5 is also applicable to FIG. 6.
The amount of the conductance for the parallel slot antenna is determined by the spacing from the center line of the wave guide as is well known by those skilled in the art. However, for the slanted slot antenna the amount of conductance is determined by the angle α of the slot with respect to the long axis of the wave guide. The slanted slots also introduce an additional term, cosine α, into the equations given above for A i such that equation (1) becomes ##EQU15## and the resulting A i matrix becomes ##EQU16##
The equations given above; i.e. the A i amplitude and phase, equations (4) and (25), the length of the line, equation (7), and the relative magnitude of each of the shunt conductances, or series impedances, equation (23); must be cycled through an iterative procedure such that the distances of spacing determined by the equation (7) is used for the D i term of the equations (4) and (25), and the magnitude of the shunt conductance or series impedance is used in the equations for solving for L to determine the spacing between the slots of the array. The iterative technique is continued until an acceptable deviation from the desired pattern is obtained by calculating the resulting E field using the last defined A i and D i terms after a number of iterations and comparing it to the desired E field.
FIG. 7 shows a physical layout for a ten slot parallel slot array antenna used to realize the antenna pattern shown in FIG. 1 and FIG. 2. The design center frequency of the preferred embodiment is 9.25 gHz and the wave guide stock is WR90. The physical dimensions for the slot array antenna is given in the following table:
______________________________________ Distance Distance From From CenterlineSlot Preceding Of Wave Length WidthNo. Slot Guide of Slot Of Slot______________________________________52 0 .023 in. .611 in. .031 in.54 .922 in. -.039 .612 .06256 .9291 .061 .613 .06258 .9002 -.088 .617 .06260 .8917 .131 .624 .06262 .6738 -.177 .633 .06264 .8316 .130 .624 .06266 .9381 -.094 .094 .06268 1.1400 .056 .613 .06270 1.1612 -.075 .615 .031______________________________________
The distance from slot 70 to variable capacitor 72 of the termination is 1.028 inches. The resistive termination 74, equal to the characteristic impedance, is placed at a convenient location. Note that the slot spacing is uneven and the deviation from each of those slots from the center line is also not even, but such spacing and such deviation from the center line is necessary to obtain the desired amplitude and phasing from each of the slots. These slots are also resonant slots although as mentioned before a similar antenna could also be fabricated using nonresonant slots. The realization of the slots from the electrical parameters given is described in prior art and well known to those skilled in the art. See, for example, Ivan Kaminow and Robert Stegen, "Wave Guide Slot Array Design", Hughes Aircraft Company, Technical Memorandum No. 348, July 1954, National Technical Information Service No. ADO 63600.
FIG. 8 is another realization of the antenna pattern of FIG. 1 and FIG. 2 wherein slanted slots are employed. This is also designed to operate at 9.25 gHz. Slanted slots 76, 78, 80, 82, 84, 86, 88, 90, 92, and 94 are spaced the same as parallel slots 52, 54, 56, 58, 60, 62, 64, 68, 70 of FIG. 7, and a termination capacitor 96 and a termination resistance 98 are spaced the same as, and are equal to, termination capacitor 72 and termination resistance 74 of FIG. 7.
The slots are slanted as given in the following table with the center of each slot falling on the center line of the waveguide.
______________________________________ Angle α FromSlot Center Line______________________________________76 3.550 Degrees78 -5.73380 9.183082 -13.73384 20.70086 -28.00088 20.26790 -14.66792 8.53394 -11.683______________________________________
A positive angle α corresponds to a counter-clockwise rotation of the slot with respect to the long axis of the waveguide. All of the slots are 0.621 inches long and 0.064 inches wide. Experimentation has shown that the slanted slots provide a more uniform antenna pattern with respect to the azimuth of the antenna of FIG. 1. This has been attributed to a decrease in mutual coupling between the slots of the antenna.
FIG. 9 illustrates a slot array antenna having angled slots in the narrow wall. The position and dimensions of these slots are determined using the same equivalent circuit for the parallel slot antenna of FIG. 7, and the aforementioned reference.
Thus a slot array antenna fabrication method has been shown which provides substantial control of phase and amplitude from each of the slots and which provides a matched impedance to a generating source. Also a slot array antenna has been realized which has a relatively short length and which utilizes both the incident and reflected waves to develop a proper antenna pattern. While the preferred embodiment is for a single antenna pattern, the techniques described above could be used for a large number of antenna patterns.
While the invention has been particularly shown and described with reference to the preferred embodiments shown, it will be understood by those skilled in the art that various changes can be made therein without departing from the teachings of the invention. Therefore, it is intended in the appended claims to cover all such variations as come within the scope and spirit of the invention. | A specified pattern slotted waveguide antenna is achieved by controlling the amplitude and phase of each slot of the array. The amplitude and phase of each slot is controlled by selecting the proper spacing between slots, the proper offset or slanting of each slot from the long axis of a waveguide, and the proper termination of the waveguide. The selection technique considers both the incident and reflected voltages in the waveguide to produce the desired amplitude and phasing at each of the slots, and also provides a proper load to a generating signal at center frequency. | 7 |
BACKGROUND TO THE INVENTION
The present invention relates in general to waste gas recovery systems.
It is well known to burn off or discharge waste gas arising in process plants used in the oil and chemical industries. Normally, the waste gas is passed to a flare which is elevated and is burnt off at the top of the flare. Nowadays, there is a tendency to utilize recovery systems which process waste gas for utilization as a fuel. The recovery system would supplement the normal flare system so that the latter would still operate in abnormal emergency conditions where there is a need to dispose of a large quantity of waste gas. A recovery system is described in the U.S. patent application of R. Lintonbon and D. Shore, Ser. No. 949,091 filed Oct. 6, 1978 which employs control means to ensure that the recovery system is able to cope with expected variations in pressure and flow rates of the gas.
A general object of the present invention is to provide an improved form of recovery system. More particularly, an object of this invention is to provide a recovery system which will ensure that the waste gas recovery is achieved in a safe, reliable manner without adversely affecting the normal flare system so that on no account could air be drawn into the flare system, thereby creating a dangerous situation.
SUMMARY OF THE INVENTION
As is known, the present invention relates to a waste gas recovery system which employs a compressor which takes in the raw waste gas and passes the compressed gas to an output and, preferably, through a cooler to the output. In accordance with this invention as set forth hereinafter, parameters are sensed in the system and control functions are initiated to protect the compressor to ensure that the compressor is not starved of gas and does not operate under adverse conditions, leading to excessive temperatures and also to ensure the compressor is isolated from the inlet, and hence from the flare system, should the gas pressure drop below a safe level.
In one aspect, the invention provides a method of controlling the operation of a waste gas recovery system which employs a compressor taking in raw waste gas from a main inlet and passing compressed waste gas to a main outlet; said method comprising sensing the temperature of the gas at the outlet of the compressor, operating control means in accordance with the sensed temperature to act on the gas fed into the compressor to reduce the temperature in the event of a sensed temperature rise, sensing the pressure of the gas fed to the compressor with a plurality of individual pressure-sensing means, utilizing one of said pressure-sensing means to control the drive speed of the compressor and to adjust an adjustable throttle valve to regulate the gas flow and utilizing the collective pressure-sensing means to operate shut-off means to isolate the compressor from the inlet means in the event of a sensed pressure falling below a minimum safety threshold level.
The temperature control can serve to cool and stabilize the outlet gas while the pressure control serves to regulate the gas flow supply to the compressor. Preferably, the operation of the shut-off means is accompanied by halting of the compressor in the event of pressure failure or drop and this can be accomplished by a known vacuum switch as part of the compressor controls.
A waste gas recovery system made in accordance with the invention may comprise a main inlet for receiving raw waste gas for processing, a compressor connected to the main inlet to receive and compress the waste gas, a main outlet for discharging the compressed waste gas, means for sensing the temperature of the gas at the outlet of the compressor, temperature control means responsive to the temperature sensing means and operable on the gas fed to the compressor to reduce the temperature of the gas at the outlet of the compressor in the event of a sensed temperature rise, a plurality of pressure-sensing means for individually sensing the pressure of the gas being fed to the compressor, means for driving the compressor at a selectively-variable speed under control of a first of said pressure-sensing means, an adjustable throttle valve for further regulating the flow of gas to the compressor under control of said first pressure sensing means and shut-off means for isolating the compressor from the main inlet when the pressure sensed by the collective pressure-sensing means falls below a minimum safety threshold.
The temperature control means may constitute a control valve or valve means operable to inject liquid acting as a coolant into the waste gas entering the inlet of the compressor, and/or a control valve or valve means operable to recycle gas from the outlet of the overall system back to the inlet of the compressor, in the event that the temperature should rise beyond a predetermined value.
The first pressure-sensing means which controls the compressor drive and the adjustable throttle valve closes the latter in the event that the pressure falls below the safety level. Hence, the throttle valve constitutes part of the shut-off means. Another pressure-sensing means may act to shut-off the control valve or valve means which allows re-circulation gas to pass to the compressor inlet so that this valve or valve means also constitutes part of the shut-off means. This other or second pressure-sensing means may act to disable or interrupt the control signal path between the temperature sensing-means and the associated valve or valve means allowing gas re-circulation to effect the closure of this valve or valve means. A further pressure-sensing means may also act to shut off a further valve constituting part of the shut-off means. This further valve may be between the main inlet and the compressor inlet and, more preferably, between the main inlet and the throttle valve.
It is preferable, also, to utilize one or more knock-out drums to remove liquid as condensate from the waste gas being processed. This liquid can be collected and used as the coolant injected into the inlet gas of the compressor. Thus, the main inlet can be connected to an inlet knock-out drum for removing liquid as condensate from the raw waste gas and the main outlet can be connected to an outlet knock-out drum for removing liquid as condensate from the compressed waste gas for discharge. Preferably, the liquid condensate is stored in a header tank maintained under a substantially constant pressure head. The header tank is preferably subjected to internal gas pressure and control means or pressure regulators can be used to take off excess gas from the header tank or to feed supplementary gas from part of the system, conveniently, at the outlet thereof, back to the header tank to maintain this internal gas pressure within a predetermined range.
Preferably, a control valve serves to prevent excessive gas pressure from building up in the outlet knock-out drum. This valve may open at a certain pressure to permit gas to be fed from the outlet knock-out drum back to the compressor inlet.
Instead of using condensate as the coolant, it is possible for a separate coolant to be supplied to the compressor inlet in case of need.
It is desirable to cool the compressed waste gas. A heat exchanger can be provided for this purpose. Coolant can be circulated through the heat exchanger and the compressor and preferably this coolant can be itself cooled by passage through another heat exchanger.
The invention may be understood more readily, and various other preferred features of the invention may become apparent, from consideration of the following description.
BRIEF DESCRIPTION OF DRAWING
An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, which is a block schematic representation of a waste gas processing and recovery system made in accordance with the invention.
DESCRIPTION OF PREFERRED EMBODIMENT
As shown in the accompanying drawing, the system consists of a number of component units and devices variously interconnected by pipes or conduits defining liquid and gaseous flow paths. The system employs two knock-out drums; namely, an inlet knock-out drum 10 and an outlet knock-out drum 11. The drums 10,11 are respectively associated with liquid-level sensing and control devices 12,13. The device 12 is connected via isolating valves 50,51 to the interior of the drum 10 to sense the level of condensate liquid therein and to provide a control signal dependent on the sensed level. A visual indication of the condensate liquid level in the drum 10 is provided by a level gauge 52 connected to the interior of the drum 10, via isolating valves 53,54. The level signal provided by the device 12 controls an electric motor 14, which drives a pump 16, which draws liquid condensate from the drum 10 from time to time via an isolating valve 58. The pump 16 feeds the liquid to a header tank 17 via an isolating valve 55, a three-way control valve 56 and a non-return valve 57.
The device 13 is similarly connected to the interior of the drum 11 via isolating valves 59,60 to sense the level of condensate liquid therein and provides a control signal dependent on the sensed level. A pressure regulator 64 is also connected to the device 13. A visual indication of the condensate liquid level in the drum 11 is provided by a level gauge 61 connected to the interior of the drum 11 via isolating valves 62,63. The level signal provided by the device 13 operates a control valve 30, which permits or inhibits the flow of liquid condensate from the drum 11 to the header tank 17.
A liquid level sensing and control device 70 is connected to the interior of the tank 17 via isolating valves 71,72 to sense the level of condensate liquid therein and provides a control signal dependent on the sensed level. A visual indication of the condensate liquid level in the tank 17 is provided by a level gauge 73 connected to the interior of the tank 17 via isolating valves 74,75. The level signal provided by the device 70 controls the control valve 56. In the event of liquid build-up in the tank 17 beyond a certain level, the valve 56 is operated by the signal from the device 70 to divert the liquid from the pump 16 to a drain DR via a restriction orifice 76, a non-return valve 77 and an isolating valve 78. The tank 17 is also provided with an overflow system which is effective in the event of further excessive liquid build up after the valve 56 has diverted the liquid from the pump 16. This overflow system comprises a liquid control device 79 connected to the interior of the tank 17 via isolating valves 80,81 serving to feed liquid back to the top of the drum 10, as shown.
When the system initially commences operation, or after shut down, it may be necessary to supply priming liquid to the tank 17. For this purpose, a priming line PR leads to the tank 17 via an isolating valve 82.
It is desirable to provide a certain reasonably constant gas head pressure in the tank 17 and in the system, as illustrated, flash gas is taken off from the tank 17 or blanket gas fed to the tank 17 to maintain the desired pressure via a common gas line CL and control means described hereinafter.
Waste gas is fed into the drum 10 via a main gas inlet IN and an isolating valve 83. The gas outlet from the drum 10 is fed via an isolating control valve 84 to an adjustable-throttle pressure control valve 27 and thence via a strainer unit 25 and a silencer 26 to the inlet of a compressor 20. The outlet from the compressor 20 is fed through a silencer 23 and a heat exchanger 24 to the knock-out drum 11. The outlet from the drum 11 is fed via a non-return valve 33 and an isolating valve 85 to a main gas outlet OUT. The compressor 20 is driven by an electric motor 15, a speed control arrangement 21 and gearing in a gear box 22. The arrangement 21 may operate to effect electrical or mechanical speed control of the compressor drive.
A pressure sensing and control device 19 senses the pressure prevailing at the outlet of the drum 10 and provides a corresponding control signal. More particularly, the device 19 is connected through an isolating valve 87 to the junction between the valves 84 and 27 and to a one-way vent 88. A pressure regulator 89 is also connected to the device 19. The signal produced by the device 19 serves to control the speed control arrangement 21 and the valve 27. Thus, according to the pressure sensed by the device 19, the drive speed of the compressor 20 is varied and the valve 27 is adjusted progressively to vary its throttle opening.
A temperature sensing and control device 18 senses the temperature prevailing at the outlet of the compressor 20 and provides a corresponding control signal. A pressure regulator 86 is connected to the device 18. A control valve 28 is connected via an isolating valve 90 to the tank 17 and to the compressor inlet. The signal provided by the device 18 controls the valve 28 which opens to draw off liquid from the tank 17 for injection into the compressor inlet when the device 18 detects a temperature level in excess of a predetermined value.
A re-circulatory gas path is established between the outlet of the drum 11 and the inlet of the strainer unit 25 via a control valve 29. The signal produced by the device 18 also controls the valve 29 so that a certain proportion of the outlet gas can be fed back from the drum 11 to the compressor 20, when the valve 29 is opened. The valve 29 would normally be set to actuate at a higher temperature than the valve 28. The signal path from the device 18 to the valve 29 can be interrupted by a switching device 91 which may be a pneumatic relay. The switching state of the device 91 is controlled by means of a pressure sensing device 92. This device 92 is connected via an isolating valve 93 to sense the pressure at the inlet of the strainer unit 25. The device 92 is also connected to a one-way vent 94 and to a pressure regulator 95.
The gas head in the drum 11 is connected via a regulating device 96 to the outlet from the drum 10 so excessive pressure build up in the drum 11 can be precluded.
The valve 84 is connected to a further pressure sensing device 97 which, in turn, senses the pressure at the input to the valve 84. The device 97 is connected to a pressure regulator 98. The compressor 20 would be additionally protected with the aid of a vacuum switch as known per se.
The gas line CL to the tank 17 is connected via a pressure regulating device 99 to the junction between the valves 84,27 and via a pressure regulating device 100 to the junction between the valve 33,85. Excess pressure, as caused by flash gas in the tank 17, will cause the device 99 to open to relieve the pressure in the line CL. Conversely, a fall in the head pressure in the tank 17 will cause the device 100 to open to draw in blanket gas from the outlet of the drum 11. The devices 99,100 which are, of course, set to actuate at different pressures thus supply and draw off gas from the tank 17 to maintain the liquid therein under a reasonably constant pressure.
The system employs circulating coolant to cool the compressor 20, the gear box 22, the speed changing arrangement 21 (where this is a mechanical arrangement) and the heat exchanger 24. This main circulating coolant is itself cooled separately by a further heat exchanger 101. In this embodiment, the main circulating coolant is fresh water while the coolant for the heat exchanger 101 can be brackish water unsuitable to pass through the system. The main coolant water is supplied to a header tank 102 employing a ball valve or the like to maintain a constant level of water in the tank 102. The tank 102 would normally employ an overflow pipe. The tank 102 feeds the coolant water to the inlet of a pump 103 drive by a motor 104. In the event of a failure in the supply of water to the tank 102, the motor 104 and the pump 103 are designed to shut down. This can be achieved by using a water level sensing device (not shown) which interrupts the power supply to the motor 104 should the water level drop to a minimum value. The pump 103 feeds the coolant water through an isolating valve 105 from whence the water splits into two paths, W1,W2. One path, W1, passes through an isolating valve 106 through the heat exchangers 23,101, as shown, and back to the pump inlet via an isolating valve 107. The other path W2, is in turn sub-divided into two paths, W3,W4. One path, W3, passes through an isolating valve 108, and through cooling jackets of the gear box 22 and the compressor 20 to join the path W1 entering the heat exchanger 101. The other path, W4, passes through an isolating valve 109 and through the cooling jacket of the speed-changer arrangement 21 and joins the paths W1,W3 entering the heat exchanger 101.
The operation of the system is as follows:
The waste gas to be processed and arising in a plant enters the drum 10 at "IN" and a proportion of liquid entrained in the gas condenses in the drum 10. The gas then passes through the normally-open valves 84,27 through the strainer unit 25 and the silencer 26 into the inlet of the compressor 20. The gas is thence compressed and passes through the silencer 23 and through the heat exchanger 24, which cools the gas, to the drum 11. Liquid entrained in the gas again condenses in the drum 11 and the gas taken from the outlet of the drum 11 to the outlet "OUT" is suitable to be conveyed into a fuel gas main of the plant.
Variation in the pressure of the incoming gas fed to the compressor 20 is detected by the device 19 and variation in the temperature of the gas at the outlet of the compressor 20 is detected by the device 18. The device 19 directly controls the speed of the compressor drive and the speed of the compressor 20 is automatically varied to compensate for any change in the incoming gas pressure. In addition, the device 19 controls the throttle opening of the valve 27 in accordance with the sensed pressure. This pressure-sensitive control ensures that the compressor 20 operates within a certain speed range and maintains reasonably constant operating characteristics while the inlet gas to the compressor 20 is kept within a desired range of pressure variation. When the compressor 20 is operating at minimum speed, a further reduction in the pressure of the incoming gas would give rise to a temperature rise at the outlet from the compressor 20. At a certain temperature, the device 18 actuates the valve 28, which then injects liquid taken from the header tank 17 onto the gas passing into the compressor 20. The liquid tends to cool the gas and the device 18 may cause the valve 28 to cycle and switch on and off to restrict the temperature of the gas at the outlet of the compressor 20. In the event that the injection of fluid is not sufficiently effective to restrict the temperature rise, the valve 29, which is set to switch at a higher temperature than the valve 28, will be opened by the device 18. Gas is now re-circulated from the drum 11 back to the compressor 20 and this gas, which is cooled by the heat exchanger 24, will assist in reducing the temperature of the gas in the compressor 20. In this event, the compressor 20 operates with gas re-circulating between the outlet and inlet and this gas, which is cooled by the heat exchanger 24, and may be additionally cooled by liquid injection, ensures that the compressor 20 is protected.
Nevertheless, if the pressure of the waste gas drops still further to a minimal safety threshold value, or should fail entirely, it is imperative to isolate the compressor 20 from the inlet IN to avoid the creation of a suction at the inlet IN. If the pressure falls below the safety threshold, the switching device 91 will be actuated by the pressure sensing device 92 to interrupt the control path from the device 18 and this will cause the valve 29 to close. The valve 27 is also closed directly by the device 19 and the valve 84 would also be closed with the aid of the device 97. Thus, under such adverse or failure conditions, the valves 27,84,29 form a shut-off means to ensure the compressor 20 is isolated from the inlet IN. The compressor 20 may still have liquid injected at its inlet by the valve 28 but its vacuum switch would sense that no gas is being received and would normally shut down the compressor 20 entirely under these adverse conditions.
Although in the illustrated embodiment the compressor 20 is driven by an electric motor, it is possible to utilize a turbine as the drive means.
The units and devices of the system, as illustrated and described, can be conveniently mounted on one or more skid structures designated by chain-dotted lines SK101, SK102, which facilitates installation on site.
Certain of the units and devices would need to be adapted to the particular conditions and requirements prevailing. Nevertheless, in a typical system:
the compressor 20 can be an Aerzen type VRO 325L/125L;
the valves 28,29 can each be a Fisher type 657A or 657R;
the devices 18,19,92,97 can each be a Taylor Series 440;
the valve 27 can be a GEC Elliot type 7600;
the pumps 103,16 can be Ryax S1H1 type pumps;
the electric motors 104,15 can be made by Brooks and are compatible with the pumps 103,16;
the electric motor 15 can be made by Brush and is compatible with the compressor 20 and the drive arrangements 21,22.
the regulators 99,100 can be Fisher type 630;
the regulators 64,98,89,86,95 can be Fisher type 67FR;
the non-return valves 33,77,57 can be Hattersley-Newman Hender type 4936.
the devices 12,70 can be Mobrey type LS1Z/1;
the device 13 can be a Fisher type 249B-2500;
the vent valves 94,88 can be Hattersley-Newman Hender type 528;
the three-way valve 56 can be Fisher type 657-YY;
the control valves 84,30 can be Fisher type 657-AR;
the level gauges 52,61,73 can be Klinger type 21;
the isolating valves 50,51,53,54,55,58 62,63,71,72,74,75,80,81,105,83,85,90,107 can be Hattersley-Newman Hender type 7767;
the isolating valves 59,60,78,82,108,109, 106, can be Hattersley-Newman Hender type "V" reg;
the isolating valves 87,93 can be Hattersley-Newman Hender type 528;
the relief valve 96 can be Farris type 2600; and the relay 91 can be a Fisher type 2601A. | A waste gas recovery system employs a compressor which takes in raw waste gas from an inlet knock-out drum and passes compressed gas through a heat exchanger to an outlet knock-out drum. The temperature at the outlet of the compressor is sensed by a device which operates valves to inject liquid coolant into the compressor inlet and to re-circulate gas back from the outlet of the outlet knock-out drum to inhibit an excessive temperature rise. A pressure-sensing device senses the pressure of the gas passing into the compressor and controls both the speed of the compressor and an adjustable throttle valve to regulate the gas flow. The throttle valve is closed automatically should there be a fall in the pressure of the gas at the inlet below a safe level. In this event, further pressure-sensing devices act additionally to close the recirculating gas valve and a further valve in the main inlet flow path to reliably isolate the compressor. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates generally to functional verification of properties associated with circuit designs and, more particularly, to an integrated proof flow for the verification of such properties.
DESCRIPTION OF THE RELATED ART
Verification is typically the most time-consuming component in a circuit design process. Failing to detect functional design errors early in the design stages usually leads to expensive re-spin of the designs. This re-spin includes diagnosis and correction of the errors, logic and physical re-synthesis, and even re-manufacturing of the chips that can be very time-consuming, costly and delay the time-to-market of a product. If the chip designs are already used in some released products, this can even lead to product recalls that are very devastating to a company.
Property checking is an approach for verifying the functionality of a circuit design. It involves proving one or more properties specified for a circuit design. A property, which can also be called an assertion, may be logical (e.g., Boolean) and/or temporal, and describes behavior of one or more signals in the circuit design.
Formal verification of a property verifies that the property holds for all combinations of input signals and sequences over time. For example, to verify that a property holds, formal verification tools or methods attempt to check all states possible during operation of the circuit design, where the operation starts from one or more initial states of the circuit design. Successfully checking all the states ensures that the property is not violated. During the state space search, if a contradiction is found, the property is disproved and a counter example can usually be generated to demonstrate how the violation occurs.
Formal verification is therefore very useful for uncovering corner-case bugs because it determines whether or not a property is true in the circuit design by exercising all possible behavior of the circuit design. However, due to the exceedingly large and complex circuits that are being designed today, formal verification is subject to the classical state explosion problem. For example, a typical circuit design may contain hundreds of thousands of state variables (state-holding elements, i.e. flip flops), where each state variable may have one of two values, either 0 or 1. The number of possible value combinations (or states) that are required to be checked by formal verification techniques is extremely large, and some states can only be reached after a very large number of cycles. It is therefore very difficult to perform state space search exhaustively for large designs. Such complexity presents memory and time constraints that make formal verification for large, but typical, circuit designs intractable.
Nonformal verification, (also called semi-formal verification), is another approach to handle difficult and complex circuits and properties. Nonformal verification checks the property over a subset of the states that are of concern in formal verification. One or more types of nonformal verification may be performed. Although nonformal verification does not search all the possible states of a circuit, it can usually handle large circuits and may find bugs that cannot be found by formal verification techniques. One or more nonformal verification techniques may be performed on a circuit for a given set of properties, and one nonformal verification technique may find bugs which are missed by another nonformal verification technique.
One example of nonformal verification is bounded verification, which determines whether or not a property is true in the circuit design for a specific number of cycles. In contrast to the exhaustive search associated with formal verification (also known as unbounded verification), bounded verification is called nonformal because it only checks the behavior exhaustively for a limited number of cycles. Its main benefit is that the limitation on the number of cycles usually greatly reduces the complexity of the verification problem.
Another example of nonformal verification technique is the local search based multi-point proof method. In this method, bounded search up to a limited number of cycles is performed by starting from different states. These different starting states can be determined by the program automatically and/or can be specified by the user. By starting from different states and performing limited cycle searches from those states, the chance of finding bugs in the design is increased, in contrast with using just a single starting state.
Simulation is another nonformal verification approach used to verify a circuit design. Simulation techniques typically utilize simulation vectors to determine whether or not a circuit design functions in an expected manner. Such simulation runs are usually non-exhaustive, and various coverage metrics, for example, hardware description language (HDL)-based code coverages, are used to assess the quality of the simulation vectors and determine when to stop the simulation process. Conventional simulation techniques do not maintain prior test or coverage information, and the verification vectors are derived independent of prior test or coverage information. For example, simulation vectors are typically manually derived by designers or randomly generated from the high-level description of the design and its environment. Therefore, the number of simulation vectors necessary to suitably verify a circuit design can be prohibitive. Techniques have been proposed to derive more effective simulation vectors, so that specific target states can be reached more easily and also consider the states that have been reached by prior simulation to avoid redundant work. Such techniques hold the promise to provide a more effective simulation environment.
Formal verification, and nonformal verification (e.g., bounded verification, multi-point proof, and vector-based simulation) are verification techniques that have their own advantages and disadvantages. There is a need to tightly integrate all these techniques in a unified verification framework to provide a robust verification solution. It is also necessary to further improve the vector based simulation process so that more effective simulation vectors can be generated to improve the overall functional coverage.
SUMMARY
Accordingly, some embodiments of the present invention provide integrated proof flow methods and apparatuses. Integrated proof flow refers to attempting both formal verification and nonformal verification. A coverage metric can be changed by both attempting formal verification and by attempting nonformal verification.
Some embodiments of the present invention provide proof flow methods that integrate formal verification and nonformal verification (e.g., bounded verification, multi-point proof, and/or vector-based simulation) to prove one or more properties in a circuit design.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an example of an overall proof flow.
FIG. 2 shows an example of modifying a coverage metric of a property.
FIG. 3 shows an example of attempting nonformal verification.
FIG. 4 shows an example of a computer capable of executing proof flow.
DETAILED DESCRIPTION
Referring to FIG. 1 , one embodiment of a proof flow method for a set of properties associated with a circuit design is illustrated. Examples of properties are “signal A should always be True” and “signals A, B, and C should always satisfy the relationship that A×B=C for all clock “cycles”.
For a given property, one or more coverage metrics can be defined. If multiple coverage metrics are defined for a given property, the multiple coverage metrics can be of the same or different kinds. In the case where at least two coverage metrics of the same kind exist, different criteria can be used (e.g., if at least two metrics are of the toggle-based metric type, the sequential elements can have different weights when calculating the overall coverage).
One such metric is the state-based metric, where the goal is to search all the reachable states of the circuit and check the correctness of the property in each of the states. If the property can be verified by formal verification, it means all the reachable states are searched and therefore the coverage is 100%. However, if only a partial set of reachable states can be searched due to, for example, memory and/or runtime constraint, then the coverage metric can be some measure of the number of states searched, for example, the number of states searched divided by the total number of reachable states.
Another metric is the toggle-based metric. For every signal driven by a sequential element in the cone of logic of the property, the goal is to toggle the signal during the checking of the property. In some embodiments, the more such signals are toggled, the more thoroughly the property is checked. In some embodiments, some such signals may not toggle, and such situations should be taken into account. If a property can be verified by formal verification, the toggle based coverage is 100%. Otherwise, if there are N sequential elements in the logic cone of the property, and M out of the N elements can not be toggled (e.g., their value is either constant 0 or 1), then the coverage metric can be a measure of toggled elements (e.g., sequential elements), for example, the number of sequential elements that are toggled during the property verification divided by (N−M).
Another kind of coverage metric is the code structure based metric. Code structure based coverage metrics can measure the effectiveness of simulation. Examples of code structure based metrics are line coverage metrics (i.e., how many lines of the RTL code have been exercised in simulation), branch coverage metrics (i.e., in all the possible execution branching conditions, how many of them are exercised in simulation), and path coverage metrics (i.e., in all the possible execution paths of the code, how many of them are exercised in simulation). For the verification of a particular property, the correspondence between the logic cone of the property and the RTL code can be established. Then, one or more code structure based coverage metrics can be used to measure how well a property is verified. For example, for a line coverage metric, during the search process of verifying a property, the number of lines of the RTL code (corresponding to the property logic cone) which have been exercised can be kept track of. This information can be used to calculate the line coverage metric.
Another kind of coverage metric is the user-defined metric and there can be many variations. One example of user-defined metric is a set of key signals in the logic cone of the property that are selected by the user, and the goal of the verification is to exhaustively check all possible combinations of the set of key signals during property verification. Some combinations of the key signals may not be reachable, and such situation should be taken into account. If a property can be verified by formal verification, the key signal combination coverage is 100%. Otherwise, the coverage metric can be a measure of key signal combinations, for example, the number of key signal combinations divided by the total number of possible combinations of the set of key signals.
Yet another coverage metric can combine multiple kinds of coverage metrics.
For the given set of properties of a circuit design, the following steps can be performed for each of the properties, at least partly concurrently, at least partly before, and/or at least partly after, one another:
(i) a coverage metric is defined for one or more properties. A coverage metric that defines how well a property is proved can be defined by the tool automatically and/or by the user. If a property is proven by formal verification successfully, its coverage is 100%. The coverage of a property is less than 100% if it cannot be proven successfully by formal or nonformal verification due to, for example, a space or time limit. Using multiple techniques can increase the coverage of a property, to help satisfy the goal of verification by obtaining a high coverage for a property. By defining a coverage metric for a property, different techniques can be guided by the same coverage metric, and try to modify it, such as by increasing it.
(ii) a formal verification is attempted for one or more properties, and
(iii) a nonformal verification is attempted of one or more properties.
Formal verification can include one or more formal verification steps. Unbounded formal verification of a property is attempted, and the attempt may succeed or fail. Coverage information based on the coverage metric is calculated during or after the verification step.
Nonformal verification can include one or more nonformal verification steps. The nonformal verification steps can be selected from, for example, (a) attempting a bounded verification of a property with increasing numbers of cycles starting from an initial state, (b) attempting a bounded verification of a property with a limited number of cycles (which can be the same or different from each starting point, and can be determined by heuristics and/or manually by the user, etc.) beginning with different starting states, and (c) attempting a coverage-driven simulation of the property. Coverage information, based on the coverage metric selected in (i), can be calculated and updated in any of the nonformal verification steps (a), (b), and (c).
Each property can have identical or different optional nonformal verification steps of (a), (b), and (c). The bounds of the bounded verification of step (a) of the optional nonformal verification can be selected by the user or automatically by a program. The limited number of cycles and the different starting states of step (b) of the optional nonformal verification (from step (b)) can be selected by the user or automatically by a program.
FIG. 1 shows an example of a proof flow. In 110 , a property of a circuit design is accessed. For example, the property can be retrieved from a local location and/or remote location, and/or the property can be generated and accessed. In 120 , a coverage metric of the property is modified. In 130 , if more properties of interest exist, the proof flow can be repeated with another property.
Many other proof flow embodiments exist. Parts can be added, removed, rearranged, and/or changed. For example, multiple properties can be accessed, and/or multiple coverage metrics of one or more properties can be modified at least partly concurrently. Accessing the property and modifying the coverage metric can occur at least partly concurrently.
FIG. 2 shows an example of modifying a coverage metric of a property. In 210 , formal verification is attempted. In 220 , the coverage metric of the property is modified based on the attempted formal verification. In 230 , nonformal verification is attempted. In 240 , the coverage metric of the property is modified based on the attempted nonformal verification. In 250 , if more verification is to be attempted, the above can occur again and the coverage metric can be further modified.
Many other embodiments exist for modifying the coverage metric. Parts can be added, removed, rearranged, and/or changed. For example, the coverage metric can be modified at least partly concurrently with attempted verification. Attempted formal verification can occur after and/or at least partly concurrently with attempted nonformal verification.
FIG. 3 shows an example of attempting nonformal verification. In 310 , a nonformal verification technique is chosen. Depending on the result of 310 , a particular nonformal verification technique is attempted, such as bounded verification 320 , multi-point proof 330 , and vector-based simulation 340 . In 350 , the coverage metric is modified based on the attempted nonformal verification. In 360 , if more nonformal verification is to be attempted, then the above can occur again.
Many other embodiments exist for attempting nonformal verification. Parts can be added, removed, rearranged, and/or changed. For example, multiple nonformal verification techniques can be attempted, at least partly concurrently and/or at least partly sequentially. The coverage metric can be modified at least partly concurrently with attempted verification.
In some embodiments, the different nonformal verification techniques can be coverage driven.
In one example of a proof flow, given a 16-bit counter initialized to 0, an accessed property states that the counter never counts beyond 10,000. In this example, resources are exhausted beyond 4,000 cycles and the attempted formal verification failed. The coverage metric is state-based and 30,000 states have been searched during the formal verification proof. Nonformal verification is attempted. Bounded verification is attempted from each time frame number in a list of time frame numbers, e.g. {0, 2,000, 4,000, 5,000}, and results in an increase of the coverage metric from 30,000 states to 55,000 states out of the possible 65,536 states of the counter. Vector-based simulation is attempted to increase the coverage metric. Vectors are generated to simulate the accessed property that the counter never counts beyond 10,000. Unfortunately, due to resource limitations, such as time, only 6,000 additional states are reached in the vector-based simulation. The final coverage metric result is 61,000 states out of 65,536 states, or approximately 93%.
In another example of a proof flow, an accessed property about 2 signals, A and B, of a control circuit is that whenever A is true, B becomes true after 3 clock cycles. There are 330 flip-flops in the logic cone representing this property and a toggle-based coverage metric is used. Starting from an initial state, formal verification is attempted but fails after searching for 50 cycles. 150 flip-flops are determined to have both 0 and 1 configurations examined during the search and it is also found that 30 flip-flops cannot be toggled due to certain constraints of the circuit. The resulting coverage is therefore 150/(330−30)=50%. Multi-point proof nonformal verification is then attempted to increase the coverage. A set of starting states, which have been confirmed to be reachable since they are extracted from an existing simulation result of the circuit, are provided, and then limited-cycle searches are performed by starting from each of the set of starting states. 75 additional flip-flops are determined to have both 0 and 1 configurations examined during the multi-point nonformal proof. Therefore the coverage is increased to 225/(330−30)=75%. Finally coverage-driven vector-based simulation nonformal verification is attempted to target those flip-flops which have not been toggled. After generating and simulating 2500 vectors, an additional 50 flip-flops are toggled. The final coverage is increased to 275(330−30)=91%. The property is still not proven to be true because not all possible reachable states are searched. But there is a high confidence because 91% of the flip-flops have both 0 and 1 configurations examined during the application of formal and nonformal verification techniques.
FIG. 4 shows an example of a computer 400 that can execute a proof flow, which can be code 420 . The computer 400 can be connected to a network 410 . The computer 400 can execute code 420 with instructions to execute the proof flow. The computer 400 can have the code 420 preinstalled. The computer 400 can receive the code 420 over the network 410 , which can be connected to the computer via a link 430 , which can be a wireless and/or wired link. The code 400 can be in a temporary state (e.g., electrical, magnetic, and/or optical signal) and/or at least partly hardware, such as in a relatively permanent state (e.g., optical disk, magnetic disk, hard disk, temporary memory such as RAM, flash memory, processor). The computer 400 can have the code 420 installed via such a temporary and/or relatively permanent state hardware. Multiprocessor, multicomputer, and/or multithread implementations can be practiced. | Integrated proof flow methods and apparatuses are discussed. Integrated proof flow refers to attempting both formal verification and nonformal verification. A coverage metric can be changed by both attempting formal verification and by attempting nonformal verification. Some embodiments of the present invention provide proof flow methods that integrate verification and nonformal verification (e.g., bounded verification, multi-point proof, and/or vector-based simulation) to prove one or more properties in a circuit design. | 6 |
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and method for measuring the biopotential signals produced in a subject, and more specifically to an apparatus and method that is configurable to provide either a 1-channel operating mode or a mode resembling 2-channel operation.
BACKGROUND OF THE INVENTION
[0002] Electroencephalography (EEG) is a well established method for assessing the brain function by picking up the weak biosignals generated in the brain with electrodes on the skull surface. To obtain the biosignals, multiple electrodes are placed on the scalp of a patient in accordance with a recognized protocol. EEG has been in wide use for decades in basic research of the neural system of brain as well as clinically in diagnosis of various neurophysiological disorders.
[0003] The EEG signals received by the electrodes from the scalp are amplified by amplifiers which may be of the differential type to minimize electrical interference. Each amplifier has three inputs: 1) a positive signal input; 2) a negative signal input; and 3) a ground input. Consequently, even the most rudimentary 1-channel EEG measurement procedure requires the use of three electrodes. Applying electrodes to the scalp takes time and skill, requires skin preparation, e.g., removal of hair, and is especially difficult in a thick hair environment.
[0004] One of the special applications for EEG which has received much attention to during the 1990's is use of a processed EEG signal for objective quantification of the amount of brain activity for the purpose of determining the level of consciousness of a patient. In its simplest form, this usage of EEG allows for the automatic detection of the alertness of an individual, i.e. if he or she is awake or asleep. This has become a significant issue, both scientifically and commercially, in the context of measuring the depth of unconsciousness induced by anesthesia during surgery. Modern anesthesia practices use a sophisticated balancing technique with a combination of drugs for maintaining adequate hypnosis, analgesia, muscle relaxation, and/or suppression of the autonomic nervous system and blockage of the neuromuscular junction. The need for a reliable system for the monitoring of the adequacy of the anesthesia is based on both safety and economical concerns. An anesthesia dose which is too light can, in the worst case, can cause the patient to wake up in the middle of the operation and create a highly traumatic experience both for the patient and for the personnel administering the anesthesia. At the opposite extreme, the administration of too much anesthesia generates increased costs due to the excessive use of anesthesia drugs and the time needed to administer the drugs. Over dosage of anesthesia drugs also affects the quality and length of the postoperative period immediately after the operation and the time required for any long term post-operative care.
[0005] A significant main advancement in making the EEG-based measurement of the depth of unconsciousness induced by anesthesia an easy-to-use, routine procedure was a finding based on Positron Emission Tomography (PET) that determined that the effects of the anesthetic drugs on the brain are global in nature. This means that for many applications it is enough to measure the forebrain or frontal cortex EEG from the forehead of the subject. The forehead is both an easy to access and is a hairless location on the subject. Electrodes placed with an appropriate spacing between electrodes on the forehead can pick up an adequate signal originating from the anterior cortex in the brain. This discovery, together with development of a special algorithm, namely, the Bispectral Index (BIS), an electrode design requiring no skin preparation, as disclosed in U.S. Pat. No. 5,305,746, incorporated herein by reference, and a convenient integrated electrode array, as disclosed in U.S. Pat. No. 6,032,064, also incorporated herein by reference, have contributed to a viable commercial product manufactured and sold by Aspect Medical of Natick, Mass. capable of obtaining a measurement of the state or activity of the brain during delivery of anesthesia using an EEG system.
[0006] The '064 patent teaches a disposable EEG electrode array. One array has three electrodes for 1-channel measurement. A different array has four electrodes for 2-channel measurements. The 2-channel set-up is symmetrical in configuration and separately collects the signals between the mid-forehead and left and right mastoidal points, respectively. The 2-channel measurement configuration is used to determine the differences in the EEG signal in situations in which the right and left frontal hemispheres might be expected to produce different EEG signals. This can be caused, for example, by ischemia or burst suppression, i.e., EEG signals in discontinuous bursts, in either of the sides of the head, as well as artifacts in the EEG signals due to movement of the eyes of the subject or poor contact in one of the electrodes.
[0007] However, if it is desired to switch from 1-channel to 2-channel EEG measurements, with these prior art sensors it is necessary to remove the three electrode, 1-channel sensor and replace it with a four electrode, 2-channel sensor, and vice versa. This requires significant time and effort on the part of the technician taking the measurements as the first sensor must be removed before the second sensor can be positioned on the individual, and because the positioning of the second sensor must be precise in order to obtain an accurate measurement of the neurological activity of the subject.
[0008] It would, therefore, be desirable to develop a neurological activity sensor system which is capable of operation in both a 1-channel and 2-channel manner to obtain EEG measurements of the neurological activity of the subject. The sensor system should have as simple a construction as possible to minimize the amount of time and effort necessary to properly position the electrodes of the sensor on the subject prior to obtaining the measurements.
[0009] While the foregoing has discussed the use of EEG signals, it may also be desirable to obtain electromyographic (EMG) signals arising from the forehead of the subject. Should an anesthetized patient approach a state of consciousness, the frontalismuscle in the forehead of the subject may contract from a pain sensation or for other reasons. When sensed by appropriately placed electrodes, this muscle activity can provide an early indication that the subject is emerging from anesthesia.
SUMMARY OF THE INVENTION
[0010] It is, therefore, an object of the present invention to provide a low cost sensor system of simple construction having an electrode array with three basic EEG electrodes capable of performing measurements of neurological activity in different portions of the brain, such as the overall frontal cortex of the brain or the left or right hemispheres of the forebrain.
[0011] A further object of the invention is to provide a sensor system capable of obtaining EMG signals from the head of a subject.
[0012] It is another object of the invention to provide a sensor system and method of operating same which can be configured to selectively operate in a conventional 1-channel mode or in a manner to approximate a 2-channel measurement.
[0013] It is still a further object of the invention to provide a sensor system wherein the electrode array is manufactured to be disposable.
[0014] The invention employs an electrode array of three electrodes. The sensor system uses a switching arrangement connected to the electrode array to route signals from each of three electrodes forming the array in a manner that allows measurement of the biopotential difference between any pair of the three electrodes of the system while using the remaining electrode in each case as a ground electrode. To this end, a signal from each of the three electrodes can be selected by the switching arrangement for use as a positive input signal, a negative input signal or a ground signal to a signal processing unit, such as a differential amplifier to obtain a biopotential difference used to measure the neurological or muscular activity of the subject.
[0015] The switching arrangement can route the signals from the electrodes to form a 1-channel measurement mode to monitor the neurological activity of either the left or right hemisphere of the forebrain or overall frontal cortex of the brain. The switching arrangement can also route signals from selected pairs of electrodes to the differential amplifier in a pre-determined, alternating fashion to provide an essentially 2-channel measurement of neurological activity. EMG signal data is obtained in an analogous manner.
[0016] The sensor system and method of the present invention have significant advantages compared to a fixed 1-channel set-up. First of all, the system allows for the optimization of the signal quality regarding the signal-to-noise ratio in the signals of the electrode array. The system can automatically choose to start a measurement using the electrode on the frontal hemisphere that is receiving the strongest signal and/or the least amount of noise by sampling the signals and noise levels generated by each frontal hemisphere and received by each electrode prior to starting any measurement. Secondly, by switching 1-channel measurements using selected pairs of electrode signals back and forth in a predetermined sequence, this system can also work as a surrogate for a true 2-channel measurement system. The system can also be configured to monitor the status of the electrodes, and detect the origin of any interference or signal artifacts and for the diagnosis of any physiological changes that generate lateral asymmetry in the frontal cortex neural activity, such as changes in blood flow in one of the carotid arteries.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The following drawings illustrate the best mode currently contemplated of practicing the present invention.
[0018] In the drawings:
[0019] [0019]FIG. 1 is a perspective view of the sensor system for measuring biopotentials constructed according to the present invention and connected to a subject;
[0020] [0020]FIG. 2 is a plan view of the electrode array of the system of FIG. 1; and
[0021] [0021]FIG. 3 is a schematic view of the circuitry used in the system of FIG. 1 to direct input signals from the electrodes to signal processing unit inputs for measurement of signal differences between different selected pairs.
DETAILED DESCRIPTION OF THE INVENTION
[0022] With reference now to the drawings in which like reference numerals designate like parts throughout the disclosure, the sensor measurement system of the present invention is indicated generally at 10 in FIG. 1. The system 10 includes an electrode array 12 connected to a monitor 14 by a cable 16 . The array 12 transmits neurological activity signals received from the forehead 18 of the patient to the monitor 14 which carries out signal processing and numerically or graphically displays EEG or EMG data. The data may also be stored for future use.
[0023] As best shown in FIGS. 1 and 2, the electrode array 12 includes a central body 20 and a pair of side bodies 22 and 24 connected to the central body 20 by a pair of flexible arms 26 . The central body 20 , side bodies 22 and 24 and arms 26 are each formed of a flexible, resilient material which enables the arms 26 to flex with respect to the central body 20 . This allows the array 12 to conform to the shape of the subject's head 18 and to have the side bodies 22 and 24 positioned at the optional sites on the head 18 to detect activity producing biopotentials. The positioning of the array is shown generally in FIG. 1. The preferred material used in the construction of the electrode array 12 is a thermoplastic material, which also allows the electrode array 12 to be formed as a single unit, if desired, as shown in FIG. 1.
[0024] Each of the central body 20 and side bodies 22 and 24 includes an electrode 28 , 30 and 32 , respectively, disposed on one side of the electrode array 12 . Each electrode 28 , 30 and 32 is connected to a conductor 29 , 31 and 33 , respectively, that transmits biopotential signals received by the electrodes 28 , 30 and 32 from the forehead 18 . The electrodes and conductors are formed of a conductive material suitable for receiving and transmitting biopotentials, such as metallic foils or wires, vapor deposited or printed metallic layers, or the like. The electrodes 28 , 30 and 32 and associated conductors 29 , 31 and 33 are preferably formed on one side of the flexible, resilient material of array 12 . However, the electrodes and conductors may also be formed separately from the array 12 and individually placed on the array 12 in a necessary configuration and location.
[0025] The conductors 31 and 33 extend from each of the electrodes along the arms 26 and are connected, along with conductor 29 , to a connector 34 disposed on the central body 20 . The connector 34 is used to connect the cable 16 to the electrode array 12 and is formed as one half of a conventional electrical connection, such as a male or female plug portion. Preferably, the connector 34 is formed as a female plug portion including an aperture (not shown) for the reception of a male plug portion (not shown) located on the end of the cable 16 extending away from monitor 14 . The aperture exposes the end of each of the conductors 29 , 31 and 33 leading from the electrodes 28 , 30 and 32 , respectively, such that the plug can contact the conductors and receive a biopotential signal transmitted by the conductors 29 , 31 and 33 from the electrodes 28 , 30 and 32 , respectively, for transmission along the cable 16 to the monitor 14 .
[0026] The array 12 also includes adhesive material 40 disposed on each of the central body 20 and side bodies 22 and 24 , around the electrodes 28 , 30 and 32 . The material 40 functions to secure the array 12 and each electrode 28 , 30 and 32 against the skin of the forehead 18 of the subject so that biopotential signals from the forehead 18 can be picked up by the electrodes 28 , 30 and 32 . The material 40 also prevents the movement of the array 12 and electrodes 28 , 30 and 32 with respect to the forehead 18 to insure the electrodes remain in optimal locations on the forehead 18 for picking up the desired signals from the brain or head. The overall construction of the array 12 enables the array 12 to be disposed of in its entirety after use for measuring biopotential signals from the forehead 18 of a subject.
[0027] Referring now to FIGS. 1 and 3, the monitor 14 receives the signals picked up from the subject's head 18 by the electrodes 28 , 30 and 32 via the cable 16 . The cable 16 includes three input signal leads 42 , 44 and 46 which extend along the cable 16 and each correspond to and connect with one of the conductors 29 , 31 or 33 in the connector 34 via the male plug portion. At the end of cable 16 , opposite the male plug portion, each lead 42 , 44 and 46 is connected into a set of nodes 48 , 50 and 52 , respectively. The nodes 48 , 50 and 52 form part of a switching arrangement 54 which includes three switches 56 , 58 and 60 . Each switch 56 , 58 and 60 is associated with one set of nodes 48 , 50 and 52 , respectively, such that each switch can selectively contact each of the three nodes in each set. The switches are shown schematically in the drawing for illustrative purposes and may comprise solid state switching elements or other suitable components.
[0028] The outputs of switches 56 , 58 and 60 are connected to the inputs of a signal processing unit, shown as differential amplifier 62 which amplifies the biopotential signals transmitted from the leads 42 , 44 and 46 . For a signal processing unit comprising a differential amplifier, the output of switch 56 is connected to a positive signal input 64 of amplifier 62 , the output of switch 58 is connected to a negative signal input 66 , and the output of switch 60 is connected to a ground input 68 via ground 63 . The signals transmitted to the positive signal input 64 and negative signal input 66 are used to establish a signal difference that is amplified by the differential amplifier 62 to create an output signal in conductor 70 which is processed and used to drive a display 72 for the monitor 14 .
[0029] The monitor 14 also includes a plurality of buttons 74 a, b, c, and d disposed on monitor 14 . The buttons 74 are operably engaged with the switching arrangement 54 and are used to control the configuration of the switches 56 , 58 and 60 in order to alter the connections between the signal leads 42 , 44 , and 46 and amplifier 62 . For EEG signals, this obtains various EEG measurements from the signals from the frontal cortex of the subject's forehead 18 or different sections thereof, which are displayed on the monitor 14 .
[0030] To operate system 10 , the cable 16 is connected to the electrode array 12 which is positioned on the subject's forehead 18 with each electrode 28 , 30 and 32 in a desired location and secured to the patient's forehead by the adhesive material 40 . By operating one of the buttons 74 a, b, or c, the user selects the configuration of the switches 56 , 58 and 60 within the monitor 14 . The configuration of the switches determines how the biopotential signals obtained by the electrodes 28 , 30 and 32 from the subject's forehead 18 will be utilized by differential amplifier 62 . For example, when the switches 56 , 58 and 60 are in the configuration shown in FIG. 3, the signal from the electrode 30 is utilized as the positive signal input 64 , the signal from the electrode 28 is utilized as the negative signal input 66 , and the signal from the electrode 32 is utilized as the ground input 68 . For EEG signals, this would measure the biopotential signal existing in one of the hemispheres of the patient's forebrain, i.e. the right hemisphere shown in FIGS. 1 and 2. By operating a different button 74 , the configuration of the switches 56 , 58 and 60 will change such that signals from different electrodes 28 , 30 and 32 will be utilized as the positive signal input 64 , negative signal input 66 and ground input 68 for the amplifier 62 to measure the biopotential signal existing in the other forebrain hemisphere or in the overall frontal cortex of the brain. Thus by changing the configuration of the switches with buttons 74 a, 74 b, or 74 c, and hence the inputs to differential amplifier 62 , a user can determine the neurological activity in the right hemisphere of the forebrain, in the left hemisphere of the forebrain, or in the overall frontal cortex pursuant to an EEG measurement performed in the conventional 1-channel mode of the system 10 .
[0031] Further, monitor 14 can contain a control 76 such that when button 74 d is operated, a computer program or other control element, is initiated to periodically alternate the configuration of the switches 56 , 58 and 60 in a specified manner. This allows the monitor 14 and system 10 to alternately measure the neurological activity in each hemisphere of the forebrain to obtain a measurement similar to that of a 2-channel EEG measurement mode. Thus, the system 10 can be selectively operated in either a selected 1-channel or 2-channel surrogate measurement mode simply by operating the appropriate button 74 on the monitor 14 associated with the desired measurement mode.
[0032] Operation of system 10 to obtain EMG biopotential signals is carried out in a manner analogous to that described above in connection with obtaining EEG signals.
[0033] By sensing properties such as the signal strength and/or signal noise in conductors 42 , 44 , and 46 , as by signal sensor 78 and connection 80 , control 76 can be used to provide signals of highest quality to differential amplifier 62 , thereby to improve the quality of the output signal in conductor 70 . Signal sensor 78 may also be used to provide and indication of the status of the electrodes of array 12 .
[0034] Various alternatives are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention. | A configurable system for obtaining a measurement of activity producing biopotentials in a subject, for example EEG or EMG biopotentials. The system includes a three electrode array positionable on the head of the patient to detect signals generated in the head of the subject. The array is connected to a monitor that includes a switch arrangement that is selectively configurable to direct the incoming signals received by the electrode array to specified inputs of a differential amplifier that creates signals that are displayed on the monitor. The switch arrangement is configurable to measure the activity of the subject in a conventional 1-channel measurement mode. The switch arrangement can also be configured to simulate a 2-channel measurement mode by alternating the configuration of the switch arrangement in a pre-determined manner. | 8 |
This is a continuation of application Ser. No. 067,781 filed Aug. 20, 1979 now abandoned.
BACKGROUND OF THE INVENTION
In U.S. Pat. No. 4,067,477 issued Jan. 10, 1978 to Jack S. Chalabian, for a SINGLE ARTICLE VENDING MACHINE, there is described a vending machine of the type used for vending newspapers and like articles, and including means to prevent more than one article from being removed from the machine each time the access door is opened by depositing certain coins into the machine. The disclosure of U.S. Pat. No. 4,067,477 is incorporated by reference into the present specification, and an understanding of U.S. Pat. No. 4,067,477 is deemed essential for a full understanding of the present specification. The present specification discloses a number of improvements to the single article vending machine disclosed in U.S. Pat. No. 4,067,477. In view of the extensive discussion of the background and structure of the single article vending machine given in U.S. Pat. No. 4,067,477, it will not be necessary to repeat that information here, and the discussion in the present specification will embrace mainly the improvements in the machine.
SUMMARY OF THE INVENTION
In the single article vending machine disclosed in U.S. Pat. No. 4,067,477, a stack of newspapers or similar articles was stored on a vertically-movable spring-loaded platform, which urged the stack of articles upward against the underside of a protective cover located within the machine. It was found to be possible to defeat that machine, once the access door had been opened, by reaching into the machine and depressing the platform, and then manipulating the topmost article in the stack sidewardly and upwardly around the side of the protective cover. This mode of theft was relatively uncommon in practice because of the time and dexterity required. Nevertheless, this mode of theft has been eliminated in the improved vending machine of the present invention by the provision of means to prevent downward motion of the platform while the machine is vending the article. The means to prevent downward motion of the platform are enabled by an operator after he finishes servicing the machine and replenishing the supply of articles in the machine. Although a ratchet having a pawl enabled by the operator could be used to limit the platform motion to the upward direction, in a preferred embodiment of the present invention, the desired result is accomplished by the provision of an angled catch which is enabled by a catch bar actuated when certain protective lids at the front of the protective cover are closed by the operator when he finishes servicing the machine. Normally, such lids are locked in a closed position, and this results in the catch bar remaining enabled until the machine is serviced again.
In the single article vending machine described in U.S. Pat. No. 4,067,477, the article nearest the cover is removable from the stack through an adjustable opening bounded above by the generally planar lower face of the protective cover and bounded below by an upper wall of a vertically-movable and lockable slide block. As disclosed in U.S. Pat. No. 4,067,477, the slide block is moved vertically to adjust the height of the opening by rotating captive screws which engage threaded openings of the upper wall of the slide block. After the vertical height of the opening has been thus adjusted, the captive screws are locked in rotation and thereafter protected from tampering by the protective lid referred to above.
In the unimproved machine, the upper wall of the slide block always remained suspended on the adjusting screws at the lowest possible position consistent with the extent to which the adjusting screw had been rotated. In order to adjust the height of the opening, it was necessary to rotate the adjusting screws to lower the upper wall of the slide block by an amount ample to permit the topmost article to be drawn by the operator into the adjustable opening. Thereafter, the adjusting screws were rotated to draw the upper wall of the slide block upwardly and into contact with the underside of the topmost article within the opening. An adjusting screw was provided at each end of the slide block, and it was difficult to be certain that the opening was adequate at each side to pass the article without squeezing it excessively. Because newspapers are folded at one edge, the opening would ideally be slightly larger at that end than at the other end.
Means are provided in the present invention to facilitate adjustment of the opening. In a preferred embodiment, this is accomplished by the use of a compression spring beneath the upper wall of the slide block, which urges the upper wall of the slide block against the underside of the uppermost article after it has been drawn into the opening. The proper height of the opening is thus established with the proper degree of squeezing of the article at each end of the slide block. Because the adjusting screw engages a threaded opening in the upper wall of the slide block, as the upper wall is driven upwardly by the aforesaid springs, the adjustment screw is pushed upwardly through a clearance hole in the protective cover. Thereafter, the adjustment screw is rotated until the bottom side of the head of the screw is flush with the surface of the protective cover. At that point, the height of the opening has been adjusted, and the adjusting screws are locked in position. After the topmost article has been withdrawn through the opening, upward movement of the adjusting screw above the protective cover is prevented by closure of a protective lid by the operator at the time he services the machine. In use, after the operator has loaded a stack of articles into the vending machine, he then depresses the upper wall of the slide block and pulls the uppermost article forward so as to protrude into the opening. He then releases the upper wall of the slide block which is urged upwardly against the protruding article by the springs, thereby establishing the height of the opening. Thereafter, the operator locks the slide block at the thus-determined position.
A number of improvements have been made to the protective cover of the vending machine to enable it to operate more smoothly and dependably, and particularly to facilitate withdrawal of the uppermost article in the stack, and to reduce the risk that the uppermost article might become skewed as it is being removed. A roller has been provided on the protective cover, and the axis of the roller is perpendicular to the direction in which the articles are removed, while a portion of the cylindrical surface of the roller extends slightly below the underside of the protective cover to provide a rolling contact between the uppermost article and the roller.
In accordance with the present invention, a guide flange is provided on the right end and on the left end of the protective cover. These guide flanges extend downwardly from the underside of the protective cover adjacent the right and left ends of the topmost article, and extend parallel to the direction in which the article is withdrawn to prevent the article from becoming skewed as it is withdrawn. The above-mentioned roller tends to cause the uppermost article to move preferentially in a direction perpendicular to the axis of the roller as the article is withdrawn; thus, the roller and the guide flanges cooperatively coact with the article to prevent it from becoming skewed.
In the unimproved vending machine disclosed in U.S. Pat. No. 4,067,477, the display cabinet included mounting brackets having a slot through which a rod extending across the rear of the protective cover and projecting beyond the left and right ends of the protective cover would fit to position the cover within the display cabinet and to prevent forward motion of the protective cover. In the unimproved version, the slot opened to the top and thereafter extended forward within the brackets. Some operators, it was found, became careless and failed to insert the rod properly into the slot. This difficulty is overcome in the present invention by the provision of a mounting bracket having a tapered slot which opens to the front and which extends rearwardly in the mounting bracket. In the present invention, forward motion of the protective cover is prevented by the interaction of portions of the cover with other structural elements of the vending machine. For this reason, the cover is inserted into the vending machine with the front end of the cover inclined above the rear end of the cover, the rods or pins are then inserted into the slots by the operator, and thereafter, the front part of the protective cover is lowered onto the stack of articles.
The novel features which are believed to be characteristic of the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the improved machine of the present invention;
FIG. 2 is a cross-sectional top view showing the protective cover of the present invention;
FIG. 3 is a side cross-sectional view in the direction 3--3 indicated in FIG. 2;
FIG. 4 is a bottom view showing the underside of the protective cover in a preferred embodiment;
FIG. 5 is an elevation view partially in cross section in the direction 5--5 indicated in FIG. 2;
FIG. 6 is a side elevation view partially in cross-section showing the locking assembly immediately after the access door has been opened and prior to the withdrawal of the uppermost article;
FIG. 7 is a side elevational view partially in cross section showing the configuration of the locking assembly as the uppermost article is being withdrawn;
FIG. 8 is a side elevational view partially in cross section showing the locking assembly in its locked configuration after the uppermost article has been withdrawn;
FIG. 9 is a side elevational view showing the configuration of the locking assembly as the mechanism is being cocked by opening the access door of the vending machine;
FIG. 10 is a side elevational view partially in cross-section showing the cocking mechanism; and,
FIG. 11 is a side elevational view showing the mechanism for preventing depression of the platform.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings, in which like parts are denoted by the same reference numeral throughout, there is shown in FIG. 1 a perspective view of the improved single article vending machine of the present invention. As seen in FIG. 1, the vending machine includes a housing 12 which protects the articles from the weather and which provides means to limit access to the articles. An access door 14 is provided in the housing 12, but the access door 14 remains locked until a predetermined combination of coins has been inserted into the coin slots 16. After opening the access door 14, the customer raises the handle 18, thereby revealing a portion of one of the articles, which the customer then draws forward from underneath the protective cover 20. As will be described below, the improved single article vending machine of the present invention includes means to prevent the customer from removing more than one article once the access door 14 has been opened.
FIG. 2 is a top view in cross section and partially cut away showing the protective cover 20 installed within the housing 12, while FIG. 4 is a bottom view of the protective cover 20, in a preferred embodiment.
As seen in FIGS. 2 and 4, the protective cover 20 includes a transparent window 22 which permits a portion of one of the vended articles to be seen, even though the articles lie beneath the protective cover 20.
The protective cover 20 further includes a roller 24 disposed in the protective cover 20 with its axis parallel to the plane of the cover and perpendicular to the direction in which the articles are withdrawn. The diameter of the roller 24 is sufficiently large that its cylindrical outer surface extends slightly below the lower surface of the transparent window 22, as shown in FIG. 6, so that as each of the articles is withdrawn from the machine it passes in contact over the cylindrical surface of the roller which thereby provides a rolling contact between the article and the protective cover 20 to facilitate withdrawal of the article from the vending machine.
Withdrawal of the articles from the vending machine is further facilitated by the provision of a facing 26 of low-friction material on the underside of the protective cover at its front portion. In a preferred embodiment, this facing may be of a plastic or teflon material.
A guide flange 28 is provided at each side of the protective cover 20 to insure that the articles do not become skewed or caught in the machine as they are being withdrawn. The guide flanges 28 are attached to the arms 30 and extend downward from the protective cover 20 toward the stack of articles and lie adjacent the right and left ends of the article nearest the cover.
Each of the arms 30 is provided at its rear portion with a pin 32 which extends laterally outwardly from the arm 30. Each pin 32 fits into a mounting bracket 34 which is affixed to the housing 12 of the machine.
When the machine has been serviced, that is, when a stack of articles has been loaded into the vending machine, the protective cover is inserted into place in the manner shown in FIG. 3. That is, the protective cover is moved downwardly toward the mounting bracket 34 so that the pins 32 will enter the slots in the mounting bracket. As seen in FIG. 3, the mounting bracket 34 includes a portion 38 defining a slot which extends frontwardly and upwardly and opens toward the front of the machine. This is a practical improvement over the type of slot used in an earlier version of the vending machine. Each of the pins 32 is provided with an enlarged head 36 which prevents the pin from moving laterally out of the slot. As seen in FIGS. 2 and 3, a portion 40 of mounting bracket 34 is angled to facilitate insertion of the pin 32 into the slot.
FIGS. 5-10 show the locking mechanism employed in the preferred embodiment of the improved single article vending machine. FIG. 5 is a front view taken in the direction indicated in FIG. 2 and corresponding generally to FIG. 3 of U.S. Pat. No. 4,067,477. FIG. 10 of the present disclosure shows the mechanism for cocking the locking apparatus and corresponds generally to FIG. 4 of U.S. Pat. No. 4,067,477. FIGS. 6-9 of the present disclosure show successive stages in the operation of the locking mechanism, and FIGS. 6-8 of the present disclosure correspond respectively to FIGS. 6-8 of U.S. Pat. No. 4,067,477. These correspondences are mentioned, not to suggest a high degree of similitude, but rather to facilitate identification of the salient differences which are the improvements of the present invention.
Referring now to FIG. 10 of the present disclosure, the locking mechanism is cocked as the access door 14 is opened. This is accomplished through the use of an actuating lever 42 which is pivotally mounted to the access door 14 in the manner shown in FIG. 4 of U.S. Pat. No. 4,067,477. The lower end of the actuating lever 42 includes a slot 44 which engages a roller pin 46 that extends to the right from the wheel 48. As the access door 14 is opened, the longitudinal axis of the actuating lever 42 moves from a first position 50 to a second position 52, causing the wheel 48 to rotate in the counterclockwise sense indicated by the arrows. Mounted on the opposite side of the wheel 48 from the pin 46 is a roller pin 54 which extends leftwardly from the wheel 48. As the access door 14 is opened, rotation of the wheel 48 causes the second pin 54 to drive the lever 56 in the clockwise sense as indicated in FIG. 10. The lever 56 is in face-to-face contact with a second lever 59 which is rigidly fixed to the square shaft 58; the lever 56 includes a circular hole 53 which permits the lever 56 to rotate about the square shaft 58. The lever 56 further includes a leftwardly protruding portion extending from the edge 57 so that as the lever 56 is rotated in the clockwise sense, it effects clockwise rotation of the underlying lever 59 and with it the square shaft 58. During this clockwise rotation of the lever 56, the pin 54 initially bears against the edge 57, but at a later stage of the rotation, the pin 54 clears the end 61 of the lever 56. At this point, the springs 62 shown in FIG. 5 bias the lever 56 in the counterclockwise sense causing the lever 56 to be rotated by the lever 59 in the counterclockwise sense to approximately the position shown in FIG. 10, and during this return motion, the pin 54 bears against the edge 55 of the lever 56. During this return motion as the access door 14 is being closed, the pin 54 moves distally along the edge 55 and eventually passes around the end 61 of the lever 56. Once the pin 54 has cleared the end 61, the crank 60 pushes the lever 56 in the clockwise sense so that the pin 54 will return to its initial position at which it bears against the edge 57. During a portion of the return stroke, the lever 56 is driven in the counterclockwise sense relative to the underlying lever 59 by the pin 54. Such motion is possible because the edge 55 does not include a leftwardly extending portion of the type provided on the edge 57. Thus, the lever 56 in association with the lever 59 acts to drive the shaft 58 in the clockwise sense but does not torque the shaft 58 in the counterclockwise sense during the return movement. Each time the access door 14 is opened, the shaft 58 is forcibly rotated in the clockwise sense and this cocks the locking spring 64 shown in FIG. 5. The cocking action of the locking mechanism will now be discussed in connection with FIG. 9, which, as indicated in FIG. 5, is a view looking toward the right end of the machine, so that the clockwise rotation of the shaft 58 shown in FIG. 10 is shown as a counterclockwise rotation in FIG. 9.
As shown in FIG. 9, rotation of the shaft 58 in the counterclockwise sense causes the toggle lever 66, which is rigidly affixed to the shaft 58, to draw the rod 68 downwardly, thereby stretching the locking spring 64 (shown in FIG. 5). This same motion of the rod 68 also pulls the locking finger 70 downward. The catch 72 is spring-biased in the counterclockwise sense as shown in FIG. 9. As the rod 68 is moved downwardly by the toggle lever 66, the rod impinges on the sloping edge 74 of the catch 72 driving the catch 72 in a clockwise sense against the urging of the biasing spring 108. At a still later stage in the downward motion of the rod 68, the rod clears the edge 76 of the catch 72, which then moves under the action of the biasing spring in a counterclockwise sense to pass above the rod 68, thereby capturing it and thereby holding the springs 64 in their extended condition.
The lock lever 78 is pivotally connected to the rod 68, and during the cocking stroke, the arm 80, which is rigidly affixed to the shaft 58, pulls the lower end of the lock lever 78 toward the right as seen in FIG. 9, to clear the lock rod 82. At the end of the cocking stroke, the parts of the locking mechanism are disposed as shown in FIG. 6.
As shown in FIG. 6, the rod 68 is held in the cocked position by the edge 76 of the catch 72, thereby holding the locking fingers 70 in a retracted position as shown in FIG. 6.
As shown in FIG. 6, an adjustable opening 84 is bounded at its upper side by a generally planar lower surface 86 of the protective cover 20, and bounded on its lower side by an upper wall 88 of the vertically-movable and lockable slide block 92. The uppermost article to be vented is removed from the machine through the adjustable opening 84.
As shown in FIG. 6, stop members 100 extend into the adjustable opening 84 and come in contact with the article when it is pulled into the opening 84. The stop members 100 are pivotally mounted to the rod 94 which, in turn, is supported by the fixed mounting bracket 96 attached to the fixed wall 98.
The stop member 100 is pivotally connected to the catch 72 by the connecting rod 102. Rotation of the top portion of the stop member 100 in the counterclockwise sense in FIG. 6 is prevented by interaction of the catch 72 with the rod 68. Pivotal motion of the stop member 100 in the clockwise sense is produced as the article 90 is pulled through the opening 84. This clockwise motion of the stop member 100 pushes the connecting rod 102 downwardly, causing the catch 72 to pivot in the clockwise sense about the lock rod 82, thereby releasing the rod 68 so that it can move upwardly, propelling the locking finger 70 upwardly. The resulting configuration of the parts is shown in FIG. 7. It is noted that the top end of the locking finger 70 contacts the underside of the article 90 being withdrawn from the machine, and is urged upwardly against the underside of the article by the spring 64.
It should also be noted that as shown in FIG. 7, the lock lever 78 has been pulled vertically upwardly by the upward movement of the rod 68 and that the sloping lower edge 104 of the lock lever 78 cams the lock rod 82 toward the left in FIG. 7 within the slot 106 and against the rightward urging of the spring 108.
After the trailing edge of the article 90 has passed the top portion of the locking finger 70, the still upwardly urged locking finger 70 moves into the adjustable opening 84 and contacts the lower surface 86 of the protective cover 20, as shown in FIG. 8. The stop member 100 is returned to the position of FIG. 6 by the urging of the spring 108, which also urges the lock rod 82 rightwardly within the slot 106.
The incremental vertical movement of the locking fingers 70 between the position shown in FIG. 7 and the position shown in FIG. 8 is sufficient to permit the end 110 of the lock lever 78 to clear the rod 82 vertically. The rightward movement of the rod 82 within the slot 106 between the position shown in FIG. 7 and the position shown in FIG. 8 insures that the edge 112 instead of the edge 104 will contact the rod 82 in the event an effort were made to push the locking fingers 70 downwardly. This insures that the locking fingers 70 cannot be removed from the adjustable opening 84 by the customer, and the presence of the locking fingers 70 extending across the adjustable opening 84 prevents removal of a second article 91 from the machine. Thereafter, the uppermost article in the stack can be removed only by closing the access door 14, depositing the correct combination of coins into the coin slots 16, and again opening the access door 14 to return the locking mechanism to the cocked condition shown in FIG. 9.
In a preferred embodiment of the present invention, compression springs 114 of FIG. 5 are provided to urge upwardly the vertically movable upper wall 88 of the slide block against the underside of an article which has been drawn into the adjustable opening 84 in the manner shown in FIGS. 6 and 7. The adjustment screws 116 engage threaded holes in the upper wall 88 of the slide block, and pass through a clearance hole 118 in the lower portion of the protective cover 20. Thus, the adjustment screws 116 are pushed upwardly through the clearance hole 118 and must then be rotated to move them downwardly until the bottom side of the head of each of the adjustment screws is flush with the surface of the protective cover. At that point, the vertical height of the adjustable opening 84 has been adjusted, and therefore further rotation of the adjustment screws 116 is prevented by inserting the rods 120 into one of several horizontally directed holes 122 in the heads of the adjustment screws. After the topmost article has been withdrawn through the opening 84, upward movement of the adjusting screws 116 is prevented by contact with the lid 124 which was closed and locked by the operator at the time he serviced the machine.
In servicing the machine, the operator places a stack of articles into the machine on the vertically movable platform 126 shown in FIG. 11. Thereafter, the operator depresses the upper wall of the slide block and pulls the uppermost article forward so that it protrudes into the adjustable opening 84 in the manner shown in FIG. 6. The operator then releases the upper wall 88 of the slide block which is then urged upwardly by the springs 114 of FIG. 5 against the protruding article, thereby establishing the vertical height of the adjustable opening 84. The operator then rotates the adjustment screws 116 until they are flush with the protective cover, and then the operator inserts the rods 120 into the holes 122 of the adjustment screws 116 to prevent further rotation. Finally, the operator closes the lids 124 and locks them to prevent tampering. When the access door 14 is then closed, the machine is ready for use by the customers.
It was found to be possible, in theory at least, to defeat the unimproved single article vending machine disclosed in U.S. Pat. No. 4,067,477. Although considerable dexterity, as well as time, are required, it is possible, once the access door has been opened, to reach into the vending machine and to depress the platform 126 of FIG. 11, and then to manipulate the uppermost article in the stack sidewardly and upwardly around the side of the protective cover, thereby to remove the article from beneath the cover. This mode of theft has been eliminated in the improved single article vending machine disclosed herein by the means shown in FIG. 11.
The stack of articles to be vended rests inside the vending machine on a spring-loaded platform 126 which assures that the stack is urged upwardly against the underside of the protective cover 20 regardless of how many newspapers are included in the stack at any particular time. The platform 126 is mounted for vertical movement on the rod 128. An angled catch 130 is pivotally attached to the platform 126 by a mounting bracket 132. The mounting bracket 132 includes a horizontally elongated slot 134 within which a pin 136 extending horizontally from the angled catch moves in the frontward and backward directions. The pin 136 is affixed to the angled catch 130, rather than to the mounting bracket 132.
The angled catch 130 shown in cross section in FIG. 11, has a generally U-shaped cross section including two vertically extending sidewalls 138 and a base 140. The base 140 includes a hole 142 of sufficient diameter to pass the rod 128, but not appreciably larger.
As the platform 126 is moved upwardly, the angled catch 130 is required to move upwardly with it. During such upward movement, any friction between the rod 128 and the edges of the hole 142 will tend to rotate the angled catch 130 in a counterclockwise sense, which will increase the projected cross section of the hole 142 in the direction of motion, thereby resulting in a reduction of such frictional forces. However, an attempted downward motion of the platform 126 will cause any friction between the walls of the hole 142 and the rod 128 to be amplified by virtue of the tendency of the angled catch 130 to be rotated in the clockwise sense, thereby reducing the projected cross sectional area of the hole 142 in the direction of motion. Thus, downward motion of the platform 126 causes the angled catch 130 to grip the rod 128 more tightly, thereby resisting the downward motion. The direction of the forces brought into play is such that the pin 136 is driven to the right end of the slot 134 when downward motion of the platform is attempted.
Downward motion of the platform is desired when the vending machine is serviced, and this is accomplished by the catch bar 144 which is typically mounted on the housing of the vending machine and which is spring-loaded so as to move up, when the lid 124 is raised, from the position shown in FIG. 11 in solid lines to the position shown by the dashed lines. In so moving, the catch bar 144 strikes the right hand end of the angled catch 130 driving the angled catch leftward in the slot 134 and pivoting the angled catch 130 in a counterclockwise sense about the pin 136. Both of these effects loosen the grip of the angled catch 130 on the rod 128, permitting the platform 126 to be lowered by the addition of more articles to be vended. A torsion spring 137 applies a gentle bias to the angled catch 130 in the clockwise sense to insure contact between the edge of the hole 142 and the rod 138 after the lie 124 has been closed again.
Thus, there has been described an improved single article vending machine which operates more smoothly and reliably and which includes additional anti-theft features. The foregoing detailed description illustrates a preferred embodiment of the invention, and it is to be understood that additional embodiments will be obvious to those skilled in the art. The embodiments described herein, together with those additional embodiments, are considered to be within the scope of the invention. | A number of improvements to the single article vending machine of U.S. Pat. No. 4,067,477 are disclosed. An angled catch has been provided to prevent the platform which holds the articles from being depressed by a customer, thereby defeating one mode of theft. The provision of a biasing spring greatly facilitates the adjustment of the width of the slot through which the articles are withdrawn. Other improvements enable the machine to operate more smoothly and dependably by insuring that the vended articles are withdrawn easily from the machine and without becoming skewed or jammed in the slot. An improved mounting bracket facilitates proper mounting of the protective cover plate by the operator after the machine has been serviced. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 60/227,986, filed Aug. 25, 2000, incorporated herein by reference in its entirety.
STATEMENT AS TO FEDERALLY SPONSORED RESEARCH
This invention was made with Government support under Grant 285285 awarded by the National Institutes of Health and under Grant BE9800617 awarded by the National Science Foundation. The Government may have certain rights in the invention.
FIELD OF THE INVENTION
The invention relates to methods and compositions for purifying and concentrating viruses.
BACKGROUND OF THE INVENTION
Gene therapy involves the transfer of genetic material encoding one or more therapeutic genes and the sequences necessary for their expression to target cells to alter their genetic makeup for some desired therapeutic effect. Gene therapy is being tested in a wide variety of applications, including the treatment of complex genetic disorders such as cancer and infectious diseases such as AIDS, and in tissue engineering. Often, the genetic material is transferred ex vivo to tissue that has been removed from a patient. After gene transfer, the tissue is cultured and expanded in vitro, and then re-implanted into the patient. If the target tissue cannot be removed or cultured in vitro (e.g., brain, heart, lungs), the genetic material is instead injected directly into the patient.
Recombinant retroviruses are the most common gene transfer vector used in human gene therapy clinical trials. However, transduction efficiency is often too low to achieve the desired biological effect in many potential human gene therapy situations. Attempts to improve transduction efficiency by concentrating the retroviruses (e.g., by centrifugation, ultrafiltration, tangential flow, or hollow fiber filtration) have not been very successful. Although retrovirus preparations concentrated by these methods contain higher concentrations of infectious virus, they nonetheless do not transduce significantly more target cells than the unconcentrated stocks. The development of methods that improve transduction efficiency is therefore necessary.
Methods for increasing the sensitivity of assays used to detect disease-causing viruses are also needed. The number of viral particles in a patient's tissue (i.e., viral load) generally correlates well with the rate of progression of associated diseases. To obtain earlier and more accurate diagnoses, and thereby improve patient prognosis, medical personnel need to be able to detect lower viral loads than can be detected with the analytical methods that are currently in widespread use.
SUMMARY OF THE INVENTION
The invention provides new methods for purifying and concentrating viruses. The inventors have discovered that one reason that concentration of retroviruses by the methods described above has not been successful is that high molecular weight proteoglycans present in retroviral stocks are co-concentrated with retroviruses (Le Doux et al., Biotechnology and Bioengineering , 58(1):23-34, 1998). The co-concentrated proteoglycans inhibit retroviral transduction. The new purification and concentration methods feature treatment of virus stock with an anionic polyelectrolyte and a cationic polyelectrolyte, followed by centrifugation. The new methods minimize the amount of proteoglycan co-precipitated with the infectious virus.
In general, the invention features a method for purifying viruses from solution (e.g., solutions containing viruses and other components such as proteoglycans). The method includes the steps of (a) combining the solution with an anionic polyelectrolyte; (b) combining the solution with a cationic polyelectrolyte; and (c) centrifuging the solution to obtain a supernatant and a virus-containing pellet. Steps (a) and (b) can be carried out in forward or reverse order, or simultaneously.
The anionic polyelectrolyte can include, for example, a glycosaminoglycan or a polysaccharide, either of which may be sulfated. Examples include chondroitin sulfates, heparin, heparan sulfate, keratan sulfate, carrageenans, fucoidan, poly-L-glutamic acid, poly-L-aspartic acid, other anionic peptides or proteins, poly(glycolic acid), poly(lactic acid), poly(lactic-co-glycolic acid).
The cationic polyelectrolyte can include, for example, a cationic polymer that complexes with the anionic polyelectrolyte. For example, the cationic polyelectrolyte can be (diethylamino)ethyl dextran, a histone, protamine, poly-L-arginine, poly-L-histidine, poly-L-lysine, or another cationic peptide or protein.
The methods can also include the step of separating the pellet from the supernatant, and then resuspending the pellet in a resuspension buffer (e.g., phosphate buffered saline, cell culture medium, or a buffer suitable for injection into a patient (e.g., a pharmaceutically acceptable carrier such as a solution that does not cause allergic or other adverse reaction with the patient upon injection), for example, in a volume of resuspension buffer no greater than one-tenth or one-hundredth the volume of the solution, thereby resulting in at least a ten-fold or one-hundred-fold concentration of the virus, respectively.
The virus to be purified can be, for example, an enveloped virus, such as a lentivirus, Moloney murine leukemia virus (MMLV), herpes simplex virus (HSV), Epstein-Barr virus (EBV), human cytomegalovirus (CMV), an influenza virus, a poxvirus, an alphavirus, or human immunodeficiency virus (HIV) or other retrovirus; or a non-enveloped virus such as an adenovirus, a parvovirus, or a poliovirus.
Another embodiment of the invention features a method for preparing a formulation for administering a nucleic acid molecule to a patient. The method includes the steps of (a) obtaining a solution containing a virus that includes a nucleic acid molecule to be administered to a patient; (b) combining the solution with an anionic polyelectrolyte; (c) combining the solution with a cationic polyelectrolyte; (d) centrifuging the solution to obtain a supernatant and a virus-containing pellet; (e) separating the supernatant from the pellet; and (f) resuspending the pellet in a resuspension buffer suitable for injection into a patient. The method can also include the step of separating the virus from the polyelectrolytes. Steps (a) and (b) can be carried out in forward or reverse order, or simultaneously.
Still another embodiment of the invention features an assay method for detecting the presence of a virus in a sample. The method includes the steps of (a) obtaining a sample to be assayed for the presence of a virus; (b) combining the sample with an anionic polyelectrolyte; (c) combining the sample with a cationic polyelectrolyte; (d) centrifuging the sample to obtain a supernatant and a pellet (where the pellet includes the virus, if any); and (e) assaying the pellet for the presence of the virus. The method can optionally include the step of resuspending the pellet in a buffer solution, and/or the step of separating the virus from the polyelectrolytes. Steps (a) and (b) can be carried out in forward or reverse order, or simultaneously.
Yet another embodiment of the invention features a kit for use in concentrating or purifying viruses. The kit includes a tube of a suitable size and shape for use in a centrifuge;
an anionic polyelectrolyte; and a cationic polyelectrolyte. Optionally, the kit can also include instructions for use. The polyelectrolytes can be supplied in a single tube or in two separate tubes.
The invention provides several advantages. For example, the invention can be scaled up for use in a large-scale manufacturing process. The invention also has many applications in the emerging commercial field of gene therapy that make use of recombinant retroviruses, as well as in any area of research in which cells or tissues are genetically modified using recombinant retroviruses. The methods of the invention can moreover be rapidly performed in a tabletop centrifuge, thus increasing convenience and efficiency and eliminating losses in infectivity due to thermal decay of the viruses.
The new methods advantageously allow rapid concentration and purification of retroviruses without destroying their biological activity and without placing the retroviruses in a solution that is toxic to the target cells to which they will be applied. The invention allows the virus buffer to be rapidly and easily exchanged for a buffer more suitable to the target cells. This can be important where the cell culture medium used to produce virus particles (e.g., DMEM with 10% bovine calf serum) is not suitable for cell types that are potential targets for gene therapy.
The new methods can be used to concentrate viruses to any desired level. The ability to concentrate viruses would substantially improve the effectiveness of many gene therapies, such as those that rely on lentivirus vectors. Lentivirus vectors are of significant interest for use in gene therapy because they can permanently and stably transfer genes into cells and tissues by direct injection in vivo. Lentivirus vectors often fail to achieve the desired therapeutic effect, however, because they have relatively low gene transfer efficiencies and are produced at low titers. Concentrated forms are needed for injection to achieve the desired biological effect. This invention can be used to manufacture stocks of lentivirus vectors that have a high enough concentration to achieve the desired therapeutic effect.
The new methods not only increase transduction efficiency by increasing the concentration of the viruses, they unexpectedly increase transduction by an additional factor of two to three or more beyond the concentration factor, possibly by increasing the encounter frequency of the viruses with the cells.
This invention will also significantly improve the sensitivity of assays designed to detect pathological viruses in large volumes of fluid such as blood or plasma by precipitating the viruses into a small pellet and to a concentration high enough to be detected by current assays. For example, blood or plasma samples can be treated with charged polymers as described above, and the resulting precipitate pelleted and assayed for the presence of pathological viruses. Because the concentration of the pathological viruses would be substantially increased in the pellet, the overall sensitivity of the screening process would be greatly increased, and, as a result, the safety of the tested blood supply improved.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of relative virus concentration, indicated by the concentration of capsid protein p30, in a retrovirus solution before mixing with POLYBRENE® and chondroitin sulfate C (“Before”), in the retrovirus solution after mixing with POLYBRENE® and chondroitin sulfate C (“After”), in the supernatant resulting from centrifuging the retrovirus solution (“SN”), and in a solution resulting from resuspending to original volume in phosphate-buffered saline (PBS) the pellet resulting from centrifuging the retrovirus solution. The y-axis represents optical density at 490 nm (OD 490 ).
FIG. 2 is a plot of the biological activity of viruses taken from the four samples described in FIG. 1 . The y-axis represents virus titer (colony-forming units per milliliter (cfu/ml)).
FIG. 3 is a plot of relative concentration of serum proteins in the four samples described in FIG. 1 , as indicated using a Coomassie Blue Protein Assay. The y-axis represents OD490.
FIG. 4 is a plot of relative cell number (represented by OD 490 on the y-axis) versus concentration of POLYBRENE® used alone (—), chondroitin sulfate C used alone (-□-), and POLYBRENE® and chondroitin sulfate C used at the same time (-●-).
FIG. 5 is a plot of transduction efficiency of viruses taken from the four samples described in FIG. 1 , with the exception that the “Pellet” sample was resuspended to only ⅛ of its original volume. The dotted line represents the expected transduction efficiency corresponding to 8-fold concentration. The y-axis represents BGAL activity virus titer (colony-forming units per milliliter (cfu/ml)).
FIG. 6 is a plot of secreted KGF accumulated in the culture medium of control unmodified fibroblasts (Control unmodified cells, -●-), fibroblasts that have been modified with a standard stock of unconcentrated keratinocyte growth factor (KGF) retrovirus to which POLYBRENE® alone (8 μg/ml) has been added (KGF virus with polybrene, -∘-), and fibroblasts that have been genetically modified with precipitated KGF virus that was resuspended in one-tenth the original volume (10× precipitate of KGF virus, -▾-), as a function of time, as described in Example 5.
DETAILED DESCRIPTION
This invention describes a simple and facile method to rapidly and selectively concentrate retroviruses.
The New Methods
In a typical method of the invention, virus stocks are combined with 1 μg/ml to 100 μg/ml of anionic polyelectrolyte (e.g., chondroitin sulfate C; “CSC”), optionally incubated (e.g., for 10 minutes or longer) at 4° C. to 37° C., and then combined with 1 μg/ml to 100 μg/ml of a cationic polyelectrolyte (e.g., POLYBRENE®-brand hexadimethrine bromide), and optionally incubated (e.g., for 0 to 10 minutes, or longer) at 4° C. to 37° C. Alternatively, the cationic polyelectrolyte can be added before, or at the same time as, the anionic polyelectrolyte. Subsequently, a visible pellet is typically formed by low speed centrifugation (e.g., 10,000 rpm for 5 minutes) in a tabletop centrifuge.
The cell culture supernatant that contains the unpelleted material can be removed and the pellet resuspended in a buffer optimized for the culture and transduction of the target cells. The final concentration of the viruses, and the number of therapeutic gene copies that are ultimately delivered to the target cells, are controlled by the volume of buffer used to resuspend the pellet. The pellet can be, for example, resuspended in a volume that is 10- to 100-fold less than the initial volume of the virus stock, so that the final concentration of the viruses is 10- to 100-fold greater than the concentration of the viruses in the original, unpelleted, virus stock.
To transduce the target cells, the cells can be incubated (e.g., at 37° C. for several hours) with the concentrated virus solution (which also contains the polyelectrolytes). Significantly, the efficiency with which the cells transduced in these experiments is 2- to 3-fold higher than expected based on the increased concentration of the viruses alone, as described in Example 1. In other words, if the virus solution is concentrated 10-fold by this technique, the efficiency with which the cells are transduced is 20- to 30-fold higher than the original, unpelleted, virus stock. This unexpected increase in transduction efficiency is probably due to a higher frequency of encounters between the target cells and the viruses due to sedimentation of viruses complexed with polyelectrolytes. That is, the rate at which the virus complexes precipitate onto the cells may occur at a higher rate than would occur between viruses and cells in the absence of polyelectrolytes.
Viruses that can be concentrated by the new methods include retroviruses (e.g., enveloped retroviruses) such as human immunodeficiency virus (HIV), lentiviruses, and Moloney murine leukemia virus (MMLV). The method can also be used to concentrate other enveloped viruses, including herpes simplex virus (HSV), Epstein-Barr virus (EBV), human cytomegalovirus (CMV), influenza viruses, poxviruses, and alphaviruses; or non-enveloped viruses such as adenoviruses, parvoviruses, or polioviruses. Lentivirus vectors are of special interest, because they are able to transfer genes to cells that are not dividing. This ability can provide a major advantage for in vivo gene therapy. The new methods can be used to provide lentiviruses at high enough concentrations to achieve the desired biological effect.
Use of the New Methods in Gene Therapy Applications
Retroviruses can be raised in packaging cell lines, and then harvested. The new methods should be useful with any packaging cell line, including, for example, ψCRIP, FLYA13, and PHOENIX® amphotropic packaging cell lines. Retroviruses can be harvested as follows: Packaging cell lines are grown to confluence. The cell culture medium is removed and replaced with fresh medium and the cells are incubated at 37° C. After a sufficient time (e.g., about 12, 18, 24, or 30 hours), the cell culture medium is removed, filtered (0.45 μm), and frozen for later use as a virus stock. The virus stocks can be mixed with polyelectrolyte solutions according to the methods of the invention (e.g., to increase transduction efficiencies and/or to rapidly concentrate and purify the virus particles from the cell culture medium in which they were grown). After the viruses are precipitated with the polymers and centrifuged to form a pellet, they can be resuspended in any suitable buffer including phosphate buffered saline (PBS), tris-buffered saline, or basal cell culture medium (e.g., Dulbecco's modified Eagle medium, “DMEM”). Resuspended virus particles can be injected into a tissue to be treated, administered orally, nasally, rectally, intravenously, intramuscularly, using a gene gun or other intradermal methods, or by other routes used for drug delivery. A major advantage of this method is that less than 3 percent of non-viral proteins are precipitated with the virus particles, affording a dramatic reduction in, or elimination of, natural inhibitors of retrovirus transduction such as proteoglycans or TGF-β.
Use of the New Methods in Analytical Applications
Current methods for detecting viruses typically assay blood plasma for the presence of markers for a particular virus. In the case of human immunodeficiency virus, for example, these markers include viral RNA and HIV p24 antigen (a virus capsid protein). Viral RNA has traditionally been the marker of choice, in part because RNA assays can make use of the polymerase chain reaction (PCR) to amplify the analyte and are, therefore, generally more sensitive than the enzyme-linked immunosorbent assays (ELISAs) use to detect the antigens such as HIV p24. Although RNA assays tend to be more sensitive, however, they are also more expensive and are not as easy to perform as ELISAs. Cost and sensitivity issues aside, both types of assays have proved to be valuable predictors for certain aspects of the progression of diseases such as AIDS. RNA assays, for example, appear to be better predictors of the clinical progression of the disease, whereas p24 antigen assays appear to be better predictors of the patient's chance of survival.
The new methods can be used to concentrate viruses present in tissue samples before the samples are analyzed, effectively increasing the sensitivity of the analytical methods. Advantageously, the polymers used for virus precipitation in the new methods do not block the ability of standard protocol assays such as ELISAs to detect retrovirus proteins, and should not interfere with PCR reagents.
Polyelectrolytes
In general, any pair or system of charged polymers that can bind to the viruses or otherwise interact with viruses so as to cause them to aggregate or otherwise precipitate rapidly under low speed centrifugation can be used to concentrate viruses.
Preferably, the charged polymers are not toxic to the cells and do not inactivate the viruses. If the charged polymers are cytotoxic, they must be able to be separated from the viruses prior to their application to the target cells. For example, the virus can be dissociated from the polymers using a high-salt buffer that reduces the electrostatic attraction between the virus and polymers. Alternatively, the virus can be dissociated from the polymers by enzymatically degrading one or both of the polymers. For example, CSC can be degraded into individual disaccharides by treating the solution with chondroitinase ABC. Once the polymers have been degraded or dissociated from the virus, the virus can be isolated (e.g., using a gel filtration spin column).
Chondroitin sulfate C and POLYBRENE® together form an examplary pair of polyelectrolytes that can form complexes that can be used to concentrate viruses. However, any pair of polyelectrolytes that includes an anionic polymer (e.g., sulfated glycosaminoglycans or polysaccharides such as chondroitin sulfate A, B, D, or E, heparin, heparan sulfate, keratan sulfate, iota carrageenan, kappa carrageenan, and fucoidan; anionic peptides and proteins such as poly-L-glutamic acid and poly-L-aspartic acid; or biodegradable polymers such as poly(lactic acid), poly(glutamic acid), and poly(lactic-co-glycolic acid)) and a cationic polymer that can complex with the anionic polymer (e.g., POLYBRENE®, (diethylamino)ethyl dextran (DEAE dextran), histones, protamine, or cationic peptides and proteins such as poly-L-lysine, poly-L-arginine, and poly-L-histidine) can be used instead of this exemplary pair. For example, polymer pairs iota carrageenan and DEAE dextran; heparan sulfate and protamine; and L-glutamate and L-lysine can be used.
Virus Concentration Kits
Optionally, the new methods can be carried out using a reagent kit. The kit can include suitable reagents and optionally vessels for carrying out the new methods. Such a kit can be produced and sold in various sizes. For example, a kit for concentrating small volumes of virus-containing medium (e.g., less than about 25 ml) can include a plastic or glass tube, which can contain a solution of a suitable anionic polymer or into which such a polymer can be added from another supplied vessel. The tube can be, for example, a standard centrifuge tube or a similarly sized and shaped tube. After introducing the virus-containing medium into the tube, the tube can be sealed (e.g., using a supplied screw cap), shaken to ensure thorough mixing, and incubated for a suitable time. After incubating, the tube can be opened and a solution containing a suitable cationic polymer can be added (e.g., using a pipettor) to the tube. The tube can then be re-sealed, shaken, and incubated again. Alternatively, the contents of the tube can be decanted after the first incubation step into a second tube that already contains a suitable cationic polymer. The second tube can likewise be sealed, shaken, and incubated. In either case, the tube can be loaded into a centrifuge (or its contents can be decanted into a centrifuge tube and loaded into a centrifuge) after the second incubation step, and spun at a suitable speed. The supernatant resulting from the centrifugation step can then be decanted, being careful not to disrupt the pellet. The pellet might then be washed using an optionally supplied wash solution, and possibly resuspended in a supplied resuspension buffer.
The kits can optionally include enzymes or small spin columns to eliminate or separate, respectively, the viruses from the polymers. The kits can also include a dye, or the polymers can be conjugated to a dye, to make the precipitated virus easy to see with the naked eye, thereby facilitating the resuspension of small volumes of virus. The kit can also include a resuspension buffer optimized for transducing particular cell types or for injection in vivo.
Numerous other embodiments of suitable kits are also contemplated, including kits for use with both tabletop and larger centrifuges.
EXAMPLES
The invention is further described in the following examples, which do not limit the scope of the invention described in the claims.
Example 1
Concentration of MMLV
Stocks of Moloney murine leukemia virus (MMLV) were brought to 80 μg/ml of chondroitin sulfate C, incubated for 10 minutes at 37° C., and then brought to 80 μg/ml of POLYBRENE®, and incubated for an additional 10 minutes at 37° C. The retroviruses, when mixed with POLYBRENE® and chondroitin sulfate C (CSC), were visibly pelleted by low speed centrifugation (i.e., 10,000 rpm for 5 minutes) in a tabletop centrifuge. The visible pellet was resuspended to its original volume with phospate buffered saline (PBS). As shown in FIG. 1 , the solution resulting from resuspension of the pellet was then tested for the presence of a virus capsid protein (p30) by ELISA (black bar/“Pellet”). The concentration of p30 in the supernatant was determined after centrifugation (cross hatched bar/“SN”), as was the concentration of p30 in non-centrifuged virus stocks before (white bar/“Before”), and after (speckled bar/“After”) POLYBRENE® and CSC were added.
The solution resulting from the resuspension of the pellet in PBS was tested for its biological activity, using a virus titer assay. The pelleted retroviruses were found to have retained most of their biological activity, as illustrated by the black bar (“Pellet”) in FIG. 2 . The biological activity in the supernatant (cross hatched bar/“SN”) was also determined, as was the biological activity in non-centrifuged virus stocks before (white bar/“Before”) and after (speckled bar/“After”) POLYBRENE® and CSC were added.
The solution resulting from the resuspension of the pellet in PBS was tested for total protein concentration. The virus pellets were found to contain very few serum proteins, as illustrated by the black bar (“Pellet”) in FIG. 3 . The total protein concentration in the supernatant (cross hatched bar/“SN”) was also determined, as was the total protein concentration in non-centrifuged virus stocks before (white bar/“Before”) and after (speckled bar/“After”) POLYBRENE® and CSC were added.
As indicated in FIG. 4 , POLYBRENE® and CSC are not cytotoxic when used together. The data plotted in FIG. 4 were determined by adding various concentrations of POLYBRENE® and CSC to culture medium and then applying it to NIH 3T3 cells plated the previous day at 5000 cells per well in a 96 well plate. The cells were grown for two days, and then were fixed and stained in the Orange G assay for cell number.
The results show that virus concentrated by pelleting with POLYBRENE® and CSC efficiently transduces cells. A solution resulting from the resuspension of the pellet to ⅛th its original volume with cell culture medium was used to transduce NIH 3T3 cells. The results are represented by the black bar (“Pellet”) in FIG. 5 . Cells were also transduced with virus stocks before the stocks were centrifuged and before (white bar/“Before”), and after (speckled bar/“After”) POLYBRENE® and CSC were added to them. Cells were also transduced by the supernatant (cross hatched bar/“SN”) of a virus stock after it had been brought to 80 μg/ml POLYBRENE® and 80 μg/ml CSC and centrifuged. Also shown in FIG. 5 is the expected transduction efficiency of a virus stock that is concentrated 8-fold, given that the concentrated virus does not saturate the cells, no inhibitors were co-concentrated with the viruses, and the viruses are not inactivated by the concentration process (dotted line).
In summary, less than 3 percent of non-viral proteins were concentrated into the pellet (FIG. 3 ), giving rise to a pellet that contained active viruses ( FIGS. 2 and 5 ) and the polyelectrolyte complexes but almost no spent medium or other substances that might interfere with retrovirus transduction. Importantly, a solution that contains high concentrations of POLYBRENE® and chondroitin sulfate C is not cytotoxic to cells (FIG. 4 ).
Example 2
Concentration of Lentivirus
The new methods can also be used with lentivirus vectors in a manner similar to that described in Example 1. As described for MMLV in Example 1, stocks of lentiviruses are brought to 80 μg/ml of chondroitin sulfate C, incubated for 10 minutes at 37° C., and then brought to 80 μg/ml of POLYBRENE®, and incubated for an additional 10 minutes at 37° C. The complex of chondroitin sulfate C, POLYBRENE®, and the lentivirus particles is concentrated by low speed centrifugation (e.g., 10,000 rpm for 5 minutes) in a tabletop centrifuge (FIG. 1 ). The pellet is resuspended in phosphate buffered saline or any other buffer suitable for injection in vivo. The volume of the buffer used to resusupend the viruses is chosen based on the desired final concentration of virus needed to achieve a therapeutic effect. Typically, the pellet is resuspended in a volume that is about 10- to 100-fold less than the initial volume of the virus stock, so that the final concentration of the viruses is 10- to 100-fold greater than the concentration of the viruses in the original virus stock. The virus-polymer solution is then delivered in vivo in such a way as to maximize the transfer of genes to the target cells. For example, to target airway epithelial cells, the virus-polymer solution is injected into the lungs of a patient in the form of an aerosol. The number of genes transferred by this method is substantially higher than with traditional methods because the virus is at a higher concentration and the polymer mixture enhances the efficiency of gene transfer 2- to 3-fold or more.
Example 3
Use of the New Methods in Gene Therapy
The new methods are scalable for large-scale purification and concentration of recombinant retroviruses for use in human gene therapy protocols. Large-scale purification and concentration is important for the ultimate success of many human gene therapy protocols because large numbers of genes generally must be transferred to achieve a desired therapeutic effect. It is estimated that up to 1 liter of retrovirus stocks may have to be used for a typical gene therapy clinical trial to achieve the desired effect. To administer this amount of virus to a patient using traditional methods, the patient is treated several times with smaller volumes of virus. The new methods of the invention can be used not only to enhance the activity and concentration of the virus stocks as described in Examples 1 and 2, but also to reduce the number of times the viruses must be administered to patients to achieve the desired therapeutic effect. Large volumes of retroviruses, produced by standard large-scale cell culture techniques (e.g., microcarrier bioreactors or stirred-tank bioreactors), are brought to appropriate concentrations of cationic and anionic polymers as described in Examples 1 and 2. The virus precipitates are then mechanically separated from the fluid portion of the virus stock on a large scale using sedimenting centrifuges and/or centrifugal classifiers. These machines separate particles from fluid streams in a continuous process and allow the new methods to be used on a large scale to produce retrovirus precipitates useful for human gene therapy protocols.
Example 4
Use of the New Methods to Improve Assay Sensitivity
The new methods are also useful for improving the sensitivity of assays designed to detect pathological viruses in blood or plasma. Blood and plasma samples are often screened for the presence of HIV using PCR to detect the RNA genome of HIV or using an ELISA to detect p24, an HIV capsid protein. The number of HIV particles (viral load) in the blood of AIDS patients is often determined in order to follow the course of the disease. The new methods are used to enhance the sensitivity of these assays. Enhanced sensitivity increases the likelihood of detecting blood or plasma products that are contaminated with HIV and reduces the likelihood that a patient is misdiagnosed as HIV negative due to the poor sensitivity of a diagnostic test for HIV. Blood or plasma samples are brought to 80 μg/ml of CSC and POLYBRENE®, and the resulting precipitates are pelleted by low speed centrifugation as described in Example 1. The pellet is resuspended in {fraction (1/10)} to {fraction (1/100)} the original volume, effectively concentrating the HIV antigens 10- to 100-fold. The resuspended sample is tested by any of several currently available ELISA kits that test for the presence of HIV antigens. Because the samples are concentrated 10- to 100-fold, and because the polymers do not interfere with ELISAs, the sensitivity of the HIV test is enhanced 10- to 100-fold. Assuming that the polymers do not interfere with PCR reactions, the sensitivity of kits that detect HIV by PCR is also expected to be enhanced 10- to 100-fold.
Example 5
Precipitation and Concentration of a Recombinant Retrovirus Encoding Keratinocyte Growth Factor (KGF)
The new methods were used to precipitate and concentrate a recombinant retrovirus encoding KGF to improve gene transfer and increase the level of KGF secreted by transduced cells.
A stock of amphotropic KGF retrovirus was harvested from a packaging cell line and filtered through a 0.4 micron filter. The stock was brought to 80 μg/ml CSC and 80 μg/ml POLYBRENE®, and the resulting complex was pelleted by centrifugation and resuspended in cell culture medium to one-tenth the original volume. This 10× concentrated KGF virus suspension was used to transduce human diploid fibroblasts overnight. Afterwards, the cells were washed with culture medium, and then allowed to grow to confluence.
To measure the levels of secreted KGF, the genetically modified human fibroblasts were split into new 10 cm dishes, and grown to confluence. The spent medium was replaced with fresh culture medium (30 ml), and aliquots (1 ml) were removed over time. The levels of KGF secreted by the cells were quantitated using an ELISA specific for KGF. FIG. 6 is a plot of secreted KGF accumulated in the culture medium of control unmodified fibroblasts (Control unmodified cells, -●-), fibroblasts that have been modified with a standard stock of unconcentrated KGF retrovirus to which POLYBRENE® alone (8 μg/ml) has been added (KGF virus with polybrene, -∘-), and fibroblasts that have been genetically modified with precipitated KGF virus that was resuspended in one-tenth the original volume (10× precipitate of KGF virus, -▾-), as a function of time. A small amount of KGF is naturally secreted by control diploid human fibroblasts. As illustrated by FIG. 6 , this level is enhanced when the cells are transduced with the KGF virus in the conventional manner, and is greatly enhanced when the same virus is precipitated with CSC and POLYBRENE® and resuspended in one-tenth the original volume.
Since KGF is known to stimulate the growth of epidermal keratinocytes of the skin, genetically modified cells (e.g., dermis cells, keratinocytes, epidermal cells) secreting KGF may have uses in promoting wound healing (including, for example, healing of chronic wounds such as diabetic wounds). For example, such cells can be administered to tissue in the vicinity of the wound (e.g., by injection or implantation, optionally together with a pharmaceutically acceptable carrier, optionally containing other pharmaceutical substances), or topically applying the cells to the wound (e.g., in a dressing, film (e.g., a polyurethane film), a hydrocolloid (e.g., hydrophilic colloidal particles bound to polyurethane foam), a hydrogel (e.g., cross-linked polymers containing about at least 60% water), a hydrophilic or hydrophobic foam, or another carrier, e.g., a pharmaceutically acceptable gel, cream, powder, suspension, solution, ointment, salve, lotion, or biocompatible matrix, e.g., a petroleum jelly formulation, optionally containing other pharmaceutical substances such as an antibiotic). The cells can be used to promote healing by, for example, stimulating growth of keratinocytes for use, for example, in wound healing methods (e.g., those described in U.S. Pat. No. 6,197,330). Higher levels of KGF secretion can enhance the therapeutic effectiveness of these cells. Higher levels of KGF secretion can enhance the therapeutic effectiveness of these cells.
Other Embodiments
It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. | The invention provides new methods for purifying and concentrating viruses. The inventors have discovered that high molecular weight proteoglycans present in retroviral stocks are co-concentrated with the retroviruses, and can inhibit retroviral transduction. The new purification and concentration methods feature treatment of virus stock with an anionic polyelectrolyte and a cationic polyelectrolyte, followed by centrifugation. The new methods minimize the amount of proteoglycan co-precipitated with the infectious virus. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates to compounds containing a central 1,4,5-trisubstituted 1,2,3-triazole core and a reactive appendage appropriate to form covalent “click” bonds on the surface of materials functionalized with reactive groups including: azide, terminal alkyne, cyclooctalkyne, thiol, maleimide or thiolacid groups and to a process for the preparation of these compounds containing a 1,4,5-trisubstituted 1,2,3-triazole core. These compounds are nonpeptide mimetics of RGD (Arg-Gly-Asp) and/or, OGP 10-14 (Tyr-Gly-Phe-Gly-Gly), osteogenic compounds.
[0002] These compounds are particularly useful for medical devices, including endosseous implants, or tissue engineering scaffold or cell culture matrix, suitable for the replacement or regeneration of human and animal organs.
BACKGROUND OF THE INVENTION
[0003] Some natural short peptides occurring in the extra cellular matrix (ECM) or in serum are useful to enhance the adhesion, viability and proliferation of osteoblast cells.
[0004] RGD occurs in several ECM proteins, including vitronectin, fibronectin and osteopontin. The technological interest in RGD tripeptide analogues in applications related to osteogenesis stems from their ability to regulate the out-in signaling of ECM with integrin receptors in osteoblast cells (Kantlehner M et al. ChemBioChem 2000 1: 107-114 “Surface coating with cyclic RGD peptides stimulates osteoblast adhesion and proliferation as well as bone formation”). Using RGD analogues may be beneficial to regulate bone remodeling by promoting the recruitment, attachment and differentiation of osteoblasts and osteoclasts, as demonstrated for example in osteoporosis therapy (Chen, W. et al in Biotechnol. Lett. 2005 27: 41-48 “Bone loss induced by ovariectomy in rats is prevents by gene transfer of parathyroid hormone or an Arg-Gly-Asp-containing peptide”).
[0005] The osteogenic growth peptide (OGP) is a short naturally occurring 14-mer growth factor peptide found in serum. As a soluble peptide, OGP regulates proliferation, differentiation, and matrix mineralization in osteoblast lineage cells. Studies have demonstrated sensitivity of osteoblast lineage cells to changes in exogenous concentrations of OGP. It has also been shown in the art that only the OGP 10-14 (Tyr-Gly-Phe-Gly-Gly) pentasegment is essential for the osteogenic activity of OGP (Chen, Y.-Ch. et al. J. Med. Chem. 2002 45: 1624-1632 “Bioactive pseudopeptidic analogues and cyclostereoisomers of osteogenic growth peptide C-terminal pentapeptide, OGP 10-14 ”).
[0006] Attaching RGD peptide analogues to the surface of bone or endosseous implants has shown to be beneficial to improve osteoblast cell adhesion (see for example Kessler H et al. Biomaterials 2003 24: 4385-4415 “RGD modified polymers: biomaterials for stimulated cell adhesion and beyond”; see also: Biltresse S. et al. Biomaterials 2005 26: 4576-4587 “Cell adhesive PET membranes by surface grafting of RGD peptidomimetics”). On the other hand, the effectiveness of immobilized OGP to increase osteoblast cell densities and fasten their proliferation rate on OGP-stained materials has been proven “in vitro” (Moore, N. M. et al. Biomaterials 2010 31: 1604-1611 “The use of immobilized osteogenic growth peptide on gradient substrates synthesized via click chemistry to enhance MC3T3-E1 osteoblast proliferation”).
[0007] Natural RGD and OGP peptides, their pseudopeptide cyclic analogues or their amidic surrogates are prone to suffer a fast deactivation by proteolytic cleavage “in vivo”, leading to lowered serum concentrations in systemic applications or inactive surfaces when grafted to biomaterials. Several RGD analogues known in the art may partially overcome this drawback, including some 1,4-disubstituted 1,2,3-triazole compounds (see Trabocchi, A. et al. J. Med. Chem. 2010, 53: 7119-7128 “Click-Chemistry-derived triazole ligands of Arginine-Glycine-Aspartate (RGD) integrins with a broad capacity to inhibit adhesion cells and both in vitro and in vivo angiogenesis” and Ni, M. H. et al Lett. Drug Design & Discovery 2011, 8: 401-405 “Novel RGD peptidomimetics embedding 1,2,3-triazole as central scaffold; synthesis and αvβ3 integrin affinity”). Conversely, some pseudopeptide OGP mimetics are also known in the art (see Bab, I. et al WO9732594A1 “Synthetic peptides and pseudopeptides having osteogenic activity and pharmaceutical compositions containing the same”).
[0008] However, none of these RGD or OGP10-14 nonpeptide mimetics are amenable to embodiments capable to give further “click” attachment to the surface of biomaterials.
[0009] Thus, from what is known in the art, it is derived that the development of a RGD or an OGP10-14 nonpeptide mimetic material capable to attach to the surface of biomaterials is still of great interest.
BRIEF SUMMARY OF THE INVENTION
[0010] Inventors have developed 1,4,5-trisubstituted 1,2,3-triazole compounds mimetics of RGD and/or OGP 10-14 that allow to conduct in a single chemical operation the “click” bonding on the surface of a material. The peptidomimetics bound in this way are stable and do not suffer degradation reactions under physiological conditions.
[0011] Therefore an aspect of the invention relates to a 1,4,5-trisubstituted 1,2,3-triazole compound of formula (I):
[0000]
[0000] wherein:
R 1 is a biradical selected from the group consisting of C 1-20 alkylene; in which 0, 1, 2, 3, 4, 5 or 6 —CH 2 — groups are optionally replaced by groups selected from —O—, —S—, —C(O)O—, —C(O)NH—, —C(O)N(C 1-4 alkyl)-, —NHC(O)NH—, —NHC(O)O—;
R 2 is a biradical independently selected from the group consisting of: C 1-6 alkylene; in which 0, 1, 2 or 3 —CH 2 — groups are optionally replaced by groups selected from —O— and —S—; optionally substituted with one or more groups selected from C 1-4 alkyl, phenyl, C 6-10 aryl; and
R 3 is a biradical selected from the group consisting of: C 1-6 alkylene; optionally containing one or more —C═C— bonds; optionally containing —C≡C— bonds; in which 0, 1, 2 or 3 —CH 2 — groups are optionally replaced by groups selected from —O— and —S—; optionally substituted with one or more groups selected from C 1-4 alkyl, phenyl, —F, —Cl, —OH, —O(C 1-4 alkyl), —S(C 1-4 alkyl), —SO 2 Ph, —CN, —NO 2 , —CO(C 1-4 alkyl), —CO 2 H, —CO 2 (C 1-4 alkyl), —CONH 2 , —CONH(C 1-4 alkyl), —CON(C 1-4 alkyl) 2 ; and
X is a group selected from the group consisting of: azide, N-maleimide, N-maleimide-furan cycloadduct, thiol, thio acid, sulfonylazide, ethynyl, iodoethynyl and an activated cyclooctynyl group represented by the formulae:
[0000]
[0000] Y is a group selected from the group consisting of: —NHC(═NH)NH 2 , C 6 H 4 —OH
Z is a group selected from the group consisting of: —CO 2 H, Ph
and
when Y is —NHC(═NH)NH 2 , Z is —CO 2 H and when Y is C 6 H 4 —OH, Z is Ph.
[0012] Another aspect of the invention is a process for preparing the compounds as defined above wherein Z is —CO2H and Y is —NHC(═NH)NH2, which comprises:
[0000] a) reacting an azide of formula Q-(R 1 )—N 3 (II) with an alkyne of formula T-C≡C—(R 2 )—NH-PG (protecting group) (III) to obtain a triazole of formula (IV);
b) reacting a triazole of the formula (IV) with a compound of formula S—(R 3 )—CO 2 R a (V) or an alkene of formula H 2 C═CH—CO 2 R a (VI), to provide a compound of formula (VII);
c) replacing the Q group in the compounds of formula (VII) by a group X to obtain a compound of formula VIII; and d) removing the protecting group (PG) in compounds of the formula (VIII) and e) reacting the intermediate amines with H 2 NC(═NH)SO 3 H.
[0000]
[0000] wherein:
R 1 , R 2 , R 3 and X are as defined above; R a is H, methyl, ethyl, tert-butyl or benzyl; T is H or I; Q is HO, methanesulfonyloxy, p-toluenesulfonyloxy, 2-nitrobenzenesulfonyloxy, 4-nitrobenzenesulfonyloxy, trifluoromethanesufonyloxy, Cl, Br or I; PG is H, tert-butoxycarbonyl, allyloxycarbonyl or benzyloxycarbonyl; S in step b) is B(OH) 2 , methanesulfonyloxy, p-toluenesulfonyloxy, 2-nitrobenzenesulfonyloxy, 4-nitrobenzenesulfonyloxy, trifluoromethanesufonyloxy, Cl, Br or I.
[0013] Another aspect of the invention is a process for preparing the compound as defined above wherein, Y is C 6 H 4 —OH and Z is Ph, which comprises:
[0000] a) reacting an azide of formula Q-(R 1 )—N 3 (II) with an alkyne of formula T-C≡C—(R 2 )—(C 6 H 4 OH)—PG (IX) to obtain a triazole of formula (X),
b) reacting a triazole of the formula (X) with a compound of formula S—(R 3 )-Ph (XI), to provide a compound of formula (XII),
c) replacing the Q group in the compounds of formula (XII) by a group X, and
d) removing the protecting group PG.
[0000]
[0000] wherein:
R 1 , R 2 , R 3 and X are as defined above; T is H or I; Q is HO, methanesulfonyloxy, p-toluenesulfonyloxy, 2-nitrobenzenesulfonyloxy, 4-nitrobenzenesulfonyloxy, trifluoromethanesufonyloxy, Cl, Br or I; PG is H, tert-butoxycarbonyl, allyloxycarbonyl or benzyloxycarbonyl; S in step b) is B(OH) 2 ; PG is Si(i-Pr) 3 .
[0014] The appendage group X of the compound is useful to bind to different materials when their surface is functionalized with reactive groups such as azide, sulfonylazide, terminal alkyne, terminal iodoalkyne, cycloalkyne, N-maleimide, N-maleimide-furan cycloadduct, thiol or thio acid. As a result of such reactions, a material-W-peptidomimetic adduct is formed, which contains at least one of such W groups:
[0000]
[0015] Therefore another aspect of the invention relates to a material with the surface chemically modified wherein the X group of the 1,4,5-trisubstituted 1,2,3-triazole according to the 1,4,5-trisubstituted 1,2,3-triazole compound of formula (I) as defined above is replaced by a W the group as defined above.
[0016] The compounds of the invention are mimetics of RGD and/or OGP 10-14 . Among them, (Arg-Gly-Asp) tripeptide and OGP 10-14 (Tyr-Gly-Phe-Gly-Gly) pentapeptide have potential interest for “in vitro” tissue engineering and diagnosis technologies, or to improve the osteogenic properties of implants in human and animal therapy “in vivo”.
[0017] Thus another aspect of the invention relates to a medical device, made from the material described above. It can preferentially be an endosseous implant, or tissue engineering scaffold or cell culture matrices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows the X-ray photoelectron spectroscopy (XPS) spectrum (with three spectra magnifications of C1s, N1s and O1s peaks, FIGS. 2-4 ) for a compact PEEK sample modified at the surface with a mixture of RGD and OGP mimetics, as described in example 18.
[0019] FIG. 2 shows a FIG. 1 spectrum magnification of C1s peak.
[0020] FIG. 3 shows a FIG. 1 spectrum magnification of N1s peak.
[0021] FIG. 4 shows a FIG. 1 spectrum magnification of O1s peak.
DETAILED DESCRIPTION OF THE INVENTION
[0022] As mentioned above, an aspect of the present invention relates to 1,4,5-trisubstituted 1,2,3-triazole compounds of formula (I) as defined above.
[0023] As used herein, the term “alkyl” includes both saturated straight chain and branched hydrocarbon substituents. Preferably, C 1-20 alkyl groups, more preferably C 1-6 alkyl groups. Particularly preferred alkyl groups include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and hexyl.
[0024] As used herein, the term “alkylene” includes biradical hydrocarbon saturated straight chains and branched chains attaching simultaneously two molecular fragments or functional groups. Preferably, C 1-20 alkylene groups, more preferably C 1-6 alkylene groups. Particularly preferred alkylene groups include, for example, methylene, ethylene, propylene and butylene.
[0025] As used herein, the term “aryl” includes substituted or unsubstituted single-ring aromatic groups in which each atom of the ring is carbon. Preferably the ring is a 5- to 7-membered ring, more preferably a 6-membered ring.
[0026] In a preferred embodiment R 1 is selected from the group consisting of —(CH 2 CH 2 O)rCH 2 CH 2 —; where r is an integer between 0 and 8, R 2 is selected from the group consisting of —CH 2 OCH 2 CH 2 — or —CH 2 OCH 2 —, and R 3 is selected from the group consisting of —CH 2 CH 2 — or —CH═CH—.
[0027] Particularly in the compound of formula (I), Y is —NHC(═NH)NH 2 and Z is —CO 2 H. In other particular embodiment, Y is C 6 H 4 —OH and Z is Ph. Preferably Y is p-C 6 H 4 —OH and Z is Ph.
[0028] Other aspect of the invention relates to a material with the surface chemically modified wherein the X group of the 1,4,5-trisubstituted 1,2,3-triazole compound according to the 1,4,5-trisubstituted 1,2,3-triazole of formula (I) as defined above is replaced by a W group as defined above. Preferably the material with the surface chemically modified wherein in the 1,4,5-trisubstituted 1,2,3-triazole compound Y is —NHC(═NH)NH 2 and Z is —CO 2 H. Preferably the surface chemically modified wherein in the 1,4,5-trisubstituted 1,2,3-triazole compound Y is p-C 6 H 4 —OH and Z is Ph.
[0029] In a preferred embodiment the material is metals, metallic alloys, polymers, ceramics or composites. In particular, those materials that comply with the ISO 10993 standards for evaluating the biocompatibility. Examples of materials are; Ti, Ti alloys, polyethylene, polypropylene, PET, polyamide, polyester, polyurethanes, silicones or PAEK. More preferably the material is PAEK.
[0030] Finally the invention refers to a medical device wherein the device is made from the material as defined above.
[0031] As used herein the term “medical device” means any instrument, apparatus, appliance, material or other article, whether used alone or in combination, intended to be used for the purpose of:
diagnosis, prevention, monitoring, treatment or alleviation of
disease,
diagnosis, monitoring, treatment, alleviation of or compensation
for an injury or handicap,
investigation, replacement or modification of the anatomy or of
a physiological process.
[0035] As used herein the term “medical device” includes stents, stent grafts, catheters, guide wires, balloons, filters (e.g., vena cava filters), vascular grafts, intraluminal paving systems, pacemakers, electrodes, leads, defibrillators, joint and bone implants, spinal implants, access ports, intra-aortic balloon pumps, heart valves, sutures, artificial hearts, neurological stimulators, cochlear implants, retinal implants, and other devices that can be used in connection with therapeutic coatings, prosthetic bone implant, endooseous implant, scaffold for bone tissue regeneration. Such medical devices are implanted or otherwise used in body structures, cavities, or lumens such as the vasculature, gastrointestinal tract, abdomen, peritoneum, airways, esophagus, trachea, colon, rectum, biliary tract, urinary tract, prostate, brain, spine, lung, liver, heart, skeletal muscle, kidney, bladder, intestines, stomach, pancreas, ovary, uterus, cartilage, eye, bone, joints, and the like. Preferably medical device is an implant or cell culture matrix. More preferably endooseous implant or tissue engineering scaffold or cell culture matrices.
[0036] In a preferred embodiment the invention refers a medical device wherein the medical device is an endosseous implant, or tissue engineering scaffold or cell culture matrix, suitable for the replacement of human and animal organs.
[0037] Acronyms of reagents, solvents or techniques used are defined as follows:
[0000] Boc: tert-Butoxycarbonylamino group,
Dansyl: 5-(Dimethylamino)naphthalene-1-sulfonyl group,
DIPEA: Diisopropyletylamine,
DMF: N,N-Dimethylformamide,
NBS: N-Bromosuccinimide,
NMR: Nuclear Magnetic Resonance,
[0038] OGP: Osteogenic Growth Peptide. For the purpose of this invention refers to structures of formula (I), wherein Y is p-C 6 H 4 —OH and Z is Ph.
PEEK: Poly-ether ether ketone,
RGD: Arginine-Glycine-Aspartic acid. For the purpose of this invention refers to structures of formula (I), wherein Y is —NHC(═NH)NH 2 and Z is —CO 2 H
THF: Tetrahydrofuran,
TLC: Thin Layer Chromatography.
[0039] The following examples are provided for illustrative means, and are not meant to be limiting of the present invention.
Example 1
Compound (IV): R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; Q=OH; PG=Boc; T=I
4-(4-tert-Butoxycarbonylamino-2-oxa-butyl)-1-(2-hydroxyethyl)-5-iodo-1,2,3-triazole
[0040] To a stirred solution of CuI (218 mg, 1.15 mmol) in dried CH 3 CN, NBS (223 mg, 1.25 mmol), 2-(tert-butoxycarbonylamino)ethyl propargyl ether (208 mg, 1.04 mmol), 2-azidoethanol (100 mg, 1.15 mmol) and DIPEA (200 μl, 1.15 mmol) were added. The mixture was stirred at room temperature for two hours. The solvent was evaporated, the residue was dissolved in CH 2 Cl 2 , washed with 10% aqueous Na 2 S 2 O 3 and the organic phase was dried (MgSO 4 ) and evaporated. The product was purified by column chromatography (silica gel; EtOAc/hexanes 1:1). Yield: 300 mg (70%). 1H NMR (500 MHz, CDCl 3 ) δ 4.63 (s, 2H), 4.54-4.48 (t, J=4.9, 2H), 4.18 (t, J=5.0, 2H), 3.62 (t, J=5.1, 2H), 3.34 (t, J=5.0, 2H), 1.46 (s, 9H).
Example 2
Compound (VII): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R a =CH 3 ; Q=OH; PG=Boc
4-(4-tert-Butoxycarbonylamino-2-oxa-butyl)-1-(2-hydroxyethyl)-5-(2-methoxycarbonyl-ethyl)-1,2,3-triazole
[0041] A suspension of 4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-1-(2-hydroxyethyl)-5-iodo-1,2,3-triazole (500 mg, 1.21 mmol), Pd(OAc) 2 (27.2 mg, 0.121 mmol) and NaHCO 3 (254.7 mg, 3.03 mmol) in anhydrous DMF (5 mL) was prepared in a flame-dried flask under nitrogen atmosphere. Methyl acrylate (273.1 μL, 3.03 mmol) was added and the mixture was stirred at 85° C. overnight. The solvent was evaporated and the product was purified by column chromatography (silica gel, EtOAc/hexanes 1:1). This intermediate product (355 mg, 0.96 mmol) was dissolved in dry MeOH and ammonium formate (302.2 mg, 4.8 mmol) and 10%-Pd—C (107.8 mg, 0.096 mmol) were added. The mixture was refluxed overnight. The product was purified by filtration over celite. Yield: 330 mg (74%). 1 H NMR (500 MHz, CDCl 3 ): δ 4.55 (s, 2H), 4.40 (t, J=4.7, 2H), 4.06 (t, J=4.7, 2H), 3.64 (s, 3H), 3.54 (t, J=5.1, 2H), 3.26 (s, 2H), 3.05 (t, J=7.3, 2H), 2.68 (t, J=7.4, 2H), 1.41 (s, 9H).
Example 3
Compound (VIII): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R a =CH 3 ; X=N3; PG=Boc
1-(2-Azidoethyl)-4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-5-(2-carboxyethyl)-1,2,3-triazole
[0042] To a stirred solution of 4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-1-(2-hydroxyethyl)-5-(2-methoxycarbonylethyl)-1,2,3-triazole (135 mg, 0.36 mmol) prepared in Example 2, cooled to 0° C. in dried CH 2 Cl 2 was added triphenyl phosphine (190.2 mg, 0.73 mmol) and NBS (129.0 mg, 0.73 mmol). The mixture was stirred over one hour. The solvent was evaporated and the crude product was dissolved in dried DMF. Then, NaN 3 (94.3 mg, 1.45 mmol) and NaI (54.3 mg, 0.36 mmol) were added and the mixture was stirred at room temperature over 48 hours. After evaporation of the solvent, the crude product was dissolved in THF/H 2 O (1:1) and LiOH.H 2 O (151.9 mg, 3.62 mmol) was added and the mixture was stirred for 8 hours. Then, the solvent was evaporated and the product was purified by acid and basic extraction with CH 2 Cl 2 . Yield: 143.9 mg (70%). 1 H NMR (500 MHz, CD 3 OD) δ 4.64 (s, 2H), 4.57 (t, J=5.5, 2H), 3.88 (t, J=5.5, 2H), 3.54 (t, J=5.5, 2H), 3.25 (t, J=5.3, 2H), 3.12 (t, J=7.3, 2H), 2.73 (t, J=7.2, 2H), 1.45 (s, 9H).
Example 4
Compound (VIII): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 3 =—CH 2 CH 2 —; R a =CH 3 ; X=N 3 ; PG=Boc
1-(16-Azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-5-(2-methoxycarbonylethyl)-1,2,3-triazole
[0043] In a flame-dried flask, 4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-1-(2-hydroxyethyl)-5-(2-methoxycarbonyl-ethyl)-1,2,3-triazole (0.27 mmol, 100 mg), prepared as described in Example 2, was dissolved in dry THF (2 mL) under nitrogen atmosphere and after addition of DIPEA (0.54 mmol, 96 μL), the mixture was cooled to 0° C. Subsequently, a solution of triphosgene (0.17 mmol, 49 mg) was added dropwise and then the mixture was allowed to reach the room temperature during 30 min. The suspension was filtered through a celite pad and the solvent was evaporated under pressure to obtain the intermediate chloroformate, which was immediately dissolved in dry CH 2 Cl 2 (2 mL). DIPEA (0.54 mmol, 93 μL) and 8-azido-3,6-dioxaoctylamine (0.27 mmol, 60 mg) were added and the mixture was kept stirring overnight. The product was purified by column chromatography using CH 2 Cl 2 /MeOH 90/10 as eluent. Yield: 85 mg (51%). IR (cm −1 ): 3339, 2869, 2102 (N 3 ), 1704 (C═O), 1522 (tri). 1H NMR (500 MHz, CDCl 3 ) δ 4.61 (s, 2H, OCH 2 C═C tri ), 4.56 (t, J=5.1, 2H, N 1tri CH 2 CH 2 ), 4.49 (t, J=5.0, 2H, N 1tri CH 2 CH 2 ), 3.67 (s, 3H, COOCH 3 ), 3.67-3.51 (m, 14H, OCH 2 CH 2 NHBoc and OCH 2 CH 2 O), 3.40-3.28 (m, 6H, OCH 2 CH 2 NHBoc, OCH 2 CH 2 NHCOO and OCH 2 CH 2 N 3 ), 3.04 (t, J=7.6, 2H, CH 2 CH 2 CO 2 CH 3 ), 2.70 (t, J=7.2, 2H, CH 2 CH 2 CO 2 CH 3 ), 1.43 (s, 9H, tBu).
Example 5
Compound (I): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H
1-(2-Azidoethyl)-5-(2-carboxyethyl)-4-(4-N-guanidyl-2-oxa-butyl)-1,2,3-triazole
[0044] A 6M HCl solution in dioxane (2 mL, 12 mmol) was added to 1-(2-azidoethyl)-4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-5-(2-carboxyethyl)-1,2,3-triazole (80 mg, 0.21 mmol) and the mixture was stirred at room temperature over 1 h. Then, the solvent was evaporated, the crude amine hydrochloride was dissolved in methanol (5 mL) and sodium bicarbonate was added until pH=7. Amino(imino)methanesulfonic acid (31.0 mg, 0.25 mmol) was added, the mixture was stirred at room temperature over 1 h. and it was evaporated to dryness. The residue was extracted with MeOH (3×5 mL) and the solution was evaporated at reduced pressure. Yield (90%). 1 H NMR (500 MHz, D 2 O): δ 4.62 (s, 1H), 4.46 (t, J=5.0, 1H), 3.97 (t, J=5.0, 1H), 3.68 (t, J=4.8, 1H), 3.38-3.33 (m, 1H), 3.00 (t, J=7.6, 1H), 2.43 (t, J=7.6, 1H).
Example 6
Compound (I): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 3 =—CH 2 CH 2 —; X=N 3 Y=—NHC(═NH)NH 2 ; Z=CO 2 H
1-(16-Azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-5-(2-carboxyethyl)-4-(4-N-guanidyl-2-oxa-butyl)-1,2,3-triazole
[0045] A 4M HCl solution in dioxane (2 mL, 8 mmol) was added to 1-(16-azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-4-(4-tert-butoxycarbonylamino-2-oxa-butyl)-5-(2-methoxycarbonylethyl)-1,2,3-triazole (75 mg, 0.14 mmol) and the mixture was stirred at room temperature over 2 h. Then, the solvent was evaporated, the crude amine hydrochloride (45 mg, 0.08 mmol) was dissolved in methanol (5 mL) and potassium carbonate was added until slightly basic pH. Amino(imino)methanesulfonic acid (11 mg, 0.09 mmol) was added, the mixture was stirred at room temperature over 1 h. Lithium hydroxide (4.0 mg, 0.09 mmol) was added and the solution was stirred for 4 h. Upon completion, the solids were filtered off with MeOH (3×5 mL), the solution was evaporated at reduced pressure and the resulting crude product was purified by preparative reverse phase HPLC (C18 column, MeCN:H 2 O 80:20). Yield (75%). 1 H NMR (500 MHz, D 2 O) δ 4.63 (m, 4H, OCH 2 C═C tri and N 1tri CH 2 CH 2 ), 4.46 (m, 2H, N 1tri CH 2 CH 2 ), 3.70-3.60 (m, 12H), 3.50 (m, 2H, OCH 2 CH 2 NHCOO), 3.44 (t, J=4.2, 2H, OCH 2 CH 2 N 3 ), 3.36 (t, J=4.7, 2H, OCH 2 CH 2 NHCOO), 3.18 (m, 2H, CH 2 CH 2 guanidine), 3.02 (t, J=7.4, 2H, CH 2 CH 2 CO 2 H), 2.45 (t, J=7.5, 2H, CH 2 CH 2 CO 2 H).
Example 7
Compound (X): R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; Q=OH; T=I; PG=Si( i Pr) 3
1-(2-Hydroxyethyl)-5-iodo-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole
[0046] To a stirred solution of CuI (401 mg, 2.11 mmol) in dried CH 3 CN, NBS (409 mg, 2.30 mmol), 4-triisopropylsilyloxy-benzyl propargyl ether (610 mg, 1.92 mmol), 2-azidoethanol (100 mg, 1.15 mmol) and DIPEA (367 μl, 2.11 mmol) were added. The mixture was stirred at room temperature for two hours. The solvent was evaporated, the residue was dissolved in CH 2 Cl 2 , washed with 10% aqueous Na 2 S 2 O 3 and the organic phase was dried (MgSO 4 ) and evaporated. The product was purified by column chromatography (silica gel; EtOAc/hexanes 1:1). Yield: 315 mg (31%). 1 H NMR (500 MHz, CDCl 3 ) δ 7.26 (d, J=8.0, 2H), 6.88 (d, J=8.1, 2H), 4.61 (s, 2H), 4.54 (s, 2H), 4.49 (t, J=4.2, 2H), 4.17 (d, J=3.3, 2H), 1.33-1.23 (m, 3H), 1.12 (ds, 18H).
Example 8
Compound (XII): R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; Q=OH; PG=Si( i Pr) 3
1-(2-Hydroxyethyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole
[0047] A suspension of 1-(2-hydroxyethyl)-5-iodo-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole (270 mg, 0.52 mmol) prepared in Example 7, E-2-phenylvinylboronic acid (119.8 mg, 0.79 mmol), bis(triphenylphosphine) palladium (II) dichloride (14.7 mg, 0.02 mmol) and potassium hydroxide (58.8 mg, 1.05 mmol) were dissolved in anhydrous THF (4 mL) and kept at 75° C. during 2 h. The product was purified by column chromatography (silica gel, EtOAc/hexanes 1:1). Yield: 330 mg (92%). 1 H NMR (500 MHz, CDCl 3 ) δ 7.49 (d, J=7.2, 2H), 7.41 (t, J=7.3, 2H), 7.39-7.34 (m, 1H), 7.31 (d, J=13.2, 1H), 7.26 (d, J=8.4, 2H), 6.98 (d, J=16.3, 1H), 6.86 (d, J=8.4, 2H), 4.72 (s, 2H), 4.58 (s, 2H), 4.51-4.46 (m, 2H), 4.18 (dd, J=10.2, 5.4, 2H), 1.32-1.22 (m, 3H), 1.11 (d, J=7.4, 18H).
Example 9
Compound (XII): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; Q=N 3 ; PG=Si( i Pr) 3
1-(16-Azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole
[0048] In a flame-dried flask, 1-(2-hydroxyethyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole (0.20 mmol, 100 mg) prepared as shown in Example 7, was dissolved in dry THF (1.5 mL) under nitrogen atmosphere and after addition of DIPEA (0.39 mmol, 69 μL), the mixture was cooled to 0° C. Subsequently, a solution of triphosgene (0.12 mmol, 36 mg) was added dropwise and then the mixture was allowed to reach the room temperature during 30 minutes. The suspension was filtered through a celite pad and the solvent was evaporated under pressure to obtain the intermediate chloroformate [ 1 H NMR (500 MHz, CDCl 3 ) δ 7.50 (d, J=7.3, 2H), 7.45-7.35 (m, 4H), 7.26 (d, J=8.0, 2H), 6.92 (d, J=16.4, 1H), 6.86 (d, J=7.9, 2H), 4.80-4.70 (m, 6H), 4.59 (s, 2H), 1.31-1.21 (m, 3H), 1.11 (d, J=7.3, 18H)]. The product was dissolved in dry CH 2 Cl 2 (1.5 mL) and sequentially DIPEA (0.39 mmol, 69 μL) and tetraethylene glycol (0.20 mmol, 43 mg) were added and the mixture was kept stirring overnight. The product was purified by column chromatography using CH 2 Cl 2 /MeOH 90/10 as eluent. Yield: 116 mg (78%). IR (cm −1 ): 2944, 2866, 2102 (N 3 ), 1720 (C═O), 1509. 1 H NMR (500 MHz, CDCl 3 ) δ 7.47 (d, J=7.7, 2H), 7.42-7.21 (m, 6H), 6.92 (d, J=16.3, 1H), 6.85 (d, J=8.0, 2H), 4.72 (s, 2H), 4.64 (t, J=4.8, 2H), 4.57 (s, 2H), 4.48 (s, 2H), 3.69-3.49 (m, 11H), 3.45-3.41 (m, 2H), 3.39-3.32 (m, 2H), 3.28 (t, J=10.9, 2H), 1.30-1.19 (m, 3H), 1.09 (d, J=7.4, 18H).
Example 10
Compound (I): R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph
1-(2-Azidoethyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole
[0049] In a dried flask cyanuric chloride (55.93 mg, 0.30 mmol) and DMF (61.06 μL) were warmed at 25° C. for 10 min. After the formation of a white solid, CH 2 Cl 2 (0.5 mL) was added, followed by 1-(2-hydroxyethyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole (70 mg, 0.14 mmol). The mixture was kept at room temperature during one hour and the solvent was evaporated. The resulting crude product was dissolved again in acetone, sodium azide (89.71 mg, 1.38 mmol) was added and the mixture was stirred for 24 hours. Then, cesium fluoride (300 mg, 2.0 mmol) was added, and the resulting crude was evaporated and purified by column chromatography (silica gel, EtOAc/hexanes 1:1). 1 H NMR (500 MHz, CDCl 3 ) δ 7.50 (d, J=7.2, 2H), 7.47-7.33 (m, 4H), 7.33-7.25 (m, 3H), 6.95 (d, J=16.3, 1H), 6.87 (d, J=8.2, 2H), 4.75 (s, 2H), 4.71 (t, J=6.4, 2H), 4.60 (s, 2H), 4.01 (t, J=6.4, 2H).
Example 11
Compound (I): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph
1-(16-Azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-hydroxyphenyl)-propyl]-1,2,3-triazole
[0050] A suspension of 1-(16-azido-5-aza-3,8,11,14-tetraoxa-4-oxohexadecyl)-5-[(E)-(2-phenyl)vinyl]-4-[2-oxa-3-(4-triisopropylsilyloxyphenyl)-propyl]-1,2,3-triazole (0.14 mmol, 105 mg) prepared in Example 9, and cesium fluoride (0.70 mmol, 106 mg) in methanol (1.5 mL) was stirred at room temperature for one hour. Then the solvent was evaporated and the product was purified by column chromatography using CH 2 Cl 2 /MeOH 95:5 as eluent. Yield: 50 mg (60%). IR(cm −1 ): 3328, 2867, 2101 (N 3 ), 1705 (C═O), 1517. 1 H NMR (500 MHz, CDCl 3 ) δ 7.47 (d, J=7.4, 2H), 7.44-7.25 (m, 5H), 7.20 (dd, J=17.2, 8.0, 2H), 6.86 (d, J=16.6, 1H), 6.80 (d, J=8.1, 2H), 4.75 (s, 2H), 4.64 (d, J=4.8, 2H), 4.57 (s, 2H), 4.47 (s, 2H), 3.58 (ddd, J=35.4, 14.6, 6.2, 10H), 3.39-3.35 (m, 2H), 3.35-3.27 (m, 2H), 3.21 (d, J=4.8, 2H).
Example 12
Poly(Etheretherketone) PEEK with the Surface Modified as Cycloalkyne. Material According to Formula [PEEK]=N—O—(R 4 )—X, Wherein: R 1 =—CH 2 CH 2 OCH 2 CH 2 O—; X=cyclooctyn-3-yl
[0051] Compact PEEK consisted of mechanically polished PEEK-1000 semicrystalline 20×20×5 mm size square samples from Ketron (KETRON PEEK 1000, ref. 41300000, PoliFluor S.L) and medical grade implantable PEEK CLASSIX LSG compact disk samples from Invibio (PoliFluor S.L).
[0052] Porous PEEK consisted of disk samples (9 mm diameter/3 mm thin), prepared according to patent EP10382243.3 (Porous PEEK article as an implant) with VESTAKEEP® 2000 P.
[0053] Compact PEEK and porous PEEK materials with the surface modified as oxime [PEEK]=N—OH were prepared following a procedure described in Macromolecules, 1991, 24: 3045-3049.
[0054] PEEK oxime: Both compact and porous PEEK samples were cleaned by immersion in an ultrasonic bath with methanol for 30 min and subsequently dried at room temperature under reduced pressure overnight. Each set of 10 samples of porous and compact PEEK, 3.0 g of hydroxylamine hydrochloride, 10 mL of ethanol, and 2 mL water were introduced to a round-bottomed flask. Sodium hydroxide (5.5 g) was added in five portions, shaking after each addition. The balloon flask was purged with nitrogen, then heated at 40° C. for 24 h, and finally refluxed for 24 h. After cooling the suspension, the samples were extracted, rinsed successively with 10% aqueous HCl (5×30 mL) and ethanol (3×30 mL), and dried at room temperature.
[0055] 3-(6-Iodo-1,3-dioxahexyl)-cyclooctyne: To a solution of O-(cyclooctyn-3-yl)-diethylene glycol (100 mg, 0.47 mmol) in anhydrous DMF (10 mL) was added (PhO) 3 PMeI (0.43 g, 0.94 mmol). The resulting solution was stirred at r.t. for 30 min. Then, MeOH (1 mL) was added the mixture was evaporated at reduced pressure. The crude obtained was used without additional purification. Yield: 103.2 mg, (65%). 1 H-NMR (500 MHz, CDCl 3 ): δ 4.24 (t, 1H, —CH—C≡C—), 3.77-3.67 (m, 5H, O—CH 2 ), 3.53 (m, 1H, —CH—O), 1.91 (t, 2H, CH 2 —I), 2.25-1.45 (m, 10H, —CH 2 —).
[0056] Compact and porous PEEK oxime samples (n=2), prepared as above, were introduced under nitrogen atmosphere into a test tube containing a mixture of potassium carbonate (0.41 g), 3-(6-Iodo-1,3-dioxahexyl)-cyclooctyne (0.20 g) and acetone (2 mL). The suspension was stirred at 40° C. for 24 h., and the samples were washed repeatedly with water and methanol. Finally, the samples were dried at r.t. under vacuum for 5 h.
[0057] Surface characterization data for compact PEEK modified as cycloalkyne. XPS analysis: C 83.3%, O 14.8%, N 1.9%.
[0058] Surface characterization data for porous PEEK modified as cycloalkyne. Contact angle: 139.2°±18.0. XPS analysis: C 81.8%, O 17.2%, N 1.0%.
[0000]
Example 13
Porous PEEK with the Surface Modified as RGD Mimetic. Material (XIII): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 4 =—CH 2 CH 2 OCH 2 CH 2 O—; W=4,5-bicyclooctene-1,2,3-triazole
[0059] Porous PEEK oxime samples (n=2) functionalized as cycloalkyne as described in Example 12, were introduced under nitrogen atmosphere into a test tube containing a 2 mL of a THF/H 2 O 1:1 mixture. Then, 0.2 mg of compound of formula (I): (R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H), prepared in Example 5, were added and the suspension was stirred at 40° C. for 24 h. The sample was washed repeatedly with a solution of HCl 0.1M, an aqueous solution of NH 3 (pH=11), water and methanol and dried at room temperature under vacuum for 5 h.
[0060] Surface XPS analysis for porous PEEK modified with RGD mimetic: C 79.4%, O 18.7%, N 1.9%).
Example 14
Compact PEEK with the Surface Modified as RGD Mimetic. Material (XIII): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 4 =—CH 2 CH 2 OCH 2 CH 2 O—; W=4,5-bicyclooctene-1,2,3-triazole
[0061] Compact PEEK-M oxime samples (n=2) functionalized as cycloalkyne as described in Example 12, was reacted with 0.2 mg of RGD mimetic of formula (I): (R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H). Reaction conditions and purification were identical to the Example 13.
[0062] Surface characterization data for polished compact PEEK modified with RGD mimetic. XPS analysis: C 84.4%, O 13.3%, N 2.3%.
Example 15
Compact PEEK-M with the Surface Modified as RGD Mimetic. Material (XIII): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 4 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; W=4,5-bicyclooctene-1,2,3-triazole
[0063] Compact PEEK oxime samples (n=2) functionalized as cycloalkyne as described in Example 12, was reacted with 0.2 mg of RGD mimetic of formula (I): (R=—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 3 =—CH 2 CH 2 —; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H prepared as described in Example 6). Reaction conditions and purification were identical to the Example 13.
[0064] Surface characterization data for polished compact PEEK modified with RGD mimetic. XPS analysis: C 82.2%, O 14.6%, N 3.2%.
[0000]
Example 16
Compact PEEK with the Surface Modified as OGP Mimetic. Material (XIV): R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; R 4 =—CH 2 CH 2 OCH 2 CH 2 O—; W=4,5-bicyclooctene-1,2,3-triazole
[0065] Compact PEEK oxime samples (n=2) functionalized as cycloalkyne as described in Example 12, was reacted with 0.2 mg of OGP mimetic of formula (I): (R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph prepared as described in Example 10). Reaction conditions and purification was identical to the Example 12.
[0066] Surface characterization data for polished compact PEEK modified with OGP mimetic. XPS analysis: C 75.6%, O 21.2%, N 3.2%.
Example 17
Compact PEEK-M with the Surface Modified with OGP Mimetic. Material (XIV): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; R 4 =—CH 2 CH 2 OCH 2 CH 2 O—; W=4,5-bicyclooctene-1,2,3-triazole
[0067] A compact PEEK oxime discs functionalized as cycloalkyne as described in Example 12, was introduced under nitrogen atmosphere into a test tube containing 1 mL of THF/H 2 O 1:1 mixture, 0.1 mg of OGP mimetic (I) (R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph) prepared as described in Example 11. The suspension was stirred at 40° C. for 24 h. The discs were washed repeatedly with THF, water and methanol and dried at room temperature under vacuum for 5 h.
[0068] Surface XPS analysis for the compact PEEK modified with OGP mimetic: C 79.8%, O 17.7%, N 2.5%.
[0000]
Example 18
Compact PEEK with the Surface Modified with a Combination of RGD and OGP peptidomimetics. Material (XV): R 1 =R 3 =—CH 2 CH 2 —; R 2 =—CH 2 CH 2 OCH 2 —; R 4 =—OCH 2 CH 2 OCH 2 CH 2 —; R 5 =—CH═CH—; R 6 =—CH 2 OCH 2 —; W=4,5-bicyclooctene-1,2,3-triazole
[0069] Compact PEEK oxime discs (n=2) functionalized as cycloalkyne as described in Example 12, were introduced under nitrogen atmosphere into a test tube containing 2 mL of THF/H 2 O 1:1 mixture, 0.1 mg of RGD mimetic of formula (I) (R 1 =R 3 =—CH 2 CH 2 —; R 2 —CH 2 OCH 2 CH 2 ; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H) prepared as described in Example 5, and 0.1 mg of OGP mimetic of formula (I) (R 1 =—CH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph) prepared as described in Example 10. The suspension was stirred at 40° C. for 24 h. The discs were washed repeatedly with a solution of HCl 0.1M, an aqueous solution of NH 3 (pH=11), water and methanol and dried at room temperature under vacuum for 5 h.
[0070] Surface XPS analysis for compact PEEK (XV) modified with RGD and OGP: C 74.9%, O 21.6%, N 3.59% ( FIG. 1 ).
Example 19
Compact PEEK with the Surface Modified with a Combination of RGD and OGP Peptidomimetics. Material (XV): R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 3 =—CH═CH—; R 4 =—OCH 2 CH 2 OCH 2 CH 2 —; R 5 =—CH═CH—; R 6 =—CH 2 OCH 2 —; W=4,5-bicyclooctene-1,2,3-triazole
[0071] Compact PEEK oxime discs (n=2) functionalized as cycloalkyne prepared as described in Example 12, were introduced under nitrogen atmosphere into a test tube containing 2 mL of THF/H 2 O 1:1 mixture, 0.1 mg of RGD mimetic of formula (I) (R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 CH 2 —; R 3 =—CH 2 CH 2 —; X=N 3 ; Y=—NHC(═NH)NH 2 ; Z=CO 2 H) prepared as described in Example 10, and 0.1 mg of OGP mimetic (I) (R 1 =—[CH 2 CH 2 O] 3 CH 2 CH 2 HN(CO)OCH 2 CH 2 —; R 2 =—CH 2 OCH 2 —; R 3 =—CH═CH—; X=N 3 ; Y=p-C 6 H 4 OH; Z=Ph) prepared as described in Example 11. The suspension was stirred at 40° C. for 24 h. The discs were washed repeatedly with a solution of HCl 0.1M, an aqueous solution of NH 3 (pH=11), water and methanol and dried at room temperature under vacuum for 5 h. | The present invention relates to compounds, containing a central 1,4,5-trisubstituted 1,2,3-triazole core and a reactive appendage appropriate to form covalent “click” bonds on the surface of materials functionalized with reactive groups including: azide, terminal alkyne, cyclooctalkyne, thiol, maleimide or thiolacid groups. These compound are nonpeptide mimetics of RGD (Arg-Gly-Asp) and/or, OGP 10-14 (Tyr-Gly-Phe-Gly-Gly), osteogenic peptides. Also, the present invention relates to a process for the preparation of the compounds containing a 1,4,5-trisubstituted 1,2,3-triazole core. These compounds are particularly useful for medical devices, in particular implants and tissue engineering and cell culture matrices. | 0 |
FIELD OF THE INVENTION
[0001] The invention relates to a structural member for construction of buildings such as houses. The invention has particular but not exclusive application in use as a chord for forming a roof truss for a building.
PRIOR ART
[0002] A metal roof truss is commonly constructed with box-section chords and C-section web members. The box-section chords are formed by two C-sections individually roll formed and then further fabricated by dimple formation for locating and/or fastening by welding, riveting, hole punched and bolted or screwed to close the two C-sections. The fabrication of the section is a specialized operation and adds additional cost and time to the manufacture of a chord.
[0003] Open sections are generally quicker and cheaper to manufacture than box-sections comprising two C-sections, but they lack the strength and stiffness required for chords. Thus, whenever open sections, such as channel and Z-sections are used in the fabrication of building frames and roof trusses, additional precautions such as providing oversized sections or additional structural support must be taken to compensate for their inherent strength deficiencies. This of course increases the cost of many structures formed therefrom.
[0004] In addition, effecting the joints between top and bottom chords and between web members and chords mostly requires specialized joining members or shaping for welding which adds to the cost and complexity of such structures.
SUMMARY OF THE INVENTION
[0005] A truss or other structural member formed from the combination of an open structural member and a chord having a c-shaped, closed or elliptical cross section and/or a second open structural member.
[0006] In one aspect the invention broadly resides in an elongated open structural member having a cross-section including a minor flange, a major flange and a web interconnecting the flanges and having a section axis at right angles to the longitudinal axis of the structural member and passing through the flanges and wherein:
[0007] the web includes a linear portion substantially coincident with the section axis and a divergent portion which extends to one side of the section axis;
[0008] the minor flange extends to the one side of the section axis;
[0009] the major flange extends from the divergent portion to the opposite side of the section axis, and
[0010] the section configuration being such that an inverted and reversed corresponding open structural member is nestable within the open structural member with their respective linear section portions alongside one another and with each minor flange located in an abutting relationship against the underside of the adjacent major flange.
[0011] The linear portion may be any suitable length but preferably the linear portion is extends along a major portion of the section axis between the flanges. The term “suitable” is qualified by the particular use of the open structural member and where a corresponding member is used the length of the linear portion suitably enables overlap of the linear section portions or portions thereof.
[0012] The divergent portion may have any suitable shape. The divergent portion may be curved, straight, or comprise a series of straight segments. In a preferred embodiment the divergent portion is a single straight portion and the major flange extends at an acute angle from the divergent portion.
[0013] The linear portion connects to the minor flange at its end opposite the divergent portion. Preferably the minor flange extends from the linear portion at an angle of substantially 90 degrees. Alternatively, the linear portion may include a second divergent portion which extends to the minor flange. The second divergent portion may be curved, straight, or comprise a series of straight segments.
[0014] The minor flange is preferably shorter than the major flange and most preferably is shorter than the section of the major flange which extends between the section axis and the end of the major flange remote from the divergent portion, and hereinafter referred to as its “free edge”. Preferably the intersection with the section axis occurs about midway across the-major flange.
[0015] Preferably the flanges are substantially flat or at least parts which are substantially diagonally opposite with respect to the section axis are substantially flat. Preferably the flanges or at least the flat parts are substantially parallel.
[0016] Preferably the open structural member includes a limitor to restrict lateral movement with respect to the section axis of connected members along the section axis. Preferably the limitor is a return flange extending along the free edge of the major flange.
[0017] The major and/or the minor flanges preferably both terminate in a return flange. The return flange preferably returns substantially parallel to the section axis. Preferably the return flange of the major flange is spaced further from the section axis than the free edge of the minor flange so that a reversed and inverted corresponding open structural member may nest within the structural member.
[0018] The open structural member is preferably asymmetrical in shape and allows the nesting of an inverted and reversed corresponding open structural member with the minor flange of one open structural member locatable within the major flange of the other open structural member and overlapping of the linear section portions.
[0019] The invention in a further aspect broadly resides in an elongated open structural member having a minor flange, a major flange and a web interconnecting the flanges and having a planar web portion extending at right angles to the minor and major flanges, and wherein:
[0020] the web includes a divergent portion which extends to one side of the planar portion;
[0021] the minor flange extends to the one side of the planar portion;
[0022] the major flange extends from the divergent portion to the opposite side of the planar portion;
[0023] the minor flange and the major flange each have a return along their respective free edge, and wherein
[0024] the configuration being such that an inverted and reversed corresponding open structural member is locatable with its planar portion alongside the planar portion of the structural member and each minor flange including its return being locatable within the confine defined by the adjacent return flange of the major flange.
[0025] In another aspect the invention resides in a chord member for a truss, each chord member of the truss being an open structural member as described above whereby the chord member may be disposed with its major flange outermost and with interconnections between intersecting chord members being made by extending the web and minor flange of one intersecting chord member across the web and minor flange of the other chord member with the webs overlying one another enabling through fastening together. In such arrangement the webs overlap at joints for connection to one another such as by bolting or screwing or welding and, if desired disposed with their minor flanges nested within the major flanges of the opposing chord member.
[0026] It is also preferred that the chords of the truss are interconnected by truss members which may be open section members suitably terminated for web to web connection to the webs of the top and bottom chord members.
[0027] The assembled truss with the open structural member forming the top and bottom chord members with C-section truss members preferably has the chord members proud of the truss members thereby allowing stacking of the assembled truss and transportation of the stacks without risk of damage to the truss members by the overlying chord members. In contrast conventional box section chords have C-section truss members joined at their flat surfaces thereby causing the truss members to be proud of the chord members and exposing the truss members to damage during stacking and their transportation.
[0028] In a further aspect the invention broadly resides in a composite beam formed by the nesting of two open structural members as described variously above in an inverted and reversed orientation with respect to each other with the minor flange of one member located within the major flange of the other member and overlapping of the planar portions and fastening means connecting the open structural members together.
[0029] The open structural members may be prevented from lateral displacement with respect to one another by the fastening means but preferably they include returns along the free edges of the major flanges which restrain lateral displacement of the open structural members with respect to one another.
[0030] Preferably the nesting of the open structural members as described above forms two closed sections thereby providing strength to the beam.
[0031] A further aspect of the invention includes a truss including a first support member having a substantially planar portion; at least one second support member having a non-planar cross section and an end with a second substantially planar section; and a connector securing the first substantially planar section to the second substantially planar portion. The second support member may have a C-shaped or elliptical cross section. Also, the second substantially planar portion is a crimped version of the non-planar cross section. The connector may be a bolt or other suitable connector well known in the art. The end of the second support member may have third and fourth substantially planar portions arranged at angle to the second substantially planar portion. Further, this embodiment is not limited to one second support member and may contain a plurality of second support members connected to the first support member by the connector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Several typical embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:
[0033] [0033]FIG. 1 is an end elevation of an elongate open structural member;
[0034] [0034]FIG. 2, 3, 4 are perspective views of the member;
[0035] [0035]FIG. 5 is an end elevation of two members nested in reverse and inverted orientation with respect to each other;
[0036] [0036]FIG. 6 a is a front elevation of an assembled truss with open structural members as top and bottom chord members;
[0037] [0037]FIG. 6 b - g shows various connections on the truss shown in FIG. 6 a;
[0038] [0038]FIG. 7 a - c are views of the interconnection of two open structural members;
[0039] [0039]FIG. 8 a - c are views of different attachments of a C-section truss members to a chord;
[0040] [0040]FIG. 9 a - c show alternative connections between chords and truss members;
[0041] [0041]FIG. 10 a - c shows an alternative structural member; and
[0042] [0042]FIG. 11 a - b shows interconnections of closed section chord members and open structural members.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] With reference to FIGS. 1, 2, 3 and 4 there is shown an elongate open structural member 10 having a minor flange 12 and a major flange 13 separated by a web 14 . A longitudinal axis 11 b of the member 10 is shown in FIG. 2. The web 14 includes a planar portion 17 and a divergent portion 18 . A section axis 11 a is coincident with the linear portion 17 . The minor flange 12 extends from the planar portion 17 at 90 degrees. The minor flange 12 includes a return flange 15 . The return flange 15 is parallel to the section axis 11 a. The divergent portion 18 diverges from the section axis 11 a at an acute included angle indicated by alpha. The divergent portion 18 is connected to the major flange 13 . The major flange 13 includes a broad planar flange portion 19 which is connected to the divergent portion 18 forming an acute included angle. The major flange 13 also includes a return flange 20 parallel to the section axis.
[0044] As shown in FIG. 5, two elongate open structural members 30 , 31 as described above are able to be nested with one member being in reverse and inverted orientation with respect to the other. To effect nesting minor flanges 32 a and 32 b, are located within major flanges 33 b and 33 a respectively in abutting relationship. In this position the respective web portions 34 a , 34 b partly overlie each other thereby allowing fasteners to join both members 30 , 31 to prevent lateral movement. The abutting relationship of the respective flanges 32 a , 32 b , 33 a , 33 b prevents movement along the section axis. The nesting of the two elongate members forms two closed sections 35 , 36 which provide strength and stiffening to the composite member.
[0045] Roof trusses 40 as shown in FIGS. 6 a - g are constructed with elongate open structural members forming top and bottom chords 41 , 42 and C-section truss members 43 . The connection of the top chord 41 to the bottom chord 42 is shown in FIG. 6 b. The major flanges 44 , 45 of the top and bottom chords 41 and 42 respectively are outermost. The minor flange 46 of the top chord 41 is partially located and confined in major flange 45 . The rearward flat side 47 of top chord 41 partly overlaps frontward flat side 48 of the bottom chord 42 . There is shown an intermediate connection plate 49 between sides 47 and 48 . The connection plate 49 is attached to the bottom chord 42 by bolts 50 , 51 and to the top chord 41 by bolts 50 , 52 . An alternative connection is shown in FIG. 9 c where top chord 60 is bolted to bottom chord 61 at 62 .
[0046] Connections of the C-section truss members 43 to the chord members 41 , 42 are shown in FIGS. 6 c , 6 d , 6 f . In FIG. 6 d the truss members 43 are crimped and joined to the-top chord 41 by bolt 70 . In FIG. 6 e the truss members 43 are attached to the bottom chord 42 by bolt 72 . The underlying truss members 43 are at least crimped to accommodate the connection. The connection shown in FIG. 6 c has the truss member 43 connected by bolt 71 to the bottom chord 42 . The chords 41 , 42 are proud of the truss members 43 in the truss 40 . A preferred connection includes the planar surface of the crimped end of the truss member secured to the planar portion 17 of the web 14 .
[0047] The apex 80 of the truss 40 is shown in FIGS. 6 f and 6 g. An apex plate 81 serves to connect top chords 41 by bolts 82 . The apex plate 81 has recessed ribs 83 to provide additional stiffening. The apex plate 81 also has a recess 84 for the location of a C-section truss member 43 . The C-section truss member 43 is connected to the apex plate 81 by bolt 85 . Alternative connections in an apex are shown in FIG. 9 a and 9 b. In FIG. 9 a top chords 63 and C-section truss members- 64 are connected by bolt 65 . Similarly in FIG. 9 b the top chords 66 and C-section truss member 67 are connected by bolt 68 .
[0048] In FIG. 7 a - c there is shown chords 90 , 91 with major flanges 92 , 93 outermost and minor flange 94 of chord 91 located partially within the major flange 92 of chord 90 .
[0049] In FIGS. 8 a - c there is shown attachment of crimped C-section truss members 95 to elongate open structural member chords 96 by bolts 97 . The C-section truss member 95 has end 98 crimped presenting a flat surface 99 for connecting to the chord 96 . The flat surface 99 is attached to the side of the web portion 100 opposite the narrow flange 101 .
[0050] [0050]FIGS. 10 a - c depict different embodiments of open structural member 10 .
[0051] [0051]FIGS. 11 a - b show another embodiment of a structure 110 , such as a roof truss or other structures well known in the art. The structure 110 includes an open structural member 10 connected to two truss members 112 with a single bolt 114 .
[0052] Truss members 112 have a closed or substantially elliptical cross-section formed by sidewall 112 a and an area of void space within the sidewall 112 a.
[0053] As shown in FIG. 11 a, the elliptical truss members 112 have an end 116 which is crimped such that the sidewall 112 a of the elliptical truss member 112 is compressed to decrease the space therebetween.
[0054] [0054]FIG. 11 b , which is a top view of FIG. 11 a also shows the crimped nature of the ends of elliptical truss members 112 .
[0055] Also as shown in FIGS. 11 a - b, the crimped end 116 has two side portions 118 and 120 , which in a preferred embodiment form an angle β with a center portion 122 . The angle β at which the side portions 118 and 120 bend with respect to the center portion facilitates securing multiple truss members with a single bolt 114 .
[0056] The center portion 122 is relatively planar and is secured to the planar portion of another structural member by a single bolt. Center portion 122 has sidewall 112 a which in a preferred embodiment are closer together than the sidewalls 112 a in the side portions 118 and 120 . The angle β at which the side portions 118 and 120 may bend with respect to the center portion facilitates securing multiple truss members with a single bolt 114 .
[0057] Another feature of the connection of the truss members 112 to the open structural member 10 includes the substantially planar portion 17 of open structural member 10 abutting the substantially planar surface of truss member 112 .
[0058] Although FIGS. 11 a - b include two structural members 112 , the number of structural members which may be attached is not limited to two and may be one or several. Further, the invention is also not limited to the use of a bolt and other suitable connectors well known in the art may be used. Also, although the structural members are shown connected to open structural member 10 which has a minor flange, major flange and divergent portion, connection to this type of structural member is not necessary. Rather, structural members 112 may be connected to any structural member known in the art having a substantially planar surface.
[0059] The embodiment described above provides a number of advantages including efficient roll forming for chord production; provision of a strengthened and stiffer open section member chord with proper orientation of the major flange outermost; the ability to treat or coat the entire chord or composite beam or truss having open sections prior to use; compact truss stacking with chords being proud of truss web members thereby minimizing damage to the truss members during transportation and reducing transport and storage costs; the ability of the chords to overlap for interconnection while maintaining the overlapped chords in line one above the other for symmetry of the truss and to be easily fastened together at terminations.
[0060] It will of course be realized that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. | A truss including a first support member, at least one second support member and a connector connecting the support members. The first support member has a first substantially planar portion. The second support member has a non-planar cross section substantially along a length thereof and an end with a second substantially planar portion. The connector secures the first and second substantially planar portions. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to clones for the Hinc II restriction endonuclease and modification methylase, and to the production of these enzymes from the clones.
Restriction endonucleases are a class of enzymes that occur naturally in bacteria. When they are purified away from other contaminating bacterial components, restriction endonucleases can be used in the laboratory to break DNA molecules into precise fragments. This property enables DNA molecules to be uniquely identified and to be fractionated into their constituent genes. Restriction endonucleases have proved to be indispensable tools in modern genetic research. They are the biochemical `scissors` by means of which genetic engineering and analysis is performed.
Restriction endonucleases act by recognizing and binding to particular sequences of nucleotides (the `recognition sequence`) along the DNA molecule. Once bound, they cleave the molecule within, or to one side of, the sequence. Different restriction endonucleases have affinity for different recognition sequences. Over one hundred different restriction endonucleases have been identified among many hundreds of bacterial species that have been examined to date.
Bacteria usually possess only a small number restriction endonucleases per species. The endonucleases are named according to the bacteria from which they are derived. Thus, the species Haemophilus aegyptius, for example synthesizes 3 different restriction endonucleases, named HaeI, HaeII and HaeIII. These enzymes recognize and cleave the sequences (AT)GGCC(AT), PuGCGCPy and GGCC respectively. Escherichia coli RY13, on the other hand, synthesizes only one enzyme, EcoRI, which recognizes the sequence GAATTC.
While not wishing to be bound by theory, it is thought that in nature, restriction endonucleases play a protective role in the welfare of the bacterial cell. They enable bacteria to resist infection by foreign DNA molecules like viruses and plasmids that would otherwise destroy or parasitize them. They impart resistance by binding to infecting DNA molecules and cleaving them each time that the recognition sequence occurs. The disintegration that results inactivates many of the infecting genes and renders the DNA susceptible to further degradation by exonucleases.
A second component of bacterial protective systems are the modification methylases. These enzymes are complementary to restriction endonucleases and they provide the means by which bacteria are able to protect their own DNA and distinguish it from foreign, infecting DNA. Modification methylases recognize and bind to the same nucleotide recognition sequence as the corresponding restriction endonuclease, but instead of breaking the DNA, they chemically modify one or other of the nucleotides within the sequence by the addition of a methyl group. Following methylation, the recognition sequence is no longer bound or cleaved by the restriction endonuclease. The DNA of a bacterial cell is always fully modified, by virtue of the activity of its modification methylase and it is therefore completely insensitive to the presence of the endogenous restriction endonuclease. It is only unmodified, and therefore identifiably foreign, DNA that is sensitive to restriction endonuclease recognition and attack.
With the advent of genetic engineering technology, it is now possible to clone genes and to produce the proteins and enzymes that they encode in greater quantities than are obtainable by conventional purification techniques. The key to isolating clones of restriction endonuclease genes is to develop a simple and reliable method to identify such clones within complex `libraries`, i.e. populations of clones derived by `shotgun` procedures, when they occur at frequencies as low as 10 -3 to 10 -4 . Preferably, the method should be selective, such that the unwanted, majority, of clones are destroyed while the desirable, rare, clones survive.
Type II restriction-modification systems are being cloned with increasing frequency. The first cloned systems used bacteriophage infection as a means of identifying or selecting restriction endonuclease clones (HhaII Mann et al., Gene 3: 97-112, (1978); EcoRII: Kosykh et al., Molec. gen. Genet 178: 717-719, (1980); PstI: Walder et al., Proc. Nat. Acad. Sci. USA 78 1503-1507, (1981)). Since the presence of restriction-modification systems in bacteria enables them to resist infection by bacteriophages, cells that carry cloned restriction-modification genes can, in principle, be selectively isolated as survivors from libraries that have been exposed to phage. This method has been found, however, to have only limited value. Specifically, it has been found that cloned restriction-modification genes do not always manifest sufficient phage resistance to confer selective survival.
Another cloning approach involves transferring systems initially characterized as plasmid-borne into E.coli cloning plasmids (EcoRV: Bougueleret et al., Nucleic Acids Res. 12:3659-3676, (1984); PaeR7: Gingeras and Brooks, Proc. Natl. Acad. Sci. USA 80:402-406, (1983); Theriault and Roy, Gene 19:355-359, (1982); PvuII: Blumenthal et al., J. Bacteriol. 164:501-509, (1985)).
A third approach, and one that is being used to clone a growing number of systems, involves selecting for an active methylase gene see, e.g. EPO Publication No. 193, 413, published September 3, 1986 and (BsuRI: Kiss et al., Nucleic Acids Res. 13:6403-6421, (1985)). Since restriction and modification genes tend to be closely linked, clones containing both genes can often be isolated by selecting for just the one gene. Selection for methylation activity does not always yield a complete restriction-modification system however, but instead sometimes yields only the methylase gene (BspRI: Szomolanyi et al., Gene 10:219-225, (1980); BcnI: Janulaitis et al, Gene 20: 197-204 (1982); BsuRI: Kiss and Baldauf, Gene 21: 111-119, (1983); and MspI: Walder et al., J. Biol. Chem. 258:1235-1241, (1983)).
A potential obstacle to cloning restriction-modification genes lies in trying to introduce the endonuclease gene into a host not already protected by modification. If the methylase gene and endonuclease gene are introduced together as a single clone, the methylase must protectively modify the host DNA before the endonuclease has the opportunity to cleave it. On occasion, therefore, it might only be possible to clone the genes sequentially, methylase first then endonuclease. Another obstacle to cloning restriction-modification systems lies in the discovery that some strains of E. coli react adversely to cytosine or adenine modification; they possess systems that destroy DNA containing methylated cytosine (Raleigh and Wilson, Proc. Natl. Acad. Sci., USA 83:9070-9074, (1986)) or methylated adenine (Heitman and Model, J. Bact., 196:3243-3250, (1987); Raleigh, Trimarchi, and Revel, Genetics, (in press)). Cytosine-specific or adenine-specific methylase genes cannot be cloned easily into these strains, either on their own, or together with their corresponding endonuclease genes. To avoid this problem it is necessary to use mutant strains of E.coli (McrA - and McrB - or Mrr - ) in which these systems are defective.
Because purified restriction endonucleases, and to a lesser extent, modification methylases, are useful tools for characterizing and rearranging DNA in the laboratory, there is a commercial incentive to obtain strains of bacteria through recombinant DNA techniques that synthesize these enzymes in abundance. Such strains would be useful because they would simplify the task of purification as well as providing the means for production in commercially useful amounts.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a clone containing the genes for the Hinc II restriction endonuclease and modification methylase derived from Haemophilus influenzae Rc (NEB strain #126, a sample of which was deposited in the ATCC under designation number 53876) , as well as related methods for the production of the enzymes. More specifically, this invention relates to clones which express the restriction endonuclease Hinc II, an enzyme which recognizes the DNA sequence GTPy PuAC and cleaves as indicated between the first 5' Py and Pu by the arrow. See Landy, Ruesdisueli, Robinson, and Ross, Biochemistry, 13:2134-2142, (1974); Kelly and Smith, J. Mol. Biol., 51:393-409, (1970); Roy and Smith, J. Mol. Biol., 81 427-444, (1973); Roy and Smith, J. Mol. Biol., 81:445-459, (1973); Smith and Wilcox, J. Mol. Biol., 51:379-391, (1970) , the disclosure of which is hereby incorporated by reference herein.
The preferred method for cloning this enzyme comprises forming a library containing the DNA from Haemophilus influenzae Rc, isolating those clones which contain DNA coding for the Hinc II modification methylase and screening among these to identify those that also contain the Hinc II restriction endonuclease gene.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the scheme for cloning the Hinc II restriction endonuclease.
FIG. 2 illustrates the scheme for producing the Hinc II restriction endonuclease.
FIG. 3 is a restriction map of the 3.0 Kb Hind III fragment from Haemophilus influenzae Rc that encodes the Hinc II restriction endonuclease and modification methylase. The fragment was cloned into the Hind III site of pBIIHI.2 (ATCC 67902) to create p(pBIIHI.2)HincIIRM-8.0-AI and subsequently subcloned into pUC19 (ATCC 37254) to create p(pUC19)HincIIRM-5.7-4 and p(pUC19)HincIIRM-5.7-10
FIG. 4 is a photograph of an agarose gel demonstrating Hinc II restriction endonuclease activity in cell extracts of E.coli RR1 (ATCC 31343) carrying p(pUC19)HincIIRM-5.7-4 and p(pUC19)HincIIRM-5.7-10 (NEB #520).
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a method for cloning Hinc II restriction and modification genes and producing the restriction endonuclease Hinc II from clones produced thereby. This approach takes advantage of the fact that clones have been selected on the basis of containing expressed Hinc II restriction and methylase genes by the use of an endonuclease selection. Such clones are resistant to digestion in vitro by Hinc II restriction endonuclease.
The present invention also relates to a method for cloning the Hind II modification and restriction genes and producing the Hind II restriction endonuclease from clones produced thereby.
The methods described herein by which the Hinc II restriction gene and methylase gene are preferably cloned and expressed include the following steps:
1. The genomic DNA of Haemophilus influenzae Rc or Haemophilus influenzae Rd strains are purified.
2 The genomic DNA is digested fully with a restriction endonuclease such as Bgl II restriction endonuclease.
3. The resulting Bgl II fragments are ligated into the Bgl II cloning site of a cloning vector, such as pBIIOI (ATCC 67901) or the BamH I site of pUC19 (ATCC 37254) or pBR322 (ATCC 37017) or pACYC177 (ATCC 37031) and the mixture is used to transform an appropriate host cell such as E. coli RR1 cells which are mrr - .
4. The transformed mixture is plated onto media selective for transformed cells, such as the antibiotics ampicillin, tetracycline, or chloramphenicol. After incubation, the transformed colonies are collected together into a single culture, the cell library.
5. The recombinant plasmids are purified in toto from the cell library to make the plasmid library.
6. The plasmid library is digested to completion with the Hinc II restriction endonuclease, prepared from Haemophilus influenzae Rc by a method similar to that described in Watson et aI, supra. Hinc II digestion differentially destroys unmodified, non-methylase-containing, clones, increasing the relative frequency of Hinc II methylase clones.
7 The selected DNA is transformed back into an appropriate host such as E.coli RR1, and transformants are recovered by plating onto selective media. The colonies are picked and their DNA is analyzed for the presence of the Hinc II modification gene: the plasmids that they carry are purified and incubated with the Hinc II restriction endonuclease to determine whether they are resistant to digestion. Total cellular DNA (chromosomal and plasmid) is also purified and incubated with the Hinc II restriction endonuclease. The DNA of clones that carry the Hinc II modification gene should be fully modified, and both plasmid DNA and total DNA should be substantially resistant to digestion.
8. The Hinc II restriction endonuclease is produced from Haemophilus influenzae Rc cells carrying the Hinc II restriction and modification genes. The cells are propagated in a fermenter in a rich medium containing ampicillin.
9. The cells are harvested by centrifugation.
10 The cells are disrupted by sonication to produce crude cell extract containing the Hinc II restriction endonuclease activity.
11. The crude cell extract containing the Hinc II restriction endonuclease activity is purified by standard ion-exchange and affinity chromatography techniques.
12. The endonuclease so purified will be homogeneous on SDS polyacrylmide gel electrophoresis and to have a molecular weight of 27,000 daltons and a specific activity of approximately 250,000 units/mg of protein titered on lambda DNA.
13 The amino terminal sequence of the endonuclease is obtained, and a DNA oligo probe is made based on the protein sequence.
14. The location of the endonuclease is mapped to the methylase as well as to the Haemophilus influenzae Rc and Haemophilus influenzae Rd genomes.
15. Haemophilus influenzae Rc genomic DNA is digested fully with a restriction endonuclease such as Hind III restriction endonuclease. Haemophilus influenzae Rd genomic DNA could be digested fully with a restriction endonuclease such as Cla I or EcoR I which generates fragments known to contain the Hind II modification and restriction genes.
16. The resulting Hind III fragments are ligated into the Hind III cloning site of a cloning vector, such as pBIIHI.2 (ATCC 67902) or the Hind III site of pUC19, pBR322 or pACYC177 and the mixture is used to transform an appropriate host cell such as E. coli RR1 cells.
17. The transformed mixture is plated onto media selective for transformed cells, such as the antibiotics ampicillin, streptomycin, or chloramphenicol. After incubation, the transformed colonies are collected together into a single culture, the cell library.
18. The recombinant plasmids are purified in toto from the cell library to make the plasmid library.
19. The plasmid library is digested to completion with the Hinc II restriction endonuclease, prepared from Haemophilus influenzae Rc by a method similar to that described in Watson et al, supra. Hinc II digestion differentially destroys unmodified, non-methylase-containing, clones, increasing the relative frequency of Hinc II methylase clones.
20. The selected DNA is transformed back into an appropriate host such as E.coli RR1, and transformants are recovered by plating onto selective media. The colonies are picked and their DNA is analyzed for the presence of the Hinc II modification gene: the plasmids that they carry are purified and incubated with the Hinc II restriction endonuclease to determine whether they are resistant to digestion. Total cellular DNA (chromosomal and plasmid) is also purified and incubated with the Hinc II restriction endonuclease. The DNA of clones that carry the Hinc II modification gene should be fully modified, and both plasmid DNA and total DNA should be substantially resistant to digestion.
21. Clones carrying the Hinc II restriction endonuclease are identified by preparing crude extracts of the clones which were determined to carry the Hinc II methylase gene, and assaying the crude extract for Hinc II restriction endonuclease activity. The level of Hinc II activity in the crude cell extract is determined to be approximately 1,000 units per gram of cells of the clone p(pBIIHI.2)HincIIRM-8.0-Al.
22. The Hind III fragment containing the methylase and endonuclease genes was subcloned into Hind III cleaved and dephosphorylated pUC19.
23. The clone containing the recombinant plasmids p(pUC19)HincIIRM-5.7-4 and p(pUC19)HincIIRM-5.7-10 which is positive for the Hinc II restriction endonuclease activity contains a single 3.0 Kb Hind III DNA fragment inserted into the Hind III cloning site of pUC19.
24. A number of restriction endonuclease sites for various restriction endonucleases were mapped on this plasmid and are shown in FIG. 3. The positions of the genes have been determined by deletion subcloning and mapping via Southern hybridizations using DNA oligomers as probes.
25. The Hinc II restriction endonuclease is produced from cells carrying the Hinc II restriction and modification genes on the plasmid p(pUC19)HincIIRM-5.7-10. The cells are propagated in a fermenter in a rich medium containing ampicillin.
26. The cells are harvested by centrifugation.
27 The cells are disrupted by sonication to produce crude cell extract containing the Hinc II restriction endonuclease activity.
28. The crude cell extract containing the Hinc II restriction endonuclease activity is purified by standard ion-exchange and affinity chromatography techniques.
29. The endonuclease so purified is found to be homogeneous on SDS polyacrylmide gel electrophoresis and to have a molecular weight of 27,000 daltons and a specific activity of approximately 250,000 units/mg of protein titered on lambda DNA.
Although the above-outlined steps represent the preferred mode for practicing the present invention, it will be apparent to those skilled in the art that the above-described approach can vary in accordance with techniques known in the art.
The following example is given to illustrate embodiments of the present invention as it is presently preferred to practice. It will be understood that this example is illustrative, and that the invention is not to be considered as restricted thereto except as indicated in the appended claims.
EXAMPLE
Cloning of Hinc II Restriction Endonuclease Gene
1. Genomic DNA purification: Approximately five grams of Haemophilus influenzae Rc cells were thawed and resuspended in 0.1M Tris-HCl, pH 7.1, 0.1M ETDA (25 ml) in a Corning plastic tube (50 ml). A solution of 60 mg of lysozyme in 35 ml of the above buffer was divided into two 50 ml plastic tubes and equal portions (15 ml) of the cell suspension added to each. The solutions were incubated at 37° C. for fifteen minutes. SDS was added from a 20% stock solution to adjust the final conc. of SDS to 1%. 200 ul of a Proteinase K (20 mg/ml stock) was added and incubated for one hour at 37° C. The solution appered stringy and diffuse at this point but was not clear. Added 2 ml of 10% SDS/8% sarcosyl to the tubes (1 ml each) and heated at 55° C. for two hours. The sample remained stringy but not totally cleared. The samples were dialyzed against TE (10 mM Tris-HCl, pH 7.1, 1 mM EDTA) (2 1) with a single change - total 16 hours. After the dialysis the solution (98 ml) was prepared for CsCl gradients by dilution with an equal vol. of TE pH 8.0, divided into two portions and to each an addition of 98.0 g of CsCl and 1 ml of a 5 mg/ml Ethidium bromide was made. The twenty tubes were spun in the Ti70 rotor for 48 hrs at 44,000 rpm. The bands were removed and extracted with water saturated isobutanol. The solution was dialyzed against the same buffer (4 1) as before and then phenol and chloroform extracted (one time each). This solution was dialyzed once again to remove phenol and then subjected to electrophoresis.
2. Limit digestion: The purified DNA was cut with
Bgl II to achieve total digestion as follows: 300 ul of DNA at 100 ug/ml in 10mM Tris pH 7.5, 10 mM MgCl 2 , 100 mM NaCl, 10 mM mercaptoethanol buffer was dispensed into three tubes. To the tube was added 50 units of Bgl II. The tubes were incubated at 37° C. for one hour, then phenol/chloroform extracted and ethanol precipitated. The pellets were redissolved in 300 ul of 10 mM Tris-HCl, 1 mM EDTA, pH 8.0 and 10 ul from each analyzed by agarose gel electrophoresis.
3. Ligation: The fragmented DNA was ligated to pBIIOI (pBR322 with a Bgl II linker inserted into the EcoR I site) as follows: 10.0 ug of Bgl II digested Haemophilus influenzae Rc DNA (100 ul) was mixed with 2.0 ug of Bgl II-cleaved and dephosphorylated pBlIOI (20.0 ul) and ethanol precipitated. The DNA was centrifuged at 12,000 g, 4° C. for 15 minutes and washed once with 100 ul 70% ethanol. The DNA was resuspended in 99 ul of 1X ligation buffer (50 mM Tris, pH 7.5, 10 mM MgCl 2 10 mM DTT, 0.5 mM ATP), 1 ul of T4 DNA ligase was added and the mixture allowed to incubate at 16° C. for 16 hours. Aliquiots of 2.5 and 5.0 ul were used to transform E. coli strain RR1 as follows: Each aliquot was mixed with 200 ul of ice-cold competent E. coli RR1 cells and placed on ice for thirty minutes. After a 2-minute heat shock at 42° C., the cells were diluted with one ml of Luria-broth (L-broth) and grown for one hour at 37° C.
4. Primary Cell Library: The transformed cell cultures were centrifuged, resuspended in 250 ul volumes and plated onto Luria-agar (L-agar) plates containing 100 ug/ml ampicillin. After overnight incubation at 37° C., the plates were removed and the approximately 5000 colonies scraped-up into 25 ml of LB with antibiotic. Plasmid DNA was prepared from these cells as follows: the cells were pelleted by centrifugation and three grams of cell paste was resuspended in 14 ml of 25 mM Tris-HCl , 10 mM EDTA pH 8.0 and 50 mM glucose. The suspension was made 4.0 mg/ml in lysozyme and incubated at 25 degrees for 5 minutes. A 27 ml aliquot of 1% sodium dodecyl sulfate and 0.2 N NaOH was added followed by mixing of the solution and incubated for 5 minutes at 0 degrees. Genomic DNA was precipitated by the addition of 20 ml of ice-cold 3M potassium acetate, pH 4.8, vortexed gently for 10 seconds, left on ice for 5 minutes and centrifuged at 12,000 xg for ten minutes. The supernatant was removed and extracted with an equal volume of phenol/chloroform (1:1). The layers were separated by centrifugation at 10,000 xg for 5 minutes. The upper layer was removed and extracted with an equal volume of chloroform. The layers were separated by centrifugation at 10,000 g for 5 minutes. The upper layer was removed and the nucleic acids precipitated by the addition of two volumes of ethanol. The precipitate was collected by centrifugation at 12,000 xg for twenty minutes. The pellet was washed with 70% ethanol once and repelleted as before. The pellet was dried under vacuum and resuspended in 8 ml of 10 mM Tris-HCl, 1 mM EDTA, pH 8.0. The DNA solution was prepared for cesium chloride-ethidium bromide equilibrium density centrifugation by the addition of 8.9 grams of cesium chloride and 0.9 ml of a solution of ethidium bromide (5 mg/ml) were added. The DNA solution was centrifuged at 44,000 rpm for 48 hours and the resulting plasmid band of DNA was removed with a syringe and 18 g needle. The ethidium bromide was removed by extracting with an equal volume of CsCl-water-saturated isopropanol. The cesium chloride was removed by dialysis. The DNA was extracted with an equal volume of phenol/chloroform (1:1), and ethanol precipitated. The resultant DNA pellet was resuspended in 1.0 ml 10 mM Tris-HCl, 1 mM EDTA, pH8.0.
5. Primary Selection and Selected Library: 2 ug (30.0 ul) of the plasmid library was diluted into 60 ul of restriction endonuclease digestion buffer (10 mM Tris pH 7.5, 10 mM MgCl 2 , 10 mM mercaptoethanol, 100 mM NaCl and 100 ug of bovine serum albumin). 100 units (3 ul) of Hinc II restriction endonuclease were added and the tube was incubated at 37° C. for 2 hr, at which time 7U (1 ul) of calf intenstinal phosphatase was added and the reaction was incubated for an additional 30 minutes. Aliquots of this reaction mixture, 2 ul and 4 ul, were mixed with 200 ul of ice-cold competent E. coli RR1 cells and transformed, plated and grown overnight as for the primary library.
6. Analysis of individuals: Colonies from the above transformation were picked and plated on LB agar plates containing ampicillin and tetracycline. Eighteen colonies, which were amp R and tet R were grown up in 10 ml cultures and the plasmids that they carried were prepared by the following miniprep purification procedure, adapted from the method of Birnboim and Doly (Nucleic Acids Res. 7: 1513 (1979)).
Miniprep Procedure: Each culture was processed as follows: The 1.5 ml overnight culture was pelleted at 6,000 xg for 5 minutes. The supernatant was poured off and the cell pellet was resuspended in 150 ul of 25 mM Tris, 10 mM EDTA, 50 mM glucose, pH 8.0, containing 1 mg/ml lysozyme. After five minutes at room temperature, 200 ul of 0.2M NaOH, 1% SDS was added and the tube was shaken to lyse the cells, then placed on ice. After five minutes, 150 ul of 3M sodium acetate, pH 4.8, was added and shaken and placed on ice for an additional five minutes. The precipitate that formed was spun down at 12,000 xg, 4° C. for 10 minutes. The supernantant was removed and extracted with an equal volume of phenol/chloroform (1:1). The layers were separated by centrifugation at 10,000 xg for five minutes. The supernatant was poured into a centrifuge tube containing 880 ul of ethanol and mixed. After 10 minutes at room temperature, the tube was spun at 12,000 xg for 10 minutes to pellet the precipitated nucleic acids. The supernatant was discarded and the pellet was washed again with one ml of 70% ethanol-water, repelleted and dried at room temperature for 30 minutes under vacuum. Once dry, the pellet was resuspended in 50 ul of 10 mM Tris, 1 mM EDTA, pH 8 0 containing 20 ug/ml RNase and incubated for 1 hour at 37° C. to digest the RNA.
The plasmid minipreps were subsequently analyzed by digestion with Hinc II and Bgl II.
7. Methylase Gene Clones: 10% of the plasmids that were analyzed were found to be resistant to Hinc II and to carry a Bgl II fragment of approximately 6.2 Kb in length. These plasmids were subsequently shown to carry only the Hinc II modification methylase gene and not the restriction endonuclease gene. The other 90% of the plasmids looked at were not resistant to Hinc II and contained spurious fragments or were vector religated.
8. Restriction Gene Clones: The clones identified above (section 7) as carrying the Hinc II modification methylase gene were also tested for the Hinc II restriction endonuclease gene. This was performed as follows: The remaining portion of the overnight culture was used to check for endonuclease activity. This was done as follows:
Endonuclease Assays:
10× restriction endonuclease-buffer: 100 mM Tris,
pH 7.5, 100 mM MgCl 2 , 100 mM 2-mercaptoethanol, 1M NaCl.
Cell extracts were prepared as follows: Cells from one ml were pelleted by centrifugation at 4,000 rpm for five minutes. The supernatant was discarded and the pellet was resuspended in one ml of sonication buffer (10 mM Tris, pH 7.5, 100 mM NaCl, 5 mM DTT, 0.1 mM EDTA) and sonicated gently for two 10-second bursts to disrupt the cells. The tube was spun for ten minutes in a microfuge at 4° C., and the supernatant was used as the cell extract. The extract, 1 ul and 5 ul, were incubated with one ug of lambda DNA in 50 ul of 1× restriction endonuclease buffer for fifteen minutes at 37° C. Neither of the clones tested had endonuclease activity.
9. Hinc II endonuclease from Haemophilus influenzae Rc designated NEB#126 was propagated in a fermenter at 37 degrees C. in TRY-YE Broth medium consisting of: tryptone, 10.0 g per liter; yeast extract, 5.0 g per liter; NaCl, 2.0 g per liter; K 2 HPO 4 , 4.4 g per liter; glucose, 2.0 g per liter; hemin bovine, 10 mg per liter; NAD;DPN, 2.0 mg per liter. The cells are collected by centrifugation and the cell paste is used fresh or stored at -70° C.
10. All subsequent steps are carried out at 4° C.
11. The cell paste (200 grams) is thawed and the cells are resuspended in 400 mls sonication buffer (20 mM K 2 PO 4 , pH7.3, 0.1 mM EDTA, 10 mM B-mercaptoethanol, .0.1M NaCl).
12. The cells are disrupted by sonication (250 watts for two minutes, cooled on ice for five minutes, three times), to achieve release of approximately 50 mg of soluble protein per ml of suspended cells.
13. The insoluble cell debris is removed by centrifugation at 21,000× g for 20 minutes.
14. The supernatant fluid is applied to a phosphocellulose column (5×35 cm) (Whatman P-11) equilibrated with 20 mM KH 2 PO 4 , pH 6.9, 100 mM NaCl, and 10 mM 2-mercaptoethanol. The column is washed with two column volumes of the above buffer. The flow-though from the column is collected in a single flask. Hinc II endonuclease is retained by the column and elutes between 0 3 and 0.6M NaCl. The most active fractions are pooled and dialyzed against 20mM K 2 PO 4 , pH7.3, 0.1 mM EDTA, 10 mM B-mercaptoethanol, 0.1M KCl.
15. The pool from the phosphocellulose column is applied to a Heparin-Sepharose CL-6B column (2.5×25 cm) equilibrated with 20 mM K 2 PO 4 , pH 7.4, 0.1 mM EDTA, 10 mM B-mercaptoethanol, 0.1M KCl and washed with two column volumes of the same buffer. A linear gradient of KCl from 0.1M to 1.0M (total volume 700 ml) is developed and applied to the column. Ten ml fractions are collected. The fractions are assayed for the presence of the Hinc II restriction endonuclease activity on lambda DNA. The active fractions are pooled and dialysed against 100 volumes of buffer (20 mM K 2 PO 4 , pH7.3 0.1 mM EDTA, 10 mM B-mercaptoethanol, 0.1M KCl.
16. The dialyzed pool (50 ml) of Hinc II activity is applied to a 1 ml Mono Q FPLC column (Pharmacia) and washed with buffer S (20 mM K 2 PO 4 , pH6.9 10 mM B-mercaptoethanol, 0.05M KCl and a 40 ml linear gradient from 50 mM KCl to 01.0 M KCl is developed in S buffer and applied to the column. One ml fractions are collected and assayed for the presence of Hinc II restriction endonuclease activity.
17. The center fractions containing the majority of Hinc II activity are applied to a 1 ml Poly Cat-A FPLC column (Pharmacia) and washed with buffer S (20 mM K 2 PO 4 , pH6.9 10 mM B-mercaptoethanol, 0.05M KCl and a 40 ml linear gradient from 50 mM KCl to 01 0 M KCl is developed in S buffer and applied to the column. One ml fractions are collected and assayed for the presence of Hinc II restriction endonuclease activity. The two most active fractions are homogeneous. The endonuclease was found to have a specific activity of approximately 250,000 units/mg protein and a molecular weight on SDS-polyacrylamide gels of 27,000 Daltons.
18. 10 ug of the homogeneous Hinc II endonuclease was subjected to amino terminal protein sequencing on an Applied Biosystems Model 470A gas phase protein sequencer. The first 24 residues were degraded. The sequence obtained was the following: X F I K P I X Q D I N X X L I G Q K V K X X K X (refer to Table 1 for explanation of 1 letter code for protein sequence).
19. Based on the protein sequence, a 14-mer oligomer was made with the following sequence: 5' ATH GGN CAR AAA GT 3' (H =A, C, or T; N=A, C, G, or T; R=A or G) which was used to map the location of the amino terminal end of the endonuclease on p(pBIIOI)HincM-10.5-1. This oligomer was also used to obtain DNA sequence which verified the protein sequence and was used to have a sequence specific 25-mer oligomer made with the following sequence: 5' ATG AGT TTC ATA AAA CCT ATT TAT C 3'. Using this 25-mer oligomer, DNA sequence was obtained that helped to determine the direction of the endonuclease and further defined the location of the amino terminal end of the endonuclease as well as the portion of the endonuclease gene that was present in p(pBIIOI)HincM-10 5-1. The DNA sequence obtained was the following: 5' TAC TCA AAG TAT TTT GGA TAA ATA GTC CTA TAA TTG NNA ATA TTA ATC GGG CAA AAA GTG AAA CGT CCT AAA TCA GGT ACT CTG TCA GGT CAT GCT GCA GGG GAA CCA TTT GAA AAA TTA GTA TAT AAG TTT TTG AAA GAA AAC CTG TCA GAT TTA ACA TTT AAG CAA TAT GAA TAT CTT AAT GAT TTA TTT ATG AAG AAC CCT GCG ATA ATT GAG CAT G 3'. The 25-mer oligomer was also used to map the endonuclease gene to various restriction fragments of the Haemophilus inflenzae Rc genome. With the use of a sequence specific oligomer made to the vector DNA, and a deletion clone known to be located within the methylase gene, the direction of the methylase gene was determined in the same manner that the direction of the endonuclease gene was determined.
20. Based on the data obtained in step 18, purified Haemophilus influenzae Rc genomic DNA (prepared as in step 1) was subjected to a limit digestion using Hind III as follows: 300 ul of DNA at 100 ug/ml in 10 mM Tris pH 7.5, 10 mM MgCl 2 , 100 mM NaCl, 10 mM mercaptoethanol buffer was dispensed into one tube. To the tube was added 50 units of Hind III. The tubes were incubated at 37° C. for one hour, then phenol/chloroform extracted and ethanol precipitated. The pellets were redissolved in 300 ul of 10 mM Tris-HCl, 1 mM EDTA, pH 8.0 and 10 ul from each analyzed by agarose gel electrophoresis.
21. Ligation: The fragmented DNA was ligated to pBIIHI.2 (pN01523, with a Hpa I linker inserted into the Pvu II site and a Bgl II linker inserted into the EcoR I site) as follows: 10.0 ug of Hind III digested Haemophilus influenzae Rc DNA (100 ul) was mixed with 2.0 ug of Hind III-cleaved and dephosphorylated pBIIHI.2 (20.0 ul) and ethanol precipitated. The DNA was centrifuged at 12,000 g, 4° C. for 15 minutes and washed once with 100 ul 70% ethanol. The DNA was resuspended in 99 ul of 1× ligation buffer (50 mM Tris, pH 7.5, 10 mM MgCl 2 10 mM DTT, 0.5 mM ATP), 1 ul of T4 DNA ligase was added and the mixture allowed to incubate at 16° C. for 16 hours. Aliquots of 2.5 and 5.0 ul were used to transform E. coli strain RR1 as follows: Each aliquot was mixed with 200 ul of ice-cold competent E. coli RR1 cells and placed on ice for thirty minutes. After a 2-minute heat shock at 42° C., the cells were diluted with one ml of Luria-broth (L-broth) and grown for one hour at 37° C.
22. Primary Cell Library: Prepared as in step 4 with one additional step: based on the data obtained from step 18, the libraries were probed with the sequence specific 25-mer oligomer (step 19), looking for a Hind III fragment of the appropriate size which was presumed to contain the endonuclease and methylase This fragment was present in the primary cell library.
23. Primary Selection and Selected Library: Prepared as in step 5.
24. Analysis of individuals: Colonies from the above transformation were picked and plated on LB agar plates containing ampicillin and LB agar plates containing ampicillin and streptomycin. Eighteen colonies, which were amp R and strep S were grown up in 10 ml cultures and the plasmids that they carried were prepared by the miniprep purification procedure described in step 6. The plasmid minipreps were subsequently analyzed by digestion with Hinc II and Hind III.
25. Methylase Gene Clones: 27% of the plasmids that were analyzed were found to be resistant to Hinc II and to carry a Hind III fragment of approximately 3.0 Kb in length. These plasmids were subsequently shown to carry both the Hinc II modification methylase and restriction endonuclease genes. These plasmids were also found to each carry one or more spurious fragments. The other 73% of the plasmids looked at were not resistant to Hinc II and either contained spurious fragments or were vector religated.
26. Restriction Gene Clones: The clones identified above (section 24) as carrying the Hinc II modification methylase gene were also tested for the Hinc II restriction endonuclease gene. This was performed as described in step 8. All of the clones tested had endonuclease activity.
27. All methylase positive clones were found to contain endonuclease. These clones were found to synthesize about 1,000 units of Hinc II restriction endonuclease per gram of wet cell paste in either orientation.
28 p(pBIIHI.2)HincIIRM-8.0-AI was used to transform an isogenic series of E. coli strains, looking for potential effects caused by either the Mcr A, Mcr B or mrr phenotypes. It was discovered that this RM clone was unable to transform, and hence be propagated, in any mrr + strains.
29. The 3.0 kb Hind III fragment from p(pBIIHI.2)HincIIRM-8.0-Al was gel prepped and used in a ligation reaction with Hind III cut and dephosphorylated pUC 19 in the following manner: 250 ng of the 2.7 kb gel prepped fragment (20 ul) was mixed with 100 ng (1 ul) of Hind III cut and dephosphorylated pUC 19 and ethanol precipitated. The DNA was centrifuged at 12,000 g, 4° C. for 15 minutes and washed once with 100ul 70% ethanol. The DNA was resuspended in 10 ul of 1X ligation buffer (50 mM Tris, pH 7.5, 10 mM MgCl 2 10 mM DTT, 0.5 mM ATP), 1 ul of T4 DNA ligase was added and the mixture allowed to incubate at 16° C. for 16 hours. An liquots of 5.0 ul was used to transform E. coli strain RR1 as follows: Each aliquot was mixed with 200 ul of ice-cold competent E. coli RR1 cells and placed on ice for thirty minutes. After a 2-minute heat shock at 42° C., the cells were diluted with one ml of Luria-broth (L-broth) and grown for one hour at 37° C. The transformed cell cultures were centrifuged, resuspended in 250 ul volumes and plated onto Luria-agar (L-agar) plates containing 100 ug/ml ampicillin. After overnight incubation at 37° C., colonies were picked and plated onto LB agar containing ampicillin and incubated overnight at 37° C. Eighteen colonies, which were amp R were grown up in 10 ml cultures and the plasmids that they carried were prepared by the miniprep purification procedure described in step 6. The plasmid minipreps were subsequently analyzed by digestion with Hinc II and Hind III.
30. Methylase Gene Clones: Over 50% of the plasmids that were analyzed were found to be resistant to Hinc II digestion and to carry a Hind III fragment of approximately 3.0 Kb in length. These plasmids were subsequently shown to carry both the Hinc II modification methylase and restriction endonuclease genes. The remainder of the plasmids were pUC19 religated.
31. Restriction Gene Clones: The clones identified above (section 28) as carrying the Hinc II modification methylase gene were also tested for the Hinc II restriction endonuclease gene. This was performed as described in step 8. All of the clones tested had endonuclease activity.
32. All methylase positive clones were found to contain endonuclease. These clones were found to synthesize about 80,000 units of Hinc II restriction endonuclease per gram of wet cell paste in orientation A, p(pUC19)HincIIRM-5.7-10 (NEB #520), and 2,000 units of Hinc II restriction endonuclease per gram of wet cell paste in orientation B, p(pUC19)HincIIRM-5.7-4.
33. The recombinant plasmid p(pUC)HincIIRM-10-5.7 (NEB #520) which carries the genes encoding the Hinc II restriction endonuclease and methylase was transferred to E coli strain RR1 by transformation, a sample of which has been deposited at the American Type Culture Collection under ATCC Accession No. 40896. In transforming the same isogenic series of strains as in step 27, p(pUC)HincIIRM-10-5.7 (NEB #520) was able to tranform into these strains, but was unable to be propagated in liquid cultures larger then 10 ml.
34. Hinc II endonuclease was prepared as described in steps 9-16 with one alteration, the cells were grown in LB broth medium consisting of: 10 grams per liter, casein hydrolysate; 5 grams per liter, yeast extract; 10 grams per liter, NaCl; 1 gram per liter, magnesium chloride-hexahydrate; 1 gram per liter, glucose; 100 mg per liter ampicillin. The pH is adjusted to 7.2 with NaOH. The endonuclease purified was found to have a specific activity of approximately 250,000 units/mg protein.
TABLE 1__________________________________________________________________________Amino Acid Sequence to mRNA (DNA) Sequence__________________________________________________________________________1 letter code G A V L I S T D N E Q K P H3 letter code Gly Ala Val Leu Ile Ser Thr Asp Asn Glu Gln Lys Pro HismRNA 5' GGA GCA GUA CUA AUA UCA ACA GAC AAC GAA CAA AAA CCA CAC C C C C C C C U U G G G C U G G G G U G G G U U U U U U U or or UUA AGC G U__________________________________________________________________________ 1 letter code R F Y W C M 3 letter code Arg Phe Tyr Trp Cys Met mRNA 5' CGA UUC UAC UGG UGC AUG 3' C U U C G U or AGA G__________________________________________________________________________Special Signals RNA Amino Acid Special Symbols B = D or N UAA = Ochre Z = E or Q UAG = Amber UGA = terminateAmbiguous nucleotide abbreviationsThese abbreviations conform to the proposed IUPAC-IUB standardabbreviations.A C G U/TU/T = U Uracil/ThymineG = G GuanineK = G UC = C CytosineY = C U PyrimidineS = C GB = C G UA = A AdenineW = A UR = A G PurineD = A G UM = A CH = A C UV = A C GN/X = A C G U | The present invention is directed to a method for cloning and producing the Hinc II restriction endonuclease by (1) introducing the restriction endonuclease gene from Haemophilus influenzae Rc into a host whereby the restriction gene is expressed; (2) fermenting the host which contains the vector encoding and expressing the Hinc II restriction endonuclease, and (3) purifying the Hinc II restriction endonuclease from the fermented host which contains the vector encoding and expressing the Hinc II restriction endonuclease activity. | 2 |
This application is a cont. of Ser. No. 08/714,528 filed Sep. 16, 1996, now abandoned. This a cont. application Ser. No. 08/428,689 filed Apr. 25, 1995, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to therapeutic beds and, more particularly, to therapeutic beds of the type having an air cushion support together with an integral fluidized bead surface.
2. Background
The care of patients requiring extensive recuperative periods presents many extraordinary challenges which have not been adequately addressed in the past. Not the least of these challenges is providing a patient support surface that is both sturdy and easy to use, while simultaneously providing preventive therapy and intervention for the numerous complications associated with extended confinement to bed. Burn victims, for instance, typically require extremely low patient interface pressures, high air flow, as well as low shear forces. It is well-known in the art that two of the most ideal patient support surfaces for the immobile patient are low-air-loss beds and fluidized bead beds. Low-air-loss bed and mattress examples are described in U.S. Pat. Nos. 5,005,240 (KINAIR) and 5,022,110 (FIRSTSTEP). Examples of bead beds are described in U.S. Pat. Nos. 4,564,965 (CLINITRON), 5,008,965 (FLUIDAIR), and 5,036,559 (ELEXIS).
Conventional bead beds typically include a bathtub-like tank filled with medical-grade silicone microspheres (or “beads”). Each individual bead typically has a soda-lime core encased within a silicone sphere approximately 100 microns in diameter. A diffuser board is positioned horizontally at the base of the tank, separating two compartments within the tank—an upper compartment which contains the beads and a smaller, lower compartment which serves as a plenum chamber filled with air for fluidizing the beads. With appropriate blowers and temperature control systems, air is blown into the plenum chamber, from which the pressurized air is forced upwardly through the diffuser board and further (often in bubble-like manner) through the beads, giving the beads a liquid-like quality. A filter sheet is draped over the top of the tank to contain the beads while allowing the upward passage of air. The patient can lie either directly on the filter sheet or on a second cover sheet. Despite the liquefied state of the beads, the patient remains buoyant because of the relative density of the beads.
Although such bead beds may actually provide the most therapeutic surface from the standpoint of pressure and microclimate at the patient interface (i.e., interface between patient and mattress), conventional bead beds have many drawbacks. Traditionally, bead bed manufacturers have thought that a significant depth of beads was required in order to provide an adequate patient support with good fluidization. Fluidizing the resulting volume of beads inherently required heavy-duty blowers and related equipment, not to mention the extra structural requirements for the frames of such beds. Conventional bead beds are extremely heavy (approximately 2,000 pounds), which not only makes them difficult to maneuver, but also requires that they be used only in buildings having extremely sturdy support. Second-story placement in wood-frame houses is typically avoided without assessment by a structural engineer. The poor maneuverability and excessive weight may also present risks to caregivers who are not properly trained in safely maneuvering such heavy objects.
Handling a patient in a conventional bead bed is also plagued with difficulty, largely because caregivers must reach down into the tank and lift the patient up or out for handling. The teaching of U.S. Pat. No. 5,008,965 attempted to address this situation by providing separate air bladders within the bead compartment for displacing the beads upwardly, hence, lifting the patient relative to the tank. Still others, such as illustrated in U.S. Pat. No. 5,036,559 (ELEXIS), have attempted to address the problem by providing deflatable or otherwise collapsible tank walls instead of the traditionally rigid walls. Related difficulty is faced by the patient who is attempting to sit up in such beds. Although foam wedges and the like are often used to help prop up the patient, props present the obvious downfall of interfering with the therapeutic benefits of the bead surface. Using props also renders such products more difficult to manipulate than conventional hospital beds which have automatic bed functions such as head-up, Trendelenberg and the like.
Air beds, on the other hand, eliminate many of these problems. Not only are the mattresses of the air beds lighter due to the lighter supporting medium (i.e., air versus beads), but lighter-duty supportive equipment and structural members are needed as well. Moreover, air beds permit many of the user-friendly features of standard hospital beds, such as sit-up, Trendelenberg, and the like, not to mention retractable side rails and radioluminescence. The extra space beneath the patient surface also allows not only for extra storage, but also for adding accessory therapeutic units such as percussion and hyper-hypothermia treatment.
Many other advantages and disadvantages of low-air-loss beds and air fluidized bead beds will be understood by those of ordinary skill in the art, especially after reviewing this specification.
SUMMARY OF THE INVENTION
It is a fundamental object of the present invention to improve over the prior art, including to provide a therapeutic patient treatment bed and related methods which facilitate the care and comfort of bed-ridden patients, while simultaneously addressing the complications associated with immobility.
This and other objects are addressed by providing a therapeutic patient treatment bed wherein the patient support surface comprises an air cushion with integral fluidized bead surfaces. The beads may be fluidized by the same air flow as is utilized for inflating the patient support air cushion. Unlike many prior bead beds, the invention described herein allows the patient support surface to be positioned as desired, providing a lightweight, full-featured fluidized bead bed. Moreover, because air flow can be compartmentalized into a plurality of air bags or cushions, each with independent bead surfaces, the present invention also enables a wide variety of additional surface therapies not previously available with bead beds, including pulsation, percussion, and kinetic therapies. The fluidized bead surfaces may also be detachable for facilitating infection control procedures.
Many other objects, features, variations and advantages of the invention will be evident from a review of the further descriptions herein, particularly when reviewed by one of ordinary skill in the art with the benefit of the accompany drawings, appended claims and the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a patient treatment bed 20 (absent its cover sheet) configured and operatively inflated for typical use, which comprises a presently preferred embodiment of the present invention.
FIG. 2A is a perspective view of an air bag 21 of the bed 20 shown in FIG. 1 .
FIG. 2B is a partial cross-sectional view of the airbag 21 shown in FIG. 2 A.
FIG. 3A is a partially-exploded perspective view of an air bag 171 , which is an alternate embodiment of the air bag 21 shown in FIGS. 2A-B.
FIG. 3B is a partial cross-sectional view of the air bag 171 shown in FIG. 3A, including its fluidized bead pouch 172 , taken along lines 3 B— 3 B in FIG. 3 A.
FIG. 4A is a partially-exploded perspective view of an air bag 121 , which is a second alternative of the air bag 21 shown in FIGS. 2A-2B.
FIG. 4B is a cross-sectional view of the airbag cap 130 as shown in FIG. 4 A.
FIG. 4C is a partial cross-sectional view of the main part 129 of the air bag 121 shown in FIG. 4 A.
FIG. 4D is a partial cross-sectional view of an alternative embodiment 129 ′ of the main part 129 shown in FIG. 4C, from the same perspective as shown in FIG. 4 C.
FIG. 5 is a perspective view of an alternate embodiment 320 of the invention.
FIG. 6 is a more detailed perspective view of the mattress 320 of the alternate embodiment shown in FIG. 5, absent its frame 319 and cover sheet 380 .
FIGS. 7A and 7B are views of the unassembled upper wall 27 and filter sheets 41 and 42 of bead pouch 22 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although most aspects of the invention described and claimed herein could be embodied in many different types of beds, mattresses and/or cushions, the bed 20 shown in FIG. 1 is considered to be a presently preferred embodiment of that invention. Referring to FIG. 1, there is shown a patient treatment bed 20 that is uniquely suited for treatment of burn patients and other patients subject to extensive recuperative periods. Bed 20 includes a frame 19 supporting a plurality of patient support air bags 21 , which are uniquely adapted with bead pouches 22 . One fairly basic aspect of the invention can be embodied in one or more cushions such as patient support air bags 21 , operatively associated with one or more fluidized bead containment pouches 22 and means for fluidizing the same, all of which may or may not be mounted on a frame such as frame 19 .
One advantage of the invention is that it can be implemented as a relatively simple upgrade to a pre-existing air support. Typically, the only change needed will be to replace one or more of the air cushions of the pre-existing support with new cushions that are specially-adapted to implement the present invention. In some cases, however, it may be that additional blower capacity is needed due to the relatively large amount of air required to fluidize the bead pouches 22 as compared to the amount of air that may be needed to sustain inflation of the pre-existing support. Those of skill in the art will understand how to increase blower capacity, such as by adding an additional blower or redirecting existing blowers. The term “host platform” is used in this description to refer to the preexisting support. Modifications to the host platform may be described in detail, whereas unmodified details will be described only to the extent desired for reference.
The host platform 20 may be any of a number of commercially available patient air supports, preferably low-air-loss patient treatment beds. Host platform 20 of the preferred embodiment comprises a low-air-loss bed presently commercialized under the trademark “KINAIR III,” commercially available from Kinetic Concepts, Inc. of San,Antonio, Tex. (“KCI”). The KINAIR III bed is described in substantial detail in U.S. Pat. No. 5,005,240, dated Apr. 9, 1991, incorporated herein by this reference. Other suitable host platforms include, but are not limited to, those marketed by KCI under the trademarks “HOMEKAIR,” “THERAPULSE” and “BIODYNE II.” All of these platforms are commercially available from Kinetic Concepts, Inc. The THERAPULSE bed is described in substantial detail in U.S. Pat. No. 5,044,029, dated Sept. 3, 1991, incorporated herein by this reference. The BIODYNE II bed is described in substantial detail in U.S. Pat. No. 5,142,719, dated Sep. 1, 1992, also incorporated herein by this reference. Other host platforms might include wheelchairs with therapeutic air cushions or stand-alone therapeutic air mattresses mounted on any desired support.
As suggested above, the principal difference between bed 20 and a commercially available KINAIR III bed is the adaptation of its air bags 21 to include fluidizable bead pouches 22 . A simple form of such an adapted air bag 21 can be made by cutting a rectangular hole in the upper surface of an existing KINAIR III air bag and sewing a similarly-shaped, air-permeable bead pouch 22 over the hole. An air bag 21 made in such manner is shown in FIGS. 2A&B, as part of a presently preferred embodiment of the invention. Conventional stitching techniques can be used to provide a smooth outer surface for the adapted bag 21 . For instance, although it is stated to sew the bead pouch “over” the hole, it will be understood by those of skill in the art that an acceptable technique for minimizing exposed edges would be to sew (or otherwise attach) the pouch from the inside of air bag 21 , around the perimeter of the rectangular hole 39 in the air bag's upper surface 27 . Conventional seam-sealing techniques can also be used to minimize loss of air through the seams 40 a - 40 d , as well as any other seams in bag 21 , to minimize any unnecessary air leaks in the air bag 21 . Such a construction enables the air bag 21 enclosure to serve as an effective plenum chamber for fluidizing the beads within the bead pouch 22 ; the space 48 enclosed by air bag 21 is, hence, referred to as the “plenum space” 48 .
Referring to FIGS. 2A&B, each adapted air bag 21 includes bead pouch 22 formed integrally therein. Such integral construction ensures simplicity of manufacture and use, while minimizing any excessive loss of air, as might be more likely with a two-part construction. The air bag 21 can be disinfected through laundering with a dilute bleach solution in the same manner as conventional air bags. Due to the inclusion of the bead pouch 22 , adequate drying of the air bag 21 may require operative connection of the air bag 21 to a host platform. Such operative connection helps dry the beads by virtue of the air blowing through beads 200 . Although the exact length of time needed to dry the beads 200 may vary, twenty-four hours will generally be more than adequate. The drying time should be however long it takes to dry the beads so they can be adequately fluidized, while also respecting any infection control concerns.
One alternative embodiment of air bag 21 is described further herein as air bag 171 , with reference to FIGS. 3A&B. Such alternative air bag 171 utilizes a bead pouch 172 that is adapted to be removed from a pocket 198 ′ in the end wall 175 of the air bag 171 . The pouch 172 , therefore, can be removed and disinfected or disposed of separate from any low-air-loss components. Another alternative embodiment of air bag 21 is described further herein as air bag 121 , with reference to FIGS. 4A-D. Such alternative air bag 121 also utilizes a two-part construction for its bead pouch 122 . Air bag 121 is different, though, in that its bead pouch 122 is embodied in a removable cap 130 for air bag 121 . In such alternative, the bead containment pouch 122 is removed from the air bag 121 by removing the cap 130 as a whole, so that the pouch 122 can then be disinfected or disposed of separate from any low-air-loss components. Other embodiments are also disclosed.
Each of the air bag embodiments 21 , 171 , 121 and 121 ′ are made from the same basic fabrics—a low-air-loss material and a filter sheet material. The low-air-loss material in the preferred embodiment is a polymer-coated nylon material commercially available under the trademark “GORE-TEX” from W. L. Gore & Associates, Inc. of Elkton, Md. Such low-air-loss material has very little air permeability yet has a moisture vapor transmission rate in excess of 4700 g/m 2 /24 hours. In the preferred embodiment, the filter sheet fabric is constructed of 63-micron monofilament polyester fiber thread with 40-micron nominal mesh opening and 15% open area. The filter fabric is commercially available from Tetko, Inc. of Briarcliff Manor, N.Y. One possible alternative that might be considered is to use a similar multifilament fabric rather than the monofilament. Other suitable alternatives will be evident to those of skill in the art.
Regarding the construction of the air bag embodiments 21 , 171 , 121 and 121 ′, there are several common elements. Although most of such common elements are also common with the commercially-available KINAIR III air bags, brief reference is made to each of such common elements (referring to reference numerals used in FIG. 2 A). Air bag 21 , to begin with, is formed to have the general shape (when inflated) of a rectangular prism, as shown in FIG. 2 A. Air sac 21 has six generally rectangular walls 23 - 28 , which may be considered as three pairs of opposed similar walls: opposite side walls 23 and 24 , opposite end walls 25 and 26 , and opposite top and bottom walls 27 and 28 . Each of such walls 23 - 28 is formed primarily of the low-air-loss material referenced above, cut in pieces that are stitched (or otherwise joined) to adjacent pieces along their adjoining edges. As will be understood by those of ordinary skill in the art, particularly with reference to a commercially-available KINAIR III air bag, certain walls may actually be formed from the same piece of material as another wall, while other walls may be formed of a combination of one or more pieces of material. The edges between two adjoining walls, hence, may not in actuality constitute seams between fabric pieces. The sheet of material which forms the top wall 27 , for instance, actually extends beyond each of its edges 27 a - 27 d shown in FIG. 2 A. Fabric-gathering seams and conventional stitching techniques are used to generally form each of the four corners 27 e - 27 h of upper wall 27 . That same piece of fabric which forms upper wall 27 , further, extends partially down each of the opposite side walls 23 and 24 and each of the opposite end walls 25 and 26 to a seam (not shown) with an adjoining piece of fabric slightly above the level of baffle 127 . Again, such sewing techniques and the general construction for the various walls 23 - 28 of air sac 21 will be evident to those of ordinary skill in the art, particularly with reference to commercially-available air sacs. It is also noted that in certain alternative embodiments it may be desired to form the air cushions in different shapes, such as the cut-out shape of the BIODYNE air sacs, or the relatively flat (or “low profile”) shape of the air sacs used in products such as the DYNAPULSE product, also available through Kinetic Concepts, Inc.
Still referring to common elements of the air bag embodiments 21 , 171 , 121 and 121 ′, as well as the KINAIR III air bags, each air bag 21 , 171 , 121 and 121 ′ also has a post 43 and an air inlet 44 operatively secured to the bottom wall 28 thereof, as is standard for KINAIR III air bags, for attachment to the host platform 20 . Such hardware 43 and 44 are standardly employed in a manner which allows entry of air into a space 48 enclosed by the main part 29 of air bag 21 , such air being blown by blowers such as standardly included in the host platform 20 . Each air bag 21 further comprises a baffle 34 also constructed of low-air-loss fabric, although less costly alternative fabrics may be desired as air permeability and low skin shear benefits are not necessary for baffle 127 . Baffle 127 functions to ensure the desired prismatic shape of the inflated bag 21 (i.e., that of a rectangular prism). The baffle 127 is sewn, or attached by other equivalent means, at its edge 35 to the inside surface of the front side wall 23 of the air bag 21 . The baffle 127 is similarly sewn, or attached by other equivalent means, at its edge 36 to the inside surface of the rear side wall 24 of the air bag 21 . The end-to-end length of baffle 127 as measured from edge 37 to edge 38 is sufficiently less than the end-to-end length of air bag 21 , as measured from end 25 to end 26 . That shorter length allows substantial air flow around the baffle. Said air flow is as depicted by arrows (including arrows 33 a-c in FIGS. 2 A&B). The preferred embodiment provides a minimum 4-inch opening between end wall 25 and edge 37 as well as end wall 26 and edge 38 .
Further understanding of the hardware 43 - 44 and sewing techniques utilized in the preferred embodiment may be gathered to some extent with reference to U.S. Pat. No. 5,062,171, dated Nov. 5, 1991, incorporated herein in its entirety by this reference.
Referring to FIG. 2B, there is shown a sectional view of a fluidized bead containment pouch 22 (viewed on the vertical plane 2 B— 2 B indicated in FIG. 2 A). The bead containment pouch 22 is substantially rectangular from above (rectangular shape generally visible in FIG. 2A) and comprises rectangular top and bottom filter sheets 41 - 42 . Unless sheets 41 and 42 can be readily made together as a seamless pouch, sheets 41 and 42 are sewn or otherwise joined to each other around their perimeters (i.e., along edges 40 a - 40 d ) in a substantially sealed manner so as to form a substantially closed pouch for containing beads 200 . In the preferred embodiment, filter sheets 41 and 42 are constructed of the same filter sheet fabric as described previously herein. By making pouch 22 seamless or by providing sealed seams 40 a-d , leakage of beads 200 from pouch 22 can be minimized. Once filled with beads 200 to the desired extent and sealed closed, the pouch 22 is then sewn (or otherwise attached) to the upper wall 27 of air bag 21 , around the perimeter of hole 39 .
The preferred size of upper and lower filter sheets 41 and 42 (and, hence, pouch 22 ) will be best understood from the description of the preferred method for making pouch 22 . With reference to FIGS. 7A & 7B, there is shown a plan view of the cut-outs for the upper wall 27 and bead pouch 22 , respectively. As mentioned, the rectangular hole 39 , which is cut out of upper wall 27 , is a substantially rectangular hole. The preferred dimensions of such hole are 5 inches (along edges 39 c & d of hole 39 ) by 23 inches (along edges 39 a & b of hole 39 ). The pouch 22 begins at a single piece 86 of filter sheet fabric cut in the shape as shown in FIG. 7 B. The overall dimensions of piece 86 are nominally 49 inches (in length) by 6½ inches (in width), although lower sheet 42 is tapered in its primary dimension to 4 inches. The dimensions 401 - 406 of piece 86 are 15½, 4½, 4½, 4, 6½ and 24½ inches, respectively. Once piece 86 is cut as shown in FIG. 7B, the piece is folded al center line 87 and edges 41 a & b are sewn (inside out) and sealed to edges 42 a & b to give pouch 22 its basic shape. Then, the assembly is pulled right side out and filled with beads 200 (not shown in FIG. 7B) through an opening formed between edges 41 c and 42 c , after which the same edges 41 c and 42 c are sewn and sealed. The seams formed by the unions of edges 41 a-c and 42 a-c , and a final edge formed by the fold 87 , are then sewn and sealed to upper wall 27 along the perimeters of hole 39 . The result produces a bead pouch 22 that is slightly tapered along its midsections. Given the amount of material used by seams (approximately ¼ inch for each seam), the final width of lower filter sheet 42 which is exposed to the beads 200 is approximately 3 inches at its narrowest point and 5 inches at its longitudinal ends adjacent to seams 40 c & d . The remaining dimensions of FIGS. 7A&B are as shown therein.
The resulting size is generally such that in every air bag 21 on bed 20 included a pouch 22 , then the entire patient could be supported on the bead pouches 22 . Certain ones of air bags 21 may have differently sized pouches 22 , or may not have pouches at all. In the bed 20 illustrated in FIG. 1, for instance, head air bags 98 have shorter pouches (only about 10 inches long), and the last air bag 99 does not have a pouch 22 at all. Further, air bags with and without pouches 22 can be mixed and matched along the length of the bed 20 to achieve a desired surface. For patients with local bums, for instance, the fluidized bead surface may be limited to that region of the patient where the bum is located, while the rest of the patient is supported on conventional KinAir III air bags. In other cases, the bead surface may be limited to the seat section as that is where weight concentration is greatest. In any case where pouches 22 are included in a given air bag 21 , however, the upper sheet 41 is preferably about 2 inches wider than the lower sheet 42 , for reasons mentioned elsewhere herein.
The beads 200 contained in each bead pouch 22 are preferably medical grade microspheres of the type commonly employed in air fluidized bead beds. Such beads range in size from 50 to 150 microns in diameter and are commercially available from a number of sources, including Potters Industries, Inc. of Carlstadt, N.J. A single bead pouch 22 preferably contains about a two pounds of beads, although quantities of bead material from ¼ to 30 pounds or more per air bag may be suitable. The bead pouch 22 is also not completely filled, so that the beads are free to fluidize therein. Consequently, when air flows through bead pouch 22 without a patient supported thereon, the upper filter sheet 42 tends to billow upwardly, forming an air space 201 above the beads 200 .
The pouch 22 , hence, is integrated with air bag 21 in a manner that encourages air flow from space 48 , through pouch 22 , tending to fluidize any quantity of beads 200 within pouch 22 . Because the low-air-loss GORE-TEX fabric has very low air permeability, the air that inflates the air bag 21 tends to flow, more particularly, from plenum 48 , through the lower filter sheet 42 , through the beads 200 and excess space 201 , and on through the top filter sheet 41 , as suggested by arrow 33 c . By using the same air for bead fluidization as is used to inflate the air bag 21 , greater fluidization is achieved in those pressure zones in which air bags are inflated to higher pressures, which usually occurs with those air bag zones supporting heavier body portions (such as a patient's seat section). Hence greater fluidization is provided where it tends to be needed most—beneath the locations where the interface pressures are also greatest.
It is also noted, however, that lower filter sheet 42 may require some degree of air flow restriction in order to prevent excessive loss of air from within air bag 21 . The balance of the amount of air flow that will be desired through lower filter sheet 42 will depend on a variety of circumstances, including the blower capacity of the host platform 20 , the volume of beads 200 in each air bag 21 , and the number of air bags 21 which are adapted with bead pouches 22 . In one preferred embodiment, it has been found that air-impermeable strips 89 a & b may be adhered to the outer surface of lower filter sheet 42 to reduce and concentrate air flow through lower filter sheet 42 . Such strips 89 a & b are preferably composed of commercially available sealing tape such as is used for waterproofing grommets in the clothing industry. Suitable sealing tape is a ¾-inch Teflon sealing tape commercially available through the W. L. Gore Company. Strips 89 a & b (and similar strips sealing seams 40 a & b ) preferably around the entire length of bead containment pouch 22 on the lower surface of lower filter sheet 42 . Such configuration of sealing strips 89 a-d leaves three sections 88 a-c of lower filter sheet 42 unobstructed for free flow of fluidizing air therethrough. Due to the 3-inch width of lower filter sheet 42 , sections 88 a-c end up being three strips of unobstructed filter sheet running the length of bead containment pouch 22 . Each of strips corresponding to sections 88 a-c are approximately ¼-inch wide, although that width dimension will flare toward the ends 40 c and 40 d of bead containment pouch 22 as the bead containment pouch itself flares as well.
It is noted that once the air has passed through pouch 22 , its direction of flow is determined based on other factors. For instance, if a conventional, high-air-loss cover sheet is used, some of the fluidizing air will pass through the cover sheet while the remainder will be diverted to the sides of the bed 20 by that cover sheet. If a cover sheet is not used, then more of the fluidizing air would tend to rise upwardly around the patient's body.
It is also noted that the profile shape of the pouch 22 (i.e., the cross-sectional shape such as shown in FIG. 2B) depends on a variety of factors. Such factors include but are not limited to the size of the bead pouch 22 , the relative porosity of the filter sheets 41 and 42 , the air pressure within plenum space 48 , the quantity of beads 200 within pouch 22 , and the patient weight. In many cases, the bead pouch 22 tends to arch upwardly due to the pressure within air bag 21 , in contrast to the cigar-like shape shown in FIG. 2 B. Two practical concerns with this occurrence are (i) that the beads 200 might migrate downward at the sides of the pouch 22 due to gravity, and (ii) that the arching might restrict free fluidization by compressing the beads between the upper and lower filter sheets 41 & 42 . One contemplated way of reducing such concerns is the inclusion of a vertical baffle (not shown) spanning between the lower filter sheet 41 and the horizontal baffle 34 , in the same general manner as illustrated in FIG. 4 D. Another technique that is preferred is to make the upper filter sheet 41 wider and longer than the lower sheet 42 (approximately 2 inches in each dimension) so that the lower sheet 42 tends to be more taut (and, hence, less arched) than the upper sheet 41 . Yet another technique is to increase the volume of the beads 200 in a given air bag 21 , such as by starting the bead pouch 22 at the level of baffle 34 , with beads filling up roughly the entire upper third of the air bag 21 .
Although simple, the construction of air bag 21 might be found to be less than ideal for disinfecting on a routine basis, Referring to FIGS. 3A-4D, alternate embodiments of air bag 21 are shown which allow detachment of bead pouch 22 (or its equivalent) so that the bead containment pouch may be disinfected separately.
The first of such alternatives is shown in FIGS. 3A&B as air bag 171 . Air bag 171 is adapted with a removable bead pouch 172 . The removable pouch 172 consists only of its upper and lower filter sheets 191 and 192 and the beads 200 contained therebetween. Rather than being permanently sewn to air bag 171 , pouch 172 is inserted within (and removable from) a pocket 198 ′ near the upper wall 177 of air bag 171 . Access to the pocket 198 ′ is provided through an opening 199 in the end wall 175 of the air bag 171 . For minimizing loss of air pressure through opening 199 , the opening 199 may be covered and/or sealable by a Velcro flap (not shown) or the like. The pocket 198 ′ is formed of two layers of filter sheet material 197 and 198 just beneath the upper wall 177 of the air bag 171 . Layers 197 and 198 are joined by conventional techniques along the opposite edges 177 a and 177 b of upper wall 177 to form pocket 198 ′. The upper wall 177 is also provided with a rectangular filter sheet panel 189 for allowing free flow of air through bead pouch 172 . An alternative of air bag 171 excludes the upper filter sheet layer 197 of pocket 198 ′.
With such construction, the pouch 172 can be removed and disinfected or disposed of separate from the low-air-loss components of air bag 171 . Such low-air-loss components can then be disinfected using standard laundering techniques for air bags. The bead containment pouch 172 may be disinfected by infection control techniques which are standard and well-known in the art for fluidized bead systems. Such infection control procedure may involve destroying the filter sheet layers 191 and 192 of the pouch 172 and pouring the beads 200 through a sieve screen into a conventional decontamination tank. Decontamination can then be achieved by a thermal process of heating the beads to 122° F. for at least 24 hours. Further benefits of such removable conformation of bead pouch 172 will be apparent to those of skill in the art.
A second basic type of alternative to air bag 21 is shown in FIGS. 4A-C as air bag 121 . Like air bag 171 , air bag 121 also has a two-part construction adapted with a removable bead pouch 122 to facilitate infection control. The removable pouch 122 , however, is embodied in a removable cap 130 that fits over the top of a main part 129 of air bag 121 . The main part 129 can be disinfected through laundering in the same manner as with conventional air bags, and the cap 130 can be disinfected separately. Although the particular technique used for disinfecting the cap should be chosen based on the effectiveness of each technique, it is presently thought that adequate disinfection may be achieved by placing the entire cap 130 into a conventional microsphere decontamination unit, together with a separate bead lot. Such a decontamination is intended to raise the temperature of the cap above 120° F. for more than a 24-hour period. Other disinfection techniques, such as chlorination, gamma radiation and/or autoclaving, may be considered as additional alternatives.
The main part 129 of air bag 121 is much like the construction of a standard KinAir III air bag, except that the main part 129 includes a filter sheet panel 147 and Velcro tabs 131 a-d . Cap 130 includes the bead containment pouch 122 and Velcro tabs 132 a-d . The shape and construction of cap 130 is such that it fits snugly over the main part 129 when the main part 129 is inflated, with tabs 132 a-d positioned to mate with tabs 131 a-d for releasably securing the cap 130 in place. Once so positioned, cap 130 positions bead pouch 122 over the filter sheet panel 147 , so that air escaping through panel 147 is directed through pouch 122 , tending to fluidize the beads 200 therein. To optimize fluidization, Velcro tabs 132 a-d and 131 a-d may be enlarged or replaced with other connections providing a better seal. Improving such seal ensures that the only significant escape for air from the air bag 121 is through bead pouch 122 . The size of the panels 147 and pouch 122 is much the same as that of the pouch 22 in the first embodiment, although panel 145 is preferably narrower than pouch 122 .
With reference to FIG. 4D, an alternative construction of main part 129 is shown, designated as 129 ′. Particularly, main part 129 ′ includes a vertical baffle 149 coextensive with the conventional horizontal baffle 227 ′. Vertical baffle 149 spans is joined by stitching between the centerline 150 of panel 147 ′ to form a trough-like crease along the top of main part 129 ′. Such trough-like crease not only tends to bias beads 200 toward the centerline 150 , but its stitched joinder increases fluidization (by introducing stitch holes in panel 147 ′) along the centerline 150 where the beads 200 are drawn.
Referring to FIGS. 5 & 6, there is shown an alternate embodiment 320 of the bed 20 shown in FIGS. 1-2B. Bed 320 generally consists of an air mattress 318 (and related components) mounted on a standard bed frame 319 . The mattress 318 is sectioned into three basic support cushions 318 a , 318 b , and 318 c , as is standard for a variety of mattress and mattress overlay products. Each basic support cushion 318 a, b or c is supplied with air flow from a standard air supply unit 315 through corresponding supply hoses 316 a-c . Each cushion includes a series of six vertical baffles (not numbered) to ensure retention of a relatively flat shape. Examples of such patient support mattress systems are found in the commercially available FIRSTSTEP SELECT, HOMEKAIR DMS and DYNAPULSE products, each commercially available through Kinetic Concepts, Inc. The particular system illustrated in FIGS. 5&6 is a modified FIRSTSTEP SELECT unit. As with the previously-described embodiments, the mattress 318 is substantially the same as the commercial version of that product. The only significant difference being the addition of fluidizable bead containment pouches 322 a-c and any additional blowers that might be needed (if any) to fluidize the same. As will be evident to those of skill in the art, the size of the bead containment pouches 322 a-c can be varied as desired. For instance, in FIG. 6, it is shown that the size of the pouch 322 b positioned for supporting the seat section of a patient is larger than the other two pouches 322 a & c . Thus, greater therapy can be provided in the seat section (or in any other areas) where the therapeutic need is greater. The particular method of adapting the cushions 321 a-c with an appropriate number of bead containment pouches 22 is not critical but will be understood from an understanding of the preferred embodiment of air bag 21 . Another variation (not shown) of bed 320 can be made by replacing substantially all of the top surface of the mattress 318 with a single fluidizable bead pouch.
The invention described herein allows combination of a fluidized bead patient support surface, well-known in the art to be an ideal patient support surface, with the advantages of low-air-loss beds. Such advantages will be evident to those skilled in the art and include, but are not limited to, vertical and/or articulated displacement of the patient support surface, side to side rotation of the patient, automatic percussion of the patient's chest area, and built-in scales, all of which are well-known in the art and may be described in the literature available for the commercial products KFNAIR III, HOMEKAIR, THERAPULSE and BIODYNE II.
Unique advantages afforded by each of the many possible host platforms 20 for implementation of the invention described herein will also be apparent to those skilled in the art. Said advantages will generally vary with the basic capabilities of the chosen host platform 20 . One of the more interesting has been found by using air bags like air bag 21 to replace the air bags of a THERAPULSE bed, commercially available through Kinetic Concepts, Inc. Utilization of the THERAPULSE bed as host platform 20 allows the caregiver to establish various pressures within air bags 21 corresponding to differing regions of the patient's body, and also allows automatic pulsation of bead fluidization. A caregiver can, thus, vary the level of fluidization for different parts of the body, and also pulse that fluidization as well. Although the air bags 21 as a whole generally become softer at lower pressures, the beads 200 generally become more stiff with lower degrees of fluidization. Hence, pulsing the fluidization with the THERAPULSE as host platform 20 will cause the beads 200 in the air bags 21 to vary from soft, to stiff, to soft, and so on. Not only will adjacent air bags 21 vary in opposite phase (as is normal for THERAPULSE pulsation), but stiffness of the bead pouch 22 surface will vary in opposition to the air pressure in the air bag 21 as a whole.
Another alternative embodiment, which is not shown in the drawings, is adapted to provide a dedicated air flow for purposes of fluidizing the beads 200 in each air bag 21 . The concept for this alternative is to allow separate control of the air supply directed to the plenum used for fluidizing the bead pouch 22 and to reduce the size of that plenum chamber. With a smaller, separately controlled plenum, the pressure of the air fluidizing the beads can be increased to achieve greater fluidization without increasing the pressure of the air bag 21 as a whole. To do this, a separate inflatable chamber is defined within air bag 21 directly adjacent the bead pouch 22 . The inflatable chamber serves as the plenum for fluidizing the bead pouch 22 , and a separate air supply is directed to that plenum. The construction of the separate plenum within the air bag 21 would be designed in any manner desired, although the simplest approach uses the same low-air-loss material as the remainder of air bag 21 . The separate dedicated air flow might be directed through a separate air inlet for the air bag 21 . A collapsible air conduit within air bag 21 would also serve to direct the flow of air from the second air inlet to the dedicated plenum. Although conventional air conduit may be suitable, a fabric conduit (also formed of sealed low-air-loss material) may be adequate to serve this purpose. By providing a separate air flow dedicated to fluidization, the inflation of the air bag 21 as a whole could, thus, be varied independently from the fluidization of the bead pouch 22 . Similar adaptations of the other alternative embodiments could also be made.
Many other alternatives, variations and modifications of the present invention will be evident to those of skill in the art and are contemplated to fall within the scope of the present invention. Although the present invention has been described in terms of the foregoing preferred and alternate embodiments, this description has been provided by way of explanation only and is not to be construed as a limitation of the invention, the scope of which is limited only by the following claims and any amendments thereto. | A therapeutic treatment bed with features to enhance the care and comfort of burn patients and others subject to extensive recuperative periods. Among the features are patient engaging fluidized bead surfaces integral with the upper surfaces of air cushions provided by an air bed. Detachable conformation of the fluidized bead surfaces is also provided. | 0 |
FIELD OF THE INVENTION
[0001] This invention relates to a coupling assembly for interconnecting two members, and more particularly, to a self-locking, self-bonding, rigid coupling assembly for interconnecting a pair of tubular conduit members wherein the coupling assembly has a releasable locking feature for connection and disconnection.
BACKGROUND OF THE INVENTION
[0002] The owner of the current invention is also the owner of a number of previous patents for couplings used to interconnect confronting ends of fluid carrying conduits in an aircraft. These patents include the U.S. Pat. Nos. 5,871,239; 6,050,609; and 6,073,973. Characteristics common to each of the inventions disclosed in these patents are coupling devices that include a plurality of threaded members which are rotatable in a locking direction, and rotatable in an opposite unlocking direction. Locking of the couplings is achieved by locking tabs that are received in corresponding notches/reliefs. A resilient member is provided to ensure that the couplings remain in a locked position when the coupling is tightened to a predetermined extent during rotation in a locking direction. Visual indicia is provided to indicate when the couplings have been placed into locking engagement.
[0003] Nadsady U.S. Pat. No. 3,669,472; Gale et al. U.S. Pat. No. 4,808,117 and Gale et al. U.S. Pat. No. 4,928,202 each disclose a coupling device in which the tightening of the coupling parts is readily accomplished, but accidental loosening is restrained by spring fingers carried by one of the coupling parts which engage indentations or notches on the other coupling part in such a manner as to favor relative rotation of the coupling parts in the tightening direction, while restraining with greater force the rotation of the coupling parts in the opposite unlocking direction.
[0004] Cannon U.S. Pat. No. 3,999,825; Filippi U.S. Pat. No. 4,008,937; Mahoff U.S. Pat. No. 4,249,786 and Gale U.S. Pat. No. 4,346,428 each disclose a coupling with one or more toggle latches which snap into a positive locking position.
[0005] Spinner U.S. Pat. No. 4,285,564 discloses a coaxial plug connector wherein a first ring of axially pointed teeth is provided around the circumference of a cap ring. A first connector has a ring with teeth for engaging the teeth on the cap ring. The cap ring is withdrawn axially against the force of a biasing spring when the coupling is rotated to a different position. The cap ring is released and the spring urges it into locking engagement with the tooth ring. Thus, accidental rotation of the cap ring relative to the first connector is prevented.
[0006] Runkles et al. U.S. Pat. No. 4,881,760 discloses a coupling with locking tines having visible indicia for determining whether or not the tines are in locked position.
[0007] Runkles et al. U.S. Pat. No. 4,900,070 discloses a coupling with spring biased rotatable locking tines.
[0008] Many prior art coupling devices are specifically designed so that the couplings are able to maintain a fluid tight connection between the conduits even when the joined conduits are misaligned. These couplings typically use multiple sealing members or o-rings in at least two or more coupling components to provide some amount of resiliency in the coupling allowing misalignment. For couplings used in aircraft applications, this misalignment can be caused by live loading conditions wherein vibrations from the aircraft and other forces cause periodic shifting of the conduit members. This misalignment can also be caused by static forces, such as may be attributed to the particular orientation of the conduit members when they are assembled in the aircraft.
[0009] In the construction of an aircraft, there are constraints in available spaces to run conduits for hydraulic and electrical lines. In such constrained spaces, it is very difficult to provide the necessary support brackets to support the conduits. More particularly, when it is necessary to make a connection between confronting ends of conduit members, the constrained spaces make it even more difficult to install the couplings and to provide support brackets near the couplings. Although many couplings as mentioned above have the capability to provide a sealed connection with misaligned conduits, misalignment is avoided in most all aircraft applications as a safety precaution to prevent fuel leakage for fuel lines.
[0010] Therefore, there is a need for a rigid connection that can be established between confronting conduit members thereby eliminating the need for further structural support to join the conduit members, yet the connection should be lightweight, capable of transmitting shear loads between the conduit members, and of a small enough size that the coupling can fit within the constrained spaces. Additionally, it is highly advantageous to provide electrical continuity between the interconnected conduits. Electrical continuity ensures that there will not be a buildup of an electrostatic charge on a first conduit relative to the second interconnected adjacent conduit. As a result, there is no potential difference between joined conduits or between a conduit and another reference surface, thereby eliminating the creation of an electrical spark that otherwise could ignite vaporized fuel present in the conduit members.
SUMMARY OF THE INVENTION
[0011] In accordance with the present invention, a threaded coupling assembly is provided that is self-locking, self-bonding, and provides a rigid self-supporting connection between confronting ends of conduit members.
[0012] In a preferred embodiment of the present invention, the coupling is an assembly of components including a threaded flange connected to a first conduit member, a standard flange connected to a second conduit member, and a lock nut group that interconnects the standard flange to the threaded flange. In the rigid connection, a single o-ring is utilized to seal a continuous passageway through the first and second conduit members. The lock nut group connects to the threaded flange by a threaded connection, wherein the threads of the lock nut group are clocked with respect to the threads on the threaded flange. A pre-determined amount of rotation of the lock nut group with respect to the threaded flange results in alignment of locking features on the lock nut group and the threaded flange. Once aligned, the locking features snap fit into a locking engagement.
[0013] The coupling creates a rigid connection. Looseness or flexibility of the connection between the first and second conduit members is limited by a number of factors. One factor is the manor by which the threaded flange and standard flange connect to their respective conduit members. Preferably, these connections are swage type connections so that stiffness and rigidness is maintained. Another factor is the interface between the standard flange and lock nut group by use of a close tolerance fit between the opening of the lock nut group that receives the standard flange. A flat washer or bushing is placed in the opening, and rotation of the lock nut group in the locking direction captures the bushing between an interior shoulder of the lock nut group and an external shoulder of the standard flange. Other factors include use of a single o-ring, and the threaded connection between the lock nut group and the threaded flange.
[0014] When the coupling assembly is to be placed in the locked position, the locking features in the form of complementary peripheral facing surfaces are provided on the threaded flange and on the lock nut group so that when the lock nut group is drawn axially toward the threaded flange by rotatably threading the lock nut group, the complementary facing surfaces snap into the locked position.
[0015] The complementary peripheral facing surfaces in the preferred embodiment include at least one notch or relief formed on the lock nut group, and a corresponding at least one projection or tab formed on a peripheral surface of the threaded flange The predetermined amount of rotation of the lock nut group with respect to the standard flange results in positive engagement of the tab(s) with corresponding notch(es).
[0016] Visual and audio indicators may be provided to confirm positive engagement. A visual indicator in the form of an indicator stripe may be placed on the exposed peripheral surface or rim of the threaded flange that allows the user to observe whether the lock nut group has been fully installed over the threaded flange. The indicator stripe is located on the part of the rim of the threaded flange which is covered by the lock nut group once the lock nut group is fully screwed over the threaded flange. For the audible indicator, a distinct clicking sound is present due to a biased arrangement of the components within the lock nut group, wherein a nut body and a lock ring of the lock nut group are biased with respect to axial movement along the longitudinal axis. A biasing member in the form of a wave spring maintains a spring force to maintain the lock nut group in positive engagement with the threaded flange when in the locked position. The coupling is unlocked by pulling the lock nut group so that the tab(s) are disengaged from the corresponding notch(es), and then rotating the lock nut group in an opposite unlocking direction.
[0017] The lock nut group includes a number of parts, to include a split retainer, a lock ring, the wave spring mentioned above, and a nut body. The split retainer is retained within the lock ring by an annular slot or shoulder formed on the interior surface of the lock ring. The wave spring resides within a specified gap between the lock ring and nut body. The wave spring is delimited in axial movement on one side by the split retainer, and is retained on the other side by an interior shoulder of the nut body.
[0018] A plurality of keys or projections are formed on the interior surface of the lock ring and are placed in mating engagement with a corresponding plurality of notches or keys formed on the outer surface or rim of the nut body. Thus when the lock nut group is assembled, the lock ring is axially or longitudinally displaceable with respect to the nut body to the extent that the wave spring can be compressed and decompressed within the fixed space or gap between the lock ring and nut body.
[0019] The leak proof path or passageway that is maintained between the first and second conduit members is achieved by adequate compression of the o-ring which is positioned between a facing surface of the standard flange and a facing surface of the threaded flange. Preferably, the threaded flange includes an annular slot or groove that receives the o-ring, and the facing surface of the standard flange is sized to be received within the annular groove where the o-ring resides. As the lock nut group is advanced towards the threaded flange in the locking direction rotation, the o-ring is compressed thereby creating a leakproof seal.
[0020] The coupling of the present invention also maintains outstanding electrical conductivity through the entire fitting assembly to ensure that there is minimal or no static buildup across the connection between the conduit members. The use of a single o-ring member which is bypassed by metal to metal contact of numerous components of the coupling assembly ensures that there is minimal isolation of parts in the first and second conduit members. Additionally, electrical conductivity can be further enhanced by coating various elements of the coupling assembly with conductive coatings. Conductive coatings that may be used include electroless nickel or nickel Teflon coatings. One or more of the parts or elements, as necessary, can be provided with the conductive coatings. Accordingly, the coupling assembly of the present invention requires no bonding springs within the conduit members, nor does the coupling require any electrical jumpers that are normally mounted to the coupling assembly in order to ensure electrical continuity.
[0021] Types of materials that can be used with the various components of the coupling assembly of the present invention include, but are not limited to, titanium based alloys, aluminum alloys, or even stainless steel alloys. Of course, the most lightweight and high strength alloys are of particular utility with regard to aircraft applications.
[0022] Also in accordance with another aspect of the present invention, a method is provided for interconnecting a pair of confronting ends of conduit members. The method is particularly useful with respect to conduits used to convey fuel and hydraulic fluids. The method comprises providing a pair of confronting ends of conduit members that must be joined in a rigid connection, configuring the ends of the conduit members to include a standard flange on one end and a threaded flange on the other end, providing a lock nut group for joining the standard flange to the threaded flange, and ensuring a locking arrangement between the flanges by a locking arrangement of the lock nut group with respect to the threaded flange.
[0023] Additional advantages and features of the present invention will become apparent from the detailed description which follows, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is an elevation or side view illustrating the primary components of the coupling of the present invention aligned along a longitudinal axis;
[0025] FIG. 2 is an exploded perspective view of the components shown in FIG. 1 aligned along the longitudinal axis;
[0026] FIG. 3 is an exploded perspective view of the lock nut group of the present invention;
[0027] FIG. 4 is an enlarged vertical section of an assembled lock nut group in accordance with the construction of FIG. 3 ;
[0028] FIG. 5 is an enlarged perspective view of a threaded flange;
[0029] FIG. 6 is a greatly enlarged vertical section of the threaded flange of FIG. 5 ;
[0030] FIG. 7 is an enlarged perspective view of a standard flange;
[0031] FIG. 8 is a greatly enlarged vertical section of the standard flange of FIG. 7 ;
[0032] FIG. 9 is a greatly enlarged vertical section of the coupling assembly of the present invention joining confronting ends of first and second conduit members;
[0033] FIG. 10 is a greatly enlarged vertical section of the coupling assembly of the present invention showing the coupling assembly in an unlocked position; and
[0034] FIG. 11 is an elevation or side view of the coupling assembly showing the coupling assembly in a locked position.
DETAILED DESCRIPTION
[0035] FIGS. 1 and 2 illustrate the coupling assembly 10 of the present invention for rigidly connecting confronting ends of two conduit members.
[0036] Basic or primary components of the coupling assembly include a threaded flange or first coupling member 14 , a lock nut group or second coupling member 12 , a standard flange 16 , an o-ring 18 positioned between a facing surface of the standard flange and a facing surface of the threaded flange, and a rigid connecting means or flat washer 20 that is positioned at the interface between the lock nut group and the standard flange.
[0037] Assembly of the coupling assembly includes placement of the flat washer 20 within the lock nut group and alignment with the opening of the lock nut group, and positioning the lock nut group over the standard flange so that when assembled, the flat washer 20 is trapped between an exterior shoulder 17 of the standard flange and an interior shoulder 45 of the nut body 44 , as further discussed below.
[0038] The o-ring 18 is received within an annular groove or recess 76 ( FIG. 6 ) formed on facing surface 74 of the threaded flange. The facing surface 82 of the standard flange ( FIG. 7 ) compresses the o-ring 18 as the lock nut group is drawn toward the threaded flange by rotating the lock nut group in the locking direction by engagement of interior threads 56 of the lock nut group with exterior threads 72 of the threaded flange. In the locked position, the pair of slots or reliefs 40 formed on the peripheral edge of the lock nut group 12 align with and engage the projections or tabs 66 formed on the rim or peripheral edge of the threaded flange.
[0039] Now referring to FIGS. 3 and 4 , the lock nut group 12 is illustrated. The lock ring 30 is characterized by an outer rim 32 that may be roughened or knurled, a rim extension 33 that extends axially away from the outer rim 32 , and one or more notches or reliefs 40 that engage corresponding projections or tabs 66 on the threaded flange when the coupling is in the locked position. Additionally, the interior surface of the lock ring includes one or more keys or projections 38 that align with corresponding key ways or slots 48 formed on the outer rim 46 of the lock nut 44 . The nut body is inserted coaxially within the lock ring so that the keys and key ways are aligned. The key ways 48 allow relative axial displacement of the lock nut with respect to the nut body, but prevent relative rotational movement between the lock ring and nut body. Lock ring 30 is attached to nut body 44 as by a split retainer 60 that is received within an annular slot or groove 34 formed on the interior surface of the lock ring 30 . The split retainer 60 is reduced in circumference by first closing the ends 61 towards one another, placing the split retainer 60 within the groove 34 , and then releasing the ends 61 whereby the split retainer returns to its undeformed state with an enlarged circumference and thereby being held within the groove 34 .
[0040] The structure of the nut body 44 is further characterized as including an interior shoulder 50 , an exterior shoulder 52 , and an axial extension 54 interconnecting the interior and exterior shoulders. The inner surface of the nut group includes threads 56 which are threaded over the exterior threads 72 of the threaded flange, as further discussed below.
[0041] A biasing member, shown in the preferred embodiment as a wave spring 58 , is provided for biased relative axial displacement between the lock ring and nut body. Prior to inserting the nut body in the lock ring, the wave spring is positioned over the extension 54 . Referring to FIG. 4 , when the lock nut group is assembled, the spring 58 is maintained in the gap or space between the lock ring and the nut body. This gap or space is delimited annularly by the extension 54 and the interior surface 36 of the lock ring. This gap or space is delimited axially by the split retainer 60 and by the interior shoulder 50 . Thus in the arrangement shown in FIG. 4 , biased axial movement is allowed between the lock ring and nut body to the extent that the spring 58 can be compressed and decompressed in the gap or space, yet relative rotational movement of the lock ring and nut body are prevented by the key and key way arrangement.
[0042] Now referring to FIGS. 5 and 6 , the particular configuration of the threaded flange is illustrated. The threaded flange 14 is characterized by a protruding rim 64 , and one or more projection tabs 66 which are spaced from one another in the same spacing as the notches 40 . In the preferred embodiment as shown, a pair of tabs and notches are present. The tabs and notches are spaced from one another approximately 180 degrees. A sleeve 68 extends axially from the rim 64 in one direction, and external threads 72 extend from the rim 64 in the opposite axial direction. The interior surface of the sleeve 68 includes a plurality of swaging grooves 70 , and the first conduit 22 preferably attached to the threaded flange as by a swaging operation wherein the free end of the conduit member is swaged with respect to the interior surface of the sleeve 68 . The threaded flange 14 further includes a facing surface 74 , and an annular groove or slot 76 that is formed on the face 74 . The annular groove 76 is sized to receive the o-ring 18 .
[0043] Now referring to FIGS. 7 and 8 , the standard flange 16 is illustrated. The standard flange 16 includes a rib 80 , a contact face or surface 82 , and a sleeve 84 . The interior surface of the standard flange also preferably includes swaging grooves 86 wherein the free end of the second conduit member 24 is preferably swaged with respect to the interior surface of the sleeve 84 .
[0044] Now referring to FIGS. 9 and 10 , the coupling assembly is illustrated when assembled. FIG. 9 more specifically illustrates the lock nut group threaded over the threads of the threaded flange, but the lock ring has not yet snap fit into the locked position, thus, some gap g exists between the facing surface of the rim extension 33 and the tabs 66 . Accordingly, the spring is still compressed in the gap or space between the nut body and the lock ring. As also shown, the flat washer 20 is trapped between the exterior shoulder 17 of the standard flange and the interior shoulder 45 of the nut body. The o-ring 18 is positioned in the annular groove 76 of the threaded flange, and the facing surface 82 of the standard flange fits in the annular groove and compresses the o-ring thereby creating a leak proof seal. Referring to FIG. 10 , the lock ring has been displaced by the force from the spring 58 so that the notches 40 are engaged with the respective tabs 66 . FIG. 11 also illustrates the coupling in the locked position. The exterior threads 72 on the threaded flange and the interior threads 56 on the nut body are clocked so that a desired number of rotations of the lock nut group allows the notches 40 to snap fit in engagement with the tabs 66 . Because of the biased arrangement between the lock ring and nut body, as the lock nut group is screwed over the threads of the threaded flange, there will be a distinct clicking sound once the notches 40 engage the tabs 66 . This audible indication allows the user to know that the lock nut group has now been placed in a locking relationship. In addition to this audible sound, an indicator stripe (not shown) in the form of a florescent colored annular marking may be placed around the portion of the peripheral surface of the rim 64 that becomes covered by the lock ring when the coupling is placed in the locked position. Thus when the indicator stripe or marking disappears, this indicates to a user that the coupling is locked and ready for operation. As can also be seen in FIGS. 9 and 10 , the rigid nature of the attachment between the conduit members is further enhanced by the close tolerance fit between the peripheral outer edge or surface 81 of the standard flange with respect to the inner circumferential facing edge 73 .
[0045] It is also apparent from FIGS. 9 and 10 that there is substantial continuous contact between the components of the coupling assembly which bypass the o-ring thereby providing an electrically conductive path that eliminates electrostatic potential between the conduit members. The path is defined by contact of the standard flange with the flat washer 20 , contact of the flat washer with the lock nut group, and contact of the lock nut group with the standard flange by the threaded arrangement. Although the o-ring 18 provides a seal between the standard flange and the threaded flange, metal to metal contact is still achieved across this sealed interface by the electrical conductive path, thereby eliminating the need for an externally mounted bonding strap that is typically used to maintain electrical continuity.
[0046] When it is desired to unlock the coupling assembly, the lock ring is pulled axially away from the rim 64 of the threaded flange by grasping the outer rim 32 , and then the lock nut group is rotated in an unlocking direction thereby unscrewing the lock nut group from the threaded flange.
[0047] The coupling assembly of the present invention provides a reliable and structurally stable connection. The connection is rigid thereby eliminating the need for support hangars at or adjacent the coupling. The coupling is easily installed and requires no bonding strap. The coupling assembly is easily maintained because it can be disassembled down to a component level for inspection and for component replacement as necessary.
[0048] The present invention has been described with respect to a preferred embodiment; however, other changes and modifications can be made to the invention within the scope of the claims appended hereto. | A coupling assembly is provided for releasably interconnecting confronting ends of conduit members. The coupling assembly creates a self-locking, and self-bonding connection wherein locking and unlocking is achieved by a predetermined amount of rotation of a lock nut group with respect to a stationary threaded flange. The overall construction of the coupling assembly creates the rigid connection between the conduit members, yet adequate sealing between the conduit members is provided by a single sealing member. | 5 |
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional of U.S. patent application Ser. No. 13/882,719, filed Jul. 29, 2013, now U.S. Pat. No. 8,932,562, which is a national stage filing under 35 U.S.C. §371 of PCT/US2011/059298, which claims the priority benefit of U.S. provisional application Ser. No. 61/410,748 filed on Nov. 5, 2010, and 61/464,806 filed on Mar. 8, 2011, the contents of each of which applications are incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
Anxiety is a sustained state of heightened apprehension in the absence of immediate threat, which in disease states becomes severely debilitating. Anxiety disorders represent the most common of the psychiatric diseases (with 28% lifetime prevalence), and have been linked to the etiology of major depression and substance abuse. While the amygdala, a brain region important for emotional processing, has long been hypothesized to play a role in anxiety, the neural mechanisms which control and mediate anxiety have yet to be identified. Despite the high prevalence and severity of anxiety disorders, the corresponding neural circuit substrates are poorly understood, impeding the development of safe and effective treatments. Available treatments tend to be inconsistently effective or, in the case of benzodiazepines, addictive and linked to significant side effects including sedation and respiratory suppression that can cause cognitive impairment and death. A deeper understanding of anxiety control mechanisms in the mammalian brain is necessary to develop more efficient treatments that have fewer side-effects. Of particular interest and novelty would be the possibility of recruiting native pathways for anxiolysis.
SUMMARY OF THE INVENTION
Provided herein is an animal comprising a light-responsive opsin expressed in glutamatergic pyramidal neurons of the basolateral amygdala (BLA), wherein the selective illumination of the opsin in the BLA-CeL induces anxiety or alleviates anxiety of the animal.
Provided herein is an animal comprising a light-responsive opsin expressed in glutamatergic pyramidal neurons of the BLA, wherein the opsin is an opsin which induces hyperpolarization by light, and wherein the selective illumination of the opsin in the BLA-CeL induces anxiety of the animal. In some embodiments, the opsin is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3. In some embodiments, the animal further comprises a second light-responsive opsin expressed in glutamatergic pyramidal neurons of the BLA, wherein the second opsin is an opsin that induces depolarization by light, and wherein the selective illumination of the second opsin in the BLA-CeL reduces anxiety of the animal. In some embodiments, the second opsin is ChR2, VChR1, or DChR. In some embodiments, the second opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the second opsin comprises the amino acid sequence of SEQ ID NO:6 or 7.
Provided herein is an animal comprising a light-responsive opsin expressed in the glutamatergic pyramidal neurons of the BLA, wherein the opsin is an opsin that induces depolarization by light, and wherein the selective illumination of the opsin in the BLA-CeL reduces anxiety of the animal. In some embodiments, the opsin is ChR2, VChR1, or DChR. In some embodiments, the opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the opsin comprises the amino acid sequence of SEQ ID NO:6 or 7.
Also provided herein is a vector for delivering a nucleic acid to glutamatergic pyramidal neurons of the BLA in an individual, wherein the vector comprises the nucleic acid encoding a light-responsive opsin and the nucleic acid is operably linked to a promoter that controls the specific expression of the opsin in the glutamatergic pyramidal neurons. In some embodiments, the promoter is a CaMKIIα promoter. In some embodiments, the vector is an AAV vector. In some embodiments, the opsin is an opsin that induces depolarization by light, and wherein selective illumination of the opsin in the BLA-CeL alleviates anxiety. In some embodiments, the opsin that induces depolarization by light is ChR2, VChR1, or DChR. In some embodiments, the opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the opsin comprises the amino acid sequence of SEQ ID NO:6 or 7. In some embodiments, the opsin is an opsin that induces hyperpolarization by light, and wherein selective illumination of the opsin in the BLA-CeL and induces anxiety. In some embodiments, the opsin that induces hyperpolarization by light is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3. In some embodiments, the individual is a mouse or a rat. In some embodiments, the individual is a human.
Also provided here is a method of delivering a nucleic acid to glutamatergic pyramidal neurons of the BLA in an individual, comprising administering to the individual an effective amount of a vector comprising a nucleic acid encoding a light-responsive opsin and the nucleic acid is operably linked to a promoter that controls the specific expression of the opsin in the glutamatergic pyramidal neurons. In some embodiments, the promoter is a CaMKIIα promoter. In some embodiments, the vector is an AAV vector. In some embodiments, the opsin is an opsin that induces depolarization by light, and wherein selective illumination of the opsin in the BLA-CeL alleviates anxiety. In some embodiments, the opsin that induces depolarization by light is ChR2, VChR1, or DChR. In some embodiments, the opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the opsin comprises the amino acid sequence of SEQ ID NO:6 or 7. In some embodiments, the opsin is an opsin that induces hyperpolarization by light, and wherein selective illumination of the opsin in the BLA-CeL and induces anxiety. In some embodiments, the opsin that induces hyperpolarization by light is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3. In some embodiments, the individual is a mouse or a rat. In some embodiments, the individual is a human.
Also provided herein is a coronal brain tissue slice comprising BLA, CeL, and CeM, wherein a light-responsive opsin is expressed in the glutamatergic pyramidal neurons of the BLA. In some embodiments, the opsin is an opsin that induces depolarization by light. In some embodiments, the opsin that induces depolarization by light is ChR2, VChR1, or DChR. In some embodiments, the opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the opsin comprises the amino acid sequence of SEQ ID NO:6 or 7. In some embodiments, the opsin is an opsin that induces hyperpolarization by light. In some embodiments, the opsin that induces hyperpolarization by light is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3. In some embodiments, the tissue is a mouse or a rat tissue.
Also provided herein is a method for screening for a compound that alleviates anxiety, comprising (a) administering a compound to an animal having anxiety induced by selectively illumination of an opsin expressed in the glutamatergic pyramidal neurons of the BLA, wherein the animal comprises a light-responsive opsin expressed in the glutamatergic pyramidal neurons of the BLA, wherein the opsin is an opsin that induces hyperpolarization by light; and (b) determining the anxiety level of the animal, wherein a reduction of the anxiety level indicates that the compound may be effective in treating anxiety. In some embodiments, the opsin is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3.
Also provided herein is a method for alleviating anxiety in an individual, comprising: (a) administering to the individual an effective amount of a vector comprising a nucleic acid encoding a light-responsive opsin and the nucleic acid is operably linked to a promoter that controls the specific expression of the opsin in the glutamatergic pyramidal neurons of the BLA, wherein the opsin is expressed in the glutamatergic pyramidal neurons of the BLA, wherein the opsin is an opsin that induces depolarization by light; and (b) selectively illuminating the opsin in the glutamatergic pyramidal neurons in the BLA-CeL to alleviate anxiety. In some embodiments, the promoter is a CaMKIIα promoter. In some embodiments, the vector is an AAV vector. In some embodiments, the opsin is ChR2, VChR1, or DChR. In some embodiments, the opsin is a C1V1 chimeric protein comprising the amino acid sequence of SEQ ID NO:8, 9, 10, or 11. In some embodiments, the opsin comprises the amino acid sequence of SEQ ID NO:6 or 7.
Also provided herein is a method for inducing anxiety in an individual, comprising: (a) administering to the individual an effective amount of a vector comprising a nucleic acid encoding an opsin and the nucleic acid is operably linked to a promoter that controls the specific expression of the opsin in the glutamatergic pyramidal neurons of the BLA, wherein the opsin is expressed in the glutamatergic pyramidal neurons, wherein the opsin is an opsin that induces hyperpolarization by light; and (b) selectively illuminating the opsin in the glutamatergic pyramidal neurons in the BLA-CeL to induce anxiety. In some embodiments, the promoter is a CaMKIIα promoter. In some embodiments, the vector is an AAV vector. In some embodiments, the opsin is NpHR, BR, AR, or GtR3. In some embodiments, the NpHR comprises the amino acid sequence of SEQ ID NO:1, 2, or 3.
It is to be understood that one, some, or all of the properties of the various embodiments described herein may be combined to form other embodiments of the present invention. These and other aspects of the invention will become apparent to one of skill in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Various example embodiments may be more completely understood in consideration of the following description and the accompanying drawings, in which:
FIG. 1 shows a system for providing optogenetic targeting of specific projections of the brain, consistent with an embodiment of the present disclosure; and
FIG. 2 shows a flow diagram for use of an anxiety-based circuit model, consistent with an embodiment of the present disclosure.
FIG. 3 shows that projection-specific excitation of BLA terminals in the CeA induced acute reversible anxiolysis. a) All mice were singly-housed in a high-stress environment for at least 1 week prior to behavioral manipulations and receive 5-ms light pulses at 20 Hz for all light on conditions. Mice in the ChR2:BLA-CeA group received viral transduction of ChR2 in BLA neurons under the CaMKII promoter and were implanted with a beveled cannula shielding light away from BLA somata to allow selective illumination of BLA terminals in the CeA, while control groups either received a virus including fluorophore only (EYFP:BLA-CeA group) or a light fiber directed to illuminate BLA somata (ChR2:BLA Somata group). (b-c) Mice in the ChR2:BLA-CeA group (n=8) received selective illumination of BLA terminals in the CeA during the light on epoch during the elevated plus maze, as seen in this ChR2:BLA-CeA representative path (b), which induced a 5-fold increase in open arm time during the light on epoch relative to the light off epochs and EYFP:BLA-CeA (n=9) and ChR2:BLA Somata (n=7) controls (c), as well as a significant increase in the probability of entering the open arm (see inset). (d-f) Mice in the ChR2:BLA-CeA group also showed an increase in the time spent in the center of the open field chamber, as seen in this representative trace (d), during light on epochs relative to light off epochs and EYFP:BLA-CeA and ChR2:BLA Somata controls (e), but did not show a significant change in locomotor activity during light on epochs (f). g) Confocal image of a coronal slice showing the CeA and BLA regions from a mouse in the ChR2:BLA-CeA group wherein 125 μm×125 μm squares indicate regions used for quantification. h) Expanded regions are arranged in rows by group and in columns by brain region. (i-k) Percent of EYFP-positive and c-fos-positive neurons of all DAPI-identified cells for all groups, by region. Numbers of counted per group and region are indicated in legends. None of the regions examined showed detectable differences in the proportion of EYFP-positive cells among groups. i) Proportion of BLA neurons that were EYFP-positive or c-fos-positive. The ChR2:BLA Somata group had a significantly higher proportion of c-fos-positive BLA neurons (F 2,9 =10.12, p<0.01) relative to ChR2:BLA-CeA (p<0.01) or EYFP:BLA-CeA (p<0.05) groups. j) The ChR2:BLA-CeA group had a significantly higher proportion of c-fos-positive cells in the CeL relative to the EYFP:BLA-CeA group (p<0.05), but not the ChR2:BLA Somata group. k) Summary data for CeM neurons show no detectable differences among groups.
FIG. 4 shows projection-specific excitation of BLA terminals in the CeA activates CeL neurons and elicits feed-forward inhibition of CeM neurons. a) Live two-photon images of representative light-responsive BLA, CeL and CeM cells all imaged from the same slice, overlaid on a brightfield image. (b-f) Schematics of the recording and illumination sites for the associated representative current-clamp traces (V m =˜70 mV). b) Representative trace from a BLA pyramidal neuron expressing ChR2, all BLA neurons expressing ChR2 in the BLA spiked for every 5 ms pulse (n=4). c) Representative trace from a CeL neuron in the terminal field of BLA projection neurons, showing both sub-threshold and supra-threshold excitatory responses to light-stimulation (n=16). Inset left, population summary of mean probability of spiking for each pulse in a 40-pulse train at 20 Hz, dotted lines indicate SEM. Inset right, frequency histogram showing individual cell spiking fidelity for 5 ms light pulses delivered at 20 Hz, y-axis is the number of cells per each 5% bin. d) Six sweeps from a CeM neuron spiking in response to a current step (˜60 pA; indicated in black) and inhibition of spiking upon 20 Hz illumination of BLA terminals in the CeL. Inset, spike frequency was significantly reduced during light stimulation of CeL neurons (n=4). (e-f) Upon broad illumination of the CeM, voltage-clamp summaries show that the latency of EPSCs is significantly shorter than the latency of IPSCs, while there was a non-significant difference in the amplitude of EPSCs and IPSCs (n=11; *p=0.04, see insets). The same CeM neurons (n=7) showed either net excitation when receiving illumination of the CeM (e) or net inhibition upon selective illumination of the CeL (f).
FIG. 5 shows light-induced anxiolytic effects were attributable to activation of BLA-CeL synapses alone. (a-b) 2-photon z-stack images of 18 dye-filled BLA neurons were reconstructed, and their projections to the CeL and CeM are summarized in (a), with their images shown in (b) wherein red indicates projections to CeL, blue indicates projections to CeM and purple indicates projections to both CeL and CeM. c) Schematic of the recording site and the light spot positions, as whole-cell recordings were performed at each location of the light spot, which was moved in 100 um-steps away from the cell soma both over a visualized axon and in a direction that was not over an axon. d) Normalized current-clamp summary of spike fidelity to a 20 Hz train delivered at various distances from the soma, showing that at ˜300 um away from the cell soma, illumination of an axon terminal results in low (<5%) spike fidelity. e) Normalized voltage-clamp summary of depolarizing current seen at the cell soma upon illumination per distance from cell soma. (f-i) Representative current-clamp traces upon illumination with a ˜150 um-diameter light spot over various locations within each slice preparation (n=7). Illumination of the cell soma elicits high-fidelity spiking (f). Illumination of BLA terminals in CeL elicits strong sub- and supra-threshold excitatory responses in the postsynaptic CeL neuron (g), but does not elicit reliable antidromic spiking in the BLA neuron itself (h), and light delivered off axon is shown for comparison as a control for light scattering (i). (k-j) A separate group of ChR2:BLA-CeL mice (n=8) were each run twice on the elevated plus maze and the open field test, one session preceded with intra-CeA infusions of saline (red) and the other session with the glutamate receptor antagonists NBQX and AP5 (purple), counterbalanced for order. k) Glutamate receptor blockade in the CeA attenuated light-induced increases in both time spent in open arms as well as the probability of open arm entry (inset) on the elevated plus maze without impairing performance during light off epochs. j) Local glutamate receptor antagonism significantly attenuated light-induced increases in center time on the open field test, inset shows pooled summary.
FIG. 6 shows that selective inhibition of BLA terminals in the CeA induced an acute and reversible increase in anxiety. a) All mice were group-housed in a low-stress environment and received bilateral constant 591 nm light during light on epochs. Mice in the eNpHR3.0:BLA-CeA group (n=9) received bilateral viral transduction of eNpHR3.0 in BLA neurons under the CaMKII promoter and were implanted with a beveled cannula shielding light away from BLA somata to allow selective illumination of BLA terminals in the CeA, while control groups either received bilateral virus transduction of a fluorophore only (EYFP:BLA-CeA bil group; n=8) or a light fiber directed to illuminate BLA somata (eNpHR3.0:BLA Somata group; n=6). b) Confocal image of the BLA and CeA of a mouse treated with eNpHR3.0. (c-e) In the same animals used in anxiety assays below, a significantly higher proportion of neurons in the CeM (e) from the eNpHR3.0 group expressed c-fos relative to the EYFP group (*p<0.05). f) Representative path of a mouse in the eNpHR3.0:BLA-CeA group, showing a decrease in open arm exploration on the elevated plus maze during epochs of selective illumination of BLA terminals in the CeA. g) eNpHR3.0 mice showed a reduction in the time spent in open arms and probability of open arm entry (inset) during light stimulation, relative to controls. h) Representative path of a mouse from the eNpHR3.0:BLA-CeA group during pooled light off and on epochs in the open field test. i) Significant reduction in center time in the open field chamber for the eNpHR3.0:BLA-CeA group during light on, but not light off, epochs as compared to controls, inset shows pooled data summary. (j−1) Selective illumination of eNpHR3.0-expressing BLA terminals is sufficient to reduce spontaneous vesicle release in the presence of carbachol. Representative trace of a CeL neuron (j) from an acute slice preparation in which BLA neurons expressed eNpHR 3.0, shows that when BLA terminals ˜300 μm away from the BLA soma are illuminated, there is a reduction in the amplitude (k) and frequency (1) of sEPSCs seen at the postsynaptic CeL neuron. Cumulative distribution frequency of the amplitude (k) and frequency (l) of sEPSCs recorded at CeL neurons (n=5) upon various lengths of illumination 5-60 s, insets show respective mean+SEM in the epochs of matched duration before, during and after illumination (**p<0.01; ***p<0.001). (m-p) Selective illumination of BLA terminals expressing eNpHR 3.0 suppresses vesicle release evoked by electrical stimulation in the BLA. m) Schematic indicating the locations of the stimulating electrode, the recording electrode and the ˜150 μm diameter light spot. n) Representative traces of EPSCs in a CeL neuron before (Off 1 ), during (On) and after (Off 2 ) selective illumination of BLA terminals expressing eNpHR3.0. Normalized EPSC amplitude summary data (o) and individual cell data (p) from slice preparations containing BLA neurons expressing eNpHR 3.0 (n=7) and non-transduced controls (n=5) show that selectively illuminating BLA terminals in the CeL significantly (*p=0.006) reduces the amplitude of electrically-evoked EPSCs in postsynaptic CeL neurons.
FIG. 7 is a diagram showing the histologically verified placements of mice treated with 473 nm light. Unilateral placements of the virus injection needle (circle) and the tip of beveled cannula (x) are indicated, counter-balanced for hemisphere. Colors indicate treatment group, see legend. Coronal sections containing the BLA and the CeA are shown here, numbers indicate the anteroposterior coordinates from bregma (Aravanis et al., J Neural Eng, 4:S143-156, 2007).
FIG. 8 shows the beveled cannula and illumination profile design. a) Light cone from bare fiber emitting 473 nm light over cuvette filled with fluorescein in water. The angle of the light cone is approximately 12 degrees. b) Light cone from the same fiber and light ensheathed in a beveled cannula. The beveled cannula blocks light delivery to one side, without detectably altering perpendicular light penetrance. c) Diagram of light delivery via the optical fiber with the beveled cannula over CeA. d) Chart indicating estimated light power density seen at various distances from the fiber tip in mouse brain tissue when the light power density seen at the fiber tip was 7 mW (˜99 mW/mm 2 ) Inset, cartoon indicating the configuration. Optical fiber is perpendicular and aimed at the center of the power meter, through a block of mouse brain tissue. e) Table showing light power (mW) as measured by a standard power meter and the estimated light power density (mW/mm 2 ) seen at the tip, at the CeL (˜0.5-0.7 mm depth in brain tissue) and at the CeM (˜1.1 mm depth in brain tissue).
FIG. 9 demonstrates that the beveled cannula prevented light delivery to BLA and BLA spiking at light powers used for behavioral assays. a) Schematic indicating the configuration of light delivery by optical fiber to the CeA and recording electrode (red) in the BLA. b) Scatterplot summary of recordings in the BLA with various light powers delivered to the CeA with and without the beveled cannula (n=4 sites). For each site, repeated alternations of recordings were made with and without the beveled cannula. The x-axis shows both the light power density at the fiber tip (black) and the estimated light power density at the CeL (grey). The blue vertical or shaded region indicates the range of light power densities used for behavioral assays (˜7 mW; ˜99 mW/mm 2 at the tip of the fiber). Reliable responses from BLA neurons were not observed in this light power density range. c) Representative traces of BLA recordings with 20 Hz 5 ms pulse light stimulation at 7 mW (˜99 mW/mm 2 at fiber tip; ˜5.9 mW/mm 2 at CeL) at the same recording site in the CeA. d) Population spike waveforms in response to single pulses of light reveal substantial light restriction even at high 12 mV power (˜170 mW/mm 2 at the tip of the fiber; ˜10.1 mW/mm 2 at CeL).
FIG. 10 demonstrates that viral transduction excluded intercalated cell clusters. a) Schematic of the intercalated cells displayed in subsequent confocal images. (b-d) Representative images of intercalated cells from mice that received EYFP b), eNpHR 3.0 c) and ChR2 d) injections into the BLA that were used for behavioral manipulations. Viral expression was not observed in intercalated cell clusters. (e-f) There were very low (<2%) levels of YFP expression in intercalated cell clusters for all 6 groups used in behavioral assays. There were no statistically significant differences among groups in c-fos expression.
FIG. 11 shows that unilateral intra-CeA administration of glutamate antagonists did not alter locomotor activity. Administration of NBQX and AP5 prior to the open field test did not impair locomotor activity (as measured by mean velocity) relative to saline infusion (F 1,77 =2.34, p=0.1239).
FIG. 12 demonstrates that bath application of glutamate antagonists blocked optically-evoked synaptic transmission. 4-6 weeks following intra-BLA infusions of AAV5-CamKII-ChR2-EYFP into the BLA of wild-type mice, we examined the ability of the glutamate receptor antagonists NBQX and AP5 to block glutamatergic transmission. a) Representative current-clamp (top) and voltage-clamp (bottom) traces of a representative CeL neuron upon a 20 Hz train of 473 nm light illumination of BLA terminals expressing ChR2. b) The same cell's responses following bath application of NBQX and AP5 show abolished spiking and EPSCs. c) Population summary (n=5) of the depolarizing current seen before and after bath application of NBQX and AP5, normalized to the pre-drug response.
FIG. 13 is a diagram depicting the histologically verified placements of mice treated with 594 nm light. Bilateral placements of virus injection needle (circle) and tip of beveled cannula (x) are indicated. Colors indicate treatment group, see legend. Coronal sections containing BLA and CeA are shown; numbers indicate AP coordinates from bregma (Aravanis et el., J Neural Eng, 4:S143-156, 2007).
FIG. 14 shows that light stimulation parameters used in the eNpHR 3.0 terminal inhibition experiments does not block spiking at the cell soma. (a-c) Schematics of the light spot location and recording sites alongside corresponding representative traces upon a current step lasting the duration of the spike train, paired with yellow light illumination at each location during the middle epoch (indicated by yellow horizontal bar). a) Representative current-clamp trace from a BLA neuron expressing eNpHR 3.0 upon direct illumination shows potent inhibition of spiking during illumination of cell soma. b) Representative current-clamp trace from a BLA neuron expressing eNpHR 3.0 when a ˜125 μm diameter light spot is presented ˜300 μm away from the cell soma without illuminating an axon. c) Representative current-clamp trace from a BLA neuron expressing eNpHR 3.0 when a ˜125 μm diameter light spot is presented ˜300 μm away from the cell soma when illuminating an axon. d) While direct illumination of the cell soma induced complete inhibition of spiking that was significant from all other conditions (F 3,9 =81.50, p<0.0001; n=3 or more per condition), there was no significant difference among the distal illumination ˜300 μm away from the soma of BLA neurons expressing eNpHR 3.0 conditions and the no light condition (F 2,7 =0.79, p=0.49), indicating that distal illumination did not significantly inhibit spiking at the cell soma. e) Schematic indicating light spot locations relative to recording site, regarding the population summary shown to the right. Population summary shows the normalized hyperpolarizing current recorded from the cell soma per distance of light spot from cell soma, both on and off axon collaterals (n=5).
FIG. 15 demonstrates that selective illumination of BLA terminals induced vesicle release onto CeL neurons without reliably eliciting antidromic action potentials. Schematics and descriptions refer to the traces below, and trace color indicates cell type. Light illumination patterns are identical for both series of traces. Left column, CeL traces for three overlaid sweeps of a 40-pulse light train per cell (n=8). Here, both time-locked EPSCs indicate vesicle release from the presynaptic ChR2-expressing BLA terminal, and for all postsynaptic CeL cells, there were excitatory responses to 100% of light pulses. Right column, BLA traces for three overlaid 40-pulse sweeps per cell (n=9), with the mean number of light pulses delivered at the axon terminal resulting in a supra-threshold antidromic action potential (5.4%±2%, mean±SEM).
FIG. 16 is a graph demonstrating that light stimulation did not alter locomotor activity in eNpHR 3.0 and control groups. There were no detectable differences in locomotor activity among groups nor light epochs (F 1,20 =0.023, p=0.3892; F 1,100 =3.08, p=0.086).
DETAILED DESCRIPTION
The present disclosure relates to control over nervous system disorders, such as disorders associated with anxiety and anxiety symptoms, as described herein. While the present disclosure is not necessarily limited in these contexts, various aspects of the invention may be appreciated through a discussion of examples using these and other contexts.
Various embodiments of the present disclosure relate to an optogenetic system or method that correlates temporal control over a neural circuit with measurable metrics. For instance, various metrics or symptoms might be associated with a neurological disorder exhibiting various symptoms of anxiety. The optogenetic system targets a neural circuit within a patient for selective control thereof. The optogenetic system involves monitoring the patient for the metrics or symptoms associated with the neurological disorder. In this manner, the optogenetic system can provide detailed information about the neural circuit, its function and/or the neurological disorder.
Consistent with the embodiments discussed herein, particular embodiments relate to studying and probing disorders. Other embodiments relate to the identification and/or study of phenotypes and endophenotypes. Still other embodiments relate to the identification of treatment targets.
Aspects of the present disclosure are directed to using an artificially-induced anxiety state for the study of anxiety in otherwise healthy animals. This can be particularly useful for monitoring symptoms and aspects that are poorly understood and otherwise difficult to accurately model in living animals. For instance, it can be difficult to test and/or study anxiety states due to the lack of available animals exhibiting the anxiety state. Moreover, certain embodiments allow for reversible anxiety states, which can be particularly useful in establishing baseline/control points for testing and/or for testing the effects of a treatment on the same animal when exhibiting the anxiety state and when not exhibiting the anxiety state. The reversible anxiety states of certain embodiments can also allow for a reset to baseline between testing the effects of different treatments on the same animal.
Certain aspects of the present disclosure are directed to a method related to control over anxiety and/or anxiety symptoms in a living animal. In certain more specific embodiments, the monitoring of the symptoms also includes assessing the efficacy of the stimulus in mitigating the symptoms of anxiety. Various other methods and applications exist, some of which are discussed in more detail herein.
Light-responsive opsins that may be used in the present invention includes opsins that induce hyperpolarization in neurons by light and opsins that induce depolarization in neurons by light. Examples of opsins are shown in Tables 1 and 2 below.
Table 1 shows identified opsins for inhibition of cellular activity across the visible spectrum:
TABLE 1 Fast optogenetics: inhibition across the visible spectrum Biological Wavelength Opsin Type Origin Sensitivity Defined action NpHR Natronomonas 589 nm max Inhibition pharaonis (hyperpolarization) BR Halobacterium 570 nm max Inhibition helobium (hyperpolarization) AR Acetabulaira 518 nm max Inhibition acetabulum (hyperpolarization) GtR3 Guillardia 472 nm max Inhibition theta (hyperpolarization) Mac Leptosphaeria 470-500 nm max Inhibition maculans (hyperpolarization) NpHr3.0 Natronomonas 680 nm utility Inhibition pharaonis 589 nm max (hyperpolarization) NpHR3.1 Natronomonas 680 nm utility Inhibition pharaonis 589 nm max (hyperpolarization)
Table 2 shows identified opsins for excitation and modulation across the visible spectrum:
TABLE 2 Fast optogenetics: excitation and modulation across the visible spectrum Wavelength Opsin Type Biological Origin Sensitivity Defined action VChR1 Volvox carteri 589 nm utility Excitation 535nm max (depolarization) DChR Dunaliella sauna 500 nm max Excitation (depolarization) ChR2 Chlamydomonas 470 nm max Excitation reinhardtii 380-405 nm utility (depolarization) ChETA Chlamydomonas 470 nm max Excitation reinhardtii 380-405 nm utility (depolarization) SFO Chlamydomonas 470 nm max Excitation reinhardtii 530 nm max (depolarization) Inactivation SSFO Chlamydomonas 445 nm max Step-like activation reinhardtii 590 nm; (depolarization) 390-400 nm Inactivation C1V1 Volvox carteri and 542 nm max Excitation Chlamydomonas (depolarization) reinhardtii C1V1 E122 Volvox carteri and 546 nm max Excitation Chlamydomonas (depolarization) reinhardtii C1V1 E162 Volvox carteri and 542 nm max Excitation Chlamydomonas (depolarization) reinhardtii C1V1 E122/ Volvox carteri and 546 nm max Excitation E162 Chlamydomonas (depolarization) reinhardtii
Table 2 (Continued):
As used herein, a light-responsive opsin (such as NpHR, BR, AR, GtR3, Mac, ChR2, VChR1, DChR, and ChETA) includes naturally occurring protein and functional variants, fragments, fusion proteins comprising the fragments or the full length protein. For example, the signal peptide may be deleted. A variant may have an amino acid sequence at least about any of 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the naturally occurring protein sequence. A functional variant may have the same or similar hyperpolarization function or depolarization function as the naturally occurring protein.
In some embodiments, the NpHR is eNpHR3.0 or eNpHR3.1 (See www.stanford.edu/group/dlab/optogenetics/sequence_info.html). In some embodiments, the light-responsive opsin is a C1V1 chimeric protein or a C1V1-E162 (SEQ ID NO:10), C1V1-E122 (SEQ ID NO:9), or C1V1-E122/E162 (SEQ ID NO:11) mutant chimeric protein (See, Yizhar et al, Nature, 2011, 477(7363):171-78 and www.stanford.edu/group/dlab/optogenetics/sequence_info.html). In some embodiments, the light-responsive opsin is a SFO (SEQ ID NO: 6) or SSFO (SEQ ID NO: 7) (See, Yizhar et al, Nature, 2011, 477(7363):171-78; Berndt et al., Nat. Neurosci., 12(2):229-34 and www.stanford.edu/group/dlab/optogenetics/sequence_info.html).
In some embodiments, the light-activated protein is a NpHR opsin comprising an amino acid sequence at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identical to the sequence shown in SEQ. ID NO:1. In some embodiments, the NpHR opsin further comprises an endoplasmic reticulum (ER) export signal and/or a membrane trafficking signal. For example, the NpHR opsin comprises an amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1 and an endoplasmic reticulum (ER) export signal. In some embodiments, the amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1 is linked to the ER export signal through a linker. In some embodiments, the ER export signal comprises the amino acid sequence FXYENE, where X can be any amino acid. In another embodiment, the ER export signal comprises the amino acid sequence VXXSL, where X can be any amino acid. In some embodiments, the ER export signal comprises the amino acid sequence FCYENEV. In some embodiments, the NpHR opsin comprises an amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1, an ER export signal, and a membrane trafficking signal. In other embodiments, the NpHR opsin comprises, from the N-terminus to the C-terminus, the amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1, the ER export signal, and the membrane trafficking signal. In other embodiments, the NpHR opsin comprises, from the N-terminus to the C-terminus, the amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1, the membrane trafficking signal, and the ER export signal. In some embodiments, the membrane trafficking signal is derived from the amino acid sequence of the human inward rectifier potassium channel K ir 2.1. In some embodiments, the membrane trafficking signal comprises the amino acid sequence K S R I T S E G E Y I P L D Q I D I N V. In some embodiments, the membrane trafficking signal is linked to the amino acid sequence at least 95% identical to the sequence shown in SEQ ID NO:1 by a linker. In some embodiments, the membrane trafficking signal is linked to the ER export signal through a linker. The linker may comprise any of 5, 10, 20, 30, 40, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 400, or 500 amino acids in length. The linker may further comprise a fluorescent protein, for example, but not limited to, a yellow fluorescent protein, a red fluorescent protein, a green fluorescent protein, or a cyan fluorescent protein. In some embodiments, the light-activated opsin further comprises an N-terminal signal peptide. In some embodiments, the light-activated opsin comprises the amino acid sequence of SEQ ID NO:2. In some embodiments, the light-activated protein comprises the amino acid sequence of SEQ ID NO:3.
In some embodiments, the light-activated opsin is a chimeric protein derived from VChR1 from Volvox carteri and ChR1 from Chlamydomonas reinhardti . In some embodiments, the chimeric protein comprises the amino acid sequence of VChR1 having at least the first and second transmembrane helices replaced by the corresponding first and second transmembrane helices of ChR1. In other embodiments, the chimeric protein comprises the amino acid sequence of VChR1 having the first and second transmembrane helices replaced by the corresponding first and second transmembrane helices of ChR1 and further comprises at least a portion of the intracellular loop domain located between the second and third transmembrane helices replaced by the corresponding portion from ChR1. In some embodiments, the entire intracellular loop domain between the second and third transmembrane helices of the chimeric light-activated protein can be replaced with the corresponding intracellular loop domain from ChR1. In some embodiments, the light-activated chimeric protein comprises an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the sequence shown in SEQ ID NO:8 without the signal peptide sequence. In some embodiments, the light-activated chimeric protein comprises an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the sequence shown in SEQ ID NO:8. C1V1 chimeric light-activated opsins that may have specific amino acid substitutions at key positions throughout the retinal binding pocket of the VChR1 portion of the chimeric polypeptide. In some embodiments, the C1V1 protein has a mutation at amino acid residue E122 of SEQ ID NO:8. In some embodiments, the C1V1 protein has a mutation at amino acid residue E162 of SEQ ID NO:8. In other embodiments, the C1V1 protein has a mutation at both amino acid residues E162 and E122 of SEQ ID NO:8. In some embodiments, each of the disclosed mutant C1V1 chimeric proteins can have specific properties and characteristics for use in depolarizing the membrane of an animal cell in response to light.
As used herein, a vector comprises a nucleic acid encoding a light-responsive opsin described herein and the nucleic acid is operably linked to a promoter that controls the specific expression of the opsin in the glutamatergic pyramidal neurons. Any vectors that are useful for delivering a nucleic acid to glutamatergic pyramidal neurons may be used. Vectors include viral vectors, such as AAV vectors, retroviral vectors, adenoviral vectors, HSV vectors, and lentiviral vectors. Examples of AAV vectors are AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, AAV13, AAV14, AAV15, and AAV16. A CaMKIIα promoter and any other promoters that can control the expression of the opsin in the glutamatergic pyramidal neurons may be used.
An “individual” is a mammal, such as a human. Mammals also include, but are not limited to, farm animals, sport animals, pets (such as cats, dogs, horses), primates, mice and rats. An “animal” is a non-human mammal.
As used herein, “treatment” or “treating” or “alleviation” is an approach for obtaining beneficial or desired results including and preferably clinical results. For purposes of this invention, beneficial or desired clinical results include, but are not limited to, one or more of the following: showing observable and/or measurable reduction in one or more signs of the disease (such as anxiety), decreasing symptoms resulting from the disease, increasing the quality of life of those suffering from the disease, decreasing the dose of other medications required to treat the disease, and/or delaying the progression of the disease.
As used herein, an “effective dosage” or “effective amount” of a drug, compound, or pharmaceutical composition is an amount sufficient to effect beneficial or desired results. For therapeutic use, beneficial or desired results include clinical results such as decreasing one or more symptoms resulting from the disease, increasing the quality of life of those suffering from the disease, decreasing the dose of other medications required to treat the disease, enhancing effect of another medication such as via targeting, and/or delaying the progression of the disease. As is understood in the clinical context, an effective dosage of a drug, compound, or pharmaceutical composition may or may not be achieved in conjunction with another drug, compound, pharmaceutical composition, or another treatment. Thus, an “effective dosage” may be considered in the context of administering one or more therapeutic agents or treatments, and a single agent may be considered to be given in an effective amount if, in conjunction with one or more other agents or treatments, a desirable result may be or is achieved.
The above overview is not intended to describe each illustrated embodiment or every implementation of the present disclosure.
DETAILED DESCRIPTION AND EXAMPLE EXPERIMENTAL EMBODIMENTS
The present disclosure is believed to be useful for controlling anxiety states and/or symptoms of anxiety. Specific applications of the present invention relate to optogenetic systems or methods that correlate temporal, spatio and/or cell-type control over a neural circuit associated with anxiety states and/or symptoms thereof. As many aspects of the example embodiments disclosed herein relate to and significantly build on previous developments in this field, the following discussion summarizes such previous developments to provide a solid understanding of the foundation and underlying teachings from which implementation details and modifications might be drawn, including those found in the Examples. It is in this context that the following discussion is provided and with the teachings in the references incorporated herein by reference. While the present invention is not necessarily limited to such applications, various aspects of the invention may be appreciated through a discussion of various examples using this context.
Anxiety refers to a sustained state of heightened apprehension in the absence of an immediate threat, which in disease states becomes severely debilitating. Embodiments of the present disclosure are directed toward the use of one or more of cell type-specific optogenetic tools with two-photon microscopy, electrophysiology, and anxiety assays to study and develop treatments relating to neural circuits underlying anxiety-related behaviors.
Aspects of the present disclosure are related to the optogenetic targeting of specific projections of the brain, rather than cell types, in the study of neural circuit function relevant to psychiatric disease.
Consistent with particular embodiments of the present disclosure, temporally-precise optogenetic stimulation of basolateral amygdala (BLA) terminals in the central nucleus of the amygdala (CeA) are used to produce a reversible anxiolytic effect. The optogenetic stimulation can be implemented by viral transduction of BLA with a light-responsive opsin, such as ChR2, followed by restricted illumination in downstream CeA.
Consistent with other embodiments of the present disclosure, optogenetic inhibition of the basolateral amygdala (BLA) terminals in the central nucleus of the amygdala (CeA) are used to increase anxiety-related behaviors. The optogenetic stimulation can be implemented by viral transduction of BLA with a light-responsive opsin, such as eNpHR3.0, followed by restricted illumination in downstream CeA.
Embodiments of the present disclosure are directed towards the specific targeting of neural cell populations, as anxiety-based effects were not observed with direct optogenetic control of BLA somata. For instance, targeting of specific BLA-CeA projections as circuit elements have been experimentally shown to be sufficient for endogenous anxiety control in the mammalian brain.
Consistent with embodiments of the present disclosure, the targeting of the specific BLA-CeA projections as circuit elements is based upon a number of factors discussed in more detail hereafter. The amygdala is composed of functionally and morphologically heterogeneous subnuclei with complex interconnectivity. A primary subdivision of the amygdala is the basolateral amygdala complex (BLA), which encompasses the lateral (LA), basolateral (BL) and basomedial (BM) amygdala nuclei (˜90% of BLA neurons are glutamatergic). In contrast, the central nucleus of the amygdala (CeA), which is composed of the centrolateral (CeL) and centromedial (CeM) nuclei, is predominantly (˜95%) comprised of GABAergic medium spiny neurons. The BLA is ensheathed in dense clusters of GABAergic intercalated cells (ITCs), which are functionally distinct from both local interneurons and the medium spiny neurons of the CeA. The primary output nucleus of the amygdala is the CeM, which, when chemically or electrically excited, is believed to mediate autonomic and behavioral responses that are associated with fear and anxiety via projections to the brainstem. While the CeM is not directly controlled by the primary amygdala site of converging environmental and cognitive information (LA), LA and BLA neurons excite GABAergic CeL neurons, which can provide feed-forward inhibition onto CeM “output” neurons and reduce amygdala output. The BLA-CeL-CeM is a less-characterized pathway suggested to be involved not in fear extinction but in conditioned inhibition. The suppression of fear expression, possibly due to explicit unpairing of the tone and shock, suggested to be related to the potentiation of BLA-CeL synapses.
BLA cells have promiscuous projections throughout the brain, including to the bed nucleus of the stria terminalis (BNST), nucleus accumbens, hippocampus and cortex. Aspects of the present disclosure relate to methods for selective control of BLA terminals in the CeL, without little or no direct affect/control of other BLA projections. Preferential targeting of BLA-CeL synapses can be facilitated by restricting opsin gene expression to BLA glutamatergic projection neurons and by restricting light delivery to the CeA.
For instance, control of BLA glutamatergic projection neurons can be achieved with an adeno-associated virus (AAV5) vector carrying light-activated optogenetic control genes under the control of a CaMKIIα promoter. Within the BLA, CaMKIIα is only expressed in glutamatergic pyramidal neurons, not in local interneurons or intercalated cells.
FIG. 1 shows a system for providing optogenetic targeting of specific projections of the brain, consistent with an embodiment of the present disclosure. For instance, a beveled guide cannula can be used to direct light, e.g., prevent light delivery to the BLA and allow selective illumination of the CeA. This preferential delivery of light to the CeA projection can be accomplished using stereotaxic guidance along with implantation over the CeL. Geometric and functional properties of the resulting light distribution can be quantified both in vitro and in vivo, e.g., using in vivo electrophysiological recordings to determine light power parameters for selective control of BLA terminals but not BLA cell bodies. Experimental results, such as those described in the Examples, support that such selective excitation or inhibition result in significant, immediate and reversible anxiety-based effects.
Embodiments of the present disclosure are directed toward the above realization being applied to various ones of the anatomical, functional, structural, and circuit targets identified herein. For instance, the circuit targets can be studied to develop treatments for the psychiatric disease of anxiety. These treatments can include, as non-limiting examples, pharmacological, electrical, magnetic, surgical and optogenetic, or other treatment means.
FIG. 2 shows a flow diagram for use of an anxiety-based circuit model, consistent with an embodiment of the present disclosure. An optogenetic delivery device, such as a. viral delivery device, is generated 202. This delivery device can be configured to introduce optically responsive opsins to the target cells and may include targeted promoters for specific cell types. The delivery device can then be stereotaxically (or otherwise) injected 204 into the BLA. A light delivery device can then be surgical implanted 206. This light delivery device can be configured to provide targeted illumination (e.g., using a directional optical element). The target area is then illuminated 208. The target area can be, for example, the BLA-CeA. The effects thereof can then be monitored and/or assessed 210. This can also be used in connection with treatments or drug screening.
Various embodiments of the present disclosure relate to the use of the identified model for screening new treatments for anxiety. For instance, anxiety can be artificially induced or repressed using the methods discussed herein, while pharmacological, electrical, magnetic, surgical, or optogenetic treatments are then applied and assessed. In other embodiments of the present disclosure, the model can be used to develop an in vitro approximation or simulation of the identified circuit, which can then be used in the screening of devices, reagents, tools, technologies, methods and approaches and for studying and probing anxiety and related disorders. This study can be directed towards, but not necessarily limited to, identifying phenotypes, endophenotypes, and treatment targets.
Embodiments of the present disclosure are directed toward modeling the BLA-CeL pathway as an endogenous neural substrate for bidirectionally modulating the unconditioned expression of anxiety. Certain embodiments are directed toward other downstream circuits, such as CeA projections to the BNST, for their role in the expression of anxiety or anxiety-related behaviors. For instance, it is believed that corticotropin releasing hormone (CRH) networks in the BNST may be critically involved in modulating anxiety-related behaviors, as the CeL is a primary source of CRH for the BNST. Other neurotransmitters and neuromodulators may modulate or gate effects on distributed neural circuits, including serotonin, dopamine, acetylcholine, glycine, GABA and CRH. Still other embodiments are directed toward control of the neural circuitry converging to and diverging from this pathway, as parallel or downstream circuits of the BLA-CeL synapse are believed to contribute to the modulation or expression of anxiety phenotypes. Moreover, upstream of the amygdala, this microcircuit is well-positioned to be recruited by top-down cortical control from regions important for processing fear and anxiety, including the prelimbic, infralimbic and insular cortices that provide robust innervation to the BLA and CeL.
Experimental results based upon the BLA anatomy suggest that the populations of BLA neurons projecting to CeL and CeM neurons are largely non-overlapping. In natural states, the CeL-projecting BLA neurons may excite CeM-projecting BLA neurons in a microcircuit homeostatic mechanism, which can then be used to study underlying anxiety disorders when there are synaptic changes that skew the balance of the circuit to allow uninhibited CeM activation.
The embodiments and specific applications discussed herein (including the Examples) may be implemented in connection with one or more of the above-described aspects, embodiments and implementations, as well as with those shown in the figures and described below. Reference may be made to the following Example, which is fully incorporated herein by reference. For further details on light-responsive molecules and/or opsins, including methodology, devices and substances, reference may also be made to the following background publications: U.S. Patent Publication No. 2010/0190229, entitled “System for Optical Stimulation of Target Cells” to Zhang et al.; U.S. Patent Publication No. 2010/0145418, also entitled “System for Optical Stimulation of Target Cells” to Zhang et al.; U.S. Patent Publication No. 2007/0261127, entitled “System for Optical Stimulation of Target Cells” to Boyden et al.; and PCT WO 2011/116238, Entitled “Light Sensitive Ion Passing Molecules”. These applications form part of the patent document and are fully incorporated herein by reference. Consistent with these publications, numerous opsins can be used in mammalian cells in vivo and in vitro to provide optical stimulation and control of target cells. For example, when ChR2 is introduced into an electrically-excitable cell, such as a neuron, light activation of the ChR2 channelrhodopsin can result in excitation and/or firing of the cell. In instances when NpHR is introduced into an electrically-excitable cell, such as a neuron, light activation of the NpHR opsin can result in inhibition of firing of the cell. These and other aspects of the disclosures of the above-referenced patent applications may be useful in implementing various aspects of the present disclosure.
While the present disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in further detail. It should be understood that the intention is not to limit the disclosure to the particular embodiments and/or applications described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
Examples
Introduction
Anxiety is a sustained state of heightened apprehension in the absence of immediate threat, which in disease states becomes severely debilitating 1 . Anxiety disorders represent the most common of the psychiatric diseases (with 28% lifetime prevalence) 2 , and have been linked to the etiology of major depression and substance abuse 3-5 . While the amygdala, a brain region important for emotional processing 9-17 , has long been hypothesized to play a role in anxiety 18-23 , the neural mechanisms which control and mediate anxiety have yet to be identified. Here, we combine cell type-specific optogenetic tools with two-photon microscopy, electrophysiology, and anxiety assays in freely-moving mice to identify neural circuits underlying anxiety-related behaviors. Capitalizing on the unique capability of optogenetics 24-26 to control not only cell types, but also specific connections between cells, we observed that temporally-precise optogenetic stimulation of basolateral amygdala (BLA) terminals in the central nucleus of the amygdala (CeA), resolved by viral transduction of BLA with ChR2 followed by restricted illumination in downstream CeA, exerted a profound, immediate, and reversible anxiolytic effect. Conversely, selective optogenetic inhibition of the same defined projection with eNpHR3.0 25 potently, swiftly, and reversibly increased anxiety-related behaviors. Importantly, these effects were not observed with direct optogenetic control of BLA somata themselves. Together, these results implicate specific BLA-CeA projections as circuit elements both necessary and sufficient for endogenous anxiety control in the mammalian brain, and demonstrate the importance of optogenetically targeting specific projections, rather than cell types, in the study of neural circuit function relevant to psychiatric disease.
Despite the high prevalence and severity 1 of anxiety disorders, the corresponding neural circuit substrates are poorly understood, impeding the development of safe and effective treatments. Available treatments tend to be inconsistently effective or, in the case of benzodiazepines, addictive and linked to significant side effects including sedation and respiratory suppression that can cause cognitive impairment and death 27,28 . A deeper understanding of anxiety control mechanisms in the mammalian brain 29,30 is necessary to develop more efficient treatments that have fewer side-effects. Of particular interest and novelty would be the possibility of recruiting native pathways for anxiolysis.
The amygdala is critically involved in processing associations between neutral stimuli and positive or negative outcomes, and has also been implicated in processing unconditioned emotional states. While the amygdala microcircuit has been functionally dissected in the context of fear conditioning, amygdalar involvement has been implicated in a multitude of other functions and emotional states, including unconditioned anxiety. The amygdala is composed of functionally and morphologically heterogeneous subnuclei with complex interconnectivity. A primary subdivision of the amygdala is the basolateral amygdala complex (BLA), which encompasses the lateral (LA), basolateral (BL) and basomedial (BM) amygdala nuclei (˜90% of BLA neurons are glutamatergic) 33,34 . In contrast, the central nucleus of the amygdala (CeA), which is composed of the centrolateral (CeL) and centromedial (CeM) nuclei, is predominantly (˜95%) comprised of GABAergic medium spiny neurons 35 . The BLA is ensheathed in dense clusters of GABAergic intercalated cells (ITCs), which are functionally distinct from both local interneurons and the medium spiny neurons of the CeA 36, 37 . The primary output nucleus of the amygdala is the CeM, 32, 35, 38-40 which when chemically or electrically excited mediates autonomic and behavioral responses associated with fear and anxiety via projections to the brainstem 6, 12, 32, 35 . While the CeM is not directly controlled by the primary amygdala site of converging environmental and cognitive information (LA) 12, 38, 41 , LA and BLA neurons excite GABAergic CeL neurons 42 which can provide feed-forward inhibition onto CeM 40, 46 “output” neurons and reduce amygdala output. The BLA-CeL-CeM is a less-characterized pathway suggested to be involved not in fear extinction but in conditioned inhibition, the suppression of fear expression due to explicit unpairing of the tone and shock, due to the potentiation of BLA-CeL synapses 47 . Although fear is characterized to be a phasic state triggered by an external cue, while anxiety is a sustained state that may occur in the absence of an external trigger, we wondered if circuits modulating conditioned inhibition of fear might also be involved in modulating unconditioned inhibition of anxiety.
Materials and Methods
Subjects: Male C57BL/6 mice, aged 4-6 weeks at the start of experimental procedures, were maintained with a reverse 12-hr light/dark cycle and given food and water ad libitum. Animals shown in FIGS. 3, 4 and 5 (mice in the ChR2 Terminals, EYFP Terminals and ChR2 Cell Bodies groups) were all single-housed in a typical high-traffic mouse facility to increase baseline anxiety levels. Each mouse belonged to a single treatment group. Animals shown in FIG. 6 (Bilateral EYFP and eNpHR 3.0 groups) were group-housed in a special low-traffic facility to decrease baseline anxiety levels. Animal husbandry and all aspects of experimental manipulation of our animals were in accordance with the guidelines from the National Institute of Health and have been approved by members of the Stanford Institutional Animal Care and Use Committee.
Optical Intensity Measurements: Light transmission measurements were conducted with blocks of brain tissue from acutely sacrificed mice. The tissue was then placed over the photodetector of a power meter (ThorLabs, Newton, N.J.) to measure the light power of the laser penetrated the tissue. The tip of a 300 um diameter optical fiber was coupled to a 473 nm blue laser (OEM Laser Systems, East Lansing, Mich.). To characterize the light transmission to the opposite side of the bevel, the photodetector of the power meter was placed parallel to the beveled cannula. For visualization of the light cone, we used Fluorescein isothiocyanate-dextran (FD150s; Sigma, Saint Louis, Mo.) at approximately 5 mg/ml placed in a cuvette with the optical fibers either with or without beveled cannula shielding aimed perpendicularly over the fluorescein solution. Power density at specific depths were calculated considering both fractional decrease in intensity due to the conical output of light from the optical fiber and the loss of light due to scattering in tissue (Aravanis et al., J Neural Eng, 4:S143-156, 2007) (Gradinaru et al., J Neurosci, 27:14231-14238, 2007). The half-angle of divergence θ div for a multimode optical fiber, which determines the angular spread of the output light, is
θ
div
=
sin
-
1
(
NA
fib
n
tis
)
where n tis is the index of refraction of gray matter (1.36, Vo-Dinh T 2003, Biomedical Photonics Handbook (Boca Raton, Fla.: CRC Press)) and NA fib (0.37) is the numerical aperture of the optical fiber. The fractional change in intensity due to the conical spread of the light with distance (z) from the fiber end was calculated using trigonometry
I
(
z
)
I
(
z
=
0
)
=
ρ
2
(
z
+
ρ
)
2
,
where
ρ
=
r
(
n
NA
)
2
-
1
and r is the radius of the optical fiber (100 μm).
The fractional transmission of light after loss due to scattering was modeled as a hyperbolic function using empirical measurements and the Kubelka-Munk model 1, 2 , and the combined product of the power density at the tip of the fiber and the fractional changes due to the conical spread and light scattering, produces the value of the power density at a specific depth below the fiber.
Virus Construction and Packaging:
The recombinant AAV vectors were serotyped with AAV 5 coat proteins and packaged by the viral vector core at the University of North Carolina. Viral titers were 2×10 e 12 particles/mL, 3×10 e 12 particles/mL, 4×10 e 12 particles/mL respectively for AAV-CaMKIIα-hChR2(H134R)-EYFP, AAV-CaMKIIα-EYFP, and AAV-CaMKIIα-eNpHR 3.0-EYFP. The pAAV-CaMKIIα-eNpHR3.0-EYFP plasmid was constructed by cloning CaMKIIα-eNpHR3.0-EYFP into an AAV backbone using MluI and EcoRI restriction sites. Similarly, The pAAV-CaMKIIα-EYFP plasmid was constructed by cloning CaMKIIα-EYFP into an AAV backbone using MluI and EcoRI restriction sites. The maps are available online at www.optogenetics.org, which are incorporated herein by reference.
Stereotactic Injection and Optical Fiber Placement:
All surgeries were performed under aseptic conditions under stereotaxic guidance. Mice were anaesthetized using 1.5-3.0% isoflourane. All coordinates are relative to bregma in mm 3 . In all experiments, both in vivo and in vitro, virus was delivered to the BLA only, and any viral expression in the CeA rendered exclusion from all experiments. Cannula guides were beveled to form a 45-55 degree angle for the restriction of the illumination to the CeA. The short side of the beveled cannula guide was placed antero-medially, the long side of the beveled cannula shielded the posterior-lateral portion of the light cone, facing the opposite direction of the viral injection needle. To preferentially target BLA-CeL synapses, we restricted opsin gene expression to BLA glutamatergic projection neurons and restricted light delivery to the CeA. Control of BLA glutamatergic projection neurons was achieved using an adeno-associated virus (AAV5) vector carrying light-activated optogenetic control genes under the control of a CaMKIIα promoter. Within the BLA, CaMKIIα is only expressed in glutamatergic pyramidal neurons, not in local interneurons 4 . Mice in the ChR2 Terminals and EYFP Terminals groups received unilateral implantations of beveled cannulae for the optical fiber (counter-balanced for hemisphere), while mice in the eNpHR 3.0 or respective EYFP group received bilateral implantations of the beveled cannulae over the CeA (−1.06 mm anteroposterior (AP); ±2.25 mm mediolateral (ML); and −4.4 mm dorsoventral (DV); PlasticsOne, Roanoke, Va.) 3 . Mice in the ChR2 Cell Bodies groups received unilateral implantation of a Doric patchcord chronically implantable fiber (NA=0.22; Doric lenses, Quebec, Canada) over the BLA at (−1.6 mm AP; ±3.1 mm ML; −4.5 mm DV) 3 . For all mice, 0.5 μl of purified AAV 5 was injected unilaterally or bilaterally in the BLA (±3.1 mm AP, 1.6 mm ML, −4.9 mm DV) 3 using beveled 33 or 35 gauge metal needle facing posterolateral side to restrict the viral infusion to the BLA. 10 μl Hamilton microsyringe (nanofil; WPI, Sarasota, Fla.) were used to deliver concentrated AAV solution using a microsyringe pump (UMP3; WPI, Sarasota, Fla.) and its controller (Micro4; WPI, Sarasota, Fla.). Then, 0.5 μl of virus solution was injected at each site at a rate of 0.1 μl per min. After injection completion, the needle was lifted 0.1 mm and stayed for 10 additional minutes and then slowly withdrawn. One layer of adhesive cement (C&B metabond; Parkell, Edgewood, N.Y.) followed by cranioplastic cement (Dental cement; Stoelting, Wood Dale, Ill.) was used to secure the fiber guide system to the skull. After 20 min, the incision was closed using tissue adhesive (Vetbond; Fisher, Pittsburgh, Pa.). The animal was kept on a heating pad until it recovered from anesthesia. A dummy cap (rat: C312G, mouse: C313G) was inserted to keep the cannula guide patent. Behavioral and electrophysiological experiments were conducted 4-6 weeks later to allow for viral expression.
In Vivo Recordings:
Simultaneous optical stimulation of central amygdala (CeA) and electrical recording of basolateral amygdala (BLA) of adult male mice previously (4-6 weeks prior) transduced in BLA with AAV-CaMKIIα-ChR2-eYFP viral construct was carried out as described previously (Gradinaru et al., J Neurosci, 27:14231-14238, 2007). Animals were deeply anesthetized with isoflurane prior to craniotomy and had negative toe pinch. After aligning mouse stereotaxically and surgically removing approximately 3 mm 2 skull dorsal to amygdala. Coordinates were adjusted to allow for developmental growth of the skull and brain, as mice received surgery when they were 4-6 weeks old and experiments were performed when the mice were 8-10 weeks old (centered at −1.5 mm AP, ±2.75 mm ML) 3 , a 1 Mohm 0.005-in extracellular tungsten electrode (A-M systems) was stereotactically inserted into the craniotomized brain region above the BLA (in mm: −1.65 AP, ±3.35 ML, −4.9 DV) 3 . Separately, a 0.2 N.A. 200 μm core diameter fiber optic cable (Thor Labs) was stereotactically inserted into the brain dorsal to CeA (−1.1 AP, ±2.25 ML, −4.2 DV) 3 . After acquiring a light evoked response, voltage ramps were used to vary light intensity during stimulation epochs (20 Hz, 5 ms pulse width) 2 s in length. After acquiring optically evoked signal, the exact position of the fiber was recorded, the fiber removed from the brain, inserted into a custom beveled cannula, reinserted to the same position, and the same protocol was repeated. In most trials, the fiber/cannula was then extracted from the brain, the cannula removed, and the bare fiber reinserted to ensure the fidelity of the population of neurons emitting the evoked signal. Recorded signals were bandpass filtered between 300 Hz and 20 kHz, AC amplified either 1000× or 10000× (A-M Systems 1800), and digitized (Molecular Devices Digidata 1322A) before being recorded using Clampex software (Molecular Devices). Clampex software was used for both recording field signals and controlling a 473 nm (OEM Laser Systems) solidstate laser diode source coupled to the optrode. Light power was titrated between <1 mW (˜14 mW/mm 2 ) and 28 mW (˜396 mW/mm 2 ) from the fiber tip and measured using a standard light power meter (ThorLabs). Electrophysiological recordings were initiated approximately 1 mm dorsal to BLA after lowering isoflurane anesthesia to a constant level of 1%. Optrode was lowered ventrally in ˜0.1 mm steps until localization of optically evoked signal.
Behavioral Assays:
All animals used for behavior received viral transduction of BLA neurons and the implantation enabling unilateral (for ChR2 groups and controls) or bilateral (for eNpHR3.0 groups and controls) light delivery. For behavior, multimode optical fibers (NA 0.37; 300 μm core, BFL37-300; ThorLabs, Newton, N.J.) were precisely cut to the optimal length for restricting the light to the CeA, which was shorter than the long edge of the beveled cannula, but longer than the shortest edge of the beveled cannula. For optical stimulation, the fiber was connected to a 473 nm or 594 nm laser diode (OEM Laser Systems, East Lansing, Mich.) through an FC/PC adapter. Laser output was controlled using a Master-8 pulse stimulator (A.M.P.I., Jerusalem, Israel) to deliver light trains at 20 Hz, 5 ms pulse-width for 473 nm light, and constant light for 594 nm light experiments. All included animals had the center of the viral injection located in the BLA, though there was sometimes leak to neighboring regions or along the needle tract. Any case in which there was any detectable viral expression in the CeA, the animals were excluded. All statistically significant effects of light were discussed, and undiscussed comparisons did not show detectable differences.
The elevated plus maze was made of plastic and consisted of two light gray open arms (30×5 cm), two black enclosed arms (30×5×30 cm) extending from a central platform (5×5×5 cm) at 90 degrees in the form of a plus. The maze was placed 30 cm above the floor. Mice were individually placed in the center. 1-5 minutes were allowed for recovery from handling before the session was initiated. Video tracking software (BiObserve, Fort Lee, N.J.) was used to track mouse location, velocity and movement of head, body and tail. All measurements displayed were relative to the mouse body. Light stimulation protocols are specified by group. ChR2:BLA-CeA mice and corresponding controls groups (EYFP:BLA-CeA and ChR2:BLA Somata) were singly-housed in a high-stress environment for at least 1 week prior to anxiety assays: unilateral illumination of BLA terminals in the CeA at 7-8 mW (˜106 mW/mm 2 at the tip of the fiber, ˜6.3 mW/mm 2 at CeL and ˜2.4 mW/mm 2 at the CeM) of 473 nm light pulse trains (5 ms pulses at 20 Hz). For the ChR2 Cell Bodies group BLA neurons were directly illuminated with a lower light power because illumination with 7-8 mW induced seizure activity, so we unilaterally illuminated BLA neurons at 3-5 mW (˜57 mW/mm 2 ) of 473 nm light pulse trains (5 ms pulses at 20 Hz). For the eNpHR 3.0 and corresponding EYFP group, all mice were group-housed and received bilateral viral injections and bilateral illumination of BLA terminals in the CeA at 4-6 mW (˜71 mW/mm 2 at the tip of the fiber, ˜4.7 mW/mm 2 at the CeL and ˜1.9 mW/mm 2 at the CeM) of 594 nm light with constant illumination throughout the 5-min light on epoch. The 15-min session was divided into 35-min epochs, the first epoch there was no light stimulation (off), the second epoch light was delivered as specified above (on), and the third epoch there was no light stimulation (off).
The open-field chamber (50×50 cm) and the open field was divided into a central field (center, 23×23 cm) and an outer field (periphery). Individual mice were placed in the periphery of the field and the paths of the animals were recorded by a video camera. The total distance traveled was analyzed by using the same video-tracking software, Viewer 2 (BiObserve, Fort Lee, N.J.). The open field assessment was made immediately after the elevated-plus maze test. The open field test consisted of an 18-min session in which there were six 3-min epochs. The epochs alternated between no light and light stimulation periods, beginning with a light off epoch. For all analyses and charts where only “off” and “on” conditions are displayed, the 3 “off” epochs were pooled and the 3 “on” epochs were pooled.
For the glutamate receptor antagonist manipulation, a glutamate antagonist solution consisting of 22.0 mM of NBQX and 38.0 mM of D-APV (Tocris, Ellisville, Mo.) dissolved in saline (0.9% NaCl). 5-15 min before the anxiety assays, 0.3 μl of the glutamate antagonist solution was infused into the CeA via an internal infusion needle, inserted into the same guide cannulae used for light delivery via optical fiber, that was connected to a 10-μl Hamilton syringe (nanofil; WPI, Sarasota, Fla.). The flow rate (0.1 μl per min) was regulated by a syringe pump (Harvard Apparatus, Mass.). Placements of the viral injection, guide cannula and chronically-implanted fiber were histologically verified as indicated in FIGS. 7 and 10 .
Two-Photon Optogenetic Circuit Mapping and Ex Vivo Electrophysiological Recording:
Mice were injected with AAV5-CaMKIIα-ChR2-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Coronal slices containing the BLA and CeA were prepared to examine the functional connectivity between the BLA and the CeA. Two-photon images and electrophysiological recordings were made under the constant perfusion of aCSF, which contained (in mM): 126 NaCl, 26 NaHCO 3 , 2.5 KCl, 1.25 NaH 2 PO 4 , 1 MgCl 2 , 2 CaCl 2 , and 10 glucose. All recordings were at 32° C. Patch electrodes (4-6 MOhms) were filled (in mM): 10 HEPES, 4 Mg-ATP, 0.5 MgCl 2 , 0.4 Na 3 -GTP, 10 NaCl, 140 potassium gluconate, and 80 Alexa-Fluor 594 hydrazide (Molecular Probes, Eugene Oreg.). Whole-cell patch-clamp recordings were performed in BLA, CeL and CeM neurons, and cells were allowed to fill for approximately 30 minutes before imaging on a modified two-photon microscope (Prairie Microscopes, Madison Wis.) where two-photon imaging, whole-cell recording and optogenetic stimulation could be done simultaneously. Series resistance of the pipettes was usually 10-20 MOhms Blue light pulses were elicited using a 473 nm LED at −7 mW/mm 2 (Thorlabs, Newton N.J.) unless otherwise noted. A Coherent Ti-Saphire laser was used to image both ChR2-YFP (940 nm) and Alexa-Fluor 594 (800 nm). A FF560 dichroic with filters 630/69 and 542/27 (Semrock, Rochester N.Y.) was also used to separate both molecules' emission. All images were taken using a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). In order to isolate fibers projecting to CeL from the BLA and examine responses in the CeM, slices were prepared as described above with the BLA excluded from illumination. Whole-cell recordings were performed in the CeM with illumination from the objective aimed over the CeL. To further ensure activation of terminals from the BLA to CeL was selective, illumination was restricted to a ˜125 μm diameter around the center of the CeL. Here, blue light pulses were elicited using an XCite halogen light source (EXPO, Mississauga, Ontario) with a 470/3 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). For functional mapping, we first recorded from a BLA neuron expressing ChR2 and simultaneously collected electrophysiological recordings and filled the cell with Alexa-Fluor 594 hydrazide dye to allow for two-photon imaging. Two-photon z-stacks were collected at multiple locations along the axon of the filled BLA neuron. We then followed the axon of the BLA neuron projecting to the CeL nucleus and recorded from a CeL neuron in the BLA terminal field. We then simultaneously recorded from a CeL neuron, filled the cell with dye and performed two-photon live imaging before following the CeL neuronal axons to the CeM. We then repeated this procedure in a CeM neuron, but moved the light back to the terminal field in the CeL to mimic the preferential illumination of BLA-CeL synapses with the same stimulation parameters as performed in vivo. Voltage-clamp recordings were made at both −70 mV, to isolate EPSCs, and at 0 mV, to isolate IPSCs. EPSCs were confirmed to be EPSCs via bath application of the glutamate receptor antagonists (n=5), NBQX (22 μm) and AP5 (38 μM), IPSCs were confirmed to be IPSCs via bath application of bicuculline (10 μM; n=2), which abolished them, respectively. We also performed current-clamp recordings when the cell was resting at approximately −70 mV.
For the characterization of optogenetically-driven antidromic stimulation in BLA axon terminals, animals were injected with AAV5-CaMKIIα-ChR2-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Slice preparation was the same as above. To the aCSF we added 0.1 mM picrotoxin, 10 μM CNQX and 25 μM AP5 (Sigma, St. Louis, Mo.). Whole-cell patch-clamp recordings were performed in BLA neurons and were allowed to fill for approximately 30 minutes before two-photon imaging. Series resistance of the pipettes was usually 10-20 MOhms. All images were taken using a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). Blue light pulses were elicited using an XCite halogen light source (EXPO, Mississauga, Ontario) with a 470/30 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). Two-photon z-stacks were collected at multiple locations along the axon of the filled BLA neuron. Only neurons whose axons could be visualized for over ˜300 μm diameter towards the CeL nucleus were included for the experiment, and neurons that had processes going in all directions were also excluded. Stimulation on/off axon was accomplished by moving the slice relative to a ˜125 μm diameter blue light spot. In order to calibrate the slice for correct expression, whole-cell patch-clamp was performed on a CeL cell and a ˜125 μm diameter spot blue pulse was used to ensure that synaptic release from the BLA terminals on to the CeL neuron was reliable.
For the dissection of direct and indirect projections to CeM, animals were injected with AAV 5 -CaMKIIα-ChR2-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Slice preparation was the same as above. Light was delivered through a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). Prior to whole cell patch clamping in the CeM nucleus, the location of the CeL nucleus was noted in order to revisit it with the light spot restricted to this region. Whole-cell patch-clamp recordings were performed in CeM neurons. Series resistance of the pipettes was usually 10-20 MOhms. Blue light pulses were elicited using a XCite halogen light source (EXPO, Mississauga, Ontario) with a 470/30 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). During CeM recordings, broad illumination (˜425-450 μm in diameter) of BLA terminals in the CeA and 20 Hz, 5 ms light train for 2 s was applied. Voltage-clamp recordings were made at 70 mV and 0 mV to isolate EPSCs and IPSCs respectively. Current-clamp recordings were also made. Then, illumination was moved to the CeL using a restricted light spot ˜125 μm in diameter. We again performed voltage clamp recordings at −70 mV and 0 mV and used 20 Hz, 5 ms light train for 2 s. For the CeM neuron spiking inhibition experiments, in current-clamp, we applied the minimal current step required to induce spiking (˜60 pA) and simultaneously applied preferential illumination of ChR2-expressing BLA terminals in the CeL with a 20 Hz, 5 ms light train for 2 s (mean over 6 sweeps per cell). For the experiments comparing the broad illumination of the BLA terminal field centered in the CeM to selective illumination of BLA-CeL terminals, these conditions were performed in repeated alternation in the same CeM cells (n=7).
To verify that terminal inhibition did not alter somatic spiking, animals were injected with AAV5-CaMKIIα-eNpHR3.0-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Slice preparation was the same as above. Whole-cell patch-clamp recordings were performed in BLA neurons and were allowed to fill for approximately 30 minutes. Light was delivered through a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). Whole-cell patch-clamp recordings were performed on BLA neurons. Series resistance of the pipettes was usually 10-20 MOhms. Yellow light pulses were elicited using a XCite halogen light source (EXPO, Mississauga, Ontario) with a 589/24 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). After patching, an unrestricted light spot (˜425-450 microns in diameter) was placed over the BLA soma and a 1 s pulse was applied. Cells were excluded if the current recorded was under 600 pA of hyperpolarizing current and the axon did not travel over ˜300 μm towards the CeL nucleus. The light spot was then restricted to −125 in diameter. On and off axon voltage clamp recordings were taken with a 1 s pulse of light. For the current clamp recordings, action potentials were generated by applying 250 pA of current to the cell soma through the patch pipette.
To demonstrate that selective illumination of eNpHR3.0-expressing BLA terminals reduced the probability of spontaneous vesicle release, animals were injected with AAV5-CaMKIIα-eNpHR3.0-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Slice preparation was the same as above. Whole-cell patch-clamp recordings were performed in central lateral neurons. Light was delivered through a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). Series resistance of the pipettes was usually 10-20 MOhms Yellow light pulses were elicited using a XCite halogen light source (EXPO, Mississauga, Ontario) with a 589/24 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). The light spot was restricted to ˜125 μm in diameter. Carbachol was added to the bath at a concentration of 20 μM. After sEPSC activity increased in the CeL neuron, light pulses were applied ranging in times from 5 s to 30 s.
To demonstrate that selective illumination of eNpHR3.0-expressing BLA terminals could reduce the probability of vesicle release evoked by electrical stimulation, animals were injected with AAV5-CaMKIIα-eNpHR3.0-EYFP at 4 weeks of age, and were sacrificed for acute slice preparation 4-6 weeks to allow for viral expression. Slice preparation was the same as above. A bipolar concentric stimulation probe (FHC, Bowdoin Me.) was placed in the BLA. Whole-cell patch-clamp recordings were performed in CeL neurons. Light was delivered through a 40×/0.8 NA LUMPlanFL/IR Objective (Olympus, Center Valley Pa.). Series resistance of the pipettes was usually 10-20 MOhms. Amber light pulses over the central lateral cell were elicited using a XCite halogen light source (EXPO, Mississauga, Ontario) with a 589/24 filter at 6.5 mW/mm 2 coupled to a shutter (Uniblitz, Rochester N.Y.). The light spot was restricted to ˜125 μm in diameter. Electrical pulses were delivered for 40 seconds and light was delivered starting at 10 seconds and shut off at 30 seconds in the middle.
For the anatomical tracing experiments, neurons were excluded when the traced axons were observed to be severed and all BLA neurons included in the anatomical assay ( FIG. 5 a - i ) showed spiking patterns typical of BLA pyramidal neurons 18 upon a current step.
Slice Immunohistochemistry:
Anesthetized mice were transcardially perfused with ice-cold 4% paraformaldehyde (PFA) in PBS (pH 7.4) 100-110 min after termination of in vivo light stimulation. Brains were fixed overnight in 4% PFA and then equilibrated in 30% sucrose in PBS. 40 μm-thick coronal sections were cut on a freezing microtome and stored in cryoprotectant at 4° C. until processed for immunohistochemistry. Free-floating sections were washed in PBS and then incubated for 30 min in 0.3% T×100 and 3% normal donkey serum (NDS). Primary antibody incubations were performed overnight at 4° C. in 3% NDS/PBS (rabbit anti-c-fos 1:500, Calbiochem, La Jolla, Calif.; mouse anti-CaMKII 1:500, Abcam, Cambridge, Mass.). Sections were then washed and incubated with secondary antibodies (1:1000) conjugated to Cy3 or Cy5 (Jackson Laboratories, West Grove, Pa.) for 3 hrs at room temperature. Following a 20 min incubation with DAPI (1:50,000) sections were washed and mounted on microscope slides with PVD-DABCO.
Confocal Microscopy and Analysis:
Confocal fluorescence images were acquired on a Leica TCS SP5 scanning laser microscope using a 20×/0.70NA or a 40×/1.25NA oil immersion objective. Serial stack images covering a depth of 10 μm through multiple sections were acquired using equivalent settings. The Volocity image analysis software (Improvision/PerkinElmer, Waltham, Mass.) calculated the number of c-fos positive cells per field by thresholding c-fos immunoreactivity above background levels and using the DAPI staining to delineate nuclei. All imaging and analysis was performed blind to the experimental conditions.
Statistics:
For behavioral experiments and the ex vivo electrophysiology data, binary comparisons were tested using nonparametric bootstrapped t-tests (paired or unpaired where appropriate) 5 , while hypotheses involving more than two group means were tested using linear contrasts (using the “boot” and “lme4” packages in R 6 , respectively); the latter were formulated as contrasts between coefficients of a linear mixed-effects model (a “two-way repeated-measures ANOVA”) with the fixed effects being the genetic or pharmacological manipulation and the light treatment (on or off). All hypothesis tests were specified a priori. Subjects were modeled as a random effects. For c-fos quantification comparisons, we used a one-way ANOVA followed by Tukey's multiple comparisons test.
Plots of the data clearly show a relationship between observation mean and observation variance (that is, they are heteroskedastic; see for example, FIG. 3 e and FIG. 5 j ). We found that a standard square-root transformation corrected this well. Additionally, eNpHR3.0 elevated plus maze (EPM) data required detrending by a linear fit over time to account for a decrease in exploration behavior over time. As is standard for a two-way linear mixed effects model (also known as a two-way repeated-measures ANOVA), we model (the square-root corrected value of) the kth observation in the ijth cell (y ijk ) as
√{square root over ( y ijk )}=μ+ c i +t j +( c:t ) ij +b j +e ijk (1)
where
μ is the grand mean across all cells (where the ijth “cell” in the collection of observations corresponding to the ith condition and jth treatment)
c i is a fixed effect due to the ith animal condition across treatments (for example, a genetic manipulation)
t j is a fixed effect due to the jth treatment across conditions (for example, light on or light off)
(c:t) ij is a fixed effect due to the interaction of the ith condition and jth treatment in the ijth cell
b j is a random effect corresponding to animals being used across treatments, and
e ijk is an independent and identically distributed (i.i.d.) random normal disturbance in the ijkth observation with mean 0 and variance σ 2 , and independent of b j for all j
Collecting the fixed effects into a 2-way analysis of variance (ANOVA) design matrix X R nxp , dummy coding the random effects in a sparse matrix Z R nxq , and letting {tilde over (y)}=√{square root over (y)} we can express the model in matrix form as
{tilde over (y)}=Xβ+Zb+e (2)
where {tilde over (y)}ε n , bε q , and e ε n are observations of random variables {tilde over (y)}, B, and ε respectively and our model assumes
B˜N (0, σ 2 Σ) ε˜ N (0, σ 2 I ),ε⊥ B ( {tilde over (y)}|B=b )˜ N ( Xβ+Zb, σ 2 I )
where N (μ, Σ) denotes the multivariate Gaussian distribution with mean vector μ and variance-covariance matrix Σ, and ⊥ indicates that two variables are independent. To estimate the coefficient vectors β R p , b R q , and the variance parameter σ and sparse (block-diagonal) relative variance-covariance matrix Σ R qxq , we use the lme4 package in R written by Douglas Bates and Martin Maechler, which first finds a linear change of coordinates that “spheres” the random effects and then finds the maximum likelihood estimates for β, σ, and Σ using penalized iteratively reweighted least-squares, exploiting the sparsity of the random effects matrix to speed computation. For more details see the documentation accompanying the package in the lme4 repository at http://www.r-project.org/.
To solve for the maximum likelihood estimates, the design matrix X in equation 2 must be of full column rank. It is well known that this is not the case for a full factorial design matrix with an intercept (as in equation 1), and thus linear combinations (“contrasts”) must be used to define the columns of X in order for the fixed-effect coefficients to be estimable. As our designs are balanced (or nearly balanced), we used orthogonal (or nearly orthogonal) Helmert contrasts between the coefficients associated with light on as compared to light off conditions, terminal stimulation as compared to control conditions, and so on, as reported in the main text. Such contrasts allowed us to compare pooled data (e.g., from several sequential light on vs. light off conditions) against each other within a repeated-measures design—yielding improved parameter estimation and test power while accounting for within-animal correlations.
Results
BLA cells have promiscuous projections throughout the brain, including to the bed nucleus of the stria terminalis (BNST), nucleus accumbens, hippocampus and cortex 38, 43 . To test whether BLA-CeL synapses could be causally involved in anxiety, it was therefore necessary to develop a method to selectively control BLA terminals in the CeL, without directly affecting other BLA projections. To preferentially target BLA-CeL synapses, we restricted opsin gene expression to BLA glutamatergic projection neurons and restricted light delivery to the CeA. Control of BLA glutamatergic projection neurons was achieved with an adeno-associated virus (AAV5) vector carrying light-activated optogenetic control genes under the control of a CaMKIIα promoter; within the BLA, CaMKIIα is only expressed in glutamatergic pyramidal neurons, not in local interneurons or intercalated cells 48 . To preferentially deliver light to the CeA projection, virus was delivered unilaterally into the BLA under stereotaxic guidance ( FIGS. 7 and 8 ) along with implantation of a beveled guide cannula over the CeL to prevent light delivery to the BLA and allow selective illumination of the CeA. Geometric and functional properties of the resulting light distribution were quantified both in vitro and in vivo, with in vivo electrophysiological recordings to determine light power parameters for selective control of BLA terminals but not BLA cell bodies ( FIG. 9 ).
To test the hypothesis that the BLA-CeA pathway could implement an endogenous mechanism for anxiolysis, we probed freely-moving mice under projection-specific optogenetic control in two distinct and well-validated anxiety assays: the elevated plus maze and the open field test ( FIG. 3 a - f ). Mice display anxiety-related behaviors when exposed to open or exposed spaces, therefore increased time spent in the exposed arms of the elevated plus maze or in the center of the open field chamber indicates reduced anxiety 49, 50 . To test for both induction and reversal of relevant behaviors, we first exposed mice to the elevated plus maze for three 5-min epochs, in which light was delivered during the second epoch only.
To determine whether the anxiolytic effect we observed would be specific to activation of BLA terminals in the CeA, and not BLA cells in general, we compared mice receiving projection-specific control (in the ChR2:BLA-CeA group; FIG. 3 a ) to both a negative control group receiving transduction with a control virus given the same pattern of illumination (EYFP:BLA-CeA) and a positive control group transduced with the AAV-CaMKIIα-ChR2-EYFP virus in the BLA with a fiber implanted directly over the BLA (ChR2:BLA Somata). For this group (ChR2:BLA Somata), light stimulation did not elicit the anxiolysis observed in the ChR2:BLA-CeA group ( FIGS. 3 b and c ); indeed, the ChR2:BLA-CeA group spent significantly more time in open arms (t(42)=8.312; p<0.00001; FIG. 3 b,c ) during light-induced activation of BLA terminals in the CeA, in comparison to controls (EYFP:BLA-CeA and ChR2:BLA Somata groups). The ChR2:BLA-CeA mice also showed an increase in the probability of entering an open arm rather than a closed arm, from the choice point of the center of the maze ( FIG. 3 c inset), indicating an increased probability of selecting the normally anxiogenic environment.
We also probed mice on the open field arena for six 3-minute epochs, again testing for reversibility by alternating between no light (off) and light stimulation (on) conditions. Experimental (ChR2:BLA-CeA) mice displayed an immediate, robust, and reversible light-induced anxiolytic response as measured by the time in center of the open field chamber ( FIGS. 3 d and e ), while mice in the EYFP:BLA-CeA and ChR2:BLA Somata groups did not ( FIG. 3 e ). Light stimulation did not significantly alter locomotor activity ( FIG. 3 f ). While there was no detectable difference among groups in the off conditions, there was a significant increase in center time of the open field spent by mice in the ChR2:BLA-CeA group relative to the EYFP:BLA-CeA or ChR2:BLA Somata groups during the on conditions (t(105)=4.96178; p<0.0001 for each contrast). We concluded that selective stimulation of BLA projections to the CeA, but not BLA somata, produces an acute, rapidly reversible anxiolytic effect, supporting the hypothesis that the BLA-CeL-CeM pathway could represent a native microcircuit for anxiety control.
We next investigated the physiological basis of this light-induced anxiolytic effect. Glutamatergic neurons in the BLA send robust excitatory projections to CeL neurons as well as to CeM neurons 38 ; however, not only are the CeM synapses distant from the light source ( FIG. 8 ), but also any residual direct excitation of these CeM neurons would be expected to result in an anxiogenic, rather than an anxiolytic, effect 12 . However, CeL neurons exert strong inhibition onto these brainstem-projecting CeM output neurons 32, 35, 40 , and we therefore hypothesized that illumination of BLA terminals in the CeA could activate BLA-CeL neurons and thereby elicit feed-forward inhibition onto CeM neurons and implement the observed anxiolytic phenomenon.
To confirm the operation of this optogenetically-defined projection, we undertook in vivo experiments, with light delivery protocols matched to those delivered in the behavioral experiments, and activity-dependent immediate early gene (c-fos) expression analysis as the readout to verify the pattern of neuronal activation ( FIG. 3 g - k ). Under blinded conditions, we quantified the proportion of neurons in the BLA, CeL and CeM ( FIG. 3 i - k ) for ChR2:BLA-CeA, EYFP:BLA-CeA and ChR2:BLA Somata groups that expressed EYFP or showed c-fos immunoreactivity. Virus expression under the CaMKIIα promoter in the BLA targeted glutamatergic neurons 47 , and we did not observe EYFP expression in local interneurons nor intercalated cells ( FIG. 10 ). No significant differences among groups were detected in the proportion of EYFP-positive cells within each region ( FIG. 3 g - k ), but we found a significantly higher proportion of c-fos positive BLA cells in the ChR2:BLA Somata group, relative to ChR2:BLA-CeA or EYFP:BLA-CeA groups ( FIG. 3 i ; p<0.01 and p<0.05, respectively). There was no detectable difference in c-fos between the ChR2:BLA-CeA and EYFP:BLA-CeA groups, indicating that the beveled cannula shielding effectively prevented direct illumination to BLA cell bodies. A significantly higher proportion of CeL neurons expressed c-fos in the ChR2:BLA-CeA group relative to the EYFP:BLA-CeA group (p<0.05), but not the ChR2:BLA Somata group ( FIG. 3 j ). Thus, selective illumination of BLA terminals expressing ChR2 in the CeA led to preferential activation of CeL neurons, without activating BLA somata. In the CeM, we found twice as many c-fos positive neurons (relative to total neurons) in the ChR2:BLA Somata group than in the ChR2:BLA-CeA ( FIG. 3 k ), consistent with anatomical projections, as LA neurons selectively innervate CeL neurons, while neurons in the BL and BM nuclei of the amygdala have monosynaptic projections to both the CeL and the CeM 38, 43, 51 . Together, these data reveal that the in vivo illumination that triggers an acute anxiolytic behavioral phenotype implements selective illumination of BLA-CeL synapses without activating BLA cell bodies.
To test the hypothesis that selective illumination of BLA terminals in the CeL induces feed-forward inhibition of CeM output neurons, we combined whole-cell patch-clamp recording with live two-photon imaging to visualize the microcircuit while simultaneously probing the functional relationships among these cells during projection-specific optogenetic control ( FIG. 4 a - f ). While the light-stimulation parameters used in vivo were delivered via a fiber optic and the parameters used in our ex vivo experiments were delivered onto acute slices, we matched the light power density at our target location ˜6 mW/mm 2 . A two-photon image of the BLA-CeL-CeM circuit is shown in FIG. 4 a , with all three cells imaged from the same slice ( FIG. 4 a ). The BLA neuron expressing ChR2-EYFP showed robust, high-fidelity spiking to direct illumination with 20 Hz, 5 ms pulses of 473 nm light ( FIG. 4 b ). A representative trace from a CeL neuron, recorded during illumination of the terminal field of BLA neurons expressing ChR2-EYFP, demonstrates the typical excitatory responses seen in CeL ( FIG. 4 c ), with population summaries revealing that spiking fidelity was steady throughout the 40-pulse light train and that responding cells include both weakly and strongly-excited CeL cells (n=16; FIG. 4 c ). To test whether illumination of BLA-CeL synapses would be functionally significant at the level of blocking spiking in CeM cells due to the robust feed-forward inhibition from CeL neurons, we recorded from CeM neurons while selectively illuminating BLA-CeL synapses ( FIG. 4 d ). Indeed, we observed potent spiking inhibition (F 2,11 =15.35, p=0.0044) in the CeM due to light stimulation of BLA terminals in the CeL ( FIG. 4 d ; spikes per second before (49±9.0), during (1.5±0.87), and after (33±8.4) illumination; mean±s.e.m). Next, FIG. 4 e shows CeM responses recorded during illumination of the terminal field of BLA neurons in the CeM expressing ChR2-EYFP, and the combined excitatory and inhibitory input. Population summaries from voltage-clamp recordings indicated that latencies of EPSCs were shorter than those of the disynaptic IPSCs, as expected, and that the mean IPSC amplitude was greater than mean EPSC amplitude (recorded at 0 and −70 mV, respectively; FIG. 4 e ). Importantly, the very same CeM neurons (n=7) yielded net excitation with broad illumination of BLA inputs to the CeM ( FIG. 4 e ), but displayed net inhibition with selective illumination of BLA inputs to the CeL ( FIG. 4 f ) in a repeatable fashion with alternation between sites. This demonstrates that the balance of direct and indirect inputs from the BLA to the CeM can modulate CeM output. Together, these data reveal a structurally- and functionally-identified physiological microcircuit, whereby selective illumination of BLA terminals in the CeA activates BLA-CeL synapses, thus increasing feed-forward inhibition from CeL neurons onto the brainstem-projecting CeM neurons.
To further elucidate the amygdalar microcircuits underlying this anxiolytic effect, we carefully dissected the anatomical and functional properties governing this phenomenon. While some efforts to map the projections of BLA collaterals in the CeA have been made in the rat, we empirically tested whether overlapping or distinct populations of BLA neurons projected to the CeL and CeM ( FIG. 5 a,b ). A noteworthy caveat is that we visualized these neurons in ˜350 um thick coronal sections and while every attempt was made to exclude neurons in which the axons were severed, we cannot exclude the possibility that this occurred nor can we deny that this induced some sampling bias for BLA neurons closer to the CeA. FIG. 5 a summarizes the anatomical projections of the BLA neurons sampled (n=18) and shows that the 44% of neurons projected to the CeL alone and 17% projected to the CeM alone. However, a minority of BLA cells (n=1; 6%), projected to both the CeL and the CeM, one of which sent separate collaterals to the CeL and CeM and one of which sent a collateral that sent branches to the CeL and CeM. FIG. 5 b shows the 2-photon image of each cell sampled, all of which showed spiking patterns typical of BLA pyramidal neurons upon a current step.
Next, as our c-fos assays suggested that illumination of BLA terminals in the CeL were sufficient to excite CeL neurons, but not BLA neurons themselves, we sought to confirm this hypothesis with whole-cell recordings. With electrical stimulation, depolarization of axon terminals leads to antidromic spiking at the cell soma. However, there has been evidence that optogenetically-induced depolarization functions via a distinct mechanism. To evaluate the properties of optogenetically-induced terminal stimulation in this amygdalar microcircuit, we recorded from BLA pyramidal neurons expressing ChR2 and moved a light spot (˜120 μm in diameter) in 100 μm steps from the cell soma, both in a direction over a visually-identified axon collateral and in a direction where there was no axon ( FIG. 5 c ). The spike fidelity of the BLA neuron given a 20 Hz train of light at each distance from the soma is summarized in FIG. 5 d , while the depolarizing current is summarized in FIG. 5 e . In all preparations, we confirmed that the light stimulation parameters used were sufficient to elicit high-fidelity spiking at the BLA cell soma ( FIG. 5 f ) and reliable vesicle release at BLA terminals as shown by recordings from a postsynaptic CeL neuron ( FIG. 5 g ; FIG. 15 ). In contrast, when recording from the same BLA neurons with the light spot 300 um away from the cell soma we did not observe reliable action potential induction, regardless of whether we were over an axon ( FIG. 5 h ) or not ( FIG. 5 i ). This absence of antidromic spiking was observed even upon bath application of GABA and AMPA receptor antagonists (n=7), thus excluding the possible contribution of local inhibitory constraints. While we demonstrate that optogenetically-induced vesicle release can occur in the absence of antidromic stimulation in BLA pyramidal neurons, it is possible that at antidromic stimulation could be achieved with greater light power density than we used here (˜6 mW/mm 2 ) Thusfar, we have demonstrated that the populations of BLA neurons projecting to the CeL and the CeM are largely distinct and that illumination of BLA-CeL synapses induces vesicle release and CeL excitation without strong activation of BLA somata themselves.
Finally, we further explored the mechanism with in vivo pharmacological analysis in the setting of projection-specific optogenetic control. To determine whether the anxiolytic effect we observed could be due to the selective activation of BLA-CeL synapses alone, and not BLA fibers passing through the CeA, nor back-propagation of action potentials to BLA cell bodies which then would innervate all BLA projection target regions, we tested whether local glutamate receptor antagonism would attenuate light-induced anxiolytic effects. This question is of substantial interest since lesions in the CeA that alter anxiety are confounded by the likelihood of ablation of BLA projections to the BNST which pass through CeA 6 . We unilaterally transduced BLA neurons with AAV-CaMKIIα-ChR2-EYFP and implanted beveled cannulae to implement selective illumination of BLA terminals in the CeA as before (n=8; FIG. 8 ), and tested mice on the elevated plus maze and open field test. In this case, however, we infused either the glutamate antagonists NBQX and AP5 using the optical fiber guide cannula, or saline control on different trials in the same animals, with trials counter-balanced for order. Confirming a local synaptic mechanism rather than control of fibers of passage, for the same mice and light stimulation parameters, local glutamate receptor antagonism in the CeA abolished light-induced reductions in anxiety on both the elevated plus maze ( FIG. 5 k ) and the open field test ( FIG. 5 j ). Importantly, in control experiments, drug treatment did not impair locomotor activity ( FIG. 11 ), and in acute slices time-locked light-evoked excitatory responses were abolished upon bath application of NBQX and AP5 ( FIG. 12 ). Together these data indicate that the light-induced anxiolytic effects we observed were caused by the activation of BLA-CeL synapses, and not attributable to BLA projections to distal targets passing through the CeA.
In a final series of experiments, to determine if endogenous anxiety-reducing processes could be blocked by selectively inhibiting this pathway, we tested whether the selective inhibition of these optogenetically defined synapses could reversibly increase anxiety. We performed bilateral viral transduction of either eNpHR3.0, a light-activated chloride pump which hyperpolarizes neuronal membranes upon illumination with amber light 25 , or EYFP alone, both under the CaMKIIα promoter in the BLA, and implanted bilateral beveled guide cannulae to allow selective illumination of BLA terminals in the CeA ( FIG. 6 a ; FIG. 13 ). eNpHR3.0 expression was restricted to glutamatergic CaMKIIα-positive neurons in the BLA ( FIG. 6 b ). The eNpHR3.0:BLA-CeA group only showed significantly elevated levels of c-fos expression, relative to the EYFP:BLA-CeA bil and eNpHR 3.0:Soma groups, in the CeM (p<0.05; FIG. 6 c - e ), consistent with the hypothesis that selective inhibition of BLA terminals in the CeA suppresses feed-forward inhibition from CeL neurons to CeM neurons, thus increasing CeM excitability and the downstream processes leading to increased anxiety phenotypes. Importantly, inhibition of BLA somata did not induce an anxiogenic response, likely due to the simultaneous decrease in direct BLA-CeM excitatory input. We also found that the eNpHR3.0:BLA-CeA group showed a significant reduction in open arm time and probability of open arm entry on the elevated plus maze during light-on epochs, but not light-off epochs, relative to the EYFP and Soma groups ( FIG. 6 f,g ), without altering locomotor activity ( FIG. 16 ). The eNpHR3.0:BLA-CeA group also showed a significant reduction in center time upon illumination with 594 nm light, relative to the EYFP and Soma groups (statistics, p=0.002; FIG. 6 h,i ) Finally, we also demonstrate that selective illumination of eNpHR3.0-expressing axon terminals can reduce the probability of both spontaneously occurring ( FIG. 6 j - l ) and evoked ( FIG. 6 m - p ) vesicle release, without preventing spiking at the cell soma ( FIG. 14 ). These data demonstrate that selective inhibition of BLA terminals in the CeA induces an acute increase in anxiety-like behaviors.
CONCLUSIONS
In these experiments, we have identified the BLA-CeL pathway as an endogenous neural substrate for bidirectionally modulating the unconditioned expression of anxiety. While we identify the BLA-CeL pathway as the critical substrate rather than BLA fibers passing through the CeL, it is likely that other downstream circuits, such as CeA projections to the BNST play an important role in the expression of anxiety or anxiety-related behaviors 4, 6, 13 . Indeed, our findings may support the notion that corticotrophin releasing hormone (CRH) networks in the BNST can be critically involved in modulating anxiety-related behaviors 6, 52 , as the CeL is a primary source of CRH for the BNST 53 .
Other neurotransmitters and neuromodulators may modulate or gate effects on distributed neural circuits, including serotonin 54, 55 , dopamine 56 , acetylcholine 57 , glycine 58 , GABA 13 and CRH 59 . The neural circuitry converging to and diverging from this pathway will provide many opportunities for modulatory control, as parallel or downstream circuits of the BLA-CeL synapse likely contribute to modulate the expression of anxiety phenotypes 6, 56 . Moreover, upstream of the amygdala, this microcircuit is well-positioned to be recruited by top-down cortical control from regions important for processing fear and anxiety, including the prelimbic, infralimbic and insular cortices that provide robust innervation to the BLA and CeL. 4, 13, 23, 60 .
Our examination of the BLA anatomy suggests that the populations of BLA neurons projecting to CeL and CeM neurons are largely non-overlapping. In natural states, the CeL-projecting BLA neurons may excite CeM-projecting BLA neurons in a microcircuit homeostatic mechanism. This may also represent a potential mechanism underlying anxiety disorders, when there are synaptic changes that skew the balance of the circuit to allow uninhibited CeM activation.
Together, the data presented here support identification of the BLA-CeL synapse as a critical circuit element both necessary and sufficient for the expression of endogenous anxiolysis in the mammalian brain, providing a novel source of insight into anxiety as well as a new kind of treatment target, and demonstrate the importance of resolving specific projections in the study of neural circuit function relevant to psychiatric disease.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, the descriptions and examples should not be construed as limiting the scope of the invention.
All references, publications, and patent applications disclosed herein are hereby incorporated by reference in their entirety.
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BACKGROUND OF THE INVENTION
This is a division of application Ser. No. 569,276, filed Apr. 14, 1975, now U.S. Pat. No. 3,965,635.
The art of brick making is thousands of years old and an integral part of the process is the firing. Since the Second World War many brick companies have used natural gas as a fuel for firing the brick. As is well known, there is now a shortage of natural gas and as a consequence, modified procedures are necessary.
Additionally, a need has arisen in modern construction for eliminating or minimizing the great expense of labor in brick laying. In response to the need, prefabricated panels of brick work have been provided and the panels are suitable for unit assembly to form interior and exterior walls of buildings. Unfortunately, the mass of the typical prefabricated brick panel is such that rather heavy machinery is required for moving the panels from one place to another.
It is an object of this invention to provide a prefabricated building panel and a specific process for making the panel such that the cost of the brick to make the panel and the panel itself are less expensive, the panel is of lighter weight and the resulting panel may be structurally more or less rigid than conventional brick and mortar walls, depending on whether the wall is to be load bearing or merely a curtain wall.
BRIEF DESCRIPTION OF THE INVENTION
The panel itself includes fired ceramic or brick or cementitious facing units or the like. For convenience the facing units will hereinafter be referred to as "bricks" but the word is intended to include all such units. As is well known to those having ordinary skill in the brick making art, the firing time for a given brick is geometrically proportional to the shortest dimension between exposed faces. Obviously, a one-quarter brick requires much less firing time than a conventional size brick with the resultant savings in fuel costs.
The facing bricks are deposited on a horizontal mold form which includes indicia thereon to indicate proper placement of the bricks. It is intended that the final product should look like a conventional brick wall laid by hand; thus, the bricks are all spaced apart. To enhance the authentic appearance of the brickwork, some suitable means is provided to fill the spaces between the bricks near their downward face, thereby preventing any portion of subsequently deposited cementitious layers from migrating to the front brick face.
Mortar composition is mixed with fibers (glass, steel, nylon, etc.) and is used to fill the spaces between the bricks and provide a first layer on the upwardly facing back portion of the bricks. A lattice work may be provided of criss-crossing beams and shafts welded or otherwise joined at their intersections and of appropriate cross-section for minimizing flexure. The lattice work is pushed into the first cementitious layer at the backs of the bricks while the grout is still soft. Prior to the deposition of mortar-fiber composition, an appropriate adhesive may be sprayed or otherwise applied over the exposed surfaces of the bricks and between the bricks to minimize migration of mortar to the front, enhance the bonding of the cementitious mixture, and to provide a barrier in the spaces between the bricks to at least partially block exposed fibers from view from the front face of the panel. Next, a homogeneous aqueous mixture of cement and fibers is sprayed over the lattice work, first cementitious layer and the exposed brick to bond the lattice work to the bricks. The fibrous nature of the cementitious layers will anchor the lattice work in place when the second layer is properly bonded to the first layer.
If desired, a variety of insulation materials may be applied to the panel by depositing the insulation material in the cavities formed between the shafts and beams of the lattice work. A preferred insulation material which is effective both for sound as well as heat insulation is foamed polyurethane which is foamed in situ to a depth approximating the height of the lattice work. It will be recognized that if a properly rigid insulation layer can be properly bonded to the brick work the lattice work might be eliminated. Further, various insulation materials may be used instead of foamed polyurethane as will be understood by technicians in the field.
It may be desired to put a finish coat of some material on the back of the insulation material for aesthetic purposes. Another spray coat of the fibrous mixture may be applied if desired; and in view of the properties of the fibrous material observed, it is clear that such a spray coat of said glass fiber material would give some added strength to the panel although such added strength would be unnecessary for any conventional purposes.
The reasons for increased strength and flexibility of the fibrous mixture as compared to a conventional layer of concrete is explained in a January, 1962 article entitled Two-Phase Materials by Games Slayter published in Scientific America, pages 124-134; and to the extent necessary for a full understanding of this invention, the article is incorporated herein by reference.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a horizontal mold on which are to be deposited facing bricks suitable for the manufacture of a prefabricated building panel;
FIG. 2 is a fragmentary sectional view of a portion of the mold form of FIG. 1 taken along line 2--2;
FIG. 3 is a perspective view of a thin brick used in the manufacture of the prefabricated panel of this invention.
FIG. 4 is a fragmentary sectional view similar to FIG. 2 but with the facing brick and layer of mortar-fiber mixture deposited thereon;
FIG. 5 shows one modification of U-shaped metallic beams and shafts bonded together to form a lattice work which is subsequently to be joined to the facing brick of FIG. 4;
FIG. 6 is an alternative structure of lattice work which may be substituted for the structure of FIG. 5;
FIG. 7 is a fragmentary sectional view similar to FIG. 4 but with the lattice work bonded to the facing brick and with the insulation and facing coat applied; and
FIG. 8 is a perspective view of the front of the prefabricated building panel of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention will be described with reference to glass fibers and it is recognized that special treatment of the fibers may be necessary to prevent their chemical deterioration or agglomeration during mixing. Such problems and suggested solutions are a part of U.S. Pat. Nos. 2,738,285; 2,793,130; 3,062,670; 3,147,127; and 3,716,386; and to the extent necessary for a full understanding of this invention, said patents are incorporated by reference. Uses of steel and other kinds of fibers in concrete and the like are described in U.S. Pat. Nos. 3,429,094; 3,500,728, 3,650,785 and 3,808,085; and to the extent necessary for a full understanding of this invention, they are also incorporated by reference.
For convenience, the invention herein will be described by the process of making the building panel of this invention.
With reference specifically to FIG. 1, a mold form 10 is first laid horizontally on some supporting structure adequate to support the weight of the building panel after it is constructed. While there are a number of possible types of molds which might be used for this invention without departing from the spirit thereof, for convenience a plastic shell is illustrated including longitudinal ridges 12 and transverse ridges 14 to serve as indicia to indicate where the facing bricks 16, as illustrated in FIG. 3, should be located and as a means to fill the spaces between the placed bricks to minimize migration of grout to the front 18 of the panel.
It will be observed that the brick 16 illustrated in FIG. 3 is thin relative to a conventional brick. In fact, it is only about 1/8 - 1 inch in thickness. Bricks 16 are placed in the cavities between ridges 12 and 14 (or between other indicia means indicating proper brick placement). In the absence of ridges 12 and 14, some other means should be provided to minimize the migration of grout to the front fact 18 of the bricks. Rods could be laid between the bricks or any other suitable means could be used. However, in the illustrated embodiment the ridges 12 and 14 are slightly tapered and serve that purpose. Therefore, when a layer of mortar 20 (actually an aqueous mixture of cement and glass fibers) is deposited by spraying or otherwise depositing over the bricks, after the mold 10 is removed and the exposed faces 18 of the bricks are inspected they will appear conventional with the hardened concrete slightly recessed from the brick face. Because of the minimal thickness of the bricks 16, the mortar layer 20 will be recessed from the exposed face of the bricks at most about one eighth of an inch. As with any cement operation, it is desirable to lightly spray the brick surface with water before a cement mixture is deposited to prevent absorption of water from the cement mix. Other sequential depositions of cement mixes may be preceded by a water spray as needed. Alternatively, an adhesive spray may be used.
At this point in time, the panel with the single layer of mortar and glass fibers may be used as a curtain wall without any further treatment. Such a wall would weigh only about 5-6 lbs./ft 2 but it would be rather flexible. The fact that the mixture of cement and glass fibers, properly applied, is capable of bonding the bricks together is significant because the back surfaces are not necessarily especially grooved or mechanically roughened to enhance the bonding, although some roughening or grooving would be acceptable. Note also that the brick panel will "flex" without breaking at the mortar line between bricks which is contrary to conventional concrete layers. The flexing is due to the tension strength of the glass fibers.
Assuming a desire for a load bearing or more rigid panel, the next step in the procedure is the laying of the lattice work 22 over the bricks and cementitious layer. It should be emphasized that no particular configuration of lattice work is preferred over another in terms of effectiveness except that the structural forms are required to have greater rigidity than merely round rods welded together at their juncture. Rigidity must be achieved by use of the lattice work because of the relatively thin wall formed by the thin bricks. The flexing of the prefabricated wall should be kept at a minimum where such is detrimental to its intended use; and as a consequence, it is necessary that the structures forming the lattice work be more rigid than a round rod (which, in combination with the thin wall, is inadequate).
FIGS. 5 and 6 show two modifications which are merely illustrative but are effective for the purposes intended.
FIG. 5 illustrates beams 24 of U-shaped configuration intersected by U-shaped shafts 26. In this case the beams and shafts are metallic and are welded together at their juncture 28. It is clear that other materials and shapes could be used but for purposes of convenience only the U-shape of FIG. 5 and V-shape of FIG. 6 have been illustrated.
FIG. 6 illustrates beams 30 and shafts 32 and functionally they are equivalent of the beams and shafts 26 and 28, respectively, of FIG. 5.
Observing FIG. 7, the lattice work 22 is laid on the surface of the mortar 20 and preferably pressed therein to provide an enhanced anchor between the lattice work and the mortar layer. On pressing the lattice work inward, small grooves 34 will be formed and a bulge of the mortar at 36 will extend upwardly and perhaps slightly over the portion of the lattice work pressed into the mortar.
Next a mixture of cementitious material is sprayed as a layer 38 over the exposed surfaces of the lattice work, mortar, and any portion of the bricks remaining exposed. The ingredients of the sprayed cementitious mixture are the same as the first mortar layer 20 and they are significant as the solidified mixture provides some unique structural properties. The ingredients are roughly as follows:
______________________________________ Ingredients Amounts______________________________________Type 1 Portland cement 58.5 poundsHydrated lime 11.25 poundsCalcium stearate 0.75 poundsGlass fiber (about 1/2 inch length) 3 poundsWater 36 pounds 109.50 pounds______________________________________
The ingredients come premixed and are sold under the trademark BlocBond (a trademark of Owens-Corning Fiberglass Corporation). It is obvious that a range of modified mixtures could be used but the indicated ingredients are preferred with the weight ratio of cement to glass fibers being about 20 to 1. The glass fibers in this instance provide a unique feature in that with the ingredients enumerated above, the cementitious mixture bonds to the glass fibers as well as to the first mortar layer 20 and the lattice work. The glass fibers tend to strengthen the mass in tension and tend to bridge gaps which may exist in the deposited layer 38. It is important that the length of the glass fibers not be substantially greater than 1/2 inch because when the fibers are too long they may tend to clog the spray nozzle 39. It is clear that the mixture could be deposited in a number of ways over the lattice work including troweling, brushing, etc., but equally clear is that spraying will be far superior in terms of time spent in depositing the second cementitious layer 38.
The preferred mixing or blending procedure for the ingredients which are to be sprayed on the backs of the thin bricks is as follows:
(a) The dry cement, lime and calcium stearate are blended in a conventional cement mixing apparatus for 15-30 seconds and the fibers are added slowly to insure even distribution;
(b) Water is added to a drum-type mortar mixer (35 to 38 lbs.);
(c) With the mixer running, about half the dry blend is dumped into the water and mixed for about 15 seconds;
(d) The remainder of the dry blend is slowly added and a final mix for 60 to 90 seconds will insure a smooth uniform consistency.
Excessive mixing tends to cause the fibers to agglomerate with resulting lumps. Lumps preclude spraying, and while deposition of the lumpy mixture by outer means is possible, the resulting layer will not have a uniform consistency or surface.
The thickness of the layer 38 should not be greater than about 1/8 to 1/4 inch for maximum efficiency. One-eighth inch thickness will give strength and bonding characteristics to the extent necessary for proper operation of this invention. A greater thickness will not be particularly detrimental to the structure but it should be recognized that a greater thickness will not add anything structurally to the panel.
The lattice work forms another useful function. It should be considered desirable to insulate the wall panel, as for example in an office building where the wall panel is to face outward and the lattice work will be near the inside surface. In such an instance, insulating material 40 may be placed in the cavities between the beams and shafts forming the lattice work. A number of different kinds of insulation are suitable but the preferred insulation is polyurethane foamed in situ. In FIG. 7, the foamed polyurethane is deposited to a depth approximately equal to the height of the lattice work.
If desired, an inside facing coat 42 of some sort may be applied over the foamed polyurethane 40. It is recognized that the facing coat 42 could be another spray coat of the cement-fiberglass mixture, in which case it would add a certain amount of strength to the structure but under any conceivable normal circumstances such added strength is not required.
After the materials have all cured, the mold 10 is removed and the prefabricated panel 44 illustrated in FIG. 8 is suitable for use as an interior or exterior wall in conventional construction. It may be assembled with other similar walls if desired.
No discussion has been had with respect to temperatures and wetting down of the cementitious materials subsequent to their deposition. In the preferred embodiments, the panels are manufactured in a controlled environment in a factory. In such an instance, it is obvious that the temperature, humidity, and other environmental factors may be controlled relatively closely. Where the assembly of the panel structure is not under such controlled conditions, it may be necessary to wet down the panel again within 24 hours of the time the initial cementitious mixtures are laid. Also it should be emphasized that the temperature should always be above freezing but below a temperature which would dry the ceent mixtures too quickly.
Having thus described the invention in some detail, it will be obvious to those having ordinary skill in the art that certain modifications could be made without departing from the spirit of the invention. Additionally, the language used to describe the invention is not intended to be limiting, rather it is intended that the only limitations to be placed on the invention are those set out in the appended claims. | A method of making a building panel and the panel made by the steps which include laying a mold form horizontally, laying bricks in the pattern indicated in the mold form and depositing a fibrous and cementitious mixture in the spaces between the bricks and over the tops of the bricks. Providing a reinforcing lattice work and forcing it into the still soft cementitious mixture. Subsequently, a resin insulating material is foamed in situ in the mold cavities formed between the elements of the lattice work. Optionally, a smooth finish coat of material may be troweled or sprayed over the insulation material. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a Continuation-in-Part of U.S. application Ser. No. 14/685,933, filed on Apr. 14, 2015, and entitled “AN HVAC MODULE HAVING AN OPEN ARCHITECTURE” the entire content of which is hereby incorporated by reference.
TECHNICAL FIELD OF INVENTION
The present application relates to a heating, ventilation, and air conditioning (HVAC) module for a passenger vehicle.
BACKGROUND OF THE INVENTION
Traditional motor vehicles typically have a single temperature-controlled zone air conditioning system designed to provide conditioned air to the front occupants in the passenger compartment of the vehicle. As the size of the vehicles increases, and as vehicle occupants demand more luxurious features, air conditioning systems capable of providing multiple temperature-controlled zones, or multi-zone air conditioning systems, have become more prevalent. A multi-zone air conditioning system allows the driver, front passenger, and even the rear seat passengers to have separate controls of the temperature in their respective zone, thereby improving the comfort of the occupants in each zone. A larger size vehicle, such as sport utility vehicles (SUV) and mini-vans, may have up to four or more individual zones in the passenger compartment. As an example, the passenger compartment of a mini-van may be divided into four separate zones, where the driver space may be zone 1, the front passenger space may be zone 2, the second row seating space may be zone 3, and the third row seating space may be zone 4.
Traditional heating, ventilation and air conditioning (HVAC) modules for single zone air conditioning systems are generally designed to optimally utilize the amount of available space in a given type of vehicle as well as to conform to the shape of that space. HVAC modules that have the capability of providing temperature control for multiple zones are specifically designed, tooled, and manufactured for the exact number of zones. The production volume for multiple zone HVAC modules is typically much lower than that for single or dual zone modules. As such, it is much more expensive to design such a multiple zone HVAC module for so few vehicles. Additionally, it would be disruptive to the manufacturing cell and the manufacturing process in general to be forced to build an entirely different HVAC module to achieve an additional temperature-controlled zone.
Traditional multiple zone HVAC modules use partition walls extending up to the individual heat exchangers within the HVAC module to provide multiple streams of conditioned airflow. These multiple streams of airflow are used to achieve multi-zone climate control in the associated passenger compartments. The greater the number of zones, the greater number of partition walls are required, and the larger the sizes of heat exchangers are required. However, multiple zone HVAC modules must conform to the limited size and shape where a single zone HVAC module would be in place, thereby requiring additional functions to be added without utilizing any extra space. Due to operating capacity and packaging constraints, two separate dual HVAC modules are commonly employed in larger vehicles to achieve multi-zone operation, where a two zone module is installed between the firewall and the vehicle dash and another, one or two zone, HVAC module in the area of the trunk.
However, implementation of traditional, partitioned, dual HVAC modules is challenging. For example, dual HVAC modules can require excessive packaging space in the host vehicle, additional air ducts, additional lines and fittings, additional refrigerant, additional coolant, additional mass, higher operating noise levels, higher cost and increased system complexity that often translates into elevated quality and warranty issues. Such systems require additional energy and larger supporting components such as compressors, water pump, condenser, alternator, line sets, and ducts. As a consequence, the dual module approach results in increased vehicle fuel consumption and increased exhaust emissions. All of these items significantly contribute to overall vehicle cost and operating costs.
SUMMARY OF THE INVENTION
The present disclosure provides an open architecture, multi-zone heating, ventilation, and air conditioning (HVAC) module for a passenger vehicle, having an anti-backflow control and a method for operating the anti-backflow control.
According to a first aspect of the present disclosure, an apparatus is provided for an HVAC module for a passenger vehicle comprising a housing defining an air inlet, a front zone air outlet, and a rear zone air outlet; an evaporator disposed within the housing downstream of the air inlet; a heater disposed within the housing downstream of the evaporator; a cold air chamber downstream of the evaporator defined in the housing between the evaporator and the heater, the cold air chamber having a first pressure; a hot air chamber downstream of the heater defined in the housing between the heater and a first interior surface of the housing, the hot air chamber having a second pressure quantitatively lower than the first pressure of the cold air chamber; a cold air stream path defined by a second interior surface of the housing and an interior partition in the housing, the cold air stream path extending from the cold air chamber to a rear zone mixing chamber defined by the housing, the rear zone mixing chamber having a third pressure and being in fluid communication with the rear zone air outlet; and a control valve disposed in the housing between the cold air chamber and the rear zone mixing camber, the control valve configured to controllably release cold air from the cold air chamber along the cold air stream path into the rear zone mixing chamber, wherein the control valve throttles cold air from the cold air chamber thereby regulating the third pressure of the rear zone mixing chamber such that the third pressure remains quantitatively lower than the second pressure of the hot air chamber. This prevents cold air in the cold air stream path from flowing back into the hot air chamber.
The rear zone mixing chamber may have a rear zone blend valve disposed within the rear zone mixing chamber. The rear zone blend valve may be configured to selectively direct air flow from the cold air stream and the hot air chamber to the rear air outlet.
The control valve disposed in the housing between the cold air chamber and the rear zone mixing chamber may be a butterfly valve.
The HVAC module may further comprising a front zone mixing chamber defined by the housing and positioned downstream of the evaporator adjacent to the cold air chamber and the hot air chamber. The front zone mixing chamber may be in fluid communication with the front zone air outlet.
A front zone blend valve may be disposed in the front zone mixing chamber to selectively direct air flow from the cold air chamber and the hot air chamber to the front zone air outlet.
This structure may be applied to an HVAC module having no more than one blower assembly that moves air through the housing from the inlet to the front zone air outlet and/or the rear zone air outlet.
According to another aspect of the present disclosure, a method of controlling a backflow of cold air into hot air chamber in an open architecture HVAC module is provided. The HVAC module having an air inlet, an evaporator downstream of the air inlet, a cold air chamber downstream of the evaporator, a heater downstream of the cold air chamber, a hot air chamber downstream of the heater, a rear zone mixing chamber downstream of the cold air chamber and the hot air chamber, a rear zone air outlet, a control valve disposed between the cold air chamber and the rear mixing chamber, and a blend valve disposed in the rear zone mixing chamber. The method comprising the steps of reading a pressure of the cold air chamber, a temperature of the cold air chamber via a thermistor measurement, a pressure of the hot air chamber, and a temperature of the hot air chamber; setting a discharge air flow rate target and a discharge temperature target for the rear zone air outlet; calculating a resistance of the anti-backflow control valve; calculating a resistance of the blend valve; determining a position of the anti-backflow control valve corresponding to the calculated resistance of the control valve, the determination based on pre-programmed control valve calibration data; determining a position of the blend valve corresponding to the calculated resistance of the blend valve, the determination based on pre-programmed blend valve calibration data; moving the control valve to the position of the control valve determined to correspond to the resistance of the control valve calculated; moving the blend valve to the position of the blend valve determined to correspond to the resistance of the blend valve calculated.
The pre-programmed control valve calibration data may be a control valve look-up table.
The pre-programmed blend valve calibration data may be a blend valve look-up table.
The method may be applied to an HVAC module having no more than one blower assembly configured to induce air to flow through the housing from the inlet to at least one of the front zone air outlets and/or the rear zone air outlets.
These and other features and advantages of this invention will become apparent upon reading the following specification, which, along with the drawings, describes preferred and alternative embodiments of the invention in detail.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention will be further described, by way of example, with reference to the accompanying drawings in which:
FIG. 1 , illustrates a cross-sectional view of an open architecture HVAC module having an anti-backflow control valve;
FIG. 2 , is a flowchart illustrating a method for preventing back flow of air in the HVAC module of FIG. 1 by controlling an anti-backflow control valve and a blend valve; and
FIG. 3 , is a schematic illustrating valves controlled by the method of FIG. 2 .
Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to illustrate and explain the present invention. The exemplification set forth herein illustrates an embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF INVENTION
Shown in FIG. 1 is one form of an HVAC module 200 having an anti-backflow control valve 290 of the present disclosure. Where practical, reference numbers for like components are commonly used among the figures. Referring to FIG. 1 , the present disclosure pertains to an open architecture HVAC module 200 . An open architecture HVAC module means, in part, that the cores of the heat exchangers 204 , 206 are not partitioned into dedicated zones by the internal partition walls 208 , 210 of the HVAC housing 202 , and all or a portion of the air flow through the core of each heat exchanger 204 , 206 may be intercepted by blend valves 224 a , 224 b , and directed to any one or more zones. In other words, the total core of each heat exchanger 204 , 206 , as opposed to only a portion of the core of the each heat exchanger 204 , 206 , can be utilized to condition the air flow to one or more of the zones at all times. Unlike the prior art HVAC modules, an open architecture HVAC module 200 enables super cooling or super heating of any one zone, or enables the delivery of different temperature air to multiple zones. Super cooling or super heating is accomplished by directing the total mass air flow (100% of air-flow) exiting the core of the evaporator 204 or heater unit 206 to any one of the multiple zones.
The improved HVAC module 200 includes an HVAC housing 202 containing an evaporator 204 and the heater unit 206 spaced from and downstream from the evaporator 204 . A cold air chamber 226 is defined in the HVAC housing 202 between the evaporator 204 and heater unit 206 , and a hot air chamber 228 is defined between the heater unit 206 and an interior surface of the HVAC housing 202 downstream of the heater unit 206 . Air flow through the evaporator 204 exits directly into the cold air chamber 226 and air flow through the heater unit 206 exits directly into the hot air chamber 228 . The HVAC housing 202 defines an air inlet 201 and four air outlets 230 , 232 , 234 , 236 ; one air outlet for each of the temperature controlled zones for supplying temperature controlled air to the respective zones. In FIG. 1 , the HVAC blower unit and its connection to the air inlet 201 are on the back side of the HVAC housing 202 , and therefore are not shown. FIG. 1 also does not show two of the air outlets 232 and 236 , but it will be understood that those air outlets 232 and 236 are directly reflected on the back side of the HVAC module 200 and are hidden behind the upper partition wall 208 and the lower partition wall 210 , respectively. Two of the air outlets 230 , 232 for directing conditioned air to a front zone of a vehicle, two of the air outlets 234 , 236 for directing conditioned air to a rear zone of the vehicle.
The upper vertical partition wall 208 , or first partition wall 208 , may extend partially into the cold and hot air chambers 226 , 228 from an interior surface of the HVAC housing 202 between the first outlet 230 and second outlet 232 . The upper portion of the HVAC housing 202 defines a front zone mixing chamber 212 in fluid communication with the front zone air outlets 230 , 232 . Similarly, the lower vertical partition wall 210 , or second partition wall 210 , may extend partially into the cold and hot air chambers 226 , 228 from an interior surface of the HVAC housing 202 between the third outlet 234 and fourth outlet 236 . The lower portion of the HVAC housing defines a rear zone mixing chamber 216 in fluid communication with the rear zone air outlets 234 , 236 . In FIG. 1 , the front zone outlets 230 , 232 are adjacent the upper portion of the HVAC housing 202 , and the rear zone outlets 234 , 236 are adjacent the lower portion of the HVAC housing 202 .
It should be noted that the improved HVAC module 200 does not include a horizontal partition wall. It should also be noted that the vertical partition walls 208 , 210 , if included extend only partially into the cold and hot air chambers 226 , 228 , and do not extend to or through the evaporator 204 and heater unit 206 . Each of the mixing chambers 212 , 216 is in fluid communication with both the cold air chamber 226 and hot air chamber 228 . Disposed in each of the mixing chambers 212 , 216 , is a blend valve 224 a , 224 b configured to selectively divert at least a portion of air flow from the cold air chamber 226 and hot air chamber 228 to its respective air outlet 230 , 232 , 234 , 236 . It will be understood that the half of the HVAC module 200 shown in FIG. 1 is directly reflected on the back side of the HVAC module 200 behind the upper vertical partition wall 208 and lower vertical partition wall 210 . Therefore there are mixing chambers and blend valves on both halves of the HVAC module 200 . Only a single blower (not shown) is required to induce air through the improved HVAC module 200 to the multiple zones.
A first mode valve 238 for delivering air to the windshield, a second mode valve 240 for delivering air to the dash, and a third mode valve 242 for delivering air to the feet of the driver are shown downstream of the front zone mixing chamber 212 . Downstream of the rear zone mixing chamber 216 may be mode valves (not shown) for delivering air flow to the torso or feet of the rear passengers.
The evaporator 204 is spaced from and disposed upstream of the heater unit 206 within the HVAC housing 202 . The cold air chamber 226 is defined by the volume of the HVAC housing 202 between the evaporator 204 and the heater unit 206 , and the hot air chamber 228 is defined by the volume of the HVAC housing 202 between the heater unit 206 and a portion of the interior surface of the HVAC housing 202 downstream of the heater unit 206 .
A cold air stream path 286 is defined by a portion of the housing 202 and an interior partition in the housing. The cold air stream path 286 extends from the cold air chamber 226 to the rear zone mixing chamber 216 . The cold air stream path 286 is the path that cold air takes to move from the cold air chamber 226 to the rear zone mixing chamber 216 .
As mentioned, a single blower assembly is provided to draw air into the HVAC module 200 to be conditioned and conveyed to the individual zones. The mass flow rate and velocity of air flow to each zone may be controlled by the combination of the speed of the blower and airflow control valves provided in the vent outlet to each of the zones. The blower assembly may draw in a stream of air external to the vehicle or a stream of recycle air from within the vehicle.
The temperature blend valves 224 a , 224 b of each mixing chamber may selectively intercept one of the hot and cold air streams, or a combination of both, from the cold and hot air chambers 226 , 228 , respectively, to provide the desired temperature to the zones. The zonal specific airflow rate after mixing is controlled by a coordination of the blower, of the respective current mode valve position, and the balancing of other zonal mode valves 238 , 240 , 242 . A benefit of this open architecture is that the total capacity of the evaporator 204 and heater unit 206 may be utilized to condition the air for any one of the zones, as well as providing variable air flow to the zones. Another benefit is that by selectively opening and closing the airflow control valves, the total air flow through the heat exchangers 204 , 206 may be directed to any one of the zones. The mode valves 238 , 240 , 242 may be coordinated to direct up to 100 percent of the zone one air flow to one of the defrost vents, passenger vents, or floor outlets.
The cold air chamber 226 has a pressure P ev and a temperature T c . The hot air chamber 228 has a pressure P htr and a temperature T h . The rear zone mixing chamber has a pressure P mix . For the purpose of the present disclosure, the rear zone air outlet 234 has a target discharge air flow rate Q tot and target discharge temperature T mix . As a general rule, the pressure P ev of the cold air chamber 226 is always quantitatively greater than the pressure P htr of the hot air chamber 228 due to the added resistance of passing through the heater 206 .
It has been discovered that in certain limited circumstances, cold air from the cold air stream path 286 reaches the rear zone mixing chamber 216 and flows back into hot air chamber 228 . This occurs when the rear zone blend valve 224 b is in a position to provide nearly all cold air to the rear zone air outlet 234 and the front zone blend valve 224 a is in a position to provide nearly all hot air to the front zone air outlets, with the front zones demanding high airflow rates. This position of the rear zone blend valve 224 b places little resistance on the cold air stream, thereby increasing the pressure P mix in the rear zone mixing chamber 216 , while such a position of the front zone blend valve 224 a and the required high flow rates causes the pressure P htr to decrease. When P mix increases to become closer to P ev and P htr decreases, P mix becomes quantitatively greater than P htr . In this situation, cold air from the cold air stream path 286 reaches the rear zone mixing chamber 216 and then flows back toward to the hot air chamber 228 . This cold air mixes with the hot air in the hot air chamber 228 , thereby cooling the air in the hot air chamber 228 and reducing the temperature of the air flowing to the front zone air outlets.
It is thus desirable to reduce or prevent the backflow from the cold air stream path 286 to the hot air chamber 228 . Utilizing an anti-backflow control valve 290 between the cold air chamber 226 and the rear zone mixing chamber 216 to control the release of cold air from the cold air chamber 226 regulates the pressures of the HVAC module by creating a pressure drop in the cold air stream path 286 . Thus, the anti-backflow valve 290 helps to maintain the pressure P mix of the rear zone mixing chamber such that it is quantitatively less than the pressure P htr of the hot air chamber 228 . The anti-backflow valve 290 increases the resistance on the cold air along the cold air stream path 286 by throttling air from the cold air chamber 226 , thereby decreasing the pressure of the cold air as it moves to the rear zone mixing chamber 216 . The anti-backflow control valve 290 may act independently of the fluid communication of the hot air chamber to the rear zone mixing chamber such that the control valve 290 does not affect the cross section of the fluid communication between the hot air chamber 228 and the rear zone mixing chamber 216 . Where the mixing valve is controllable by the HVAC system itself, it may be feasible to replace the rear zone blend valve 224 b with two separately operable valves, of which one is dedicated to the cold air stream path 286 and the other one to the hot air exiting the hot air chamber 228 . The separate anti-backflow control valve 290 in addition to the rear zone blend valve 224 b as shown in FIG. 1 , however, is suited for all arrangements, including those, in which the rear zone blend valve 224 b is externally controlled and inaccessible to the HVAC control.
FIG. 2 illustrates a method for operating 300 an anti-backflow control valve 290 of an open architecture HVAC module as shown in FIG. 1 . The method begins by reading a pressure of the cold air chamber P ev , a temperature of the cold air chamber T c , a pressure of the hot air chamber P htr , a temperature of the hot air chamber T h , and a pressure of the rear zone mixing chamber P mix at step 310 . Next, a discharge air flow rate target Q tot and a discharge temperature target T mix are set for the rear zone air outlet at step 320 . The method continues by calculating a resistance R c of the anti-backflow control valve at step 330 and calculating a resistance R h of the rear zone blend valve at step 340 . The resistance R c of the anti-backflow control valve may be calculated by Equation 1, while the resistance R h of the rear zone blend valve may be calculated by Equation 2. The method may be incorporated into an open architecture, multi-zone HVAC system such as the system and method of control described in U.S. patent application Ser. No. 14/801,862 which is hereby incorporated by reference in its entirety.
R
c
=
(
T
c
-
T
h
T
mix
-
T
h
)
2
P
ev
-
P
mix
Q
tot
2
Equation
1
R
h
=
(
T
c
-
T
h
T
c
-
T
mix
)
2
P
htr
-
P
mix
Q
tot
2
Equation
2
Alternatively, starting with an initial control valve position and a blend valve position, the resistance of the control valve R c and the resistance of the rear zone blend valve R h can be looked up from the pre-calibrated tables. The discharge air flow rate Q tot and a discharge temperature T mix may be calculated according to Equation 3 and Equation 4, respectively, and may be compared with the target temperature and flow rate to re-position the valves via a method proportional-integral-derivative (PID) control.
Q
tot
=
(
P
htr
-
P
mix
R
h
)
1
2
+
(
P
ev
-
P
mix
R
c
)
1
2
Equation
3
T
mix
=
(
P
ev
-
P
c
R
c
)
1
2
T
c
Q
tot
+
(
P
htr
-
P
c
R
h
)
1
2
T
h
Q
tot
Equation
4
The method continues at step 350 by determining a position of the control valve POS c corresponding to the calculated resistance of the control valve R c . The determination is based on referencing pre-programmed control valve calibration data. The pre-programmed control valve calibration data may be in the form of a look-up table, as shown in Table 1.
TABLE 1
Control
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Pos c
Valve
(0)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Position
Control
R c
R c
R c
R c
R c
R c
R c
R c
R c
R c
R c
Valve
(0)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Resistance
The method continues at step 360 by determining a position of the rear zone blend valve POS h corresponding to the calculated resistance of the rear zone blend valve R h . The determination is based on referencing pre-programmed control valve calibration data. The pre-programmed rear zone blend valve calibration data may be in the form of a look-up table, as shown in Table 2.
TABLE 2
Rear Zone
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Pos h
Blend Valve
(0)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Position
Rear Zone
R h
R h
R h
R h
R h
R h
R h
R h
R h
R h
R h
Blend Valve
(0)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Resistance
At step 370 , the method includes moving the control valve to the position of the control valve POS c determined to correspond to the resistance of the control valve R c calculated. Step 380 includes moving the rear zone blend valve to the position of the rear zone blend valve POS h determined to correspond to the resistance of the blend valve R h calculated.
FIG. 3 is a schematic illustrating valves controlled by the method of FIG. 2 . Based on the pressure of the cold air chamber P ev and the temperature of the cold air chamber T c , the anti-backflow control valve 290 is positioned to result in a cold air flow Q c . The rear zone blend valve is 224 b is positioned based on the pressure of the hot air chamber P htr and the temperature of the hot air chamber T h , and results in a hot air flow Q h . The cold air flow Q c and the hot air flow Q h mix in the rear mixing chamber 216 to result in a rear zone mixing chamber pressure P mix and a discharge air flow Q tot and discharge temperature T mix .
It is to be understood that the invention has been described with reference to specific embodiments and variations to provide the features and advantages previously described and that the embodiments are susceptible of modification as will be apparent to those skilled in the art. | HVAC module has an air inlet, an evaporator downstream of the blower and a heater downstream of the evaporator, and a rear mixing zone downstream of the evaporator and the heater, wherein a control valve prevents cold air from flowing back towards the hot air by regulating the pressure of the cold air. A method is devised to control anti-backflow control valve of such an HVAC module by the steps of reading pressure and temperatures at various points in the HVAC module; setting air flow and temperature discharge targets; calculating the resistance of the control valve and a bland valve; determining corresponding control valve and blend valve positions; and moving the control valve and blend valve to those corresponding positions. | 5 |
FIELD OF THE INVENTION
The present invention relates to gaskets, and more particularly, to a molded plastic gasket.
BACKGROUND OF THE INVENTION
Gaskets have been used for many years for providing a sealed connection between two relatively static members. Gaskets typically require a compressive load between the members being sealed in order for the gasket to provide an effective seal. For example, a gasket placed between two stationary members, such as an engine block and an oil pan or an engine cylinder head and a valve/cam cover, is compressed between these elements.
One gasket design includes a molded plastic body having a solid molded sealing bead surrounding a central service aperture. The use of a solid molded sealing bead requires a large clamping force to ensure a good seal. The high clamping force results in a high compression force which in turn may cause the plastic to deform over time and thus reduce the effectiveness of the seal.
Accordingly, a need exists for a gasket having a sealing bead with a reduced propensity to deformation.
SUMMARY OF THE INVENTION
The present invention provides a gasket including a body defining at least one service aperture. A sealing bead is formed integral to the body and surrounds the service aperture. The sealing bead includes a first outwardly extending segment and a first concave channel opposite the first outwardly extending segment. The first concave channel is defined by a second outwardly extending segment and a third outwardly extending segment.
The present invention further provides an alternative embodiment in which a gasket has a body defining at least one service aperture and including an integrally formed sealing bead. The sealing bead includes an annular sealing member molded to the body, and the annular sealing member is opposite an outwardly projecting sealing bead segment.
In a second alternative embodiment, the present invention provides a gasket having a body defining at least one service aperture and a sealing bead integrally formed with the body. The sealing bead includes an internal chamber filled with a pressurized gas.
A third alternative embodiment of the gasket includes a body composed of a first polymeric material and defining at least one service aperture. The body has an integrally formed sealing bead. The sealing bead defines a chamber filled with a second polymeric material.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a perspective view of a molded plastic gasket according to the principles of the present invention;
FIG. 2 is a cross sectional view taken along line 2 — 2 of FIG. 1 ;
FIG. 3 is a perspective view of a molded plastic gasket according to an alternative embodiment of the present invention;
FIG. 4 is a cross sectional view taken along line 4 — 4 of FIG. 3 ;
FIG. 5 is a perspective view of a molded plastic gasket according to a second alternative embodiment of the present invention;
FIG. 6 is a cross sectional view taken along line 6 — 6 of FIG. 5 ;
FIG. 7 is a perspective view of a molded plastic gasket according to a third alternative embodiment of the present invention; and
FIG. 8 is a cross sectional view taken along line 8 — 8 of FIG. 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring now to FIG. 1 , a gasket 10 according to the principles of the present invention is shown. It will be understood that the shape of the gasket 10 is for illustrative purposes only and does not limit the scope of the present application. The gasket 10 will now be described as depicted in FIGS. 1–8 , wherein common reference numbers are utilized to represent the same or similar elements. In overview, the gasket 10 has a body 12 including a service aperture 14 and a sealing bead portion 16 .
With reference generally to FIGS. 1–8 , the service aperture 14 is typically formed in the center of the body 12 , along a centerline C. Preferably the body 12 is generally molded from a heat resistant polymer, such as, for example, glass fiber filled polyamide 12 (or other nylons) or glass fiber filled polyphenylene sulfides (PPS), which exhibit good flexibility, resistance to automotive fluids, and resistance to engine temperatures. The body 12 further has a first end 18 , a second end 20 and a thickness T. The first end 18 and second end 20 may each further include a mounting aperture 22 for receipt of a fastening mechanism (not shown), such as, for example, a bolt or screw, therethrough. The body 12 also has a first surface 24 and a second surface 26 . Although the body 12 is shown as being ring-shaped and the service aperture is illustrated as circular, it should be understood that other shapes can be utilized depending upon the size and shape of the surfaces to be sealed. Furthermore, the number of mounting apertures may also be varied depending upon the size and shape of the surfaces to be sealed.
In one embodiment, with specific reference to FIGS. 1 and 2 , the sealing bead portion 16 surrounds the service aperture 14 and is integrally formed with the body 12 . With reference to FIG. 2 , the sealing bead portion 16 includes a first outwardly extending bead 28 which projects beyond the first surface 24 of the body 12 . The first outwardly extending segment 28 has a height H 1 which may be approximately equivalent to the thickness T of the body 12 . The first outwardly extending bead 28 is opposite a first concave channel 30 formed in the second surface 26 of the body 12 . The first concave channel 30 is defined in part by a second outwardly extending bead 32 and a third outwardly extending bead 34 . Channel 30 may include a depth that is greater than a height of either or both of the second and third outwardly extending beads 32 , 34 . Both the second and the third outwardly extending beads 32 , 34 are formed on the second surface 26 of the body 12 . The second outwardly extending bead 32 has a height H 2 and the third outwardly extending bead 34 has a height H 3 . Typically, the height H 2 and height H 3 are substantially the same, but it should be noted that the heights H 2 and H 3 can be varied according to the particular application. In this embodiment, the heights H 2 and H 3 are generally equivalent in size to the thickness T of the body 12 .
The second and third outwardly extending beads 32 , 34 are also generally opposite a second concave channel 36 and a third concave channel 38 , respectively. The second and third concave channels 36 , 38 are formed in the first surface 24 of the body 12 on opposite sides of the first outwardly extending bead 28 . The sealing bead portion 16 of this embodiment ensures a tight seal through the first, second and third channels 30 , 36 , 38 which enable the sealing bead portion 16 to slightly deform under pressure without altering the effectiveness of the seal. Any of the outwardly extending beads 28 , 32 or 34 can be of generally triangular, rounded, rectangular, or any of a wide variety of other cross-sectional shapes that will occur to those skilled in the art. Any or all of such beads can be of the same height relative to the body 12 , or one or more of these beads can have a height relative to the body 12 that is different from that of any one or more of the other beads.
An alternative embodiment of the gasket 10 ′ is shown in FIGS. 3 and 4 . In this embodiment, the sealing bead portion 16 ′ includes an annular channel 100 for receipt of a compressible ring 102 therein. The compressible ring 102 may be integrally formed with the sealing bead portion 16 ′ or affixed to the annular channel 100 in a post processing step. The compressible ring 102 may be formed of any elastomeric material, such as natural or nitrile rubber, for example, which exhibit a low degree of compressive stress relaxation.
Opposite the compressible ring 102 is an outwardly extending bead 104 . The outwardly extending bead 104 includes a first angled sidewall 106 and a second angled sidewall 108 extending from a generally planar top portion 110 . The outwardly extending bead 104 extends from the second surface 26 of the body 12 . The sealing bead portion 16 ′ is generally symmetric about a Y-axis Y 100 of the sealing bead portion 16 ′. Although the outwardly extending bead 104 is shown in a polygonal shape, it shall be noted that the shape of the outwardly extending bead 104 can be varied according to the particular sealing application. The configuration of this sealing bead portion 16 ′ provides resistance against deflection through the use of the compressible ring 102 . Specifically, the compressible ring 102 provides a stress resilient surface for clamping against, thus ensuring the effectiveness of the seal over time.
With particular reference now to FIGS. 5 and 6 , a second alternative embodiment of the gasket 10 ″ is shown. In this embodiment, the sealing bead portion 16 ″ includes a first outwardly extending bead 200 and a second outwardly extending bead 202 integrally formed with the body 12 . The sealing bead portion 16 ″ is generally symmetrical about a Y-axis Y 200 of the sealing bead portion 16 ″. The first and second outwardly extending beads 200 , 202 each include a first angled sidewall 204 and a second angled sidewall 206 extending from a generally planar top portion 208 . The first outwardly extending bead 200 extends from the first surface 24 of the body 12 while the second outwardly extending bead 202 extends from the second surface 26 of the body 12 . The first outwardly extending bead 200 has a height H 200 and the second outwardly extending bead 202 has a height H 202 . The heights H 200 and H 202 are approximately the same as the thickness T of the body 12 , but can also be greater than or less than the thickness T, depending upon a particular application. Although the first and second outwardly extending beads 200 , 202 are shown in a polygonal shape, it shall be noted that the shape of the first and second outwardly extending beads 200 , 202 can be varied according to the particular sealing application.
The first outwardly extending bead 200 and second outwardly extending bead 202 are generally positioned opposite each other and define an annular channel 210 in a center 212 of the body 12 . The annular channel 210 is configured for receipt of a pressurized gas 214 . The pressurized gas 214 retained in the annular channel 210 may comprise nitrogen, argon, or other inert gases. The pressurized gas 214 located in the sealing bead
A third alternative of the gasket 10 ′″ present invention is illustrated in FIGS. 7 and 8 . The sealing bead portion 16 ′″ of this embodiment is integrally formed with the body 12 and includes a first outwardly extending bead 300 and a second outwardly extending bead 302 . The first and second outwardly extending beads 300 , 302 are generally symmetric with respect to a Y-axis Y 300 of the sealing bead portion 16 ′″. The first outwardly extending bead 300 extends from the first surface 24 of the body 12 and the second outwardly extending bead 302 extends from the second surface 26 of the body 12 . The first and second outwardly extending beads 300 , 302 each include a top segment 304 extending between a first angled sidewall 306 and a second angled sidewall 308 . The first outwardly extending bead 300 has a height H 300 and the second outwardly extending bead 302 has a height H 302 . The heights H 300 and H 302 are generally larger than the thickness T of the body 12 , although shorter heights may also be utilized according to a specific application. Although the first and second outwardly extending beads 300 , 302 are shown in a polygonal shape, it shall be noted that the shape, as well as the size, of the first and second outwardly extending beads 300 , 302 can be varied according to the particular sealing application.
The first and second outwardly extending beads 300 , 302 define an inner chamber 308 for receipt of a core material 310 therein. The core material 310 may be comprised of a microcellular foam, including, for example, glass fiber filled polyamide 12 (or other nylons) or glass fiber filled polyphenylene sulfides (PPS), with microcellular pockets of nitrogen gas providing flexibility and elasticity or any other similar suitable material. The core material 310 is shown in the inner chamber 308 , however, it shall be noted that the core material 310 could be located substantially throughout the body 12 . The core material 310 provides a resilient clamping point, enabling the seal to maintain its integrity over time.
The gaskets 10 , 10 ′, 10 ″, 10 ′″ of the present invention generally ensure a tight seal over time by providing a resilient clamping point. In particular, the three concave channels 30 , 36 , 38 , enable slight deformation without a decrease in seal strength while the compressible ring 102 , the pressurized gas 214 and the core material 310 in FIGS. 5 through 8 create a sealing bead which are resilient.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. | A gasket is provided having a body including at least one service aperture and an integrally formed sealing bead portion. In an embodiment, the sealing bead portion includes a first outwardly extending bead and a first concave channel opposite the first outwardly extending bead. The first concave channel is defined by a second outwardly extending bead and a third outwardly extending bead. In an alternative embodiment, the sealing bead portion includes an annular sealing member molded to the body, and the annular sealing member is opposite an outwardly projecting sealing bead. In a second alternative embodiment, the sealing bead portion includes an internal chamber filled with a pressurized gas. In a third alternative embodiment, the sealing bead portion defines a chamber filled a polymeric material. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to the processing of a wet sludge with a drying medium obtained from the wet sludge after having the moisture substantially reduced to constitute the drying medium, and to apparatus for carrying out the process.
2. Description of the Prior Art
In the field of the disposal of wet sludge material which may include paper sludge as a result of the deinking process, human sewage or similar make-up of sludge which has a wetness of an order that causes it to clump-up and plug apparatus intended to facilitate its disposal, a sludge disposal system is seen in Williams U.S. Pat. No. 5,018,456 of May 28, 1991. In that patent the sludge forms a primary source of fuel for use in a furnace which produces hot gas for drying the sludge material, however, the apparatus depends on recycling some sludge, after being reduced, for use as a drying medium for the incoming sludge.
There is a great need for a way of disposing of wet sludge, but the difficulty is that sludge in its wet condition clumps up and moves as a spongy mass that resists normal efforts to break up and divide the sludge so the reduction in the moisture binder will allow the solids to separate sufficiently to encourage drying. The usual operation of prior art apparatus is to dry the sludge by recirculating the dried output which reduces the total output of the apparatus by the amount recycled, and no increased horsepower is required.
BRIEF SUMMARY OF THE INVENTION
It has been found that under certain conditions, in the operation of apparatus for grinding the sludge, portions of the ground output can act as a fuel to produce heat at a sufficient temperature level to become effective as a source of drying heat.
It is, therefore, an object of the invention to subject the flow of disposable ground sludge material to a supply of heat where only the heated coarse granular fractions are diverted from the fine fractions and circulated into the incoming wet sludge as a drying agent to perform an important function which changes the tendency of the wet sludge to clump and causes it to form a loose nearly homogenized flow in preparation for a grinding step without plugging the grinding apparatus and without reducing the output capacity.
An object of the invention is to process a mix of wet sludge and coarse fractions produced during the grinding of the mix in a hot atmosphere wherein a grinding mill forceably throws its output into a classifier so the material impacts against a target surface which intercepts the heated coarse fractions, while allowing the fine fractions to escape, and directs the heated coarse fractions into incoming wet sludge for initiating a moisture reducing function on the incoming wet sludge.
Another object of the invention is to establish a grinding mill outflow of heated ground material normally consisting of coarse and fine fractions and to provide a way of scalping off the coarse fractions so that substantially fine fractions are discharged as a product to be employed as fuel in a furnace which then can generate a source of heat for moisture reduction, or for other purposes, while the hot coarse fractions are circulated into the incoming wet sludge to overcome the clumping tendency and promote drying.
A further object of the invention is to process a wet sludge of the character indicated in apparatus that initially breaks up the formation of clumps or clusters of sludge so it is rendered relatively easy to grind and thereby produce a mixture of coarse and fine fractions, and to recirculate only the coarse fractions into the incoming wet sludge to reduce clumping of the wet sludge while collecting only the fine fractions for use in a furnace which produces heat to initiate drying of the wet sludge during the grinding thereof.
The invention includes a method for disposing of wet sludge by utilizing coarse fractions to mix into the sludge so as to reduce the quantity of material that usually falls back to the mill in direct counterflow against the product output from the mill; thereby effecting a reduction of horsepower needed for grinding, and using the separated fine fractions as fuel to develop drying heat.
The foregoing and other objects will be set forth in greater detail as the description proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings represent the preferred mode of the invention, and wherein:
FIG. 1 is a schematic diagram of components of apparatus which renders the invention practical;
FIG. 2 is a fragmentary sectional view taken along line 2--2 in FIG. 1 of the apparatus for scalping coarse fractions from the output of a grinding mill seen in FIG. 1;
FIG. 3 is a schematic view of a furnace for utilizing the fine fractions as a fuel for drying purposes; and
FIG. 4 is a modified classifier portion of the apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Looking at the schematic view of FIG. 1, the embodiment includes a material grinding mill 10 which may be a hammer mill driven by a suitable motor 10A belt connected to the rotor shaft 11 to drive that rotor in a counter clockwise direction so material entering the mill housing 22 from a feed delivery conduit 31 at one side of a partition 14 is ground and then projected or thrown upwardly-through the outlet passage 12 then into a stack made up of sections 14A and 14B. The stack extension 14B terminates in a separator casing 15 which is connected to an exhaust conduit or stack 16 leading to a cyclone separator 17 associated with a blower 18 which draws off the fine fractions along with gases and air from the casing 15. The cyclone separator 17 discharges the fine fractions through a rotary gate for discharge into a bin or other collector 20 for disposal as a fuel. A suitable source of hot drying gases is delivered by pipe 21 to the mill housing 22 to supply the heat into the incoming wet sludge for reducing the moisture in the same.
As seen in FIG. 1, wet sludge material is brought to the apparatus by a suitable belt or other conveyor 23 and dropped into the housing 24 and from there it falls into a flail agitator rotor 25 driven by motor means 26. The agitator can be a J. C. Steele, Stateville, N.C., Model No. 2030E Mixer, or the equivalent. The wet sludge is severely agitated to improve mixing and minimize clumping. The separator casing 15 is provided with a coarse material collecting chute 27 which directs the material into discharge conduit 27A connected through an airlock device 28 conduit 29 opening to the housing 24. In this manner, the heated coarse fractions, to be described presently, can be delivered to the housing 24 where it is severely agitated and intermingled with the wet sludge to initiate moisture reduction of the wet sludge. In the process of being severely mixed, the combined sludge and coarse fractions are deposited in a motor operated spiral screw feeder 37, such as a Stateville, N.C., Model EVEN FEEDER, No. 88C, or an equivalent. The feeder 37 has a cross-feed screw shaft 30 which is motor driven (not shown) to collect the material and concentrate it into a discharge conduit 31 opening into the mill housing 22 to fall adjacent the inflow of hot gases and air from conduit 21.
Referring now to FIGS. 1 and 2, it is seen that the casing 15 carries a target plug 33 in the axis of the casing 15 to present an impact surface 34 against which material thrown up from the mill 10 impinges. That impinging material is caused to collect on a circumferential shelf 35 positioned in the casing 15 at an elevation below the level of the impact surface 34. The rising column of gas and air which carries a mix of coarse and fine fractions is forced to travel laterally to get around the plug 33, and in so doing the coarse fractions are thrown out and into the chute 27 while some of the coarse fractions accumulate on the circumferential shelf 35. In this arrangement the fine fractions are not seriously impeded but move around the plug 33 and into the conduit 16 by the suction effect of the blower 18 associated with the cyclone separator 17.
The casing 15 (see FIG. 2) has its shelf 35 interrupted by a chute 27 which opens into a conduit 27A which directs the coarse fractions toward the rotary air lock 28. It is necessary to rotate an air lock to allow the coarse material to pass by a gravity fall into the conduit 29, otherwise the blower 18 would pull a negative pressure in conduit 29 to prevent an effective passage of the heated coarse fractions into the wet sludge in housing 24.
The schematic diagram in FIG. 3 illustrates means for collecting the fine fractions from the outlet conduit 16 by the action of the blower 18 which draws the fines into the cyclone separator 17 where the fines pass out into a bin 20. Alternately the fines may be released through a bin 20A through a rotary gate 38 to be conveyed in an air stream conduit 39, under the power of a blower 39A, to the burner head 40 for a furnace. The fines function as a fuel to aid the supply of a suitable fuel from a supply source 41. Under certain conditions the quantity of fine fractions can make up the largest source of fuel. In start up of the apparatus, a suitable fuel is used to raise the system to operating temperature levels. A suitable furnace 42 produces a supply of hot gaseous medium at conduit 21 which, as seen in FIG. 1, connects into the housing 22 to supply heat at a temperature of the order of 1500° F. The ash from the furnace 42 is discharged into a collector type grate 43 which is operated by motor 44, and the accumulation is carried off by a suitable conveyor 45.
An alternate form of apparatus is seen in FIG. 4 wherein the classifier or separator casing 15A that is modified from that seen in FIG. 1. The modification embodies a spinner separator 46 in the form of a rotor disc 47 driven by a motor 48 through a suitable gear box 49 and drive shaft 50. The spinner separator 46 has two or more blades 51 which move in a circular orbit at about the elevation of a discharge conduit 52. The action of the blades 51 is to drive the oversize fractions into the conduit 52 while allowing the lighter fine fractions to impact on the center disc 47 and pass around and through the orbit of the blades 51 and exit at outlet conduit 16A, as before. The conduit 52 connects into a rotary gate 53, and that gate releases the coarse and overweight fractions to pass through conduit 54 and mingle with the wet sludge arriving by belt conveyor 55 at the inlet means 56 for the housing 24. The view of FIG. 4 is only fragmentary, as what is not shown is like the apparatus seen in FIG. 1.
The view of FIG. 4 is seen to include a control center 57 having a fan speed control 58 for the spinner separator motor 48 through control lead 59. There is also a motor 60 connected to the blower 18 and a control lead 61 from the motor 60 to a speed control 62. The control center 57 is useful to select the dynamics in the apparatus as between the draw in the casing 15A and the feed rate to conduit 52 under the speed of the motor 48. There is a need to match the feed of the hot coarse fractions into the casing 24 with the evacuation of the fine fractions by blower 18 and delivered to the furnace 42.
In the operation of the foregoing apparatus, the hot gases and air at a temperature of about 1500° F. from a furnace (not shown) are supplied through conduit 21. The apparatus is brought up slowly to a temperature of the order of about 540° F. as measured at the outlet conduit 16. The wet sludge brought by the conveyor 23 is usually at about 62% water for paper sludge and 80% for sewage sludge, and as it is mixed by the flailing means 25, the drying effect initiated by the coarse fractions is to reduce the moisture condition of the mixture of sludge and coarse fractions to about 40% to 50% water content. To obtain this degree of drying effort it is intended that the rate of feed of wet sludge needs to be coordinated with the feed of the coarse fractions in conduit 29 by the rate of rotation of the air lock rotor 28 to get the moisture reduction down to about 40% to 50% water content level in the feeder 13. An example of this control may be exemplified by feeding wet sludge at the rate of ten tons per hour, and feeding back the coarse recycled fractions at conduit 29 at a rate of about five tons per hour.
The mixing of the wet sludge and coarse fractions takes place in the mixer 25 and then drops down into the multi-screw feed device 13. That device 13 is equipped with a plurality of screw devices 37 driven by motor 38 which advances the mixed sludge and coarse fractions toward the cross collector screw 30 driven by motor (not shown) to collect the advancing mix and direct it into the discharge conduit 31.
The system described above is placed in operation by supplying heat from a gas burner source through the hot gas pipe 21 at about 1500° F. at a very slow rate to bring the apparatus, and particularly the exhaust stack 16, up to a substantially uniform temperature of about 500° F. Thereafter, the wet sludge is slowly introduced during a predetermined residence time to the sludge housing 24 and feed device 13 and allowed to pass through the turbulance of the mixer 25 and down into the bottom feed device 13 where it is discharged at conduit 31 into the grinding mill 10 through the hot gas from conduit 21 which is at a temperature of about 1500° F. The mill 10 throws the material in a flow of the heated ground sludge upwardly through the mill stack 14A, stack extension 14B and into the separator casing 15 where separation of the heated coarse product from the fine product takes place due to the suction effect of the blower 18 associated with the cyclone separator 17. As the system continues, the course fractions are mixed with the wet sludge in the housing 24 by the operation of the flail rotor 25 so that the mixed material moves into the bottom feed device 13 establishing the operating system at the defined rate for disposing of the wet sludge in the manner set forth, and selectively using the fine fractions separated at the cyclone separator 17 as a useful product or as a fuel to augment the production of the hot gas supplied to the grinding mill 10 through conduit 21.
The foregoing apparatus performs the steps of a unique method for disposing of wet sludge resulting from the discarding of deinking sludge from paper plants, and human waste sewage sludge, both of which are rapidly becoming an environmental hazard. The unique method in a broad form is adapted to employ drying material in a transformation form as the medium to dry the wet sludge and render the wet sludge flowable as a composite material, subjecting the composite material to a step of converting that composite material into coarse and fine fractions in the presence of drying heat, thereby making it possible to remove the coarse fractions from the air stream to thereby employ the coarse fractions as the drying material to be mixed with the wet sludge, while collecting the fine fractions as a product of the method. The method can be continued at whatever rate is determined that will successfully dispose of the wet sludge.
The apparatus disclosed in the drawings is easily capable of rendering the method applicable to a high rate of disposing of the wet sludge.
The steps of the foregoing method, practiced by the apparatus comprises supplying heat to a grinding mill at the same time as a movement of the wet sludge through a mixer uses recirculated heated coarse fractions of the sludge that are not entirely reduced by grinding as a drying medium to reduce the wetness of the incoming sludge for improving the grindability of the mix of sludge and coarse fractions while reducing the horsepower and not impeding the mill output. The practice of this unique method is greatly facilitated by an arrangement of apparatus capable of processing the wet sludge and the resulting mixing of the sludge and heated coarse fractions of the ground sludge output from a mill so that a substantial disposal of large quantities of the objectionable sludge can be effected.
It is appreciated from the foregoing disclosure that modifications may come to mind that are essentially the equivalent in scope and result herein disclosed. | Apparatus for disposing of wet sludge by conversion to a substantially dry product during grinding of the wet sludge in a drying atmosphere which promotes the separation of the grindings into coarse fractions and fine fractions so that the coarse fractions in the dried condition can be directed to enter the supply of the wet sludge for reducing the moisture content to prepare the mix of wet sludge and coarse fractions for grinding in a drying heat atmosphere to perpetuate the supply of coarse fractions for moisture reduction of the wet sludge and a supply of the fine fractions as a product of the apparatus. | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates to decorative sheet materials generally, and more particularly to the manufacture of decorative sheet materials suitable for use as a flexible weatherable paint film.
BACKGROUND OF THE INVENTION
[0002] Manufacturers have shown increasing interest in using paint films in lieu of spray painting for providing a decorative surface finish for parts, such as automobile body parts. This manufacturing technique reduces the environmental concerns associated with painting and has the potential to reduce manufacturing costs. An automobile body part utilizing a plastic paint film to produce a high quality base coat/clear coat automotive finish is disclosed, for example, in U.S. Pat. No. 4,810,540, which is incorporated by reference herein. In producing the part, the paint film is typically formed into a contoured three-dimensional configuration corresponding to the shape of the outer surface of the part by suitable methods, such as by thermoforming.
[0003] Automotive manufacturers, for example, require that automotive parts have an exterior paint appearance which meets demanding performance and appearance specifications, such as weatherablility, resistance to ultraviolet light degradation, high gloss, and high distinctness-of-image (DOI). To meet these demanding requirements, paint film materials have been developed that have a number of layers of differing compositions and differing functions. For example, the paint films include a pigmented color coat layer, and where the paint film is intended to simulate the appearance of a base coat/clear coat paint finish, the film will also have an outer clear coat layer. In addition, the film may include a primer layer adhered to the color coat layer and an underlying adhesive layer as well as a thermoformable backing. The film may also have a removable protective mask layer which overlies and protects the paint film, and which can be removed after the automotive part has been manufactured.
[0004] Producing complex multilayer films of this type by conventional coating techniques requires multiple coating operations, typically performed by successive passes through a coating apparatus. The handling associated with each coating pass adds to the cost of the product and increases the opportunity for introducing flaws or defects which would result in inferior quality film materials.
SUMMARY OF THE INVENTION
[0005] The present invention addresses the problems and limitations associated with conventional coating technology and provides a process and apparatus for producing complex multilayer films with enhanced efficiency and assurance of quality. The method and apparatus of the present invention also provides the flexibility for producing various product designs or configurations.
[0006] In accordance with the present invention, multiple coating operations are performed in a single pass through the coating apparatus. The coatings are applied “wet-on-wet” as the film product is advanced through the coating apparatus. By this approach, complex multi-layer film products can be produced in a minimum number of successive passes through the coating apparatus. Multilayer films can be produced efficiently, economically and with a high assurance of quality. By reducing the number of passes required through a high temperature drying oven, product degradation is reduced. Additionally, the kinds of coatings which can be applied is expanded, making it possible, for example to apply temperature sensitive coatings or coatings of a viscosity or thickness which cannot readily be coated separately. The complex multi-layer film products can provide functional advantages that a single layer coating cannot provide.
[0007] In accordance with one broad aspect, the present invention provides a method of making a decorative sheet material comprising: directing a flexible carrier film through a coating station; depositing onto the surface of the carrier film a first coating layer of a solvent based clear coat composition; depositing onto the first coating layer a second coating layer of a solvent based pigmented color coat composition; directing the thus coated carrier film from said coating station through a drying station and drying said first and second coating layers; directing the thus coated and dried carrier film through a coating station; depositing onto the surface of the dried second coating layer a third coating layer of a solvent based primer composition; depositing onto the third coating layer a fourth coating layer of a solvent based adhesive composition; and directing the thus coated film from said coating station through a drying station and drying said third and fourth coating layers. Preferably, the first two depositing steps are performed during a first pass through said coating station, and the second two depositing steps are performed during a second pass through the same coating station.
[0008] In one embodiment the depositing steps are carried out by directing the carrier film past first and second successively arranged coaters which are mounted adjacent a cylindrical coating roll. The carrier film is guided onto the coating roll and the roll is rotated to advance the film while on the coating roll successively past the first and second coaters for depositing the first and second coating layers. In one preferred embodiment, the first and second coaters comprise respective slot coating dies mounted at spaced locations along the circumference of the coating roll. In another preferred embodiment, the first and second coaters comprise a multi-slot coating die mounted adjacent the coating roll.
[0009] The present invention also provides an apparatus for making a decorative sheet material comprising: a coating station having first and second coaters; means for supplying to the first coater of said coating station a solvent based clear coat composition; means for supplying to the second coater of the coating station a solvent based pigmented color coat composition; an unwind stand for receiving a roll of flexible carrier film; means for directing the flexible carrier film from the unwind stand through the coating station and successively past the first and second coaters for forming a first coating layer of clear coat composition on the surface of said carrier film and a second coating layer of pigmented color coat composition on the first coating layer; a drying station positioned adjacent the coating station to receive the thus coated film from the coating station and to dry said first and second coating layers; and a windup stand positioned for receiving the coated and dried film from the dryer and for winding the same into a roll. In one embodiment, the coating station includes a rotatably mounted cylindrical coating roll mounted for receiving the carrier film, and wherein first and second coaters are mounted adjacent said coating roll and successively arranged so that rotation of the coating roll advances the carrier film while on the coating roll successively past the first and second coaters for depositing the first and second coating layers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
[0011] [0011]FIG. 1 is a schematic illustration of an apparatus for making multilayered decorative sheet materials in accordance with the present invention;
[0012] [0012]FIGS. 2 and 3 are cross-sectional views of intermediate products produced on the apparatus of FIG. 1;
[0013] [0013]FIG. 4 is a cross-sectional view of a decorative sheet material in accordance with the invention;
[0014] [0014]FIG. 5 is a schematic illustration of an arrangement of apparatus utilized in the manufacture of the decorative sheet material of FIG. 4;
[0015] [0015]FIG. 6 is a cross-sectional view showing a substrate to which the decorative sheet material of FIG. 4 has been applied;
[0016] [0016]FIG. 7 is a schematic illustration of a portion of the coating apparatus configured in accordance with an alternate embodiment of the present invention;
[0017] [0017]FIGS. 8, 9 and 10 are cross-sectional views of decorative sheet material products produced in accordance with the present invention;
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
[0019] [0019]FIG. 1 illustrates a coating apparatus 10 which can be utilized in the manufacture of decorative sheet materials in accordance with the present invention. As shown, the apparatus includes an unwind stand 11 in which is mounted a roll 12 of flexible carrier film 13 . The carrier film 13 has low elongation or extensibility and preferably comprises a polyester casting film. For high gloss applications, the carrier film 13 should have a high gloss surface because it imparts high gloss and DOI to the decorative sheet material. Advantageously for high gloss applications, the carrier film 13 comprises polyethylene terephthalate (PET) in a grade without internal fillers. The carrier film 13 is about 1 to about 3 mils in thickness, preferably about 2 mils in thickness. The film 13 is unwound from the roll 12 by a cooperating pair of rolls 14 and is directed to a coating station generally indicated at 15 . The coating station 15 includes a cylindrical coating roll 16 and at least two coaters mounted adjacent the coating roll. In the embodiment illustrated, a first coater 17 is mounted adjacent one side of the coating roll and a second coater 18 is mounted diametrically opposite the first coater. In the embodiment shown, both the first and second coaters 17 and 18 comprise slot die coaters. However, it should be understood that the present invention in its broad aspects could utilize various other conventional coaters such as notched (comma) coaters, knife over roll coaters and blade coaters.
[0020] If a single pigmented layer is used as the decorative paint film, the pigmented layer is deposited onto the carrier film 13 using either of the first or second coaters 17 , 18 . In the embodiment illustrated, however, a base coat/clear coat type of product is to be produced and the two coaters are used for applying the two coating layers. More specifically, a suitable solvent based coating composition is supplied to the first coater 17 via a pipeline from a first supply tank 21 and a suitable solvent based coating composition for the second coater 18 is supplied from a second supply tank 22 . The carrier film 13 advances from the rolls 14 around a guide roll 23 and is directed onto the outer surface of coating roll 16 . Coating roll 16 rotates as indicated as by the arrow, thereby advancing the carrier film 13 successively past the first coater 17 where a uniform thin film layer 34 (FIG. 2) of solvent based coating composition is deposited onto the surface of the carrier film. The carrier film then advances past the second coater 18 where a second thin film layer 35 (FIG. 2) of coating composition from the second supply tank 22 is deposited onto the undried first layer 34 (FIG. 2) of coating composition.
[0021] The film 13 with the wet or undried coating layers 34 , 35 (FIG. 2) thereon then advances around a turning roll 24 and is directed into and through an elongated drying oven 25 . The oven is heated in a conventional manner, preferably by forced hot air. As the film is heated, the solvents in the coating layers are evaporated and the coating layers are dried. The solvent vapors are recovered by a conventional solvent recovery system 26 or destroyed by an ecologically sound and approved method. Preferably the drying oven 25 has multiple heating zones wherein each successive heating zone operates at a progressively higher temperature. For example, an oven having four to six heating zones ranging in temperature from about 200° F. to about 400° F. may be used.
[0022] Upon emerging from the drying oven 25 , the thus formed intermediate film product 27 passes around a turning roll 28 . The film product 27 then passes around the upper one of a pair of cooperating rolls 30 , 31 which form a nip and serve to advance the carrier film 13 in its path of travel and to maintain it at a suitable tension for processing and handling. Upon leaving the nip rolls 30 , 31 , the film is wound into a roll 32 at a windup stand 33 .
[0023] [0023]FIG. 2 shows the cross section of the intermediate film product 27 produced as just described by directing an uncoated carrier film 13 through the coating apparatus 10 and forming first and second coating layers 34 , 35 thereon. The particular intermediate film 27 product shown in FIG. 2 is used in the manufacture of a base coat/clear coat type of paint film. Consequently, the first coating layer 34 is produced from a solvent based clear coat composition and the second coating layer 35 is produced from a solvent based pigmented color coat composition. The clear coat of the first coating layer 34 is formed from a substantially transparent weatherable polymer composition selected to provide a film that will not significantly fade, peel, crack, or chalk when exposed to the environment for the intended life of the film. Additionally, the clear coat layer must be formable from a two-dimensional surface to a three-dimensional surface without objectionable loss of appearance or performance properties. Advantageously, the clear coat layer is selected from the group consisting of urethane polymers, acrylic polymers, fluoropolymers, and alloys of a fluoropolymer and an acrylic polymer (such as FLUOREX® films). The clear coat layer may include UV screeners, antioxidants, heat stabilizers, and other conventional additives. Preferably, the clear coat layer is about 0.3 to about 3 mils in thickness.
[0024] The second coating layer 35 , which is applied at the second coater 18 , forms the color coat layer of the paint film and is formed of a polymer composition containing a uniformly dispersed pigment to provide the appearance necessary for exterior automobile use. Preferably, the color coat composition is selected from the group consisting of urethane polymers, acrylic polymers, fluoropolymers, and alloys of a fluoropolymer and an acrylic polymer (such as FLUOREX® films). The color coat layer may include additional pigments, dyes and/or flakes to enhance visual appearance and improve weatherability. Preferably, the color coat layer is about 0.3 to about 3 mils in thickness.
[0025] The roll 32 of intermediate film product 27 , produced as described above, may now be directed through the coating apparatus of FIG. 1 for a second pass during which two additional coating layers 37 , 38 (FIG. 3) of primer and adhesive, respectively, are deposited and a thermoformable backing layer 39 (FIG. 3) is laminated to the thus-formed multi-layer film product to produce a thermoformable film product 40 . Thus, after its second pass through the coating apparatus 10 , the multilayer thermoformable decorative sheet material product 40 has a cross section similar to that shown in FIG. 3, and includes the carrier film 13 , the clear coat layer 34 , the pigmented color coat layer 35 , a primer layer 37 , an adhesive layer 38 , and a thermoformable backing layer 39 . The thermoformable backing layer 39 provides bulk and/or rigidity for handling the decorative sheet material as a thermoformed preform. The backing layer also provides thickness to prevent glass fibers, fillers or other sources of visual roughening or “orange peel” from the underlying substrate from affecting the visual appearance of the decorative sheet material. The backing layer must bond well with both the substrate and the adhesive layer 38 . The backing layer may be selected from the group consisting of thermoplastic olefin (TPO), acrylonitrile-butadiene-styrene (ABS) terpolymer resin, polypropylene, thermoplastic polyamide, polyethylene oxide, polycarbonate, polyvinyl chloride, polystyrene, styrene/polyphenylene oxide (NORYEL), polybutylene terephthalate, nylon, PETG copolyester, and mixtures, laminates and copolymers thereof, depending on the material used as the substrate.
[0026] The coating apparatus 10 as used during the second coating pass is configured substantially as is shown in FIG. 1. As shown by dotted lines in FIG. 1, the thermoformable backing layer 39 is advanced from a supply roll and is directed into the nip and into contact with the adhesive layer 38 present on the advancing multilayer product. After passing through the nip, with suitable application of pressure and heat, the multilayer thermoformable decorative sheet material product 40 is produced. The product 40 is taken up in the form of a roll for subsequent handling and processing.
[0027] During the second pass through the coating apparatus 10 , a primer layer 37 is formed on the pigmented color coat layer 35 at the first coater 17 and an adhesive layer 38 is formed on the undried primer layer 37 at the second coater 18 . The primer layer 37 improves adhesion between the color coat layer 35 and the adhesive layer 38 . The primer layer 37 preferably comprises acrylic polymer prepared in solution using any compatible solvent known in the art, such as toluene. In one embodiment, the primer layer 37 is prepared from a solution comprising about 20 to about 40 weight percent acrylic composition and about 60 to about 80 weight percent solvent. An acrylic polymer suitable for use in the primer layer 37 is acrylic adhesive 68070 manufactured by DuPont. The primer layer 37 may be opaque, colored or clear. The primer layer 37 is preferably about 0.2 to about 2 mils in thickness. The primer layer 37 may be colored or opaque to protect an underlying thermoformable backing layer from damage caused by UV exposure. Pigments, such as carbon black, titanium oxide, and mixtures thereof may be added to impart color to the acrylic polymer composition used in the primer layer. Additionally, additives such as UV screeners, antioxidants and heat stabilizers may be added to the composition of the primer layer 37 .
[0028] The adhesive layer 38 is provided for adhering the decorative paint film to a thermoformable backing layer 39 . The adhesive layer 38 comprises one or more layers selected from the group consisting of urethane adhesives, acrylic adhesives, acrylic adhesives with cross linkers, chlorinated polyolefins and mixtures thereof. Preferably, a mixture of a chlorinated polypropylene and a higher molecular weight chlorinated polyolefin is used. In one embodiment, the adhesive layer 38 is prepared from a mixture of about 5 to about 20 weight percent chlorinated polypropylene and about 1 to about 10 weight percent of a higher molecular weight chlorinated polyolefin formed in solution. A compatible solvent known in the art, such as toluene, is present in an amount of about 60 to about 80 weight percent. A chlorinated polypropylene suitable for use with the present invention is HARDLEN 13LP manufactured by Advanced Polymer. A higher molecular weight chlorinated polyolefin suitable for use with the present invention is SUPERCHLON 822S manufactured by CP/Phibrochem of Fort Lee, N.J. The adhesive layer 38 should be capable of stretching about 300 to about 600 percent. Due to the substantial elongation capability of the adhesive layer 38 , the adhesive layer maintains the necessary adhesive strength to prevent delamination of the decorative paint film from the thermoformable backing layer 39 over a wide temperature range.
[0029] An epoxy component, such as EPON 828RS manufactured by Shell Chemical, may be added in small amounts (approximately about 0.1 to about 2.0 weight percent on a dry solids basis) as an acid scavenger. As with the primer layer 37 , the adhesive layer 38 may be colored or opaque to protect the underlying thermoformable backing layer from damage caused by UV exposure. Pigments, such as carbon black, titanium oxide, and mixtures thereof, may be added to impart color to the polymer composition used in the adhesive layer 38 . Additives such as UV screeners, antioxidants, and heat stabilizers may be added to the adhesive layer 38 . Preferably, the adhesive layer 38 is about 0.2 to about 2 mils in thickness.
[0030] In a subsequent operation, the coating apparatus 10 , with minor modifications, may be utilized to produce an extensible mask layer 41 and to laminate the mask layer 34 to the clear coat layer 34 of the multilayer thermoformable decorative sheet material product 40 ′. The resulting end product is shown in cross section in FIG. 4. It is intended that the carrier layer 42 be removed prior to thermoforming.
[0031] The coating apparatus 10 is shown in FIG. 5 as it would be configured for manufacturing the extensible mask layer 41 and for laminating it to the multilayer thermoformable decorative sheet material product 40 . To avoid repetitive description, elements of the coating apparatus 10 which are the same as in the FIG. 1 configuration are identified by the same reference characters, and elements which are different will be identified by different reference numbers. As shown in FIG. 5, another flexible carrier film 42 is unwound from a roll 43 and is directed to the coating station 15 . The flexible carrier film 42 has low elongation and extensibility. One suitable film for this purpose is a polyester film, and a polyethylene terephthalate (PET) film is particularly preferred. The carrier film 42 is about 1 to 3 mils in thickness, preferably about two mils in thickness and it may comprise a film with high gloss and no slip additives or a film containing slip additives can be suitably used if desired.
[0032] Preferably, the extensible mask layer 41 is about 0.3 mils to about 3.0 mils in thickness. The extensible mask layer includes a film-forming polymer component. Preferably, the film-forming component is selected from the group consisting of polyurethane, polyolefin, polyester, polyamide, and mixtures thereof. In one embodiment, the film-forming polymer component comprises an aliphatic or aromatic polyester or polyether polyurethane in the form of a dispersion or a solution. For example, polyurethane polymers QA 5218 and QA 5026, manufactured by Mace Adhesives and Coatings of Dudley, Mass., may be used to form the mask layer 41 . In one embodiment, the mask layer 41 comprises about 85 to about 99.5 weight percent polyurethane water-borne dispersion. Advantageously, a small amount of surfactant (about 0.05 to about 0.2 weight percent), such as SURFYNOL 104H manufactured by Air Products of Allentown, Pa., is added to lower surface tension.
[0033] The mask layer 41 may optionally contain a particulate filler dispersed in the film-forming polymer component for the purpose of controllably altering the gloss of the paint film. The particulate filler is preferably selected from the group consisting of fumed silica, talc, calcium carbonate, clay, alumina, and mixtures thereof. However, other particulate fillers that are compatible with the film-forming polymer component may be used without departing from the present invention. Advantageously, the particulate filler is chemically inert. In one embodiment, the particulate filler dispersed in the polymer component is present at a concentration sufficient to controllably alter the gloss appearance of the underlying paint film after forming and upon removal of the mask layer. The concentration of the particulate filler will depend largely on the desired gloss of the final product. Different levels of particulate filler may be utilized in order to produce different levels of gloss reduction in the final product. A greater concentration of particulate filler in the mask layer 41 will generally provide a lower final gloss value in the resulting paint film. For example, if only relatively slight reduction in gloss is desired, the particulate filler may be present in the mask layer at a concentration of about 0.5 weight percent of the mask layer on a dry solids basis.
[0034] The mask layer 41 composition may include additional additives designed to migrate into the clear coat layer 34 to enhance weatherability or other desirable properties of the clear coat layer or to prevent migration of additives from the clear coat into the mask layer. Migratory additives suitable for use with the present invention include, but are not limited to, hardness enhancers, release agents, ultraviolet light stabilizers, antioxidants, dyes, lubricants, surfactants, catalysts, and slip additives.
[0035] More specifically, the migratory additives useful in the present invention include benzophenone, silicones, waxes, triazoles, triazines and combinations thereof. The migratory additives are encouraged to migrate into the outer surface of the clear coat layer 34 by the heat and/or pressure present during thermoforming or molding processes. Additionally, the presence of these additives in the mask layer 41 prevents migration of additive components from the clear coat layer 34 into the mask layer.
[0036] Ultraviolet light stabilizers, such as TINUVIN 1130 and TINUVIN 292, both manufactured by Ciba Geigy of Hawthorne, N.Y., can be added as migratory additives in the mask layer composition. Silicone additives, such as BYK333 manufactured by BYK Chemie of Wallingford, Conn., can be added to lower the coefficient of friction of the clear coat layer 34 . The migratory additives are generally added in amounts ranging from about 0.01 to about 2.0 weight percent, with all additives accounting for no more than about 5.0 weight percent of the mask layer composition.
[0037] The flexible carrier film 42 is advanced through the coating station 15 and a film-forming polymer composition for producing the mask layer 41 is applied to the carrier film. The composition can be applied using one or both of the coaters 17 , 18 . The coated carrier film 42 is advanced through the drying oven 25 and the coating is dried, resulting in the formation of an extensible mask layer 41 releasably adhered to the carrier film 42 .
[0038] The previously produced roll of multilayer thermoformable decorative sheet material product 40 is mounted at an unwind stand 50 located adjacent to the cooperating nip rolls 30 , 31 . Preferably, at least one of the rolls 30 and 31 is heated. The multilayer thermoformable decorative sheet material product 40 has the carrier film 13 side located outermost and the thermoformable backing layer side 39 facing inwardly. As the sheet material product 40 is advanced upwardly from the roll, the carrier film 13 is stripped free from product 40 by turning around a sharp angle over a turning rod 47 , thereby exposing the clear coat layer 34 . As the mask layer 41 and flexible carrier 42 pass through the nip, the mask layer 41 is brought into contact with the exposed clear coat layer 34 of the decorative sheet material product 40 and is releasably bonded to the clear coat layer 34 under the heat and pressure of the nip. The resulting composite sheet material 40 ′ (FIG. 4) is taken up in the form of a roll 48 . In subsequent use, the flexible carrier 42 is removed from the product.
[0039] The composite multilayer decorative sheet material 40 ′ can be combined with a substrate material to form a decorative outer surface for the substrate. For example the material 40 ′ can be bonded to an already produced substrate. Alternatively, the sheet material 40 ′ can be utilized in an in-mold surfacing operation. In this case, the sheet material 40 ′ can be formed into a three dimensional configuration, placed within a mold, and the substrate material can be injection molded behind the preformed sheet material 40 ′ and becomes fused or bonded to the thermoformable backing layer to form a composite shaped part. FIG. 6 shows a greatly expanded cross sectional view of a molded part comprising the decorative sheet material 40 ′ adhered to a substrate 53 formed by injection molding.
[0040] The extensible mask layer 41 is provided to assist in controlling the gloss and DOI during forming processes and molding processes. Forming processes include, but are not limited to, thermoforming, cold stretching and vacuum forming. Molding processes include, but are not limited to, injection molding, compression molding and blow molding. The mask layer 41 also adds strength to the decorative sheet material and improves process uniformity during the thermoforming process. Additionally, the mask layer protects the underlying layers of the decorative sheet material from scratching or marring until the part is ready for display. The mask layer is capable of stretching up to about 600% during thermoforming and has a room temperature elongation at break of at 20 least about 200 %. Room temperature is defined as about 15° C. to about 30° C.
[0041] The mask layer 41 may be retained as the outer layer of the decorative sheet material during construction of the final product, such as an automobile. Thereafter, the mask layer may be removed to reveal the underlying decorative paint film. For instance, the extensible mask layer can be maintained as a protective layer and removed only after the vehicle has completed shipment and is ready for delivery to a customer. The extensible mask layer is releasably bonded to the underlying decorative paint film and may be stripped away from the underlying layers in a single piece. In a preferred embodiment, the mask layer is transparent or substantially transparent to permit visual inspection of the part for surface defects without removal of the mask layer.
[0042] Additionally, the extensible mask layer maintains uniform gloss and DOI during injection or compression molding, such as thermoplastic or thermoset compression molding, where the mold is roughened or deglossed. Roughened molds are less expensive than highly polished molds and are also functionally superior to highly polished molds because the rough mold surface enhances air removal from the mold as the mold closes. The extensible mask layer protects the paint film from damage caused by the mold without resorting to the use of highly polished molds.
[0043] [0043]FIG. 7 illustrates an alternate form of the coating station. To avoid repetitive description, parts in FIG. 7 which correspond to those previously discussed in connection with FIG. 1, will be identified by the same reference numbers with prime notation added. As can be readily seen from comparing FIGS. 1 and 7, the coating station 15 ′ of FIG. 7 is similar in many respects to that of FIG. 1. The principal difference is that the second coating station 18 ′ is a dual slot die coater comprising two slots extended substantially parallel to one another. The two slots of the die 18 ′ are supplied with coating composition from respective supply tanks 22 ′, 22 a ′. Thus, with this configuration of apparatus, it is possible to apply three coating layers wet-on-wet in a single pass. Depending upon the coating compositions supplied to the dual slot die 18 ′ and the configuration of the slots, various unique products can be produced.
[0044] [0044]FIG. 8 illustrates one such product which can be produced during the first pass of the carrier film 13 through the coating station. In this product, a clear coat composition 34 is applied at the first coating station 17 ′ as in the FIG. 1 embodiment. At the second coater 18 ′, a color adjusting layer 54 is applied from the first of the two successively arranged slots and a pigmented color coat layer 35 is applied from the second slot.
[0045] [0045]FIG. 9 shows still another product configuration whereby a two-tone striped appearance can be produced in a single pass through the coating station 15 ′. In this arrangement, the two slots of the dual slot die coater 18 ′ are blocked along a portion of their length and are open along the remaining portion of their length. As in the previous embodiment, the first coater 17 ′ applies a clear coat composition. The dual slot die applies two pigmented coating compositions of different colors. Thus, a first pigmented coating composition 35 a is applied over a portion of the width of the advancing sheet material from the first slot and a second coating composition 35 b of a different color is applied over the remaining portion of the width of the sheet material from the second slot. The resulting sheet material has a striped or two-tone appearance. The dual slot die arrangement has several advantages over known slide coating or cascade coating techniques. It eliminates viscous flow down the slide and the problem of drying on the slide, and it provides the capability of a broader viscosity and thickness range.
[0046] [0046]FIG. 10 illustrates another product configuration which may be produced with the process and apparatus of the present invention. This product 40 ″ is similar to the product 40 of FIG. 3 described above, except that instead of a separate color coat 35 and primer coat 37 the primer coating composition has color and serves as both the color coat layer and the primer. This combined color and primer coat layer 35 ′ contains pigments and optionally also reflective flakes, depending upon the color appearance desired. Using an apparatus configured as in FIG. 1, the clear coat layer 34 and the pigmented primer coat layer 35 ′ may be successively applied to the carrier film 13 and thereafter dried to form the intermediate film product 27 . In a subsequent pass through the apparatus, an adhesive layer 38 and backing layer 39 can be applied to the intermediate film product 27 to produce the multilayer thermoformable decorative sheet material product 40 ″. The backing layer 39 may either be laminated to the adhesive coated intermediate film product, or alternatively, the backing layer may be applied by extrusion coating a thermoplastic polymer layer directly onto the adhesive-coated intermediate film product.
[0047] Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. | An apparatus and method of making a decorative sheet material is provided whereby complex multi-layer films are produced with enhanced efficiency and assurance of quality. The method involves directing a flexible carrier film through a coating station; depositing onto the surface of the carrier film a first coating layer of a solvent based clear coat composition; depositing onto the first coating layer a second coating layer of a solvent based pigmented color coat composition; directing the thus coated carrier film from said coating station through a drying station and drying said first and second coating layers; directing the thus coated and dried carrier film through a coating station; depositing onto the surface of the dried second coating layer a third coating layer of a solvent based primer composition; depositing onto the third coating layer a fourth coating layer of a solvent based adhesive composition; and directing the thus coated film from said coating station through a drying station and drying said third and fourth coating layers. Preferably, the first two depositing steps are performed during a first pass through said coating station, and the second two depositing steps are performed during a second pass through the same coating station. | 8 |
PRIORITY
This application claims priority from Canadian Patent Applications 2,768,359 and 2,769,060 each filed Feb. 17, 2012.
FIELD OF THE INVENTION
The invention generally relates to a chemical processes used in processing recovered gas and oil, and more particularly to a process and apparatus for the removal of sulfur compounds from gas streams.
BACKGROUND
Natural gas and refinery gas streams are commonly contaminated with sulfur-containing compounds such as hydrogen sulfide (H 2 S) and/or carbonyl sulfide (COS) and carbon dioxide (CO 2 ). If substantial amounts of H 2 S are present, regulatory restrictions dictate special precautions must be taken to purify the gas streams. The first step of the H 2 S removal process from the H 2 S-containing streams is accomplished by an acid-gas removal unit which removes substantial amounts of H 2 S and CO 2 from the acidic-gas containing streams. The off-gas from the acid-gas removal unit is mainly H 2 S and CO 2 . The sulfur from this off-gas stream is usually removed by the Claus reaction which produces salable elemental sulfur. After a ‘tail-gas’ treatment to further reduce the sulphur content, the remaining CO 2 may be safely vented to the atmosphere. However, there has been increasing concern about the damage caused by CO 2 and this has led to an increased demand to reduce the emission of CO 2 to the atmosphere.
Typically, separation of CO 2 and H 2 S from streams containing acidic gas is achieved by the chemical absorption process employing liquid amine solutions, such as monoethanolamine (MEA), diethanolamine (DEA) or methyldiethanolamine (MDEA). In this process the CO 2 reacts with the liquid amine solution to form a carbamate, while H 2 S reacts with the amine solution to form (amine)H + and bisulfide (SH − ) species. Upon heating, the carbamate and (amine)H + species decompose to release the absorbed CO 2 and H 2 S and produce a regenerated amine solution. Disadvantageously with this process, however, sulfur-containing compounds such as SO 2 , COS and/or CS 2 , if present in the feed stream, react with the liquid amine absorbent and a higher temperature is required to regenerate the amine solution. SO 2 also reacts with the amine to form sulphates which necessitates partial replacement of the amine.
Liquid alkoxylated amines, such as diisopropanolamine, have been used for CO 2 removal from streams containing acidic gases. U.S. Pat. No. 4,044,100 described the use of liquid mixtures of diisopropanolamine and polyethylene glycol for acid gas removal from gaseous streams.
There are many fields of applications in which it is required to remove H 2 S and CO 2 from streams containing acidic gases. U.S. Pat. No. 4,553,984 describes a process for the removal of CO 2 and H 2 S, simultaneously, from streams containing acidic gases wherein the stream is brought into counter flow contact with an aqueous of methyldiethanolamine (MDEA) at a pressure of 10-110 bars. Nevertheless, there are different applications in which it is required to reduce the H 2 S to a very low level without essential removal of CO 2 ; therefore, solvents with high H 2 S-absorbing power are desired. U.S. Pat. No. 5,277,884 disclosed a process for selective removal of H 2 S from streams containing both H 2 S and CO 2 acidic gases. The process according to that invention comprises contacting the acidic gas containing stream with a solvent that comprises a mixture of N-methylpyrrolidone (NMP) and dodecane.
The acid gas removal process utilizing liquid amine solutions is costly and energy-intensive because the liquid amine solution has a limited life time due to its degradation through oxidation. Furthermore, the high corrosivity of the utilized amine makes it prohibitive to use high concentrations of the amine solutions. Therefore, new acidic gas capture technology utilizing thermally stable solid sorbents has increasingly received attention due to its potential for reducing corrosion and energy cost and improving mass/heat transfer efficiency. Such technology is based on the ability of a porous solid sorbent to reversibly adsorb the CO 2 and H 2 S from the acidic gas containing streams at high pressure.
U.S. patent application Ser. No. 13/399,911 filed Feb. 17, 2012 relates to a process for a acidic gas recovery from acidic gas containing streams employing a class of novel thermally stable amine adducts (sorbents). The regenerable sorbents described in that process had high CO 2 and H 2 S absorption capacity and comprised a porous solid support, a cross-linked amine and a polyol reactive toward the utilized amine. The sorbents according to this invention enable acidic gas absorption/desorption cycles at various temperatures and pressures. Advantageously, the absorption/desorption cycles could be conducted at a pressure of 1500 psig and a temperature of 130° C., so that the CO 2 at this condition was ready for direct downhole storage or pipelining at greatly reduced compression costs. In addition the adsorption could take place at low pressure with desorption at high pressure.
Typically, the desorbed gas stream from an acid-gas removal unit is mainly H 2 S and CO 2 and the sulfur is usually removed by the Claus process. In the first step in the Claus process, one third of the hydrogen sulfide present in the feed stream is oxidized to sulfur dioxide, SO 2 , by the reaction as follows:
H 2 S+O 2 =SO 2 +H 2
In the second step, the remaining H 2 S and the SO 2 are reacted in the presence of a Claus catalyst to form elemental sulfur in a Claus reactor according to Reaction 1:
2H 2 S+SO 2 =2H 2 O+3S Claus reaction 1.
The Claus reaction is limited by thermodynamic equilibrium and only a portion of the total sulfur can be produced. Therefore, multiple stages with sulfur condensation between the stages are needed in order to increase the sulfur recovery factor. The effluent gas from a series of reactors in a Claus plant contains varying amounts of different compounds including sulfur vapor, sulfur dioxide, un-reacted H 2 S, carbonyl sulfide (COS), and/or carbon disulfide (CS 2 ). Carbon disulphide is formed according to Reaction 2:
CH 4 +4S→CS 2 +2H 2 S High temperature Claus furnace or combustion reaction 2.
Removal of the sulfur content of the off-gas streams from the Claus process is accomplished by catalytic reduction with hydrogen to convert the sulfur compounds to H 2 S, absorption of the H 2 S produced with an additional amine system and then recycling the desorbed gas to the Claus plant. This process is operable as long as the concentration of the CO 2 is up to 15% and H 2 S is above 50% by volume in the feed stream. However, if the H 2 S/CO 2 feed gas stream to Claus process contains less than 40% by volume H 2 S, the Claus plant becomes difficult to operate with respect to the thermal zone and special considerations have to be taken when combusting part of H 2 S to SO 2 as required for the Claus reaction. These operational difficulties mainly arise from the fact that the required temperatures for the combustion of H 2 S cannot be reached in the thermal zone. Therefore, the off-gas stream from the Claus plant is burned with air to convert all sulfur-containing compounds in the stream to SO 2 before discharge into the atmosphere. As the environmental requirements are becoming stricter, the SO 2 emission limit is being lowered, giving rise to the challenge of how to reduce or completely eliminate SO 2 emissions. Consequently, another sulfur removal process is needed that can handle H 2 S/CO 2 feed gas streams containing CO 2 of concentrations greater than 15% and H 2 S of a concentration less than 40% by volume.
The direct oxidation of H 2 S to elemental sulfur using oxidation catalysts has gained broad acceptance for achieving high sulfur removal efficiency. U.S. Pat. No. 4,197,277 describes a process for the oxidation of H 2 S to elemental sulfur by the following H 2 S Oxidation Reactions 3 and 4 :
H 2 S+0.5O 2 →S+H 2 O H 2 S Partial oxidation 3.
H 2 S+1.5O 2 →SO 2 +H 2 O H 2 S Complete oxidation 4.
According to U.S. Pat. No. 4,197,277, the H 2 S-containing gas is passed with an oxygen-containing gas over a catalyst which comprises iron oxide and vanadium oxide as active materials and aluminum oxide as a support material. The catalyst described in that Patent gives rise to at least a partial Claus equilibrium, so that SO 2 formation cannot be prevented. Similarly, U.S. Pat. No. 5,352,422 describes a process for oxidizing the un-reacted H 2 S in the Claus tail gas to elemental sulfur. The patent describes a catalyst prepared by impregnation of an iron containing solution or an iron/chromium-containing solution into several carriers followed by calcinations in air at 500° C.
U.S. Pat. No. 4,818,740 disclosed a catalyst for the H 2 S oxidation to elemental sulfur, the use of which prevents the reverse Claus reaction to a large extent. The catalyst according to that patent comprises a support of which the surface exposed to the gaseous phase does not exhibit any alkaline properties under the reaction conditions, while a catalytically active material is applied to this surface. An improvement of the method disclosed in '740 is disclosed in European Patent 409,353. This patent relates to a catalyst for the selective oxidation of sulfur-containing compounds to elemental sulfur, comprising at least one catalytically active material and optionally a support. The described catalyst exhibits substantially no activity towards the reverse Claus reaction under the reaction conditions.
The H 2 S direct oxidation to elemental sulfur is suitable for gas streams comprising high concentrations of CO 2 and low concentrations of H 2 S. Nevertheless, the total sulfur removal efficiency decreases if carbon monoxide or COS gases are present in the feed stream. Carbon monoxide, if present in the feed gas streams, undergoes side reactions during the H 2 S direct oxidation to form COS. In addition, CO 2 may also react with H 2 S to form COS during direct oxidation reaction:
CO+S→COS 5.
CO+H 2 S→COS+H 2 6.
3CO+SO 2→COS+ 2CO 2 7.
H 2 S+CO 2 →COS+H 2 O 8.
U.S. patent application Ser. No. 13/399,710 filed Feb. 17, 2012 entitled “Removal of Sulfur Compounds from a Gas Stream” relates to a process for simultaneously oxidizing H 2 S to elemental sulfur and hydrolyzing COS to H 2 S in the presence of an oxidation catalyst and a feed gas stream containing CO of a concentration greater than 1% by volume and CO 2 of a concentration greater than 14% by volume of the total feed gas flow. In this process, an H 2 S-containing stream was mixed with a molecular oxygen containing gas and then passed over an oxidation catalyst at a temperature of 220° C., a gas hourly space velocity of 1000 hr −1 and a pressure of 100 psig. The concentration of the COS produced decreased from 1900 ppm, using a dry gas stream, to 316 ppm upon using a feed stream containing greater than 10% water. The oxygen in the feed gas stream was adjusted to achieve the highest conversion of H 2 S to elemental sulfur and to deliberately produce an off-gas stream containing H 2 S/SO 2 ratio of 2:1 which is ready as a feed gas stream for other sulfur removal units such as Crystasulf™ 1 . Therefore, the process was operated at a relatively low sulfur yield of 78.1% and a total H 2 S conversion of 90.4%. 1 Trademark of URS CORPORATION for sulfur removal units.
In summary, high sulfur removal efficiency can be achieved by utilizing a multi-stage Claus process and off-gas post treatment. Importantly, however, this process is limited by the concentration of the CO 2 in the gas stream and necessity of employing an H 2 S enrichment unit. Therefore, other sulfur recovery processes, such as the H 2 S direct oxidation process, have gained worldwide attention. In fact, the H 2 S direct oxidation to elemental sulfur process has become the cornerstone of the high sulfur recovery upon coupling with Claus process. Disadvantageously, however, the H 2 S direct oxidation process is still limited due to the process conditions and feed gas composition. As mentioned, a considerable amount of COS is produced when operating the H 2 S direct oxidation process, in a once-through mode, with sulfur-containing gas streams comprising CO and CO 2 at a temperature above the sulfur dew point and a high pressure. Consequently, a robust sulfur removal process that can overcome the aforementioned difficulties is still needed.
SUMMARY OF THE INVENTION
The present invention provides a robust process for the efficient carbon dioxide recovery and desulfurization of feed stream gases comprising sulfur constituents as well as a considerable amount of carbon dioxide at elevated pressure, including but not limited to CO 2 of a concentration greater than 14% by volume of the total feed gas flow.
The process according to this invention not only converts the sulfur-containing compounds to elemental sulfur but also produces a high pressure CO 2 stream of high purity. This process will remarkably reduce the size of the reactor required for the desulfurization of the feed streams and will also provide a significant energy consumption advantage when the CO 2 gas stream is compressed for pipelining or deep well disposal. The feed streams suitable for the process according to the present invention comprise but are limited to sulfur containing compounds, such as H 2 S, SO 2 , COS, CS 2 ; oxidizable constituents such as, hydrogen, carbon monoxide, light hydrocarbons, e.g. methane, ethane or propane; natural gas; associated gas from oil production; gases produced from oilsand refining, e.g. coker gas; gases produced from Toe-to-Heel-Air-Injection process (THAI™); or other in situ combustion gas; coal or oil gasification processes; inert gases, such as nitrogen, helium or carbon dioxide and any combination thereof.
The approach utilized in the present invention is to selectively remove and concentrate the H 2 S and/or CO 2 from the gas streams, and then oxidize the H 2 S to salable elemental sulfur. More particular, this invention comprises a process for the removal of H 2 S and/or CO 2 from the sour gases at room temperature and elevated pressure by contacting the sour gas with a suitable acid gas absorbent. Then, subjecting the absorbent to a desorption mode at a pressure similar to the absorption pressure but at an elevated temperature. The produced gas stream from the desorption mode contains mainly H 2 S, CO 2 and/or N 2 . Subsequently, the product gas from the desorption mode is mixed with a stream containing molecular oxygen and is then passed to an H 2 S direct oxidation reactor to partially oxidize the H 2 S to elemental sulfur.
Accordingly, in one broad aspect of the method of the present invention, such method comprises a method of reducing the amount of sulfur compounds in an incoming gas stream comprising:
a. providing a guard bed containing an hydrolysis catalyst for the conversion of COS and CS 2 to H 2 S and the reduction of SO 2 to elemental sulfur, and optionally also an RSH adsorbent suitable for RSH removal; b. flowing said incoming gas stream through said guard bed to produce an effluent stream; c. providing an acidic gas removal unit comprising an absorbent suitable for acidic gas absorption; d. flowing said effluent stream from the guard bed over said absorbent in the acidic gas removal unit to produce a stream that is free of acidic gases, said absorbent becoming rich in acidic gases, e. applying an acidic-gas desorption condition to said acidic-gas rich absorbent to desorb acid gases from said absorbent and produce an acidic gas stream rich in acidic gases; f. introducing oxygen to said acidic gas-rich stream; g. providing a direct oxidation vessel containing a catalytic reaction zone comprising a catalyst suitable for catalyzing the oxidation of the H 2 S to sulfur wherein the temperature of the reaction zone is at or above the sulfur dew point at the reaction pressure; h. flowing said acidic gas-rich stream over said catalyst to produce a processed stream comprises a reduced level of said sulfur compounds when compared to the incoming effluent; and i. recycling at least a portion of said processed stream of reduced sulfur compounds back for passage through to said guard bed and acidic gas removal unit.
In a preferred embodiment, such process produces a pressurized stream of high CO 2 purity.
In a further embodiment, water is added to said incoming gas stream prior to delivery of said incoming gas stream to said guard bed.
In a further preferred embodiment, the sulfur compounds comprise one or more of COS, CS 2 , SO 2 , RSH and H 2 S.
In a further preferred embodiment, the RSH adsorbent comprises activated carbon.
In a further preferred embodiment, the hydrolysis catalysis includes one or more of alumina, titania or zirconia.
In a preferred embodiment of the above method, the guard bed is maintained in the range of from 20° C. to 300° C.
In a preferred embodiment of the above method, according to claim 1 wherein said absorbent suitable for acidic-gas removal includes physical or chemical solvents.
In a preferred embodiment of the above method, the physical or chemical solvents used as absorbents are in liquid form or supported on porous support.
In a still-further embodiment of the above method, the acidic-gas absorption or adsorption mode is conducted at a temperature below 100° C.
In a still further embodiment of the above method, the acidic-gas absorption or adsorption mode is conducted at a pressure of up to 1500 psig.
In a still-further preferred embodiment of the above method, the method comprises a desorption step wherein acidic gas is desorbed from the acidic gas absorbent.
In a still further preferred embodiment, the desorption step is conducted at a temperature at least 20° C. above the absorption or adsorption temperature.
In a still further preferred embodiment, the desorption step is conducted at a pressure up to 1500 psig.
In a still further preferred embodiment, the temperature of the reaction zone in the direct-oxidation vessel is in the range of 150° C. to 400° C.
In a still further preferred embodiment, the incoming gas stream to the direct oxidation vessel is at a gas hourly space velocity between 100 to 10,000 hr −1 .
In a still further preferred embodiment, the pressure in the reaction zone in the direct oxidation vessel is between 15 and 500 psig.
In another aspect of the present invention, the present invention relates to a system for reducing the amount of sulfur compounds in an incoming gas stream and producing a CO 2 stream of high purity. Accordingly, such system of the present invention, in a broad aspect thereof, comprises:
i. a guard bed containing an hydrolysis catalyst, said hydrolysis catalyst adapted for the conversion of COS and CS 2 to H 2 S and the reduction of SO 2 to elemental sulfur, and optionally also an RSH adsorbent suitable for RSH removal, said guard bed adapted to receive said incoming stream and produce an effluent stream after passage of said incoming stream through said guard bed; ii. an acidic gas removal unit comprising an absorbent suitable for acidic gas absorption, adapted to receive said effluent stream and produce a produced stream that is free of acidic gases, said absorbent becoming rich in acidic gases; iii. said absorbent adapted, when said having heat applied thereto, to produce an acidic gas stream rich in acidic gases; iv. oxygen supply means, adapted to supply oxygen to said acidic gas stream; v. a direct oxidation vessel, adapted to receive said acidic stream rich in acidic gases and oxygen, and containing a catalytic reaction zone comprising a catalyst suitable for catalyzing the oxidation of the H 2 S to sulfur wherein the temperature of the reaction zone is at or above the sulfur dew point at the reaction pressure, and to produce a processed stream comprising a reduced level of said sulfur compounds when compared to the incoming acidic stream; and vi. recycling piping to recycle at least a portion of said processed stream back to said guard bed and acidic gas removal unit.
In a preferred embodiment of the above system the sulfur compounds comprise one or more of COS, CS 2 , SO 2 , RSH and H 2 S.
In a further preferred embodiment of the system where an RSH adsorbent is used, such RSH adsorbent comprises activated carbon.
In a further preferred embodiment the hydrolysis catalysis includes one or more of alumina, titania or zirconia.
In a still further preferred embodiment, the absorbent suitable for acidic gas absorption comprises physical or chemical solvents for acidic-gas removal, and further wherein said physical or chemical solvents are in liquid form or supported on a porous support.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the desulfurization process of the present invention;
FIG. 2 is a schematic graph of the variation of H 2 S concentration in the recycle gas from the absorber column;
FIG. 3 is a schematic graph of the variation of H 2 S concentration in the recycle gas from the H 2 S direct oxidation reactor;
FIG. 4 is a schematic graph of the variation of COS concentration in the recycle gas from the H 2 S direct oxidation reactor; and
FIG. 5 is a schematic graph of the variation of SO 2 concentration in the recycle gas from the H 2 S direct oxidation reactor
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 , the overall chemical process of the present invention is shown as a flow diagram in which the components of the acid gas removal system apparatus 100 are shown.
According to the first step of the process, a sulfur-containing gas stream 2 , 3 , typically a sour gas stream comprising CO 2 and H 2 S, is fed to a primary absorber column 7 comprising an amine-based acid gas absorbent to remove the CO 2 and H 2 S from the sour gas stream.
Notably, however, different sulfur containing compounds such as COS, SO 2 and/or RSH, if present in the sour gas stream, will react with the amine-based absorbent, and reduce its CO 2 and H 2 S absorption capacity. Therefore, a protective guard bed 6 containing alumina and/or activated carbon at a temperature of 120° C. is placed on the feed gas stream prior to the primary amine absorber column 7 [and also prior to the secondary amine absorber column 7 a —see below]. The main function of the protective guard bed 6 , 6 a is to remove the RSH from the sour gas stream 2 , 3 and to catalyze the reaction of the H 2 S with SO 2 , if present, to produce elemental sulfur which can eventually be recovered by regenerating the guard bed 6 , 6 a at a temperature of 220° C. in a flow of a N 2 sweep gas 4 . Moreover, the alumina guard bed 6 , 6 a will catalyze the hydrolysis of the COS and/or CS 2 to H 2 S and CO 2 prior to the respective primary (or secondary) amine-based absorber 7 , 7 a.
In a commercial application, a single stream containing acid gases will normally be treated. But in the laboratory demonstration unit of FIG. 1 , for ease of operation, two streams, 2 and 3 comprise the feed gas stream. Stream 2 is a mixture of nitrogen and hydrogen sulfide and stream 3 is a mixture of the other components: CO 2 , H 2 , CO, CH 4 and N 2 . Streams 2 and 3 are mixed to produce a synthetic sour gas mixture containing CO 2 , H 2 S, H 2 , CO, CH 4 and N 2 . The flow rates of the inlet gas streams 2 and 3 are controlled via mass flow controllers and the pressure of the guard bed 6 , 6 a and absorber column 7 , 7 a is regulated by a back pressure control valve 10 . The pressure of the inlet feed stream 2 , 3 is about 130 psig and temperature is about 20° C. The synthetic sour gas stream 2 , 3 is initially passed through valve 5 to a guard bed 6 comprising alumina and/or activated carbon at 120° C. Under these conditions, the COS and/or CS 2 is hydrolyzed to H 2 S and CO 2 , while SO 2 , if present, is converted to elemental sulfur by the reaction with the H 2 S present in the feed gas stream. Subsequently, the effluent gas from the protective guard bed 6 is cooled down and then fed to a primary absorber column 7 containing an amine-based absorbent 32 to selectively remove the H 2 S and/or CO 2 from the sour gas stream. The H 2 S and CO 2 are absorbed immediately, and a purified produced gas containing H 2 , CO, CH 4 and N 2 leaves the absorption bed 7 through valve 8 . During the absorption mode, valves 8 and 9 are employed to direct the de-sulfurized gas from the absorber column 7 to a micro gas chromatograph 11 equipped with an automated stream selection means (not shown) to determine the moment of breakthrough of the acidic gas, and when detected, to adjust valve 8 to direct flow from absorber column to pump 12 during the desorption phase (see below).
The acidic gas absorption mode is performed at room temperature and a pressure of 100 psig, while the desorption mode is conducted at a temperature of 130° C. using a sweep gas such as N 2 or CO 2 .
Upon the acidic gas breakthrough (ie upon saturation of the amine-based absorbent 32 in primary absorbent column 7 and when detected by gas chromatograph 11 or other similar device-), the sour feed gas stream 2 , 3 is switched via valve 35 to secondary guard bed/absorber column system B, and valve 8 redirects the produced gas stream from secondary system B to gas analyzer 11 . Secondary system B has a secondary protective guard bed 6 a , and secondary amine absorber column 7 a . At such time the primary absorber column 7 is converted to a desorption mode. Specifically, the loaded or rich absorbent 32 , i.e. absorbent containing the absorbed H 2 S and CO 2 within amine absorber column 7 is heated to 130° C. to free the H 2 S and CO 2 from the absorbent. Therefore, the pressure of the absorber column 7 increases from 100 psig (at room temperature) to 150 psig. At this point, the rich gas stream leaving the absorber 7 is composed of H 2 S, CO 2 and N 2 (sweep gas). If CO 2 is used as a sweep gas, the resultant gas stream cannot be processed in Claus plant because the ratio of the H 2 S to CO 2 would be too low. Conversely, this stream is suitable for the H 2 S direct oxidation to elemental sulfur process. The process according to this invention, therefore, provides a subsequent batch process for the partial oxidation of the H 2 S present in this stream to elemental sulfur. The sulfur removal efficiency of the batch process according to this invention is greater than 99% by volume.
In the second step of the process, and with continued reference to FIG. 1 , the H 2 S-rich gas from the absorber column 7 is sent to an H 2 S direct oxidation system 30 to partially oxidize the H 2 S to elemental sulfur. Accordingly, the CO 2 /H 2 S desorbed gas stream at a pressure of 150 psig is passed through valve 8 and then mixed with a molecular oxygen containing stream 1 to produce a gas mixture containing mainly CO 2 , H 2 S, O 2 and/or N 2 . Typically, small amounts of COS and SO 2 byproducts are produced during the H 2 S direct oxidation reaction. Therefore, the flow rate of the molecular oxygen-containing stream is adjusted such that the molecular oxygen to H 2 S ratio is less than 0.5. The resultant gas mixture at a pressure of about 150 psig is then sent to a gas circulating pump 12 to supply the gas mixture to the H 2 S direct oxidation system 30 having a H 2 S oxidation reactor 16 . The feed gas flow rate for the H 2 S direct oxidation reactor 16 is controlled via a mass flow controller 13 , and its pressure is monitored by a pressure gauge 14 . The feed gas stream of the H 2 S oxidation reactor 16 which forms part of H 2 S direct oxidation system 30 is firstly passed through a pre-heating coil 15 to bring the feed gas mixture to the desired temperature. H 2 S oxidation reactor 16 in the form of a down flow reactor is utilized for the oxidation of H 2 S to elemental sulfur. The down flow reactor 16 is packed with an oxidation catalyst, and located in an oven 17 and operated at a temperature slightly greater than the sulfur dew point at the oxidation reaction pressure. Initially, the pressure of the H 2 S direct oxidation reactor 16 is adjusted to 60 psig via the back pressure control valve 10 and then increased to a pressure of 100 psig upon mixing with the gas mixture during the oxidation process. As a result, the overall pressure of the H 2 S direct oxidation system 30 is about a 100 psig.
The product effluent 25 from the H 2 S direct oxidation reactor 16 comprises un-reacted H 2 S, H 2 , CO, CO2, CH 4 , N 2 , sulfur vapor and a very small amount of COS and/or SO 2 . Consequently, the produced fluid from the oxidation reactor 16 is cooled to separate the produced sulfur from the gas phase in sequential initial and secondary separators 18 , 19 respectively, and the effluent gas from the secondary sulfur separator 19 is then recycled back to the H 2 S direct oxidation system 30 to increase the overall sulfur recovery factor. The product gas from secondary separator 19 is passed through valve 9 , micro filter 20 , valve 5 and then to the guard bed 6 . The temperature of the protective guard bed 6 , 6 a and amine-based absorber 7 , 7 a are maintained fairly constant during the effluent gas recycling process at temperatures of 120° C. and 130° C., respectively. As indicated earlier, the produced COS is hydrolyzed in the guard bed 6 , 6 a to H 2 S, and the produced SO 2 is removed by the reaction with the H 2 S present in the stream producing elemental sulfur. The effluent gas recycling procedure according to the second step of this process is repeated until the H 2 S in the recycle gas is less than 50 ppmv and the overall H 2 S conversion to elemental sulfur is greater than 99%.
According to the third step of the process, the primary absorber column 7 at a temperature of 130° C. and a pressure of 100 psig is purged with a gas free of CO 2 and H 2 S to avoid the re-adsorption of CO 2 and H 2 S upon cooling down the absorber to room temperature. A N 2 gas stream or a fraction of the off-gas stream from the secondary guard bed 6 a and absorber column 7 a (CO 2 and H 2 S free gas) is employed until no CO 2 is detected in the outlet gas stream. Subsequently, the primary absorber column 7 is cooled to room temperature, and valve 35 is then adjusted to prevent incoming stream flow to secondary system B, and simultaneously allowing incoming stream to flow to then be re-directed back to guard bed 6 and absorber column 7 then being used in a new CO 2 /H 2 S absorption cycle, with absorber column 7 a in secondary amine absorber system B then undergoing the desorption process earlier conducted on absorbent column 7 . When using CO 2 as the sweep gas and pure O 2 as the oxygen source, the off gas will be 99.9% pure. Meanwhile, the pressure of the oxidation reactor 16 , if not being supplied with desorbed gas from secondary system B, is reduced to 60 psig.
In one particular first preferred embodiment and with continued reference to FIG. 1 , the acidic gas containing stream at a pressure up to 1500 psig is passed through a humidifier (not shown) at a temperature in the range from 30° C. to 90° C. and then through a protective guard bed 6 comprising an RSH absorbent and/or a catalyst 32 at a temperature in the range from 30° C. to a temperature slightly greater than the sulfur dew point at the process pressure. The RSH absorbent 32 includes but is not limited to activated carbon and silica gel impregnated with Cu(II) and Mn(IV). The catalyst component thereof comprises but is not limited to alumina, titania and supported metal oxide catalyst. The use of the guard bed 6 , 6 a is advantageous in the case of feed gas streams comprising CO, CO2, RSH, COS and SO 2 . The metal oxide/s catalyst included in the guard bed 6 , 6 a hydrolyzes the COS and CS 2 to H 2 S and CO 2 and reduces the SO 2 , if present in the feed stream or produced as a byproduct during the H 2 S direct oxidation, to elemental sulfur. Therefore, H 2 S is the only sulfur constituent in the off-gas stream from the guard bed 6 , 6 a . The off-gas stream from the guard bed 6 , 6 a is then passed through valve 8 and directed to initial and secondary separators 18 , 19 and therein cooled down. The H 2 S and CO 2 are simultaneously removed from the off-gas stream by a primary acidic gas removal unit 7 , 7 a . The acidic gas removal units 7 , 7 a may contain any of the available technologies based on the liquid or solid absorbents which are selective toward both H 2 S and CO 2 gases. Once the acidic gases have broken through in either acidic gas removal unit 7 , as detected by the gas analyzer 11 , the feed gas stream is switched to a secondary guard bed/acidic gas removal unit B, and the primary acidic removal unit 7 is conducted to a desorption process at a temperature higher than the absorption temperature. Carbon monoxide, if present in the feed gas, tends to react with the H 2 S to form COS (equation 6) in the amine based acidic gas removal units. Typically, the COS produced in the acid removal units 7 , 7 a reacts with the amine based sorbents and a higher energy is required to regenerate the amine based sorbents. Moreover, a considerable amount of COS will be produced during the oxidation of H2S to elemental sulfur which in turn will reduce the sulfur selectivity per each cycle. Although the produced COS will be hydrolyzed to H 2 S in the guard bed, the overall sulfur removal process will be too long (Example 2). Therefore, once the acidic gases have broken through, the off-gas stream from the primary acidic gas removal unit 7 is mixed with a molecular oxygen containing stream 1 and the resultant mixture is then sent to an H 2 S direct oxidation reactor 16 comprising a suitable oxidation catalyst at a temperature slightly greater than the sulfur dew point at the reaction pressure. The present invention employs any catalyst suitable for the oxidation of H 2 S to elemental sulfur. Typically, the oxidation catalyst comprises an oxide and/or sulfide form of one or more metals deposited or mixed with one or more refractory metal oxides. The metal oxides and/or sulfides include, but are not limited to oxides and/or sulfides of V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Pd, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Bi or any combinations thereof. The refractory metal oxides include, but are not limited to Al, Ti, Si, Zr and any combinations thereof.
According to one embodiment of the present invention, the high desulfurization level of the resultant mixture is achieved by utilizing a batch process, which is accomplished by recycling the effluent gas from the H 2 S direct oxidation unit 16 to the primary guard bed 6 at a temperature in the range of from 30° C. to a temperature slightly greater than the sulfur dew point, carrying out acidic gas removal at a temperature greater than the acidic gas absorption temperature and then directing such stream flow to the H 2 S direct oxidation unit 16 . Interstage cooling between recycling is accomplished via initial and secondary separators 18 , 19 which are provided to remove the produced sulfur from the recycle stream. The effluent gas recycling process is repeated until the H 2 S concentration in the recycle gas is about 10 ppmv. Before cooling down to room temperature, the primary acidic gas removal unit 7 is purged with an H 2 S and CO 2 free gas such as N 2 (stream 4 , by adjusting valve 35 to permit flow thereof) and the off gas stream from the purging process is mixed with the feed gas stream of the secondary guard bed/acidic gas removal unit B. Meanwhile, the pressure of the direct oxidation reactor 16 is reduced to 60 prig, producing a CO 2 stream of purity greater than 99.9% by volume.
In a second embodiment, the acidic gas removal unit 7 , 7 a according to the present process comprises amine based sorbents suitable for the removal of the acidic gases from acidic gases containing streams and for the hydrolysis of COS to H 2 S and CO 2 at low temperatures. These amines include but are not limited to 1,4-Diazabicyclo[2,2,2]-Octane, 1,5-Diazabicyclo[5,4,0]-Undec-5-ene, 1,4-dimethylpiperazin-2-one and 1,5-Diazabicyclo[4,3,0]-non-5-ene. These amines can be in the liquid form or supported on any type of the porous solid support systems known in the art. The use of these amines is advantageous in the case of using feed streams of high CO content because it eliminates the necessity of the purging step required for the removal the CO from the acidic gas removal units.
In a third embodiment, one or both of the acidic gas removal units 7 , 7 a according to the present process comprise amine based sorbents of high selectivity toward H 2 S. The amines suitable for manufacturing the sorbents according to the present process include but are not limited to one or more of N-methylpyrrolidone (NMP)/dodecane, 1,4-Diazabicyclo[2,2,2]-Octane and diisopropanolamine. These amines can be in the liquid form or supported on any type of the porous solid support systems known in the art. The benefits of utilizing the high H 2 S selective amine sorbents is that it can handle a large volume of the acidic gas containing streams and increase the concentration of the H 2 S in the off-gas stream from the acidic gas removal unit 7 , 7 a.
In a fourth embodiment according to the present invention, an H 2 S and/or CO 2 containing stream is supplied to a primary acidic gas removal unit 7 without pretreatment. The acidic gas removal unit comprises amine based sorbents suitable for the COS hydrolysis to H 2 S and of high H 2 S absorption selectivity. Once the acidic gases have broken through, the primary acidic gas removal unit 7 is purged at room temperature with N 2 gas to remove the residual CO gas, if present in the feed gas stream, and is then conducted to a desorption mode at a temperature higher than the absorption temperature. The effluent stream from the primary acidic gas removal unit 7 is mixed with a continuous flow of a molecular oxygen containing stream 1 and the oxygen to H 2 S ratio in the resultant gas mixture is deliberately adjusted to a ratio less than 0.5 to avoid the oxidation of the H 2 S to SO 2 . The resultant gas mixture is then supplied to an H 2 S direct oxidation system 30 having an H 2 S direct oxidation reactor 16 containing any H 2 S oxidation catalyst known in the art to partially oxidize the H 2 S in the gas mixture to elemental sulfur. Similarly, the high desulfurization level of the gas mixture can be achieved in a batch process by recycling the off-gas stream from the H 2 S direct oxidation reactor 16 to the acidic gas removal unit 7 , 7 a at a temperature greater than the acidic gas absorption temperature.
Example 1
This example illustrates the first embodiment. In this example, the acidic gas removal unit 7 comprises a porous solid-supported amine sorbent to remove the acidic gases from the feed stream. The supported amine sorbent utilized in this example has a high absorption capacity for H 2 S ad CO 2 .
Synthesis of the Sorbent
The supported amine sorbent was synthesized similarly to reported procedure (see, U.S. patent Ser. No. 13/399,911 filed Feb. 17, 2012). The absorbent was manufactured in small fractions which were combined. The surface physical characteristics of the support utilized are shown in Table 1.
TABLE 1
Physical characteristics of the absorber supports
Absorber support
Examples 1 and 2
Example 3 and 4
Support Code
Degussa 4041
Alcoa LD-5
Surface Area, m 2 /g
155
300 min
Pore Volume, cc/g
0.9-1.0
0.63
Bulk Density, g/cc
0.4400-0.460
0.465
A1 2 0 3 , % wt
<500 ppm
99
S102, % wt
>99.8
0.40 max
Fe203, % wt, max
<30 ppm
0.04
Approximately 500 ml of the synthesized sorbent particles were enclosed between two glass wool zones and loaded into a down flow stainless steel absorber column. The absorber column was pretreated with a N 2 gas stream at a temperature of 130° C. for 2 hours. The acidic gas absorption mode was conducted at room temperature and a pressure of 100 psig. Two different gas streams were used to prepare a synthetic feed gas of a composition shown in Table 2, which is similar to the composition of the gas produced from the THAI™ process.
TABLE 2
Synthetic feed gas composition.
Component
% by volume
H 2
1.83
O 2
00
N 2
75.41
CH 4
5.49
CO
1.04
CO 2
15.73
H 2 S
0.50
The stream 2 , 3 containing acidic gases was passed through the absorber column 7 with a flow of 330 ml/min and the breakthrough time of the acidic gases was determined by a micro gas chromatograph 11 equipped with an automated stream selection valve. Once the acidic gases broke though, the feed gas stream 2 , 3 was switched to a secondary absorber column system B and the primary absorber column 7 was purged with a N 2 gas stream 4 to remove the residual CO. Subsequently, the temperature of the absorber column 7 was increased gradually to 130° C. to free the adsorbed H 2 S and CO 2 , and the pressure of the absorber column 7 increased from 100 psig to about 150 psig. The temperature of the absorber column 7 was kept fairly constant at a temperature of 130° C. to avoid the re-adsorption of the H 2 S and CO 2 during the circulation of the off-gas stream from the absorber column 7 . The off-gas stream from the absorber column 7 was mixed with a continuous flow of air and the resultant gas mixture was then fed to an H 2 S direct oxidation reactor 16 via a gas circulating pump 12 . The air flow was adjusted such that the ratio of oxygen to H 2 S was less than 0.5.
FIG. 2 (Line 1 ) shows the variation in the H 2 S concentration in the recycle gas stream from the absorber column 7 during the gas circulation step. At this point, the recycle gas stream from the absorber column 7 became the feed gas stream of the H 2 S direct oxidation reactor 16 .
The H 2 S oxidation reactor 16 was loaded with 20 ml of an alumina-supported bismuth/copper oxidation catalyst and the H 2 S oxidation reaction was conducted at a temperature of 220° C. and a pressure of 100 psig. The flow rate of the feed gas stream of the oxidation reactor 16 was adjusted via a mass flow controller 13 mounted on the recycle gas stream from the circulating pump 12 to supply the feed gas stream to the H 2 S direct oxidation reactor 16 at a gas hourly space velocity of 1000 hr −1 . The produced fluid from the H 2 S oxidation reactor 16 entered a sulfur knockout separator 18 to remove the sulfur from the product gas stream. A 2μ stainless steel filter was also employed to capture the trace of the sulfur.
FIGS. 3 , 4 and 5 (Line 1 ) illustrate the variation in the H 2 S, COS and SO 2 respectively in the product gas from the H 2 S direct oxidation reactor 16 during the circulation step. From FIGS. 4 and 5 (Line 1 ) small amounts of SO 2 and COS were produced as byproducts from the H 2 S oxidation reactor 16 . The produced gas from the sulfur knockout separator 18 was passed through a humidifier comprising water at a temperature of 80° to increase the water partial vapor pressure as required for the hydrolysis of the COS present in the product gas. The humidified product gas was then recycled to the protective guard bed 6 .
The productive guard bed 6 was loaded with 10 ml of pure alumina catalyst and operated at the same system pressure (about 100 psig) and at a temperature of 120° C. The outlet stream from the protective guard bed 6 was cooled down and then fed to the absorber column 7 . The small amount of the COS produced during the H 2 S oxidation was hydrolyzed to H 2 S, while SO 2 was reduced to elemental sulfur in the guard bed 6 . Therefore, no COS or SO 2 was detected and H 2 S was the only sulfur compound in the off-gas stream from the guard bed 6 . The off-gas steam from the protective guard bed 6 was then recycled to the absorber column 7 . The gas circulation process was repeated until the H 2 S in the recycle gas was 10 ppm. Subsequently, the absorber column 7 at a temperature of 130° C., was purged with a N 2 gas stream 4 to avoid the re-adsorption of CO 2 .
Example 2
As a further illustration of the First Embodiment, this Example is identical to Example 1 except the absorber column 7 was not purged to remove the residual CO after the acidic gas absorption step. FIGS. 2 and 3 (Line 2 ) respectively show the variation in the H 2 S concentration in the recycle gas stream from the absorber column 7 and from the oxidation reactor 16 during the gas circulation step. As a consequence of the presence of CO, a considerable amount of COS was produced during the H 2 S direct oxidation reaction, FIG. 4 (Line 2 ). In addition, a sudden increase in the SO 2 concentration was detected in the outlet gas stream of the H 2 S direct oxidation reactor toward the completion of the oxidation cycle, FIG. 5 (Line 2 ). This can be attributed to the sudden increase in the oxygen-to-H 2 S ratio toward the completion of the oxidation cycle. Nevertheless, no COS or SO 2 was detected in the recycle gas from the guard bed and the overall desulfurization process duration increased significantly due to the low sulfur selectivity during the H 2 S direct oxidation reaction to elemental sulfur.
Example 3
This is an illustration of the Second and Third Embodiments. This example is identical to Example 2 except that the acidic gas removal unit contained an amine based sorbent of high H 2 S selectivity and is suitable for COS hydrolysis to H 2 S and CO 2 .
Synthesis of the Sorbent
The synthesis of the absorber was conducted by ordinary methods as practiced by those knowledgeable in the art. The amine based absorber support was Alumina spheres (LD-5) obtained from Alcoa. The physical characteristics of the support are shown in Table 1. Approximately, 25.5 g of 1,4-Diazabicyclo[2,2,2]-Octane was dissolved in acetone and the solution was added to 427.2 gm of the alumina support by the method of incipient wetness to achieve 5.6 wt. % amine in the final sorbent. The absorbent was left in the air to dry over night. Subsequently, the absorbent was loaded in the absorber column 7 and then conditioned at a temperature of 105° in a flow of nitrogen for 3 hours. The acidic gas absorption mode was conducted at room temperature and a pressure of 100 psig utilizing a gas stream of a composition similar to the gas stream employed in Examples 1 and 2. After the H 2 S has broken through, the absorber column 7 was conducted to a desorption mode at a temperature of 120° C.
The breakthrough time of the H 2 S from the acidic gas removal unit 7 increased significantly upon using the hindered amine based sorbent and therefore, the desulfurization step of the desorbed gas from the acidic gas removing unit 7 was expected to be longer than the acidic gas removal step. However, for a continuous sulfur removal process, the desulfurization step of the desorbed gas from the primary absorber column 7 was operated at low overall desulfurization efficiency and was deliberately terminated when the H 2 S in the recycle gas stream from the primary absorber column 7 was about 1750 ppm FIG. 2 (Line 3 ). Subsequently, the primary absorber column 7 was cooled down and therefore, the overall pressure of the system decreased 60 psig. The inlet feed stream of the H 2 S direct oxidation reactor 16 was then switched to the outlet gas stream from the secondary absorber column 7 a . Meanwhile the primary absorber column 7 was cooled down further to room temperature and then conducted to a new acidic gas removal cycle. Similarly, no COS or SO 2 was detected in the recycle gas stream from the protective guard bed 6 .
Example 4
This is an Illustration of the Fourth Embodiment
This example is identical to Example 3, except that the protective guard bed 6 (and 6 a ) was eliminated from the process. The oxygen to H 2 S ratio in the feed gas stream of the H 2 S oxidation reactor was adjusted to a ratio less than 0.5 to prevent the oxidation of H 2 S to SO 2 . Therefore, no SO 2 was detected in the outlet gas stream during the desulfurization step. However, a considerable amount of the COS was detected in the recycle gas stream from the H 2 S direct oxidation reactor 16 FIG. 4 (line 4 ). The recycle gas stream from the oxidation reactor 16 was cooled down to a temperature of 50° C. to condense the produced sulfur and the moistened off-gas stream from the sulfur secondary separator was then recycled to the primary absorber column 7 to hydrolyze the produced COS to H 2 S and CO 2 . Typically, the oxidation of H 2 S to elemental sulfur produces water (reaction 3), therefore, no additional water was required for the hydrolysis of the produced COS to H 2 S in the primary absorber column 7 . | A method of reducing sulfur compounds from an incoming gas stream, comprising flowing the gas stream over a hydrolysis catalyst to convert COS and CS 2 to H 2 S and reduce SO 2 to elemental sulfur to form an effluent stream; providing an acidic gas removal unit comprising an absorbent; flowing said effluent stream over said absorbent to produce a stream free of acidic gases; applying an acidic-gas desorption mode to said acidic-gas rich absorbent to produce an acidic gas stream; introducing oxygen to said acidic gas-rich stream; providing a direct oxidation vessel containing catalyst suitable for catalyzing the oxidation of the H 2 S to sulfur wherein the temperature of the vessel is at or above the sulfur dew point at the reaction pressure; and flowing said acidic gas-rich stream over said catalyst to produce a processed stream having a reduced level of sulfur compounds. | 8 |
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
This application is the National Phase Application under 35 USC §371 of International Application No. PCT/EP2010/055634, filed Apr. 27, 2010, which claims priority to German Patent Application 10 2009 0002 702.5, filed Apr. 28, 2009.
BACKGROUND
A. Technical Field
The present invention relates to a micromechanical sensor comprising a substrate and at least one mass which is situated on the substrate and which moves relative to the substrate for detecting motions of the sensor due to an acceleration force and/or Coriolis force which occur(s), the mass and the substrate and/or two masses which move toward one another being connected by at least one bending spring device, and the bending spring device having a spring bar and a meander, provided thereon, having a circle of curvature whose midpoint is inside the meander.
B. Background of the Invention
Micromechanical sensors are used for detecting accelerations and/or yaw rates along a spatial axis or at least one of three mutually orthogonal spatial axes. The operating principle is basically that a sensor mass is moved relative to a substrate as a response to the corresponding acceleration or yaw rate of the sensor. For this purpose, the sensor mass is movably mounted on the substrate by means of a bending spring device, which is generally composed of one or more bending springs. The design of these bending springs primarily determines the particular directions in which the sensor mass is movable. The spring stiffnesses of the bending springs are different in the individual spatial directions in order to more or less permit different bending directions. This difference in movability may be influenced by varying the cross-sectional surface area of the bending spring, and also by virtue of the spatial course of the bending spring. In particular for a meandering design of the bending spring, relatively high elasticity may be achieved in the plane of the meander. However, shock effects due to impacts to the sensor may cause extreme bending stresses which may result in damage to the bending spring device.
An acceleration sensor is known from U.S. Pat. No. 6,401,536 B1, in which a sensor mass is attached to an anchoring of a substrate by means of a bending spring device. The bending spring device is composed of multiple individual bending springs, which in each case are attached at one end to the anchoring. In addition, at its end facing the sensor mass the bending spring is divided into two branches, each of which is situated on the sensor mass. Each of the branches of the bending spring is curved in a meandering shape, the individual sections extending in parallel to one another. Each turn of the meander is inflected by 180° in a semicircular manner. Depending on the design described, one or more meanders per branch is/are provided. Each of the turns of the meander is such that the midpoint of the particular circle of curvature to which the bending spring conforms is inside the particular meander.
A micromechanical gyroscope is known from DE 698 22 756 T2, in which a sensor mass is likewise attached to an anchoring of a substrate by means of a bending spring device. The bending spring device, the same as in the previously cited document, permits elastic movability of the sensor mass about the anchoring. The bending spring device is composed of three individual bending springs, each of which is curved in a meandering shape. The individual sections of the meander are not oriented parallel to one another. The bending radius of the particular bending spring extends over less than 180° in the corresponding section, so that the arms are spread apart. Once again, the midpoint of the particular bending radius is inside the meander.
One disadvantage of the prior art is that relatively high peak stresses occur in the bending spring devices during extreme deflections of the sensor mass. This may result in damage to the springs, and thus, to the entire sensor. In particular, the springs may break or become torn, thus hindering or completely preventing the movability of the sensor mass.
The object of the present invention, therefore, is to provide a micromechanical sensor which has a movable sensor mass for which on the one hand its movability is controllable, and for which on the other hand even high bending loads may be absorbed at its springs without the expectation of damage.
The object is achieved by a micromechanical sensor having the features of claim 1 .
A micromechanical sensor according to the invention has a substrate and at least one mass which is situated on the substrate and which moves relative to the substrate for detecting linear and/or angular accelerations of the sensor. On the one hand, the mass moves in the sense of a drive motion form, which in the absence of external accelerations is stationary, and on the other hand responds with detection motions when acceleration forces and/or Coriolis forces act on the sensor. The moving sensor mass is attached to the substrate by means of at least one bending spring device. Alternatively, multiple masses which move toward one another may be connected by at least one bending spring and moved relative to one another. Consequently, it is not necessary in each case for the sensor mass to be situated directly on the substrate. In some embodiments of micromechanical sensors according to the invention, the sensor mass may also be attached to a drive mass, for example, and together with the drive mass moved as a primary motion, and moved relative to the drive mass only for indicating an acceleration force and/or Coriolis force. The sensor mass and the drive mass are then connected to one another via the corresponding bending spring device. The bending spring device has a spring bar and a meander provided thereon.
The meander has a radius of curvature having a midpoint inside the meander. A particular elasticity of the bending spring device is achieved as a result of the meandering design of the bending spring device. According to the invention, the bending spring device is designed in such a way that, in addition to the radius of curvature having the inner midpoint, the meander has at least one further radius of curvature having a midpoint outside the meander. The at least one further radius of curvature is situated between the meander and the spring bar. Stresses which occur on the bending spring device are thus reduced. Damage or even breakage of the bending spring device during extreme deflections of the sensor mass are thus avoided. In addition, uniform deflection of the sensor mass is assisted, so that besides the reduction in the risk of damage, the accuracy of the micromechanical sensor in detecting accelerations or rotational motions of the sensor is improved.
In one advantageous embodiment of the invention, the bending spring device has multiple spring bars. When the meander is situated on the spring bar, stresses which occur on the bending spring device may be greatly reduced due to bending which is present. The risk of breakage of or damage to the spring bar is thus reduced.
If the meander is designed in such a way that it merges into the spring bar in a rounded manner, stresses which are caused by bending may be achieved which are more uniform and which do not have unacceptable peaks, even in extreme bending situations. Adjacent components of the meander may in particular be a first and a second spring bar, the sensor mass, the substrate itself, or an anchoring for attachment to the substrate.
Similarly as for the meander merging into the adjacent component in a rounded manner in order to avoid stress peaks, it is advantageous when the spring bar(s) likewise merge(s) in a rounded manner into the adjacent component, in particular the sensor mass or an anchoring for attachment to the substrate. Stress peaks are thus reduced not only in the region of the meander, but also in the remainder of the bending spring device.
In one advantageous embodiment of the invention, another measure for reducing the load on the bending spring device may be achieved by the rounded transition having a non-constant radius of curvature. The meanders as well as the spring bars are thus connected to the adjacent components in a particularly gentle manner with regard to their stresses. The uniformity of the bending and the associated accuracy of the measurement by the sensor are thus improved.
It is particularly advantageous when the rounded transition is elliptical. This also has a positive effect regarding damage and the measuring accuracy of the sensor.
In one particularly advantageous embodiment of the invention, it is provided that the meander and/or the spring bar merge(s) in a branched manner into the sensor mass, the substrate, and/or an anchoring for attachment to the substrate. Stress peaks in the transition points are thus additionally reduced.
When the meander and/or the spring bar has/have a convex curvature, this results in a bending characteristic which reduces stress peaks even in extreme situations, such as mechanical shock events, for example. Damage to the sensor is thus largely avoided.
In one particularly advantageous embodiment of the invention, the bending spring device has multiple meanders which extend in a point symmetrical or axially symmetrical manner with respect to one another. This is advantageous in particular for high bending rates or large expected stresses, since the overall stress may be distributed over the multiple meanders.
A particularly weak inner curvature is achieved when the inflection region of the meander conforms to the inner circle of curvature by greater than 180°. As a result of the large radius of curvature of the inner circle of curvature which is thus made possible, this advantageously causes peak stresses to be distributed over a larger area, thus allowing them to be kept low.
When embodiments of the invention having multiple inner circles of curvature are provided, it is particularly advantageous when the meander conforms overall to the circles of curvature by greater than 180°. In addition, similarly as for a particularly large contact of a single inner circle of curvature, stress peaks are kept low. The individual circles of curvature are connected to linear or also curved sections of the spring.
To obtain a large contact of the circle(s) of curvature, it is advantageous when the circle of curvature of the outer midpoint, or, for multiple outer circles of curvature, the circles of curvature of the outer midpoints, conform(s) overall to the meander by greater than 90°. A concave or convex curvature of the meander is thus achieved.
SUMMARY OF THE INVENTION
Brief Description of the Drawings
Further advantages of the invention are described in the following exemplary embodiments.
FIG. 1 shows a top view of a gyroscope,
FIG. 2 shows a detail from FIG. 1 ,
FIG. 3 a shows a schematic illustration of the design of a bending spring according to the prior art,
FIG. 3 b shows a schematic illustration of the design of a bending spring according to the invention, and
FIG. 4-10 show examples of bending spring devices according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a top view of a sensor 1 according to the invention, in the present case, a yaw rate sensor for detecting rotations of the sensor 1 about an axis. An anchoring 3 is situated on a substrate 2 of the sensor 1 , and a sensor mass 5 is rotatably fastened to the anchoring by means of four springs 4 . The sensor mass 5 is connected to the drive mass 7 by means of a bending spring device 6 . Four of the bending spring devices 6 are uniformly distributed at the periphery of the sensor mass 5 . The drive mass 7 , by means of electrodes 8 attached thereto, is to be set in a primary motion in which it vibrates in an oscillating manner about the z axis which projects out of the plane of the drawing. This primary motion is completed almost exclusively by the drive mass 7 , and does not continue on the sensor mass 5 . Thus, the sensor mass 5 does not take part in the primary motion of the drive mass 7 . If the substrate 2 , i.e., the sensor 1 , then rotates about an x or y axis situated in the plane of the drawing, Coriolis forces result which attempt to tilt the drive mass 7 about the y or x axis. As the result of an appropriate controlled stiffness of the springs 4 and bending spring devices 6 , the drive mass 7 together with the sensor mass 5 allows this motion. For this purpose, the bending spring devices 6 are designed in such a way that on the one hand they allow decoupling of the oscillation of the drive mass 7 from the sensor mass 5 in the primary oscillation, i.e., have a relatively soft design in the circumferential direction with regard to the reaction motion, namely, the secondary oscillation about the y or x axis, and on the other hand they have a relatively stiff design, so that the deflecting drive mass 7 allows the sensor mass 5 to take part in this motion.
Due to the necessary bending of the bending spring device 6 in the circumferential direction, and on the other hand because of the stiffness with regard to an oscillation about the y or x axis, very different requirements are imposed on the bending spring devices 6 which sometimes result in high bending stresses. The design according to the invention of the sensor has bending spring devices 6 which, due to a targeted design, prevent these excessive bending stresses on the bending spring device 6 .
FIG. 2 shows the bending spring device 6 in an enlarged illustration. The bending spring device 6 is composed of a spring bar 9 and two meanders 10 situated thereon. The meanders 10 are located on a type of fork or branch of the spring bar 9 . The meanders extend essentially at right angles to the length of the spring bar 9 , on both sides of the spring bar 9 .
At its first end having a rounded transition 11 , the spring bar 9 is situated on the sensor mass 5 . The other end of the spring bar 9 , likewise having a rounded transition 11 , is situated on the drive mass 7 . To avoid an unfavorable mass accumulation and to improve the strength at the connecting points, in the region of the transitions 11 a recess 12 is provided in each case which forms a branch of the spring bar 9 . The transitions may, for example, be circular or also elliptical.
The meander 10 is rounded, and has radii of curvature which on the one hand have an inner midpoint and on the other hand have outer midpoints. Starting at the spring bar 9 , the meander 10 is composed of a first rounded subregion whose center of curvature is outside the meander 10 . This first curvature results in a concave curvature of the meander 10 . This first section is adjoined by a curve having a radius of curvature whose midpoint is inside the meander 10 . This second curvature extends around an inflection point of the meander. In the present exemplary embodiment, this second curved section conforms to its circle of curvature by greater than 180° in order to compensate for the first inwardly directed concave curvature. This is followed by a third section which once again has a concave curvature of the meander 10 . The midpoint of the present circle of curvature is once again outside the meander 10 . The meander 10 then bends back into the spring bar 9 . This curvature with the spring bar is also gradual, and has a rounded transition. The two meanders 10 are mirror images of one another. However, depending on the requirements for the bending spring device 6 , the meanders may also be asymmetrical; i.e., only one meander 10 might be present, or the two meanders 10 could have different designs. This design principle avoids a situation in which a region having a high degree of curvature, i.e., a small radius of curvature, is formed at the outer end of the meander, at its inflection region. In regions of high curvature, during load on the bending spring device 6 high stress peaks usually form which may adversely exceed the breaking point of the material.
FIGS. 3 a , 3 b illustrate the design principle of the bending spring device 6 according to the invention. FIG. 3 a shows a meander 10 as it would appear without the modified geometry within the meaning of the present invention. The turn of the meander conforms to a circle of curvature K having a radius r and midpoint MP. Due to the small distance between the spring bars, the radius of curvature r is small, and the curvature is correspondingly high. If this structure is subjected to load by forces situated within the plane of the drawing, a deformed state results which likewise is within the plane of the drawing. The peak stresses which occur are always located in the region of the smallest radii of curvature, thus, in the present case, in the region of the circle of curvature K.
In FIG. 3 b this peak stress region has been mitigated by reducing the curvature, i.e., enlarging the radius of curvature r 1 compared to r. As a result, the inflection region of the meander now conforms to the circle of curvature K 1 by greater than 180°. To also achieve a small distance between the inner quasi-parallel meander bars, which is desirable from a design standpoint, the spring must be bent back in such a way that it conforms to circles of curvature K 2 and K 3 , whose midpoints—in contrast to the inner circle of curvature K 1 —are situated outside the meander. Here as well, it is ensured that the radii of curvature r 2 and r 3 are kept as large as possible in order to avoid regions of high curvature, and therefore high peak stresses, to the greatest extent possible.
As a result of this curved design of the meander 10 , stress peaks during a deflection of the bending spring device 6 , i.e., the meander 10 , are kept so low that in normal operation of the sensor, damage to the bending spring device 6 or meander 10 is avoided, even under extreme operating conditions such as shock situations, for example. The bending stresses are much lower than for bending spring devices of the prior art according to FIG. 3 a , which are designed without such interrelated radii of curvature.
FIGS. 4-10 illustrate various designs of meanders according to the present invention. These exemplary embodiments are not all-inclusive. A number of other bending spring devices are possible which are designed according to the inventive principle.
FIG. 4 shows a bending spring device 6 according to the invention, having a meander 10 which in its first section has two bending radii in the outer region. Starting from a linear progression of the bending spring device 6 , the meander 10 having a circle of curvature K 4 is introduced. The meander 10 extends essentially at a right angle away from the first linear progression, starting at a first component. A further, smaller circle of curvature K 5 is subsequently provided, by means of which the bending spring extends practically in the opposite direction. In the region of the inflection point of the meander 10 , on the inside of the meander 10 , a third circle of curvature K 6 is provided, to which the bending spring conforms. After a short linear section, the bending spring leads back, with the same bending radii K 6 , K 5 , and K 4 , to the last linear section and opens into the second elastically supported component. Thus, the two components situated to the left and right of the bending spring device 6 , which may be the sensor mass 5 and the drive mass 7 , or also an anchoring 3 and the sensor mass 5 or the drive mass 7 , for example, are elastically connected to one another by means of the bending spring device 6 . As a result of the corresponding radii of the circles of curvature, which are as large as possible, to which the bending spring device 6 , i.e., the bending spring, conforms, a much softer and more flexible transition of the individual sections is achieved, thus allowing stress peaks to be kept low.
FIG. 4 a shows a bending spring device 6 which is optimized compared to the design in FIG. 4 . The circles of curvature K 4 and K 5 have been combined into a single circle of curvature K 4 , 5 . The larger radius of the circle of curvature K 4 , 5 compared to the radii of the circles of curvature K 4 and K 5 results in a smaller curvature (curvature=1/radius) of the circle of curvature K 4 , 5 . The stress on the bending spring is therefore lower, and the risk of damage is thus reduced.
FIG. 5 illustrates a meander 10 according to the invention, having two outer circles of curvature and one inner circle of curvature. The return back to the second component is symmetrical, once again having two outer circles of curvature. The transition 11 into the components, each of which is to be elastically supported, is made via a type of fork of the bending spring. The transition 11 of the bending spring device 6 into the components to be connected is thus also made in a particularly suitable manner. The two outer radii of curvature are such that they have an osculating line of greater than 90° overall at the circles of curvature, so that the bending spring is deflected by greater than 90°. In contrast to the design in FIG. 4 , in the present case only a single inner circle of curvature is provided. The contact of the bending spring is greater than 180°.
FIG. 5 a shows a design which is improved over that in FIG. 5 . The two outer circles of curvature in each case have been combined into one large circle of curvature having a small curvature of the bending spring which conforms thereto. Since according to the invention a strong curvature of the bending spring is less favorable than a weak curvature, this embodiment also has advantages compared to the embodiments in FIGS. 4 and 4 a , since the inner circle of curvature is as large as possible, and the inflection is not divided into two or more smaller circles of curvature.
In FIG. 6 an outer circle of curvature K 7 and three inner circles of curvature K 8 (twice) and K 9 are provided. The bending spring of the bending spring device 6 conforms to these circles K 7 , K 8 , and K 9 , resulting in a particularly gentle transition. The sum of the contacts of the inner circles of curvature K 8 and K 9 is greater than 180°, and the contact of the respective outer circle of curvature K 7 is greater than 90°. The respective circles of curvature may be connected by means of straight or curved spring sections.
The bending spring device 6 in FIG. 7 is optimized compared to the design according to FIG. 6 . This bending spring device conforms to two outer circles of curvature K 10 and a large inner circle of curvature K 11 . The outer circles of curvature K 10 are situated inside the projection of the inner circle of curvature K 11 , resulting in a convex curvature of the bending spring. Particularly high elasticity and a low-stress design of the bending spring device 6 are achieved in this manner. The circles of curvature K 10 are smaller than the circle of curvature K 11 ; in another embodiment this may also be reversed. In the ideal case, all of the circles of curvature in question are approximately the same size, since an attempt is generally made to maximize all radii of curvature.
FIG. 8 shows a bending spring device 6 having a double meander 10 . The two meanders 10 are symmetrical to one another, and in each case approximately correspond to the meander 10 in FIG. 7 . A bending characteristic which is essentially the same in both directions of the bending spring device 6 is ensured by the symmetrical design.
In FIG. 9 , the bending spring device 6 from FIG. 8 is provided twice, one behind the other. The total of four meanders 10 form a particularly elastic bending spring device 6 which keeps stress peaks particularly low and provides a stable, durable bending spring device 6 .
FIG. 10 shows a modification of the bending spring device 6 from FIG. 9 . The spring bars 9 have a two-part design in the region of the interconnected components and between the meander pairs 10 . The elasticity and load capacity of such a bending spring device is increased even more.
The illustrated exemplary embodiments represent only a few of the designs of bending spring devices for micromechanical sensors which are possible according to the invention. Various types and sizes of circles of curvature, as well as different numbers of circles of curvature which are formed by the bending spring devices and the meanders, are possible. In addition, the term “circle” is to be construed in a very general manner. Freely configured curves are also possible. It is important that the center of curvature is on the particular described side of the bending spring. Circular arcs which merge into one another may also be used. Also important are the circles of curvature of the meander, situated inside as well as outside the meanders, which in one particularly advantageous embodiment result in convex curvatures, and thus, regions of weaker curvature and therefore reduced peak stresses. Uniform, gradually transitioning changes in the direction vector of the bending springs are achieved in this manner, thus keeping stress peaks low, in particular under extreme loads on the bending spring device, and therefore largely avoiding damage to the bending spring device.
LIST OF REFERENCE NUMERALS/CHARACTERS
1 Sensor
2 Substrate
3 Anchoring
4 Spring
5 Sensor mass
6 Bending spring device
7 Drive mass
8 Electrodes
9 Spring bar
10 Meander
11 Transition
K Circle of curvature
MP Midpoint
R Radius | A micromechanical sensor comprising a substrate ( 5 ) and at least one mass ( 6 ) which is situated on the substrate ( 5 ) and which moves relative to the substrate ( 5 ) is used to detect motions of the sensor due to an acceleration force and/or Coriolis force which occur(s). The mass ( 6 ) and the substrate ( 5 ) and/or two masses ( 5, 7 ) which move toward one another are connected by at least one bending spring device ( 6 ). The bending spring device ( 6 ) has a spring bar ( 9 ) and a meander ( 10 ), provided thereon, having a circle of curvature (K 1 ; K 6 ; K 8 ; K 9 ; K 11 ) whose midpoint (MP 1 ; MP 6 ; MP 8 ; MP 9 ; MP 11 ) and radius of curvature (r 1 ; r 6 ; r 8 ; r 9 ; r 11 ) are inside the meander ( 10 ). For reducing stresses that occur, in addition to the radius of curvature (r 1 ; r 6 ; r 8 ; r 9 ; r 11 ) having the inner midpoint (MP 1 ; MP 6 ; MP 8 ; MP 9 ; MP 11 ), the meander ( 10 ) has at least one further radius of curvature (r 2 ; r 3 ; r 4 ; r 5 ; r 7 ; r 10 ) having a midpoint (MP 2 ; MP 3 ; MP 4 ; MP 5 ; MP 7 ; MP 10 ) outside the meander ( 10 ). The at least one further radius of curvature (r 2 ; r 3 ; r 4 ; r 5 ; r 7 ; r 10 ) is situated between the meander ( 10 ) and the spring bar ( 9 ). | 6 |
PRIORITY
[0001] This application claims priority under 35 U.S.C. §119(a) of to Korean patent application filed in the Korean Intellectual Property Office on Mar. 2, 2007 and assigned Serial No. 2007-20788, the entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to frequency allocation for frequency reuse, and in particular, to an allocation apparatus and method for efficient frequency reuse in downlink in a Multi Input Multi Output (MIMO)-Orthogonal Frequency Division Multiple Access (OFDMA) broadband wireless access communication system.
[0004] 2. Description of the Related Art
[0005] With an increasing demand for frequency reuse, new methods for utilizing available frequency bands are of great importance. One of the main concerns for designing frequency channel assignment at a cell edge is the number of available receive-antennas of a receiver subjected to interference. It has been previously reported that the maximum number of streams (both desired and interfering streams) that a receiver can resolve using linear receive techniques is equal to the number of receive antennas. The number of interfering streams can be equated to the number of interfering logical streams. The interfering logical streams are defined as interfering data streams. Under this definition, receive diversity, transmit antenna selection, or transmit beamforming (TxBF) links are referred to as a single-link logical stream.
[0006] When Space Time Block Coding (STBC) is used at an interfering link, then the link experiences more than one apparent logical stream if signals are processed on a symbol-by-symbol basis. A linear Minimum Mean Square Error (MMSE) receiver based on multi-symbol processing cancels out the interferers, provided that the number of receive antennas is greater than or equal to the number of received logical streams (including desired and interfering streams). This multiple-symbol based receiver technique demonstrates robustness against any single stream interferer.
[0007] A Fractional Frequency Reuse (FFR) technology for severely Co-Channel Interference (CCI) affected Mobile Stations (MSs) at the cell edge assigns frequency channels to any particular MS based on the location of the particular MS. Usable frequency channel sets for all MSs in a cell are defined for MSs located inside the cell area (i.e., much closer compared to cell edge).
[0008] When an MS is located around a cell edge, then frequency allocation also should take care of the nearest CCI source, i.e. the nearest Base Station (BS) that is also transmitting in downlink. Therefore, based on information about the location of any MS at the cell edge, a decision regarding an available frequency set for a particular MS is made.
[0009] When interference rejection capabilities using MIMO technologies are not taken into account in an FFR design, it is clear that the benefit of MIMO communication systems will not be exploited in the frequency assignment.
[0010] The performance of the system can be greatly improved when MIMO interference cancellation capabilities are taken into account for frequency reuse assignments. Therefore, an apparatus and method for frequency allocation for FFR using the MIMO interference cancellation capabilities are needed.
SUMMARY OF THE INVENTION
[0011] An object of the present invention is to address at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an object of the present invention is to provide an apparatus and method for frequency reuse in an MIMO system.
[0012] Another object of the present invention is to provide an allocation apparatus and method for efficient frequency reuse in an MIMO downlink in an OFDMA broadband wireless access communication system.
[0013] The above aspects are achieved by providing an apparatus and method for frequency reuse in a multi input multi output system.
[0014] According to one embodiment of the present invention, a frequency reuse method for a Mobile Station (MS) using a multiple-antenna in a broadband wireless access communication system is provided. The method includes dividing a first frequency band into ‘N’ second frequency bands where ‘N’ equals a number of Base Stations (BSs); dividing each second frequency band into ‘n’ third frequency bands, wherein ‘n’ is a natural number; allocating each of the ‘N’ second frequency bands according to a number of receive antennas of the MS; and allocating each of the third frequency bands to all of the BSs, respectively.
[0015] According to another embodiment of the present invention, an apparatus for deciding a frequency reuse method for an MS using a multiple-antenna in a broadband wireless access communication system is provided. The apparatus includes a communication module for communicating with another node; a controller for transmitting a control message instructing a frequency sharing degree through the communication module, dividing, when there are ‘N’ Base Stations (BSs), a first frequency band into ‘N’ second frequency bands, dividing each second frequency band into ‘n’ third frequency bands, allocating each of the ‘N’ second frequency bands according to a number of receive antennas of the MS, and allocating each of the third frequency bands to all of the BSs, respectively; and a storage unit for storing necessary data by the controller, wherein ‘n’ is a natural number.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
[0017] FIG. 1 is a diagram illustrating network architecture according to an exemplary embodiment of the present invention;
[0018] FIG. 2 is a graph illustrating an example of frequency allocation according to an exemplary embodiment of the present invention;
[0019] FIG. 3 is a block diagram illustrating an apparatus according to an exemplary embodiment of the present invention; and
[0020] FIG. 4 is a flow diagram illustrating a frequency allocation process according to an exemplary embodiment of the present invention.
[0021] Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0023] A description of an apparatus and method for frequency reuse in an MIMO system according to the present invention is made below. The present invention proposes a novel frequency assignment technique among the cell edge MSs that exploit knowledge of the number of available receive antennas and the multiple-symbol based linear MMSE technique.
[0024] Each cell is assigned one set of frequencies for cell-edge MSs. The frequencies are shared among MSs of different interference rejection capabilities. Orthogonal frequency channels are used across the cells only for the cell-edge MSs, thus a fractional re-use factor is achieved.
[0025] The present invention is not only adapted to the number of interfering Base Stations (BSs), but to the total number of transmitted logical streams. This may be done at cell site deployment, or adaptively over time with cooperation from cell sites.
[0026] A FFR method of the present invention does not take care of the impact of the type of interferer; rather the method only concentrates on the fact that multiple CCI interferers are present for a cell edge MS.
[0027] FIG. 1 is a diagram illustrating network architecture according to an exemplary embodiment of the present invention.
[0028] In FIG. 1 , the number of receive antenna of an MS is defined as ‘Q’ and the number of downlink interferers is defined as ‘I’. As mentioned earlier, a linear MMSE receiver can cancel out at least Q-1 number of interferers. This is true even for the case when STBC is present as interferer. To satisfy this condition (i.e., achieve enough diversity required to null out the interferers) and exploit multiple-symbol processing, the present invention proposes frequency sharing between main interfering BSs 120 and 130 . The main assumptions are:
[0029] 1. There are two main interfering BSs 120 and 130 , as shown in FIG. 1 : the other interfering BSs are assumed negligible. The present invention is also intended to include more interfering BSs.
[0030] 2. A frequency band is reserved for MSs located at cell edge and shared by the interfering BSs 120 and 130 . Each BS does not know the nature of the interfering links.
[0031] 3. Spatial Multiplexing is not used for transmission to cell edge MSs. Only single logical link transmission is used.
[0032] 4. The MS knows the maximum length of STBC codes used by the interfering BSs 120 and 130 : this assumption is not strictly necessary as the MS could estimate the maximum length.
[0033] 5. STBC transmissions are synchronized for all the BSs (i.e., start at same time for all BSs).
[0034] FIG. 2 is a graph illustrating an example of frequency allocation according to an exemplary embodiment of the present invention.
[0035] In FIG. 2 , the basic principle of a frequency reuse technology of the present invention is as follows:
[0036] For Q=1, no frequency sharing is allowed, as an MS cannot nullify any interfering signal. For Q=2, frequency sharing between two BSs is allowed, because an MS can now efficiently nullify one interfering signal. For Q≧3, frequency sharing between two or more BSs is allowed.
[0037] Transmission towards one MS during downlink can cause interference for other MSs. In another words, assigning some resources to any MS located in cell edge area can also mean that some interference is generated for other MSs located at the neighboring cells. Thus, the existence of one particular MS can result in interference for other MSs. With the knowledge of the interference rejection capability, unwanted interference can be avoided for other users in the neighboring cells.
[0038] The channel assignment technology of the present invention can avoid interferences from other interfering BSs and also to ensure that one particular MS does not become source of interference for others.
[0039] Assuming that the total available frequency sets for all three BSs is denoted as ‘W’, three disjoint sets of frequencies are defined as follows:
[0040] 1. W 1 , W 2 and W 3 ⊂W
[0041] 2. W i #W j =Ø, where Ø means an empty set, for i, jε{1,2,3}.
[0042] 3. MSs located inside a cell area of all cells can use the same frequency band. The frequency band can be denoted as
[0000]
W
⋂
(
⋃
i
=
1
3
W
i
)
.
[0043] That is, when there are three BSs, three frequency sets are generated. These three frequency bands are identified by three classes, respectively. The classes are, as mentioned before, with respect to the number of available receive antennas at a corresponding MS. For the example shown in FIGS. 1 and 2 , there are three different cells and the frequencies in all of three bands mentioned above are allocated to one class.
[0044] Thus, another three sub-sets of frequencies under all the above three frequency sets are defined as follows:
[0045] 1. W i1 ∪W i2 ∪W i3 =W i
[0046] 2. W ix ∩W iy =Ø, for all i,x, yε{1,2,3}
[0047] As shown in FIG. 2 , the assignment scheme of the present invention assumes that an MS always has sufficient capabilities to nullify interfering signals. The frequency allocation principle can be described as follows:
[0048] 1. MSs with Q=1 antennas are scheduled in a frequency band W 1 where no frequency sharing between BSs is allowed.
[0049] 2. MSs with Q=2 antennas are scheduled in a frequency band W 2 where frequency sharing between two BSs is allowed.
[0050] 3. MSs with Q≧3 antennas are scheduled in a frequency band W 3 where frequency sharing between three BSs is allowed.
[0051] The sizes of these frequency sets and subsets depend on the number of available MSs located at cell edge with certain receive antenna classes. As the load factor for all these three classes is always random (or at least not deterministic), W 1 , W 2 and W 3 (and sub-channel bandwidth inside each band) must be adapted.
[0052] Frequency hopping can be used to reassign particular frequency bands and subbands. The sharing is described in FIG. 2 in frequency only, but sharing can occur over time or in a time-frequency plane or both.
[0053] The above process is generalized as follows:
[0054] If there are ‘N’ BSs, a constant frequency band (hereinafter, referred to as “First Band”) is divided into ‘N’ frequency bands. Each of the frequency bands resulting from the division of the First Band is referred to as a “Second Band,” i.e., there are ‘N’ second bands. Then, each second band is again divided into ‘n’ frequency bands. Each of the frequency bands resulting from the division by ‘n’ is referred to as a “Third Band.” Here, ‘N’ and ‘n’ are the same in size.
[0055] Then, it is set to allocate the second bands according to the number of receive antennas of an MS. That is, a first frequency band is set to be allocated to an MS having one receive antenna and in sequence, it is set to allocate an N-th frequency band to an MS having ‘N’ or more receive antennas.
[0056] Then, the third bands are allocated to all BSs (the number of BSs is ‘n’), respectively, i.e., the second band is divided into ‘n’ third bands since the ‘n’ is equal to the number of BSs. It is allowed to allocate each of the third bands to each of the BSs.
[0057] Then, it is allowed for a BS not to share a 1 st second frequency band of the second bands, because an MS has no ability to cancel out an interferer due to having one receive antenna.
[0058] Then, two BSs can share one of the third bands with each other since a 2 nd second band of the second bands is allocated to an MS having two receive antennas, because the MS can cancel out one interferer due to having the two receive antennas.
[0059] Three BSs can share one of the third bands with each other since a 3 rd second band of the second bands is allocated to an MS having three receive antennas, because the MS can cancel out two interferers due to having the three receive antennas.
[0060] ‘N’ BSs can share one of the third bands with each other since an N-th second band of the second band is allocated to an MS having ‘N’ receive antennas. This is because the MS can cancel out (N-1) interferers due to having the ‘N’ receive antennas.
[0061] FIG. 3 is a block diagram illustrating an apparatus according to an exemplary embodiment of the present invention.
[0062] The apparatus includes a communication module 310 , a controller 320 , a storage unit 330 , and a frequency management unit 340 .
[0063] The communication module 310 , a module for communicating with another node, includes a wireless processing module, a wired processing module, and a baseband processing module (not shown). The wireless processing module converts a signal received through an antenna into a baseband signal and provides the baseband signal to the baseband module. The wireless processing module converts a baseband signal from the baseband module into a Radio Frequency (RF) signal for actual transmission over the air and transmits the RF signal through the antenna. The wired processing module converts a signal received via a wired path into a baseband signal and provides the baseband signal to the baseband module. The wired processing module converts a baseband signal from the baseband module into a corresponding wired signal for actual transmission on a wired line and transmits the wired signal via a connected wired path.
[0064] The controller 320 performs basic processing and control of the apparatus. For example, the controller 320 performs processing and control for voice communication and data communication and in addition to a general function, controls the frequency management unit 340 to decide a frequency sharing degree and receives and transmits the result to a corresponding node according to the present invention.
[0065] The storage unit 330 stores a program for controlling general operation of the apparatus and temporary data generated during program execution.
[0066] The frequency management unit 340 divides a constant frequency band into a second band and a third band according to instruction and information provision by the controller 320 and enables a BS to share the second band and the third band according to the number of BSs and the number of receive antennas of an MS. That is, the frequency management unit 340 performs a frequency allocation process described above. The frequency allocation process is described later with reference to a flow diagram of FIG. 4 .
[0067] The controller 320 can perform a function of the frequency management unit 340 . The present invention separately constructs and shows constituent elements in order to distinguish and describe respective functions of the constituent elements. The controller 320 can be constructed to process all or some of the functions of the frequency management unit 340 .
[0068] FIG. 4 is a flow diagram illustrating a frequency allocation process according to an exemplary embodiment of the present invention. “N” and “n” denote natural numbers and are equal to each other.
[0069] In FIG. 4 , the apparatus of the present invention divides a frequency band into ‘N’ second bands in step 410 . Then, the apparatus divides each of the ‘N’ second bands into ‘n’ third bands in step 420 . After that, the apparatus allocates the ‘N’ second bands for an MS having the same number of receive antennas in step 430 . Then, the apparatus allocates the ‘n’ third bands to ‘n’ BSs in step 440 . Then, the apparatus allows a BS to share a frequency suited to the number of receive antennas of an MS in step 450 and then terminates the process according to the exemplary embodiment of present invention.
[0070] A frequency reuse technique of the present invention has an advantage of the ability to improve frequency reuse capabilities by allowing a BS to share a frequency in such a manner that an MS supporting an MIMO technology can cancel out interference.
[0071] While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. | A frequency reuse apparatus and method for a Mobile Station (MS) using a multiple-antenna in a broadband wireless access communication system are provided. The method includes dividing a first frequency band into ‘N’ second frequency bands where ‘N’ equals a number of Base Stations (BSs); dividing each second frequency band into ‘n’ third frequency bands; allocating each of the ‘N’ second frequency bands according to the number of receive antennas; and allocating the third frequency bands to all of the BSs, respectively. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Applicants claim priority under 35 U.S.C. §119 of German Application No. 10 2008 055 908.3 filed Nov. 5, 2008.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a multi-part piston for an internal combustion engine, having an upper piston part and a lower piston part. The upper piston part and the lower piston part each have an inner and an outer support element, which elements delimit an outer circumferential cooling channel and an inner cooling chamber. The cooling chamber bottom has an opening.
[0004] 2. The Prior Art
[0005] A piston of this type is disclosed in European Patent No. EP 1 222 364 B1. The opening in the cooling chamber bottom allows cooling oil to flow away out of the inner cooling chamber in the direction of the piston crown, in order to lubricate the piston pin. In order to achieve this goal, the opening in the cooling chamber bottom cannot be too large, because then, the cooling oil would no longer flow away in metered manner, and its cooling effect in the inner cooling chamber would at least be reduced. This means that the cooling chamber bottom is configured essentially as a relatively wide and thin circumferential ring land that extends approximately in the radial direction, in the upper region of the lower piston part. However, such a structure is difficult to produce. In the case of a forged lower piston part, in particular, there is the additional problem that the microstructure of the material is changed in the region of the ring land, as the result of forging.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the invention to provide a piston of the stated type, in such a manner that a good cooling effect of the cooling oil in the interior of the cooling chamber and effective lubrication of the piston pin are guaranteed, and, at the same time, the stability of the lower piston part is not impaired.
[0007] This object is accomplished according to the invention by a piston for an internal combustion engine, having an upper piston part and a lower piston part, each of the piston parts having an inner and an outer support element, which elements delimit an outer circumferential cooling channel and an inner cooling chamber. The bottom of the cooling chamber has an opening. The opening is closed off with a separate closure element, which has at least one cooling oil opening.
[0008] The configuration according to the invention makes it possible to provide a very large opening in the cooling chamber bottom, so that the relatively wide and thin circumferential ring land, which extends approximately in the radial direction, is eliminated. Instead, only a narrow circumferential structure for holding the closure element is required. As a result, the stability of the lower piston part is maintained even if it is a forged part. The at least one cooling oil opening in the closure element provided according to the invention also allows significantly better and more precise metering of the cooling oil that flows away in the direction of the piston pin.
[0009] The closure element preferably has two or more cooling openings, so that a very precisely metered amount of cooling oil can flow away out of the inner cooling chamber, in the direction of the piston crown. The closure element can be produced from any desired material. For example, a spring steel sheet metal has proven to be well suited.
[0010] The at least one cooling oil opening in the closure element can be configured as a usual round opening, or, for example, also as a slit that extends from the edge of the closure element toward the inside.
[0011] A preferred further development provides that the closure element is held, in clamped manner, in at least one engagement groove provided in the region of the opening of the cooling chamber bottom, by means of at least one spring element, and thus is particularly easy to install. For this purpose, the closure element can have a circumferential clamping flange or at least two spring tongues disposed on the outer edge as a spring element. In the latter case, the slits that delimit the spring tongues can serve as cooling oil openings at the same time. In another variant, however, the closure element can also be welded to the cooling chamber bottom of the lower piston part.
[0012] The opening in the cooling chamber bottom and the closure element are generally configured to be essentially round. If the opening in the cooling chamber bottom is configured to be oval or an oblong hole, it is practical if the closure element has a shape that corresponds to this. If the closure element is held in a clamped manner, it is sufficient if the closure element has at least two spring elements that lie centered opposite one another.
[0013] The upper piston part and/or the lower piston part can be cast parts or forged parts, and can be produced from a steel material, for example, particularly forged. Friction welding, for example, is a possible joining method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
[0015] In the drawings, wherein similar reference characters denote similar elements throughout the several views:
[0016] FIG. 1 shows a section through a first exemplary embodiment of a piston according to the invention, whereby the right half of the figure has been rotated by 90 relative to the left half;
[0017] FIG. 2 shows a section through another exemplary embodiment of a piston according to the invention, whereby the right half of the figure has been rotated by 90° relative to the left half; and
[0018] FIG. 3 shows a top view of a lower piston part for another exemplary embodiment of a piston according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring now in detail to the drawings, FIG. 1 shows a first exemplary embodiment of a piston 10 according to the invention, which is forged from a steel material in the exemplary embodiment. Piston 10 according to the invention is composed of an upper piston part 11 and a lower piston part 12 . Upper piston part 11 has a combustion bowl 13 , a circumferential top land 14 , and a circumferential ring belt 15 . Lower piston part 12 has a piston skirt 16 , pin bores 17 for accommodating a piston pin, and pin bosses 18 . Upper piston part 11 and the lower piston part 12 form a circumferential outer cooling channel 19 and a central inner cooling chamber 21 . Cooling chamber bottom 22 of cooling chamber 21 is provided with a relatively large opening 23 .
[0020] Upper piston part 11 has an inner support element 24 and an outer support element 25 . Inner support element 24 is disposed on the underside of upper piston part 11 , circumferentially, in ring shape, and has a joining surface 26 . Inner support element 24 furthermore forms part of the circumferential wall of inner cooling chamber 21 . Outer support element 25 of upper piston part 11 is formed below ring belt 15 , in the exemplary embodiment, and has a joining surface 27 .
[0021] Lower piston part 12 also has an inner support element 28 and an outer support element 29 . Inner support element 28 is disposed on the top of lower piston part 12 , circumferentially, and has a joining surface 31 . Inner support element 28 furthermore forms part of the circumferential wall of the inner cooling chamber 21 . Outer support element 29 is formed as an extension of piston skirt 16 in the exemplary embodiment, and has a joining surface 32 . A cooling oil channel 43 is provided in the inner support element 28 , and connects cooling channel 19 with cooling chamber 21 . Cooling oil channel 43 runs at an angle upward, proceeding from cooling channel 19 , in the direction of cooling chamber 21 .
[0022] Upper piston part 11 and lower piston part 12 were joined, in the embodiment shown, in known manner, by friction welding along joining surfaces 26 , 31 and 27 , 32 , respectively.
[0023] Opening 23 in cooling chamber bottom 22 is closed off with a closure element 33 . In the exemplary embodiment, closure element 33 is produced from a spring sheet metal, approximately 0.8 mm thick, and held in opening 23 in a clamped manner. For this purpose, a circumferential engagement groove 34 is provided in cooling chamber bottom 22 in the inner region of opening 23 . Closure element 33 is provided with slits 35 that extend radially inward, along its edge region, which slits open into a rounded part 36 . Slits 35 and rounded parts 36 serve as cooling oil openings that allow the cooling oil to flow away out of inner cooling chamber 21 in the direction of the piston pin during operation. Slits 35 and rounded parts 36 are punched out of closure element 33 in the embodiment shown.
[0024] The regions delimited by the slits 35 simultaneously represent spring tongues 37 by means of which closure element 33 is held in engagement groove 34 , in a clamped manner. For assembly, closure element 33 is pressed into opening 23 of cooling chamber bottom 22 , coming from the direction of pin bores 17 . In this connection, spring tongues 37 at first give way, and then engage into engagement groove 34 .
[0025] FIG. 2 shows another exemplary embodiment of a piston 110 according to the invention. Piston 110 has essentially the same construction as piston 10 according to FIG. 1 , so that the same structures are provided with the same reference symbols, and with regard to these reference symbols, reference is made to the description of FIG. 1 .
[0026] A significant difference from the piston 10 according to FIG. 1 consists in the fact that cooling chamber bottom 22 does not have an engagement groove in the inner region of opening 23 . Furthermore, closure element 133 that closes off opening 23 is provided, in usual manner, round openings 138 for passage of the cooling oil out of cooling chamber 21 in the direction of the piston pin. Closure element 133 consists, in the exemplary embodiment, of a metallic material, and is welded to cooling chamber bottom 22 in the region of opening 23 . For this purpose, closure element 123 has a welding flange 139 . In the region of opening 23 , cooling chamber bottom 22 is provided with a corresponding contact edge 142 for welding flange 139 , which edge runs around opening 23 .
[0027] FIG. 3 shows a top view of a lower piston part 12 for another exemplary embodiment of a piston 210 according to the invention. Piston 210 , i.e. lower piston part 12 , has essentially the same construction as piston 10 according to FIG. 1 , so that the same structures are provided with the same reference symbols, and with regard to these reference symbols, reference is made to the description of FIG. 1 .
[0028] A significant difference from the piston 10 according to FIG. 1 consists in the fact that cooling chamber bottom 22 in lower piston part 12 has an opening 223 in the approximate shape of an oblong hole opening 223 is closed off with a closure element 233 that is configured to essentially correspond to opening 223 , in order to be able to close this off completely.
[0029] In the exemplary embodiment, closure element 233 is also produced from a spring sheet metal, and held in opening 223 in a clamped manner. For this purpose, two engagement grooves 234 disposed in a centered manner and lying opposite one another are provided in cooling chamber bottom 22 , in the interior region of opening 223 . In the exemplary embodiment, closure element 233 is provided with slits 35 that are disposed centered, lying opposite one another, extending radially inward, which open into a rounded part 36 . In the exemplary embodiment, three slits 35 lie opposite one another. Slits 35 and rounded part 36 serve as cooling oil openings that allow the cooling oil to flow away out of inner cooling chamber 21 in the direction of the piston pin during operation. Slits 35 and rounded parts 36 are punched out of closure element 233 in the exemplary embodiment.
[0030] The regions delimited by slits 35 simultaneously represent spring tongues 37 by means of which closure element 233 is held in the engagement grooves 234 , in a clamped manner. For assembly, closure element 233 is pressed into opening 223 of cooling chamber bottom 22 , coming from the direction of pin bores 17 . In this connection, spring tongues 37 at first give way, and then engage into engagement grooves 234 . Regions 241 of closure element 233 that follow the clamping region make contact below opening 223 of cooling chamber bottom 22 .
[0031] In this representation, in particular, it can easily be seen that the broad, radially circumferential ring lands required in the state of the art have been eliminated.
[0032] Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention. | A multi-part piston for an internal combustion engine has an upper piston part and a lower piston part. The upper piston part and the lower piston part each have an inner and an outer support element, which elements delimit an outer circumferential cooling channel and an inner cooling chamber, whose cooling chamber bottom has an opening. The opening is closed off with a separate closure element, which has at least one cooling oil opening | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. provisional patent application Serial No. 60/281,191 filed Apr. 3, 2001.
BACKGROUND OF THE INVENTION
The present invention relates to magnetic resonance imaging systems and, in particular, to the radio frequency coils used in such systems.
Magnetic resonance imaging (MRI) utilizes hydrogen nuclear spins of the water molecules in the human body, which are polarized by a strong, uniform, static magnetic field from the main magnet system (named B 0 —the main magnetic field in MRI physics). The magnetically polarized nuclear spins generate i; magnetic moments in the human body. The magnetic moments point in the direction of the main magnetic field in a steady state, and produce no useful information if they are not disturbed by any excitation.
The generation of the nuclear magnetic resonance (NMR) signal for MRI data acquisition is accomplished by exciting the magnetic moments with a uniform radio frequency (RF) magnetic field (named B 1 field or the excitation field). The B 1 field is produced in the imaging region of interest by an RF transmit coil which is driven by a computer-controlled RF transmitter with a power amplifier. During excitation, the nuclear spin system absorbs magnetic energy, and the magnetic moments precess around the direction of the main magnetic field. After excitation, the precessing magnetic moments will go through a process of free induction decay (FID), releasing their absorbed energy and returning to the steady state. During the FID, NMR signals are detected by the use of a receive RF coil, which is placed in the vicinity of the excited volume of the human body. The NMR signal is the secondary electrical voltage (or current) in the receive RF coil that has been induced by the precessing magnetic moments of the human tissue. The receive RF coil can be either the transmit coil itself, or an independent receive-only RF coil. The NMR signal is used for producing MR images by using additional pulsed magnetic gradient fields, which are generated by gradient coils integrated inside the main magnet system. The gradient fields are used to spatially encode the signals and selectively excite a specific volume of the human body. There are usually three sets of gradient coils in a standard MRI system, which generate magnetic fields in the same direction of the main magnetic field, varying linearly in the imaging volume.
In MRI, it is desirable for the excitation and reception to be spatially uniform in the imaging volume for better image uniformity. In a standard MRI system, the best excitation field homogeneity is usually obtained by using a whole-body volume RF coil for transmission. The whole-body transmit coil is the largest RF coil in the system. A large coil, however, produces lower signal-to-noise ratio (SNR) if it is also used for reception, mainly because of its greater distance from the signal-generating tissues being imaged. Since a high SNR ratio is the most desirable in MRI, special-purpose coils are used for RF reception to enhance the SNR from the volume of interest.
In practice, a well-designed specialty RF coil should have the following functional properties: high SNR, good uniformity, high unloaded quality factor (Q) of the resonance circuit, and high ratio of the unloaded to loaded Q factors. In addition, the coil device must be mechanically designed to facilitate patient handling and comfort, and to provide a protective barrier between the patient and the RF electronics. Another way to increase the SNR is by quadrature reception. In this method, NMR signals are detected in two orthogonal directions, which are in the transverse plane or perpendicular to the main magnetic field. The two signals are detected by two independent individual coils that cover the same volume of interest. With quadrature reception, the SNR can be increased by a factor of up to the square root of 2 over that of the individual linear coils.
Most of currently available knee coils are designed to image the knee only and foot/ankle coils (e.g., U.S. Pat. No. 5,361,764) to image the foot and ankle only.
U.S. Pat. No. 5,277,183, which is incorporated herein by reference, shows a coil that performs all three functions, but the coil design makes compromises between clinical versatility and imaging performance. This coil modifies the shape of a standard birdcage coil (U.S. Pat. No. 4,680,548) for receiving the toes of the foot when the foot is placed in the knee coil. The appendant volume for receiving the toes is shaped like a chimney, and therefore the coil has a nickname of “chimney coil”. One major drawback is that the chimney coil design deviates from the optimized birdcage structure, and therefore the RF current pattern is not optimized for the best image uniformity and SNR. The second major disadvantage is that the chimney coil does not work in MRI systems with have a vertical main magnetic field. Another drawback of the chimney coil is that it does not offer enough coverage for imaging the foot and ankle without sacrificing the image quality of the knee.
SUMMARY OF THE INVENTION
A MRI RF coil for use on a human leg having a knee, ankle and foot. The coil includes a knee coil section and a foot/ankle coil section. The sections are configurable into a boot-like structure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a coil according to the invention.
FIG. 2 is a perspective view of a knee coil section according to the invention showing the top and bottom halves separated.
FIG. 3 is a perspective view of a foot/ankle coil section according to the invention.
FIG. 4 is a schematic diagram of a call identification system according to the invention.
FIG. 5 is a perspective schematic view of exemplary coil traces in a knee coil section according to the invention. The coil elements are shown spaced apart for ease of understanding.
FIG. 6 is a perspective schematic view of exemplary coil traces in a foot/ankle coil section according to the invention. The coil elements are shown spaced apart for ease of understanding.
FIG. 7 is a side elevation cross sectional view of the solenoidal coil of FIG. 6 .
FIG. 8 is a perspective view of a foot/ankle section being inserted into the bottom half of a knee section of a coil according to the invention.
FIG. 9 is a perspective view of the top half of a knee section being assembled over a foot/ankle section of a coil according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a MRI RF coil 10 includes a knee coil section 12 and an independent foot/ankle coil section 14 . Each of the sections 12 , 14 may be, for example, linear or quadrature (for quadrature reception) volume coils or coil arrays, for example a quadrature or linear knee coil section (or coil array) and a quadrature or linear foot/ankle coil coils section (or coil array).
When imaging the knee, the knee coil section 12 (FIG. 2) may be used alone without the foot/ankle coil section 14 (FIG. 3 ). When imaging the foot and ankle, both sections 12 , 14 are used and combined as a single coil 10 (FIG. 1 ). The two individual sections 12 , 14 are designed to be compatible with each other when they are used as a combination coil package. Each individual coil section or coil array can include of one, two, or more coil elements. Combined, the coil 10 allows MR imaging with all or a selected number of coil elements in both coil sections.
Referring FIG. 4, the total number of signal output cable assemblies can be one or two. In either case, the coil identification is changed by the “plug-in” of the foot/ankle coil section 14 into the knee coil section 12 . This gives the coil identification of the combined coil 10 for foot/ankle imaging. When the foot/ankle coil section 14 is removed, the knee coil section 12 gives the coil identification as the knee coil section 12 . This coil identification is read by the MRI system.
The coil 10 includes at least two RF coil elements: at least one coil element in the knee coil section 12 and at least one coil element in the foot/ankle coil section 14 . Each coil element can also be a multi-element coil array. In a preferred embodiment, there are two quadrature coil elements in each of the coil sections 12 , 14 .
Referring to FIG. 5, the coil element 16 in the knee coil section 12 may be a modified two-turn solenoid that has the center section (the crossing area) of the coil bottom inductors dropped down or away from the knee. The two inductor turns are in series. The second coil element 18 in the knee coil section may be a modified saddle coil that also has the center section (the crossing area) of the coil bottom inductors dropped down or away from the knee. The two saddle coil turns are also in series.
Referring to FIG. 6, a coil element 20 in the foot/ankle coil section 14 may be a modified two-turn solenoid that has the heel section (the crossing area) of the coil bottom inductors dropped down or away from the heel. The element 20 may be provided with an extended portion 22 that aids in imaging the ankle and is designed to extend within the knee coil section 12 during imaging of the ankle. The two inductor turns of the element 20 are in series. The side view of the coil inductors is provided in FIG. 7 . The angle A between the extended portion 22 and the foot section can be, for example, from 90 degrees to 110 degrees. The coil element 24 in the foot/ankle coil section 14 may be a bent single-turn or two-turn loop coil. The typical angle B of bending can be, for example, from 80 to 100 degrees. The bending occurs at just below the toes.
The knee coil section can be advantageously constructed with two halves (FIG. 2) (a split-top design). There may be two latch a levers 26 on the top half 28 , one on each side, located at the center in the head-to-toe direction. To unlatch or unlock the top 28 from the bottom 30 , the latch levers 26 are pulled outward. Then the top half 28 can be removed. To engage the top half 28 with the bottom 30 and lock the top 28 to the bottom 30 , the top 28 is pushed downward and the latch levers 26 pushed inward. The latch levers 26 may be, for example, spring-loaded with elastic o-rings. In the locked position after the patient is positioned, the outer surface of the latch levers may be advantageously designed flush with the coil housing outer surface.
Referring to FIGS. 8 and 9, in the knee/foot/ankle combination coil configuration, the portion 22 or the ankle portion of the foot/ankle coil section 14 may be advantageously overlapped with the knee coil section 12 . The overlapping section of the foot/ankle coil section 14 is placed inside the knee coil section 12 . Two sets of push-on connectors can be provided between the foot/ankle coil and the bottom half of the knee coil and multiple (two or more) electrical contacts within each set of connectors. There may be one set of connectors on each side of the coils. The use of the knee section 12 further increases the coverage of the ankle in this combination configuration. After the foot/ankle coil is engaged with the bottom half of the knee coil, the patient's foot and ankle will be positioned properly. Then, the top half 28 of the knee coil section 12 may be put on and locked into position before imaging.
The foot/ankle coil section 14 may be shaped like a shoe with the front open. The addition of the knee coil section 12 make the coil 10 boot-like. It is possible to design some mechanical members such as bars in the open front of the foot/ankle section 14 for different inductor designs. However, the members should be removable or opened easily for patient positioning or accepting the foot. After patient positioning, the members need to be replaced back before imaging. To immobilize the foot and ankle, soft foam pads may be used.
The coil 10 may be used to perform MRI imaging by using the knee section 12 or the foot/ankle coil section 14 independently. The two coil sections may be designed in such a way that they can be quickly disconnected from each other and either one of the coil arrays can be plugged in the MRI system by using an adapter and cable assembly. This feature allows one of the two coil sections to be used as an independent RF coil for more clinical applications.
The coil 10 optimizes the image quality in all the three anatomical regions, knee, foot and ankle.
It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited. | A MRI RF coil for use on a human leg having a knee, ankle and foot. The coil includes a knee coil section and a foot/ankle coil section. The sections are configurable into a boot-like structure. | 6 |
BACKGROUND OF THE INVENTION
The subject matter of the invention is a device for controlling the vacuum in a vacuum line system, especially for milking installations.
A device of this kind is known, having a casing which can be attached to a vacuum line by means of a pipe connection, and in which there is disposed a main valve means comprising a main valve chamber having a valve seat on its side facing the pipe connection and air inlet apertures in its outer walls, and having a main valve connected by a stem to a membrane by which the main valve chamber is separated from a control chamber. A vacuum which depends on the vacuum prevailing in the vacuum line can be applied to the control chamber, the position of the main valve with respect to its seat being dependent upon the vacuum in the control chamber. In the casing there is disposed an auxiliary valve means influencing the vacuum in the control chamber, and having an auxiliary valve which is connected to an auxiliary membrane separating two auxiliary chambers, a first of which is connected to the vacuum line and a second to the exterior, the pressure difference thus created producing a force lifting the auxiliary valve away from an auxiliary valve seat against the adjustable force of a coil spring.
A device of this kind is described, for example, in German Auslegeschrift No. 2,363,125.
Such devices are intended for the purpose of maintaining a certain given pressure constant in vacuum line systems, and especially to keep it from decreasing. This is very important especially in milking installations. The use of the device of the invention, however, is not limited to milking installations, and can also be used for the control of vacuum in any kind of vacuum line system.
The known device has the disadvantage that the closing force applied to the main valve is determined in part by a loading weight, so that the operation of the device depends to a great extent on the position in which it is installed. In another embodiment of the known device, the main valve closing force is determined in part by a coil spring, so that the opening and closing action of the main valve is greatly dependent upon the characteristic and bias of this coil spring, so that, in the case of a linear characteristic, for example, the forces required for opening increase greatly as the opening travel increases. This had a disadvantageous effect on the regulating action of the device. Furthermore, in the known device the transmission of the reference vacuum to the first auxiliary chamber of the auxiliary valve takes place through an independent conduit running outside of the device and leading into the vacuum line at a point different from the point at which the device is connected to the vacuum line. In the first place, therefore, two places must be provided for connecting the device to the vacuum line, and secondly the reference vacuum is taken from the vacuum line at a point whose distance from the point at which the regulation takes place is not negligible under certain circumstances, and this can also result in disturbances in the regulation.
SUMMARY OF THE INVENTION
The object of the invention is to improve the device of the type mentioned in the beginning such that it would be independent of its position, i.e., that it could be connected to a vacuum line in any position. Furthermore, the device is to be of compact construction, and especially it is to be able to be connected to a point on a vacuum line with only a single connection.
The object of the invention are achieved by closing off the control chamber on the side facing away from the main valve chamber with a second membrane adjoining the exterior, both membranes being attached to the casing on the one hand and on the other to a movable valve support on which the stem of the main valve is disposed, and by presenting active surfaces of different size, one to the interior of the main valve chamber and the other to the exterior, the auxiliary valve being disposed on the valve support, and the control chamber as well as the first auxiliary chamber being connected to the vacuum line by a passage running through the support, the valve stem and the main valve.
By the disposition of the control chamber between the two membranes attached to the movable support, the main valve is made to act in the manner of a differential piston. Each pressure difference between the exterior and the control chamber corresponds to a certain particular position of the main valve, and there is no need for any additional measures, such as spring loading or loading by weights, to cause the main valve to close. By the special disposition of the auxiliary valve and the delivery of the vacuum through the main valve it is brought about that no additional external connection is required for the reference vacuum.
In accordance with the invention, a variety of advantageous embodiments of the device of the invention is possible.
For example, a tube can be disposed concentrically in the passage on a portion of its length, and its outside diameter can be smaller than the inside diameter of the passage, such that a first annular passage is created between the inside wall of the passage and the outside wall of the tube, thereby providing the connection between the control chamber and the vacuum line, and the tube is carried through the auxiliary valve seat while leaving a second annular passage, and through the auxiliary valve, sealingly and fixedly joined to the latter, and is connected to the first auxiliary chamber.
In an especially advantageous embodiment, the passage can be prolonged at the end adjacent the vacuum line by means of a flexible tube passing through the connection piece into the vacuum line.
In another advantageous embodiment, the tube is carried through the entire length of the passage and is prolonged at its end adjacent the vacuum line by a flexible tube passing through the connection piece into the vacuum line.
In these two last-named embodiments it is brought about that the reference vacuum delivered to the auxiliary valve acting as a comparator is detected not in the connection itself but in the vacuum line, at a point where the turbulence has died out.
In still another especially advantageous embodiment, the control chamber is connected to the vacuum line by a fixed throttle means and can be connected by the auxiliary valve to the second auxiliary chamber in the form of a valve chamber, and the main valve is disposed with respect to its valve seat such that, when the pressure increases in the control chamber, a force is exerted on the main valve which tends to open it.
By this embodiment a device is created in accordance with the invention, in which, as will be explained more extensively below with the aid of an embodiment, the pressure in the control chamber of the main valve is controlled oppositely to the pressure in the vacuum line, i.e., when the pressure in the vacuum line further decreases, i.e., when the vacuum becomes higher, the pressure in the control chamber increases and thereby opens the main valve and the pressure in the vacuum line increases again. In systems in which an excessively great drop in the pressure in the vacuum line must be prevented under all circumstances, as in the case of milking installations, for example, this has the great advantage that the device is a "fail-safe" device, i.e., if the pressure is caused to increase in the control chamber by trouble in the valve itself, such as a break in the membrane, especially when it increases up to the atmospheric pressure, the valve will open. This feature is not to be found in known devices of this kind.
Furthermore, this embodiment has the great advantage that the device can use very low air flow rates for the regulation, so that a far better utilization of the maximum pumping power becomes possible.
The construction of the membranes as oppositely acting rolling membranes, known in themselves, has the advantage that no skewing of the device in one or another direction can take place.
BRIEF DESCRIPTION OF THE DRAWINGS
Examples of the embodiments of the device of the invention will be further explained below with the aid of the appended drawings, wherein:
FIG. 1 is a top view of a device for the regulation of the vacuum in a vacuum line system,
FIG. 2 is a cross section taken along line II--II of FIG. 1, with the main valve open,
FIG. 3 is a cross section taken along line III--III of FIG. 1, with the main valve closed, and
FIG. 4 is a cross section taken along line II--II of FIG. 1 in another embodiment of the device, with the main valve closed.
DETAILED DESCRIPTION OF THE INVENTION
The apparatus represented in FIGS. 1 to 3 has a casing 1 having a connection 2 whereby it is connected to a vacuum line 3 represented only partially in the drawings. Within the casing 1 there is disposed a main valve whose seat is at the transition between the casing 1 and the connection 2. The valve seat has an O-ring 5 which can be engaged by a main valve body 7 disposed on the side of the valve seat facing the connection 2. The valve stem 8 is brought through the valve seat 5 and is attached to a valve support 18 which is movably disposed in casing 1 and has active surfaces 18a and 18b. The inner chamber of casing 1 adjoining the connection 2 forms the main valve chamber 4 which is vented to the exterior through the air admission apertures 6. The valve support 18 is connected by a first rolling membrane 9 to the casing 1 and by a second rolling membrane 17 to a sealing ring 1a forming the upper part of the casing and mounted thereon. The sealing ring 1a is affixed to the casing 1 by means of an annular clamp 1b. The valve support 18 is movable in the axial direction, such that the rolling membranes 9 and 17 will roll against the guiding surfaces 18c and 18d. Between the two rolling membranes 9 and 17 there is a control chamber 10 which is sealed by the sealing ring 1a. The control chamber 10 is connected by a passage 10a to a passage 19 running through the valve support 18, the valve stem 8 and the main valve body 7 and emerging at the side of the main valve body 7 facing the vacuum line 3, where it terminates in an extension tube 19a. The extension tube 19a is inserted into a flexible tube 20 which passes through the connection 2 and into the vacuum line 3.
Within the valve support 18 of bipartite construction there is provided a chamber in which an auxiliary valve 11 is disposed, which is attached by a rolling membrane 12 to the valve support 18. The rolling membrane 12 divides the chamber in which the auxiliary valve 11 is disposed into a first auxiliary chamber 13a and a second auxiliary chamber 13b. The valve 11 is movable axially and cooperates with an auxiliary valve seat 14 which is in the form of an O-ring and is so disposed on the upper end of passage 19 within the valve support 18 that the upper end of passage 19 can be closed by means of the auxiliary valve 11. A tube 21 extends axially downward through the auxiliary valve 11 and through valve seat 14 into passage 19, and at its upper end it communicates through an orifice 28 with the first auxiliary chamber 13a. The diameter of this tube and its length are such that within the passage 19 two passages of annular cross section are formed, namely a first passage 16 between the main valve 7 and the entrance of connecting passage 10a into passage 19, and a second passage 22 of annular cross section between the valve seat 14 and the entry of connecting passage 10a into passage 19. The cross-sectional area of the first annular passage 16 is smaller than the cross-sectional area of the second annular passage 22.
The second auxiliary chamber 13b, which forms the valve chamber of the auxiliary valve, communicates with the exterior through an air intake passage 23, the inlet orifice of passage 23 being covered by a filter 24. The auxiliary valve 11 is urged against the valve seat 14 by a coil spring 15 disposed in the valve support 18. The bias of the coil spring 15 is variable by means of an adjusting screw 15a.
The rolling membranes 9 and 18 are clamped to the valve support 18 by means of the bolted plates 27a and 27b. On the side of valve support 18 facing the main valve chamber 4, there are also disposed the posts 26 which limit the travel of the main valve upon full opening. Guide tracks 2a are provided in nipple 2 to guide the main valve 7.
The operation of the above-described apparatus is as follows:
A vacuum is produced in vacuum line 3 by a pump which is not shown. When the pressure drops in vacuum line 3, the pressure within the control chamber 10 is also lowered through the flexible tube 20, the passage 19 and the connecting passage 10a. In like manner, the pressure in the first auxiliary chamber 13a is lowered through the flexible tube 20, passage 19, tube 21, and orifice 28. Due to the bias of the spring 15, however, at first the auxiliary valve 11 remains seated on auxiliary valve seat 14, i.e., the auxiliary valve remains closed. As a result of the vacuum in control chamber 10, the atmospheric pressure acts on the two active surfaces 18a and 18b of the valve support 18. Since the lower active surface 18a is larger than the upper active surface 18b, a force develops which ultimately brings the valve support 18 from the position shown in FIG. 2 to the position shown in FIG. 3. At the same time the main valve body 7 applies itself to the main valve seat 5 and the main valve is thus closed.
When the pressure in vacuum line 3 continues to drop and thus also the pressure in the first auxiliary chamber 13a diminishes more slowly through the orifice 28, inasmuch an atmospheric pressure prevails in the second auxiliary chamber 13b, the opening force acting on auxiliary valve 11 against the force of coil spring 15 becomes greater. When this opening force overcomes the force of the coil spring 15, the auxiliary valve 11 is lifted from auxiliary valve seat 14. Outside air can then enter into passage 19 through the intake passage 23 and the second auxiliary chamber 13b as well as the passage 22, to a certain degree. This causes the pressure in control chamber 10 to increase, and a force acts on the valve support 18 tending to open the valve, thereby lifting the main valve body 7 from the main valve seat 5 to a greater or lesser extent, depending on the pressure prevailing in the control chamber 10. As a result, the outside air passes through the air entrance apertures 6 into the main valve chamber 4 and through the connection 2 into the vacuum line, with the result that the pressure in vacuum line 3 again increases.
This operation therefore results in a regulation of the vacuum in vacuum line 3, it being possible to adjust the steady vacuum level by means of screw 15a to vary the bias of the coil spring 15.
By means of the auxiliary valve, the pressure prevailing in control chamber 10 is controlled in the above described device by the admixture of additional air. The lower the pressure in vacuum line 3 becomes, the more the auxiliary valve 11 rises from the auxiliary valve seat 14, and the more additional air is fed to passage 19 and hence to control chamber 10, i.e., the more the pressure in vacuum line 3 drops, the more the pressure increases in the control chamber 10. The regulating characteristic of the entire apparatus can be governed by appropriately dimensioning the internal cross sectional areas of the two passages 16 and 22 and of the orifice 28. At the same time, the internal cross sectional area of passage 16 must be smaller than that of the passage 22, so that no more additional air can be carried out of the passage 19 than is being fed in through the auxiliary valve. The orifice 28 produces a slightly delayed response of the auxiliary valve, thereby permitting the elimination of valve chatter.
One special property of the device described is its ability to "fail safe." This "fail-safe" quality is to be understood to mean that, in the event of trouble occurring in the device itself, the main valve will assume a certain desired position. This position, in the case of a milking installation, is the open position, because in this case the pressure in vacuum line 3 increases, which means that in no case can an unacceptably great drop of the pressure in the vacuum line 3 occur which might damage the udders of the cows. If, for example, in the case of the apparatus of FIGS. 1 to 3, one of the two rolling membranes 9 or 17 develops a leak or bursts, the pressure in the control chamber 10 will increase, possibly up to atmospheric pressure, and the result will be that main valve will reliably open.
Another property of the apparatus is that, due to the movement of tube 21 together with the auxiliary valve 11, a self-clearing action will be produced in passages 16 and 22, to protect them against clogging.
The prolongation of the passage 19 by the flexible tube 20 brings it about that the reference pressure which is fed to the first auxiliary chamber 13a is detected not within the connection 2 where turbulence might occur, but within the vacuum line 3.
The manner of the operation of the rolling membranes 9 and 17 assures that there can be no skewing in the movement of the valve support 18, and particularly no "slip-stick" action. The operation of the entire device is independent of the position of installation.
Another embodiment of a vacuum regulating device is represented in FIG. 4, which is basically similar to the device of FIGS. 1 to 3. Therefore the same reference numbers are used in FIG. 4 for the same parts as those in FIGS. 1 to 3.
The device represented in FIG. 4 differs in its operation from the device of FIGS. 1 to 3 primarily in that the control of the pressure in the control chamber of the main valve takes place in the same sense as the pressure change in the vacuum line 3.
First the structural differences from the embodiment shown in FIGS. 1 to 3 will be described. The main valve 37, when open, is within the valve chamber 4 on the side of the main valve seat 5 that faces away from the connection 2. The main valve body 37 is attached to valve support 18 by its stem 38. The control chamber 40 separated by the two rolling membranes 9 and 17 from the main valve chamber 4 and the exterior, respectively, is connected by a connecting passage 40a to a valve chamber 43c disposed within the valve support 18. The valve chamber 43c is in turn connected by the auxiliary valve seat 44, which can be closed by the auxiliary valve 41, and by an annular passage 52 to a passage 49 which is carried through the valve stem 38 and the main valve 37 and terminates in the connection 2. The auxiliary valve chamber 43c is furthermore connected by an annular passage 43d to the second auxiliary chamber 43b, which in turn is connected to the exterior through the inlet passage 23 and the air filter 24. The auxiliary valve 41 is joined by the rolling membrane 12 to the valve support 18, the rolling membrane 12 separating from one another the auxiliary chambers 43a and 43b.
The auxiliary chamber 43a is connected directly to the vacuum line 3 by a tube 51 leading directly into it. The tube 51 extends through the auxiliary valve 41, auxiliary valve seat 44 and the entire length of passage 49 through the valve stem 38 and valve body 37, and beyond the end of passage 49, into the vacuum line 3. By means of a flexible tube 50, the tube 51 is prolonged such that the vacuum delivered to the auxiliary chamber 43a is obtained directly in the vacuum line 3.
The operation of the device of FIG. 4 is as follows:
When the pressure in vacuum line 3 drops, a vacuum is produced in the first auxiliary chamber 43a on the basis of which a force acting on the auxiliary valve 41 is produced, which acts against the force of the coil spring 15 by which the auxiliary valve 41 is urged against the auxiliary valve seat 44. Depending on the adjusted bias of the coil spring 15, the auxiliary valve 41 at first does not rise from its seat 44. The control chamber 40 is connected by the connecting passage 40a, the auxiliary valve chamber 43c and passage 43d to the second auxiliary chamber 43b and hence to the exterior through the air intake passage 23, so that, when the auxiliary valve is closed, atmospheric pressure will establish itself in the control chamber 40. In this state the main valve 37 is closed on its seat 5. Then, when the pressure in the vacuum line 3 decreases to the extent that, as a result of the likewise diminishing pressure in the first auxiliary chamber 43a, the auxiliary valve 41 is unseated from valve seat 44 against the force of the coil spring 15, the pressure is also lowered in auxiliary valve chamber 43c through the passage 52 and passage 49, resulting in a lowering of the pressure in the control chamber 40.
Under the action of atmospheric pressure, the valve support 18 is subjected to the action of a force directed upwardly in FIG. 4, in the manner previously described with reference to FIGS. 1 to 3, and the main valve 37 rises from the main valve seat 5. Now the air entering through the air inlet apertures 6 into the main valve chamber 4 will pass through connection 2 into the vacuum line 3 and therefore the pressure will again increase. Thus, again, a regulation is achieved in the vacuum line 3 according to the control bias established by means of the coil spring 15. The regulatory performance of the device is determined by the cross-sectional apertures of the two passages 52 and 43d.
It is also to be noted in the device of FIG. 4 that the reference pressure fed to the first auxiliary chamber 43a is obtained at a different point in the vacuum line 3 than the control vacuum fed to the control chamber 40. In this manner any influencing of the reference vacuum by the regulating action itself is largely excluded.
Of course, it is also possible in the case of the embodiment represented in FIGS. 1 to 3 to obtain the reference vacuum at a different point than the control vacuum fed to the control chamber 10. For this purpose the tube 21 need only be brought through the entire length of the passage 19 and out of the orifice of the tube 19a. The flexible tube 20 would then be provided on the end of the prolonged tube 21.
It will be appreciated that the instant specification and example are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention. | A device for regulating the vacuum in milking installations has a main valve and an auxiliary valve. A main valve chamber is connected with the atmosphere and, through a valve seat to the vacuum line. A control chamber is closed off from the main valve chamber by a first membrane and from the atmosphere by a second membrane. Both membranes are joined to a movable support bearing the main valve body, which presents active surfaces of different size to the main valve chamber and to the atmosphere. The position of the main valve is dependent upon the pressure in the control chamber, which pressure is determined by the auxiliary valve which is disposed in the support. The auxiliary valve has two auxiliary chambers separated by an auxiliary membrane to which the auxiliary valve body is fastened. The first auxiliary chamber is connected to the vacuum line and the second auxiliary chamber is connected to the atmosphere. The position of the auxiliary valve is dependent upon the pressure difference in the auxiliary chambers and the force of an adjustable spring acting on the auxiliary valve body. The control chamber and first auxiliary chamber are connected to the vacuum line by a passage disposed centrally thereof. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of coating molded plastics articles and to articles obtainable by this method.
2. Description of the Related Art
Molded plastics articles, especially hollow articles such as bottles, canisters or tanks, frequently exhibit considerable permeation, especially to small organic molecules. To reduce this permeation it is possible to modify the surface of such hollow articles, especially plastic fuel tanks (PFTs) and fuel oil tanks, in a variety of ways. A widespread example is the fluorination or sulfonation of the container surface (Forming barrier layers in hollow plastics articles, in: Plastverarbeiter 37 (6), VDI-Verlag 1986). Modifications of this kind lead to a substantially reduced permeation to, for example, the methanol which is often present in fuels. For industrial use, however, this permeation barrier must possess long-term stability and must withstand mechanical loads over long periods of time. It is in this respect, however, that the methods known to date for the surface treatment of such molded plastics articles leave much to be desired.
SUMMARY OF THE INVENTION
It is an object of the present invention to find a method of coating molded plastics articles which provides long-term prevention of the permeation of relatively small organic molecules, such as methanol, so that only a small rise in permeation is found even after long-term mechanical loading.
We have found that this object is achieved by a method of coating molded plastics articles which comprises first of all fluorinating, sulfonating, oxidizing or otherwise activating the surface of the articles and then covering them with a silane coating material.
We have also found molded plastics articles which are obtainable by this method.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The molded plastics articles that can be coated by the novel method can have been produced from various plastics. Examples of suitable basic materials are polyethylene, polypropylene, polyethylene terephthalate, polyamide and PVC. It is preferable for the molded plastics articles to be coated to consist essentially of polyethylene, especially of relatively high-density polyethylene (HDPE). In addition to pure plastics, blends of the abovementioned plastics with one another or with further components are also suitable. In addition, composite structures comprising layers of different plastics or fibers are suitable as substrates for the novel coating method.
The novel method is suitable with particular advantage for the coating of PFTs. Many countries require PFTs to meet defined emission limits. Long-term compliance with these limits, even after mechanical loading, can be achieved by means of a novel coating method.
In accordance with the novel coating method the surface of the molded plastics article, especially that surface which comes into contact with a permeable substance such as methanol, is first of all conventionally fluorinated, sulfonated, oxidized or otherwise activated. The term activation here is intended to denote those processes which affect the hydrophilicity or microstructure of the plastics surface in such a way that the subsequent coat has adequate adhesion.
Examples of suitable fluorination techniques and sulfonation techniques are described in the article Forming barrier layers in hollow plastics articles, in: Plastverarbeiter 37 (6), VDI-Verlag 1986, pp. 107-117 and 97-107, respectively. Fluorination in particular is an appropriate surface treatment for this first step of the method. In addition, the plastics surface can be activated by, for example, oxidation, for instance by flaming, or by plasma treatment under the action of electrical discharge, as is customary, for instance, for activating polypropylene bumpers for automobiles.
The surface of the molded article which has been pretreated in this way is subsequently covered with a silane coating material. This can be done using all customary commercial silane coating materials. Preference is given to the use of those silane coating materials which are able to lead to a crosslinked structure; generally, therefore, to silane compounds which include not only the silane groups but also further functional groups, such as vinylic double bonds, isocyanate groups or oxirane groups. A particularly suitable silane coating material is one which comprises silanes of the formula I ##STR1## where: A is C 1 -C 20 -alkylene, in which nonadjacent methylenes other than those in positions α- and ω can be replaced by oxygen in ether function, and
R is C 1 -C 4 -alkyl.
Suitable linkers A are methylene, ethylene and/or straight-chain or branched propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene, nonadecylene and eicosylene.
In these alkylene linkers it is possible for methylenes--except for the end ones--to be replaced by oxygen in ether function. Linkers A of this kind are preferably derived from ethylene oxide or propylene oxide, i.e. they contain polyethylene glycol units or polypropylene glycol units. A particularly preferred linker A has the structure --CH 2 --O--CH 2 --CH 2 --.
The radicals R preferably are methyl, but can also be ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.
A preferred silane compound I is the compound ##STR2##
Particularly effective silane coating materials are those which can be converted by crosslinking into a stable network. Compounds able to bring about such crosslinks, for example in combination with the silane compounds I, are, for example, diamino, dithio or dihydroxy compounds, the latter being preferred. A particularly suitable crosslinking dihydroxy compound is 2,2-p-hydroxyphenylpropane, known as bisphenol A.
For coating the plastics surface which has been pretreated by fluorination or sulfonation, the silane compound is generally first converted to the corresponding siloxane compound using a stoichiometrically calculated amount of water in the presence of a little acid. To this mixture there is then added a solution of the crosslinking compound in organic solvent, and reaction takes place in the presence of a catalyst.
Particularly suitable solvents are highly volatile polar solvents such as acetone, methanol, ethanol, n-propanol and especially isopropanol.
Suitable catalysts are basic compounds, especially tertiary amines; methylimidazole is used with particular preference. The amount of catalyst depends on the amount of crosslinking compound. Catalysts and crosslinking compounds are generally employed in a molar ratio of from 0.05:1 to 1:1, preferably from 0.1:1 to 0.5:1.
The mixture of the hydrolyzed silane, the crosslinking compound, the solvent and the catalyst is intimately mixed and can then be applied in a variety of conventional ways to the plastics surface, for example by dipping, spraying, rolling or spreading. Coating preferably takes place by dipping.
Coating and also curing can be performed at various temperatures, for example from 10° C. to 150° C., preferably from 20° C to 130° C., with higher temperatures, for instance from 80 to 140° C., being particularly advantageous for curing and drying.
Drying can also be accelerated by reducing the pressure; generally, however, all operations are carried out at ambient pressure. Adequate ventilation is advantageous for rapid and uniform drying.
The molded plastics articles obtainable by the novel method exhibit very low permeation of organic solvents, especially methanol. Furthermore, this low permeation shows little if any increase even after long-term mechanical loading.
The invention is illustrated by the following examples.
EXAMPLES
Example 1
Preparing a Silane Coating Material
1.35 ml of 0.05 N HCl (corresponding to about 0.075 mol of water) were added slowly with stirring to 19.1 g (0.1 mol) of glycidyloxypropyltrimethoxysilane. The mixture was stirred for one hour without cooling and then combined with a solution of 9.12 g (0.04 mol) of bisphenol A and 0.82 g (0.01 mol) of N-methylimidazole in 15 ml of isopropanol. This mixture was stirred at 25° C. for 2 hours more and processed after about 5 hours up to not more than 20 hours.
Example 2
Coating Polyethylene Bottles
250 ml polyethylene bottles (manufacturer: Haltermann, Hamburg) were fluorinated by off-line fluorination. The inside of the bottles was then carefully coated by introducing 50 ml of silane coating mixture from Example 1 and inclining the bottles, and then excess coating material was discarded. The solvent was evaporated off by heating at 90° C. for 10 minutes, and then the bottles were dried at 80° C. in an oven for 5 hours.
Example 3
Investigating the permeation behavior of polyethylene bottles coated in accordance with the invention in comparison with bottles not treated in accordance with the invention.
The coated polyethylene bottles from Example 2 were filled with 100.0 g of the test medium FAM-B (in accordance with DIN 51684, manufacturer Haltermann, Hamburg) and were sealed with a PE screw cap and rubber seal. The test bottles were weighed and shaken at different temperatures for 30 days. Subsequently, the decrease in weight as a result of permeation was determined by weighing the bottles again. The result is shown in the following table:
______________________________________ Permeation at Permeation atTreatment of test bottle 25° C. 40° C.______________________________________untreated (comparison 17.1% 42.1%example)only silane coating 20.9% 44.8%(comparison example)only fluorination 0.6% 4.3%(comparison example)fluorination + 0.2% 1.2%silane coating______________________________________
Example 4
The permeation experiment of Example 3 was carried out using the test medium CEC 85 (from Haltermann, Hamburg). The table below shows the result:
______________________________________ Permeation at Permeation atTreatment of test bottle 25° C. 40° C.______________________________________untreated (comparison 24.0% 56.4%example)only silane coating 29.3% 58.5%(comparison example)only fluorination 0.02% 0.06%(comparison example)fluorination + 0.02% 0.02%silane coating______________________________________ | A method of coating molded plastics articles which comprises first of all fluorinating, sulfonating, oxidizing or otherwise activating the surface of the articles and then covering them with a silane coating material. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to a paper web feed device in a cigarette production machine.
In cigarette production machines, it is known to form the outer cigarette covering from one or more paper webs fed by means of a continuous feed device through a loading station, in which a continuous stream of shredded tobacco is fed onto each web.
In the said known feed devices, each paper web is advanced through said loading station supported by a conveyor, immediately upstream of which there is disposed a suction roller arranged to give the web the necessary forward thrust for unwinding the web from a reel and for passing it, before reaching said conveyor, through a series of devices comprising inter alia a printing unit which prints inscriptions on the web.
The printing units used in production machines normally suffer from starting difficulties in the sense that when production is resumed after each stoppage of the production machine, the print is defective for a time period which is certainly of limited duration but is such as to result in the production of some thousands of defective cigarettes, which have to be discarded and then destroyed in order to recover the tobacco used in them.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a paper web feed device which, on each resumption of production, enables that portion of the paper web containing defective print to be directly eliminated, so as to prevent the formation of defective cigarettes and avoid the cost of recovering their tobacco.
Said object is attained according to the present invention by a paper web feed device in a cigarette production machine, comprising a suction roller for advancing at least one paper web along a first path, a loading station disposed along said first path downstream of said suction roller in order to feed a continuous stream of shredded tobacco onto said web, and a conveyor disposed along said first path for guiding said web through said loading station, characterised by further comprising selectively operable deviator means for separating said web from a portion of the periphery of said suction roller and deviating it along a second path, and removal means cooperating selectively with said suction roller in order to detach and remove the portion of said web fed along said second path.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described hereinafter with reference to the accompanying drawings, which illustrate a non-limiting embodiment thereof, and in which:
FIG. 1 is a diagrammatic illustration, with parts removed for clarity, of a production machine provided with a feed device constructed in accordance with the present invention; and
FIGS. 2, 3 and 4 are diagrammatic illustrations to an enlarged scale of the feed device of FIG. 1 in three successive operating positions.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a cigarette production machine, indicated overall by 1 and comprising a base 2, on which a reel 3 is rotatably mounted.
A paper web 4 for forming the outer covering of a continuous cigarette rod 5 is unwound from the reel 3.
Starting from the reel 3, the web 4 unwinds in contact with two deviation rollers 6 and 7, and by means of a feed device indicated overall by 8 and disposed immediately downstream of the roller 7 is fed through a printing unit 9 disposed between the rollers 6 and 7.
The device 8 comprises a motorised suction roller 10, which is supported by the base 2 and rotates anticlockwise about its axis.
As shown in FIGS. 2 to 4, the roller 10 has a perforated rotatable outer shell 11, which defines an inner chamber 12 communicating with air suction conduits 13.
The roller 10 is disposed at the inlet end of a forming bench 14 for the rod 5, this bench being supported by the base 2 in a substantially horizontal position and supporting the upper branch 15 of an endless conveyor 16 forming part of the device 8 and comprising a lower branch 17 passing about two end rollers 18 and 19 and about three intermediate rollers 20, 21 and 22, of which the roller 21 is a drive roller.
The upper branch 15 of the conveyor 16 is arranged to guide the web 4 through a loading station 33, in which a continuous stream or layer 24 of shredded tobacco is fed onto the web 4 by a conveyor 25 which emerges from a tobacco feed device 26. The branch 15 is also arranged to guide the web 4 through a bar 27, along which the web 4 is folded transversely about the layer 24 to form the rod 5.
As shown in particular in FIGS. 2 to 4, the device 8 further comprises a removal device 28 comprising a lever 29 pivoted about a first axis 30 parallel to the axis of the suction roller 10 and arranged to rock about said axis 30 under the thrust of actuator means comprising an actuator device 31 coaxial to the axis 30.
Connected to the free end of the lever 29 there is a support member constituted by a support roller 32 mounted idly on the lever 29 so as to rotate relative to this latter about a second axis 33 parallel to the axis 30. The roller is a support roller for a knife 34 extending radially outwards from the roller 32 substantially towards the roller 10, and for suction means comprising a suction unit 35 opening into the outer surface of the roller 32 in a position adjacent to the knife 34.
From opposite ends of the lever 29 there extend two appendices 36 and 37, the first of which is rigidly connected to the lever 29 and extends from a point on this latter close to the axis 30 towards the periphery of the suction roller 10, and the second of which is rigid with the roller 32 and extends outwards from a point on the outer periphery of the roller 32 disposed in a position substantially opposite the knife 34. The free ends of the appendices 36 and 37 are connected together by an actuator means of elastic type constituted by a spring 38, which operates under tension and extends transversely to the axis of the lever 29 in order to cause the roller 32 to undergo a clockwise rotation about the axis 33. The action of the spring 38 is opposed by stop means comprising a stop element 39 normally engaged slidably by the appendix 37.
The device 8 also comprises a guide wall extending above part of the roller 10 and above the removal device 28 to define a first channel 41 extending about the roller 10 towards the loading station 23, and a second channel 42 extending about the roller 32 towards the discarding station, not shown, for the web 4.
The device 8 finally comprises a deviator device 43 disposed in a fixed position within the chamber 12 of the roller 10 and comprising compressed air feed means constituted by the output duct 44 of a compressed air feed circuit 45, this duct being directed radially towards the shell 11 and substantially towards the roller 32, and communicating with the outside through the ducts 13 which become successively aligned with said duct 44 during the rotation of said shell 11.
In use, on starting the production machine 1, the web 4 unwinds normally along a first path defined by the periphery of the rollers 6, 7 and 10, and is disposed with its end on the bench 14. When the suction roller 10 is started, the deviator device 43 becomes simultaneously activated, with the emission through the duct 44 of a blast of compressed air which separates the web 4 from a part of the periphery of the shell 11 and deviates it along a second path extending along the channel 42 and about the removal device 28. When the machine 1 is operating normally and the operator sees that the inscription printed on the web 4 by the printing unit 9 is correct and perfectly legible, he operates the actuator device 31, which causes the lever 29 to rotate anticlockwise from its normal rest position shown in FIG. 2 in which the roller 32 is kept separated from the roller 10 by the engagement of the appendix 37 with the stop element 39 under the thrust of the spring 38.
The operation of the actuator device 31 causes the appendix 37 to slide along the stop element 39, which keeps the roller 32 in an angularly fixed position relative to the lever 29 until the cutting position shown in FIG. 3 is reached, in which the knife 34 comes into contact with the web 4 unwinding along the roller 10. The attaining of the said cutting position, in which the web 4 is cut transversely to its axis, leads to deactivation of the deviator device 43, disengagement of the appendix 37 from the stop element 39, and activation of the suction device 35. Consequently, the knife 34 cuts the web and snaps upwards simultaneously by the effect of the clockwise rotation impressed on the roller 32 by the spring 38.
The web 4 which remains embracing the shell 11 is fed upwards by it along said first path extending along the bench 14 and through the loading station 23, whereas that portion of web 4 cut off by the knife 34 is retained by the suction device 35 in contact with the periphery of the roller 32. For this purpose, the suction device 35 is suitably disposed along the periphery of the roller 32 downstream of the knife 34 in the direction of rotation of the roller 32.
At a later stage, the operator manually returns the removal device 28 to its rest position of FIG. 2.
The use of the described feed device 8 leads to numerous advantages, of which the most important is that it prevents a defective web portion from reaching the loading station 23. During the entire time in which the web 4 is deviated along the channel 42, the tobacco fed by the conveyor 25 falls directly onto the conveyor 16, and is fed by this latter to a discharge container, not shown. In this manner, it is not necessary to destroy defective cigarettes, and the discarded tobacco can be immediately returned to the cycle.
The feed device 8 also has the advantage of forming a perfect cut at the front end of the web 4, so reducing substantially to zero the possibility of said end becoming folded and sticking during its advancement along the bench 14. This advantage is particularly apparent where the feed device 8 is used, with obvious modifications, on a double rod machine such as that described in U.S. Pat. No. 4,336,813 of the present applicant, in which two webs 4 are fed. | In a cigarette production machine, a device for feeding at least one paper web along one or other of two paths, the first of which extends through a station for loading a continuous stream of shredded tobacco onto said web, and the second of which is a discard path; that portion of the web extending along said second path being cut and removed by a selectively operable removal device. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to the detection of wtGSTO1 and mutGSTO1 enzymes. Specifically, the invention describes novel immunogens, novel antibodies and methods for detecting wtGSTO1 and mutGSTO1 enzymes, and their use in disease research, diagnosis and treatment.
BACKGROUND
[0002] Glutathione transferases (GSTs) are a multi-gene enzyme family which through catalyzing a number of distinct glutathione dependent reactions play critical roles in providing protection against electrophiles and products of oxidative stress. Multiple cytosolic and membrane-bound GST isoenzymes with divergent catalytic and non-catalytic binding properties are found in all eukaryotic species. The mammalian cytosolic GSTs are made up of Alpha (A), Mu (M), Omega (O), Pi (P), Sigma (S), Theta (T) and Zeta (Z) families (Strange et al., 2001). The most recently discovered class of cytosolic GSTs, the Omega class (GSTO1 and GSTO2), are characterised by a unique N-terminal extension and a cysteine residue in the active site, which is distinct from the tyrosine and serine residues associated with other GST classes. GSTO1 (Board et al., 2000) exhibits glutathione-dependent thiol transferase and dehydroascorbate reductase activites characteristic of glutaredoxins and which are not associated with other GSTs. The polypeptide consists of 241 amino acids with a predicted MW of 27.5 kDa but migrates at approximately 56 kDa suggesting it forms dimers under native conditions (Board et al., 2000). The structure of recombinant GSTO1 has been solved at 2 Angstrom resolution (NCBI Protein Database: 1EEM; Board et al., 2000). Expression of GSTO1 is abundant in a wide range of normal tissues including liver, macrophages, glial cells and endocrine cells, as well as myoepithelial cells of the breasts, neuroendocrine cells of the colon, fetal myocytes, hepatocytes, biliary epithelium, ductal epithelium of the pancreas, Hofbauer cells of the placenta and follicular and C-cells of the thyroid (Yin et al., 2001). This widespread expression and conserved sequence suggests that GSTO1 may have a significant house-keeping role and biological functions distinct from other GSTs.
[0003] The literature contains numerous reports on the role of GSTs in various stages of disease progression and treatment. Whereas the role of GSTs is largely beneficial in deactivating and detoxifying potentially dangerous chemicals, it appears that sometimes they have a detrimental effect in the body. For instance, over-expression has been linked with various forms of cancer, for example GSTO1 may be up-regulated in both colorectal (Liu et al., 2007) and pancreatic cancer (Chen et al., 2009). Over-expression of GSTO1 is also correlated with the onset of drug resistance of cancer cells. This may be the result of an association with the activation of survival pathways (Akt and ERK1/2) and inhibition of apoptotic pathways such as JNK1 and protection against cisplatin induced apoptosis (Piaggi et al., 2010).
[0004] Genetic variation in GSTs has been reported to represent a risk factor for a variety of diseases including many forms of cancer. A single nucleotide polymorphism (SNP) at base 419 (419C>A) of GSTO1 results in an alanine to aspartate substitution in amino acid 140 (A140D). Tanaka-Kagawa et al., (2003) functionally characterised recombinant GSTO1 Ala140Asp variants and discovered that enzyme activity decreased from that of WT (Ala/Ala) for particular substrates. This change in activity is a likely contributor to this SNPs role in disease. Polymorphisms in GSTO1 affecting the enzymes ability to metabolise inorganic arsenic have also been found (Chung et al., 2011; Agusa et al., 2008), leading to differences in individuals susceptibility to arsenic toxicity. The GSTO1 A140D polymorphism could play an important role as a risk factor for the development of heptacellular carcinoma, cholangiocarcinoma and breast cancer (Marahatta et al., 2006). The presence of WT (Ala/Ala) is more likely amongst cases of advanced stage breast cancer (Purisa et al., 2008; Chariyalertsak et al., 2009). The GSTO1 A140D polymorphism has also been associated with the risk of acute lymphoblastic leukaemia (ALL) in children and may also be involved in development of the disease (Pongstaporn et al., 2009). A role in chronic obtrusive pulmonary disease (COPD) has also been proposed (Harju et al., 2007).
[0005] Studies also suggest that GSTO1 is a risk indicator for Alzheimer's disease (AD) and Parkinson's disease (PD). Li et al., (2003) reported a difference in the gene expression of GSTO1 between AD patients and controls and that the single polymorphism rs4925 (equivalent to the Ala140Asp mutation) was linked to later age-at-onset (AAO) of both AD and PD. Kolsch et al., (2004) also found that GSTO1 polymorphisms were associated with an earlier AAO and increased the risk of vascular dementia and stroke. Although these contrasting findings could suggest that the SNP is not the causal factor in AAO, an association is present and warrants further investigation into its use as a marker. A recent study also supports a role for the GSTO1 Ala140Asp SNP in sporadic AD (Capurso et al., 2010) which is the most common form of AD. Wahner et al., (2007) found a 32% risk reduction for PD among subjects carrying one or more GSTO1 variant allele compared to the wild type.
[0006] Circumstantial evidence further supporting GSTO1 as having a role in neurodegenerative disorders includes cellular co-localization with IL-1β, which is over-expressed in the brains of both AD and PD patients (Griffin & Mrak, 2002; Czlonkowska et al., 2002) and is a fundamental component of the inflammatory response that is proposed to contribute to the pathogenesis of both AD and PD. Chronopoulou & Labrou (2009) have hypothesised that it is the dehydroascorbate reductase role of GSTO enzymes in the brain which is the basis of their genetic link to AAO in AD and PD.
[0007] It is evident from the primary literature that further research as to the role of WT and mut GSTO1 in disease is desirable and an analytical method which facilitates this is required. Single nucleotide polymorphisms (SNPs) are the most abundant form of genetic variation in humans and are associated with differences in disease risk, susceptibility, progression and success of treatment. Genotyping of SNPs is important in disease diagnosis and prognosis and is a key driving force in the expanding sector of personalized medicine. Genotyping techniques which are underpinned by the polymerase chain reaction (PCR) are costly and time-consuming and only enable a ‘risk analysis’ approach to disease diagnostics. In vitro protein detection includes techniques based on electrophoresis, mass spectrometry and antibodies, but each has potential weaknesses with respect to the current problem of wtGSTO1 and mutGSTO1 protein discrimination, in which the structural difference is a single amino acid (out of the 241 of the full protein). For example, electrophoresis is likely to be insufficiently sensitive, mass spectrometry is unlikely to produce distinctive fragmentation patterns, and antibodies to either wild type or mutant are likely to cross-react.
[0008] The inventors describe herein an antibody with surprising specificity for wtGSTO1.
REFERENCES
[0000]
Agusa, T. et al., (2008). Genetic Polymorphisms Influencing Arsenic Metabolism in Human: Evidence from Vietnam. Interdisciplinary Studies on Environmental Chemistry—Biological Responses to Chemical Pollutants , Eds., Murakami, Y., Nakayama, K., Kitamura, S.-I., Iwata, H., and Tanabe, S. pp. 179-185.© by TERRAPUB, 2008.
Board, P. G. et al., (2000). Identification, Characterization, and Crystal Structure of the Omega Class Glutathione Transferases. The Journal of Biological Chemistry, 275, 24798-24806.
Capurso, C. et al., (2010). Polymorphisms in Glutathione S-Transferase Omega-1 Gene and Increased Risk of Sporadic Alzheimer Disease. Rejuvenation Research -Not available-, ahead of print. doi:10.1089/rej.2010.1052.
Chariyalertsak, S. et al., (2009). Role of glutathione S-transferase omega gene polymorphisms in breast-cancer risk. Tumori, 95: 739-743.
Chen, J-H. et al., (2009). Comparative proteomic analysis of differentially expressed proteins in human pancreatic cancer tissue. Hepatobiliary & Pancreatic Diseases International, 8, 193-200.
Chronopoulou, E. G. and Labrou, N. E. (2009). Glutathione Transferases: Emerging Multidisciplinary Tools in Red and Green Biotechnology. Recent Patents on Biotechnology, 3 (3), 211-223(13).
Chung, C-J. et al., (2011). Gene polymorphisms of glutathione S-transferase omega 1 and 2, urinary arsenic methylation profile and urothelial carcinoma. Science of The Total Environment, 409 (3), 465-470.
Czlonkowska, A. et al., (2002) Immune processes in the pathogenesis of Parkinson's disease—a potential role for microglia and nitric oxide. Medical Science Monitor., 8, RA165-RA177.
Griffin, W. S, and Mrak, R. E. (2002) Interleukin-1 in the genesis and progression of and risk for development of neuronal degeneration in Alzheimer's disease. Journal of Leukocyte. Biology., 72, 233-238.
Harju, T. H. et al., (2007). Glutathione S-transferase omega in the lung and sputum supernatants of COPD patients. Respiratory Research, 8 (48).
Kölsch, H. et al., (2004). Polymorphisms in glutathione s-transferase omega-1 and AD, vascular dementia, and stroke. Neurology, 63, 2255-2260.
Li, Y-J. et al., (2003). Glutathione S-transferase omega-1 modifies age-at-onset of Alzheimer disease and Parkinson disease. Human Molecular Genetics, 12 (24), 3259-3267.
Liu, L et al., (2007). Proteomic analysis of Tiam1-mediated metastasis in colorectal cancer. Cell Biology International, 31 (8), 805-814.
Marahatta, S. B. et al., (2006). Polymorphism of glutathione S-transferase Omega gene and risk of cancer. Cancer Letters, 236 (2), 276-281.
Piaggi, S., et al., (2010). Glutathione transferase omega 1-1 (GSTO1-1) plays an anti-apoptotic role in cell resistance to cisplatin toxicity. Carcinogenesis, 31 (5): 804-811.
Pongstaporn, W. et al., (2009). Polymorphism of glutathione S-transferase Omega gene: association with risk of childhood acute lymphoblastic leukemia. Journal of Cancer Research and Clinical Oncology, 135 (5), 673-678.
Purisa, W. et al., (2008). Association between GSTO1 Polymorphism and Clinicopathological Features of Patients with breast cancer. Thai Cancer Journal, 28 (4) 185-189.
Strange, R. C. et al., (2001). Glutathione-S-transferase family of enzymes. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 482 (1-2), 21-26.
Tanaka-Kagawa, T. et al., (2003). Functional characterization of two variant human GSTO1-1s (Ala140Asp and Thr217Asn). Biochemical and Biophysical Research Communications, 301 (2), 516-520.
Wahner, A. D. et al., (2007). Glutathione S-transferase mu, omega, pi, and theta class variants and smoking in Parkinson's disease. Neuroscience Letters, 21; 413(3): 274-278.
Yin, Z-L. et al., (2001) Immunohistochemistry of Omega Class Glutathione S-Transferase in Human Tissues. Journal of Histochemistry & Cytochemistry, 49 (8), 983-987.
US Patent Application—US2008/0318229 —Method for diagnosing Neuro-degenerative Disease
SUMMARY OF THE INVENTION
[0031] The invention describes a novel monoclonal antibody specific to wtGSTO1 which enables immunoassay methods for the detection and determination of wtGSTO1 and mutGSTO1. The immunoassays have application, for example, in disease research. The invention is underpinned by a novel immunogen which enables the production of said antibodies.
DRAWINGS
[0032] FIG. 1 A cross-reactivity study for the cell line GST1.1H7.D2.E2.D7.D5.G2.F2. A supernatant assay was used; ELISA plates were coated with recombinants and detected via anti-species HRP. <0.1% cross-reactivity with mutGSTO1 was found.
[0033] FIG. 2 wtGSTO1 Sandwich assay.
[0034] FIG. 3 Amino acid sequences of wtGSTO1 (SEQ ID NO 3) and mutGSTO1 (SEQ ID NO 4). Peptides used in immunogen preparations are highlighted.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Unless otherwise stated technical terms are used according to the conventional usage as known to those skilled in the art.
[0036] The first aspect of the invention relates to a polypeptide hapten comprising the structure:
[0000] Lys-Glu-Asp-Tyr-Ala-Gly-Leu-Lys (SEQ ID NO 1)
attached to a cross-linking group.
[0037] Most preferably the polypeptide hapten is of the structure:
[0000] (SEQ ID NO 2) Cys-Lys-Glu-Asp-Tyr-Ala-Gly-Leu-Lys
wherein the cross-linking group is attached to the sulphur atom of Cys.
[0038] The term “hapten” as used herein describes a pre-immunogenic molecule that stimulates antibody production only when conjugated to a larger carrier molecule. The terms “peptide” and “polypeptide”, can be used interchangeably and designate a chain of amino acid based polyamides. The chain can vary in length anywhere from 2 amino acids to 100 or more amino acids. Preferably the peptide is 5-12 amino acids in length and spans the region containing the 140 th amino acid in the peptide sequence for the full native GSTO1 protein. Most preferably the polypeptide is 9 amino acids in length and incorporates a terminal cysteine residue. The sulphur atom of the cysteine residue can be conjugated to a large carrier molecule via a crosslinking agent, to form an immunogen. It will, however, be appreciated that the haptens of the invention may be conjugated to a large carrier molecule, optionally via a crosslinking agent, via other residues. For example, one of the Lys residues (either C or N terminal), the Asp residue, or the Glu residue may be used to conjugate to a large carrier molecule, optionally via a crosslinking group. Preferably, conjugation via the Cys residue is preferred.
[0039] The term “A140D” refers to the substitution at the 140 th amino acid position on the wild type GSTO1 protein sequence (NP — 004823), caused by the single nucleotide polymorphism at base 419 (419C>A; NG — 023362) in GSTO1 wherein the wild type condition (wt) has alanine (A) at this amino acid position while the mutant (mut) has aspartic acid (D). An individual can be homozygous Ala/Ala or Asp/Asp or heterozygous Ala/Asp.
[0040] A second aspect of the current invention relates to an immunogen used in the preparation of said antibody which consists of a carrier molecule coupled to the polypeptide amino acid sequences described above. The term “immunogen” as used herein, describes an entity that induces an immune response such as production of antibodies or a T-cell response in a host animal The term “carrier molecule” refers to a molecule to which a hapten or antigen can be bound to impart immunogenic properties to the hapten or antigen. The term “carrier molecule” may be used interchangeably with the terms “carrier”, “immunogenicity conferring carrier molecule” and “antigenicity conferring carrier material”. Suitable carriers include proteins such as bovine serum albumin, bovine thyroglobulin (BTG), ovalbumin, hemocyanin and thyroglobulin molecules as well as liposomes, synthetic or natural polymers and synthetically designed organic molecules. BTG is a preferred carrier. Crosslinking of peptides to proteins to form an immunogen is well known in the art; the term “crosslinker” as used herein is any bifunctional molecule able to covalently join the peptide of the invention to an immunogenicity conferring carrier molecule. A suitable crosslinker is maleimide, or a maleimide derivative, for example when BTG-maleimide is used to form a hapten-carrier (BTG) conjugate via the cysteine residue. In this case, the peptide is coupled to a BTG maleimide carrier through the addition of a non-native cysteine. Although maleimides are the preferred cross-linking group, coupling with the sulfhydryl group of cysteine, other cross-linking groups which could couple this group on the cysteine include haloacetyls and pyridyldisulfides. As discussed above, the Lys residues (either C or N terminal), the Asp residue, or the Glu residue may alternatively be used to conjugate to a large carrier molecule, optionally via a crosslinking group, to form an immunogen. For example, a primary amine group on the side chain of lysine (Lys) could be coupled using a cross-linker selected from N-hydroxysuccinimide esters, imidoesters, PFP esters or hydroxymethyl phosphine. As another example, a carboxyl group on the side chain of aspartic acid (Asp) or glutamic acid (Glu) could be coupled using a carbodiimide cross-linker, EDC or DCC. However, in one preferred embodiment, the conjugation, preferably using a BTG-maleimide, occurs via the cysteine (Cys) residue, as it is desirable to attach the cross-linker to one end of the peptide so that the full sequence is exposed for recognition by the immune system.
[0041] A third aspect of the present invention describes an antibody which specifically binds to wild type (wt) GSTO1. The term “antibody” refers to an immunoglobulin or immunoglobulin-like molecule, in a preferred embodiment of the current invention the antibody is a monoclonal antibody but the skilled person will understand that any type of immunoglobulin molecule or fragment thereof can be used, for example polyclonal antibodies, Fab fragments, scFv fragments and any other antigen binding fragments all of which fall within the scope of the current invention. Monoclonal antibodies may be produced by methods known to those skilled in the art, such as but not limited to the method described herein. Any suitable host animal may be used for example, but not limited to sheep, rabbit, mouse, guinea pig or horse. The preferred animal used for immunisation in the current invention is a sheep. Freund's complete adjuvant was used as an immunopotentiator in the primary immunizations while Freund's incomplete adjuvant was used in all subsequent boosts. Those skilled in the art will know that any suitable immunopotentiator can be used in the initial immunization and any further boosts.
[0042] A further aspect of the invention is a kit comprising the antibody (or antibodies) of the invention.
[0043] Another aspect of the current invention relates to a method of detecting and/or determining or recovering wtGSTO1 in a sample. The term “detecting” refers to qualitatively analysing for the presence or absence of a substance, while “determining” refers to quantitatively analysing for the amount of a substance present. The term “recover” refers to detecting and/or separating wtGSTO1 from a sample. The sample can be any biological fluid or sample in which GSTO1 is found or expected. The method is preferably an ELISA but any suitable immunoassay method may be used for example a radioimmunoassay, magnetic immunoassay or a lateral flow test. The anti-wtGSTO1 can be attached to a solid support for example a biochip. The wtGSTO1 specific antibodies may be used in the assay on their own or with a secondary generic GSTO1 detection antibody i.e. an antibody which binds both wt and mut GSTO1. An example of the ELISA method comprises wtGSTO1 antibody as the capture antibody and a labelled secondary generic GSTO1 antibody as the detector. The label of the labelled conjugate is a detectable label such as an enzyme, a luminescent substance, a radioactive substance or a mixture thereof. The preferred label is horseradish peroxidase. The detector antibody conjugated to the detectable label described above is an example of a detecting agent for use in the methods of the invention, but any suitable detecting agent can be used. The antibodies of the invention recognise a specific epitope of wtGSTO1; another example of a suitable detecting agent is a monoclonal antibody attached to a detectable label the monoclonal antibody being specific to a different epitope of wtGSTO1. The wtGSTO1 antibody of the invention can be combined with one or more other antibodies that detect different analytes as part of a multi-analyte immunoassay.
[0044] The wtGSTO1 antibody of the current invention can also be used in sample purification methods; for example it may be attached to an immunoaffinity column and used to remove wtGSTO1 from a sample leaving only mutGSTO1. This can be detected and/or determined in a subsequent immunoassay using a polyclonal or monoclonal antibody.
[0045] The invention also describes the use of the antibody of the invention in determining an individual's GSTO1 expression level as an indicator of susceptibility to, diagnosis of, and/or progression of a disease state. The disease state can be any in which GSTO1 has been implicated as a risk indicator or factor including neurodegenerative diseases, such as AD and PD, cerebrovascular diseases, chronic obstructive pulmonary disease and cancer, including hepatocellular carcinoma, cholangiocarcinoma, colorectal cancer, pancreatic cancer, breast cancer and leukaemia. The antibodies described in the invention can also be used in evaluating an individual's resistance to a therapeutic drug.
[0046] Another aspect of the current invention relates to the use of the antibody of the invention in determining wtGSTO1 levels in a sample from a person suspected of having a disease condition, in which the wtGSTO1 concentration differs in the disease state when compared to a control or normal range of expression. The sample may be any biological sample including gel filtrated platelets, whole blood, plasma, serum, urine or saliva.
[0047] Thus, the invention also relates to methods utilising the antibody for (a) evaluating an individual's susceptibility to disease; (b) disease diagnosis and prognosis; (c) evaluating an individual's resistance to a therapeutic drug; and/or (d) in vitro sample purification.
GENERAL METHODS, EXAMPLES AND RESULTS
Production of Human Recombinant (hr) GSTO1 Proteins
[0048] The following proteins were created at Randox Laboratories, hrGSTO1 140A Wild Type (wtGSTO1) comprising a 241 amino acid fragment (1-241) corresponding to the GSTO1 wild type mature protein ( FIG. 3 , SEQ ID NO 3) and hrGSTO1 140D mut (mutGSTO1) comprising a 241 amino acid fragment (1-241) corresponding to the GSTO1 mutant mature protein ( FIG. 3 , SEQ ID NO 4). Each protein was expressed in E. coli with an amino-terminal hexahistidine tag.
Peptide Synthesis
[0049] The peptides used in the preparation of both wild type and mutant GSTO1 immunogens were synthesised using standard techniques by Bachem Ltd (UK). Such techniques are described, for example, in Barany et al (1987) International Journal of Peptide and Protein Research, Vol 30, Issue 6, pp 705-739.
[0000] Conjugation of WTGSTO1 peptide (C-K-E-D-Y-A-G-L-K) (SEQ ID NO 2) to BTG-Maleimide
[0050] The WTGSTO 1 peptide (7.5 μmol) was dissolved in phosphate buffer (20 mM NaP, 0.15M NaCl, pH 7.5), to this solution was added TCEP (1 eq) in 0.5 ml of the same buffer and the mixture was incubated for 2 hrs at room temperature. This solution was added to a solution of BTG-maleimide (100 mg) in 10 ml of PBS (0.1 M NaP, 0.15M NaCl and 1 mM EDTA, pH 7.0) and the mixture was incubated for 4 hrs at RT and overnight at 4° C. The mixture was dialysed against 4 L of PBS pH 7.2, 3 times over a period of 24 hours, and freeze-dried.
[0000] Conjugation of mutGSTO1 Peptide (C-K-E-D-Y-D-G-L-K) (SEQ ID NO 2) to BTG-Maleimide
[0051] The mutGSTO 1 peptide (7.5 μmol) was dissolved in phosphate buffer (20 mM NaP, 0.15M NaCl, pH 7.5) to this solution was added TCEP (1 eq) in 0.5 ml of the same buffer and the mixture was incubated for 2 hrs at room temperature. This solution was added to a solution of BTG-maleimide (100 mg) in 10 ml of PBS (0.1M NaP, 0.15 M NaCl and 1 mM EDTA, pH 7.0) and the mixture was incubated for 4 hrs at RT and overnight at 4° C. The mixture was dialysed against 4 L of PBS pH 7.2, 3 times over a period of 24 hours, and freeze-dried.
Example 1
Development of Monoclonal Antibodies Specific to WTGSTO1
[0052] Pre-immunization blood samples were collected from 16-month-old female Suffolk sheep. On Day 0, each sheep was immunized subcutaneously with 0.1 mg of immunogen, comprising a motif that housed the single amino acid difference between WTGSTO1 and mutGSTO1 conjugated to Bovine thyroglobulin (BTG) (0.25 ml/site over 4 sites). Subsequent boosts, comprising 0.05 mg of the aforementioned immunogen, were administered subcutaneously to each sheep on a monthly basis. Freund's complete adjuvant was used for primary immunizations and Freund's incomplete adjuvant was used for all subsequent injections. Routine bleeds were taken between boosts to monitor the antibody titre, using WTGSTO1 at 1 μg/ml in a direct binding ELISA using polyclonal serum at various dilutions, detected by HRP-conjugated donkey anti-sheep. When the antisera generated by a particular sheep met the required performance criteria, two final peri-nodal boosts were administered, 28 days apart. Four days following the final peri-nodal boost, lymph nodes were harvested from the Left Axillary, Right Axillary, Left Prescapular and Right Prescapular regions. The lymph nodes were first perfused with media and then dissected using scissors and forceps to gently tease apart each piece of lymph node. The scissors and forceps were then used to scrape the remaining lymphocytes from the tissue into the cell suspension. All cells, except those required for the lymph node cell assay (LNCA), were frozen in 90% FBS10% DMSO at a density of 2×10 8. In order to set up the LNCA, lymphocytes from each node location were incubated in a 24 well plate at 1×10 6 cells per well at 5% CO 2 , 37° C. for 7 days. Supernatant was collected from each well for testing as above (polyclonal bleed assessment). The cells from these LNCA plates were then discarded.
[0053] The LNCAs were used to determine whether nodes met standard fusion criteria. Fusion of lymphocytes with a heteromyleoma cell-line was carried out at a ratio of approximately 2:1 by adding 0.5 ml Polyethylene glycol 1500 (PEG) slowly, over 1 minute. PEG was then diluted using serum-free DMEM and the two cell types were allowed to stand for 5 minutes before being plated using 140 ml of 20% DMEM P/S, with x1 hypoxanthine-aminopterin-thymidine (HAT) into 7×96 well plates (200 μl per well). On Day 7, media was replenished on each fusion plate with 20% DMEM P/S, with ×1 HAT and on Day 14, 180 μl/well of supernatant was removed and used to screen Hybridoma culture supernatants by ELISA. The wells were replenished this time with 20% DMEM P/S with xlhypoxanthine-thymidine (HT). The hybridoma culture supernatants were initially screened using the method above (polyclonal bleed assessment). In the follow-up screenings mutGST was used to negatively select hybridoma.
[0054] Positive hybridomas were cloned to produce stable monoclonal hybridomas using 1% methylcellulose at 37° C., 5% CO 2 ; chosen either from positive fusion wells or from established, but unstable cell lines. Three cell lines GT1.1H7.D2, GT7.5B9.B2 and GT7.5B9.F2 were identified as meeting specifications and were cloned in triplicate (with good supporting assay results (FIG. 1 )), before being cloned by limit dilution. Thus, the distinction between the antibodies was achieved by ELISA cross-reactivity studies carried out on cell lines as illustrated in FIG. 1 , which showed the wt specificity of the antibodies.
[0055] Positive cell lines were confirmed as being monoclonal using limit dilution. Single colonies were identified after 7 days and screened for antibody production. Once confirmed as being stable and 100% clonal, the resulting cell-lines were expanded at 37° C., 5% CO 2 for 4 weeks. After 4 weeks, the supernatants were pooled and purified via Protein A purification.
Example 2
Antibody Characterisation
[0056] The antibodies were then conjugated to HRP and characterised to isolate sandwich pairs ( FIG. 2 ) using an existing generic GSTO1 antibody (clone GSm1.7B7.A7.B5.B2.D3.F3.F4.D1 that recognizes a common epitope in WT and mut (available from Randox laboratories CAT no. MAB10069)) on the proprietary protein biochip system Evidence© Investigator (Randox patents EP0994355, EP0988893, EP0874242 and EP1273349). These sandwich pairs were then assessed by testing their ability to bind to native WTGSTO1 protein isolated from gel-filtrated platelets (GFP), prepared by sample lysis in 1×RIPA lysis buffer for 1 hr on ice followed by centrifugation of the samples for 3 min at 13.2 K rpm (16.4 K g). The GFPs were obtained from young healthy controls (J72-J76) and therefore AD patients or AD suspects were not used. Samples J74 and J75 were both found to have the highest WTGSTO1 levels using the WTGSTO1 specific antibodies GT1.1H7.D2.E2.D7.D5.G2.F2 and GT7.5B9.F2.B6.A7.C10.C4 (Table 1). These samples were externally confirmed as being A140A genotypes, (Surgical Research Laboratories, Medical University of Vienna) demonstrating the ability of the WTGSTO1 antibodies in determining the amount and genotype of native GSTO1 in patient samples.
[0000]
TABLE 1
Results from sandwich assays run for patient samples
using either wtGST01 specific GT1.1H7.D2.E2.D7.D5.G2.F2
or GT7.5B9.F2.B6.A7.C10.C4 as capture antibody
and GSTO1 specific GSm1.7B7.A7.B5.B2.D3.F3.F4.D1
as the detection antibody.
MAb—
MAb—
Sam-
GT1.1H7.D2.E2.D7.D5.G2.F2
GT7.5B9.F2.B6.A7.C10.C4
ple
Signal (RLU)
Conc. (ng/ml)
Signal (RLU)
Conc. (ng/ml)
J72
1918
117.96
2403
117.41
J73
3015
184.04
3208
153.13
J74
8957
529.50
10017
456.48
J75
6710
400.54
7599
346.52
J76
1776
109.30
1952
97.10
MAb conc. = 0.08 mg/ml | The invention relates to a novel antibody which binds to wild type (wt) Glutathione S-transferase Omega 1 (wtGSTO1) but not to mutant (mut) GSTO1 and methods and uses based on the antibody. The antibody is based on novel haptens and immunogens. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for checking the integrity of data communications. The invention is particularly relevant in the context of data communications between two communication devices connected via a low bandwidth network.
The invention also relates to a communication device, in particular a smart card, embedding such a method.
2. Description of the Related Art
Communication devices are electronic devices comprising a communication interface. Examples of communication devices include smart cards, USB keys, dongles, Personal Digital Assistants (a.k.a PDAs), mobile phones, personal computers (a.k.a PCs), etc. Typically, such communication devices may be interconnected and communicate with others. For example, a mobile phone may comprise a game console and may allow its user to play games together with multiple other users of similar mobile phones, all mobile phones being connected to a game server or to a plurality of game servers.
Data typically need to be communicated in the form of data packets. A packet is a formatted block of information. A packet generally consists of at least two elements. The first element is a header, which normally marks the beginning of the packet and may contain communication information such as sending and receiving addresses. The second element is a data area (or payload), which contains the information to be carried in the packet. A third element of packet may be a trailer, which marks the end of the packet. The term “packet” is not always used. For example in the context of ISO 7816-3 smart cards the term APDU, for Application Protocol Data Unit, is used instead, at the level of the ISO 7816-3 protocol. However the actual formatting of the data communicated between two communication devices generally corresponds to the above definition of a packet. For example an APDU can be viewed as a packet. The use of packets is often required by the hardware equipment and/or low level protocols forming the communication interface. Packets are extremely useful when a large piece of data exceeding the capacity of the communication interface needs to be transmitted. In such case, data is divided into packets by the sending communication device and reconstructed by the receiving communication device. However, as will be seen more in details below, in the context of the invention, packets are preferably independent one from each other. Although certain types of packets can hold a lot of data (for example IP packets can contain several kilobytes of data), some applications rely primarily on packets containing a small payload. In such applications, each payload is typically independent, in the sense that it forms a logical unit of data, which is self sufficient. In other words, each such payload can be used by the receiving communication device without waiting for other data packets. Indeed, a logical unit of data is typically not broken up in small packets, but rather transmitted in a single packet, unless it is too big in which case it is typically broken up in several maximum size packets. This is due to the fact that there is an overhead for each data packet, therefore one typically tries to use as little data packets as possible. This is also due to the fact that breaking up a logical unit of data in multiple packets requires that the receiving communication devices reconstruct the logical unit of data from several data packets, which can be a tricky task. It should be noted that when a time critical logical unit of data is ready for transmission in the sending communication device, it is often sent immediately in order that the receiving communication device can use it as soon as possible, therefore the sending communication device typically does not wait until more data is available (which would have allowed to fill a bigger packet).
As well known in the art of telecommunications, communications between communication devices are typically prone to errors. Errors are not problematic in certain applications (e.g. a small noise in an analog telephone voice communication) but might have tragic consequences in other applications (e.g. real time transmission of an aircraft altitude to some navigation equipments). Depending on the type of data, errors may have different effects.
With certain types of data, which are referred to as fault resistant data, errors only affect the actual erroneous part of the data. For example, errors in an ASCII text document typically only affect the erroneous characters, and all others characters remain readable. Similarly, errors in uncompressed bitmap image only affect the erroneous pixels, while other pixels remain perfectly visible. Errors in uncompressed digitized sounds only affect the samples which bytes are erroneous, which creates a noise at the level of the sample when the sound is played.
On the other hand, certain data are very sensitive to errors. We refer to such data as fault sensitive data. For example, if a single bit of encrypted data is erroneous, the whole encrypted data is typically complete nonsense once decrypted, and sometimes it can't even be decrypted. If a computer file containing the binary code of a program has even a single bit wrong, it can prevent the program from running or render it unusable. Similarly, errors in certain compressed data (for example a ZIP computer file) typically result in the compressed data being corrupted and impossible to decompress properly, even if the errors only affect a negligible portion of the compressed data. The same is true for many computer binary files.
The error ratio in a data communication is the ratio of the number of incorrect bits (or symbols) to the total number of bits (or symbols) received. It is referred to as the BER, which stands for Binary (or Bit) Error Rate (or Ratio, depending on the authors) and has been subject to intense study by mathematicians, physicists and engineers over the last century. Different techniques have been devised not only to identify errors but also to correct them. Some techniques are generic (i.e. independent of the actual communication channel), for example error correction codes such as Reed Solomon codes, Viterbi codes, Turbo codes and the like, while others are specific to and/or optimized for certain communication channels (e.g. radio relay system in the HF band, satellite links, optical fibers, etc.). However, error correction techniques do not work above a certain BER. Conversely, in some data communications, the reliability is fairly high and the BER is statistically so low that no correction technique is implemented, in particular when the transmitted data are not critical.
Therefore errors may happen from time to time and remain unnoticed in most data communications.
Another known problem with data communications taking place over a network such as the Internet network is the following. Not all packets necessarily travel trough the same path when going from a sending communication device to a receiving communication device. Typically, devices known as routers decide how to route packets, i.e. which path the packet shall follow in order to reach its destination, based on different criteria, such as load balancing, network congestion, etc. Due to the fact that different path can be followed by different packets, the receiving communication device can receive packets in an order different from the order in which they were sent.
It is also possible that some packets are lost (they can be treated as erroneous packets, for example), or on the contrary duplicated (in which case it may be decided, for example, that the first one is taken into account and the subsequent ones are discarded).
Typically, the two main problems mentioned above, namely the packet errors and the wrong order of packets, are addressed by upper layer communication protocols.
For example, since the IP protocol does not deal with errors in the packet payload and with wrong packets order, it is possible to use the TCP protocol over the IP protocol (TCP/IP), which provides a reliable connection by detecting erroneous packets and asking the sending communication device to resend them, and by reordering the received packets. TCP uses a 32-bit sequence number that counts bytes in the data stream. Each TCP packet header contains the starting sequence number of the data in that packet, and the sequence number (called the acknowledgment number) of the last byte received from the remote communication device. With this information, a sliding-window protocol can be implemented.
Unfortunately, such upper layer protocols are typically complex and may consume more bandwidth than available. For example, the TCP header is at least 160 bits long, and may be longer in case optional fields are used. It is a serious impediment in an environment were the payload of the packets is small, e.g. of the same order as a TCP header. If the payload of an average packet is around 20 bytes, then TCP header alone (not considering the additional IP header, plus underlying low level protocols overhead) doubles the bandwidth requirement. Therefore, for many applications TCP is not appropriate. TCP is a complex protocol. In addition, with many TCP implementations, the application cannot access packets coming after a lost packet until the retransmitted copy of the lost packet is received. This causes problems for real-time applications such as streaming multimedia (for example Internet radio), real-time multiplayer games and voice over IP (VoIP) where it is sometimes more useful to get most of the data in a timely fashion than it is to get all of the data without any error.
In the Internet case, simpler protocols are available, for example UDP over IP, however UDP does not provide packet ordering, and does not manage erroneous packets although erroneous packets can be detected thanks to a CRC. UDP is not optimal either in terms of bandwidth consumption.
SUMMARY OF THE INVENTION
It is an object of the invention to propose a method for reliable communication which allows to minimize bandwidth consumption while not requiring a significant increase in the communication device resources consumption. The most significant resources which should be preserved are CPU resources and memory resources. Indeed the processor performance and the available memory might be limited, in particular in resource constrained communication devices such as smart cards.
According to the invention, a preferred method for checking the integrity of a set of data packets received by a receiving communication device from a sending communication device, the data packets of the set being received in unpredictable order, consists in initializing an intermediate integrity check value, and carrying out the following steps.
Each time a data packet of the set is received, the receiving communication device updates the intermediate integrity check value by processing the payload of the received data packet.
The receiving communication device receives an integrity check value from the sending communication device, the integrity check value having been calculated by processing the payloads of all sent data packets of the set.
The integrity check is considered successful if, once all data packets of the set are received, the intermediate integrity check value is equal to the received integrity check value.
This method is particularly advantageous for several reasons. In particular, the method only needs to transmit an integrity check per set rather than transmitting one integrity check per data packet. This reduces the bandwidth consumption accordingly.
The number of packets per set has to be determined depending in particular on the BER of the communication network linking the communication devices. If the BER is very low, it is usually possible to put plenty of data packets per set, while if the BER is quite high, fewer data packets shall be put, since the likelihood of errors in a big set might be such that the set might have to be resent multiple times. In some instances it is possible to identify the specific erroneous data packet of the set, but quite often the whole set needs to be sent again. Another element to consider when deciding how many data packets to include per set is the time necessary to send a whole set. Indeed, if a data packet is corrupted, in general the whole set needs to be resent and this is part of the time elapsed before the correct data packets are available.
The method is also particularly advantageous in the context of applications in which the payload of data packets is small. Indeed, the integrity check value has a fixed size, and transmitting one integrity check per packet (as in state of the art solutions) is therefore particularly detrimental to such applications, as the bandwidth consumption of the integrity check is proportionally a lot more important.
The method is particularly advantageous for applications in which data packets carry primarily small logical units of data. Indeed, in such applications, a data packet can be managed immediately by the receiving communication device, and removed from memory immediately after. If there are L data packets per set, L being high enough, the method of the invention saves a significant amount of memory in the communication device. The amount of saved memory is approximately (L−1) times the size of the payload (compared to state of the art methods sending one, L times bigger, packet), as each payload is typically processed and freed straight away. This memory is typically RAM memory, which is typically very scarce in certain devices. For example, a basic smart card typically contains around 1 kilobyte of RAM. If there are 20 data packets per set, and if each packet has an average 50 bytes payload, this can fill the RAM of such smart card, which would then need to be swapped to EEPROM, while EEPROM is very slow and subject to wear. In a classical method, for the same amount of integrity check values, an L times bigger data packet would have to be received and saved in memory, and then only could the integrity check be computed. In the method of the invention, once the intermediate integrity check has been computed, the data packet can be used by the communication device and freed from memory. If it turns out later on that there was an error in the data packet, it will be resent with the correct data. In this context, the method of the invention is advantageous when data packets carry primarily error resistant data (defined above). Indeed, the communication device will have an estimate of the correct data in a timely fashion, which can be very useful. With certain applications, it is unacceptable to manage the payload of a packet before being sure that the payload integrity is correct. In such applications, it is necessary to record (i.e. to “buffer”) all payloads of the packets which integrity must be correct.
Compared to an alternative method in which data packets of a set would be received, sorted in memory, and processed once the last packet is received the method of the invention would also be advantageous, in that once the last packet has been received, the integrity can be checked faster than in the alternative method since only the last packet would need to be processed. Therefore the time between the reception of the last packet and the validation of the integrity of all packets would be reduced.
According to a preferred embodiment, the method according to the invention is such that the integrity check value is included in the last packet sent by the sending communication device. It should be noted that the last packet sent by the sending communication device is not necessarily the last packet received by the receiving communication device (due for example to above-mentioned routing issues). This technique is advantageous as it avoids sending a separate packet, which would generate some overhead due not only to the packet header but also to the fact that the packet should be distinguished in order that the communication device identifies it as an integrity check value packet (rather than a packet carrying a regular payload). Sending the integrity check value in the last packet requires no overhead. The integrity check value can be appended just after the payload of the last packet. It may be stored in the space dedicated to the payload of the packet, which size would be increased accordingly (e.g. by updating a payload size field).
The invention also relates to a communication device arranged to check the integrity of a set of received data packets with a method as described above. It should be noted that the receiving communication device can be the same device as the sending communication device. For example it is known that a TCP/IP smart card can host web server software, or other types of servers. Two servers inside a single smart card may have to communicate together, and there are some instances in which such communications cannot occur internally in the smart card but have to go through external devices (e.g. external certificate authority servers), in which case the invention may be advantageous.
In particular, the invention relates to smart cards, and more specifically to IP smart cards. The invention is applicable to TCP/IP smart cards, such smart card relying either on TCP or on the invention depending on the context (applications etc.). Many other devices are possible, in particular MMC type cards, SD type cards, USB tokens, or trusted modules designed to secure personal computers (such as TCPA TPM modules), high end microprocessors (such as those used for computers and servers), portable devices (such as PDAs, cellular phones, laptop computers), etc.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and its advantages will be explained more in details in the following specification referring to the appended drawings, in which FIG. 1 shows how three exemplary sets of data packets may be received after traveling from a sending communication device to a receiving communication device, and FIG. 2 represents a preferred method for checking the integrity of a set of received data packets.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates one of the problems addressed by the invention.
The top of the diagram, identified by SND, depicts some sets of packets sent by the sending communication device, while the bottom of the diagram, identified by RCV, depicts the corresponding sets of packets received by the receiving communication device. T represents the time axis. As seen at the top of the diagram, three sets of four data packets are sent consecutively by a sending communication device. Set 1 is sent first, then comes Set 2 and at the end Set 3 . Within each set, packet P 1 is sent first, then goes P 2 , then P 3 and finally P 4 . Each set is represented on a different line for better legibility.
However, due for example to the fact that the network is such that packets traveling between two given points do not necessarily take the same path, the packets are not received in the order that they were sent.
FIG. 1 illustrates two issues. The first issue is linked to the fact that within a given set, the order of the packets can be changed. For example, packet P 2 of Set 1 arrived before packet P 1 of Set 1 . The second issue is linked to the fact that different sets can overlap, in the sense that some packets of a given set may reach the receiving communication device while not all packets of the previous set have been received yet. For example, packets P 1 of Set 2 and P 1 of Set 3 have been received before packet P 4 of Set 1 , which was probably delayed somewhere in the network.
A method according to a preferred embodiment of the invention relies on an integrity check based on a CRC.
Other types of integrity checks are possible, as long as they satisfy the implicit requirements of the method, i.e. as long as they can be adapted to be computed based on data packets which are received in random order. For example, it is possible to use an XOR integrity check, which is also advantageous in that it is faster than CRC and typically does not need specific hardware acceleration. However, basic XOR integrity checks (consisting in dividing data to be checked in blocks and XORing all blocks together) are a bit weak in the sense that two errors at the same bit position in two arbitrarily selected blocks cancel each other and remain unnoticed. A CRC integrity check, although not very strong cryptographically, is much stronger than basic XOR as much better identifies transmission errors, while still reasonably fast. CRC integrity checks therefore represent a good performance*robustness tradeoff.
A CRC (Cyclic Redundancy Code) of length n and dimension k is defined as a set C of polynomials of degree at most n over GF( 2 ), the set C being associated with a polynomial g(x) of degree n−k over GF( 2 ), g(x) being called the generator polynomial, the set C being such that for every polynomial c(x) of degree at most n over GF( 2 ), c(x) belong to C if and only if g(x) divides c(x).
Polynomials c(x) belonging to C are also known as, codewords c(x), and can be expressed in the form c(x)=x n−k m(x)+r(x).
The expression “the CRC of a message m(x)” is commonly used to refer to the polynomial r(x), which is the remainder of the division of x n−k m(x) by g(x).
Numerous versions of CRC exist, depending in particular on the polynomial g(x) which has been chosen and on the length n and dimension k. The following are well known examples of CRCs:
CRC-1 (probably the simplest one, also known as parity bit), CRC-5-CCITT (ITU G.704 standard), CRC-5-USB (used in particular for USB token packets), CRC-7 (used in certain telecom systems), CRC-8-ATM (used in ATM HEC), CRC-8-CCITT (used in 1-Wire bus), CRC-8, CRC-10, CRC-12 (used in telecom systems), CRC-16-Fletcher (used in Adler-32 A & B CRCs), CRC-16-CCITT (X25, V.41, Bluetooth, PPP, IrDA), CRC-16-IBM, CRC-16-BBS (XMODEM protocol), CRC-32-Adler, CRC-32-MPEG2, CRC-32-IEEE 802.3, CRC-32C (Castagnoli), CRC-64-ISO (used in ISO 3309), CRC-64-ECMA-182, CRC-128 (IEEE-ITU Standard, typically superseded by hashes such as MD5 & SHA-1), or CRC-160 (same comments as CRC-128).
Some CRC algorithms differ slightly from the above mathematical definition, in that they set a parameter, commonly referred to as the initial value (IV) of the CRC, to a non-zero value. The IV corresponds to the initial value of the shift register, the shift register being a register used in most implementations of CRC algorithms, as known in the art.
Unless otherwise stated, the IV is equal to zero, since this is required in order to fulfill the mathematical definition stated above. If the IV has been set to a different value, some properties of the CRC are affected. In particular the CRC of zero is no longer equal to zero. This may be useful in certain applications (for example, it may be desired that two files differing only by a number of leading zero bits nonetheless have a different CRC).
However, non-zero IVs are inconvenient in the context of the invention. Indeed, the invention makes use of the mathematical properties of the integrity check in order that it can be computed in random order without affecting the final integrity check value. Therefore, a small adaptation is needed in case a CRC algorithm with non-zero IV is used, as may be the case when a hardware accelerator (or software library) implementing such special CRC is available, and no regular CRC (with IV=0) is available.
According to the invention, in case a CRC with non-zero IV is used, a pre-computation may be performed in order to allow recovering a CRC (with IV=IV 0 ) of a given piece of data M from a function of IV 0 and of the CRC (with IV=IV 1 ) of the same piece of data M. This method works for any IV, in particular IV 0 equal to zero. Let CRC(M, IV 0 ) be the CRC of M with initial value IV 0 .
It can be shown that CRC(M,IV 0 )=CRC(M XOR K 1 , IV 1 ) XOR K 2 . The values of the first and second, constants K 1 and K 2 depend solely on the size of M, on the size of the CRC register, on IV 0 and on IV 1 . Those four parameters typically do not depend on the actual value of data being manipulated which is why we use the term “constant”. XOR operations (especially XOR with constants) being very fast, the method does not affect the performance too much.
To be more accurate, if a message M has a size l (in bits) greater than or equal to t, t being the output size (in bits) of the CRC (which is typically the size of the shift register), then the applicant has found that it is possible to demonstrate that:
CRC( M ,IV 0 )=CRC( M XOR((expand t,l (IV 0 XOR IV 1 ))<< l ( l−t ))IV 1 )
Where:
the expand t,l function transforms a t-bit register into a l-bit register (l being greater than or equal to t) by padding the t-bit register with l−t leading bits equal to zero. In other words, the expand t,l function adds some most significant bits, which do not change the value stored in the register but simply make the register larger: expand t,l (X t-1 , X t-2 , . . . , X 0 )=0 l-1 , 0 l-2 , . . . 0 t , X t-1 , X t-2 , . . . , X 0 . The use of the expand t,l function is implicit and could have been omitted, but is indicated here for improved clarity; the operator << l is the shift left operator for l-bit registers (the length l is specified for improved clarity, although it is implicit), defined as follows. If the binary representation of X is X l-1 , X l-2 . . . X 0 , then the binary representation of X<<l−t is X t-1 , X t-2 , X 0 , 0 l-t-1 , 0 l-t-2 , 0 0 .
If l is smaller than t, then the applicant has found that it is possible to demonstrate that:
CRC( M ,IV 0 )=[CRC( M XOR shrink t,l ( hi t,l (IV 0 XOR IV 1 )),IV 1 )]XOR[ lo t,l (IV 0 XOR IV 1 ))]XOR[(IV 0 XOR IV 1 )]
Where:
the shrink t,l function transforms a t-bit register into a l-bit register (l being smaller than t) by removing the t−l most significant bits. If some of the t−l most significant bits were non-zero, then they are lost: shrink t,l (X t-1 , X t-2 , . . . , X 0 ) is equal to X l-1 . X l-2 , . . . , X 0 . But here the l−t most significant bits are zero by construction; hi t,l (X) is defined for numbers X represented as a t-bit register. hi t,l (X) is equal to the number which binary representation consists of the l most significant bits of X. In other words, if the binary representation of X is X t-1 , X t-2 . . . X 0 where each X i is a bit, hi t,l (X) is equal to the number which binary representation in a t-bit register is 0 t-l-1 , 0 t-l-2 , . . . 0 l , X l-1 , X l-2 , . . . X t-l ; lo t,l (X) is defined for numbers X represented as a t-bit register. lo t,l (X) is equal to the number which binary representation consists of the l least significant bits of X. In other words, if the binary representation of X is X t-1 , X t-2 . . . X 0 where each X i is a bit, lo t,l (X) is equal to the number which binary representation in a t-bit register is 0 t-1 , 0 t-2 , . . . 0 l , X l-1 , X l-2 , . . . X 0 ).
Possible uses of the above formulae are explained below:
In order for a receiving communication device to compute the CRC of M with IV=IV 0 (in our case IV 0 =0) while the receiving communication device only comprises hardware or software computing the CRC of M with IV=IV 1 , other than by re-implementing a CRC method, one may XOR M with a first constant K 1 , and use the device or software to compute the CRC on M XOR K 1 . If the second formula above is needed (CRC computed on data shorter than the CRC register), an additional step has to be performed, during which the result of the CRC provided by the device or software is XORed with a second constant K 2 (in the first formula K 2 =0).
In preferred embodiments, most CRCs are calculated on t-bit data (because most CRCs are computed on the output of a previous CRC), therefore l=t and the first formula is used. When l=t, the formula is simplified. One simply has to XOR the data with IV 0 XOR IV 1 before calling the CRC. In fact, since IV 0 =0 in our case, one simply has to XOR the data with IV 1 . In preferred embodiments, the payload is bigger than the size t of the CRC register, therefore in rare instances where the CRC is performed on data which length is not t, the CRC is typically performed on data which length is l, le being greater than t. Consequently the first formula (l>=t) is used more frequently than the second one.
In order to check the integrity of a set of data packets payloads which integrity check value has been computed (and sent) by the sending communication using a CRC with IV=IV 1 , wherein IV 1 is not zero, the receiving communication device can use the following method based on the above formulae.
The received integrity check value (denoted R_CRC) is equal to CRC(M,IV 1 ). The receiving communication device cannot use CRC(M,IV 1 ) in the context of the invention because such CRC (with non zero IV) does not satisfy the mathematical properties needed for the invention. But the receiving communication device can use the above formula: CRC(M, IV 1 )=CRC(M XOR K 1 , IV 0 ) XOR K 2 (the names IV 1 and IV 0 have been swapped for legibility, which does not affect the formula as the names are purely conventional).
This formula can also be written:
CRC( M XOR K 1 ,IV 0 )=CRC( M ,IV 1 )XOR K 2 =R _CRC XOR K 2
R_CRC XOR K 2 can be easily computed by the receiving communication device. Instead of verifying the integrity of M, the receiving communication device now has to verify the integrity of M XOR K 1 . At first sight, this may seem a strong constraint, since it could imply that the whole set of data packets payloads has to be buffered in order to be XORed with K 1 before being processed. This would be very inconvenient if M were big. However, as seen in the above first formula (applicable to this situation), K 1 affects at most t bits of the message M, and t is typically small. in rare instances where t is bigger than the size of the payload of a single data packet, the receiving communication device simply needs to buffer those data packets which are affected by K 1 (i.e. very, few packets).
Although it has been shown that it is possible to handle a R_CRC computed with a non-zero IV, it is preferred to avoid such situations by using zero as an IV in the sending communication device.
Depending on the implementation, the polynomial g(x) reducing the expression in the CRC computation may be used in reverse representation (a.k.a little-endian representation). In this case, the final XOR (IV 0 XOR IV 1 ) is to be performed with reverse representation of IV 0 and IV 1 .
For example, using an hexadecimal representation, let us consider M=0x5D and the CRC-16-CCITT with polynomial in normal representation (a.k.a big-endian representation) 0x1021. Let IV 0 =0x064C, IV 1 =0x1DCD and IV 2 =IV 0 XOR IV 1 =0x1B81.
CRC-16-CCITT(M, IV 0 )=0xA1D2.
However, if one is unable to compute CRC-16-CCITT with an IV equal to IV 0 , but only able to compute it with an IV equal to IV 1 , then:
CRC
-
16
-
CCITT
(
M
,
IV
0
)
=
[
CRC
-
16
-
CCITT
(
(
0
×
5
D
XOR
0
×
1
B
)
,
IV
1
)
]
XOR
[
0
×
1
B
81
]
XOR
[
0
×
0081
]
=
0
×
A
1
D
2
In the rest of the description, it is assumed that the CRC has an initial value IV equal to zero since it has good mathematical properties. In particular padding the message with leading zero bits does not change the value of the CRC. This typically makes it useless to mention the expand function inside parameters of such CRC, even for clarity. It is possible to adapt CRCs with non-zero IV to CRC with IV equal to zero with the above technique. In the rest of the description, CRC(M) stands for the CRC of M computed with an initial value IV equal to zero.
By studying the mathematical properties of CRC, the applicant has designed a preferred method for computing a CRC in the context of the invention. The notations used above for mathematically defining a CRC are no longer used in the rest of the document (in particular, parameters n and k will have different meanings as explained below).
The method is based on the following formula, devised by the applicant; which is true for any CRC as mathematically defined above:
CRC(set)=XOR i=1 . . . L (CRC( hi t,si (int_crc_pl i ))XOR((lo t,t-si (int_crc_pl i ))<< si ))
where:
set is a set of ordered data packets which CRC has to be computed (only the payloads pl i of the data packets are processed, other elements of the data packet are not taken into account in the computation of the CRC); int_crc_pl i is equal to CRC 1+floor((L−i)*k/t) (pl i ), wherein floor(x) denotes the greatest integer lower than or equal to x, wherein CRC 1 (X)=CRC(X), and wherein CRCP p (X)=CRC(CRC p−1 (X)) for p>1; pl i denotes the payload of the i th sent data packet (pl 1 is the payload of the first data packet that was sent, pl L is the payload of the last data packet that was sent), the size of each payload pl i being constant and equal to k. The size of the output of the CRC is denoted t; si is equal to (L−i)*k mod t, i.e. the remainder of the division of (L−i)*k by t; hi t,z (X) is defined for numbers X represented as at bit register. hi t,z (X) is equal to the number consisting of the z most significant bits of X. In other words, if the binary representation of X is X t-1 , X t-2 . . . X 0 where each X i is a bit, hi t,z (X) is equal to the number which binary representation in a t bit register is 0 t-z-1 , 0 t-z-2 , . . . 0 0 , X t-1 , X t-2 , . . . X t-z ; lo t,z (X) is defined for numbers X represented as at bit register. lo t,z (X) is equal to the number consisting of the z least significant bits of X. In other words, if the binary representation of X is X t-1 , X t-2 . . . X 0 where each X i is a bit, lo t,z (X) is equal to the number which binary representation in at bit register is 0 t-1 , 0 t-2 , . . . 0 z , X z-1 , X z-2 , . . . X 0 ; the operator is the shift left operator. In other words, if the binary representation of X is X t-1 , X t-2 . . . X 0 , then the binary representation of X<<z is X t-1-z , X t-2-z , . . . X 0 , 0 z-1 , 0 z-2 , . . . 0 0
A pseudo code implementing a preferred method based on the above formula is represented on FIG. 2 .
According to this method, the payloads of all data packets of the set are of equal size k. The integrity check value of the last sent data packet is not counted in the payload of the last sent data packet.
L denotes the number of data packets, in the set. t denotes the size of the output of the CRC in bits. floor(x) denotes the greatest integer lower than or equal to x. The intermediate integrity check value is stored in a variable r initialized with 0. The integrity check comprises:
a. receiving a data packet and extracting its payload (pl) and index (i), wherein the index (i) is the order of the data packet in the set as sent, wherein index 1 stands for the first sent data packet and index L stands for the last sent data packet,
b. recursively calculating the CRC of the payload (pl) i times, the final result being denoted int_crc_pl. int_crc_pl is equal to CRC i (pl), wherein CRC 1 (pl)=CRC(pl) and CRC j (pl)=CRC(CRC j−1 (pl)) for j between 2 and i.
c. calculating the CRC of the number consisting of the si most significant bits of int_crc_pl, wherein si is equal to (L−i)*k mod t,
d. shifting left by si bits the number consisting of the t−si least significant bits of int_crc_pl,
e. XORing the result of steps c and d with r, and storing the result in r, and repeating steps a to e until all data packets of the set have been received.
It should be noted that the order of steps c and d does not matter, and it is equivalent to do first d and then c. The XOR operation is associative and commutative therefore the order of the XORs in step e doesn't matter. It should also be noted that if k is a multiple of t, steps c and d are significantly simplified since si=0. In such case, step c and d can be omitted, and step e consists in XORing int_crc_pl with r and storing the result in r.
The data packets can be for example IP packets, or SMS messages (which according to ETSI 03.40 standard are not necessarily protected by an integrity check).
A step by step description of the implementation depicted on FIG. 2 follows.
The depicted implementation omits the initialization of the variables for the sake of simplicity, and focuses on the loop executed when a data packet is received.
The first instruction, pac=receive_packet( ), means that a packet is received and stored in a variable denoted pac. The received packet typically triggers an interruption which wakes up the receive_packet function, but other solutions are possible (e.g. regular polling in order to check whether a packet is received).
The following instruction, s=read_set_id(pac) means that the identifier of the set to which the packet belongs is extracted from the packet.
Next, the instruction nb_received_packets[s]=nb_received_packets[s]+1 means that a variable nb_received_packets, which is a vector, and which contains the number of received packets for each set currently being received, is incremented in order to reflect the fact that a new packet was just received for set s. Each element of the vector is associated with one of the sets for which at least one data packet has been received, but for which not all data packets have been received. The size of the vector can be determined according to the type of communication network. For example, if in a given network no more than 5 sets can overlap, it is sufficient to allocate 5 elements in the vector. N.B. the 5 overlapping sets are not necessarily contiguous (there might be non-overlapping sets in between). For example, a sending communication device can send 10 consecutive sets {Set 1 } . . . {Set 10 }. The receiving communication device may receive them in the following order: {Set 1 }, {Set 2 }, {beginning of Set 3 }, {Set 4 }, {Set 5 }, {Set 6 }, {end of Set 3 }, {Set 7 }, {Set 8 }, {Set 9 }, {Set 10 }. In this example, although the overlap spans four sets (Set 3 to Set 6 ), only two sets overlap at any point in time, therefore only two elements in the vector are needed. To be more specific, Set 3 start overlapping with Set 4 , but as soon as Set 4 has been completely processed Set 3 does not overlap with Set 4 anymore but starts overlapping with Set 5 , and as soon as Set 5 has been completely processed, Set 3 does not overlap with Set 5 anymore but starts overlapping with Set 6 .
Next, the instruction i=read_packet_index(pac) means that the packet index is extracted from the packet. The packet index is the order of the packet in the set s.
In preferred embodiments, the packet is an IP packet, and both the packet index i and the set identifier s are stored in the Identification field of the IP packet header. This is very advantageous for several reasons. In particular, thanks to the Identification field, no extra bandwidth is needed since the IP header would have been sent anyway (and would have carried an empty Identification field). This is to be compared with other protocols such as for example the TCP protocol over IP, in which a special field has to be used in the TCP header in order to store a 32 bit sequence number already described above, and which is added to the IP header. The sequence number has a role similar to the set identifier s and packet index i, but imposes a 32 bit overhead in each packet. In addition, the fact that s and i are stored in the IP header means that they are protected by the IP header checksum, and if there is a transmission error on i and/or s, the IP packet will be resent without requiring the whole set of IP packets being processed and then totally resent due to the error. The identification field is only 16 bits long but this is amply sufficient in preferred embodiments. It can contain for example a 6 bit set identifier and a 10 bit packet index, which would allow to manage up to 64 different set identifiers and 1024 packets per set. In typical embodiments of the invention, it is very unlikely that a set is delayed so long that it arrives later than 63 other sets sent after this set. But it is also possible to use different values depending on the particular context, for example the method may be able to manage 128 sets (7 bits) of 512 packets (9 bits), or any other combination (b bits for s and 16-b bits for i). According to the IP protocol, the identification field is normally an identifying value assigned by the sender to aid in assembling the fragments of a datagram. The identification field is rarely used in practice, since some experts state that less than 0.25% of IP packets on the Internet are fragmented. In the context of the invention, packets are typically small enough to never be fragmented, therefore the use of the identification field is not problematic. With this embodiment, the bandwidth overhead of the method is t bytes per set of data packets, where t is the size of the CRC. For example, if there are 256 data packets per set, and if CRC16 is used, the overhead is equal to 16 bits per set. With TCP, the overhead would be 256*(160+options) bits, since the TCP header takes at least 160 bits (more if options are used). Therefore the overhead in such configuration is at least 2560 times smaller with the invention than with TCP/IP. This is very significant especially for small data packets, which are very sensitive to the overhead.
Next, the instruction if i=L, checksum[s]=extract_set_integrity_check(pac), means that if the packet which has just been received is the last sent packet of the set, the integrity check is contained in this packet and should be retrieved. The integrity check is typically stored in the payload of the data packet, unless the header or trailer contains an unused field which could contain it. In preferred embodiments, the integrity check is stored in the payload of the last IP packet of the set. However, the integrity check is not considered as part of the payload by the method, although for the network it is part of the payload. For example, if each data packet has a payload of 20 bytes, then the last data packet would have a payload of 22 bytes (if CRC16 is used), including 20 bytes of “real” payload and 16 bits of integrity check value. The integrity check value is stored in a vector checksum which structure is similar to the above discussed structure of nb_received_packets.
Next, the instruction pl=extract_payload (pac) extracts the payload of the packet (not including the integrity check if this is the last packet). The extraction may simply consist in providing a pointer to the payload.
Next, the instruction manage_payload(pl) lets the communication use the payload as intended. It should be noted that the payload is managed just after the packet has been received (almost no delay). Indeed, the instructions between the receive_packet and the manage_payload instructions are simple read/write operations requiring almost no time to execute. If the data is fault resistant (as defined above), it can be managed as if its integrity had been checked, although there might be some minor side effects as explained above. If the data is fault sensitive, it can also be managed, however this may lead to a completely erroneous result until the correct data packet is received and processed. This is not necessarily problematic. For example, in a distributed computing application such as online gaming, in which hundreds of users may be connected to a game server in parallel and play in a common environment, the server may send the elements of the scenery (e.g. in a multi-player flight simulator game). For example, it can send the identifier and position of moving objects such as cars (on roads) and boats (on a lake), which each game console (e.g. a cellular phone game console) interprets and displays accordingly. Those parameters are error sensitive, in the sense that if there is even a single bit error in the identifier, the object may be completely wrong (a boat can be replaced by a cow or a harvester), and if some of the most significant bits of the position are wrong, the object will be displayed in a totally wrong position. However, the object will be quickly replaced by the right object, and the display of the wrong object doesn't have bad consequences in general (except if a boat ends up in the middle of a landing strip while the player is trying to land, or similar unlikely events).
Optionally, manage_payload(pl) may comprise additional parameters, such as manage_payload(pl, i, s), which give information on the position of the payload in the set and may let the application sort certain packets (e.g. if certain packets must be managed before certain other packets), or identify certain packets. For example, it may be that the structure of the set of packets is always the same and that the contents of a data packet can be inferred from its index, at least for certain indexes.
Optionally, the data packet payload can contain a flag indicating that it contains critical data which shouldn't be managed until its integrity check is verified, or which can be managed by anticipation but should have some elements kept in memory in order to be able to “roll back” in case the payload appears to be wrong, or is susceptible to be wrong (since the integrity check is performed on the whole set, the actual payload might be correct, but there is not necessarily a way to check it so it may have to be resent—by default all data packets of the set are resent). The “roll back” consists in coming back to the state before the payload was managed. In this case, the manage_payload function may put the address of the payload (and/or of other relevant information) in a stack (one stack per set). When the set integrity is checked, it is then necessary to process all stacked payloads.
Next, the instruction int_crc_pl=CRC(pl) computes the CRC of the payload, and the instruction free(pl) frees the payload from memory (optionally, it only frees the payload if it contains no critical data, i.e. if the critical data flag is no set).
Next, the loop for p=1 to floor ((L−i)*k/t), int_crc_pl=CRC(int_crc_pl) calculates the CRC of int_crc_pl x times, wherein x=floor ((L−i)*k/t) which produces the result of the recursive calculation described herein above in step b for calculating CRC i (pl).
Next, the instruction si=(L−i)*k mod t computes the si parameter.
Next, the instruction r[s]=r[s] XOR CRC (hi t,si (int_crc_pl)) XOR ((lo t,t-si (int_crc_pl))<<si) computes the intermediate integrity check value (which corresponds to steps c, d and e, in a single instruction).
Next, the instruction if nb_received_packets[s]=L checks whether all packets of the set corresponding to the last received packet have been received. If all packets have been received, the instruction if r[s]=checksum[s] checks the integrity of the set by comparing the received integrity check value checksum[s] with the computed integrity check value (equal to the last intermediate integrity check value r[s]). If the integrity is correct, the instruction validate_set(s) is called. This instruction can release all memory which was allocated to the set, such as elements with index s of the vectors r, checksum, nb_received_packets, etc. and make them available for a future received set. This instruction can also manage the payloads which were marked as critical and free them. If the integrity is not correct, the instruction else, request_resend(s) is called. This instruction can request the whole set to be resent, and in case some critical payloads were stacked, it can remove them from the stack without managing them (or roll back those which were managed by anticipation thanks to the stacked information). Irrespective of whether the integrity of the set is correct or not, the intermediate integrity check value r[s] is reset to zero with the instruction r[s]=0 in order for the next set which index will be s to be processed properly.
The method can then restart from the beginning, by waiting for the next packet with the instruction, pac=receive_packet( ).
The calculation of the CRC of a set of L data packets according to the above method is approximately L/2 times slower than the calculation of L CRCs of L data packets according to state of the art methods. However, given that a CRC is a fast operation, and it is even faster when it is hardware accelerated, the method does not have a significant impact on the performance
This method can be improved in order to be adapted to a multitask environment. Indeed, a CRC engine (whether a software CRC engine or a hardware CRC engine when a CRC hardware accelerator is available), is not necessarily multitask. Typically, computing the CRC of data which is longer than the CRC register requires several accesses to the CRC engine, and each time the CRC engine is called, the state of the engine should be memorized in order that the subsequent call is properly handled. In a multi task environment, different routines might be willing to compute a CRC in parallel, in which case the results of the CRC are corrupted. Some CRC engines are designed to backup their contents for each calling application and restore them when the application calls them again, which solves the issue. However, not all hardware CRC engines allow the initialization of their register, therefore it is not always possible to have them support multitask environments.
For example, in some microcontrollers (e.g. SATURN chip of HP 48 SX calculator), a CRC engine is connected to the data bus of the processor, and in order to compute the CRC of some data, one simply has to set a pointer to the beginning of the memory containing the data, and read the data sequentially. Obviously, if there is an interrupt and if some interrupt routine starts reading data in memory (which any routine does), the data bus is fed with other data which corrupts the initial CRC computation.
With the above method, each call to the CRC module only involves data contained in one CRC register, and is independent of other CRC calls, with one potential exception. The potential exception is the instruction int_crc_pl=CRC(pl). Indeed the payload pl has a length of k bits, which is typically greater than the size t of the CRC register. t is normally equal to the size of the output of the CRC. The improvement consists either in using a block size k equal to t, in which case no change is needed, or in replacing the above instruction by:
int_crc_pl=0
for p=floor((k−1)/t) downto 0
int_crc_pl=CRC(int_crc_pl XOR lo k,t (pl(p*t)))
where the operator is the shift right operator. In other words, if the binary representation of X is X k-1 , X k-2 . . . X 0 , then the binary representation of X>>z is 0 z-1 , 0 z-2 , . . . 0 0 , X k-1 , X k-2 , . . . X z . In preferred embodiments, the method is implemented in a communication device which has a CPU. Obviously, if k and t are properly chosen, in particular if they are multiples of the size of the smallest element addressable by the CPU, i.e. typically a multiple of 8 bits in particular on simple CPUs, the use of the right shift operator can be replaced by a direct read operation in memory (the CPU can directly access the relevant sub block instead of computing shift operations on the whole block).
The performance (in terms of speed of execution) is optimal when k and t are powers of 2. t is typically equal to 2 4 or 2 5 .
With such k and t, remainders and integer divisions or multiplications are simplified by involving simple AND masks and shifts. With many cryptographic devices, it is advantageous to pass the t-bit data (which CRC computation is desired) to the CRC module without indirection (by directly passing the value). This is particularly efficient when the registers of the CPU are t-bit wide or can contain t-bit numbers. | The invention relates to a method for checking the integrity of a set of data packets received by a receiving communication device from a sending communication device, the data packets of the set being received in unpredictable order. The invention also relates to a communication device implementing a method according to the invention, in particular to a smart card. | 7 |
RELATED APPLICATIONS
[0001] This application claims priority benefit of U.S. Provisional Application Ser. No. 61/915,669 filed 13 Dec. 2013; the contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention in general relates to remote controlled vehicles, and in particular to a vehicle that combines autonomous vehicle control, with independent azimuth and elevation control for a position sensitive application payload
BACKGROUND OF THE INVENTION
[0003] The Global Positioning System (GPS) is based on the fixed location base stations and the measurement of time-of-flight of accurately synchronized station signature transmissions. The base stations for the GPS are satellites and require atomic clocks for synchronization.
[0004] GPS has several draw backs including relatively weak signals that do not penetrate heavy ground cover and/or man made structures. Furthermore, the weak signals require a sensitive receiver. GPS also utilizes a single or narrow band of frequencies that are relatively easy to block or otherwise jam, and can easily reflect to surfaces, resulting in multi-path errors. The accuracy of the GPS system relies heavily on the use of atomic clocks, which are expensive to make and operate.
[0005] U.S. Pat. No. 7,403,783 entitled “Navigation System,” herein incorporated in its entirety by reference, improves the responsiveness and robustness of location tracking provided by GPS triangulation, by determining the location of a target unit (TU) in terrestrial ad hoc, and mobile networks. The method disclosed in U.S. Pat. No. 7,403,783 includes initializing a network of at least three base stations (BS) to determine their relative location to each other in a coordinate system. The target then measures the time of difference arrival of at least one signal from each of three base stations. From the time difference of arrival of signals from the base stations, the location of the target on the coordinate system can be calculated directly. Furthermore, the use of high frequency ultra-wide bandwidth (UWB) wireless signals provide for a more robust location measurement that penetrates through objects including buildings, ground cover, weather elements, etc., more readily than other narrower bandwidth signals such as the GPS. This makes UWB advantageous for non-line-of-sights measurements, and less susceptible to multipath and canopy problems.
[0006] Controller area network (CAN) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer. CAN bus is a message-based protocol, designed specifically for automotive applications but now also used in other areas such as industrial automation and medical equipment.
[0007] A critical component to autonomously guide a vehicle that requires evenness or a steady position for a payload to operate properly is to create a path that the vehicle can traverse. When a human-operated vehicle moves near unevenness (bump or hole) in the path, the operator may control the vehicle around that area, to maintain a smooth ride for the vehicle platform. While, a lot of work has been done on path-planning, obstacle avoidance, and terrain recognition, these technologies are expensive and not always robust.
[0008] Thus, there exists a need for an integrated system that combines autonomous vehicle control, with independent azimuth and elevation control for an application payload that is reliable and cost effective.
SUMMARY OF THE INVENTION
[0009] An autonomous self-leveling vehicle is provided that includes a controller and an RF antenna. A platform is attached to articulating legs with joint actuators for leveling or maintaining said platform at a defined angle. A set of wheels are powered by wheel actuators mounted to the distal ends of the articulating legs to provide self-leveling.
[0010] A system for a self-leveling vehicle includes at least three or more base stations. A vehicle with a platform having articulating legs with joint actuators for leveling or maintaining the platform at a defined angle is provided above and operates with an RF antenna mounted to the vehicle and a controller with a tracking module in the range of the base stations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A is a side view of an embodiment of the inventive autonomous self-leveling vehicle;
[0012] FIG. 1B . is a top view of the inventive autonomous self-leveling vehicle of FIG. 1 ;
[0013] FIG. 2 is a schematic diagram of the electronic components that form a tilt-compensated (TC) compass to determine vehicle position and orientation; and
[0014] FIG. 3 is a schematic representation of a location measurement device illustrating roll, pitch and yaw measurement determined from 3D accelerometers and 3D magnetic sensors.
DETAILED DESCRIPTION OF THE INVENTION
[0015] An inventive autonomous self-leveling vehicle provides a drive-by-wire vehicle with an adjusting self-leveling platform. The drive-by-wire system used in embodiments of the autonomous self-leveling vehicle use joint actuators to control the attitude of the vehicle platform via articulated legs attached to the platform and wheels, and wheel drive actuators to perform steering and driving for the vehicle, to provide control and movement in an operating space. In an embodiment, a communication interface for the drive-by-wire components may be controller area network (CAN), or other available controller based communication technologies. Embodiments of the autonomous self-leveling vehicle have a vehicle controller that communicates with an operator, and includes a position tracking system. The position tracking system could be standard GPS or the tracking system described in the aforementioned U.S. Pat. No. 7,403,783, or other radio frequency (RF) based position tracking systems. The vehicle controller communicates with the drive-by-wire vehicle actuators to control the vehicle motion and attitude during autonomous operation. Embodiments of the inventive vehicle have an autonomous navigation module that includes antenna, 3D accelerometer, 3D compass, 3D gyroscopic sensors, and a microcontroller with software. A non-limiting application of an embodiment of an autonomous self-leveling vehicle is in the entertainment industry, for maneuvering still and movie cameras during scenes or sequences.
[0016] In embodiments of the inventive vehicle, the leveling a platform is oriented relative to earth's plane of gravity. A non-limiting example of a self-leveling method is described in U.S. Pat. No. 7,908,041 entitled “Self-Leveling Laser Horizon for Navigation Guidance,” herein incorporated in its entirety by reference. Embodiments of the invention combine autonomous vehicle control, with independent azimuth and elevation control for the application payload.
[0017] In embodiments of the vehicle, integration of the operational system (platform leveling method with the autonomous guidance) is accomplished by first implementing the vehicle guidance software and the platform leveling software in the same architecture, and sharing inertial sensor inputs. Furthermore, the system may require extra user input, to understand the objective of the operating scenario or picture or movie shoot. For example, path planning and programming should include combined X/Y location, and orientations, so the autonomous vehicle controller “knows” how the user would like the payload to move though space or to shoot the scene. Furthermore, integration of the leveling algorithms with the autonomous vehicle control system, is of benefit since the leveling algorithms can be programmed to anticipate vehicle motion, and in particular when turning the vehicle on an inclined surface, where anticipation helps to maintain leveling performance of the platform by predicting the simultaneous roll/pitch motion during an inclined yaw maneuver.
[0018] Furthermore through integration of the platform leveling method with the autonomous guidance, the autonomous control system of the vehicle controller can be programmed to maneuver the vehicle along a desired path in a way that benefits the platform leveling system. For example, when driving on an incline, the controller may have the liberty to drive forward or reverse (and even more freedom of maneuverability with omni-directional vehicles) in order to orientate the vehicle so to optimize leveling of the chassis.
[0019] In an embodiment, a separate azimuth/elevation drive can be attached to the vehicle chassis to provide independent camera motion relative to the platform. However, if the camera motion system has mechanical limitations, these could be compensated by the vehicle autonomous control and leveling. For example the chassis leveling system could maintain the platform at a constant desired non-zero angle, to provide additional elevation angle.
[0020] FIGS. 1A and 1B illustrate an embodiment of a self-leveling autonomous vehicle 10 being used as a motion platform in the entertainment industry for automated still and motion camera control. The vehicle 10 has a platform 12 for mounting a camera 24 or other imaging device. The vehicle 10 is controlled with autonomous vehicle controller 12 via communication link antenna 16 . Articulating legs 18 adjust up and down with joint actuators 20 to maintain the platform 12 in level state or at a defined angle despite surface conditions encountered as the vehicle 10 moves with wheel actuators 22 . The autonomous vehicle controller 12 communicates with joint actuators 20 and wheel actuators 22 via CAN bus or other communication protocols.
[0021] By actively controlling the roll and pitch of the vehicle chassis, the wheels of the vehicle may be allowed to go through holes and bumps, and up or down a curb, while still maintaining the payload camera in a steady even state or orientation. Existing remote camera platforms, without leveling technology typically operate on a rail or path that is smooth in order to provide an even ride for the camera payload. However, platforms limited to rails or paths will often result in limitations for the artistic input, since the vehicle platform will be limited to a subset of the terrain that is served by the rail or path. With embodiments of the self-leveling vehicle, many of these limitations are eliminated.
[0022] The roll, pitch, and heading for the vehicle 10 are measured with the 3D accelerometer, and 3D compass (3D magnetic sensors), configured as a tilt-compensated (TC) compass. A tilt compensated Compass is a device that can measure an object's horizontal orientation (i.e., direction within Earth's magnetic field) for any arbitrary orientation of that object in the vertical field (i.e., roll and pitch). In other words, for any forward or sideways rotation, a TC device will calculate the heading relative to the North Pole (An in-depth discussion on acquiring roll and pitch angles relative to gravity, and heading angle relative to earth magnetics' field, see [AN3192 by STMicroelectronics]. In instances where the reference frame of the RF position tracking system is orientated with a known orientation in the global coordinate system, then the heading from the TC compass can be related to the orientation within the RF reference frame. In general, the RF position tracking system may not be related to the global coordinate system, but to an ad-hoc system of locating base stations, and a calibration procedure takes place to correlate the TC compass measurement to the orientation within the reference frame of the RF positioning system.
[0023] FIG. 2 is a schematic diagram of the electronic components that form a tilt-compensated (TC) compass 30 for use with the vehicle 10 . The TC compass 30 operates by taking the output (analog) readings of a 3-axis accelerometer 32 and the output (analog) readings of a 3-axis magnetic sensor 34 and applying the readings to an analog to digital (A/D) converter 36 , which then provides a digital data stream to a microcontroller 38 configured with software to calculate parameters including pitch, roll, and heading.
[0024] FIG. 3 is a schematic representation of a location measurement device 40 illustrating roll, pitch and yaw measurement determined from the TC compass 30 in Cartesian coordinates. TC compass 30 may be implemented as an integrated circuit (IC) such as an LSM303DLH available from STMicroelectronics.
[0025] The orientation information of the location measurement device 40 can now be used to enhance the accuracy of the RF position tracking system of the vehicle controller 14 , depending on the operating scenario. With the knowledge of the current orientation and position, and with knowledge of the beacon locations for tracking, the system will be able to determine the direction of each of the range measurements to each of the beacons, and add a level of confidence to each of the measurements, depending on the reasonable estimation of the relative location of the vehicle 10 . In an embodiment the base stations or beacons may be part of a mobile network. In an embodiment the base stations or beacons are formed in an ad hoc network communicating via high frequency ultra-wide bandwidth (UWB) wireless signals.
[0026] The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention. | An autonomous self-leveling vehicle is provided that includes a controller and an RF antenna. A platform is attached to articulating legs with joint actuators for leveling or maintaining said platform at a defined angle. A set of wheels are powered by wheel actuators mounted to the distal ends of the articulating legs to provide self-leveling. A system for a self-leveling vehicle includes at least three or more base stations. A vehicle with a platform having articulating legs with joint actuators for leveling or maintaining the platform at a defined angle is provided above and operates with an RF antenna mounted to the vehicle and a controller with a tracking module in the range of the base stations. | 1 |
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 12/208,182 entitled “ARTICULATING CABLE CHAIN ASSEMBLY”, and filed Sep. 10, 2008 by ALAN T. PFEIFER. The aforementioned application is assigned to an entity common hereto, and the entirety of the aforementioned application is incorporated herein by reference for all that it discloses and teaches.
BACKGROUND OF THE INVENTION
Customer replaceable units (CRUs) have provided a convenient and simple way of replacing appliances such as disk drives in servers, RAID devices, etc. Drives, such as hot spares, mirror drives in a RAID unit, or any type of replacement drive can be easily removed or replaced using CRU devices. Disk drives can be plugged and unplugged from the chassis of RAID units, servers, computers, etc. with cables having connectors that connect to the back of the unit. Hence, the CRUs are a practical and convenient way to replace appliances, such as disk drives, that are utilized in the computer and electronics industry.
SUMMARY OF THE INVENTION
An embodiment of the present cable chain return system may include a method of returning a cable chain from an extended position to a retained position, the method comprising: providing a cable chain made from a plurality of links having a limited arc of rotation, the links periodically reversed on the articulated cable chain so that the cable chain forms a plurality of folding curves in sequentially opposite directions along the cable chain when the cable chain is in a retained position, the cable chain defining: a proximal end attached to the chassis, a distal end oppositely disposed from the proximal end and attached to a customer replaceable unit; a biased section adjoining the proximal end; and, placing a spring adjacent to the cable chain proximal end that engages the cable chain biased section and the chassis so that the spring biases the cable chain biased section towards the chassis to initiate forming of the plurality of folding curves when the customer replaceable unit is moved from the extended position to the retained position.
An embodiment of the present cable chain return system may include a cable chain return system connected to a customer replaceable unit and a chassis, the cable chain return system comprising: a cable chain made from a plurality of links that have a limited arc of rotation, the links periodically reversed on the cable chain so that the cable chain forms a plurality of folding curves in sequentially opposite directions along the cable chain when the a cable chain is in a retained position, the cable chain defining: a proximal end attached to the chassis, a distal end oppositely disposed from the proximal end and attached to the customer replaceable unit, a biased section adjoining the proximal end; and, a spring attached to the chassis adjacent to the cable chain proximal end adjoining the cable chain biased section, the spring disposed on the chassis to bias the cable chain biased section towards the chassis for initiating the plurality of folding curves when the cable chain moves from an extended position to the retained position.
An embodiment of the present cable chain return system may include a method of installing a cable chain return system for a customer replaceable unit in a chassis that extends from the chassis, the method comprising: providing a cable chain made from a plurality of links that have a limited arc of rotation, the links periodically reversed on the articulated cable chain so that the cable chain forms a plurality of folding curves in sequentially opposite directions along the cable chain when the cable chain is in a retained position, the cable chain defining a proximal end and an oppositely disposed distal end; providing a spring comprising: a first coil section and a second coil section integrally formed with the first coil section separated by a spring separation distance from the first coil section; squeezing the spring first and second coil sections causing the spring separation distance to decrease; positioning the spring adjacent to the chassis, after the squeezing the spring; releasing the spring, after the positioning the spring; positioning the cable chain proximal end between the first coil section and the second coil section, after the releasing the spring; and, attaching the cable chain to the chassis between the spring first and second coil sections thereby installing the cable chain return.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a is a perspective view of an embodiment of a cable chain return system that is in a retained position.
FIG. 1 b is a top plan view of the embodiment of the cable chain return system of FIG. 1 a.
FIG. 2 is a perspective view of the cable chain return system of FIG. 1 a in an extended position having a CRU that can be released from the cable chain.
FIG. 3 is a top plan view of the embodiment of FIG. 1 a showing a spring interfaced with the chassis.
FIG. 4 is a perspective view of the embodiment of FIG. 3 detailing a second protrusion formed in the chassis for engaging the spring.
FIG. 5 is a perspective view of the embodiment of the spring of FIG. 1 a.
FIG. 6 is a top plan view of the embodiment of the spring of FIG. 5 .
FIG. 7 is a perspective view of the cable chain being installed by a technician after the spring has been interfaced with the chassis as illustrated in FIG. 3 .
FIG. 8 is a perspective view of the cable chain return system of FIG. 7 after the cable chain has been installed and the spring biases a cable chain biased section adjacent to the chassis.
FIG. 9 is a perspective view of another embodiment of a spring interfaced with a chassis.
FIG. 10 is a top plan view of the embodiment of the chassis and the interfaced spring of FIG. 9 .
FIG. 11 is a cross-sectional view of the embodiment of the chassis and the interfaced spring taken across plane 11 - 11 of FIG. 10 .
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIGS. 1-8 , in general, illustrate an embodiment of a cable chain return system 100 provided with a cable chain 110 , a chassis 140 , a spring 170 and a customer replaceable unit (CRU) 210 . The cable chain 110 is connected between the chassis 140 and the CRU 210 . The cable chain 110 protects and carries cables 118 that provide electrical communication between electrical components (not shown) of the chassis 140 and the CRU 210 . The cable chain 110 assist in folding the cables 118 in a series of sequentially opposite curves in a “S” formation, so that the cables 118 do not become entangled during movement. The present cable chain return system 100 utilizes the spring 170 for returning the cable chain 110 after it has been extended (as illustrated in FIG. 2 ) during replacement of the CRU 210 as described later herein.
FIG. 1 a is a perspective view of one exemplary embodiment of the cable chain system 100 in a retained condition. The system 100 is provided with the cable chain 110 defining a proximal end 112 and an oppositely disposed distal end 114 . Cable chain 110 is further provided with a biased section 115 ( FIG. 2 ) adjacent to the proximal end 112 . The biased section 115 extends for a short distance of the cable chain 110 , e.g. four links of the cable chain 110 . Disposed between the proximal end 112 and distal end 114 is an interior conduit 116 for receiving the cables 118 . The cable chain 110 includes a plurality of links, e.g. individual links 120 , 122 , 124 , creating an assemblage that defines range of motion and provides the flexible interior conduit 116 for cables 118 . The cables 118 are disposed in the cable chain interior conduit 116 and flex with the cable chain 110 as illustrated in the figures.
FIG. 1 b is a top plan view of the cable chain return system 100 in the retained condition of FIG. 1 a . The cable chain 110 is folded to form a series of interlinking folds in the cable chain 110 that curve in opposite directions sequentially along the length of the cable chain 110 . The individual links 120 , 122 , 124 , etc. ( FIG. 1 a ) that form the cable chain 110 have a limited arc of rotation so that the cable links rotate in only one direction. The links of the cable chain 110 are assembled to create a plurality of folding curves 130 , e.g. first folding curve 132 , second folding curve 134 , and third folding curve 136 as desired. Some of the folding curves 130 are sequentially reversed, for example second folding curve 134 reversed from third folding curve 136 . When the folding curves 130 are sequentially reversed they can curve in sequentially opposite directions along the length of the cable chain 110 . It is desirable to ensure that the folding curves 130 are tightly formed in the retained condition, and that the folding curves 130 are properly initiated when the CRU 210 is in an extended position in the chassis 140 and begins to move to the retained position. If the folding curves 130 in the cable chain 110 are not properly initiated, the cable chain 110 may not properly initiate a folding action, which may prevent the CRU 210 from being stored in the chassis 140 in the manner illustrated in FIGS. 1 a and 1 b . The spring 170 improves proper folding of the first folding curve 132 and initiates the other folding curves 134 , 136 .
FIG. 2 shows the cable chain return system 100 in an extended condition. Cable chain 110 is extended such that the proximal end 112 is located from the distal end 114 by a separation distance 113 . The separation distance 113 changes as the cable chain return system 100 is utilized. In the retained condition, the CRU 210 is engaged to and supported by the chassis 140 and the separation distance 113 is relatively short, as illustrated in FIG. 1 b . In the extended condition, the CRU 210 is able to be disengaged and is not supported by the chassis 140 and the separation distance 113 is relatively long. In this extended condition, the cable chain return system 100 has return energy stored in the spring 170 . The return energy in the spring 170 is utilized for folding and organizing the cable chain 110 as it moves to a retained position required for the retained condition. Specifically, the return energy in the spring 170 biases the biased section 115 ( FIG. 2 ) of the cable chain 110 towards the chassis 140 . In biasing the cable chain 110 towards the chassis 140 , the first folding curve 132 is formed as best illustrated in FIG. 1 b . The particular operation of the spring 170 is detailed below.
FIG. 3 illustrates one exemplary embodiment of the chassis 140 . Chassis 140 may be configured with a c-channel section having a web 142 , a first leg 144 and a second leg 146 . The first and second legs 144 , 146 may be individual components, or as illustrated in FIG. 4 , integrally formed with the web 142 and made out of sheet metal. The chassis 140 may be configured with a variety of attachment points such as, for example, a pair of chain holes 148 , a first protrusion 150 and a second protrusion 152 .
FIG. 4 shows a perspective view of the chassis 140 of FIG. 3 . The second protrusion 152 may be formed in an L-shape having a base 154 and an integrally formed leg 156 . If integrally formed out of the chassis web 142 , the second protrusion base 154 is perpendicular and attached to the web 142 . The second protrusion leg 156 is integrally formed with the base 154 creating a feature that can capture the spring 170 as described below. The first protrusion 150 is essentially a mirror copy of the second protrusion 152 and components thereof, e.g. base 154 and leg 156 .
FIG. 5 shows a perspective view of one exemplary embodiment of the spring 170 . The spring 170 is made of any of a variety of spring materials, e.g. steel, and provided with a first coil section 172 defining a first end 174 and a second end 176 , a first lever arm 178 and a first reaction arm 180 . The first lever arm 178 protrudes from the first coil section first end 174 and the first reaction arm 180 protrudes from the first coil section second end 176 . The spring 170 may be provided with an interface arm 182 integrally formed on the end of the first lever arm 178 opposite of the first coil section 172 . The spring 170 provided with a second coil section 192 defining a first end 194 and a second end 196 , a second lever arm 198 and a second reaction arm 200 . The second lever arm 198 protrudes from the second coil section first end 194 and the second reaction arm 200 protrudes from the second coil section second end 196 . If the interface arm 182 is present, the interface arm 182 is integrally attached to the second lever arm 198 at a location opposite from the first lever arm 178 .
FIG. 6 shows a top plan view of the spring 170 having the first coil section 172 is separated from the second coil section 192 by a spring separation distance 171 . The configuration of the spring 170 allows for a force 173 and an equal but opposite force 193 to be applied to the coil sections 172 , 192 causing this spring separation distance 171 to decrease. Once the forces 173 , 193 are released, the spring separation distance 171 increases to its natural length but stopping short of its full spring separation distance 171 if it contacts any immovable components as described below.
With reference again to FIG. 1 a , the cable chain return system 100 is provided with the customer replaceable unit (CRU) 210 such as, for example, a disk drive. This CRU 210 is able to translate relative to the chassis 140 in a first direction 211 and can be detached from the chassis 140 altogether. Detaching of the CRU 210 is useful when the customer needs to replace the CRU 210 . The present cable chain return system 100 improves this replacement by providing access to the cable chain distal end 114 and electrical connectors located at the distal end 114 . The cable chain 110 , chassis 140 , spring 170 and CRU 210 are assembled in sequential steps of: 1) installation of the spring 170 onto the chassis 140 ; 2) installation of the cable chain 110 onto the chassis 140 , thereby securing the spring 170 ; and, 3) installation of the CRU 210 . The above sequential list is provided for illustrative purposes only and is one example of an embodiment that allows for easy installation. It is noted that other assembly processes may be utilized in alternative embodiments presented herein or practiced.
Referring again to FIG. 3 , the spring 170 is installed by a technician applying the first and second forces 173 , 193 to the first and second coil sections 172 , 192 , respectively. As the spring separation distance 171 ( FIG. 6 ) decreases it becomes possible to slide the coil sections 152 , 172 under the legs (e.g. second protrusion leg 156 , FIG. 4 ) of the first and second protrusions 150 , 152 , respectively. Upon locating the spring 170 as illustrated in FIG. 3 , the technician can release the forces 173 , 193 to cause the first and second coil sections 152 , 172 to come into contact with the first and second protrusions 150 , 152 , respectively. In this orientation, the first and second reactions arms 180 , 200 contact the chassis web 142 and the reaction arms 178 , 198 are free to be pivoted about the coil sections 152 , 172 , as illustrated in FIG. 7 .
FIG. 7 shows the spring 170 being manipulated by a technician (not shown). Following installation of the spring 170 described above, the cable chain 110 can be installed onto the chassis 140 . This process is aided by the pair of chain holes 148 ( FIG. 3 ) formed in the chassis web 142 . As the spring 170 is manipulated by the technician, the cable chain proximal end 112 may be attached to the chassis 140 via the chain holes 148 ( FIG. 3 ) and screws (not shown) located therein.
FIG. 8 shows a perspective view of the chassis 140 after the cable chain 110 is attached. The technician has released the spring 170 thereby causing the cable chain 110 to be biased against the chassis 140 .
Referring again to FIG. 2 , the process of installing the cable chain return system 100 is completed by attaching the CRU 210 to the distal end 114 of the cable chain 110 . There are a variety of methods known in the industry for making electrical connections; the most common is manually attaching a connector (not shown) of the cables 118 to the CRU 210 . This manual attachment of the cables 118 to the CRU 210 is possible due to the length of the cable chain 110 and the nature of the cable chain 110 itself (i.e. it can be consolidated, FIGS. 1 a and 1 b , or extended, FIG. 2 ).
Referring again to FIG. 1 a , the foregoing description of initial installation of the CRU 210 is reversed and repeated by a user to aid in maintenance and/or repair of CRUs (e.g. CRU 210 ). The user can gain access to and impart a force on the CRU 210 causing it to move in the first direction 211 into an extended condition as illustrated in FIG. 2 . The user can remove the CRU 210 by manually detaching the cables 118 ( FIG. 1 a ) and replace the CRU 210 with a replacement CRU substantial like CRU 210 . After this replacement, the user reverses the force on the CRU 210 causing the CRU 210 to move in a direction opposite from the first direction 211 . Utilizing the return energy stored in the spring 170 , the spring 170 urges the cable chain 110 towards the chassis 140 so that the process of folding the cable chain 110 when the CRU 210 is pushed into the retained position can be completed. The present cable chain return system aids in properly organizing the cable chain 110 during initial installation or replacement of the CRU 210 .
Various alternative embodiments have been contemplated by the inventors, for example, the chassis 140 may be configured as a component of a larger assembly as illustrated in FIGS. 9-11 . FIG. 9 is a perspective view of this embodiment of the chassis and a spring interfaced. FIG. 10 is a top plan view of the embodiment of the chassis and the interfaced spring of FIG. 9 . FIG. 11 is a cross-sectional view of the embodiment of the chassis and the interfaced spring taken across plane 11 - 11 of FIG. 10 .
The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variation may be possible in light of the above teachings. The embodiment was chosen and descried in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art. | Disclosed is a cable chain return system 100 that includes a spring 170 for assisting folding and organization of a cable chain 110 . When a customer replaceable unit (CRU) 210 is extended from a chassis 140 to gain access to connectors on the back of the CRU 210 , the cable chain 110 is extended. When the CRU 210 is moved back into the chassis 140 , a plurality of folding curves 130 organize the cable chain 110 , and cables 118 therein, without damaging the cables 118 or inhibiting positioning of the CRU 210 in the chassis 140 . One of these curves 130 is initiated by the spring 170 and therefore aids in returning and organizing of the cable chain 110. | 8 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to handlebar grip end caps and in particular to handlebar end caps including an engaging ring to attach the end caps.
[0002] Handlebars are used on motorcycles, bicycles, all-terrain vehicles (ATVs), watercraft and snowmobiles. Such handlebars generally include grips and end caps for closing off the ends of handlebars. Soft grips are desirable both for comfort and for control but unfortunately, make it difficult to secure an end cap at the outer end thereof. If the end cap is molded in the soft grip, it can be torn off by contact between the handlebar end and the ground. Alternatively, if grooves are formed at the end of the soft grip they do not provide sufficient structural strength to hold an end cap in place.
[0003] Several approaches have been taken to hold an end cap on a handle grip. U.S. Pat. No. 4,852,423 shows a soft grip with an end cap which is secured in a groove in the grip which is expanded by placing the grip over the handlebar. Unfortunately, the end cap is still supported by only the soft rubber grip. U.S. Pat. No. 6,112,618 provides a bicycle handgrip requiring an inside depending sidewall and an outside depending sidewall when the grip is molded from a soft material as desired. There is not sufficient structure to securely hold the end cap in place. U.S. Pat. No. 6,615,687 utilizes an end cap which is screwed into a ring. The ring in turn is held by a tubular insert. This provides a relatively expensive assembly with numerous parts and thus is impractical for most handlebar grips.
[0004] U.S. Pat. No. 5,934,154 provides a protective end cap which is an enlarged end cap to protect the user from impalement by the equipment handle. Such an end cap would be impractical for most bicycles, motorcycles and the like and would be readily knocked off when the end of the handlebar contacts the ground.
[0005] Golf clubs typically have end caps but such end caps do not have the same vulnerability to be struck against the ground as for instance a bicycle grip end cap. Various golf club end caps are shown in U.S. Pat. Nos. 3,606,325; 4,195,837; 5,895,329; and 6,718,675.
[0006] Another problem with soft grips is they tend to twist over the handlebar. Various anti-twist structures are disclosed in the prior art. U.S. Pat. No. 6,263,759 for “Removable, Non-turning Handlebar Grip,” filed by the present inventor, disclosed a soft grip with clamps at each end to fix the position of the grip on the handlebars. The clamps of the ′759 patent solved the problem of removably retaining the soft grips on handlebars, but obstruct the attachment of known end caps to the handlebars. The ′759 patent does not teach any way of securing an end cap thereto and thus there is a need for a structure which will securely hold an end cap onto a grip even though the grip portion is made from a relatively soft material. The ′759 patent is herein incorporated by reference.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention addresses the above and other needs by providing end caps which are retained by handlebar grip clamps. The grip clamps include recesses to attach to protrusions on an outside end of handlebar grips, circumferential portions which clamp against the handlebar, and outward facing mouths with inside grooves. The grip clamps may be loosely attached to the handle grips allowing insertable portions of the end caps to be inserted into the mouths. The insertable portions include tapered portions to facilitate insertion into the mouths of the loosely tightened clamps, and raised captured portions and recessed portions for retention of the end caps by the inside grooves of the mouths. The grip clamps may then be tightened onto the handlebars and thereby both lock the handlebar grips onto the handlebars and retain the end caps. Damaged end caps may later be replaced by loosening the clamps without requiring removal of the clamps or the grips for easy repair.
[0008] In accordance with one aspect of the invention, there is provided a handlebar grip and end cap assembly including a hollow grip, a clamp, and an end cap. The hollow grip resides over a handlebar end and includes an outside grip end with arced protrusions. The clamp resides adjacent to the outside grip end and includes recesses in an inner end of the clamp for cooperation with the protrusions to grasp the grip, interior circumferential portions for clamping the clamp against the handlebar end, and an outer end of the clamp. The outer end includes a mouth residing inside the outer end and an inside groove residing inside the mouth. The end cap resides adjacent to the outer end of the clamp and includes a face facing outward from the grip, a substantially cylindrical waist residing between the face and the outer end of the grip, and an insertable portion opposite the face and protruding from the waist and removably insertable into the mouth of the outer clamp. The insertable portion includes a tapered portion, a capture portion, and a recessed portion. The tapered portion is farthest from the waist at an innermost end of the insertable portion and tapers from a smaller diameter end facing into the grip to a greater diameter end opposite the smaller diameter end. The captured portion residing adjacent to the tapered portion and has approximately the same diameter as the greater diameter end of the tapered portion. The recessed portion between the captured portion and the waist and having a smaller diameter than the captured portion. A radially extending first wall resides between the recessed portion and the captured portion.
[0009] In accordance with one aspect of the invention, there is provided a handlebar grip and end cap assembly including a hollow grip, an outer clamp, and an end cap. The hollow grip resides over a handlebar end and has an outside grip end. The outer clamp resides adjacent to the outside grip end and grasps the grip and grasps the handlebars. The outside clamp includes an outer end, a mouth residing inside the outer end, and an inside groove residing inside the mouth. The inside grove has a groove face defining an outside edge of the groove and is approximately orthogonal to an axial centerline through the clamp. The end cap resides adjacent to the outer end of the clamp and includes a face facing outward from the grip, a substantially cylindrical waist residing between the face and the outer end of the grip, and an insertable portion opposite said face and protruding from said waist and removably inserted into the mouth of the outer clamp. The insertable portion includes a tapered portion, a captured portion, and a recessed portion. The tapered portion resides at an innermost end of the insertable portion and tapers from a smaller diameter end facing into the grip to a greater diameter end opposite the smaller diameter end. The captured portion resides adjacent to the tapered portion and has approximately the same diameter as the greater diameter end of the tapered portion. The recessed portion resides adjacent to and behind the captured portion and having a smaller diameter than the captured portion. A first wall extends radially between the recessed portion and the captured portion and a sharp edge resides between the first wall and the captured portion.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:
[0011] FIG. 1 is a perspective view of a grip, a clamp, and an end cap according to the present invention on a handlebar end.
[0012] FIG. 2 is a cross-sectional view of the grip, clamp, and end cap taken along line 2 - 2 of FIG. 1 .
[0013] FIG. 3 is a cross-sectional view of the grip, clamp, and end cap taken along line 3 - 3 of FIG. 2 .
[0014] FIG. 4 is a detailed cross-sectional view of the cooperation of the clamp and the end cap taken from detail 4 of FIG. 2 .
[0015] FIG. 5A is a detailed view of a cross-section of a captured portion of the end cap taken from detail 5 of FIG. 4 .
[0016] FIG. 5B is a detailed view of a cross-section of a mouth of the outer clamp taken from detail 5 of FIG. 4 .
[0017] FIG. 6 is an exploded perspective view of cooperating surfaces of the clamp and grip.
[0018] FIG. 7 is a perspective view of the outer clamp showing the mouth and inside groove.
[0019] FIG. 8 is a perspective view of an end cap according to the present invention.
[0020] Corresponding reference characters indicate corresponding components throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims.
[0022] A perspective view of a handlebar grip 10 , ridged inner and outer grip clamps 27 and 28 , and an end cap 38 according to the present invention, residing at an outer end 10 a of the grip 10 on a handlebar end 11 , is shown in FIG. 1 . The handlebar end 11 represents one end of typical handlebars. The handlebar grip 10 is affixed along a grip receiving length 13 (shown in FIG. 2 ) of a cylindrical outer surface 14 of the handlebar end 11 (shown in FIG. 3 ). The handlebar end 11 has an outside diameter D. The handlebar grip 10 has an inner rigid shell 16 which has an inner surface 17 which slides over the cylindrical outer surface 14 of handlebar end 11 . The inner rigid shell 16 has an outer surface 17 ′, a first end 18 and a second end 19 . A pair of lengthwise arced protrusions 20 and 20 ′ are formed at the first end 18 of the inner rigid shell 16 and a pair of lengthwise arced protrusions 21 and 21 ′ are formed at the second end 19 of the inner rigid shell 16 . An outer flexible grip 22 is secured to the outer surface 17 ′ of inner rigid shell 16 . The outer flexible grip 22 has an inner surface 23 which is preferably secured by an adhesive to outer surface 17 ′. The outer surface 24 of the outer flexible grip 23 is preferably knurled or otherwise covered with a pattern which assists in the holding of the grip. Outer flexible grip 22 has a first end 25 and a second end 26 and can be molded from a relatively soft material to provide rider comfort.
[0023] The clamp 27 and the clamp 28 , securing the inner rigid shell 16 to the handlebar end 11 , are shown in FIG. 2 , in a cross-sectional view taken along line 2 - 2 of FIG. 1 . A cross-sectional view of the clamp 28 and arced protrusions 21 and 21 ′ taken along line 3 - 3 of FIG. 2 is shown in FIG. 3 , where the outside diameter D of the handlebar end 11 is indicated. It may also be seen that the lengthwise protrusions 21 and 21 ′ are held within a pair of recesses 30 and 30 ′ of the outer clamp 28 . This interconnection is best understood by viewing FIG. 6 which shows the outer clamp 28 and where the shell protrusion receiving recesses 30 and 30 ′ are clearly seen.
[0024] The clamps 27 and 28 may be held to the handlebar end 11 in various ways. For example, an Allen screw 32 (or other threaded fastener) spanning a gap 34 and threaded into a threaded opening 33 on an opposite side of the gap 34 . Tightening the Allen screw 32 closes the gap 34 forcing the clamp 28 against the handlebar end 11 . In use, the inner and outer clamps 27 and 28 are placed over the protrusions 20 and 20 ′ and 21 and 21 ′. This assembly is slid over the end 12 of the handlebar end 11 and the two rigid clamps 27 and 28 are tightened by tightening Allen screws 32 .
[0025] The inner rigid shell 16 is preferably fabricated from a durable and impact resistant polymer such as glass filled polypropylene. Of course, the term “rigid” is a relative one. Glass filled polypropylene has some flexibility, but, compared to the grip elastomer, is considered rigid. The clamps 27 and 28 are preferably made of metal, and preferably of aluminum which is considerably more rigid than glass filled polypropylene. The grip 10 is preferably fabricated from a relative soft elastomer such as a plasticized rubber of the type sold under the trademarks “J. Von,” “Krayton,” and “Starflex” having a hardness of typically 15 durometer.
[0026] As can be seen in FIGS. 3 and 4 , rigid clamp 28 not only captures protrusion 21 with recess 30 , but also clamps against the surface 14 of handlebar end 11 along the inner gripping surface 29 of rigid clamp 28 . This metal clamp to metal handlebar contact provides a very secure clamping action against the handlebar end 11 without unduly compressing inner rigid shell 16 or its protrusions 21 and 21 ′.
[0027] Furthermore, there are two interior circumferential portions 39 and 40 on an interior surface of each rigid clamp 27 and 28 which also contact the outer surface 14 of handlebar end 11 . This further helps to secure the rigid clamps to the handlebar end and thereby secure the inner rigid shell thereto. There are, additionally, pairs of spaces 35 and 36 between protrusions 20 and 20 ′ as shown in FIG. 6 , which permit the full contact at portions 39 and 40 of the rigid clamps 27 and 28 . The result is a pair of handlebar grips which are very securely affixed to the handlebar and yet, can be rapidly removed by loosening Allen screws 32 and sliding off the handlebar and replaced with another grip quickly if desired.
[0028] The end cap 38 is shown residing over the outer end 10 a of the grip 10 , and in this instance, over the outer end the clamp 28 .
[0029] A detailed cross-sectional view of the cooperation of the clamp 28 and the end cap 38 taken from detail 4 of FIG. 2 . is shown in FIG. 4 . The engagement of an insertable portion 50 of the end cap 38 into a mouth 46 (see FIG. 7 ) of the clamp 28 allows the securing of the end cap 38 to the clamp 28 and thereby to the grip 10 . A captured portion 54 (see FIG. 5A ) of the insertable portion 50 engages an inside groove 48 (see FIG. 5B ) in the mouth 46 to retain the end cap 38 . The position of the insertable portion 50 inside the mouth 46 allows tightening of the Allen screw 32 to also tighten the clamp 28 on the insertable portion 50 of the end cap 38 .
[0030] A detailed view of a cross-section of an insertable portion 50 of the end cap 38 taken from detail 5 of FIG. 4 is shown in FIG. 5A . The insertable portion 50 includes a tapered portion 56 , the captured portion 54 , and a recessed portion 52 . The recessed portion 52 is nearest to the waist 38 b (see FIG. 8 ) is preferably cylindrical and preferably extends axially (i.e., approximately coaxial with the axis 28 a of the clamp 28 ) a distance w 1 between approximately 0.026 inches and approximately 0.034 inches, and is preferably between approximately 0.006 inches and approximately 0.010 inches deep. The captured portion 54 is adjacent to the recessed portion 52 and is preferably approximately cylindrical and approximately coaxial with the axis 28 a and preferably extends axially a distance w 2 of between approximately 0.006 inches and approximately 0.014 inches. The tapered portion 56 is adjacent to the capture portion 54 and opposite the recessed portion 52 and is preferably approximately frusto-conical in shape and approximately coaxial with the axis 28 a and preferably extends axially a distance w 3 between approximately 0.015 inches and approximately 0.025 inches and preferably has a taper a 1 from a greater diameter adjacent to the captured portion 54 to a smaller diameter, of between approximately 29 degrees and approximately 31 degrees, and more preferably has a taper of approximately 30 degrees. A first wall 60 separates the captured portion 54 from the recessed portion 52 . The first wall 60 is preferably flat and resides approximately orthogonal to the axis 28 a and preferably meets the captured portion 54 at a sharp corner 58 .
[0031] A detailed view of a cross-section of a portion of the mouth 46 of the outer clamp 28 taken from detail 5 of FIG. 4 is shown in FIG. 5B . The mouth 46 includes the inside groove 48 for retaining the insertable portion 50 in the mouth 46 . The inside groove 48 includes a second wall 48 a for cooperation with the first wall 60 to retain the end cap 38 in the outer clamp 28 . The second wall 48 a is preferably approximately orthogonal to the axis 28 a (see FIG. 2 ) of the clamp 28 and the inside groove 48 preferably has a rectangular cross-section and is preferably approximately 0.040 inches wide and approximately 0.012 inches deep.
[0032] An exploded perspective view of cooperating surfaces of the outer clamp 28 and grip 10 is shown in FIG. 6 . The recesses 30 and 30 ′ are concave and capture the protrusions 20 and 20 ′ so that one clamp 27 or 28 may hold the handlebar grip 10 on the handlebar end 11 since it cannot slide out of the clamp 27 or 28 when clamp 27 or 28 is tightened.
[0033] A perspective view of the outer clamp 28 showing the mouth 46 and the inside groove 48 is shown in FIG. 7 .
[0034] A perspective view of the cap end 38 showing a face 38 a and a waist 38 b is shown in FIG. 8 . The face 38 a is preferably substantially round, for example, has at least a round appearance, but may also be oval or polygonal shaped. The waist 38 b is preferably substantially cylindrical, for example, appears cylindrical, and more preferably is approximately cylindrical with approximately the same diameter as the clamp 28 . The end cap 38 is preferably made from Nylon material, and more preferably from glass fiber filled Nylon material, and most preferably from 15% glass fiber filled Nylon material.
[0035] While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims. | End caps are retained by handlebar grip clamps. The grip clamps include recesses to attach to protrusions on an outside end of handlebar grips, interior circumferential portions which clamp against the handlebar, and outward facing mouths with inside grooves. The grip clamps may be loosely attached to the handle grips allowing insertable portions of the end caps to be inserted into the mouths. The insertable portions include tapered portions to facilitate insertion into the mouths of the loosely tightened clamps, and raised captured portions and recessed portions for retention of the end caps by the inside grooves of the mouths. The grip clamps may then be tightened onto the handlebars and thereby both lock the handlebar grips onto the handlebars and retain the end caps. Damaged end caps may later be replaced by loosening the clamps without requiring removal of the clamps or the grips for easy repair. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under 35 U.S.C. 119 of provisional application 61/411,053 filed on Nov. 8, 2010 entitled “An Augmented Reality Interface for Video Tagging and Sharing” which is hereby incorporated by reference in its entirety, and is related to seven other simultaneously-filed applications, including U.S application Ser. No. 13/291,836 entitled “Augmented Reality Interface for Video”, U.S. application Ser. No. 13/291,851 entitled “Augmented Reality Interface for Video Tagging and Sharing”, U.S. Application Ser. No. 13/291,886 entitled “Augmented Reality System for Position Identification”, U.S. application Ser. No. 13/291,903 entitled “Augmented Reality System for Supplementing and Blending Data”, U.S application Ser. No. 13/291,918 entitled “Augmented Reality Virtual Guide System”, U.S. application Ser. No. 13/291,930 entitled “Augmented Reality System for Product Identification and Promotion”, U.S. application Ser. No. 13/291,951 entitled “Augmented Reality Surveillance and Rescue System”, each of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present patent document relates in general to augmented reality systems, more specifically to relating stored images and videos to those currently obtained by an observer's portable electronic device.
BACKGROUND OF THE INVENTION
Modern portable electronic devices are becoming increasingly powerful and sophisticated. Not only are devices running faster CPUs, they're also equipped with sensors that are making these devices more versatile than traditional personal computers. The use of GPS, gyroscopes, accelerometers have made these devices location aware, and opened up a world of possible applications that did not seem possible before.
The standard definition of augmented reality is live direct or indirect viewing of a physical real-world environment whose elements are augmented by virtual computer-generated imagery. Traditionally augmented reality applications have been limited to expensive custom setups used in universities and academia, but with the advent of modem smartphones and powerful embedded processors, many of the algorithms that were once confined to the personal computer world are becoming a part of the mobile world. Layar and AroundMe are examples of two such applications that are increasingly popular and have been ported to many smartphones (Layar is a product of the company Layar, of the Netherlands, and AroundMe is a product of the company Tweakersoft). Both the Layar and AroundMe applications use location data obtained from GPS sensors to overlay additional information such as direction and distance of nearby landmarks.
Typically, augmented reality implementations have relied on three elemental technologies:
(1) Sensing technologies to identify locations or sites in real space using markers, image recognition algorithms, and sensors.
(2) Information retrieval and overlay technologies to create virtual information and to overlay it on top of live images captured by the camera.
(3) Display technologies capable of integrating real and virtual information which includes mobile phone display, projectors, as well as augmented reality glasses.
In addition, mobile augmented reality techniques are roughly classified into two types based on the type of sensing technology used.
A. Location Based Augmented Reality
Location based augmented reality techniques determine the location or orientation of a device using GPS or other sensor, then overlay the camera display with information relevant to the place or direction. The four common sensor platforms used are described below:
GPS: The Global Positioning System provides worldwide coverage and measures the user's 3D position, typically within 30 meters for regular GPS, and about 3 meters for differential GPS. It does not measure orientation. One of the major drawbacks of using GPS based systems is that they require direct line-of-sight views to the satellites and are commonly blocked in urban areas, canyons, etc. This limits their usability severely. Inertial, geomagnetic, and dead reckoning: Inertial sensors are sourceless and relatively immune to environmental disturbances. Their main drawback however is that they accumulate drift over a period of time. The key to using inertial sensors therefore lies in developing efficient filtering and correction algorithm that can compensate for this drift error. Active sources: For indoor virtual environments, a common approach is the use of active transmitters and receivers (using magnetic, optical, or ultrasonic technologies). The obvious disadvantage of these systems is that modifying the environment in this manner outdoors is usually not practical and restricts the user to the location of the active sources. Passive optical: This method relies on using video or optical sensors to track the sun, stars, or surrounding environment, to determine a frame of reference. However most augmented reality applications refrain from using these algorithms since they are computationally intensive.
B) Vision Based Augmented Reality
Vision based augmented reality techniques attempt to model precise descriptions of the shape and location of the real objects in the environment using image processing techniques or predefined markers, and use the information obtained to align the virtual graphical overlay. These techniques may be subdivided into two main categories.
Marker Based Augmented Reality: Marker based augmented reality systems involve recognition of a particular marker called an augmented reality marker with a camera, and then overlaying information on the display that matches the marker. These markers are usually simple monochrome markers and may be detected fairly easily using less complex image processing algorithms. Markerless augmented reality: Markerless based augmented reality systems recognize a location or an object not by augmented reality markers but by image feature analysis, then combine information with the live image captured by the camera. A well-known example of this image tracking approach is Parallel Tracking and Mapping (PTAM) developed by Oxford University and Speeded Up Robust Features (SURF) which has been recently used by Nokia Research.
Even though these techniques have been deployed and used extensively in the mobile space, there are still several technical challenges that need to be addressed for a robust, usable augmented reality system.
There are three main challenges discussed hereafter:
I. Existing Mobile rendering APIs are not optimal
Existing Mobile 3D solutions are cumbersome and impose limitations on seamless integration with live camera imagery. For complete integration between live camera and overlaid information, the graphics overlay needs to be transformed and rendered in real-time based on the user's position, orientation, and heading. The accuracy of the rendering is important since augmented reality applications offer a rich user experience by precisely registering and orienting overlaid information with elements in user's surroundings. Precise overlay of graphical information over a camera image creates a more intuitive presentation. User experience therefore degrades quickly when accuracy is lost. There have been several implementations that have achieved fast rendering by using OpenGL, or by remote rendering the information and streaming the video to mobile embedded devices. Most modern smartphones have graphics libraries such as OpenGL that use the inbuilt GPU to offload the more computationally expensive rendering operations so that other CPU intensive tasks such as the loading of points of interest are not blocked. However the use of OpenGL on smartphone platforms introduces other challenges. One of the biggest disadvantages of using OpenGL is that once perspective-rendered content is displayed onscreen, it is hard to perform hit testing because OpenGL ES 1.1 does not provide APIs for “picking mode” or “selection” used to determine the geometry at particular screen coordinates. When controls are rendered in a perspective view, it is hard to determine whether touch events lie within the control bounds. Therefore, even though OpenGL supports perspective 3D rendering under the processing constraints typical of modem mobile smartphones, it is not optimal.
II. Real-time marker/markerless systems are too complex
Real-time detection and registration of a frame reference is computationally expensive, especially for markerless techniques. Mapping a virtual environment onto the real-world coordinate space requires complex algorithms. To create a compelling experience, the virtual viewport must update quickly to reflect changes in the camera's orientation, heading, and perspective as the user moves the camera. This makes it essential to gather information about the device's physical position in the environment in real-time. Traditional techniques for frame of reference estimation depend on identifiable markers embedded in the environment or computationally-intensive image processing algorithms to extract registration features. Most of these image processing techniques need to be optimized extensively to fit within the hardware constraints imposed by mobile devices. For closed environments where markers may be placed beforehand, the use of identifiable markers for detection and frame of reference estimation is usually the best viable option. This approach, however, is less suitable for augmented reality applications in outdoor environments since setting up the environment with markers prior to the application's use is unlikely. Attempts to perform real time natural feature detection and tracking on modem mobile devices have been largely intractable since they use large amounts of cached data and significant processing power.
III. Sensor data for location based systems is inaccurate
For location based augmented reality systems, especially GPS based systems, sensor noise makes orientation estimation difficult. Modem mobile smartphones contain a number of sensors that are applicable for augmented reality applications. For example, cameras are ubiquitous and accelerometers and geomagnetic sensors are available in most smartphones. Geomagnetic and gyroscope sensors provide information about users headings and angular rate which may be combined with GPS data to estimate field of view and location. However these sensors present unique problems, as they do not provide highly accurate readings and are sensitive to noise. To map the virtual augmented reality environment into a real-world coordinate space, sensor data must be accurate and free of noise that may cause jittering in rendered overlays. The reduction of noise thus represents a significant challenge confronting augmented reality software.
This patent application provides viable approaches to solve these challenges and present a practical implementation of those techniques on a mobile phone. A new methodology for localizing, tagging, and viewing video augmented with existing camera systems is presented. A smartphone implementation is termed “Looking Glass”.
SUMMARY OF THE EMBODIMENTS
A system, method, and computer program product for an augmented reality interface are disclosed and claimed herein. Exemplary embodiments may comprise acquiring an image of a real-world scene and metadata with a camera, storing the image and metadata, retrieving at least one stored image with metadata having selected features, manipulating the retrieved image, and combining the manipulated image with a currently observed real-world scene viewed with a portable electronic device. The image may include a still photograph, at least one video frame up to a full video. The image may be in analog or digital format, and may be recorded or live. The image may be communicated in a data stream. The metadata may describe the physical location and orientation of the camera during the acquiring, and may be provided by a GPS system, a gyroscope, and/or an accelerometer. The metadata may be provided by the camera.
The currently observed scene, images, and/or metadata may be stored on a server and/or the portable electronic device. The selected features may include the stored physical location and orientation best matching a current physical location and orientation of the portable electronic device. Alternately, the selected features may include the stored physical location and orientation best matching at least one predicted physical location and orientation of the portable electronic device. The server may search for the selected features, and the retrieved image may be in a second data stream. The portable electronic device may include a smartphone, a hand-held device, the camera, a second camera, a PDA, and/or a tablet computer. The embodiment may manipulate the retrieved image by adjusting image orientation.
The embodiment may superimpose the manipulated image on the currently observed scene, which may involve merging the data stream with the second data stream. The embodiment may combine manipulated imagery by displaying the manipulated image with the portable electronic device in a display or a viewfinder. The method preferably operates continuously and substantially in real time. The method may operate as the currently observed scene changes as the portable electronic device is moved, including translating, tilting, panning, and zooming.
A system embodiment may comprise a processor and a memory containing instructions that, when executed by the processor cause the processor to acquire a video of a real-world scene and metadata with a camera, store the video and metadata, retrieve at least one stored video with metadata having selected features, manipulate the retrieved video, and combine the manipulated video with a currently observed real-world scene viewed with a portable electronic device.
A computer program product embodiment may comprise a computer readable medium tangibly embodying non-transitory computer-executable program instructions thereon that, when executed, cause a computing device to acquire a video of a real-world scene and metadata with a camera, store the video and metadata, retrieve at least one stored video with metadata having selected features, manipulate the retrieved video, and combine the manipulated video with a currently observed real-world scene viewed with a portable electronic device.
In a second embodiment, the metadata may include annotations by a server or a user acquiring the video. The annotations may include details of a person, an object, or a location being photographed. The annotations may help users share their experiences and/or recommended locations. The acquiring and retrieving of imagery may be performed by different persons, including friends or clients for example.
In a third embodiment, the video and metadata may be communicated on at least one network. The retrieving may include pushing the data stream to a network, or pulling the data from a network in response to a request. The network may include a private network or the interne.
In a fourth embodiment, the retrieved video may be compared with the currently observed real-world scene to enable navigation. The embodiment may visually verify a real-world path or a real-world destination for a portable electronic device user.
In a fifth embodiment, the manipulated video may be combined with at least one historical image and a currently observed real-world scene viewed with a portable electronic device. This embodiment thus may place the user in a historically-based reality, to for example assist in educating the user on historical events.
In a sixth embodiment, guide information related to the selected features is provided. The guide information may include historical information and/or current information. The guide information may include a virtual tour with commentary regarding identified landmarks, museum exhibits, real properties for sale, and/or rental properties. Access to the guide information may be provided as a fee-based service.
In a seventh embodiment, commercial information regarding the selected features is provided. The selected features may include goods or services available commercially. The commercial information may include a recommendation, a review, a promotion, an advertisement, a price, an online vendor, a local vendor, a descriptive differentiation presentation, or a UPC.
In an eighth embodiment, the metadata may include descriptive data relating to at least one of surveillance and rescue. For example, the metadata may include at least one of the position and orientation of an item of police evidence. The metadata may also include information relating to a lost child, an invalid, an elderly person, or a medical emergency.
As described more fully below, the apparatus and processes of the embodiments disclosed provide an augmented reality interface. Further aspects, objects, desirable features, and advantages of the apparatus and methods disclosed herein will be better understood and apparent to one skilled in the relevant art in view of the detailed description and drawings that follow, in which various embodiments are illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a depicts a position confidence ellipse using dead reckoning;
FIG. 2 depicts the basic algorithm for filtering a compass heading according to an embodiment;
FIG. 3 depicts the results of the filtering algorithm on raw sensor data within an iPhone implementation according to an embodiment;
FIG. 4 depicts grid based location querying to retrieve and upload virtual content according to an embodiment;
FIG. 5 depicts a scene that a user wants to tag and upload to a server according to an embodiment;
FIG. 6 depicts an interface for recording, tagging, and uploading a video of a scene according to an embodiment;
FIG. 7 depicts that metadata is uploaded from a device to a server that contains both video data as well as additional location metadata according to an embodiment;
FIG. 8 depicts how a live camera image is augmented with user video which may be either streamed or pre-downloaded based on user position and orientation according to an embodiment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The challenges mentioned above are now addressed, and implementations of the present invention tackle each of the three challenges specifically. Existing mobile rendering APIs are not optimal; they impose certain intractable limitations on the interaction between the live and augmented view. To mitigate these issues, the implementations of the present invention rely on simple scene graphs based on a nested view approach to render the content overlay. Each view has a 4×4 visual transformation matrix, which supports basic perspective rendering. The transformation matrix is applied to graphics output when each view draws its respective content, and is also applied to user interaction events as they are passed into the view stack. The created transformation matrix approximates the perspective distortion caused by the camera movement, and applies the transformation to all views within the nested tree. This enables easy rendering of interactive buttons on the screen, and precludes the need to use other graphics libraries, such as OpenGL. It also enables user interaction with rendered content, which is important for mobile augmented reality applications. Most mobile APIs provide view/widget nesting mechanisms as well as custom APIs for manipulating transform matrices. This technique therefore provides the most flexibility for most augmented reality applications since at any given time there are not many transformations that need to be handled. However, it must be noted that as the complexity of the rendering increases, there will be a marked decrease in performance since all the transformations are being done in software.
To test this approach, this nested view transformation was implemented on the iPhone 4 (iPhone is a registered trademark of Apple Computer, Inc.). Tests showed that up to 23 different separate views may be shown on the screen without any performance degradation. As a result of this investigation, it was determined that most mobile APIs, such as those for Android (Android is a trademark of Google, Inc.) and more recently iPhone SDK 4.1, the video data may be exposed and nested in views using the same technique. This allows the implementation of an augmented reality application which not only augments the live camera imagery with graphics or text, but another live or recorded video.
Another one of the challenges discussed earlier was the computational complexity involved in identifying frames of reference and correspondence. This is one of the most crucial aspects of augmented reality technologies. Using markers certainly solves the frame of reference issue. However, it is impractical for most mobile augmented reality applications since it requires customized markers to be placed. Markerless approaches attempt to solve these issues by using CPU intensive image recognition algorithms to identify features which may be used to determine a frame of reference, location and position of the virtual overlay with respect to the live camera image. These techniques however, are impractical on most mobile devices since they have limited CPUs. On the other hand, using GPS sensors to locate position works for most cases and most modern smart phones are equipped with GPS as well as digital compass sensors. The drawback of using these sensors is that they are susceptible to noise and GPS sensors cannot be used indoors which severely limits their use for indoor applications.
It is clear that none of the techniques on their own may be used to create a complete augmented reality system that works in all scenarios. Therefore, these limitations were addressed by using a hybrid approach. Embodiments of the present invention use a combination of GPS sensor, digital compass, gyroscope information as well as a modified markerless feature tracking algorithm to achieve real time image registration and location estimation that may be used in any scenario. These techniques were implemented as an iPhone 4 application, since it provides the best combination of sensors that are required for this approach.
The iPhone 4 contains AGD 1 which is a 3 axis gyroscope/accelerometer as well as a magnetic sensor which provides directional information. It also contains a GPS chip. Recent studies using the iPhone 4 SDK have shown the background location notification for the GPS has an accuracy of approximately 500 meters and an active accuracy of around 30 meters when there is a full signal lock. This is a pretty large range, therefore to get a more refined and consistent location information, the embodiments of the present invention combine the information from the digital compass as well as the gyroscope information to determine if a user was moving, and used the directional as well as the movement data to approximate location within a 500×500 meter grid. The use of 3-axis gyros to determine location is not new and is used in most inertial navigation systems. This technique is usually referred to as dead reckoning.
Dead reckoning is the process of estimating present position by projecting heading and speed from a known past position. The heading and speed are combined into a movement vector representing the change of position from a known position, P 0 , to an estimated position, P 1 . The accuracy of this estimation may be quoted as a confidence ellipse whose population mean is in the ellipse 95% of the time. The axes of the ellipse are determined by the accuracies of the heading detection and speed measurement. This is illustrated in FIG. 1 , which depicts a position confidence ellipse 100 using dead reckoning.
A user moving from point P 0 to point P 1 may be described as being within the 95% confidence ellipse 100 centered on P 1 with axes ab, determined by the heading sensor accuracy, and cd, determined by the speed sensor accuracy. While the uncertainty of a single reading may be described this way, the uncertainty of multiple readings is calculated as the cumulative sum of the uncertainty on all readings since the last precisely known position. This is simply expressed in the equation
Pn = P 0 + ∑ i = 0 i = n ( vi + ve )
where n is the number of dead reckoning calculations since P 0 , P n is the current position, and v e is the error vector for each calculation.
Assuming a straight path, the resultant confidence ellipse after n iterations has axes of dimension n×ab and n×cd, or more simply, in the worst case these ellipses grow linearly with travel distance. Clearly the accuracy of the sensors is critical to the confidence that may be placed in position estimation using dead reckoning. Unfortunately the sensors on most mobile smart phones are inaccurate and are severely impacted by noise. As a result a number of noise filtering algorithms were investigated, including Kalman filter based dead reckoning, and the Savitzky-Golay smoothing filter, however none of these seemed suitable for real time performance on mobile phone systems. It was finally decided to implement a finite impulse response filter, a method proposed by J. Benjamin Gotow et al. They recently proved that an adapted FIR filter may be used successfully on iPhone as well as Android phones with acceptable accuracy. In addition, the more advanced Savitzky-Golay smoothing filter may be applied offline by uploading the raw sensor data to a backend server which may run the data and then provide corrections to algorithm periodically. FIG. 2 outlines the basic algorithm for filtering compass heading.
FIG. 3 shows the results of the filtering algorithm on raw sensor data within an iPhone implementation. In this accelerometer filter implementation, different colors (not shown) may be used to represent accelerations in different orthogonal axes.
In the preferred embodiment, this technique allows users to record video and tag it with its current location. This tag contains additional metadata that is uploaded to a server and is associated with video file. The format of the metadata not only contains longitude, latitude, and heading data but also grid coordinates that are calculated based on the location estimation obtained once the GPS coordinates match and the dead reckoning algorithm kicks in. This grid based approach to data storage and point of interest retrieval has several benefits. In areas where there are a large number of points of interest, such as cities, retrieving and caching a large number of geotagged points becomes difficult. As the user moves, the system has to continuously query its backend server to update the nearest points of interest.
Unfortunately, there are several problems with this straightforward approach. First of all, such a system is not scalable, as the number of users increase querying the database constantly severely degrades performance. A different approach is needed to avoid the execution of expensive database queries. Requesting and retrieving data on a mobile smartphone is also problematic as continuous network connectivity quickly depletes the battery, and constantly uploading to and retrieving data from servers may adversely affect the frame rate of the application. One way to solve this issue is to cache the data based on approximate geolocations which are divided and stored as indexed grid coordinates in the database.
FIG. 4 depicts grid based location querying to retrieve and upload virtual content. This grid based approach provides a scalable approach for information retrieval and caching for mobile devices. It progressively loads contents from a server based on GPS coordinates. A hash function places each point denoted by its latitude/longitude and sub grid location based on accelerometer data into an indexed two-dimensional grid.
Each longitude/latitude square in the grid contains all points within a specific geographical area, and may be loaded by querying the database for the indexed coordinate values. Each square is further subdivided into the 50×50 grid, each of which indexes a location roughly 10 square meters. This grid is indexed based on approximate location within a single longitudinal/latitudinal grid which is based on information obtained from the filtering of the gyroscope data. Indexing the contents of the database using discretized latitude and longitude values obviates the need for numeric comparison and queries bounded by latitude and longitude values. Queries may specify an exact block index and retrieve a group of points within a predefined geographic area.
There are several advantages of dividing content into a grid and retrieving it on block by block basis. Information may be retrieved and cached using just indexes. Each content item may be uniquely identified with 4 index numbers, two specifying its longitude/latitude square and two specifying its sub-grid position. This alleviates the need for complex retrieval queries on a central server. Caching retrieved data is also straightforward since data may be stored and retrieved on the device based on the block index. Purging cached data based on its distance from the user's current location does not require iterating through each cached point. Instead, entire blocks may be quickly deleted from the cache by using the discrete grid indexes. In addition, filtering blocks of points is much more efficient than processing each point and also requires constant evaluation time, regardless of the number of points present in the area.
In addition to using accurate location information, embodiments of the present invention enhance the accuracy of the frame of reference by analyzing the individual camera frame for natural features. There has been considerable research in markerless augmented reality algorithms; techniques such as PTAM, SURF, and SIFT have all been proven to be efficient descriptors for augmented reality applications in mobile devices. However all of these techniques are usually used on their own and therefore are not suitable for hybrid techniques such as those needed for implementations of the present invention which needs to calculate and filter location data, as well as extract image features all at the same times without decreasing the real time performance of the system. Therefore a simpler image descriptor is required, which may be calculated efficiently on a mobile device.
Recently, Edward Rosten et al presented a fast, efficient corner detection algorithm called FAST, which stands for Features from Accelerated Segment Test. The feature detector considers pixels in a Bresenhams circle of radius r around the candidate point. If n contiguous pixels are all brighter than the nucleus by at least given threshold value t or all darker than the nucleus by given threshold value t, then the pixel under the nucleus is considered to be a feature. Although r can in principle take any value, only a value of 3 is used (corresponding to a circle of 16 pixels circumference), and tests show that the best value of n is 9. This value of n is the lowest one at which edges are not detected. The resulting detector produces very stable features. Additionally, FAST uses the ID3 algorithm to optimize the order in which pixels are tested, resulting in the most computationally efficient feature detector available. ID3 stands for Iterative Dichotomiser 3, an algorithm used to generate a heuristic decision tree. It is an approximation algorithm that relies on Occam's razor rule to form the decision tree.
The ID3 algorithm may be summarized as follows:
1. Take all unused attributes and count their entropy concerning test samples
2. Choose attributes for which entropy is minimum (or, equivalently, information gain is maximum)
3. Make a node containing that attribute
In embodiments of the present invention, uploaded video on the server is analyzed for corners features. The entropy in this case is defined as the likelihood that the current pixel being analyzed is part of a corner. This likelihood is calculated based on the intensity of the current pixel with respect to its neighboring pixels. Fast corner features are also extracted for each camera image at every frame and matched against those retrieved from the database. A signed distance metric is used to correct frame orientation and position to best align the virtual view with live camera imagery.
The implementation of the hybrid augmented reality algorithm detailed in the previous section is now presented. “Looking Glass” is an augmented reality based video tagging and sharing application. As mentioned before, the choice of platform was the iPhone 4, as it contained a 3 direction gyro and a stable SDK which made the implementation easier. However it should be noted that these same techniques may be easily ported to Android or any other CE platform as well, as long as they have a hardware profile similar to that of the iPhone 4G.
The application may be divided into three distinct stages:
In the first stage, the user may record and tag any video taken from an iPhone 4 with location, orientation and gyroscope data obtained from the GPS coordinates and the gyroscope filtering. This additional information is stored in a special binary file and associated with each video. Users may record video within the application itself and tag it with description or comments. When the user is finished, the application collates the location and gyroscope information along with the tag information and sends it to the backend server. FIGS. 5 and 6 depict a scene that a user wants to tag and upload to a server, and the iPhone application interface for recording, tagging, and uploading a video of the scene, respectively.
In the second stage, the tagged videos are uploaded either during the next time the device is connected to a personal computer or when it connects to a Wifi network. Both the video as well as the metadata file are sent to the server. The server annotates the metadata file with additional information that is obtained by analyzing the video frames. Each video snippet may be sampled at 10 second intervals and from those samples FAST (Features from Accelerated Segment Test) features are obtained; these features may be used later to provide image registration information to assist overlay. FIG. 7 depicts that metadata is uploaded from the phone to a server that contains both user video data as well as additional location metadata.
FIG. 8 depicts how a live camera image is augmented with user video, which may be either streamed or pre-downloaded. The third stage of the methodology involves buffering the video snippets from the server to the user interface based on location and orientation information. Given the current location of the device, the server may determine the videos that will be within the device's view and preload the smaller video snippets. As the user pans the camera thru the physical space, the identified video snippets are overlaid in the location and direction at which they were originally tagged. Once the user stops panning, the FAST corner features of the current frame are matched with the tagged video snippet and the video overlay is adjusted to match the view and adjust that position of the overlay as the device moves in physical space.
This patent application describes the various approaches by which augmented reality systems are implemented and a hybrid mechanism to build a viable, practical augmented reality system which can run efficiently on a modem high end mobile device. The challenges in implementing a robust, scalable system are identified, and applicable solutions to overcome those issues are presented. The current work being done in hybrid techniques is extended by using a combination of markerless image processing techniques and location based information.
The techniques were tested by implementing a novel augmented reality application on the iPhone 4 which allows user to record, share and view user generated videos using an augmented reality interface. The popularity of websites such as YouTube and Facebook has made the creation and sharing of user generated videos mainstream. However the viewing and sharing of these videos have still been limited to the grids and lists of the traditional personal computer user interface. The “Looking Glass” tool presents an interface where the physical world around us is tagged with videos and allows users to see it by just focusing on it.
Further, the embodiments of the present invention enable the user to augment the physical real world environment with user generated videos. The augmented reality interface described makes video available based on location, enabling sharing and viewing videos across the physical space. By implementing an efficient algorithm on a mobile device, such an application could easily be embedded not only on mobile phones but other CE devices such as still and video cameras, and tablet devices. Such a system may provide value added features along with the photos, videos, and even live streams that may be tagged.
As used herein, the terms “a” or “an” shall mean one or more than one. The term “plurality” shall mean two or more than two. The term “another” is defined as a second or more. The terms “including” and/or “having” are open ended (e.g., comprising). Reference throughout this document to “one embodiment”, “certain embodiments”, “an embodiment” or similar term means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of such phrases in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner on one or more embodiments without limitation. The term “or” as used herein is to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B and C”. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.
In accordance with the practices of persons skilled in the art of computer programming, embodiments are described below with reference to operations that are performed by a computer system or a like electronic system. Such operations are sometimes referred to as being computer-executed. It will be appreciated that operations that are symbolically represented include the manipulation by a processor, such as a central processing unit, of electrical signals representing data bits and the maintenance of data bits at memory locations, such as in system memory, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to the data bits.
When implemented in software, the elements of the embodiments are essentially the code segments to perform the necessary tasks. The non-transitory code segments may be stored in a processor readable medium or computer readable medium, which may include any medium that may store or transfer information. Examples of such media include an electronic circuit, a semiconductor memory device, a read-only memory (ROM), a flash memory or other non-volatile memory, a floppy diskette, a CD-ROM, an optical disk, a hard disk, a fiber optic medium, etc. User input may include any combination of a keyboard, mouse, touch screen, voice command input, etc. User input may similarly be used to direct a browser application executing on a user's computing device to one or more network resources, such as web pages, from which computing resources may be accessed.
While the invention has been described in connection with specific examples and various embodiments, it should be readily understood by those skilled in the art that many modifications and adaptations of the augmented reality interface described herein are possible without departure from the spirit and scope of the invention as claimed hereinafter. Thus, it is to be clearly understood that this application is made only by way of example and not as a limitation on the scope of the invention claimed below. The description is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains. | A system, method, and computer program product for automatically combining computer-generated imagery with real-world imagery in a portable electronic device by retrieving, manipulating, and sharing relevant stored videos, preferably in real time. A video is captured with a hand-held device and stored. Metadata including the camera's physical location and orientation is appended to a data stream, along with user input. The server analyzes the data stream and further annotates the metadata, producing a searchable library of videos and metadata. Later, when a camera user generates a new data stream, the linked server analyzes it, identifies relevant material from the library, retrieves the material and tagged information, adjusts it for proper orientation, then renders and superimposes it onto the current camera view so the user views an augmented reality. | 6 |
INCORPORATION BY REFERENCE
[0001] The present application claims priority from Japanese application JP2007-031542 filed on Feb. 13, 2007, the content of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a software radio transceiver and, more particularly, to a software radio transceiver whose security performance has been improved.
[0004] 2. Description of the Related Art
[0005] In a software radio transceiver, software is changed, parameters are controlled, and a platform for making the software operative is used.
[0006] The platform has a role of separating a device and the software. As an example of the platforms, there is an operating system (OS) such as “Windows (registered trademark)”. By using such an OS as a platform, for example, even if a CPU (Central Processing Unit) device is either “Pentium (registered trademark)” or “AMD”, software such as “Word” or “Excel” can be used.
[0007] FIG. 8 shows an example of the platforms in the software radio transceiver.
[0008] Specifically speaking, modulation/demodulation software (hereinbelow, referred to as a MODEM software) 71 such as AM-16QAM or the like, middleware 72 , an OS 73 , a device driver 74 , and a CPU device 75 are provided for a modulating/demodulating unit (hereinbelow, referred to as a MODEM unit) 61 . The platform is constructed by the middleware 72 , OS 73 , and device driver 74 .
[0009] By the platform, dependency between the MODEM software 71 and the device (CPU device 75 ) can be separated and the MODEM software 71 can be executed irrespective of a device type. As mentioned above, in the software radio transceiver, the platform is necessary to enable the software to be exchanged.
[0010] As a platform of the software radio transceiver, for example, the OS such as “Linux” or “vxWorks” is used.
[0011] In such an OS, a security has to be considered. In the security, the OS has to be defended from a destruction or intrusion (for example, Trojan horse, or the like) which can make a capture/alteration of system information.
[0012] In the software radio transceiver, from a role as a communication apparatus, an encryption is necessary in order to avoid a leakage of data of communication information. In recent years, owing to a spread of an idea of the information security, it is interpreted that the encryption is also included in the security.
[0013] In the software radio transceiver, therefore, it is necessary to realize the two types of securities as mentioned above.
[0014] FIG. 9 shows an example of a threat to a software radio transceiver 81 .
[0015] In the software radio transceiver 81 , there are the following threats: an attacking/destroying action of a virus 83 which invades from a radio wave; an attacking/destroying action of a virus 84 which invades from a connected network 82 ; and a leakage of information due to a decipherment of a radio wave intercepted by another radio transceiver 85 . A security against such threats is necessary.
[0016] The above related art has been disclosed in, for example, JP-A-11-331911.
SUMMARY OF THE INVENTION
[0017] In the software radio transceiver in the related art, only an encryption has been performed. As a method of preventing the intrusion from the outside, for example, the following system is considered: an authenticating action of the radio communication path is performed on the assumption that a communication in which an identifier (ID) has been allocated to the radio communication path is made, and after a result indicative of an authentication of the authenticating action is obtained, the radio communication path having such an ID is connected. Such a system is often used in a wireless LAN (Local Area Network).
[0018] However, according to such a system, an area which cannot be defended in the communication path certainly exists.
[0019] FIG. 10 shows an example of a construction of the system of the wireless LAN.
[0020] The system of the example has: a radio router 91 ; an authentication server 92 ; a plurality of VLANs (Virtual LANs) 93 , 94 , and 95 ; a gateway (GATEWAY) 96 ; a network 97 ; and a plurality of personal computers (PCs) 101 , 102 , 103 , and 104 each having the function of the wireless LAN.
[0021] In the system of the example, the authentication server 92 defends an intrusion of a wireless LAN of a non-permitted PC. The gateway 96 defends an intrusion of a virus 113 from the network 97 . The radio router 91 defends an intrusion of a virus 112 from the network 97 . However, in the case where a virus 111 invades from the radio communication and attacks the radio router 91 , there are no precautions and an area which cannot be defended exists.
[0022] Therefore, for example, assuming that the authenticating action is performed by the authentication server 92 , an exchangeable function is necessary on the communication path from a point where a radio wave has been received to the authentication server 92 . If a platform exists there, there is such a problem that the intrusion of the virus to the platform is indispensable.
[0023] As mentioned above, in the software radio transceiver in the related art, a further improvement is requested in terms of the security.
[0024] The invention is made in consideration of such circumstances in the related art as mentioned above and it is an object of the invention to provide a software radio transceiver which can raise the security performance.
[0025] To accomplish the above object, according to the invention, in a software radio transceiver which can exchange software that is used for demodulation, the following construction is used.
[0026] That is, a radio communication unit receives a radio signal. A conversion unit converts the radio signal received by the radio communication unit into digital data. The transceiver has a plurality of demodulating units which demodulate sub-data. A dividing unit divides the digital data converted by the conversion unit into the sub-data and distributes the sub-data to the plurality of demodulating units. A connection unit connects results obtained from which each of the demodulating units demodulates the sub-data distributed to the plurality of demodulating units by the dividing unit.
[0027] Therefore, the digital data obtained from the received radio signal is divided into the sub-data and the sub-data is distributed to the plurality of demodulating units and each demodulating unit demodulates the divided sub-data (sub-data obtained after the division). Consequently, for example, even in the case where data of a virus is included in the received radio signal, each demodulating unit processes the data obtained by dividing the data of the virus (segmented data), so that a function as a virus can be invalidated. By connecting the demodulation results (sub-data obtained after the demodulation) of the demodulating units, demodulation results of the original order can be obtained. Although there is a possibility that the demodulation results of the original order becomes the data of the virus, such virus data can be found out and exterminated by, for example, a processing unit provided at the post stage (for example, security unit 12 shown in FIG. 1 ).
[0028] In this manner, security performance in the software radio transceiver can be improved.
[0029] The number of plurality of demodulating units can be set to an arbitrary number. For example, the two demodulating units can be used or three or more demodulating units may be used.
[0030] As a construction of dividing the digital data into the sub-data and distributing them to the plurality of demodulating units, various constructions can be used. For example, a construction in which the digital data is divided into the sub-data at the same period and the sub-data is periodically distributed to each of the plurality of demodulating units can be also used.
[0031] As described above, according to the software radio transceiver of the invention, the digital data obtained from the received radio signal is divided into the sub-data and the sub-data is distributed to the plurality of different demodulating units and demodulated. Therefore, for example, even in the case where the virus is included in the received radio signal, the virus can be invalidated in the demodulating units and the security performance in the software radio transceiver can be improved.
[0032] Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a diagram showing a constructional example of a software radio transceiver according to an embodiment of the invention;
[0034] FIG. 2 is a diagram showing an example of a platform of a MODEM unit;
[0035] FIG. 3 is a diagram showing an example of an attack of a virus to the platform of the MODEM unit;
[0036] FIG. 4 is a diagram showing a constructional example of the MODEM unit according to the embodiment of the invention;
[0037] FIG. 5 is a diagram showing an example of a flow of received code data;
[0038] FIG. 6 is a diagram showing an example of a demodulation and a connection of the code data;
[0039] FIG. 7 is a diagram showing an example of a protection of the platform according to segmentation of the virus;
[0040] FIG. 8 is a diagram for explaining necessity of a platform in software radio transceiver;
[0041] FIG. 9 is a diagram for explaining necessity of a security in the software radio transceiver; and
[0042] FIG. 10 is a diagram for explaining vulnerability to the virus in a wireless LAN.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0043] An embodiment according to the invention will be explained with reference to the drawings.
[0044] FIG. 1 is a diagram showing a constructional example of a software radio transceiver 1 according to the embodiment of the invention.
[0045] The software radio transceiver 1 of the embodiment has a MODEM (modulating/demodulating) unit 11 , a security unit 12 , and an interface unit (I/F unit) 13 .
[0046] The security unit 12 has, for example, an authentication server/client 21 and an encryptor 22 as a construction similar to that in the case of the wireless LAN.
[0047] In the software radio transceiver 1 of the embodiment, an audio signal inputted from a microphone is inputted to the MODEM unit 11 through the I/F unit 13 and the security unit 12 , modulated by the MODEM unit 11 , and transmitted from an antenna 41 in a wireless manner. A radio signal received by the antenna 41 is demodulated by the MODEM unit 11 and, thereafter, outputted as an audio sound from a speaker through the security unit 12 and the I/F unit 13 .
[0048] The software radio transceiver 1 of the embodiment may be connected to, for example, an external network.
[0049] The intrusion of a virus from the network can be prevented by executing and making operative software for precautions against viruses (anti-virus software) on platforms of the I/F unit 13 and the security unit 12 . For example, for the intrusion from the network, invasion protective wall software is executed on the platform of the I/F unit 13 and port scan monitoring can be executed. Even if a virus invaded, software which can instantaneously find out and exterminate the virus can be executed on the platform of the security unit 12 .
[0050] However, if a virus invaded in a wireless manner, a type of code data cannot be discriminated until a radio wave is demodulated and the code data is obtained, so that the invasion protective wall (fire wall) cannot be used. That is, since the invasion protective wall is built in the software radio transceiver 1 , there is no meaning of the security. In the MODEM unit 11 , in many cases, since there is no room for execution of software which can instantaneously find out and exterminate the virus, if the code data is virus software, there are no measures for stopping the execution of the virus.
[0051] FIG. 2 shows an example of the platform of the MODEM unit 11 .
[0052] Modulation/demodulation software (MODEM software) 31 such as AM-16QAM or the like, middleware 32 , an operating system (OS) 33 , and a CPU device 34 are provided for the MODEM unit 11 of the embodiment. In the embodiment, the platform is constructed by the middleware 32 and the OS 33 . The MODEM software 31 can be exchanged by this platform.
[0053] However, as shown in FIG. 3 , the MODEM software 31 and the platform are subjected to a danger by an attack/destroy of a virus 35 .
[0054] In the software radio transceiver 1 of the embodiment, a construction to realize a security for defending an area of the MODEM unit 11 against a virus which invades in a wireless manner is provided as a construction to take a countermeasure against a threat of the virus to the MODEM unit 11 .
[0055] FIG. 4 shows a constructional example of the MODEM unit 11 of the embodiment.
[0056] The MODEM unit 11 of the embodiment has: the antenna 41 ; a power amplifying unit 42 ; a frequency conversion unit 43 ; a conversion unit 44 having an A/D (Analog to Digital) converter and a D/A (Digital to Analog) converter; a clock generating unit 45 ; a switch unit 46 ; a first modulating/demodulating (MODEM) unit 47 ; a second modulating/demodulating (MODEM) unit 48 ; a code connection unit 49 ; and an encryption unit interface (I/F) unit 50 .
[0057] A platform exists in each of the MODEM units 47 and 48 . By downloading software of this platform through a predetermined interface, the software which is used for modulation/demodulation can be exchanged.
[0058] In the embodiment, the same software is downloaded into the two MODEM units 47 and 48 and used.
[0059] An example of the operation which is executed in the MODEM unit 11 of the embodiment is shown.
[0060] A receiving process will be described.
[0061] The radio signal received by the antenna 41 is amplified by the power amplifying unit (for example, low noise amplifier) 42 , converted from a radio frequency (RF) into an intermediate frequency (IF) by the frequency conversion unit 43 , and converted from an analog signal into digital code data by the A/D converter in the conversion unit 44 .
[0062] The clock generating unit 45 generates a clock signal having a predetermined period and outputs to the switch unit 46 and the two MODEM units 47 and 48 .
[0063] The switch unit 46 has a switch for switching a path by an interruption of the clock signal generated from the clock generating unit 45 . In the embodiment, each time there is an interruption of the clock signal, the switch unit 46 switches a state of the path for outputting the code data from the conversion unit 44 to the first MODEM unit 47 and a state of the path for outputting the code data from the conversion unit 44 to the second MODEM unit 48 . Thus, the code data from the conversion unit 44 is distributed to the first MODEM unit 47 and the second MODEM unit 48 .
[0064] On the basis of the clock signal inputted from the clock generating unit 45 , each of the MODEM units 47 and 48 demodulates the inputted code data and outputs its demodulation result (code data obtained after the demodulation) to the code connection unit 49 in response to the timing when the code data is inputted from the switch unit 46 .
[0065] The code connection unit 49 connects the code data which is obtained after the demodulation and inputted from the two MODEM units 47 and 48 at the alternating timing so that the code data is arranged in the original order, and outputs its connection result (reception signal obtained after the demodulation) to the encryption unit I/F unit 50 .
[0066] The encryption unit I/F unit 50 has a function for inputting and outputting analog and/or digital data from/to the outside (in the embodiment, security unit 12 ) and outputs the reception signal inputted from the code connection unit 49 to the outside (in the embodiment, security unit 12 ).
[0067] FIG. 5 shows an example of a state of a flow of the received code data with respect to the two MODEM units 47 and 48 and its peripheral processing units.
[0068] The code data which is inputted by switching the first MODEM unit 47 and the second MODEM unit 48 , that is, the code data which is distributed to the first MODEM unit 47 and the second MODEM unit 48 is the data having the same length because the clock signals have the same period.
[0069] Each of the MODEM units 47 and 48 repeats the execution and stop (sleep) of the demodulating process synchronously with the clock period by the interruption of the clock signal from the clock generating unit 45 . That is, while the code data is being inputted, each of the MODEM units 47 and 48 executes the demodulation. When no code data is inputted (for a period of time from the completion of a certain demodulating process to the start of the next demodulating process), each of the MODEM units 47 and 48 stops the demodulation.
[0070] The code connection unit 49 connects the code data demodulated by the two MODEM units 47 and 48 and returns them to one reception signal.
[0071] FIG. 6 shows an example of the states of the demodulation and the connection of the code data.
[0072] In the two MODEM units 47 and 48 , the timing when the demodulating process is executed and the timing when the demodulating process is stopped are opposite, so that the demodulation is alternately executed.
[0073] In the code connection unit 49 , the demodulated code data which is inputted from the two MODEM units 47 and 48 at the alternate timing is connected to one data.
[0074] FIG. 7 shows an example of a state of protection of the platforms which is realized by segmentation of a virus with respect to the two MODEM units 47 and 48 and its peripheral processing units.
[0075] Even in the case where software of a virus 51 which invades in a wireless manner is included in the reception signal, code data obtained from this reception signal is divided into two sub-data, and the two sub-data are inputted to each of the MODEM units 47 and 48 . Therefore, in the code data inputted to each of the MODEM units 47 and 48 , sub-data (segments of the virus) 52 and 53 obtained by segmenting the code data of the virus 51 are subjected to the demodulating process. Thus, the code data of the virus cannot operate as a virus on the platforms. In the code data connected by the code connection unit 49 (demodulated reception signal), software of a virus 54 (corresponding to the foregoing virus 51 ) revives. However, since it is exterminated by the security unit 12 provided just after the MODEM unit 11 , the security is assured.
[0076] As mentioned above, in the platforms existing in the MODEM units 47 and 48 , since the segment sub-data of the virus is handled, the segment cannot show a function as a virus and the platforms can be protected against the attack/destroy that is performed by the virus. There is a possibility that the data connected by the code connection unit 49 is data of the virus. However, since the code connection unit 49 and the encryption unit I/F unit 50 are hardware having no platform, the virus is not executed but sent to the security unit 12 and exterminated there. Consequently, the platform of the MODEM unit 11 of the software radio transceiver 1 which is threatened with the virus can be protected.
[0077] A transmitting process will now be described.
[0078] Data inputted from the outside (in the embodiment, security unit 12 ) through the encryption unit I/F unit 50 is inputted to the MODEM units 47 and 48 through the code connection unit 49 , modulated by the MODEM units 47 and 48 , and inputted to the conversion unit 44 through the switch unit 46 . The data inputted to the conversion unit 44 is converted from the digital signal into the analog signal by the D/A converter in the conversion unit 44 , converted from the intermediate frequency (IF) into the radio frequency (RF) by the frequency conversion unit 43 , amplified by the power amplifying unit 42 , and transmitted from the antenna 41 in a wireless manner.
[0079] In the transmitting process, it is not always necessary to use both of the two MODEM units 47 and 48 . For instance, it is also possible to construct in such a manner that no processes are executed in particular in the code connection unit 49 , the switch of the switch unit 46 is connected to one of the two MODEM units 47 and 48 , and the modulation is executed by using only the connected MODEM unit.
[0080] In the transmitting process, the two MODEM units 47 and 48 can be also alternately used in a manner similar to that in the receiving process. For example, it is also possible to construct in such a manner that the data from the encryption unit I/F unit 50 is divided into two sub-data by the code connection unit 49 , the two sub-data are alternately inputted to the two MODEM units 47 and 48 , the switch is switched so that the switch unit 46 is alternately connected to the paths of the two MODEM units 47 and 48 , and the data of the original order (data obtained after the modulation) is inputted to the conversion unit 44 .
[0081] As another constructional example, the processing unit for executing the transmitting process and the processing unit for executing the receiving process can be also provided as individual processing units with respect to all or a part of them.
[0082] As mentioned above, in the software radio transceiver 1 of the embodiment, a binary code of the virus is segmented in the MODEM unit 11 against the virus which invades in a wireless manner, so that the function of the virus can be invalidated and an intrusion by an external hacker/cracker or the like can be prevented.
[0083] Therefore, in the software radio transceiver 1 of the embodiment, the software radio transceiver can be protected from the virus, a defense method which can cope with any type of virus is not limited can be provided, and a defense method which can be applied to the general software radio communication can be provided. According to the construction of the embodiment, for example, although there is a possibility that the hardware enlarges (as compared with the case of using only one MODEM unit), since there is no need to form the software for precautions against viruses, labor costs and the like can be consequently reduced.
[0084] In the software radio transceiver 1 of the embodiment, a radio communication unit is constructed by the function of receiving the radio signal by the antenna 41 , power amplifying unit 42 , and frequency conversion unit 43 , a conversion unit is constructed by the function of converting the reception signal into the digital data by the A/D converter in the conversion unit 44 , a plurality of demodulating units are constructed by the demodulating functions of the plurality of MODEM units 47 and 48 , a dividing unit is constructed by the function of dividing the digital data by the clock generating unit 45 and the switch unit 46 and distributing the sub-data to the plurality of demodulating units 47 and 48 , and a connection unit is constructed by the function of connecting the demodulation results obtained from the plurality of demodulating units 47 and 48 by the code connection unit 49 .
[0085] The constructions of the system, apparatus, and the like according to the invention are not always limited to those mentioned above but various constructions can be used. The invention can be also provided, for example, as a method or system for executing the processes according to the invention, a program for realizing such a method or system, a recording medium for recording such a program, or the like. The invention can be also provided as various systems or apparatuses.
[0086] Fields of application of the invention are not always limited to those mentioned above but the invention can be also applied to other various fields. For example, the construction shown in the above embodiment can be applied to not only the software radio transceiver but also a general radio transceiver.
[0087] As various processes which are executed in the system, apparatus, and the like according to the invention, a construction in which the system, apparatus, and the like are controlled by a method whereby a processor executes a control program stored in a ROM (Read Only Memory) in a hardware resource having the processor, a memory, and the like can be used. For example, each of the function units for executing the processes can be also constructed as an independent hardware circuit.
[0088] The invention can be also grasped as a computer-readable recording medium such as floppy (registered trademark) disk, CD (Compact Disc)-ROM, or the like in which the foregoing control program has been stored or as such a program (itself). The processes according to the invention can be also executed by a method whereby the control program is inputted from the recording medium to the computer and executed by the processor.
[0089] It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modification may be made without departing from the spirit of the invention and the scope of the appended claims. | Security performance is improved by a software radio transceiver which can exchange software which is used for demodulation. A radio communication unit receives a radio signal. A conversion unit converts the radio signal received by the radio communication unit into digital data. The transceiver has a plurality of demodulating units which demodulate sub-data. A dividing unit divides the digital data converted by the conversion unit and distributes the sub-data to the plurality of demodulating units. A connection unit connects results obtained after the sub-data divided and distributed to the plurality of demodulating units by the dividing unit was demodulated by each of the demodulating units. | 7 |
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/666,754 filed Mar. 30, 2005.
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT
[0002] (Not Applicable)
REFERENCE TO AN APPENDIX
[0003] (Not Applicable)
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates generally to aerodynamic devices for vehicles, such as automobiles, trucks, airplanes, jets, and any other vehicles that move through air.
[0006] 2. Description of the Related Art
[0007] It is known in the field of aerodynamics that “dead spaces” exist behind vehicles that move through air, and such dead spaces contain drag-increasing negative air pressures behind them. Existing devices, such as wings, are used to drive air into dead spaces in order to reduce the drag on the vehicle. As the vehicle moves through the air, the wing directs air into the dead spaces to reduce this negative pressure.
[0008] Wings and other aerodynamic devices are typically stationary, inasmuch as they do not move as the vehicle is moving. Some devices can move as the vehicle is moving, but such devices only move due to their attachment to a part of the vehicle that move, such as suspension components. Thus, as the suspension components move relative to the vehicle body, the aerodynamic device moves. However, this movement is very limited, and is not controlled by wind speed, but suspension movement or some other factor not related to the aerodynamic impact that the device is intended to affect. Alternative devices include wings that raise and lower according to speed of the vehicle, so that as the vehicle's speed increases, the wing rises to produce more downwardly-directed force to stabilize the vehicle.
[0009] Wings and other aerodynamic devices have disadvantages. Therefore, the need exists for devices that reduce the negative air pressure in dead spaces and otherwise affect the aerodynamic effects, such as by increasing drag, without the attendant disadvantages of wings.
BRIEF SUMMARY OF THE INVENTION
[0010] The invention is an aerodynamic apparatus mounted to a vehicle having a vehicle body over which air flow passes during motion of the vehicle. The apparatus comprises a roller rotatably mounted about its axis to the vehicle body and having a radially outwardly facing surface. The radially outwardly facing surface of the roller is disposed near an edge of the vehicle body over which the air flow passes during motion of the vehicle. This permits air that flows over the roller to tend to rotate the roller. Upon rotation, the roller affects the aerodynamic properties of the vehicle.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is a side schematic view illustrating a conventional box truck on which an embodiment of the invention is mounted.
[0012] FIG. 2 is a view in perspective illustrating a close-up view of the invention on the FIG. 1 truck.
[0013] FIG. 3 is a view in perspective illustrating the roller of the FIG. 1 embodiment.
[0014] FIG. 4 is a view in perspective illustrating an alternative embodiment of the present invention.
[0015] In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or term similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The truck 8 in FIG. 1 has a cargo box 10 mounted on a frame, and a cab 12 , as is well known. As the truck moves through the air, it forces the air beside it, above it and below it. That air is pressurized locally due to its displacement by the truck body, and as the truck moves through the air, the air passes back around the rear thereof. However, because the rear of the conventional truck box 10 has an abrupt transition, the air passes over the back edge 20 of the box 10 , rather than conforming exactly to the trailing surface of the box 10 , and would create a low pressure area just below the back edge 20 if it were not for the invention, which will now be described.
[0017] A roller 30 is rotatably mounted to the box 10 with the axis of the roller 30 substantially parallel to the back edge 20 . The roller 30 extends almost the entire width of the box 10 , although the length of the structure can vary, as discussed below. The roller 30 is preferably a circular cylinder made of a lightweight material, such as hollow aluminum, plastic, composite (e.g., fiberglass or carbon fiber) or any other material that will suffice, as will be understood by a person having ordinary skill in the art from the description herein.
[0018] The roller 30 is mounted to the box 10 by a pair of mounting legs 32 and 34 at opposite ends of the roller 30 (mount 34 is not shown). The legs 32 and 34 are substantial mirror images of one another, and function to mount the roller 30 securely to the body to which it is attached. For example, the legs 32 and 34 can be made of lightweight aluminum, and can mount with flanges at the end seating against the box 10 . The ends of the legs that attach to the roller 30 preferably insert into a low-friction ball-bearing assembly 36 , shown in FIG. 3 . The ball-bearing assembly is conventional and can be press-fit into an aperture at each end of the roller 30 , preferably aligned coaxially with the axis of the roller 30 . Thus, the roller 30 is mounted to the box 10 so that it can rotate freely about its axis, but will not detach from the vehicle until deliberately removed, such as for maintenance or replacement.
[0019] The roller 30 is mounted with its radially outwardly facing surface 38 to near a plane that contains the roof 16 of the box 10 . The surface 38 can be aligned precisely along the plane, thereby aligning the plane along a tangent of the surface 38 , or it can be raised above it or below it. In all cases, however, the surface 38 is aligned along the path of air that flows over the vehicle body, such as the roof 16 , so that at least some of the molecules of air moving over the body impinge more upon one half of the surface 38 than the opposite half. This impingement of the molecules on the surface 38 causes the roller 30 to rotate about its axis. The volume of air molecules that impinge upon the surface 38 , the speed of the air and other factors, which will become apparent to the person having ordinary skill from this description, will affect the acceleration of and the velocity of the roller 30 .
[0020] As the roller 30 rotates, it attains a desired speed, which is preferably equal to, greater than or less than, the speed of the air passing over the vehicle body just upstream of the roller 30 . When the surface 38 rotates substantially the same speed as the air, the resistance that the rotating surface 38 presents to air molecules passing over the box 10 is less than the air molecules would encounter if there was no roller. This is due to the fact that the surface 38 is moving faster than a stationary object. Additionally, the curvature of the roller 30 more gradually directs air around the box 10 . Finally, and very importantly, because the roller 30 is rotating, its outer surface 38 tends to force air behind the box 10 where negative pressure otherwise exists in conventional trucks of the same shape as the truck 8 (without the invention attached thereto).
[0021] In a preferred embodiment, the roller 30 has dimples 39 or concave depressions of any other kind, including elongated concave depressions, such as slots, formed in the curved surface 38 in order to increase the friction between the surface 38 and air molecules passing over the surface 38 . The dimples 39 thus function in the manner of dimples on the outer surface of a conventional golf ball. As another alternative, the roller could have convex bumps that protrude out of the surface of the roller.
[0022] In addition to the roller 30 on the top edge of the box 10 , the roller 40 is preferably mounted to the side edge of the box 10 . The roller 40 is mounted in a manner similar to the roller 30 , but at the side edge of the box 10 , rather than the top edge 20 . Other rollers can be mounted on the other edges of the box 10 , including the bottom and the leading edges, as will be apparent to the person having ordinary skill in the art.
[0023] Thus, the invention is a roller mounted on bearings so that it can rotate very freely. The goal of the invention is to improve the aerodynamic effects of the object moving through the air. In order to achieve that goal, a plurality of such rollers can be strategically mounted on any vehicle trying to move through the air efficiently, including, but not limited to, an automobile, truck, tractor-trailer, train, motorcycle, bicycle or airplane. Rollers are positioned near edges of the vehicles' bodies around which air rushes when the vehicle is in motion, and more of one part of the rollers are exposed to air rushing over the edge of the body than the other. The air causes the rollers to rotate about their axes as more air passes over one edge of the roller than the other.
[0024] The rollers force air into “dead spaces” behind vehicles that otherwise contain drag-increasing negative air pressures. When left to rotate freely, the rollers, as dictated by the laws of physics, tend to rotate at the most efficient speed to reduce drag by filling the negative pressure zones with air, thus reducing the drag on the vehicle. The rollers thus effectively alter the aerodynamic “shape” of the object they are attached to. The rollers adjust their rotating speed to the optimum level to reduce wind resistance. The spinning rollers alter the airflow and improve aerodynamic efficiency.
[0025] The rotation of the rollers can also be controlled to alter their aerodynamic effects to suit certain situations, such as by attaching a motor 50 , as in FIG. 4 , or brakes to the rollers. The driveshaft of the motor 50 is mounted to the roller 60 either by a rigid connection, or by a “coasting” device, similar to that in a bicycle hub, that prevents the motor 50 from resisting movement of the roller 60 in one direction when such resistance is not desired, but provides a drive link to the roller 60 in the other direction.
[0026] The rollers can thus be artificially slowed to generate drag, thereby slowing a vehicle, or the rollers' speeds can be increased beyond that due to the flow of air in order to generate less drag or more lift, such as for a wing, thereby utilizing an energy source to induce certain effects. Of course, with multiple rollers, different rollers can be affected differently in order to best accomplish the desired result, as in an automobile in which the brakes, accelerator and the rollers of the invention are controlled by a vehicle's stability control system.
[0027] The roller need not be a circular cylinder. The roller could be octagonal or any other polygonal cylinder. Alternatively, the roller could have a larger diameter in the middle than at the ends, or could be larger at one end than the opposite end, such as with a cone or other tapered shape, as will become apparent to a person having ordinary skill in the art. This allows the roller to be tailored to the particular structure to which it is mounted.
[0028] Still further, the roller can be made up of multiple disks or rotatably-mounted polygons “stacked” together with aligned axes in order to affect airflow around a vehicle. This would permit rotation of one disk relative to another.
[0029] While certain preferred embodiments of the present invention have been disclosed in detail, it is to be understood that various modifications may be adopted without departing from the spirit of the invention or scope of the following claims. | An aerodynamic aid for vehicles, including automobiles, trucks, trains, airplanes and motorcycles. A cylindrical roller is rotatably mounted in the path of airflow over the vehicle's body. When the air begins to flow, the roller rotates and causes air resistance of the vehicle to change. The roller can increase or decrease air flow through spaces where there is negative pressure. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to automatic article sorting apparatus and, more particularly, to such apparatus adapted for sorting laundered articles according to their lengths.
2. Description of the Prior Art
My prior U.S. Pat. No. 3,467,138, issued Aug. 19, 1969, discloses apparatus for automatically folding laundered articles of various sizes, such apparatus being particularly adapted for commercial or institutional use where large quantities of articles are laundered. Clean, unfolded articles of mixed sizes are sequentially fed into one portion of the apparatus and the articles in a folded condition are dispensed from another portion of the machine onto a receiving table or conveyor. However, the apparatus does not provide means for sorting the articles in any manner, the folded articles being dispensed in the same order as they were fed into the apparatus.
While such an automatic folding apparatus has been commercially successful and has provided substantial cost savings by eliminating the labor previously required to fold large quantities of laundered articles, time is still required either to manually sort articles fed into the apparatus, or to manually sort articles dispensed from the apparatus, into appropriate size categories such as wash cloths, hand towels, bath towels, pillow cases and sheets.
To applicant's knowledge, no practical apparatus is available which will automatically sort such laundered articles, either before or after folding, into preselected categories such as size, or which will allow such sorting on a selective basis, that is, which will allow an operator to cause selected articles to by-pass the sorting apparatus and proceed to a common discharging portion, such as sometimes may be necessary or desired for various reasons.
SUMMARY OF THE INVENTION
An automatic article sorting apparatus, in accordance with the invention, comprises a plurality of series-arranged article conveyor assemblies having associated therewith a plurality of article receiving assemblies. Discharging means are provided for selectively discharging sorted articles from each of the conveyor assemblies to their associated receiving assembly. Sorting means are provided which are adapted for sorting articles conveyed by the conveyor assemblies according to at least one preselected article parameter and cooperating with the discharging means to cause articles having substantially different values of the preselected parameter to be automatically discharged from different ones of the conveyor assemblies. The sorting means includes means for momentarily stopping a conveyor assembly while an element is being discharged therefrom. Bypass means may be provided for selectively allowing an article to proceed, through previous ones of the conveyor assemblies, to a preselected one of the conveyor assemblies for discharging therefrom, regardless of the value of the article's preselected parameter.
More particularly, sorting of articles is provided according to their length; and the sorting means may provide either for discharging articles of progressively shorter or of progressively longer length from sequential ones of the conveyor assemblies. The discharging means includes a pair of pivotal discharging blades associated with each of the conveyor assemblies. In a similar manner, the sorting means includes a plurality of individual sorting means, one said individual sorting means being associated with each of the conveyor assemblies.
At least some of the individual sorting means include a fixed switch, which is operated by an article passing thereby, and an associated presettable timing element. The length of time required for an article to be conveyed past the fixed switch is electically compared to the preset time on the timing element and an article is automatically caused to be discharged by pivoting the associated discharging blades when the actual passing time exceeds the preselected time. Successive individual sorting means have timers preset to successfully shorter preselected times to cause successively shorter articles to be discharged.
In combination with a laundered article folding machine, three conveyors and associated discharging assemblies, receiving assembly and individual sorting means are employed. The first two of the individual sorting means are provided with timing elements preset respectively, at the first and second preselected times. The third sorting means provides for only discharging all articles which bypass the first two individual sorting means. All three individual sorting means however provide for a momentary stopping of conveyor belt of the conveyors when an article is being discharged therefrom so that the falling article does not overshoot the associated receiving assembly.
The three conveyors and associated discharging and receiving assemblies, may be of different lengths and be arranged in order of decreasing length. If means are provided for causing articles to bypass the first two discharging assemblies, however, the third conveyor and associated discharging and receiving assemblies are constructed to be the same length as the first, unless provision is made for also bypassing the third discharging means and discharging articles out the end of the apparatus.
The sorting means are easily adaptable to sort on the basis of article parameters other than length. For example, photodetectors may be provided, in place of the switches and timing elements, to detect differences in article surface reflectivity, whereby articles may be sorted according to their color or material from which they are fabricated.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention may be had from a consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view, partially broken away, of article sorting apparatus in accordance with the present invention, shown integrally connected to an article folding apparatus;
FIG. 2 is a vertical sectional view of the article sorting apparatus of FIG. 1;
FIG. 3 is a bottom view along line 3--3 of FIG. 1 showing an article advancing across the first sorting station;
FIG. 4 is a vertical sectional view, along line 4--4 of FIG. 2, showing the article discharging blades of the first sorting station in a condition for advancing an article;
FIG. 5 is a vertical view along the plane of FIG. 4, showing the article discharging blades of the first sorting station in a condition for discharging an article;
FIG. 6 is a sectional view, along line 6--6 of FIG. 3, showing a typical conveyor roller brake means;
FIG. 7 is an electrical schematic of the article sorting controls of the apparatus of FIG. 1: FIG. 7A depicting the controls for the first sorting station, FIG. 7B depicting the controls for the second sorting station and FIG. 7C depicting the controls for the third sorting station; and
FIG. 8 is an electrical schematic of the sorting bypass system of the apparatus of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An automatic article sorting apparatus 10, for sorting folded laundry articles, is connected, as best seen in FIG. 1, in article receiving relationship with a laundry folding apparatus 12 to form a composite laundry folding and sorting machine 14. The folding apparatus 12, which is disclosed in my prior U.S. Pat. No. 3,462,158 forms no part of my present invention.
As more particularly described below, the article sorting apparatus 10, which sorts articles according to their lengths, comprises generally a plurality (three being shown) of substantially identical and series or tandem arranged sorting stations: a first sorting station 16, a second sorting station 18 and a third sorting station 20 (FIGS. 1-3). The first sorting station 16 comprises a first conveyor belt assembly 22 and first discharging assembly 24 with a first receiving assembly 26 disposed therebelow. Similarly, the second sorting station 18 comprises a second conveyor belt assembly 30, a second discharging assembly 32 and a second receiving assembly 34, and the third sorting station 20 comprises a third conveyor belt assembly 36, a third discharging assembly 38 and a third receiving assembly 40. Associated with the first two sorting stations 16 and 18 are means for comparing the lengths of articles passing along the respective conveyor belt assemblies 22 and 30 to first and second predetermined lengths. If the first predetermined length of an article is not reached in the first sorting station 16, the article is passed to the second sorting station 18. If the second predetermined length for the second sorting station is not reached, the article is passed to the third sorting station. Transfer of articles from one sorting station to the next is facilitated by a first flat guideway member 42 disposed between and below adjacent portions of the first and second conveyor assemblies 22 and 30, and a second flat guideway member similarly disposed between the second and third conveyor assemblies 30 and 36.
More particularly described, the first conveyor belt assembly 22 comprises two horizontally spaced belt support rollers: a forward (in respect to the laundry folding apparatus 12) roller 50 and a rear roller 52, both of which are mounted transversely to the longitudinal axis of the sorting apparatus 10 and which are rotatably supported upon shafts 54 and 56, respectively, in side walls 58 and 60 which form rearward exteriors of sides of the folding apparatus. Mounted upon the rollers 50 and 52 are two laterally spaced, flexible conveyor belts 62 and 64 (FIGS. 1 and 3). The forward roller 50 is driven in a counterclockwise direction (the direction of arrow A in FIGS. 1 and 2) by means of a sprocket 66 which is mounted upon the shaft 54 and which is driven from portions (not shown) of the folding apparatus 12 by a drive chain 68. Lower portions of the belts 58 and 60 are thereby caused to be driven rearwardly (in the direction of arrow B, FIG. 2) to cause an article 70, delivered to the first sorting station 16 by a conveyor (not shown) at the article folding apparatus 12, to be advanced rearwardly towards the second and third sorting stations 18 and 20 between such belts and the first discharging assembly 24 which is disposed immediately therebelow.
In a similar manner, the second conveyor assembly comprises a forward roller 74 and a rearward roller 76 mounted upon shafts 78 and 80 respectively, which are pivotably mounted in the walls 58 and 60, the roller 74 being comparatively close to the roller 52. Two laterally spaced conveyor belts 82 and 84 are mounted on the rollers 74 and 76. The forward roller 74 is also driven in a counterclockwise direction (direction of arrow C, FIG. 2) by a chain 86 which passes over a sprocket 88 fixed to the shaft 78 (FIG. 3). Likewise, the third conveyor assembly comprises a forward roller 94 (positioned adjacent to the roller 76) and a rear roller 96 journalled for rotation in walls 58 and 60 upon shafts 98 and 100 respectively. Spaced conveyor belts 102 and 104 are mounted upon the rollers 94 and 96. The roller 94 is driven, through a sprocket 106 mounted on shaft 98 and by a chain 108, to cause such roller to rotate in a counterclockwise direction (direction of arrow D, FIG. 2).
The discharging assembly 24, as seen in FIG. 4, comprises an opposing pair of shaped flipper blades 110 and 112 which have, in the normal article conveying configuration shown, flat horizontal portions 114 and 116 respectively, upon upper surfaces of which articles are conveyed, driven by the belts 62 and 64. The blades 110 and 112 also have generally vertical side portions 118 and 120, respectively which curve upwardly around under portions of the belts 62 and 64, between the rollers 50 and 52, and are pivotably mounted to structure not shown, at upper edges of such side portions by shafts 122 and 124, respectively. Operating arms 126 and 128 are affixed to upper edges of the blade sides 118 and 120, respectively, being directed generally outwardly. Pivotably mounted to the free arm 126 is a push rod 130 which is connected to a pneumatic cylinder 132, operation of which is controlled by a solenoid valve 134 connected thereto. An upper end of the cylinder 132 is pivotably mounted to a bracket 138 which projects inwardly from the side wall 60. For operation of the blade 112, one end of a link 140 is also pivotably mounted to the free end of the arm 126. The other end of the link 140 is connected to a bar 142 which is pivotably connected at an upper end to a bracket 144 fastened to the inside of the side wall 58. A link 146 is pivotably connected at one end to a lower portion of the bar 142 and its other end to the free end of the arm 126 affixed to the blade 112.
Assembled in a similar manner (and therefore not illustrated or described in detail) are similar flipper blades 148 and 150 of the second discharging assembly 32 and corresponding blades 152 and 154 of the third discharging assembly 38 (FIG. 3).
A roller brake assembly 158 is provided whereby the conveyor belt assembly 22 may be stopped, as more fully described below, when articles are discharged therefrom. The brake assembly 158, illustrated in FIG. 6, comprises a roller brake member 160 having a lower arcuate roller-contacting portion 162 and having a transverse upper arm portion 164. One end of the arm portion 164 is pivotably mounted to the inside of the wall 60 by a bolt 166. To the other end of the arm 164 is pivotably connected an actuating piston 168 of a pneumatic cylinder 170. The upper end of the cylinder 170 is mounted to the wall 60 by a bolt 172. Operation of the cylinder 170 is controlled by a solenoid valve 174 which is connected thereto. Similar brake assemblies 176 and 178 are mounted adjacent to the roller 74 of the second conveyor belt assembly 30 and the roller 94 of the third conveyor belt assembly 36, respectively (FIG. 3).
The first, second and third receiving assemblies 26, 34 and 40 comprise generally conventional conveyor belts 180, 182 and 184 mounted upon pairs of roller conventionally driven, in a manner not shown, in the direction of the arrows E in FIG. 1. Such receiving assemblies may be similar to those described in my prior U.S. Pat. No. 3,462,138 (incorporated herein by reference) and may be such that the conveyor belts are vertically spring-biased so that they are automatically depressed downwardly by the weight of articles received thereupon, so that articles may be received in stacked form upon the conveyor when it is not being operated.
To enable sorting articles received from the folding apparatus 12, according to the length of such articles, electrical means are provided for comparing the length of articles conveyed upon each of the first two conveyor assemblies 22 and 30 with the first and second preselected lengths respectively, and for causing actuation of the first or second discharging assemblies 24 or 32, respectively, according to whether the length of the article is longer than the first preselected length, in which case it will be caused to be discharged through the first discharging assembly, or whether the article is shorter than the first preselected length but longer than the second preselected length, in which case it will be caused to be discharged through the second discharging assembly. If an article is shorter than both the first and second preselected lengths, neither of the discharging assemblies 24, 32 will be actuated and the article will be advanced to the third conveyor assembly 36, where it will be caused to be discharged through the third discharging assembly 38 and onto the third receiving assembly 40.
To these ends, first and second, normally open Microswitches 190 and 192 are positioned in closely spaced relationship between the belts 62 and 64 of the first conveyor assembly 22, and in locations near the receiving end of such conveyor assembly, the switch 190 being slightly closer to the folding apparatus 12 than is the switch 192. Switch actuating rods or levers 194 and 196 of the switches 190 and 192, respectively, project vertically downwardly between the belts 62 and 64 and the discharging blades 110 and 112, so that the rods will be contacted by a leading edge 198 of an article 70 passing rearwardly between the belts and the blades, and thereby cause actuation of the associated switches. Associated circuitry, depicted schematically in FIG. 7A, includes a conventional timing element 200 and a conventional delaying element 202, operation of which is more particularly described below.
Two normally open Microswitches 204 and 206 are similarly positioned near the forward end of the second conveyor 30, the switch 204 being positioned more forwardly than the switch 206. Actuating rods 208 and 210 of switches 204 and 206, respectively, project downwardly between the conveyor belts 82 and 84 and the associated blades 148 and 150 so that they may be contacted by the article leading edge 198 to close the switches. Associated circuitry, depicted in FIG. 7B, includes a conventional timing element 212 and a conventional time delay element 214, more fully described below.
In the third conveyor assembly 36, only a single normally open Microswitch 216, having an actuating rod or lever 218 projecting downwardly between the conveyor belts 102 and 104 and the blades 152 and 154, is employed. The switch 216 is positioned to be near the rear, rather than the forward, portion of the conveyor assembly 36. Associated circuitry, described below and illustrated in FIG. 7C, includes a delaying element 220.
OPERATION
Assume the sorting station 16, 18 and 20 are arranged as above described and illustrated, the drive rollers 50, 74 and 94 being rotated in a counterclockwise direction (FIG. 2) to advance articles 70, picked up by the first conveyor belt assembly 22 from the folding apparatus 12, rearwardly toward the second and third stations 18 and 20.
When an article 70 is advanced by the first conveyor assembly 22, the leading edge 198 thereof contacts the actuating rod 194 of the switch 190, thereby closing such switch (FIGS. 2 and 3). Referring to FIG. 7A, closing of the switch 190 actuates the timer 200, which is preset for the length of time the longest article to be sorted will take, considering its length and its advancing speed, to be advanced from a position contacting the switch actuating rod 194 to a position centered over the discharging blades 110 and 112. Initial closing of the switch 190 by the article 70 actuates the timer 200; subsequent opening of such switch resets the timer. Internal switching portions of the timer 200 do not close until the preset time has elapsed.
As the article 70 continues to be advanced past the switch 190, the leading edge 198 thereof contacts the actuating rod 196 of the switch 192, thereby closing that switch and maintaining it in a closed condition as long as the article is in contact therewith. The article 70 still continues to be advanced.
If an article 70 has a length equal to or greater than the length desired to be discharged by the first discharging assembly 24, the article will still be in contact with the actuating rod 196 of the switch 192, maintaining that switch closed, when the preset time on the timer 200 has elapsed and the internal switching portion of such timer closes. In such a case, voltage is applied through the timer 200 and the switch 192, to the solenoid valve 174 which controls the brake assembly 158, thereby actuating the brake assembly to cause the braking portion 162 to contact the roller 50 and stop rotation thereof. The roller 50 is frictionally mounted upon the drive shaft 54 so that the drive shaft continues to be rotated by the drive chain 68, even after rotation of the roller 50 has ceased. When the roller 50 is stopped, the conveyor belts 62 and 64 are also stopped.
Voltage is simultaneously fed, through the timer 200 and switch 192, to the delaying circuit 202 which, after a delay sufficient to allow complete stopping of the conveyor assembly 22, supplies voltage to the solenoid valve 134 to actuate the cylinder 132 and cause opening of the blades 110 and 112 of the discharging assembly 24 (FIG. 5). Actuation of the cylinder 132, which directly opens the blade 110 also causes, through the linkage comprising links 140 and 146 and bar 142, simultaneous opening of the blade 112. Opening of the blades 110 and 112 allows the article 70, which has just previously been brought to a stop, to drop straight downwardly onto the conveyor belt 180 of the receiving assembly 26. The purpose of stopping the conveyor belts 62 and 64 before discharging the article is to prevent the article's momentum from causing overshooting of the receiving conveyor belt 180. A neat stack can therefore be made on the belt 180.
If, however, an article 70 is shorter than the length determined by the timer 200 (that is, shorter than an article to be discharged at the first sorting station 16), the article will be advanced completely past the switch 192, thereby releasing its actuating rod 196 and opening the switch before the time preset on the timer 200 has elapsed. Since the switch 192 will be opened before the internal timing switch of the timer 200 is closed, neither of the control valves 170 or 134 will be actuated and the article will therebore be advanced by the conveyor assembly 22 across the plate 42 to the second sorting station 18.
Operation of the circuitry depicted in FIG. 7B for the second sorting station 18, is substantially identical to that described above. Closing of the switch 204 by an article 70 advancing from the first sorting station 16 starts the timer 212 which is preset at a time less than that of the timer 200 so as to cause discharging of articles from the second sorting station 18 which are shorter than those discharged from the first sorting station 16. If the article is of a length to be discharged at the second sorting station, its rate of advancing will maintain the switch 206 closed until the internal switch of the timer 212 is closed. In such a case, voltage will be applied, through the switch 206 and timer 212, to a solenoid valve 172a of the brake assembly 176 associated with the roller 74, and the roller will be stopped. After a short delay, caused by the delaying element 214, a solenoid valve 134a will be actuated to cause actuation of a pneumatic cylinder 132a associated with operation of the discharging blades 82 and 84. The article 70 will thereby be dropped onto the conveyor 182 of the second receiving assembly 34.
Again, if an article 70 is so short that it is advanced out of contact with the switch 206 before the time preset on the timer 212 has elapsed, the article will not be discharged from the second sorting station 18, and will be advanced onwardly by the conveyor belts 82 and 84, across the plate 44, to the third sorting station 20.
The third sorting station (unless manually over-ridden) discharges all articles 70 not discharged by the first and second sorting stations 16 and 18. When an article 70 contacts and closes the switch 216, voltage is applied through the switch to a control solenoid valve 174b (FIG. 7C) thereby actuating a pneumatic cylinder 170b associated with the brake assembly 178 adjacent the roller 94 and stopping the roller. After a delay caused by the delaying element 220, a solenoid valve 134b is actuated, causing actuation of a pneumatic cylinder 132b associated with the discharging blades 152 and 154 and thereby opening the blades and discharging the article 70 onto the conveyor belt 184 of the third receiving assembly 40.
As illustrated and described above, the article sorting apparatus 10 will sort articles into three different article length categories: longest articles being discharged at the first sorting station 16, articles of intermediate length being discharged by the second sorting station 18 and all other articles being discharged by the third sorting station 20. It will now be apparent that by the addition of more sorting stations similar to the first or second stations 16 or 18, sorting of articles into as many size categories as may be desired can readily be accomplished.
Other variations will occur to those skilled in the art and are within the scope of the invention. Electrical bypass means may be provided for selectively causing articles to pass through the first and second sorting stations 16 and 18, without being sorted, so that they will be discharged at the third sorting station 20. Such bypassing may be accomplished, for example, as illustrated in FIG. 8, by an operator depressing a momentary-on switch 222 which temporarily opens, by means of a conventional presettable timing relay 224, the line in which the switches 180 and 204 or 192 and 206 are located for a time predetermined to be sufficient to cause the preselected article to be advanced to the third sorting station 20. The switch 222 may be positioned for operation by an operator feeding articles into the folding apparatus 12, the timing relay 224 being set for a time sufficient to allow the preselected article to be advanced through both the folding apparatus and the first and second sorting stations 16 and 18. In the event that such a bypass mode of operation is desired, the third sorting station 20 should be sufficiently long to accommodate the longest articles ordinarily sorted. That is, the first and third sorting stations 16 and 20 should be about the same length. Otherwise, where such bypassing is not employed, all stations may be constructed of decreasing lengths. However, even with a manual bypass provided, the second station 18 may be constructed shorter than the first and third stations 16 and 20.
If desired, another set of normally-closed contacts of the bypass switch 222 can be caused to temporarily open the line containing the switch 216 associated with the third sorting station 20, so that the articles are discharged out an open end portion 226 (FIG. 1) of the sorter, rather than through the discharging assembly 38. If such a variation is employed, the third sorting station 20 need not be constructed to be longer than required for normal sorting of articles thereby, and the three stations 16, 18 and 20 may be of decreasing length.
Another variation, particularly adapted to the apparatus of my prior U.S. Pat. No. 3,462,138, incorporates a "jam circuit" to cause an alarm to be given and the folding machine to shut down if an article fed into the machine is not discharged from the machine within a predetermined time -- an indication of the article being caught or jammed somewhere within the machine. The switches 190 and 204 or 192 and 206 can be easily connected, in an obvious manner, to momentarily deactivate the jam circuit, such a circuit being otherwise wired to sound an alarm and stop the machinery if an article fed into the folding apparatus 12 is not discharged by the third sorting station 20 within a preselected length of time.
It is also possible to incorporate counting circuitry and counters responsive to operation of the various sorting stations 16, 18 and 20, whereby the count of articles discharged by each of the stations can be automatically obtained, a separate counter being provided for each station. In addition, a total article counter may be provided.
Although the automatic sorting apparatus 10 has been described and illustrated as normally (without manual bypass) discharging longest articles from the first sorting station 16 and shortest articles from the third sorting station 20, the arrangement may be reversed, with minor circuitry modifications, to cause the shortest articles to be discharged at a first sorting station (corresponding to station 16) and the longest articles to be discharged from a third sorting station (corresponding to station 20). Such an arrangement may be accomplished by providing that switches corresponding to the switches 192 and 206 be normally closed, rather than normally open, so that an advancing article causes the switches to be open. In that manner, for example, a short article will pass the switch corresponding to switch 192, allowing it to be closed when the preset time of the timer 200 has elapsed, thereby causing stopping of the first conveyor assembly 22 and opening of the first discharging assembly 24; a longer article will maintain the switch open when the timer switch closes, thereby causing the article to be advanced to the next sorting station.
Other variations are also within the scope of the invention. For example, optical switches may be used in place of the microswitches 190, 192, 204, and/or 216. Also other article parameters may be sorted upon. For example, a light source and an optical detector may be employed to allow sorting according to the optical reflectivity of the articles, articles of a first predetermined reflectivity being caused to be discharged, generally in the above-described manner, at a first sorting station, articles of a different reflectivity being caused to advance to a next sorting station, etc. In such manner, colored articles or articles of the same color but of different materials, may be easily sorted.
Thus, although there have been described herein specific arrangements of an automatic article-sorting apparatus in accordance with the invention for the purpose of illustrating the manner in which the invention may be used to advantage, it will be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of the invention as defined in the appended claims.
What is claimed is: | An automatic laundry sorting machine comprising separate sorting stations having individually driven conveyor units for feeding and sorting folded laundry articles according to size. Sorting and sensing means are associated with at least one of the conveyor units to actuate a release mechanism for articles of selected predetermined size. Articles of other sizes are not released but are passed to subsequent stations where further sorting may occur. Articles not fitting any of the predetermined size-sensing criteria can be passed or by-passed through the conveyor units and discharged outside the system. Alternative embodiments including counters strategically placed in subsequent stations and unique jam eliminating circuitry are described. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a NON-PROVISIONAL DIVISIONAL UTILITY PATENT APPLICATION, based on the Mother patent application Ser. No. 11/325,653 Filed 1/3/2006 Title “LIGHT SOCKET 3”, Ref 4 , [still pending at the USPTO, as of the filing date of the present application], which in turn is a Divisional Patent Application based on Mother patent application Ser. No. 10/953,600 Filed Sep. 28, 2004 Title “INTERPOSER”, Ref 3 , [Now U.S. Pat. No. 7,121,891 Issued Oct. 17, 2006], which again in turn is a Divisional Patent Application based on Mother patent application Ser. No. 10/391,417 Filed Mar. 17, 2003 Title “LIGHT SOCKET”, Ref 2 , [Now U.S. Pat. No. 6,979,230 Issued Dec. 27, 2005].
[0002] This application is claiming the priority and benefits of ALL the mother patent applications mentioned above, which are incorporated herein in their entirety by reference and which will be referred to as listed below.
[0003] This application is claiming also the priority and benefits of the same reference, which was claimed by the mother applications. That reference is Provisional Patent Application Ser. No. 60/366,294, filed on Mar. 20, 2002, entitled “Lamp Sockets & Micro-Probes”, which is also incorporated herein in its entirety by reference, and which will be referred to as Ref 1 .
[0004] Note:
[0005] I will refer in this application to certain pages, drawings or sketches that are included in the above Reference. I would like to explain here the numbering system that was used in that reference, so that it will be clear, which page or drawing I would be referring to later on. I will use Ref 1 to illustrate.
[0006] Ref 1 covers 2 product groups. They are 1) Lamp Sockets or simply Sockets and 2) Micro-Probes or simply Probes.
[0007] The pages in Ref 1 are identified as follows. The pages of the Lamp Sockets are identified by LS, and those of the Micro-Probes are identified by MP.
[0008] Each one of these two groups' documents was divided into three sections. The Specifications, the Drawings and the Additional Documents. The pages were identified as follows as well. The pages in the Specifications sections by S, the Drawings by D, and the Additional Documents either by AD or by A.
[0009] So for example, page 7 in the Specifications of the Micro- Probes group would be marked thus: “MP-S-7”.
[0010] PS: During the prosecution of the mother application, I was requested to clean-up the drawings, which I did. So, the drawings included in this Divisional Application reflect those improved drawings.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0011] Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
[0012] Not Applicable
DEFINITIONS
[0013] For the purpose of the following invention description, I will use certain words or terms that may be peculiar to this application. They will be explained in the following definitions, or as I go along during the application.
[0014] Beside the Ref #s, I will sometimes use the following legend to identify certain parts, although this may be superfluous.
[0015] B for Bulb, S for Socket.
[0016] BR for Bulb Return, SR for Socket Return.
[0017] SC for Socket Central Contact, SM for Socket Middle Contact.
[0018] H for the Socket Hot Terminal.
[0019] A, B, C, D for the four Faces of the Rotating Cam in the Socket.
[0020] F for the Free shape of any spring, A for the Acting position of any spring and S for Seated or fully compressed position of any spring.
[0021] “F” means the FREE shape of any spring.
[0022] “A” means the ACTING shape or position of any spring.
[0023] “S” means the SEATED shape or position of any spring.
[0024] BMCR, Ref # 3 =Bulb Middle Contact Ring.
[0025] SMCE, Ref # 31 =Socket Middle Contact Element.
[0026] Stop, Ref # 31 =The same rigid SMCE, Ref # 31 .
[0027] SCCS, Ref # 23 =Socket Center Contact Spring.
[0028] Solder Spot, Ref # 19 =The connecting spot, or connecting means, which usually is a solder spot, or solder joint, located on the BMSR, to one or more filaments or other elements, inside the bulb. I will use the following terms in the Specifications and in the claims as synonymous: solder joint, solder spot, connecting spot, connecting means.
[0029] Definitions
[0030] Rigid vs. Flexible or springy
[0000] See Specifications, under 3. HOW THE 3-WAY SOCKETS WORK.
BACKGROUND OF THE INVENTION
[0031] 1. Field of the Invention
[0032] The present invention generally relates to electrical contacts and elements and their surfaces and physical properties, and especially to electrical light bulbs and to electrical sockets. More particularly it relates to 3-way electrical light bulbs and their electrical sockets and related components. The invention also relates to 3-way light sockets, whether they incorporate a switch or not. The invention further relates to washers or devices or inserts or adapters in general that can be used in conjunction with such light bulbs and/or their sockets.
[0033] 2. Reference to a Related Article
[0034] The January 2002 issue of “DESIGNFAX” Magazine had, in page 64, an interesting article that triggered my thoughts towards the inventions covered by this application.
[0035] The article in question was entitled: “Side Jobs”, or “Problem of the Month”. I have copied it and am attaching it as “Additional Documents” at the end of this application. A photocopy of the articles is shown in page LS-A-2. It is not quite legible. So, I scanned the article and with OCR, I created a “text” version of it and I am showing it in page LS-A-1.
[0036] The gist of the article is the problems that are found with 3-way light bulbs and their sockets. These sockets are referred to sometimes as light sockets and other times as lamp sockets. Most of the sales packages of such sockets, on the market, refer to them as lamp sockets. So, in this specification I will most often use the term “lamp socket” or simply “socket”.
[0037] The referenced article states the following complaint.
[0038] “Recently, one of our staffers posed this problem to us. Why is it, he asked, that they can't make a decent three-way light bulb? It seems that all four 3-way lamps in his house are afflicted with flicker—that is, when switched to the lowest or highest output, the light tends to blink on and off.
[0039] Adjust the contacts? Yes, he's cleaned and adjusted the contacts of the sockets of all the lamps (unplugged from the wall first, of course), as well as sanding and cleaning of the bulbs. In frustration he's just installed single-wattage bulbs into the fixtures—obviously a solution, but it does offer a challenge. So we ask you for suggestions, not just for our staffer's immediate illumination needs, but also for alternative designs that won't require the complete overhaul of existing light-bulbs and can be done for a low cost.”
[0000] Person Verification
[0040] I, the inventor, remembered that occasionally I, too, had the same “flicker” problem with some of my 3-way light lamps in my house.
[0041] However, I wanted to verify that the problem really existed. So I talked to a friend of mine, whose name is Ed V.E. Ed is an electrician and teaches the trade to aspiring electricians at a local college. At one time, Ed was working with a large local company and was responsible for the maintenance operation, especially the electrical side of the operation. That company owned a few hotels, among other things. Ed told me the following.
[0042] Yes, there is a problem with 3-way electrical light bulbs and their sockets. It was so bad, that at one time, some companies have tried to solve the problem, but have given up. He remember that Phillips and Duro-Test had offered some solutions, but they were either too expensive or did not get enough appeal or acceptance from the market.
[0043] One solution was very expensive compared to regular 3-way light bulbs. The “improved” bulbs was “guaranteed for long life”, but their cost was prohibitive.
[0044] Another solution was to provide the light bulb with a wavy spring instead of the solid ring. But for some reason, this solution did not work either. Not successful. Did not last long on the market.
[0045] Ed recalled also that they were telling the maids, at the company's hotels, not to tighten the light bulbs into the sockets too tightly. But that did not help either. It seems that the maids noticed the flicker. So, they thought that the bulb was not seated properly. So, they went and tried to tighten the bulb more in the socket, and they often broke the bulbs.
[0046] Then, I did a small market search.
[0047] This is what I discovered.
[0000] Potential Problem Sources
[0048] I discovered basically THREE potential sources for the problem:
1. The bulbs have a problem, but by themselves and on their own, they are OK. 2. The sockets have a problem, but by themselves and on their own, they are OK. 3. The system, or the combination of, using such bulbs and sockets creates problems. It is mainly the orientation or correlation of the threads in the bulbs and sockets together with the presence of the solder spot 19 of the bulb that create the problems.
Potential Problem Source #1: The bulbs have, or could Cause a Problem.
[0052] The problem is the way the middle contact ring 3 of the bulbs is manufactured. Here is what I mean. The bulbs, as shown in FIGS. 1 & 2 , are made with the standard center contact point 1 , like the standard one-way bulbs, also known as “one-wattage bulbs, plus a middle contact ring 3 , that is located between the center contact point and the outside bulb threaded metal base 5 , that acts as the return terminal. Insulations 7 and 9 are in-between for proper electrical separation.
[0053] The bulb middle contact ring 3 is connected to the middle filament 11 inside the glass body 13 of the bulb 15 by soldering the filament wire 11 or the filament carrying wire 17 to the bulb middle contact ring 3 . The solder joint 19 is usually pretty rough, bumpy and out of plane with respect to the bulb middle contact ring 3 itself, i.e. it is higher than the rest of the surface of that bulb middle contact ring 3 . It protrudes over the surface of the bulb middle contact ring 3 and it creates an uneven contact surface. Sometimes, it protrudes as high as 0.030 inch or higher, over the surface of the bulb middle contact ring 3 .
[0054] So, when a person inserts such a bulb into the socket 21 in FIG. 3 and turns it in, and “reaches bottom”, the contact elements inside the socket would touch the corresponding contact points of the bulb. First, you make contact between the center points and then you make contact between the middle contacts. I will explain what occurs at this time, in a moment.
[0000] Potential Problem Source #2: The Sockets have, or could Cause a Problem.
[0055] The 3-way sockets have three contact elements that touch three corresponding elements of the bulb.
[0056] FIG. 3 shows a cross-section view of such a 3-way bulb sitting inside a 3-way socket. FIG. 4 shows a close-up view of the socket. FIG. 5 and the subsequent figures show an even larger close-up view.
[0057] When a light bulb is properly seated in the socket, the following three pairs of elements are making contact.
[0058] 1. The bulb threaded metal base 5 is touching the socket threaded shell 27 .
[0059] 2. The center contact point 1 of the bulb is touching the center contact spring 23 of the socket. Actually, the socket center contact spring 23 is applying a certain contact force against the bulb center contact point 1 , pushing the bulb threaded metal base 5 upwards against the thread of the socket threaded shell 27 , by an equal amount of force.
[0060] 3. The bulb middle contact ring 3 is touching the socket middle contact element 31 .
[0000] How Present Bulbs and Sockets Work
[0061] I will describe how they work, in three different steps, as follows. I will use FIGS. 1 through 8 . While doing this, I will also point out the potential sources of problems, and possibly mention briefly some suggestions for corrective action. I will then elaborate later on these suggestions.
[0062] A—HOW 1-WAY (SINGLE-WATTAGE) BULBS WORK IN THEIR SOCKETS
[0063] B—HOW 3-WAY BULBS WORK IN THEIR SOCKETS
[0064] C—HOW THE 3-WAY SOCKETS THEMSELVES WORK.
1. HOW 1-WAY (SINGLE-WATTAGE) BULBS WORK IN THEIR SOCKETS
[0065] Now, I will first describe the standard one-way bulb and its corresponding socket, and how they interact. Then I will compare them with the 3-way bulb and socket.
[0066] The sockets for standard one-way bulbs have only one contact spring, the socket center contact spring 23 , in the center of the socket, which is similar to the center contact spring 23 of the 3-way socket, to make contact with the center point 1 of the bulb, which again is similar to the 3-way bulbs from this respect. They do not have the “stop” 31 , which we see in the 3-way sockets. The return current goes through the bulb threaded metal base 5 to the socket threaded shell 27 of the socket. This is similar to the 3-way sockets. The center contact element 23 of the socket 21 is a “spring”, as I said. When a person threads a bulb into the socket, one of two things can happen. First, if the power is already turned on, then when the bulb is threaded in far enough for the bulb center contact point 1 to reach the socket center contact spring, the light would turn on, and most probably the person would stop and leave the bulb at that position. It is not the ideal thing to do. If the bulb is wiggled slightly, there could be a good chance of getting some flicker, because the socket center contact spring may separate from the bulb center point 1 . The second thing that can happen is that the person would thread the bulb in a little bit more. This would be advisable. But when would you stop? Most of the time, you would stop when you feel enough resistance to the threading process. You could keep on threading the bulb in, all the way, until the bulb has bottomed down all the way into the socket. This is probably the best way. At this situation, the socket center contact spring 23 would be compressed all the way down and would be seated on top of the bottom part 29 of the socket. This should not harm the contact spring because the spring should still have enough springiness (flexibility) in it to work with this bulb or any other replacement bulb that may be inserted later in the same socket.
[0067] So far so good, for standard one-way bulbs. But now let us compare this with the 3-way bulbs and their sockets.
2. HOW 3-WAY BULBS WORK IN THEIR SOCKETS
[0068] The 3-way sockets 21 have two contact elements beside the return, instead of only one in the 1-way sockets. The first contact element is the center contact spring 23 . This is exactly like the one for the standard one-way sockets as mentioned above. The second contact element is what I call the socket middle contact element 31 . And this is the one part that creates the major part of the problem, as far as I can see.
[0069] The socket middle contact element 31 of all the 3-way sockets that I have found in the market is “RIGID”. It is not springy like the center contact spring. It seems the manufacturers of these sockets wanted to use this MC as a “STOP”. This is my interpretation of the existing design and the thought process behind it.
[0070] The way I see it, this is what happens.
[0071] When you thread the 3-way bulb into the socket, you first make contact with the center points, i.e. bulb center contact point 1 with socket center contact spring 23 , as I said before. You may or may not get the light on, if you have the power on. Officially you should not have the power on, when you are inserting the bulb in the socket. It is dangerous. It can create a spark, which could cause harm. So, you would not know whether you made any contact or not yet. So, you keep threading the bulb in further until you feel some appreciable resistance. This is most probably when the middle contact ring 3 of the bulb touches the socket middle contact element 31 of the socket. This is the time when your luck can be very important. If you hit the socket middle contact element 31 with a point on the bulb middle contact ring 3 that does not have the solder joint 19 on it, or near it, you should be OK. But, if the solder joint 19 just happens to be near the area where you are touching the socket middle contact element 31 , then you may hit a high spot at one instant and then you may hit a low spot at another instant. The change can be just a slight change in turning the bulb or some other change due to temperature or whatever. Basically you create an “unstable” electrical contact, and that is the bad news. Another possibility is that if you have threaded the bulb in just enough to make electrical contact, but “mechanically” the contact (touching) is not strong enough, the electrical resistance at the contact area can be relatively high. This could create some localized heating, which in turn could create some expansion and contraction at the local contact area and that can create havoc with the system.
[0072] This is my interpretation of the problem. Also based on my experience with connector and interconnection device, I would not design a connector or a socket with such a rigid contact element. It is simply not done, as far as I know.
3. HOW THE 3-WAY SOCKETS THEMSELVES WORK
[0073] FIG. 1 shows the basics of the 3-way light bulb, with the filaments and the filament carrying wires “simplified” for clarity of illustration.
[0074] FIG. 2 shows a close-up view of the lower portion of the same bulb.
[0075] FIG. 3 shows a cross-section of the socket, with a bulb in it.
[0076] FIG. 4 shows an enlarged view of the lower portion of FIG. 3 .
[0077] FIGS. 5 through 8 show an even closer view of the main mechanism of the socket and the base of the bulb with the different contact elements of both. They also show the four different positions of the switch that controls which filament will be turned on or off, at any of these four positions. I will explain.
[0078] FIG. 5 shows the position of the switch cam 41 , which I will refer to also as the rotating cam 41 , when no filaments are on. The light is OFF.
[0079] FIG. 6 shows the position when the “middle filament” 11 is ON. The power is connected from the switch hot wiper 43 through the rotating cam 41 , to the switch middle wiper 45 , and then from it to the “RIGID” socket middle contact element 31 , which touches bulb middle contact ring 3 . Then the power flows from there to the middle filament 11 and then back to the bulb threaded base 5 and from it to socket threaded shell 27 . So, the result is that the middle filament 11 will be turned ON.
[0080] Please note that the rotating cam 41 has four cam surfaces, cam surface B 49 , cam surface C 51 , cam surface D 53 , and cam surface A 55 . The rotating cam 41 itself is made of an insulating material. So, if any contact element is touching cam surface A 55 , then no electrical power can be conveyed to it.
[0081] However, each of the other three cam surfaces, i.e. cam surface B 49 , cam surface C 51 , cam surface D 53 are covered by a metallic surface, which is connected to a metallic plate 57 , shown in dotted lines, in the back of the rotating cam 41 . So, these three cam surfaces are connected electrically to each other.
[0082] Consequently, in this position in FIG. 6 , the switch hot wiper 43 is connected to cam surface B 49 , which in turn is connected to cam surface D 53 through the hidden metallic plate 57 , which then is connected to switch middle wiper 45 .
[0083] FIG. 7 shows the position when the “center filament” 10 is ON. The power is connected from the switch hot wiper 43 through the rotating cam 41 , through cam surface C 51 , the hidden metallic plate 57 , cam surface B 49 , to the switch center wiper 59 , which is integral with the “springy” socket center contact spring 23 , which touches the bulb's Center Contact Point 1 . Then the power flows from there to the center filament 10 and then back to the bulb threaded metal base 5 and from it to the socket threaded shell 27 . So, the result is that the center filament 10 will be turned ON.
[0084] FIG. 8 shows the position when both the “center filament” 10 as well as the “middle filament” 11 are ON. The power is connected from the switch hot wiper 43 through the rotating cam 41 through cam surface D 53 and hidden metallic plate 57 , to the switch center wiper 59 as well as to the switch middle wiper 45 through cam surface D 53 , hidden metallic plate 57 , cam surface B 49 , and then from there to the two bulb filaments 10 and 11 , as described above. So, the power flows through both filaments 10 and 11 , which then will be turned ON.
[0085] In all these four figures, we can see that the socket center contact spring 23 , which is a springy contact, can operate through a large arc. At its highest position 61 , marked “F”, the contact spring is under no load. This position is called the FREE position of the spring, hence the letter “F”. If the spring is compressed all the way down, it will be seated against the bottom 29 of the socket, hence the letter “S” for this position 63 . Usually the bulb is threaded down until it is seated on the socket middle contact element 31 , which seems to also act as the “STOP”. In this position, the socket center contact spring 23 is at its “acting” position 65 , hence the letter “A”.
[0086] NOTE: Hence, we will use the following legend:
[0087] “F” means the FREE shape of any spring.
[0088] “A” means the ACTING shape or position of any spring.
[0089] “S” means the SEATED shape or position of any spring.
[0000] Discussion RE the Socket Middle Contact Element 31
[0000] The Purpose of this Part and the Effect of the Fact that it is Rigid.
[0090] The socket center contact spring 23 has a wide range of acceptable positions, practically from position F 61 through position S 63 , FIGS. 1 through 8 . Ideally, the operating position 65 of the spring should be somewhere close to the center of its range. The way it is shown here in all the figures is pretty good.
[0091] This socket central contact spring can be considered as an ideal electrical contact spring. The reasons are: 1) It has a wide range of elastic travel. When it is fully seated, i.e. pushed as far down as it can go, it does not undergo any permanent plastic deformation, i.e. once released, it goes back to its original free position, hence it does not loose its force-deflection curve characteristics. 2) When the bulb is threaded in, the spring applies a force that is relatively constant. It is a relatively soft spring, and its force-deflection curve is relatively flat. This means the force magnitude remains roughly the same, for slight changes in the position of the bulb.
[0092] Compare this with the socket middle contact element 31 below.
[0093] The socket middle contact element 31 is a rigid mechanical part. You may have noticed that I keep referring to it as an “element”, not as a “spring”. In reality, every mechanical part can be considered as a spring. When a force is applied to any mechanical part, it will flex to some extent. But under the same amount of force, we can intuitively see that a member like the socket middle contact element 31 would deflect an infinitesimal amount, compared with the deflection of a member like socket center contact spring 23 under the same amount of force. So, for all practical purposes, we can safely say that socket middle contact element 31 is not a spring, but is a rigid body.
[0094] The way I see it, the original purpose of the socket middle contact element 31 seems to be two-folds. First and foremost, it is supposed to function as an electrical contact. And incidentally, it is also supposed to function as a mechanical stop, I guess. I personally do not see the need to have a mechanical stop, because the bulb can safely be threaded in all the way until the central spring is fully seated against the floor 29 of the socket. This is what happens with the single wattage light bulbs. They do not have and do need an additional element to act as a stop. So, why would a 3-way bulb need one? So, if the sole purpose of socket middle contact element 31 is to act as an electrical contact spring, then a better design is needed. And this is what I am offering here by this invention.
[0095] What happens when we thread a light bulb in such a socket against this socket middle contact element 31 . If the bulb is pushed tightly against it, by threading/turning it tightly, then the top surface of socket middle contact element 31 starts to rub and scratch the surface of the bulb middle contact ring 3 . The socket middle contact element 31 would not deflect like the socket center contact spring 23 . It would stand its ground. What would give in is the softer surface of the bulb middle contact ring 3 . The socket middle contact element 31 may dig in and create a slight grove in bulb middle contact ring 3 . This can continue until the resistance against further turning the bulb becomes too great, so we stop turning. This is fine. What we get in this case is two things. First, the scratching and digging exposes clean base metal on both surfaces of socket center contact spring 23 and socket middle contact element 31 and creates a good electrical connection. At the same time, it creates a stable mechanical connection, where the two parts are “locked-in” and would not be unlocked unless forcefully done so. Such a locked-in mechanical situation makes for a mechanically stable connection, and a relatively permanent one. Thus, the electrical contact in this case would be good and acceptable and it would work for a long time.
[0096] However, once in a while, we get the elevated rough uneven solder spot 19 in the picture. If the orientation of the thread on the base of the bulb, and the orientation of the socket threaded shell 27 , and the circumferential position of the solder spot 19 , all work in some strange way, we would end up having the solder spot 19 hit socket middle contact element 31 while we are just about ready to make the electrical/mechanical contact with it (socket middle contact element 31 ). It is like when the stars line up once in a while. If that happens, then we have a problem. This is what happens.
[0097] The solder spot 19 would hit the socket middle contact element 31 against its side, not along its upper surface. This is because the solder spot 19 is higher than it adjacent ring surface. This would prevent the bulb from turning any further. The user would feel the resistance against turning, so he would stop turning any further, thinking that he has done a good job inserting/installing the bulb into the socket. In fact, there is a “temporary” mechanical as well as an electrical contact at that moment, but in reality it is an unstable contact because the mechanical contact is unstable. It is not “locked-in”, as compared to the previous situation described above. There is not enough friction or other restrains that would ensure that the solder spot 19 would remain in that position forever. Any slight disturbance may “dislodge” the spot from this position and would push it away from socket middle contact element 31 . If that happens, then we would get an open electrical circuit and the electrical current/power would be interrupted and the light would go off. The disturbance could move the spot away from socket middle contact element 31 just temporarily or permanently. If it were temporary, then it would be a worse case. Because the electrical power would be interrupted for a short moment and the light would go off, and then the disturbance would push the spot back against the socket middle contact element 31 and the power and light would go on again. This may repeat often enough and we would get the undesirable “flicker”. This disturbance could be a vibration from any outside source or could be due to temperature fluctuation or any other source. The disturbance does not need to be extremely large. Even a few thousandth of an inch movement could result in such an undesirable result. Again, the reason is that the contact between the spot and socket middle contact element 31 is not a “stable” one, as explained above. The connection is not locked-in mechanically, so it is unstable and unreliable.
[0098] In contrast, if we do the same thing with a contact spring, like socket center contact spring 23 , and we move the bulb by similar distances, the electrical current flow would hardly be affected at all. The contact spring, being elastic, would “follow” the bulb and would still exert/apply approximately the same amount of contact force, thus maintaining the required conditions for a good electrical connection. We would not get any interruptions in the current flow and the light would stay on and would not flicker.
[0000] Back to the Problem
[0099] So, the problem, as explained above, is with the rigidity of socket middle contact element 31 of the socket in conjunction with the elevated uneven surface of the solder spots 19 of the bulbs and their position on the bulb middle contact ring 3 .
[0100] Please note that if the socket is used by itself, then there is no problem. It works OK. Similarly, if the bulbs are used by themselves, then again there is no problem. They would work. However, when you use them together, then the problems arise.
[0101] If we look at FIGS. 5 through 8 , we notice the solder joint 19 represented by the irregular blob at the left side of the bulb middle contact ring 3 . It is shown at that position simply for illustration purposes. In reality, we do not know where it ends up, when the bulb is threaded into the socket. It can be exactly at the position shown, or it can end up right on top of socket middle contact element 31 , or anywhere in between. If it happens to end up close to SM, then we can expect some difficulties, as explained above. In other words, if this happens, then we could get an intermittent contact, i.e. the electrical power may not be steady. It may be readily interrupted, thus creating the “flicker”, or the contact resistance could be high, creating a hot spot, etc.
[0102] To repeat then, one source of potential problem is the fact that socket middle contact element 31 is rigid. This can be a problem, regardless of where the solder joint 19 ends up. During the operation of the bulb and socket system, the elements of the system gets exposed to varying temperatures. The result is that the elements change temperature and consequently expand or contract accordingly. Any such changes can force the contact elements to get closer to each other, which is not too bad. On the other hand, the contact elements could get farther apart. This is where trouble starts. We would get what could be considered an open circuit. Or at least, it could be a high resistance contact condition. In either case, the power could become discontinued or lowered because of the open circuit or the high resistance. This can manifest itself as the dreaded “flicker”.
[0000] A Personal Experiment
[0103] To determine the Location of the Bulb Solder Spots 19 with respect to socket middle contact element 31 .
[0104] I have purchased five 3-way light bulbs at random from a local store. I have inserted each one of them into one and the same 3-way socket, and threaded them down until I hit “bottom”, i.e. until I felt enough resistance against threading in the bulb any further.
[0105] I have marked the rotational location 73 of each bulb with respect to a specific point on the socket. See the black mark 71 on the thread of the bulb, as shown in Picture 1 .
[0106] In Pictures 2 and 3 , the five bulbs, 71 , 75 , 79 , 83 and 87 , are positioned with their black marks, 73 , 77 , 81 , 85 and 89 , roughly in the same angular position, namely facing the viewer. It can be seen that the solder spots 19 of each of the five bulbs, on bulb middle contact ring 3 , are not in the same comparable angular positions. They are distributed randomly around the ring, as follows:
[0107] Bulb # 1 71 has the solder spot 19 spread from around 2 o'clock to around 5+o'clock.
[0108] Bulb # 2 75 from around 3 o'clock to around 5+o'clock.
[0109] Bulb # 3 79 from around 12 o'clock to around 2+o'clock.
[0110] Bulb # 4 83 from around 9 o'clock to around 10+o'clock.
[0111] Bulb # 5 87 from around 8 o'clock to around 9 o'clock.
[0112] Obviously, the bulbs are not consistent, as far as the angular location of the solder spot 19 with respect to the thread on the bulb base 5 is concerned.
[0113] Out of these five bulbs, one bulb ended up with the solder spot 19 hitting the rigid middle contact/stop element 31 of the socket. You may notice that I will refer to the socket middle contact element 31 also as the “stop 31 ” or the socket middle stop 31 . This created an interference. It prevented the bulb from being rotated any further. The bulb simply hit the stop 31 and stopped rotating. It is because the high shape of the solder spot 19 hit the side of the stop 31 , instead of its top contact surface, as it should do. This prevented the bulb from rotating any further. This type of “touching” could be considered a false contact condition and makes for an unstable contact and could create “flicker”.
[0114] Although this has not been a statistically rigorous experiment, still one out of five bulbs proving defective is a high percentage (20%) of defects among this small sampling.
PRIOR ART
[0115] As far as I know, there has never been any prior art covering anything similar to the concepts offered in this present invention. I am not aware of any. I am sorry; I could not find any.
[0116] In the following specifications I will propose some solutions that could help.
SUMMARY OF THE INVENTION
[0000] Summary of the Invention
[0117] The present invention addresses the contact elements of the 3-way light bulbs and their corresponding sockets.
[0118] The invention tries to solve the problem at either side. First, it proposes some solutions that can be introduced and implemented for/with the sockets. Second, it proposes some other solutions that can be implemented for/with the bulbs themselves.
[0119] Then it addresses the system that comprise both a Bulb and a Socket together and the interaction between them.
[0120] And then it introduces some add-on devices that can be used as inserts or adapters, in conjunction with the bulbs and sockets.
[0121] The basic goal is to provide contact elements that can absorb and/or compensate for the expected irregularities in the surface of the bulb middle contact ring 3 , or eliminate the irregularities or provide means to be able to live with such irregularities.
[0122] First, the sockets could have springy middle contacts. A number of alternatives are being proposed.
[0123] Second, the bulb could be manufactured such that the connection spot is flush with the surrounding general surface of the bulb middle contact ring 3 . Other alternatives related to the bulbs will be considered. For example, we could provide some springy cushiony elements at the bulb middle contact ring 3 . These could include a simple conductive paste or grease (although this may be hard to control) or some conductive sponge-like material, in the form of a washer or ring or doughnut, or inserts or adapters in general. Of course, we must at the same time ensure that this conductive material does not touch other contact elements. Note: Sometimes, I will use the spelling “donut” for “doughnut” and vice versa. It seems they are acceptable as interchangeable spellings.
[0124] Thirdly, the bulbs and the sockets could be manufactured in a way such that the orientation of the thread of either the socket shell of said socket and/or the bulb base is such that when a bulb is inserted into a socket and is threaded in all the way until fully seated, then the connection spot of the bulb will not touch, actually will not be near enough to touch the socket middle contact element 31 .
[0125] Fourthly, the add-on devices that can be used as inserts or adapters, in conjunction with the bulbs and sockets, could be manufactured and sold separately on the after-market, to help the end users in coping with the problems with existing parts, i.e. with those bulbs or sockets that are already on the market and did not take advantage of the present inventions yet.
[0126] Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description wherein I have shown and described only the preferred embodiments of the invention, simply by way of illustration of the best modes contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiment are to be regarded as illustrative in nature, and not as restrictive.
[0000] There will be a few other details offered. They will all be described down below.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
Brief Description of the Drawings
[0127] All the drawings in these specifications, FIGS. 1 through 53 are exact copies of those figures with corresponding numbers, which were included with Ref 1 . However, FIGS. 47 through 51 have a small problem that I will discuss when I fully describe them in the Specifications. I have also added a few more drawings and included some photographic pictures and computer scanned pictures and some 3D-views from a 3D-CAD program, over and above what was included in Ref 1 . I am not sure whether the pictures are permissible to be included in the patent application, but I have included them for information at least. If the Patent Examiner decides against them, then we can discard them and if necessary I can replace them by some other figures that would be more acceptable to the Examiner.
[0128] Drawings 1 through 4 show a 3-way light bulb and a 3-way electrical socket and their components.
[0129] Drawings 5 through 8 show how a 3-way socket works to turn on or off the filaments of a 3-way light bulb.
[0130] Drawings 9 through 22 show two views for each of seven new proposed contact springs as per present invention.
[0131] Drawings 23 through 27 show various 3-D views of one of the new proposed contact springs as per present invention.
[0132] Drawings 28 through 40 show various 3-D views of another one of the new proposed contact springs as per present invention and how it interacts with one of the existing contact elements in an existing 3-way electrical socket.
[0133] Drawings 41 and 42 show two views of an eighth new proposed contact spring as per present invention.
[0134] Drawings 43 through 46 show various 3-D views of the eighth new proposed contact spring as per present invention and how it interacts with one of the existing contact elements in an existing 3-way electrical socket.
[0135] Drawings 47 through 49 show various views of an add-on donut that would interact with the bulb and the socket.
[0136] Drawing 50 shows a view of an add-on ringed donut that would interact with the bulb and the socket.
[0137] Drawing 51 shows a view of an add-on guided donut that would interact with the bulb and the socket.
[0138] Drawings 52 and 53 show two views of the possible locations and/or orientation of the new proposed socket contact springs as per present invention.
[0139] Drawings 54 through 56 show various additional views of the add-on donut, which was shown in drawings 47 through 49 .
[0140] Drawings 57 and 58 show two views of a second add-on, a two-layer donut that would interact with the bulb and the socket.
[0141] Drawings 59 through 61 show various views of a third add-on, a ringed donut that would interact with the bulb and the socket.
[0142] Drawings 63 and 64 show two views of a fourth add-on, a 2-layer ringed donut that would interact with the bulb and the socket.
[0143] Drawings 64 and 65 show two views of a fifth add-on, a guided donut that would interact with the bulb and the socket.
[0144] Drawings 66 through 68 show various views of a sixth add-on, a 2-layer guided donut that would interact with the bulb and the socket.
[0145] Drawings 69 A and 69 B show two views of a seventh add-on, a hard guided donut that would interact with the bulb and the socket.
[0146] Drawings 70 through 74 show various views of new proposed designs for 3-way light bulbs and how they might interact with their 3-way electrical sockets.
[0147] In addition, I am including the following pictures and scans and color 3-D drawings.
[0148] Picture 1 is a photographic picture, which shows a 3-way light bulb, together with certain markings indicating the performance of the bulb in conjunction with a 3-way electric socket.
[0149] Pictures 2 and 3 are photographic pictures, which show 5 such 3-way light bulbs, together with similar marking indicating their performance in conjunction with a 3-way electric socket, showing particularly how each of the 5 bulbs has performed differently than all the others.
[0150] Picture 4 is a photographic picture, which shows two 3-way electric sockets. One of the sockets is a standard conventional 3-way electric socket, while the second socket has been modified as per the present invention.
[0151] Picture 5 is a photographic picture, which shows an enlarged view of the second socket, shown in Picture 4 .
[0152] Picture 6 is a computer scan, which shows two enlarged views of a new contact spring, according to the present invention, and which is being proposed to be used in the 3-way electric socket.
[0153] Picture 7 is a computer scan, which shows the components of a conventional 3-way electrical socket, together with the new proposed spring, that was shown in picture 6 .
[0154] Pictures 8 and 9 are 3-D color drawings, made by a CAD program. They show two 3-D views of the conductive donut that was shown in Drawings 47 , 48 , 49 , 54 , 55 , and 56 .
[0155] Pictures 10 through 12 are 3-D color drawings, made by a CAD program. They show three 3-D views of the ringed donut that was shown in Drawings 50 , 59 , 60 and 61 .
[0156] Pictures 10 through 12 are 3-D color drawings, made by a CAD program. They show three 3-D views of the ringed donut that was shown in Drawings 50 , 59 , 60 and 61 . Picture 12 shows the outside ring as if it were made of a semi-transparent material, so that it would be possible to see some of the internal details of the component inside it.
[0157] Pictures 13 through 15 are 3-D color drawings, made by a CAD program. They show three 3-D views of the 2-layer guided donut that was shown in 66 , 67 and 68 . Picture 15 shows the outside ring as if it were made of a semi-transparent material, so that it would be possible to see some of the internal details of the component inside it. In addition, the inside compressible conductive donut is shown with a special color and texture to indicate the difference between it and the second layer, which is supposed to be of a solid harder metal.
[0158] Pictures 16 through 18 are 3-D color drawings, made by a CAD program. They show three 3-D views of the ringed donut that was shown in Drawing 69 . Picture 18 shows the outside ring as if it were made of a semi-transparent material, so that it would be possible to see some of the internal details of the component inside it.
[0159] FIG. 52 shows an example of the “In-Line” contact arrangement, while FIG. 53 shows an example of the “Offset” contact arrangement. In the Offset arrangement, we can place the new contact spring in line with the socket center contact spring, because the socket middle contact element 31 is out of the way. But, in the In-Line arrangement, we don't have that kind of room. So, in the latter (In-Line) arrangement, we are forced to use the same location for both the new contact spring as well as the socket middle contact element 31 . For this reason, we revert to the arrangement
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0160] While the invention is susceptible of various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.
[0161] While I am describing the drawing in more details, I will at the same time explain the technology basis of the invention. I will also include a number of examples in this section, which should be considered as part of the embodiments for the purpose of this application as well.
[0162] This description covers more than one invention. The inventions are based partly on the same technology platform, but then each of the inventions has some additional features of its own. Not being an expert in handling patents, I would like to leave it to the patent examiner to decide on the number of the inventions contained and how to split one invention from the other.
DESCRIPTION OF THE INVENTION
[0163] As mentioned earlier in the summary, there are several inventions here. I will describe them as we go along. I will however group them into four groups. The specifications will cover these four groups of inventions. Group One will cover inventions related to the Sockets; Group Two, inventions related to the Bulbs; Group Three, inventions related to the Systems that comprise both a Bulb and a Socket together; and finally Group Four, those related to Add-On devices, which I would call as Inserts or Adapters.
[0000] GROUP ONE: Inventions Related to Sockets & Socket Springs.
[0164] Basically, I will introduce some contact springs to work either together with the existing rigid socket middle contact element 31 , or to replace this rigid element altogether.
[0165] The new contact springs can work in the same radial line area as the existing rigid one, as in FIG. 52 ; or it can be located at some relative angular position to it, for example as in FIG. 53 . This is when we look down at the socket from its opening. See FIGS. 52 and 53 , and as in Pictures 4 & 5 . Usually, most of the sockets on the market are built to have the socket center contact spring 23 come from near the rim 47 of the socket towards the center. The socket middle contact element 31 is usually located across from socket center contact spring 23 , i.e. at 180 degrees from it. Most of the proposed new contact springs will be located in the same way. I will call this kind of spring location the “In-Line” arrangement. See also Pictures 4 and 5 .
[0166] However, if the socket has a pull chain actuator built-in, the arrangement is slightly different. In this case, the socket middle contact element 31 can be at 90 degrees with respect to the socket center contact spring 23 . This can be beneficial. We can take advantage of this “acceptable” arrangement and do the same thing with our new proposed contact springs. I will call this kind of spring location the “Offset” arrangement, as in FIG. 53 ?.
Preferred Embodiments
Socket/Spring Embodiment #1
[0167] FIGS. 9 and 10 show a new contact spring 101 . This can work either in conjunction with the existing socket middle contact element 31 , or it can replace it. FIG. 9 gives the general picture or configuration, while FIG. 10 gives a close-up view.
[0168] I will repeat this same approach in many of the following embodiments. The first figure will show the general picture or configuration of the new proposed contact spring, while the second figure will give a close-up view.
[0169] I will also describe al the new springs in more detail at the notes below and at the end of this overview.
Socket/Spring Embodiment #2
[0170] FIGS. 11 and 12 show a second contact spring 102 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Notes re Embodiments #1 and 2
[0171] In both these two embodiments, the spring is on the left side or “inside face” 117 of the main body 111 of socket middle contact element 31 . The new spring can be a new additional one, or it can be an integral part of the existing switch middle wiper 45 . Please see FIGS. 9 and 13 for terminology and for the Ref #s.
[0172] I am calling this kind of new contact springs the Group “A” springs.
Socket/Spring Embodiment #3
[0173] FIGS. 13 and 14 show a 3rd contact spring 103 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Socket/Spring Embodiment #4
[0174] FIGS. 15 and 16 show a 4th contact spring 104 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Socket/Spring Embodiment #5
[0175] FIGS. 17 and 18 show a 5th contact spring 105 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Socket/Spring Embodiment #6
[0176] FIGS. 19 and 20 show a 6th contact spring 106 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Socket/Spring Embodiment #7
[0177] FIGS. 21 and 22 show a 7th contact spring 107 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
Notes re Embodiments #3 through 7
[0178] In all the embodiments #3 through 7, the spring is on the right side or outside face 118 of the main body 111 of socket middle contact element 31 . The new spring can be a new separate additional one, or it can be an integral part of the existing main body 111 of socket middle contact element 31 , if it is possible to do so. Please see FIGS. 9 and 13 for terminology and for the Ref #s.
[0179] I am calling this kind of new contact springs the Group “B” springs.
[0180] With group B springs, I am proposing to make a change in the base 131 of the socket, which is the insulating body, which carries the springs and other components shown in the figures. I propose to increase the width of the slot 133 in FIG. 9 , which holds the existing main body 111 of socket middle contact element 31 and the switch middle wiper 45 , so that the new spring(s) would fit in the same, though enlarged slot 135 in FIG. 13 . This can be seen in FIGS. 13 through 22 .
Notes re ALL the Above Embodiments
[0181] As I said at the beginning of this section, we can have at least two different arrangements for the new contact springs. The “In-Line” arrangement or the “Offset” arrangement.
[0182] If we look at the drawings closely, we will notice that the new contact springs are drawn on top of the socket middle contact element 31 , which may give the impression that there would be some kind of interference between the two. The answer is two-fold.
[0183] If the new springs are “Offset”, then there is no interference. The drawing is simply showing them together, but in reality they are located at two different “radial” position with respect to each other. See FIG. 53 .
[0184] But it is possible that we might decide to place them in the same radial location, i.e. using the “In-Line” arrangement, as in FIG. 52 .
[0185] I will show next, how to handle both cases.
[0000] Offset Arrangement
[0186] FIGS. 23 through 27 show the new contact spring # 7 (Ref # 107 ), which was shown in FIGS. 21 and 22 . The figures show the spring, looking at it from various viewpoints. I have done this, to help the reader better visualize the shape of the spring.
[0187] This would be the shape of the spring, if it is located in an “OFFSET” arrangement, as in FIG. 53 , and there would be no interference between it and any of the other existing contact elements of the socket.
[0188] However, if we want to “co-locate” the new spring together with the socket middle contact element 31 , as in FIG. 52 , or more accurately, with the “STOP” portion 112 of the socket middle contact element 31 , i.e. in an “IN-LINE” arrangement as in FIG. 52 , then we would do something like in FIGS. 28 through 40 .
[0189] FIGS. 28 through 30 show the new contact spring, together with the existing switch middle wiper 45 and the socket middle contact element 31 , viewed from various angles and viewpoints. FIG. 28 shows the viewing angles, i.e. 0°, 30°, 60°, . . . up to 330°, to have a total of 12 views. FIG. 31 shows an enlarged view of some of the figures in FIG. 29 . And FIGS. 32 through 40 show the same set of springs, but again enlarged even more, to be able to discern as many of the details as possible.
[0190] I have given Ref #s to the particular portions of the socket middle contact element 31 , and shown them in FIG. 21 . They are:
[0191] Ref # 31 is the whole middle contact element of the socket, including all the following portions.
[0192] Ref # 111 is the main body of socket middle contact element 31
[0193] Ref # 112 is the top tip, which touches the middle contact ring 3 of the bulb
[0194] Ref # 113 is the “boss”, which accepts the switch middle wiper 45 . It looks that it is “coined” out of the main body 111 .
[0195] Ref # 114 is the coined recess behind the boss 113 .
[0196] Ref # 115 is the new boss, which will accept the new proposed springs, as per this invention. It, too, could be coined, like the boss 113 .
[0197] Ref # 116 is the new coined recess behind the new boss 115 .
[0198] Ref # 117 is the left hand side face of socket middle contact element 31 , or the “inside” face.
[0199] Ref # 118 is the right hand side face of socket middle contact element 31 , or the “outside” face.
[0200] In FIGS. 32, 38 and 40 , I have used the above Ref #s to clarify the views, as much as possible.
[0201] The key point in all these figures is to show that the old/existing elements have been slightly changed to adapt to the new situation. And the new spring is shaped to be able to “co-habitate” with the modified old elements.
Socket/Spring Embodiment #8
[0202] FIGS. 41 through 46 show an 8th contact spring 108 . Again, this can work either in conjunction with the existing socket middle contact element 31 , or it can replace it.
[0203] The main new feature here is the double pronged shape of the top portion 141 of the new spring. Here, the new spring “straddles” the “stop” 112 of socket middle contact element 31 , but without touching it or rubbing against it. The main purpose of this feature is to protect the new spring and to prevent it from getting distorted when the bulb is threaded in or out of the socket.
Socket/Spring Embodiment #9
[0204] Picture 4 shows two sockets. The socket 91 on the LHS (left hand side) shows a conventional present state of the art socket. The socket 93 on the RHS (right hand side) shows an embodiment of the present invention.
[0205] We can see in the conventional socket 91 the parts that were described earlier, for example, the socket center contact spring 23 , the rigid socket middle contact element/stop 31 and the socket threaded shell 27 . The socket 93 on the RHS of the picture shows the same components as the conventional socket 91 on the LHS. However, we can also see in it the new component that was added. It is the new contact spring 95 , which sits near the rigid socket middle contact element 31 .
[0206] Picture 5 shows a close-up view of the same improved socket 93 , which was shown on the RHS of picture 4 . You can also see that the socket threaded shell 27 has also been modified slightly. Some metal has been removed from the area 97 , to ensure that the new contact spring 95 does not touch any part of the socket threaded shell 27 , so as to avoid any electrical connections between the new contact spring 95 and the socket threaded shell 27 . Compare the area 97 with its corresponding area 99 in the conventional socket 91 in picture 4 .
[0207] I would like to call this my SOCKET/SPRING EMBODIMENT #9.
[0208] The spring 95 is similar to all the other new springs proposed in the previous embodiments #1 through 8, from the point of view that it can sit near the socket middle contact element 31 , and actually can co-locate with it. We can do one of at least two things. One is to enlarge the slot 133 ( FIG. 9 ) to look like the enlarged slot 135 in FIG. 13 , and then place the new spring 95 adjacent to the socket middle contact element 31 . Or two, we can shave off some material from main body 111 of socket middle contact element 31 , enough to equal at least the thickness of the new spring 95 and then fit both the main body 111 and the new spring 95 in the same existing slot 133 , without modifying it. I chose the second alternative when I built my prototype shown in pictures 4 and 5 .
[0209] Picture 6 shows two enlarged views of the new spring 95 . I simply placed the spring on the platen of a scanner and scanned its picture into the computer. The view on the LHS is the spring laying flat on the platen of the scanner. The view on the LHS is an end view of the spring. I place the spring between two rubber erasers to hold it upright on its edge and then scanned the image.
[0210] Picture 7 shows the various components that go into a 3-way socket, plus the additional parts, 95 and 96 , that I have used to build my prototype shown in Pictures 4 and 5 . The parts are usually held together by the rivets 98 . When I disassemble the socket, I had to destroy these rivets 98 , and I used the “screws and nuts” 96 shown in the picture. Then I filed the main body 111 of the socket middle contact element 31 by about 0.010″, which is the thickness of the new spring 95 . Then I place both the new spring 95 and the socket middle contact element 31 in the slot 133 of the socket base 131 , and reassembled the socket as seen in pictures 4 and 5 .
Review and collection of Preferred Embodiments of Inventions Related to Sockets
[0211] I would like to summarize the main basic concepts that represent the inventions related to sockets as follows:
[0000] #S 1 . A Socket with the Middle Contact is a Spring.
[0212] A socket for use with 3-way electrical light bulbs, hereinafter referred to as bulb, where said socket is comprising a center contact spring, a middle contact element and a threaded shell, which is adapted to accept said bulb, and where said bulb comprises a center contact point, a middle contact ring and a threaded base, which is adapted to fit inside said socket threaded shell, and where said bulb comprises also a connection means that connects said middle contact ring with one of the filaments inside said bulb, wherein said middle contact element of said socket is flexible and can act as a spring.
[0213] #S 2 . A Socket that has an Additional Member that Would Act as a Stop
[0214] A socket as in # 1 above, wherein said socket has another element that acts as a stop to limit how far said bulb can be threaded inside said socket.
[0000] #S 3 . A Socket that has the Middle Contact & the Stop Near or Straddling Each Other.
[0215] A socket as in # 2 above, wherein said middle contact element of said socket and said stop of said socket are near each other or even straddling each other.
[0000] #S 4 . A Socket that has the Middle Contact & the Stop not Near each Other.
[0216] A socket as in # 2 above, wherein said middle contact element of said socket and said stop of said socket are not near each other.
[0000] #S 5 . A Socket that has the Shell with Proper Electrical Clearance for the New Spring.
[0217] A socket as in # 1 above, wherein said shell of said socket is shaped so as to provide enough clearance between it and said middle contact element so as not to have electrical contact between said shell and said contact.
[0000] #S 6 . A Socket that has the Shell with Proper Electrical Clearance for both the new spring and the Stop.
[0218] A socket as in # 2 above, wherein said shell of said socket is shaped so as to provide enough clearance between it and said middle contact element and said stop so as not to have electrical contact between said shell and said contact or between said shell and said stop.
[0000] GROUP TWO: Inventions Related to Bulbs.
Notes
[0219] 1. The inventions here spill over to Group Four, which are related to Inserts, Adapters and the like. Some of the parts that can be used for Group 2 can also be used for Group 4 and vice versa. I will point to that as I go along.
[0220] 2. The five drawings in FIGS. 47 through 51 , which I am using for both Groups 2 and 4 , have a flaw. All these five drawings show the bulb at a higher position than it should be at if it is supposed to work properly. The more correct position is shown in FIGS. 66A, 66B , 67 A and 67 B. The flaw in FIGS. 47 through 51 is that, the socket middle contact spring 23 is shown as if it has not been compressed at all. In fact, it looks like as if the bulb middle contact point 1 has not even touched that socket middle contact spring 23 . All this, while at the same time, the figures show that the flexible conductive doughnut 151 has already touched and is sitting on top of the socket middle contact element 31 . That would not work. I have corrected the situation by doing two things.
[0221] a. In FIGS. 66A through 67B , I selected the dimensions, mainly the thicknesses, of the donuts so that I would make simultaneous contacts at both the socket middle contact element 31 and socket middle contact spring 23 . More accurately, I would first touch and compress the socket middle contact spring 23 to the proper deflection position 66 before I touch socket middle contact element 31 . At this proper deflection position 66 , socket middle contact spring 23 would exert the proper amount of contact force against center contact point 1 of the bulb, so as to provide an acceptable electrical connection.
[0222] b. In order to accomplish this “dimensional” agreement, I had to lower the bulb further down than it was shown in FIGS. 47 through 51 . In turn, to accomplish this, I deleted the part of the socket shell 27 , which showed the thread. The reason is because I could not show both threads, that of the bulb and that of the shell, in the same configuration as in all the other drawings, and at the same time show the bulb at the height that was required. I could draw the bulb at the elevation of one thread pitch or at one pitch higher or one pitch lower. That would be either too high or too low. I needed to “turn” the bulb a portion of a full turn, e.g. a quarter of turn or two thirds of a turn for example to reach the desired height. That would have been a little more difficult to show on the drawing. So, to make it easy on myself, I simply did not show the thread of the socket shell. Please note that this effect of the location of the thread and the height of the bulb is very important and it is one of the reasons, that the solder spot 19 would sometimes hit the socket middle contact element 31 and at other times it would not. If we could control the starting point of the thread helix of the socket thread and that of the bulb thread, then we would be able to control the end resting position of the solder spot 19 and we would eliminate all of our headaches. This will be the basis of the inventions in Group 4 .
Preferred Embodiments
BULB Embodiment #1—Changes to the Bulb Itself
[0223] The bulb could be manufactured from the beginning on by the manufacturer, such that there would be no irregularities in the shape of the solder/connecting spots 19 , e.g. no ups and down and no sharp interruptions in elevation, no bumpiness and no level differences between the socket middle contact spring 23 and solder spot 19 outer surfaces. There are at least two conceivable ways to accomplish that goal.
Embodiments 1-a
[0224] One is to first create an indentation in the bulb middle contact ring 3 , where the solder spot 19 is expected to be located. Then after the soldering operation is completed, and the solder spot has filled that indentation and probably has overflown the space, then the outer surface of the solder spot would be sanded or otherwise worked/machined, so that its outer surface would be smooth and flush with the surrounding surface of the bulb middle contact ring 3 .
Embodiments 1-b
[0225] The second way is to keep the present situation as is, and then during the operation of creating the solder spot 19 , the solder would be smoothened and rounded and tapered so as to gradually join the level of the adjacent surfaces of the bulb middle contact ring 3 . If necessary, then some solder or appropriate material could be added to the contact ring 3 , to create a smooth transition between its surface lever and the outer surface of the solder spot 19 . This however, would probably make the contact ring slightly “out of round”. It may not work with the rigid socket middle contact element 31 , but it could work nicely with the “springy” contact elements that I am proposing in this present invention.
BULB Embodiment #2—Add-ons to the Bulb
BULB DOUGHNUT # 1 -1-layer, compressible. ( 151 )
[0226] FIG. 47 shows a doughnut 151 that is applied to the bottom of the bulb, at the area of the bulb middle contact ring 3 . This is not to scale. The thickness of the doughnut is shown exaggerated, just to highlight it. In reality it could be somewhere from a few thousands of an inch thick, all the way up to ⅛ of an inch thick. The proper thickness would depend on the chosen material, its flexibility, durability, compressibility, etc. Also the conductivity of the material is important.
[0227] FIGS. 48 and 49 show the same thing, but in enlarged views.
[0228] FIGS. 54 and 55 show the bulb with the donut, outside of the socket. Socket not shown.
[0229] FIG. 56 shows the donut by itself, in top view, side view and in cross-section view.
[0230] Pictures 8 and 9 show isometric views of the donut, from different viewpoints.
[0231] The donut should be made of a material that is relatively compressible, so that the uneven surfaces of the solder spot 19 could dig into it, as shown at point 153 in FIG. 49 , yet at the same time, the material should be firm enough and electrically conductive to make good electrical contact with solder spot 19 . Examples of materials that could be used here are conductive polymers or conductive elastomers, or even something like a steel wool, but made of a good electrically conductive material like copper, brass or bronze. A material like the latter is being used to make electrical connectors. The lower surface 155 of the donut should be smooth and uniform and firm enough to make good contact with the socket middle contact element 31 .
BULB DOUGHNUT # 2 -2-layers: 1.compressible, 2.hard. ( 161 )
[0232] FIGS. 57 and 58 show a similar donut as donut # 1 (Ref # 151 ) except that it is made out of two layers. This was not included in the PPA, Ref 1 . I will refer to it as the 2-layer donut 161 . The first layer 163 is made of a material similar to the one used for donut 151 , i.e. compressible, conductive, etc., but the second layer 165 is made of a material that is harder, like for solid sheet of copper, brass or bronze, formed to the proper shape. The two layers would be properly joined or laminated to form a good electrical connection between them. Layer 163 is positioned towards the bulb, to absorb any irregularities at the bulb, e.g. the irregular solder/connection spots 19 . Layer 165 is positioned towards the socket middle contact element 31 . Layer 165 should be a comparatively harder material than the softer layer 163 . This hard layer 165 would also have a smooth uniform surface. Thus when it sits on top of the socket middle contact element 31 and is rotated around, when the bulb is being threaded inside the socket, there would be no bumps or irregularities to disturb the interconnection between it and the socket middle contact element 31 .
BULB DOUGHNUT # 3 —3-layers: 1.compressible, 2.hard, 3.less hard. ( 167 )
[0233] A third way to make such donuts is to add a third layer at the bottom of the second hard layer described in donut # 2 above. The purpose of this third layer is for it to work better and to cooperate with the socket middle contact element 31 . The socket middle contact element 31 would have an easier time to dig into this third layer and to make a “stable” connection, which I would call a “locked-in” connection, as I had explained elsewhere in these specifications. I did not feel that I needed to make a special drawing for this version. The reader can easily visualize it from my description here. But if the Examiner prefers, I would gladly provide a drawing for it. Although there is no drawing for this version, I will still give it a reference #. It will be the 3+layer donut 167 .
BULB DOUGHNUT # 4 —Substitute
[0234] The doughnut could be replaced by a “paint” or “putty” or the like, that would be applied directly to the bulb at the proper location, i.e. on the bulb middle contact ring 3 . The paint could be “thick” enough to cover the uneven connection/solder spots 19 and to create a smooth surface at the area of the bulb middle contact ring 3 .
BULB DOUGHNUT # 4 —with Insulation Ring, 1-Layer. ( 171 )
[0235] FIG. 50 shows a new “ringed” donut 171 . It uses the previous donut 157 , but adds to it the insulating ring 173 ,as shown. I will refer to this combination of 151 together with 171 , as the ringed donut 173 . FIGS. 59 and 60 show a similar ringed donut 173 , attached to a bulb 13 . FIG. 61 shows the ringed donut 173 by itself, in top view, side view and in cross-section view.
[0236] Pictures 10 through 12 show isometric views of the ringed donut 173 .
BULB DOUGHNUT # 5 —with Insulation Ring, 2-Layers
[0237] FIGS. 62 and 63 show yet another embodiment. It is a 2-layer ringed donut 181 . It consists of a two-layer donut 161 , like the 2-layer donut 161 described earlier, but it is surrounded by the insulating ring 171 .
BULB DOUGHNUT # 6 —with Insulation Ring, 3+-Layers
[0238] I guess the reader can also visualize that we could make another donut like the above one, but using the 3-layer donut 167 , together with a similar insulating ring 171 . I will refer to this one as the 3-layered ringed donut 177 , although I do not have a drawing for it.
[0000] Notes re all the Above Donuts.
[0239] The whole idea of these donuts here is to provide a cushiony interface between the bulb and the rigid middle contact element 31 of the socket, thus “covering up” the irregularities of the solder/connection spots 19 of the bulb and presents a smooth regular surface to the socket middle contact element 31 .
[0240] Of course, there are certain criteria that such a doughnut must satisfy. I have touched on some of that earlier, but I would like to recap here.
[0241] First, it must have the necessary elasticity or compressibility, but at the same time, it should withstand the wear and tear and friction that will be expected when the bulb is threaded in or out of the socket.
[0242] Second, it should not touch the other contact elements of the socket or of the bulb. Otherwise, it may cause an electrical short and defeat the purpose. For this reason, the insulating ring 171 shown in the figures is provided.
[0243] The shape of the doughnut is optional, as long as it provides the conductive elasticity or compressibility and satisfy the other requirements. But since it is supposed to mainly cover the bulb middle contact ring 3 , then the most obvious shape would be a ring/donut with almost the same inner and outer diameters.
[0244] Some possible material for this doughnut could be conductive (filled) polymers or elastomers, as stated earlier.
Review and Collection of Preferred Embodiments of Inventions Related to Bulbs
[0245] I would like to summarize the main basic concepts that represent the inventions related to bulbs as follows:
[0000] #B 1 . Bulb with its Connection Spot(s) Flush.
[0246] An electrical light bulb, comprising a base, which in turn comprises a contact ring, having a connection means, where said connection means connects said contact ring to a filament inside of said bulb, whereby said connection means of said bulb is made flush with the surface of said middle contact ring of said bulb.
[0000] #B 2 Bulb with a Transfer Means to its Middle Contact Ring.
[0247] An electrical light bulb, comprising a base, which in turn comprises a contact ring, and where said contact ring is adapted to make electrical contact with outside contact elements, wherein a transfer means is provided between said middle contact ring of said bulb and said outside contact elements.
[0000] #B 3 Bulb with a Transfer Means to its Middle Contact Ring and Solder Spots.
[0248] An electrical light bulb, as in #B 2 , wherein said contact ring, further comprises one or more uneven connection means along the surface of said contact ring, and where said uneven connection means are connected to a filament inside said bulb, and wherein said transfer means is provided between said middle contact ring of said bulb and said uneven connection means on one side and between any outside electrical contact element that may come in contact with said ring or uneven connection means.
[0000] #B 4 . Bulb with its Transfer Means being a Pliable Conductive.
[0249] An electrical light bulb, as in #B 3 , wherein said transfer means is made of a pliable compressible conductive material.
[0000] #B 5 . Bulb with its Transfer Means being Pliable Conductive and Insulated.
[0250] An electrical light bulb, as in #B 3 , wherein said transfer means is provided with means to prevent said transfer means from electrically touching undesirable surfaces.
[0000] #B 6 . Bulb with its Transfer Means Shaped as a Donut.
[0251] An electrical light bulb, as in #B 2 , wherein said transfer means is shaped like a doughnut.
Bulb Insert/Adapter Embodiment #3
[0252] FIG. 51 shows another similar doughnut, also with an insulating ring around it, but the insulating ring 195 is shaped to more closely conform to the shape of the bulb and the socket. It slides freely up and down inside the socket threaded shell 27 , and comes to rest on top of the socket middle contact element 31 , and hugs the bottom of the bulb. It acts as a guide, to guide the donut inside the socket and to locate it properly in place, e.g. to prevent it from sliding out of position or from tilting too far out of line.
[0253] The insulating ring 195 shown in FIG. 51 does not need to fit tightly against the bulb. It can have enough clearances, to ensure that the real contact would occur at the right spots, again that means at the bulb middle contact ring 3 .
[0000] GROUP THREE: Inventions Related to Systems.
[0254] As I had mentioned under POTENTIAL PROBLEM SOURCES, I had discovered basically THREE potential sources for the problem:
1)The bulbs have a problem, but by themselves and on their own, they are OK. 2) The sockets have a problem, but by themselves and on their own, they are OK. 3) The system, or the combination of, using such bulbs and sockets creates problems. It is mainly the orientation or correlation of the threads in the bulbs and sockets together with the presence of the solder spot 19 of the bulb that create the problems.
[0258] The inventions in Groups 1 and 2 would take care of most of the weak points inherent in the sockets and in the bulbs. But there are still other features that would become relevant, only when we combine a bulb together with a socket, i.e. when we mate a bulb and a socket, by inserting the bulb into the socket. This would then be creating what is considered a “system”.
[0259] Here are some ways to reduce the possibilities of problems with such systems.
[0260] The main goal here would be to ensure that we do not get the solder spots 19 to clash with the socket middle contact element 31 . If we do some of the improvements/embodiments suggested above, then we would not need to do any of the following ones. But, if we ignore the above suggestions, then the following ones may come to the rescue. Basically, we want to avoid getting the unstable contact conditions that I described earlier.
[0261] So, here are a number of suggested embodiments to accomplish this goal:
Preferred Embodiments
[0262] Use a bayonet type of mating feature, instead of threads, i.e. push and twist, as in FIG. 70 , and have 2 contact points, instead of one center point and a ring, i.e. replace the ring by a point.
[0263] Here the contacts for the two filaments could be at the bottom and the return would still be at the side of the base. The two pins that would hold the bulb in place inside the socket, would be located at some different height to make sure that the bulb would go into the socket in the proper orientation.
[0264] FIG. 71 is another embodiment. The contact “ring” is on the side of the bulb base. The socket middle contact spring would touch that ring, but the solder spot 19 would be higher than the middle contact spring, or since we are using the bayonet approach here, then the solder spot could simply placed at a different angular position away from the socket middle contact spring.
[0265] FIG. 72 is yet another embodiment. It is similar to the one in FIG. 71 , except that here we would have a thread instead the bayonet. Here we definitely need to have the solder spot higher than the socket middle contact spring.
[0000] Orbit of Solder Spots 19 does not Coincide with Orbit of the Socket Middle Contact Element 31 .
[0266] FIG. 73 shows the bulb almost identical to the standard conventional bulbs, except that we make sure here, that the solder spot is located at a different “orbit” than that of the socket middle contact element 31 . The socket middle contact element 31 would touch bulb middle contact ring 3 along the orbit circle C 1 , but the solder spot would be located at any point along the orbit circle C 2 . The radius R 1 of C 1 would be smaller than the radius R 2 of C 2 , so then the solder spot 19 would never come close to the socket middle contact element 31 and would never touch it. This means that we would not get that undesirable unstable contact between the socket middle contact element 31 and solder spot 19 , which was described earlier above.
[0267] FIG. 74 shows an embodiment that is slightly different yet. Here the solder spot is at a totally different location than the bulb middle contact ring 3 . So, there would never be any clash between the two.
[0268] Proper Orientation and Location of the threads and of solder spot, to avoid collision of solder spot 19 and the socket middle contact element 31 . What I mean here is ensure that when the bulb is treaded in the socket and is fully seated, the solder spot 19 would never touch the socket middle contact element 31 , actually would not be even near it. This would need that the threads on both the socket shell and on the bulb base are designed and manufactured to accomplish that end goal. For example by starting and ending the thread at certain points on both the sockets and by locating the solder spot always in a certain relation to the thread on the bulb base. It can be done, but would need special attention in manufacturing same. This can be done on an individual basis, i.e. a matched set, each set consisting of one bulb and one socket. This is obviously extremely expensive and impractical (Rolls Royce approach).
[0000] Do the same orientation and location of threads and of solder spot, but for all the bulbs and all the sockets, so as to ensure interchangeability. (Ford approach, or generic Mass Production approach).
Review and Collection of Preferred Embodiments of Invention Related to Systems
[0269] I would like to summarize the main basic concepts that represent the inventions related to SYSTEMS as follows:
[0270] T 1 . System: Bulb & Socket, Where Spot does not Touch or Comes Near Contact. [No Thread] [e.g. FIGS. 70 and 71 ]
[0271] A system comprising a 3-way light bulb, hereinafter referred to as bulb, and a 3-way light socket, hereinafter referred to as socket, wherein said bulb comprises a base, which in turn comprises a bulb middle contact, having a connection means 19 , where said connection means connects said bulb middle contact to one of the filaments inside said bulb, and where said socket comprises a shell and a socket middle contact where said shell of said socket is adapted to accept said base of said bulb, and said socket middle contact is adapted to make physical and electrical contact with said bulb middle contact whereby said socket shell and said bulb base are so designed and manufactured, that when said bulb with its said bulb base is inserted into said socket in said socket shell and is fully seated, then said connection means of said bulb will not touch, actually will not be near enough to touch said socket middle contact.
[0272] T 2 . System: Bulb & Socket: >>Spot Not Touch or Near Contact. [Orbit No Thread]
[0273] A system, as in T 1 , wherein the location of said connection means of said bulb and the location of said socket middle contact are such that during the insertion and mating of said bulb into said socket, the path of said connection means of said bulb will not intersect the path of said socket middle contact, so that said connection means of said bulb will not make touch said socket middle contact during said insertion and mating process.
[0274] T 3 . System: Bulb & Socket: >>Spot Not Touch or Near Contact. [Orbit with Thread]
[0275] A system, as in T 1 , wherein said bulb base is threaded, so as to be threaded into said socket shell, and said socket shell is also threaded, so as to accept said threaded bulb base, and wherein said thread of said socket shell and said thread of said bulb base are so designed and manufactured, that when said bulb and said bulb base is inserted into said socket and said socket shell and is threaded in all the way until fully seated, then said connection means of said bulb will not touch, actually will not be near enough to touch said middle contact element of said socket.
[0276] T 4 . System: Bulb & Socket: >>Thread Orientation of Bulb & Socket and Location of Spot >>Spot Not Touch or Near Contact. [Matched Set] [e.g. FIGS. 72 - 74 ]
[0277] A system as in T 1 , wherein the disposition, i.e. location, orientation, etc., of said thread of said shell of said socket with respect to said middle contact element of said socket and the disposition, i.e. location, orientation, etc., of said thread of said bulb base with respect to said connection means on said middle contact ring of said bulb are such, that when said bulb is inserted into said socket and is threaded in all the way until fully seated, then said connection means of said bulb will not touch, actually will not be near enough to touch said middle contact element of said socket.
[0278] T 5 . System: Bulb & Socket: >>Thread Orientation of Bulb & Socket and Location of Spot>>Spot Not Touch or Near Contact. [Generic, Mass Production, Interchangeability]
[0279] A system as in T 1 , wherein the disposition, i.e. location, orientation, etc., of said thread of said shell of said socket with respect to said middle contact element of said socket is kept the same within all sockets of this kind, and wherein the disposition, i.e. location, orientation, etc., of said thread of said bulb base with respect to said connection means on said middle contact ring of said bulb is kept the same within all bulbs of this kind, whereby when any such bulb from said kind of bulbs is inserted into any such socket from said kind of sockets and is threaded in all the way until fully seated, then said connection means of said bulb will not touch, actually will not be near enough to touch said middle contact element of said socket.
[0000] GROUP FOUR: Inventions Related to Adapters or Inserts.
[0280] I have already talked earlier about two groups of such adapters or inserts, when I talked about the improvements to “bulbs”.
[0281] Here I want to add one third group of such devices.
Preferred Embodiments
[0000] Adapters or Inserts with a GUIDE.
[0000] Guided Donut 191
[0282] FIG. 51 shows a guided donut 191 . It is composed of a conductive center 193 , and an outside insulating guide 195 . The conductive center 193 can be identical to the flexible conductive doughnut 151 described above. The outside insulating guide 195 surrounds conductive center 193 and has a number of functions and properties. First, it prevents conductive center 193 from making electrical contact with surfaces other than the intended bulb middle contact ring 3 . Second, it guides 193 within the socket shell 27 , preventing the whole device from straying out of position or from tilting out of line. It glides up and down, with enough clearance between it and the socket shell so as not to bind, and has enough clearance between it and the bulb base, so as to allow all the contact function to work without loss of contact force.
[0283] FIG. 64 shows the same guided donut 191 , hugging the base of the bulb 13 . FIG. 65 shows the guided donut 191 by itself, in top view, side view and in cross-section view.
[0000] Guided Donut 201
[0284] FIGS. 66A and 66B show a guided donut 201 . It is composed of a 2-layer conductive center 203 , and an outside insulating guide 205 . The 2-layer conductive center 203 can be identical to the two-layer donut 161 described above. The outside insulating guide 205 is identical to the outside insulating guide 195 .
[0285] FIG. 67 shows the same guided donut 201 , hugging the base of the bulb 13 . FIG. 68 shows the guided donut 201 by itself, in top view, side view and in cross-section view.
[0286] Pictures 13 through 15 show isometric views of the guided donut 201 .
[0000] Guided Donut 211
[0287] FIGS. 69A and 69B show a guided donut 211 . It is composed of a 1-layer hard conductive center 213 , and an outside insulating guide 215 . The 1-layer hard conductive center 213 would be made of a hard metal, such as copper, brass, or bronze, in contrast to the compressible material used for example for doughnut 151 . The outside insulating guide 215 is identical to the outside insulating guide 195 .
[0288] In this case, we do not want that the solder spot 19 dig into the central donut, but they would simply sit on top of the surface of the 1-layer hard conductive center 213 . The rest of the function of this guided donut 211 is identical to the guided donut 191 or 201 .
[0289] Pictures 16 through 18 show isometric views of the guided donut 211 .
[0290] Various Combinations
TABLE 1 A good number of the possible combinations of Adapters or Inserts. DONUTS MUSHY HARD RING GUIDE Combinations: # THIN THICK THIN THICK THIN THICK THIN THICK Thin Mushy 1 2 3 Thick Mushy 4 5 6 Thin Mushy with Thin Hard 7 8 9 Thin Hard 10 11 Thick hard 12 13
[0291] Note: I have used the word “Mushy”, as a short expression, to denote the “compressible conductive material” that is used for the donut.
[0292] A lot of combinations and variations can be thought of, as how to shape those adapters and inserts, and which components to include in each combination. The table above gives a good start as to what combinations are possible. I am sure that we could of a couple more at least.
TABLE 2 The combinations described in these Specifications. Combinations: # Part Ref# Figs. Pictures Thin Mushy 1 151 47, 48, 49, 54, 55, 56 8,9 2 3 Thick Mushy 4 5 171 50, 59, 60, 61 10, 11, 12 6 191 51, 64, 65 Thin Mushy with 7 161 57, 58 Thin Hard 8 181 62, 63 9 201 66, 67, 68 13, 14, 15 Thin Hard 10 11 Thick Hard 12 13 211 69 16, 17, 18
Table 2 shows which of the combinations listed in Table 1 have been included in these Specifications. It also shows the Ref#s of the individual parts, and the Numbers of the Figures that shows these combinations. Also, if any Pictures have been included, then Table 2 shows the number of these Pictures.
[0293] For example, part Ref# 201 represents Combination # 9 . FIGS. 66, 67 and 68 show this part. And Pictures 13 , 14 and 15 shows the part in 3-D.
[0294] I did not feel that I had to show each and every possible combination. I felt rather that the sampling that I have chosen and already included in the present application is sufficient to give the reader the gist of what I am trying to convey, i.e. the many different ways we can solve the problem.
[0000] Notes About the Three Above Bulb Insert/Adapters Embodiments:
[0000] General Notes re Inserts/Adapters
[0295] The doughnuts could be pre-molded or pre-shaped. They could then be sold as part of the bulb, or separately.
[0296] If the donut is provided without the insulators, then it could be attached/glued to the bottom of the bulb, specifically to the bulb middle contact ring 3 , by the manufacturer and sold as an improved bulb. The donut itself could also be sold in the after-market, together with an appropriate glue material, such as electrically conductive glue, so that the end user would first glue the donut to the bulb, before inserting the “modified” bulb into the socket.
[0297] If the donut is sold as an integral part with a proper insulating ring or insulating guide, then the end user would simply install/drop the donut into the socket threaded shell 27 and then would insert the bulb in the socket behind the donut, and then thread the bulb in, until it is seated properly. Thus the donut would be trapped between the socket middle contact element 31 and the bulb.
[0298] Obviously, any of these adapters or inserts could be used in conjunction with the systems mentioned earlier, to enhance the performance of such systems. Systems being a light bulb together with an electric socket.
Review and Collection of Preferred Embodiments of Inventions Related to Inserts and Adapters
[0299] I would like to summarize the main basic concepts that represent the inventions related to Inserts and Adapter as follows. Some of these were included in the group on bulbs.
[0000] A 1 Adapter/Transfer Device: >>Conductor/Washer
[0300] A transfer device to be used in conjunction with an electrical light bulb, hereinafter referred to as bulb, and an electrical socket, hereinafter referred to as socket, said socket being adapted to receive such said bulb, wherein said transfer device comprises a layer of conductive material.
[0000] A 2 Adapter/Transfer Device: >>with Insulator
[0301] A transfer device as in A 1 , wherein said transfer device further comprises an insulating material, to prevent said conductive material from touching and electrically connecting to undesirable surfaces or objects of said socket.
[0000] A 3 Adapter/Transfer Device: >>with Guide
[0302] A transfer device as in A 1 , wherein said transfer device further comprises a means, to guide said transfer device inside said socket to locate it properly in place, e.g. to prevent it from sliding out of position or from tilting too far out of line.
[0000] A 4 Adapter/Transfer Device: >>Multi-Layer Conductor, Soft & Hard
[0303] a) A transfer device as in A 1 , wherein said transfer device is made of two or more layers of material, whereby a first layer of pliable compressible conductive material would be located adjacent to said contact ring and any connection means that may be on said contact ring, and where at least a second layer of conductive material, laminated to said first layer, would be located towards said outside contact elements and where said second layer material is harder than said first layer material.
[0000] A 5 Adapter/Transfer Device: >>Conductor, Insulator & Guide
[0304] A transfer device as in A 1 , wherein said transfer device is made of a conductive layer of material, and wherein an insulating material surrounds said conductive material to prevent said conductive material from touching and electrically connecting to undesirable surfaces or objects of said socket, and wherein a means, to guide said transfer device inside said socket to locate it properly in place, e.g. to prevent it from sliding out of position or from tilting too far out of line.
[0000] A 6 Adapter/Transfer Device: >>Multi-Layer Conductor, Soft & Hard, Insulator & Guide.
[0305] A transfer device as in A 1 , wherein said transfer device is made of two or more layers of material, whereby a first layer of pliable compressible conductive material would be located adjacent to said contact ring and any connection means that may be on said contact ring, and where at least a second layer of conductive material, laminated to said first layer, would be located towards said outside contact elements, and wherein an insulating material surrounds said conductive layers, to prevent said conductive material from touching and electrically connecting to undesirable surfaces or objects of said socket, and wherein a means is provided to guide said transfer device inside said socket to locate it properly in place, e.g. to prevent it from sliding out of position or from tilting too far out of line. | The 3-way light bulb has a solder blob on its middle contact ring, where said blob usually has a rough, uneven surface, and frequently does protrude beyond the general surface of the bulb middle contact ring. The solder blob interferes with the conventional socket middle contact element, which is rigid, and prevents the system from creating a good, permanent and reliable electrical connection between the socket and the bulb. Potential flicker and discomfort to the user can occur as a result. Also, the operating life of the bulb as well as the power consumption can be affected. The proposed flexible middle contact spring can alleviate most of these problems. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a division of co-pending U.S. patent application Ser. No. 12/074,772 filed Mar. 6, 2008 and also claims rights under 35 U.S.C. §119(e) from U.S. Application Ser. No. 60/905,637 filed Mar. 8, 2007, the contents of which are incorporated herein by reference.
STATEMENT OF GOVERNMENT INTEREST
[0002] This invention was made with United States Government support under Contract No. W15P7T-05-C-P033 awarded by the Defense Advanced Research Projects Administration (DARPA). The United States Government has certain rights in this application.
FIELD OF THE INVENTION
[0003] The present invention relates to cognitive communications and more particularly to methods of signal processing, communications, pattern classification and machine learning, which are employed to make a dynamic use of the spectrum such that the emanated signals do not interfere with the existing ones.
BACKGROUND OF THE INVENTION
[0004] There are an increasing number of telecommunication services being proposed which, if fully implemented, could use up the allocated frequency spectrum. It is important to be able to provide such services without one service interfering with the other. If a service occupies the same frequency at the same time, there is a possibility of interference between the services which results in spectrum conflicts.
[0005] As will be described, so-called cognitive radios, which may employ software defined radio platforms, are capable of tailoring the transmitted output from the radio. With the advent of software defined radios, it is possible to alter the modulation type, frequency and the time of transmission to guarantee the transmission will not interfere with existing signals. Such radios may be adjusted, for instance, to inhibit transmission during times in which other signals exist. The signals from the software defined radios can also be controlled to emit non-interfering modulation formats. Programs such as the Next Generation (XG) communications funded by the Defense Advance Research Projects Agency (DARPA) propose systems where from radio scene analysis, one finds spectrum holes or White space which defines where signals may be transmitted without interference with other signals. Thus, White space refers to spaces that are not occupied by a signal.
[0006] While such systems create conditions for transmission such that the transmitted signal does not interfere with other existing signals, spectrum utilization with such techniques is somewhat limited.
[0007] As will be discussed, and as part of the subject invention, it has been found that there are so-called Gray spaces where signals only partially occupy the signal space. If it were possible to be able to detect not only White spaces but also Gray spaces, then the spectrum could be more fully utilized, assuming that one could transmit non-interfering signals in the White and Gray spaces.
[0008] Moreover, by analyzing the signal space for existing signals and providing predictors as to the future behavior of these signals, one can accurately predict future White space and Gray space. This permits robust tailoring of the transmitted signals so as not to interfere either with future signals.
[0009] More specifically, as telecommunications equipment evolves in capability and complexity, and Multiple-Input and Multiple-Output (MIMO) and Multi-User Detection (MUD) systems push the system throughput to its limits, it is not going to be too long before cognitive radios will reach the market place (J. Mitola, Cognitive Radio: An Integrated Agent Architecture for Software Defined Radio , Ph. D. Thesis, Royal Institute of Technology, Sweden, Spring 2000; and S. Haykin, “Cognitive Radio: Brain-Empowered Wireless Communications,” IEEE J. Select. Areas Commun ., vol. 23, no. 2, pp. 201-220, February 2005).
[0010] In fact the IEEE 802.22 Working Group (IEEE Working Group 802.22, http://grouper.ieee.org/groups/802/22/, on Wireless Regional Area Networks (“WRANs”)), has been looking to develop a standard for a cognitive radio-based PHY/MAC/air interface for use by license-exempt devices on a non-interfering basis in spectrum that is allocated to the TV Broadcast Service on Wireless Regional Area Networks (WRAN). Ad hoc groups under the Project Authorization Request (PAR) approved by the IEEE-SA Standards Board have started developing a cognitive radio-based PHY/MAC/air interface for use by license-exempt devices on a non-interfering basis in spectrum that is allocated to the TV Broadcast Service. Moreover, cognitive radios will help the commercial as well as the military communication systems, by doing away with the need for comprehensive frequency planning. It is contemplated cognitive radios will be capable of sensing their environment, making decisions on the types of signals present, learning the patterns and choosing the best possible method of transmitting the information. They will be situation aware, and capable of making decisions to ensure error-free and smooth transfer of bits between the users. Cognitive radios will be based on software defined radio (SDR) platforms and will try to understand not only what the users want but also what the surrounding environment can provide.
SUMMARY OF INVENTION
[0011] The present invention makes use of some of the recent advances in cognitive communications in which signal processing, communications pattern classification and machine learning are combined to make a dynamic use of the spectrum such that the emanated signals do not interfere with existing ones or ones projected to exist.
[0012] It is the purpose of the subject invention to conduct a radio scene analysis to ascertain existing signals in the signal space and to predict where the signals will exist in the future. Taking this information, the subject system predicts holes corresponding to White space or Gray space. Then the cognitive radio, or software-defined radio is configured to transmit signals in the unoccupied part of the spectrum which permits increased use of the spectrum. The signal transmission is not limited to the White or the Gray space in the spectrum, but to unoccupied or partially occupied signal space, where the signal space may consist of Space, Time, Frequency (Spectrum), Code and Location.
[0013] In one embodiment the subject system uses signal detection, feature identification, signal classification, sub-space tracking, adaptive waveform design, machine learning and sophisticated prediction algorithms to predict the behavior of existing signals and tailor emitted signals to avoid interference. This can be accomplished by inhibiting transmissions at certain frequencies and at certain times where existing signals are projected to exist; or to change the modulation type at selected times and for selected frequencies.
[0014] The subject system makes use of the Gray space as well as the White space for non-interfering signal transmission. Gray space is a space that is partially occupied by a signal. For example, a Direct Sequence Spread Spectrum (DSSS) signal with a spreading code of 4 chips can accommodate four different users using conventional signal processing techniques. However if only one user is using the network at a time then this forms a Gray space since the given spectrum is only partially used and it can accommodate three more users. Gray space can similarly be defined for other signal types.
[0015] The subject system adapts machine perception and Autonomous Machine Learning (AML) technologies to the autonomous detection and analysis of air interfaces. The underlying premise is that a learning module will facilitate adaptation in the standard classification process, so that the presence of new types of waveforms can be detected, features that best facilitate classification of the previously and newly identified signals can be determined, and waveforms can be generated by using a basis-set orthogonal to the ones present in the environment. Incremental learning and prediction allows knowledge enhancement as more snap-shots of data are processed, resulting in improved decisions.
[0016] In summary, in a method for cognitive communication, conducting radio scene analysis is used to find spectrum holes as well as space for non-interfering signal transmission.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These and other features of the subject invention will be better understood in connection with the Detailed Description in combination with the Drawings of which:
[0018] FIGS. 1( a ) and 1 ( b ) are diagrammatic illustrations showing the cognitive communications system methodology and signal processing flow, wherein signal detection is followed by feature extraction, clustering (un-supervised learning), signal classification into types, machine learning and prediction to understand the time and frequency domain behaviors of the existing signals and based on some decision metrics or policies to transmit the signals in both the White as well as the Gray space so that the new signals do not interfere with the existing ones;
[0019] FIG. 2( a ) is a diagrammatic illustration showing signal detection in Gaussian noise: Top: Time domain waveform of the Bluetooth™ signal heavily buried in noise, Middle: Spectrogram of the same signal, Bottom: Probability that some useful signal is detected for different time segments of the received waveform using Higher Order Statistics;
[0020] FIG. 2( b ) is a diagrammatic illustration showing spectrogram clustering including a scenario where Bluetooth™ and IEEE 802.11b signals are present in the same spectrum, in which spectrogram clustering is used to identify different clusters in a 10 mS frame of data, and in which features are extracted from each of the clusters and fed to the classifier in order to separate the various signals;
[0021] FIG. 2( c ) is a diagrammatic illustration showing the classifier design process;
[0022] FIG. 2( d ) is a diagrammatic illustration showing signal classification based on the extracted features;
[0023] FIG. 3( a ) shows the spectrogram (time and frequency domain behavior) of a 10 mS snippet of a Bluetooth™ signal.
[0024] FIG. 3( b ) is a diagrammatic illustration showing how based upon certain quality factors the best predictor may be chosen from a library of predictors;
[0025] FIGS. 3( c ) and 3 ( d ) are diagrammatic illustrations showing how incremental learning improves the performance of the next time hop predictor for the Bluetooth™ signal with the figures showing that, as more information is available during the incremental learning, the prediction spikes become larger improving the prediction capability, the drawings showing how the incremental learning prediction spikes become larger such that the prediction capability is improved;
[0026] FIGS. 4( a ) through 4 ( f ) are diagrammatic illustrations showing policies and examples of non-interfering signal transmission in the White as well as the Gray space indicating an Existing Signal and a New Signal or Signals, in which in FIG. 4( a ) the classifier detects a Single-Carrier+Non-Frequency Hopping+Broad-band indicating a Direct Sequence Spread Spectrum (DSSS) signal, in which, based on the policy set, a Frequency Hopping Spread Spectrum (FHSS) waveform is transmitted over the entire band; in which in FIG. 4( b ) the classifier detects a Multi-Carrier+Non-Frequency Hopping+Broad-band indicating an Orthogonal Frequency Division Multiplexing (OFDM) signal; in which in FIG. 4( b ) an FHSS signal is transmitted only in the White Space; in which in FIG. 4( c ) non-competitive communications makes use of only as much band-width as it needs making sure that the original FHSS (Multi-Carrier+Frequency-Hopping+Narrow-band) signal is not destroyed; in which in FIG. 4( d ) an example is shown of a competitive signal transmission where prediction information in time as well as the frequency is used to configure a software radio to transmit in all the possible windows that the radio “thinks” are available; in which in FIG. 4( e ) a non-interfering, jam-resistant signal flow diagram is presented; and in which in FIG. 4( f ) a Scenario and Action table is presented for the Physical Layer policy set when the signals and protocols detected and of a known type;
[0027] FIG. 5( a ) is a cognitive jamming flow diagram; and,
[0028] FIG. 5( b ) is a diagrammatic illustration of a scenario and action table for the Cognitive Jamming Physical Layer policy set when the signals and protocols are detected and are of a known type.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] Prior to a more detailed description of the subject invention, through the utilization of cognitive radio, one can both detect the signal environment, predict future signal environments and then tailor the output of the radio's transmitter to provide non-interfering signals. A system for detecting White and Gray spaces becomes increasingly important with the allocation of the VHF band below 700 Megahertz. When this allocation becomes implemented, commercial companies can use it for unlicensed use, for instance, to provide WiFi services. This portion of the spectrum will not be regulated in the sense of being licensed, but rather can be utilized on an unlicensed basis. It, therefore, becomes important that this portion of the spectrum for which primary signals such as TV signals, microphone signals and other signals that might exist be protected by providing cognitive radios to make sure that the existing signals are not interfered with or trampled on. In short, the so-called primary providers or primary users must be protected from interference.
[0030] As mentioned above, cognitive radios are radios that have the ability to sense the environment, and this sensing can occur in two domains. It can be at a physical and lower layer involving physical and medium access control; or it could be at a high level.
[0031] From a physical layer point of view, the minimum capability that the cognitive radio should have is that it should be able to sense the environment, for example, the spectrum, and go into a particular spectrum to try to figure out whether the spectrum is occupied or not occupied. While such capabilities have existed in the past, in the subject invention, one is not just ascertaining whether the spectrum is occupied or not occupied, but rather the system ascertains what exactly the spectrum contains and what kind of signals exist. This is because sometimes one can have certain signals that would indicate that the entire spectrum is occupied and cannot be used. However, it is possible under certain circumstances that the so-called fully occupied spectrum is usable.
[0032] For instance, it may happen that a signal comes on only 10 percent of the time and 90 percent of the time the signal does not occupy the signal space. If one could ascertain the 90 percent quiet time, for instance, by using machine learning and other signal processing algorithms to figure out whether the spectrum is occupied, what kind of signals are present in it, what the behavioral pattern of the signals are, and how the signals may be classified, then the subject invention provides a way for a radio to transmit signals which do not interfere with the existing or projected signals in the signal space.
[0033] For instance, classification of the signals can determine whether these signals belong to a time division multiplex system or a frequency division or code division multiplex system, and from the behavioral pattern, one can predict if one can use the spectrum or not.
[0034] As defined above, White space is defined as a signal space which is completely unoccupied. One can detect the signal space and see whether or not signals exist in that space. If not, White space is detected, and unregulated signals can be transmitted in this space.
[0035] From a physical perspective, if for instance a signal is being projected by a beam forming antenna, the signal might occupy only one portion of a geographical space, but not another. If the beam is utilized to project energy in a given direction, assuming that one could ascertain this, then one could project energy into geographic regions where the beam does not exist.
[0036] The subject system thus depends on three different concepts, namely White space, Gray space and Black space. Black space is a space that cannot be used at all. This is because there is no room for another signal to coexist. The moment one tries to emit a signal in this Black space, one is going to destroy signals that exist there.
[0037] Gray space is a signal space which is partially occupied so there is room for more signals to come in.
[0038] By way of definition as to what constitutes signal space, signal space is basically a multidimensional feature space.
[0039] While systems in the past have concentrated on White space, the subject application introduces the concept of Gray space, which infers that a signal space is not merely spectrum, but is multidimensional feature space consisting of space, time, frequency, code and location.
[0040] By being able to sense this Gray space signal environment, software defined radios determine how it is that signals can either coexist in that space, be multiplexed in that space by employing frequency, code division or time division multiplexing, or use multi-user detection techniques so that the Gray space can be maximally utilized.
[0041] It is the purpose of the subject invention to try to make efficient use of the signal space so as, first of all, to have unblended and structureless communications. It is the purpose of the software defined or cognitive radio to sense a particular environment or signal space and make efficient use of the delivery resources so that one can have assured, unplanned and structureless communications.
[0042] As will be described, part of the subject invention relates not only to the efficient use of the signal space but also for the implementation of cognitive jamming. In cognitive jamming the signal space is detected and characterized such that with the character and predicted nature of the signals being detected, one can design jamming signals that consume a minimal amount of energy and resources.
[0043] Returning now to cognitive communications, signal processing, sensing and signal classification, as well as machine learning, was utilized to figure out the existing signals in a given signal space in terms of what their characteristics are and how they use the space so that one can find what space is available and then use that space. In short, the system finds out a way to communicate using the same signal space.
[0044] How one detects the signal space and predicts the future for the signals that do exist in the space will be described hereinafter. These include spectrum analysis and signal detection utilizing high order statistics. In one embodiment, one first attempts to identify the existing signals by collecting wave forms that are being transmitted in the air, using algorithms first to detect if there is any signal present, and then parsing the samples into structured energy or unstructured energy based on high order statistics. Whenever one finds structured energy, one determines that there is an existing signal. Thus, for every segment of data the system tries to figure out whether it contains some structured energy or not. If it does contain structured energy, it means that the signal has some information, making it an information bearing signal. This means that the probability of a signal being present goes up. The analysis provides the places and times where a signal has occurred and where it is likely to occur in the future.
[0045] Not only does the subject system analyze the time period that the signal occurs, it also looks into the frequency dimension as well. In one embodiment, the signal and time information is combined to form a cluster. The cluster enables ascertaining whether signal chunks belong to the same signal and thus is part of the same signal. With clustering, which is an autonomous process, one can have enough knowledge as to where in time and frequency the signal exists.
[0046] In another embodiment the time and frequency for a certain signal may not be sufficient if it is an a periodic signal. The signal might be a frequency hopped signal. Thus, one must collect enough information to not only know its existence but to predict the future existence. In the present invention this is accomplished utilizing signal classification and machine learning that collects and processes what has already happened so as to predict when it will happen again and be able to tailor the transmission so as not to interfere with a particular behavior.
[0047] Signal classification goes further into the detail of the signal and tries to figure out what kind of signal it is. For instance, one might have a broad band or narrow band signal, one might have a frequency hopping or non-frequency hopping signal, one might have either a single carrier or multi-carrier signal, or one might have a signal which is either broad pulsed or narrow pulsed. Finally one can ascertain through signal classification how many signal types are present.
[0048] The signal classification, for instance, in the case of a frequency hopped signal, indicates where there is going to be a frequency hopped signal. If it is determined to be a frequency hopped signal, one has to be able to detect and predict in a different manner than if it was a simple frequency-stable periodic signal.
[0049] If one has detected a broad band signal that is not frequency hopping, it may nonetheless be a periodic because it exists and then doesn't exist during various time intervals. One, therefore, has to predict its characteristics in a different manner.
[0050] Thus, every class of signal that one finds has to have a corresponding prediction algorithm which is how one is to broadly classify what signals exist and where they are going to be.
[0051] In short, the subject system includes a prediction module that tries to predict the future patterns of the signal, and this is done through initial classification.
[0052] After the initial signal classification, in one embodiment one employs machine learning to predict the Gray spaces. Note that feature extraction clustering and signal classification enables machine learning to accurately make the prediction. Machine learning also includes cluster matching and associative learning and involves multiple predictor pattern matches. In one embodiment, a number of different pattern matches are evaluated.
[0053] In the learning cycle, one does not transmit any information. One rather gathers signals, detects signals from clusters, and parses the information into signal classes.
[0054] The system then uses feature sets in determining whether or not there is Gray space. The ascertation of Gray space includes analysis of bandwidths, time widths, center frequencies of clusters, standard deviations, repetition frequencies and other statistical features often employing high order statistical calculations as well as singular value decomposition.
[0055] Referring now to FIG. 1( a ), what is shown as a block diagram of the subject system in which an input signal 10 is coupled to a clutter suppression module 12 in turn coupled to a signal detection module 14 followed by coupling to a feature extraction module 16 which in turn is coupled to a signal classification module 18 .
[0056] Note that the feature extraction module 16 outputs a feature vector 20 to signal classification module 18 . Feature extraction module 16 is also coupled to a learning and prediction module 22 which in combination with the signal output from the signal classification module 18 on line 24 predicts for a given signal that has been detected where any Gray space may occur.
[0057] The output of the learning and prediction module 22 is coupled to a decision metrics and policies module 24 to control the output of a software defined radio to communicate in either White or Gray space as illustrated at 26 .
[0058] In one embodiment the performance measurement module 28 is coupled to the output of module 26 to measure the performance of the system and to update the learning and prediction module 22 .
[0059] Note that the signal classification module 18 outputs the signal type or types 30 to communications module 26 of the software defined radio so that when a decision is made as to how the software defined radio is to output information, the signal type information is available.
[0060] Referring to FIG. 1( b ), how the system FIG. 1( a ) operates is described in more detail. Note that for the spectrum analysis and signal detection which includes clutter suppression and signal detection modules 12 and 14 is here illustrated at 32 . Waveform 34 shows the original signal, whereas waveforms 36 show the detected signal.
[0061] The purpose of module 32 is to ascertain where the signal occurred in time and frequency.
[0062] In order to ascertain the characteristics of the signal, it is possible using time and frequency to at least understand what band the signal is occupying and how it is occupying the band. This time frequency spectrogram is shown at 38 . The spectrum analysis and signal detection indicates in the waveforms 36 where it is that one does not wish to transmit information.
[0063] Where to transmit and where not to transmit information is defined by policy sets in which the policies are separated into competitive and non-competitive. The non-competitive policy set is a policy set which is rather conservative. It makes sure that it is 100% possible to transmit signals in this region of the signal space because they will not interfere. However, setting a non-competitive policy set minimizes the amount of spectrum that can be utilized.
[0064] The competitive policy set is based on the prediction of where the existing signals will exist and makes use of the prediction so that one can transmit in these regions regardless of the fact of an existing signal.
[0065] Note that from the time frequency detection of module 38 one can through feature extraction and clustering further isolate the existing signals as illustrated at 40 . Note also that here, a Direct Sequence Spread Spectrum (DSSS) is inputted to Module 38 , with the occupied spectrum space illustrated by shading 42 .
[0066] With the feature extraction and clustering, one can isolate the DSSS signal as illustrated at 44 and use this information for the signal classification which has five basic classifications namely: broad band, non-frequency hopping, single carrier, broad pulse, and one signal type. The selected classification of the signal is coupled to learning and prediction module 22 which then determines that one could utilize a narrow band high power frequency hopping signal 46 to coexist with the DSSS signal 48 and 50 . The DSSS signals correspond to code-division multiple access signals, whereby it can be seen that the narrow band high power signal will not significantly interfere with these signals.
[0067] In terms of the ability to communicate in the White and Gray Space, one can see that one can inject signal 52 occupied space 54 , which signals do not interfere with the DSSS at 56 .
[0068] What this shows is that it is possible in one instance with a narrow band high power signal to transmit in the signal space initially occupied at least partially by a DSSS signal.
[0069] What is seen in FIG. 2( a ) is the signal detection stage for another class of signals. For instance, the first signal here illustrated at 60 is narrow band with a fairly small energy such that the signal is buried in noise and can not be detected easily. In 62 , one can see this signal in the frequency domain. Note that in FIG. 2( a ) it is very difficult to figure out exactly where this signal is occurring, meaning that what is presented looks like noise.
[0070] One of the subject algorithms is quite powerful and can basically parse the structured energy from the unstructured energy to figure out where the signal is occurring. Note that the probability of a signal occurring in the spectrogram at the bottom of FIG. 2( a ) shows that signals 64 , 60 , and 66 occur at precise predictable times.
[0071] It can be seen that signal 60 , once obscured, in spectrogram 62 , can be seen using artificial signal processing to enhance the appearance of the signals that are coming in, namely the frequency hopping signals. In the middle spectrogram of FIG. 2( a ), one can see small dots corresponding to a signal detection spike. Thus, wherever a dot has occurred corresponding to the frequency hopping signal, signal detection predicts where the frequency hopped signal has occurred in time and presents this as a highly visible line in the bottom FIG. 2( a ).
[0072] Referring now to FIG. 2( b ), what is shown is clustering and feature extraction. What is shown here is that in the spectrogram 70 the signal is shown with the time domain on the horizontal axis and frequency on the vertical axis, with the clustered points 71 and 72 showing where exactly the signal has occurred. It will be appreciated that one can have multiple dimensions. Therefore, one wishes to have multiple dimensions in which to try and figure out where these signals are occurring and do so in an autonomous fashion.
[0073] Thus, what is shown in FIG. 2( b ) is image processing clustering in the frequency dimension so as to provide a spectrogram of frequency versus time. Note that the image consists of pixels or clusters from which one can see that one has certain pixels that belong to the same signal. Thus, one has a spectrographic way of ascertaining that certain pixels are the result of the same signal.
[0074] Note in this spectrogram there are two signals that are occurring at the same time. First there is a frequency hopping signal shown at 71 , and then there are blocks 72 which correspond to a direct sequence spread spectrum signal.
[0075] As can be seen the block 72 can be further isolated using spectrogram clustering such that the block 72 can be classified on the basis of features such as time width of the clusters, bandwidth of the clusters, center frequency of the clusters, standard deviation of the center frequency of the clusters, statistical features such as the higher order statistics, singular values in a singular value decomposition, time of arrival, time difference of arrival, mean, variance, standard deviation, probability of event occurrence of the various features, raw or processed features, time frequency detection ratio etc. In this particular instance, shown are the maximum bandwidth MaxBW, maximum time MaxTw and center frequencies of the clusters fc are shown by the arrows.
[0076] Having utilized spectrograms in clustering one can determine certain characteristics of the input signal.
[0077] Referring now to FIG. 2( c ), this figure shows a general way in which a normal machine learning and classification stage would work. Here a classifier 80 includes feature measurement 82 followed by a module 84 to make classification decisions such that as illustrated three classes of signals are outputted. It is possible as shown at 86 to score the results and provide feedback over line 88 to a train classifier modules 90 that provides weightings 92 to classification decision module 84 .
[0078] In designing the classifier, as illustrated at 90 , one chooses features 92 and models 94 which are used by module 96 to design the classifier.
[0079] Note that the chosen features are inputted to the feature measurement module 82 as illustrated by line 98 and that design classifier 96 outputs the design classifications on which a decision is made over line 100 .
[0080] What will be apparent from the FIG. 2( c ) machine learning and classification stage is that, for example, on the basis of features such as time width of the clusters, bandwidth of the clusters, center frequency of the clusters, standard deviation of the center frequency of the clusters, statistical features such as the higher order statistics, singular values in a singular value decomposition, time of arrival, time difference of arrival, mean, variance, standard deviation, probability of event occurrence of the various features, raw or processed features, time frequency detection ratio etc. machine learning and signal classification may be carried out.
[0081] In order to detect identify and classify the signal one needs a very powerful feature measurement stage. The feature measurement stage measures all the features because these are the measurement factors which help one to make a decision as to what signals will exist in the future.
[0082] Having decided that the signal has certain features, the output of feature measurement module 82 is coupled to classification module 84 to make the classification decision. The results are scored so that one can understand how well the classification algorithms are behaving. Given this scoring, the system goes back to train the classifiers, making the system an adaptive system.
[0083] The adaptive nature of the classifier may be understood as follows: For instance if one needs one more feature to finally ascertain the character of the incoming signal, the training classifier module 90 provides the additional features to be able to make a more robust classification. Thus, the classifier is adaptive and is able to be trained based on scoring results and the training provided by classifier training module 90 .
[0084] Referring to FIG. 2( d ), what is shown is the result at the end of the classification stage wherein a typical classification stage takes into account different features that are measured. In one embodiment one chooses the carrier frequency, the center frequency of a cluster, the time width and the bandwidth. Note that these features are enough to separate three different protocols namely Bluetooth™, 802.11b, and 802.11g. As can be seen in the feature space of FIG. 2( d ), different signals occupy different regions. Here it can be seen that the Bluetooth™ occupies region 110 whereas 802.11g occupies region 112 and 802.11b occupies region 114 . Thus, one can clearly see that one can separate the signals into three classes and accurately classify these signals.
[0085] Once having classified the signals one can understand the existing signal in a better way and create a new signal in the feature space where the signals do not exist. Referring now to FIG. 3( a ) what can be seen is a spectrogram 120 of time versus frequency for a Bluetooth™ signal which, as can be seen from the pixels 122 , is a narrow band frequency hopping signal. This is a typical spectrogram which when clustering is performed and signal classification is performed, one ascertains what the incoming signal is and how it looks. More importantly it also provides the features for predicting where the signal will exist in the future.
[0086] Referring to FIG. 3( b ) once one has extracted a number of features of the signal, one can give it to a number of predictive pattern matchers. The features are shown at 126 which are coupled to cluster matchers 128 , 130 , and 132 , that are respectively coupled many predictive pattern matchers 134 and 136 , with the outputs of all the predicative pattern matchers coupled to a module 140 which evaluates predictions.
[0087] If upon evaluation of the outputs from the predictive pattern matchers one needs to develop a new pattern this is done at module 142 , this new pattern 144 is installed in the predictive pattern matchers, thus making the cluster matching and pattern matching adaptable.
[0088] Referring to FIGS. 3( c ) and 3 ( d ), these figures show one of the pattern matchers and how they operate. They also show how machine learning takes place over time.
[0089] Note that FIGS. 3( c ) and 3 ( d ) are three-dimensional figures, one axis of which showing the time since the last pulse. This in essence graphs how much time has elapsed since the last pulse.
[0090] The other axis is graphing the time to the next pulse. So if one pulse just occurred, when is the next pulse going to occur in time?
[0091] The vertical axis simply shows how many instances of the feature have occurred. Thus, in FIG. 3( c ) one has a three-dimensional space where there are a number of instances versus certain time characteristics that are graphed.
[0092] It is noted that FIGS. 3( c ) and 3 ( d ) are the same figures over different periods of time and they represent a particular implementation of a predictive pattern matcher.
[0093] In FIG. 3( c ) one can see a very short time duration for the time to next pulse and time since last pulse. After for instance a hundred milliseconds of learning one can clearly start seeing that there are certain spikes that are becoming more and more pronounced. This is because of the pattern which is present inside the signal repetition pattern.
[0094] What the system learns is that there is a certain repetition and that there will be more instances in that repetition. Thus, if a pulse occurs at one point there is a high probability that it will occur for instance at 10 milliseconds later, such that there is a strong correlation set up.
[0095] What is shown by the short time interval of FIG. 3( c ) is that there are a certain number of peaks illustrated in the circle 146 , whereas after a certain amount of time has elapsed as shown in FIG. 3( d ) there is only one peak as shown in circle 148 , making the prediction rather robust.
[0096] FIG. 4( a ) is a diagrammatic representation of how a predictive pattern matcher works and how the machine learning stage works. FIG. 4( a ) shows a number of policy sets. What would be for instance the policy given that one has detected and classified a signal to be of a certain type? For instance, if one has detected a signal which is occurring currently, it may be deduced that the signal is a direct sequence spread spectrum signal. One can then apply two different policies to this direct sequence spread spectrum signal. One policy is that one transmits another direct sequence spread spectrum signal on top of whatever is in the signal space which will not interfere as shown in 48 where the orthogonality is achieved in the code domain. Or for another instance, the new transmitted signal may have a narrow band high power as shown in 46 and may or may not hop in the frequency to create minimum unwanted interference. This is done through the common knowledge that a DSSS signal is resilient to a narrow band interfering signals.
[0097] What is shown is that what is detected is a broad band direct sequence spread spectrum signal here shown at 48 and 50 . This shows that in this particular instance one can transmit a narrow band frequency hopping signal to share the spectrum with the DSSS signal.
[0098] Thus, as can be seen at 150 , signals in this region of the spectrogram do not interfere with the direct sequence spread spectrum signals at 152 . Even if a narrow band high powered signal interferes occasionally with the broadband DSSS as shown in 151 , it creates a limited negative impact to the existing DSSS signal. This spectrogram shows how not just the White Space as shown in 150 , but also the Gray space as shown in 151 is utilized.
[0099] What is shown in FIG. 4( b ) is the detection of an orthogonal frequency division multiplexing system OFDM. The original spectrogram 160 shows the characteristics of this type of signal, whereas the spectrogram in 162 shows that there are regions that are unoccupied by the OFDM signal where a narrow band high power signal, here illustrated at 164 , can be inserted. Note that the OFDM signal is a very popular waveform used in 802.11, WiFi systems or the new WiMax systems. This modulation format is extremely efficient but has certain properties which make it easily susceptible to interference. What happens is that for OFDM signals one divides the entire chunk of bandwidth that one is using into small sub-channels or sub-carriers. While these sub-channels or sub-carriers are extremely efficient, there is a downside in that any interference in the sub-channels can destroy the sub-channel because they are already narrow bands.
[0100] In the subject system, one has the capability to distinguish whether the incoming signal is a single carrier or a multi-carrier signal. If it is a multi-carrier signal, it is most likely an OFDM signal. As will be appreciated orthogonal frequency division multiplexing is just another name for a multi-carrier signal. Further, any OFDM signal being a multi-carrier signal precludes the possibility of transmitting right on top of it. However as can be seen there is gray space even in an OFDM situation.
[0101] How one can transmit over an OFDM signal is now discussed. Due to the broad signal classification one can determine whether the incoming signal is a broad band signal, whether it is a non-frequency hopping signal, whether it is a multi-carrier signal or whether it is a single carrier signal. The system can distinguish between single carrier and multi-carrier signals. If the system finds that the signal is a multi-carrier single doing, clustering ascertains exactly where these signals are present. One can also do machine learning to see how the signal is being transmitted and exactly where it is occurring. While there is no room in the time domain in the above example one can see that there is room in the frequency domain. Thus, one could use frequency hopping not to interfere with OFDM signals.
[0102] While FIG. 4( b ) shows a non-competitive placing of signals, in FIG. 4( c ) what is shown is a competitive transmission. Note that the original signal is a frequency hopper, for instance a Bluetooth™ type signal. Bluetooth™ signals are narrow band frequency hoppers. It hops over perhaps 70 Megahertz. Note that the top diagram shows a spectrogram 166 of the narrow band frequency hopped signals. Note that in spectrogram 166 , blocks 167 show the original signal and blocks 169 show how one could implement the frequency hopping on a non-interfering basis.
[0103] As can be seen by spectrogram 168 , there are regions. or bands 170 and 172 which exhibit very little energy.
[0104] These regions, as can be seen in spectrogram 170 , as relatively broad bands 170 and 172 such that if the transmitted signal occupies only the top and bottom bands, which involve spectrum features not occupied by the Bluetooth™ signal then there is no interference. Also if one transmits another frequency hopper on top of it using machine learning and prediction information then there is no interference.
[0105] FIG. 4( d ) is another scenario involving an instance of even more severe competitive transmission. Note that once again the original signal is a frequency hopper, for instance a Bluetooth™ type signal. Bluetooth™ signals are narrow band frequency hoppers. It hops over perhaps 70 Megahertz. Note that the top diagram shows a spectrogram 188 of the narrow band frequency hopped signals. It will be appreciated that the spaces illustrated by 186 are spaces that in FIG. 4( c ) were not utilized. If one could in fact inject signals at these points one could more completely utilize the spectrum to its fullest extent. Note that spectrogram 182 is the spectrogram of the signal. As in the previous case of FIG. 4( c ), signals are transmitted in the top and the bottom bands 192 and 193 , utilizing the White Space. But in addition, time of arrival prediction information is utilized to transmit more signals in empty spaces as indicated in 186 to make use of the Gray space and hence a greater use of the spectrum.
[0106] Sometimes there is overlap between the new transmitted signal 186 and the original signal 188 . What this shows is that using the suggested technique greater than 90% utilization of the spectrum can be achieved with very little or no interference to the original signal. Going to the top figure, it can be seen that blocks 186 are the places where one could inject non-interfering signals.
[0107] Referring now to FIG. 4( e ), what is shown is a block diagram of the actual logical flow of how a cognitive communication system operates. In this case. the goal of the system is to provide non-interfering transmissions which are not going to jam any existing signals or interfere in any possible way.
[0108] This figure gives a graphical illustration of one embodiment of subject cognitive communications system and in particular shows how it will detect signals, extract features, perform clustering (un-supervised learning), classify the signal in types, learn and predict the time and frequency domain behaviors and based on some decision metrics or policies transmit a non-interfering signal in either White Space or Gray Space.
[0109] In this figure what is presented is a flow chart for non-interfering communications. Starting at box 200 , one activates the sensing operation at box 202 . This is where signal detection occurs, since the first task that the system performs is to identify the signal space in which one wants to operate and to perform spectrum sensing, namely signal detection. Note that there are many different techniques for signal detection based on a number of factors. In one embodiment, higher order statistical signal processing is used for detection of the signals, but one can do initial energy detection as a first cut. Thus, as seen in box 204 , one can use higher order statistical base detection in time and frequency domains, energy detection or covariance and other statistical signal processing-based detection.
[0110] As can be seen at box 206 , a decision is made as to whether a signal is detected. If no signal is detected in any signal space, then one has White Space as indicated at 208 , and one can use any previously agreed-upon method to communicate in this White Space as indicated at 210 .
[0111] On the other hand, if a signal is detected, then one has to ascertain Gray Space as illustrated at 212 . If Gray Space is detected, one has some room left to transmit more information. If one is able to prove that there is sufficient space that is available, then the next thing to be accomplished is to identify the signal type as illustrated at 214 . Signal identification is accomplished by techniques illustrated at 216 to include feature extraction and signal classification. Note that just identifying signal type is not enough. For example, identifying that the incoming signal is a CDMA, direct sequence spectrum signal or OFDM signal is not enough. One needs to understand the protocol in terms of how the signal is occurring and what patterns exist in the signal. This is carried out by using machine learning and prediction as illustrated at 218 involving incremental learning as illustrated at 220 .
[0112] The system understands whether the incoming signals and protocols are of a known type. For instance, there are certain circumstances where one can clearly ascertain, for example, that the incoming signal is an 802.11 signal. It follows certain protocols involving a frame, a downlink, an uplink and a certain pattern. Based on these protocols, one always knows what the signal will look like in the future. The problem then becomes a simple problem because one has already identified that the incoming signal follows a known protocol.
[0113] The fact that a known protocol is indicated at 222 , and having ascertained this, a decision block 224 is invoked to answer the question, “Can the existing system accommodate a new user and is it secure?” If the answer is yes, then as illustrated at 222 the previously agreed-upon method to communicate using a certain type of protocol is invoked.
[0114] However, if the signal is not of a known protocol, then one has to learn what the protocol is. This is based on the utilization of a Scenario and Action Table and discussed in more detail in connection with FIG. 4( f ). However, once the signal is identified and classified, then one can learn where it is going to exist and to be able to transmit in the Gray Space.
[0115] Referring to FIG. 4( f ), a Scenario and Action Table 228 is described. In this table, the system defines the policy sets, namely what is the policy set going to be in order to obtain non-interfering communications. For example, if one identifies that the detected wave form is classified as a direct sequence spread spectrum wave form, the table specifies what the system will do. If the Scenario and Action Table determines that the signal is an OFDM signal, again the table specifies what is to be done. Note, for a DSSS broadband signal, one is able to transmit a higher power signal or another DSSS signal with an orthogonal spreading code. One can also create a frequency hopped signal using an OFDM signal by selectively switching its sub-carriers on or off as time progresses.
[0116] If the signal is detected as an OFDM broadband signal, one finds unused sub-carriers and bands and then transmits in them. Another OFDM signal may be used to fill up the unused sub-channels or the White Spaces.
[0117] If, on the other hand, the detected signals are frequency hopping spread spectrum signals, one performs a time and frequency prediction of the next hop and then makes sure that the transmitted signals occupy one or more time frequency sub-bands that are predicted to be vacant. The system in one embodiment finds the bands that are never used and then occupies them.
[0118] With respect to a time division multiplex signal arriving at the system, one identifies and predicts the temporal holes and transmits in these holes.
[0119] Finally, if a space division multiplex signal is detected, one can use adaptive beam forming to make sure that there are no interfering signals at a particular location.
[0120] Referring to FIG. 5( a ), a Scenario and Action Table is provided for cognitive jamming. The subject system replaces a so-called “dumb” jammer with a smarter jammer. A dumb jammer will have an infinite amount of energy to expend, and it will not try to understand exactly what the signals look like that one is trying to jam or what their protocols are. It will just try to jam the signal with all the power and might that it has. This is obviously a brute force approach.
[0121] However, one can make very efficient use of one's resources. For instance, if one were able to identify what kind of signal is being used in a given spectrum and the protocols that is using, then one can do a smart and targeted jamming operation which in essence saves energy and power. This creates maximum damage at minimum cost.
[0122] It is noted that in some jamming systems deployed on aircraft one does not have unlimited power which is a problem for brute force.
[0123] In FIG. 5( a ), the Scenario and Action Table for cognitive jamming 230 discusses, for instance, what is to be deployed when one detects, for instance, a DSSS broadband signal. In this case, one transmits using a narrowband high power signal on the DC component, one transmits a broadband signal, such as OFDM, to occupy the DSSS bandwidth or one transmits another DSSS signal with the same spreading code. To jam an OFDM broadband signal, one finds the sub-carriers and sub-bands and transmits in them.
[0124] If one is to try to jam a frequency hopping spread spectrum signal, one performs a time and frequency prediction of the next hop and then occupies one or more sub-bands that are predicted to be unoccupied.
[0125] For jamming time division multiplex signals, one identifies and predicts the next time of arrival and transmits any complementary but dissimilar waveform with respect to the original one.
[0126] Finally, for a space division multiplex signal, one performs an adaptive beam steering procedure to target the beam at the receiver and transmit any complementary but dissimilar waveform with respect to the original one to disrupt the communications.
[0127] Finally, referring to FIG. 5( b ), what is shown is a cognitive jamming flow chart. As illustrated at 300 , in order to start the cognitive jamming sequence, one proceeds with spectrum sensing at 302 to find out whether or not a signal is detected. If not, as illustrated by decision block 304 , one ascertains that there is White Space available at 306 , which results at 308 with no jamming action being necessary.
[0128] As illustrated at 310 , techniques for determining the presence of signals include using higher order statistics based detection in time and frequency domains, as well as energy detection and covariance in other statistical signal processing-based approaches.
[0129] Again, if there is a Gray Space, as illustrated at 310 , then one identifies a signal type, as illustrated at 312 , using feature extraction and signal classification techniques, and then, as illustrated at 314 , one understands the protocols associated with the incoming signal to begin using machine learning and prediction using incremental learning, as illustrated at 316 .
[0130] As illustrated at decision block 318 , if there are any signal protocols matched to a known type, one exploits the known vulnerabilities, as illustrated at 320 , and tailors the transmitted signal to jam the detected signal with its known vulnerabilities.
[0131] If the signal type is not known, as illustrated at block 322 , one can transmit any complementary but dissimilar waveform with respect to the original one to jam it in time, frequency, code, space or location. In order to transmit jamming radiation, as can be seen from Scenario and Action Table 324 , selected jamming techniques may be utilized.
[0132] By way of further explanation, experiments have been carried out on simulated data as well as the over the air collected test waveforms of the various devices operating in the Industrial Scientific and Medical (ISM) bands. These devices following a wide variety of standards such as the Bluetooth™, IEEE 802.11b and IEEE 8022.11g were made to transmit and the waveforms were collected and down-converted to base-band using an Agilent 89640 signal analyzer, as is disclosed in IEEE Standard for Wireless Personal Area Networks Based on the Bluetooth™ v 1.1 Foundation Specifications, http://www.ieee 802. org/ 15 /pub/TG 1 .html , IEEE Std. 802.15.1, 2002; and IEEE Standard 802.11 b, g 2003 , Part 11: Wireless LAN Medium Access Control ( MAC ) and Physical Layer ( PHY ) Specifications: Higher - speed Physical Layer Extension in the 2.4 GHz Band ., IEEE Std. 802.11, 2003, the contents of both of which are incorporated herein by reference. The signal analyzer has a bandwidth of approximately 36 MHz which sufficiently covers the spectral foot-print of most signals. The analyzer has 24 digital demodulators with settable center frequency. The center frequency for the digital down-conversion was kept in the center of the ISM band and no prior knowledge of the type of signals present in the spectrum was assumed. The down-converted pass-band waveform samples were subjected to go through the various processes of the cognitive radio functional blocks shown in FIGS. 1( a ) and 1 ( b ). In the subsections each of these blocks and functionalities is briefly described.
[0133] 1. Clutter Suppression and Signal Detection
[0134] The first step for any cognitive radio is to understand the surrounding environment and to detect the ambient signals that are present. Signal detection algorithm must be designed such that it can detect a wide variety of signal types. The two processes that must be carried out to separate the meaningful signal are clutter suppression and signal detection. Clutter suppression may be carried out using sub-space enhancement techniques. Signal detection in Gaussian noise may be carried out using the Higher Order Statistics (HOS) as is disclosed in J. M. Mendel, “Tutorial on Higher Order Statistics (Spectra) in Signal Processing and Systems Theory: Theoretical Results and Some Applications,” Proc. of IEEE, 79(3):278-305, March 1991, the contents of which are incorporated herein by reference. The fact that the cumulants of the order higher than two for a Gaussian process are zero may be used to detect the signals in the Gaussian noise. The received waveform samples may be grouped into segments and higher order cumulants for each of these segments may be estimated. The detection thresholds are defined after a period of learning the distributions of the moments and cumulants, and decision is made whether a particular segment of the received samples contains any meaningful information or not. FIG. 2( a ) shows how signal detection may be carried out in Gaussian noise using HOS. The top figure shows the time domain waveform of the Bluetooth™ signal heavily buried in noise. The figure in the middle shows the spectrogram of the same signal and the figure at the bottom shows the probability that some useful signal is detected for different time segments of the received waveform using HOS. It can be seen that even though the Signal of Interest (SOT) is heavily buried in noise, this signal detection scheme works well with a reasonably good Probability of Detection (PD).
[0135] 2. Feature Extraction and Clustering
[0136] Once a useful signal is detected, feature extraction plays an important role of information assimilation such that the salient characteristics of the signals may be identified and the detected signal or signals may be assigned to appropriate classes. FIG. 1( a ) shows how in a cognitive communications system, feature extraction feeds the signal classification stage and vice-versa. While selecting the features, it is important to keep in mind the questions that one would like the classifier to answer. Some of the questions include
Is it White Space or Gray Space? Is the signal Broad-band or Narrow-band? Is it a Broad-Pulse or Narrow-Pulse signal? Is it a Frequency Hopping or Non-Frequency Hopping signal? Is it a Single-Carrier or Multi-Carrier signal?
[0142] All these questions may be answered using various signal processing methods which involve clustering (un-supervised learning), image processing, mapping, singular value decomposition and other sub-space based tracking techniques on the various forms of the data sets. FIG. 2( b ) shows an example of spectrogram clustering in order to classify the signals that are present in the given spectrum. The example shows both Bluetooth™ as well as the IEEE 802.11b signals operating in the same spectrum. The detected signals in a frame of 10 mS window are clustered into groups. Some of the features are extracted from these clusters in order to separate the signal types operating in the spectrum.
[0143] Many different features may be extracted from the signal however few are useful. Hence it is important to perform sufficient statistics analysis or to optimize the feature set as is disclosed in E. C. Real, “Feature Extraction and Sufficient Statistics in Detection and Classification,” ICASSP—International Conference on Acoustics Speech and Signal Processing , vol. 6, pp. 3049-3052, May 1996; and R. O. Duda, P. E. Hart, and D. G. Stork, Pattern Classification , Wiley's Interscience New York, 2001, the contents of both of which are incorporated herein by reference. Feature optimization will choose the best features from the feature set to separate the signal of interest effectively, whereas sufficient statistics analysis on the feature vector and its distributions will help determine if the existing feature set is sufficient for any new signal or protocol that is detected.
[0144] 3. Signal Classification
[0145] FIG. 2( c ) shows the steps to be followed by the cognitive system to design a classifier. The first step is to develop a model of the system of interest, followed by determination of the key, measurable features. Based on these system aspects, the classifier identifies and characterizes the signal. The classifier itself, regardless of its type, generally consists of a feature measurement phase and a classification phase. The initial weightings or coefficients of the classifier are modified during a training phase based on the classification results against known data. Classifiers can be characterized by the types of algorithms used:
Computational classifiers use definite metrics to separate classes. Examples include a nearest-neighbor and support vector machine. Statistical classifiers estimate classes based on models of what the world of interest looks like. An example are the Bayesian networks, which rely on a priori assumptions. Connectionist classifiers are based on our understanding of how the brain works. The brain consists of a huge number of nerve cells, each of which has multiple connections to other nerve cells. This is a non-linear process. Neural networks (or perceptron networks) use non-linear elements with variably weighted inputs. Associative learning approaches seek to match current data with stored patterns.
[0149] The subject cognitive system emphasizes connectionist classifiers as these methods require the fewest assumptions and are most applicable to problem in which a priori information is lacking. FIG. 2( d ) shows an example of signal classification based on the extracted features from FIG. 2( b ). The compared features are spectral bandwidth (BW), temporal width of the clusters (TW), and center frequency for each of the clusters (FC) for the received over the air collected data for the signals belonging to the Bluetooth™ as is disclosed in IEEE Standard for Wireless Personal Area Networks Based on the Bluetooth™ v 1.1 Foundation Specifications. http://www.ieee 802. org/ 15/ pub/TGI.html , IEEE Std. 802.15.1, 2002, the contents of which are incorporated herein by reference; and also IEEE 802.11b and IEEE 802.11g Standards. For the processed signals, these three features effectively characterize signals as belonging to one of the three classes. The clusters are generated using the Single Linkage Clustering Algorithm. A nearest-neighbor classifier is then used to match each input signal feature triplet (BW, TW, FC) to the existing cluster centroids.
[0150] It is noted that open set classification helps to detect a new signal. Open set classification is the classification of data from signal classes that were not part of the original training set (the closed set). Classifiers that are not designed to account for this eventuality will often attempt to assign the received signal to one of the training set classes, potentially resulting in a misclassification. Real and Baumann have proposed a method for overcoming this problem based on the tolerance interval analysis as is disclosed in E. C. Real and A. H. Baumann, “Open set classification using tolerance intervals,” Thirty - Fourth Asilomar Conference on Signals, Systems and Computers , Volume 2, Page(s):1217-1221, Oct. 29-Nov. 2, 2000, the contents of which are incorporated herein by reference.
[0151] Open set classification plays an important role in a cognitive communications system to detect and classify a new signal. Another way of thinking about the open set classification is as follows. A given set of training data will cover some volume of the class's actual (unknown) feature space. If one would like the training data to cover c % of the actual class feature space with probability P, we can compute the number of independent training samples N required. From the training data one computes closed bounds specifying the set membership volume of a given class, as opposed to partitioning the entire feature space into a finite number of regions. When a new feature vector falls outside all of the established regions, it is declared as a new class. Open set classification is an important functionality of a cognitive communications system.
[0152] 4. Machine Learning and Prediction
[0153] Machine Learning can be concisely defined as a process when a machine (e.g. a computer program) changes its structure, program, or data in response to inputs so that its future performance improves as is disclosed in P. Nilsson, Introduction to Machine Learning, http://ai.stanford.edu/people/nilsson/mlbook.html, 1996, the contents of which are incorporated herein by reference. While many software programs are designed to perform the same way each time they are run, it is often useful to develop programs, algorithms, and systems that can learn from experience. The subject cognitive communications system is based on the concept that the deployed system will learn from its RF environment by characterizing new types of signals and transmission protocols, using an incremental learning approach that continues to adapt while the system is operational and new data is collected.
[0154] A system that can learn will mimic aspects of pattern matching and prediction as performed in human cognition. The pattern-matching function of our brain is constantly producing short-term predictions based on stored patterns and incoming sensory data; most of the time these predictions are correct. Failed predictions, however, lead to learning, which is the development of new patterns. This cognitive pattern matching and prediction model can be profitably applied to problems in which the range of potential patterns and features of interest are limited. A cognitive communications system is a good example of such a problem, since the features of interest are limited to time and spectral features of signals, with no need for external data or decoding of the information contained in the signals themselves. The subject system further limits the scope of the problem by developing a pattern-matching and prediction algorithm implemented on conventional (Von-Neumann architecture) computers.
[0155] As shown in FIG. 2( c ), machine learning enables a self-designing, self-adapting classifier, in contrast to standard classifier design which is heavily reliant on (human) designer inputs, since the types of objects to be classified are often problem-specific, and can change over time. In particular, machine learning enables our system to:
Characterize the time and frequency domain behavior of the signal types Predict the future time and frequency domain behaviors of the signal types Identify the presence of new signal types Construct models and features for new signal types Maintain previously acquired knowledge (old signal types) Modify weightings based on observed data
[0162] The subject approach develops predictions of future values of specified features using multiple adaptive learning predictor functions. It matches the input feature values to stored measurements of previously observed patterns and develops a prediction from each pattern based on current feature values and accumulated prior history. The best prediction at each time frame is selected based on the calculated confidence of each predictor for its current input values.
[0163] The first step is to develop clusters of patterns. The clustering is based on the similarity of key features for these patterns, and can be performed using a clustering algorithm such as Single Linkage Algorithm. Each cluster then represents a type of pattern. For each cluster, predictions of future feature values can be developed using one or more of the features used to characterize the cluster. The input and output values for each predictor are based on the observed statistics to date for that cluster. The statistics (# of outputs of parameter value Z in terms of input parameter values X, Y, etc) for each cluster are stored rather than the series of raw inputs.
[0164] In operation, each input data set of features is compared to the existing clusters to determine what type of pattern is being matched. The comparison can be made using classification algorithms such as Nearest Neighbor Algorithm. In order to select the best prediction at each point in time, the quality or confidence value of each predictor is calculated. The quality measurement used is the measure of the ambiguity of each specific output prediction, with the least ambiguous prediction being the best. This can be measured, for instance, by calculating the fullwidth at half maximum for each predictor (based on the input values) and selecting the narrowest one. The ambiguity or quality measurement can be used to place error bars around the predicted time of next transmission. If none of the predictors provide a high enough confidence value for satisfactory end-system use, additional predictors can be developed for future use by adding more input features (either internal to the signal or external, such as time of day) or developing predictors for higher-level (multi-layer) patterns.
[0165] FIGS. 3( a )- 3 ( d ) show the machine learning and prediction module that will estimate the future behavior of the signals. This setoff figures show how incremental learning improves the performance of the next time hop predictor for the Bluetooth™ signal shown in 3 ( a ). As more information is available, the prediction spikes become larger improving the prediction capability shown in 3 ( c ) and 3 ( d ). The FIG. 3( b ) shows how based upon certain quality factors the best predictor may be chosen from a library of predictors.
[0166] 5. Decision Metrics and Policies
[0167] In order for a number of cognitive communications devices to operate in the network, certain policy sets must be devised. These policy sets make the co-existence of multitudes of such devices possible. There may be policies for signal transmission, for the initialization protocols, for spectrum usage per node, etc. The devised policy sets must also keep in mind that not all the devices operating in the network will have cognitive capabilities.
[0168] The prior art has started looking into the game-theoretic approaches to choosing the right set of policies as is disclosed in S. Haykin, “Cognitive Radio: Brain-Empowered Wireless Communications,” IEEE J. Select. Areas Commun ., vol. 23, no. 2, pp. 201-220, February 2005, the contents of which are incorporated herein by reference. Amongst the many techniques, no-regret algorithms hold promise. No-regret algorithms are probabilistic learning algorithms which specify that players explore the space of actions by playing all actions with some non-zero probability, and exploit successful actions, by increasing the probability of employing those actions that generate high profits. Learning converges to the correlated Nash equilibrium. No regret algorithms try to minimize regret or leave no-regret externally or internally as follows:
External Regret: Difference between the payoffs achieved by the strategies prescribed by the given algorithm, and the payoffs achieved by any other fixed sequence of decisions, in the worst case. Internal Regret: Difference between the payoffs achieved by the strategies prescribed by the given algorithm, and the payoffs that could be achieved by a re-mapped sequence of strategies.
[0171] The LaGrangian hedging algorithm chooses an optimal policy from a very large set of policies by LaGrangian multipliers. It involves two steps, I. Prediction and II. Scaling. Prediction tries to estimate the cost of choosing a wrong policy and scaling weighs the risk and the cost. LaGrangian multipliers are used to not let the regret vector to grow. A hedging parameter must be chosen which tries to evade the risk of defeat by keeping the option of retreat open.
[0172] In a Φ-No-Regret algorithm, the set of policies to choose from is smaller. A weighting function maximizes the utility function resulting in a guaranteed convergence to some Φ equilibrium. This algorithm has a potential for using mixed strategies.
[0173] 6. Cognitive Communication in White as Well as the Gray Space
[0174] The goal of this program has been to develop a cognitive capability to detect and classify the signal types present in a given spectrum of interest without going into the signal internals, to learn the time and frequency domain patterns of the received signals, predict their future behavior and based on certain policy sets to transmit a signal in the White as well as the Gray space such that the new signal or signals do not interfere with the existing ones. As described above, the subject system uses two different policy sets. One, for a non-competitive cognitive device that will use only as much space for signal transmission as it requires, and the other for a competitive cognitive device that will use the prediction information to occupy all the possible space that it thinks is available.
[0175] FIGS. 4( a )- 4 ( e ) show this non-interfering signal transmission in the White as well as the Gray space based on our policy sets. FIG. 4( a ) shows a scenario where the classifier detects a (Single-Carrier+Non-Frequency Hopping+Broad-band=DSSS signal). Based on the policy set, a Frequency Hopping Spread Spectrum (FHSS) waveform is transmitted over the entire band. FIG. 4( b ) shows a scenario where the classifier detects a (Multi-Carrier+Non-Frequency Hopping+Broad-band=Orthogonal Frequency Division Multiplexing (OFDM) signal). An FHSS signal is transmitted only in the White Space. FIG. 4( c ) shows an example of a non-competitive communication scenario which makes use of only as much band-width as it needs making sure that the original FHSS (Multi-Carrier+Frequency-Hopping+Narrow-band) signal is not destroyed. FIG. 4( d ) shows an example of a competitive signal transmission where prediction information in time as well as the frequency is used to transmit in all the possible windows that the radio “thinks” are available. Error in prediction results in a part of the original signal being destroyed. This example showed a simple scenario for signal transmission in the White as well as the Gray spaces using non-competitive and competitive policy sets.
[0176] FIG. 4( e ) shows the general flow diagram for a non-interfering and jam-resistant cognitive communications system where the functionalities shown in FIGS. 1( a ) and 1 ( b ) have been incorporated along with the Physical (PHY) layer policy sets. The system initially performs spectrum sensing/signal detection. If no signal is detected then this is termed as a White Space, else it is termed as a Gray space. For a Gray space, feature extraction, signal classification and machine learning are used to match a signal and/or the communications protocols to a known type/Standard etc. Based on the decision made by the machine learning and prediction module, action is taken based upon competitive or co-operative policy sets shown in the Scenario and Action Table in FIG. 4 ( f ).
[0177] 7. Cognitive Jamming
[0178] FIG. 5( a ) shows the general flow diagram for a cognitive jamming system where the functionalities shown in FIGS. 1( a ) and 1 ( b ) have been incorporated along with the Physical (PHY) layer policy sets. The system initially performs spectrum sensing/signal detection. If no signal is detected then this is termed as a White Space and no action is necessary. Otherwise it is termed as a Gray space. For a Gray space, feature extraction, signal classification and machine learning are used to match a signal and/or the communications protocols to a known type/Standard etc. Based on the decision made by the machine learning and prediction module, action is taken to jam the existing signal in the most energy efficient manner. The Scenario and Action Table for cognitive jamming PHY layer policy sets are shown in FIG. 5( b ).
[0179] In summary, the present invention involves a cognitive communications system that combine the areas of communications, signal processing, pattern classification and machine learning to detect the signals in the given spectrum of interests, extracts their features, classifies the signals in types, learns the salient characteristics and patterns of the signal and predicts their future behaviors. Sophisticated signal processing enables extraction of the salient features of the signal without going into their internals. Incremental learning allows knowledge enhancement and improved prediction capability with time. The cognitive communications system uses the classification and prediction information to transmit a signal in White as well as the Gray space such that it does not interfere with the existing users, resulting in increased and efficient usage of the spectrum. Two policy frame-works are devised for non-competitive and competitive cognitive devices. A non-competitive device plays it safe and uses only as much space that it needed. On the other hand a competitive or a greedy device uses all the space that it thought it could have based on the prediction information resulting in errors and interference with the existing users in the spectrum.
[0180] While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications or additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims. | In a method of cognitive communication a system for generating non-interfering transmission, includes conducting radio scene analysis to find grey space using external signal parameters for incoming signal analysis without having to decode incoming signals. | 8 |
BACKGROUND OF THE INVENTION
Weighing scales including a platform upon which an individual may stand and a base for housing structure both to support and translate movement of the platform relative to the base to movement of a graduated scale to be read are known. It is also known that the weighing scales may include an optical system whereby light from a source is passed through the graduated scale so that the image of indicium from the graduated scale is reflected by one or more mirrors to a projection screen carried by the platform. The image on the screen is representative of the weight of the individual. A form of the prior art weighing scales of this type may be seen in Grusin et al. U.S. Reissue Pat. No. 28,040, dated June 11, 1974.
While this form of prior art weighing scales overcomes what has been considered to be one of the principal objections to the weighing scales without the foregoing optical system, namely, the difficulty in read-out of weight, either because of the size or legibility of the indicia or inadequate lighting of the indicia, the prior art has the disadvantage that frequently inaccuracy is introduced to the read-out of weight because of deformation of the base structure upon which the source of light and the graduated scale are independently supported relative to the base. This problem becomes more prevalent through the mass production of weighing scales required to meet commercial demands and, although the deformation may be small, the magnification of the indicia of weight by the optical system can lead to non-negligeable errors in the read-out at the projection screen.
BRIEF DESCRIPTION OF THE INVENTION
The present invention seeks to overcome the above disadvantage in the prior art and the weighing scales according to the invention is distinguished therefrom by the fact that it comprises a support plate upon which both the light source is fixed and the graduated scale is pivotally mounted for movement, as will be described. The support plate is fixed to the base at a plurality of points included within a plane which is at least substantially parallel to and in closely spaced proximity to the optical axis of the beam of light for the light source serving to project the indicia of the graduated scale toward a projection screen. Further, the plane and the optical axis are coincident at the pivotal axis of the graduated scale.
By this construction, it is possible substantially to eliminate error resulting from the deformation in the base which otherwise may cause a relative angular displacement of the graduated scale and the light source about the axis of the graduated scale. Possible deformation in the base transmitted to the support plate is overcome by relocating both the optical axis and the axis of the graduated scale without relocation of their relative disposition, one to the other. Thus, precision in read-out is not lost.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of the scales of the present invention, the platform first having been removed for purposes of illustration of the structure thereunder;
FIG. 2 is an enlarged vertical section as seen along the line 2--2 in FIG. 1, the platform having been repositioned over the base; and
FIG. 3 is a view similar to FIG. 2 as seen along the line 3--3 in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The scales of the present invention is of the type commonly referred to as a bathroom scales and provides mechanical system components which respond to the weight of an individual on a movable platform for movement of a graduated scale and optical system components which function to project an indicium representative of the weight of an individual on a projection screen carried by the platform.
The scales comprises a base 6 and a platform 1. Both the base and platform are formed of a material which displays structural characteristics, among others, of strength, durability, and rigidity thereby to permit the scales to withstand and respond to the weight of an individual on the platform, as described. The material, also, should display aesthetic characteristics, such as luster. While the base and platform preferably are formed of one of the commonly employed synthetic plastic materials they likewise may be formed of metal or other material capable of being molded or otherwise formed to the outline as may be seen in the Figures. Thus, the base and platform both may be round in plan view. The platform, further, provides an upper contoured surface and a depending skirt integral therewith; whereas, the base provides a lower surface which surrounds a central area and which connects the central area with an upstanding wall also integral therewith and concentric with the skirt. The upstanding wall and lower surface of the base together with the skirt and upper surface of the platform define the housing of the scales.
The inner surface of both the base and the platform are suitably ribbed to increase strength characteristics of the plastic.
The central area of the base is recessed somewhat within the housing. The central area is irregularly formed for purposes of mounting various components of the mechanical and optical systems, to be described below. A cover plate 6' is received by the base in the plane of the lower surface to complete the housing enclosure. The cover plate may include a plurality of supporting feet (not shown) and provides a plurality of access openings for purposes as will become clear.
The skirt of platform 1 is provided with an outer annular cutout whose length measured from the rim of the skirt determines substantially the limit of axial movement of the platform relative to the base.
A lustrous coating layer may be adhered or otherwise applied to the platform 1, as illustrated in FIG. 1, for enhancement of appearance of the scales. The base 6 may be formed of the same material as the coating layer.
The structure for mounting the platform 1 on base 6 and the mechanical components for translating axial movement of the platform relative to the base to rotary movement of a graduated scale may be seen to best advantage in FIGS. 1 and 3.
Referring now to FIGS. 1 and 3, the central ribbed area of the base 6 is formed to provide a plurality of projections or pedestals 5 which extend upwardly toward the platform 1. The pedestals extend perpendicular to the plane of the platform and, preferably, are arranged in a rectangular array with each pair of alternate pedestals located on a diagonal whose intersection with the diagonal between the other pair of pedestals is within the plane including the optical axis and the fixed axis 12 of the graduated scale carried on sector-shaped member 11. The point of intersection is slightly removed from the fixed axis 12 toward a light source 15.
Each pedestal 5 carries an element 5' which, in turn, supports a knife edge member 4. A like plurality of projections or pedestals 5a are supported by rib structure 1' on the underside of platform 1 and extend downwardly toward the base 6. These pedestals 5a, similarly extend perpendicular to the plane of the platform and are disposed in an array to cooperate with each pedestal 5. Each pedestal 5a likewise carries an element 5a' which supports a knife edge member 2. The two pairs of knife edge members 2, 4 on opposite sides of fixed axis 12 are disposed along parallel chords which are laterally spaced apart. For stability of the platform 1 on the base 6 the plane of the chord including the knife edges 4 are disposed substantially equidistantly from the point of intersection of the diagonals from the pairs of alternate pedestals 5.
A pair of bars 3 of relatively flat upper and lower contour and of a length at least to span the space between cooperating pedestals serve to support the platform 1 on the base 6. To this end, each bar provides adjacent its ends and offset across the width an upper and lower V-shaped recess 2' and 4' for receipt therein of the knife edges 2 and 4, respectively. Each bar carries at least one lever arm which extends toward the base 6. To this end, the bar to the left of the fixed axis (direction taken from FIG. 1) supports a pair of lever arms 7 located between and substantially equidistantly spaced from one pair of pedestals 5, while the bar to the right of the fixed axis supports a single lever arm 8 which is substantially equidistantly spaced between the other pair of pedestals 5. Each lever arm provides a V-shaped notch adjacent the end away from the bar, each notch being concave toward the right, as seen in FIG. 3. Each lever arm is fixedly carried by its respective bar to move with the bar.
The bars 3 and lever arms 7, 8 form a part of a conventional multiplying mechanism which translates a change in axial displacement of the platform 1 relative to the base 6 in response to the weight of an individual on the platform to a displacement of a slide 9 located below the platform horizontally to the right in FIG. 3. Displacement of the slide is in opposition to the bias of spring 20 from a position of rest.
Slide 9 is formed by a generally flat, elongated rectangular plate. The plate includes a cutout for receipt of the lever arm 8 and a pair of notches into which the lever arms 7 are received. Each of the notches and cutout in the plate provide a knife edge (not shown) for cooperation in the V-shaped notch formed in the respective lever arms 7, 8. When the platform 1 is subjected to the weight of an individual and translates downwardly, the bars 3 pivot counterclockwise about the knife edge members 4 thereby through cooperation of the lever arms 7, 8 and slide 9 to cause the slide to displace horizontally, as described. When the platform no longer is subjected to the weight the tension of spring 20 draws the slide toward the position of rest. Simultaneously, lever arms 7, 8 and bars 3 pivot clockwise about the knife edge members 4. The result is that the platform 1 moves upward.
A pair of arm elements 7', 8', also may be carried by the bars 3 and depend toward the slide 9. The arm elements cooperate in the notches 7", 8" of slide 9, respectively, and each arm element includes a foot portion for receipt under the surface of the plate. The arm elements act both to provide stabilization of the bars 3 and slide 9 and to support the slide above the surface of a channel formed along the central area of the base 6.
The mechanical system includes, further, the sector-shaped member 11 which is mounted for pivotal movement about the fixed axis 12. The sector-shaped member 11 includes a pair of arms which diverge generally radially outwardly from their junction, the arms being connected at the other end by an arcuate segment having a length of less than 90°. A stub shaft extends downwardly of the sector-shaped member 11 substantially at the junction of the intersection of its arms. A smaller sector-shaped member 11" is disposed below the sector-shaped member 11 and supported by the stub shaft and arms. The sector-shaped member 11" provides a projection 14 whose axis substantially is parallel to the axis of the stub shaft.
The graduated scale is carried on a transparency 11', in the form of a film forming portion on a cylinder. The transparency may be removably supported on the arcuate segment of sector-shaped member 11 by any convenient means in position so that the graduations of the scale may move through the optical axis.
The transparency carries graduations representative of the weight of an individual in a convenient scale, throughout an arcuate length of about 45°. The transparency, further, is mounted independent of the mounting of the sector-shaped member 11. A typical manner of mounting may be to secure the transparency between a spring (not shown) and a flat face of the arcuate segment. The spring, in turn, may be connected between a pair of spaced projections (not shown) extending from the flat face.
The plate 21 is mounted by the rib structure within the central area of the base 6. The plate resides above the slide 9 and includes a cutout 21' above the region of the channel along which the slide 9 moves. The plate also includes a circular aperture defining the fixed axis 12. The stub shaft is received in the aperture to provide a pivot for the sector-shaped member 11.
An abutment member 10' is fixedly carried by the slide 9. The abutment member 10' is spaced from an upstanding edge along substantially the length of the slide by a distance to provide a channel for movement of an element carrying a pin 10. The pin extends from the element toward the platform 1 and includes a projection substantially normal thereto. The element is retained in the channel formed by the abutment member and through action of spring 13, the projection on pin 10 is biased into engagement with projecton 14 on the sector-shaped member 11". The spring is secured between the element and an ear struck from the slide 9. Thus, as the slide 9 translates to the right under the weight of an individual on platform 1 the projection on pin 10, in engagement with the projection 14, pivots the sector-shaped member 11 about the fixed axis 12. The spring 13 assures engagement of the projections over a full path of movement of the sector-shaped member to obviate substantially any lost motion which shall introduce error.
The abutment member 10' provides a pin (not shown) which engages with the opposite side of the projection 14. In this manner when the individual shall have stepped from the platform 1, the sector-shaped member 11 will pivot in the opposite direction under the influence of spring 20 as slide 9 returns to the position of rest.
A housing 25 enclosing the light source 15 and a pair of lenses 15' is supported by the plate 21. Preferably, the light source is disposed at a position radially outwardly of the transparency 11' to increase the length of the optical path. As illustrated in FIG. 1, the lenses 15' are located on opposite sides of the transparency 11'. The first of the lenses causes the beam of light from source 15 to travel in a parallel path toward the transparency while the second of the lenses thereafter directs the illuminated image of indicium to a mirror 16. The mirror 16 is disposed on the opposite side of fixed axis 12 and comprises the first of a pair of mirrors for reflecting the illuminated image on a projection screen 18. To this end, the mirror 16 is disposed vertically and at an angle other than 90° to the optical axis which is generally along the section line 2--2 in FIG. 1. The illuminated image of the indicium is reflected to a second mirror 17 located at an angle of approximately 45° measured from the plane of the projection screen 18. While the light source 15 and the fixed axis 12 are supported by plate 21 to reside at constant spacing, and the optical axis intersects the fixed axis, the mirrors 16 and 17 are fixed to a support carried by base 6. The fixed relationship of the fixed axis 12 and light source 15 improves the quality of transmission of the image of indicium and facilitates measuring.
The projection screen 18 is supported on a shoulder formed in the platform 1 and secured in position by the coating layer which is received thereover. To this end, the projection screen may include an upper translucent window surface and an annular offset base surface. The base surface is supported by the shoulder and the upper surface is received through an opening in the coating layer to be flush with the contour.
The light source, for example, may be formed by an electric lamp A power source in the form of a battery including a plurality of individual cells 24 is carried in the housing 25 for supplying current to the electric lamp. As indicated, the cover 6' includes a plurality of access openings, one of which permits replacement of the batteries, the other of which permits replacement of the electric lamp, as necessary. The cells 24 are arranged in series by suitable electrical connection within the housing and on a door (not shown) mounted by cover 6' to close the access opening. A plurality of conductive straps 25' electrically connect the cells to the electric lamp.
The projection path may be seen in FIG. 2, and as indicated this path coincides with section line 2--2 between the electric lamp and mirror 16. The image of indicium projected and reflected to the projection screen 18 is magnified many times. The magnified image of indicium may be read in relation to an index (not shown) disposed at the edge of the projection screen 18. The magnification factor (which may be in excess, for example, of eighteen times) permits that the scale graduations on the transparency be relatively small in size and extend only within the aforementioned arcuate length for full scale reading. A significant advantage is greater precision of operation. And, as a further advantage of the samll angular displacement of scale graduation for full scale reading, it is possible to drive the sector-shaped member 11 by the projection on pin 10 acting upon the projection 14. This is a rather uncomplex and rather inexpensive drive when considering the conventional rack and pinion drive of the prior art.
The housing 15, mounted on plate 21, is capable of undergoing slight adjustment along the optical axis for positioning of the lenses 15' relative to the transparency 11'. This will enable focusing of the indicium on the projection screen. To this end, the lenses are fixed to the housing. The light source, mounted by a plug 15" received by plate 21, as described, is fixed relative to the fixed axis 12. The housing includes an opening toward the fixed axis 12 and a slot through which the transparency moves.
As noted in FIG. 2 the plug 15" is received through to close the other access opening in cover plate 6', and supported by plate 21 in conventional manner.
The plate 21 is fixed to base 6 by a plurality of screws 22, 23, one of which is disposed on one side of the optical axis and the other of which is disposed on the other side of the optical axis. Both screws are spaced a small distance normal to the optical axis so that a straight line between the mounting screws relative to the optical axis is substantially parallel to the optical axis and intersects the optical axis at the fixed axis 12 of sector-shaped member 11. The manner of mounting of the plate 21 has the effect of turning the optical axis and the transparency 11' about the optical axis of the transparency and the light source about the axis 12. The mounting thereby will eliminate any error resulting from an angular displacement produced by deformation in the base 6.
A switch 26' including a pair of relatively movable contact arms 26a, 26b is connected to the conductive straps 25' from the cells. The contact arms normally are biased apart to maintain the circuit including the light source and cells open. The switch is operable automatically when an individual stands on the platform 1 and may be operated at other times for purposes of zero setting of the scales. To these ends, the contact arm 26a is controlled by an ear on slide 9 and movable toward the contact arm 26b as the slide 9 is actuated to the right. For zero setting of the scales, a contact arm portion 26c struck from contact arm 26b is movable toward contact arm 26a, again to close the circuit to the light source. Movement of the contact arm 26c is controlled by an elongated member 26 having a button at one end and a tab at the other end. The elongated member is movable back and forth along a prescribed longitudinal path and biased toward the upstanding wall of the base 6 by engagement of the tab and contact arm 26c. The button is readily accessible and movable within an aperture in the wall in the other direction. When the transparency is illuminated the tension on spring 20, as conventional, may be adjusted thereby to cause sector-shaped member 11 to pivot about the fixed axis 12 through engagement of the projection on pin 10 and projection 14. As apparent, rotation of adjustment button 19 is continued until the numeral "0" is located at the index of projection screen 18.
Having described the invention with particular reference to the preferred form thereof, it will be obvious to those skilled in the art to which the invention pertains after understanding the invention, that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the claims appended hereto. | A weighing scales has a base and a platform supported by the base and adapted to support an individual. A transmission mechanism within the base is responsive to movement of the platform for causing pivotal translation of a graduated transparency. A beam of light from a light source is projected along an optical path through the transparency and reflected to a projection screen carried by the platform for read-out of weight. The light source is carried on a support plate which is mounted to the base by means disposed at two points on a line at least substantially parallel to the optical axis and coincident with the optical axis substantially at a fixed axis of the graduated transparency. The transparency is pivotally mounted on the support plate and presents a convex face toward the light source. | 6 |
This application is a continuation of application Ser. No. 481,322, filed 3/31/83.
FIELD OF THE INVENTION
The present invention relates to a novel polyglycerol compound useful as a nonionic surface active agent or surfactant and a cosmetic product containing it.
BACKGROUND OF THE INVENTION
The nonionic surfactants known in the art and used widely include glycerol fatty acid esters, sorbitan fatty acid esters, poly(oxyethylene)sorbitan fatty acid esters, poly(oxyethylene) fatty acid esters, poly(oxyethylene)alkyl ethers, poly(oxyethylene)alkyl phenyl ethers, hydrogenated castor oil poly(oxyethylene) adducts and the like. These surfactants are generally broken down into lipophilic and hydrophilic types, the former having no poly(oxyethylene) chain or a short poly(oxyethylene) chain and the latter having a long poly(oxyethylene) chain. A surfactant mixture containing a higher proportion of hydrophilic surfactants provides a oil-in-water (O/W) type emulsion having its hydrophilic-lipophilic balance (HLB) adjusted to 10-15, while a surfactant mixture containing a higher proportion of hydrophilic surfactants provides a water-in-oil (W/O) type emulsion having its HLB adjusted to 4-6. Thus sophisticated adjustment of the hydrophilic-lipophilic balance is required for the preparation of stable emulsions. With the nonionic surface active agents, that adjustment is performed making use of the poly(oxyethylene) chain. This is because the control of the chain length of ethylene oxide is easy and can meet sufficiently the requirement on sophisticated HLB. However, the surfactants to which ethylene oxide is added have some disadvantages in that dioxane forms during synthesis, they suffer oxidation with the lapse of time so that elution of formaldehyde takes place and their pH shifts toward acidity. These problems may be solved by the addition of antioxidants; however, the use of such antioxidants is unpreferable in view of safety.
On the other hand, the nonionic surfactants known in the art and used extensively as solubilizers include poly(oxyethylene)octyl phenyl ether, poly(oxyethylene)nonyl phenyl ether, poly(oxyethylene)oleyl ether, poly(oxyethylene)monolaurate, poly(oxyethylene)monooleate, hydrogenated castor oil poly(oxyethylene) adducts, poly(oxypropylene)poly(oxyethylene)cetyl ether, poly(oxyethylene)2-hexyldecyl ether and the like. All of these solubilizers are Micelle-dissolved in water, and are so adjusted that the resulting aqueous solutions are put into a relatively hydrophilic state having a HLB of not less than 12 so as to solubilize oily matters, perfumes, oil-soluble matters, etc. To this end, ethylene oxide is unexceptionally added to the solubilizers. Like the foregoing emsulsifiers, however, the aqueous solution of surfactants to which ethylene oxide is added causes elution of formaldehyde and its pH shifts toward acidity, since the chain of ethylene oxide undergoes oxidation with the lapse of time. To this end, antioxidants or buffer solutions are added for pH adjustment. However, there is an increasing demand for solubilizers substantially in sensitive to oxidation in view of both safety and the stability of products. To add to this, the conventional solubilizers generally have so long a defoaming time that, when they are applied over the inside of a container or the skin, there are still some bubbles remaining on the surface thereof, which pose problems in connection with appearance and touch.
The aforesaid emulsifiers and solubilizers share a common problem. Antiseptics now used with cosmetic include paraben compounds such as methylparaben, which are known to be adsorbed onto the ethylene oxide moieties of surfactants and hence less effective.
U.S. Pat. No. 3,846,546, West German Pat. No. 1 719 434 and French Pat. No. 1 553 145 specifications disclose emulsifiers that are related to compounds of the present invention. However, since these known emulsifiers are of the branched structure that 1, 2 bonding is present in the alkylene oxide group, the following disadvantages are found from the standpoint of synthesis; (1) an alcohol used as a starting material remains unreacted, (2) the distribution of molecular weight is wide, (3) an addition reaction does not proceed so that difficulties are encountered in making them hydrophilic, (4) the content of polyglycerol unbonded to the starting alcohol is high, etc. In view of their physical properties, the known emulsifiers are also disadvantageous in that they are poor in solubility in water and dispersibility in O/W emulsions so that they do not function as good solubilizers and emulsifiers for O/W emulsions. This holds for even the compounds of these emulsifiers having an increased number of moles of hydrophilic groups present.
SUMMARY OF THE INVENTION
As a consequence of intensive studies made to eliminate the defects of the prior art, a novel nonionic surface active agent has been found, which is very easy to synthesize, excels in emulsifiability and solubility because of the straight-chain carbon skeletons of the polymethylene oxide groups, undergoes substantially neither elution of formaldehyde nor pH changes, has an improved resistance to oxidation, a reduced defoaming time in a soluble system and no stimulating effect on the skin, and is safe and stable. The present invention is also concerned with a cosmetic product in which the novel surfactant is applied as an emulsifier or solubilizer.
A main object of the present invention is therefore to provide a novel nonionic surfactant, polyglycerol compound having the following general formula (I) or (II):
R.sub.1 O(X.sub.1)m.sub.1 --Y.sub.1 --.sub.n.sbsb.1 H (I)
wherein R 1 is a straight-chain or branched, saturated or unsaturated aliphatic alcohol residue having carbon atoms of 8-36, X 1 is CH 2 CH 2 CH 2 O and/or CH 2 CH 2 CH 2 CH 2 O, Y 1 is a glycerol group, m 1 equals 3-60, and n 1 equals 4-60, or
R.sub.2 COO(X.sub.2)m.sub.2 --Y.sub.2 --.sub.n.sbsb.2 H (II)
wherein R 2 is a straight-chain or branched, saturated or unsaturated fatty acid residue having carbon atoms of 7-35, X 2 is CH 2 CH 2 CH 2 O and/or CH 2 CH 2 CH 2 CH 2 O, Y 2 is a glycerol group, m 2 equals 3-60, and n 2 equals 4-60.
Another object of the present invention is to provide a hydrophilic cosmetic product (O/W, solublized, water-dispersed) containing at least one or two or more of the polyglycerol compounds expressed by the general formula (I) or (II):
R.sub.1 O(X.sub.1)m.sub.1 --Y.sub.1 --.sub.n.sbsb.1 H (I)
wherein R 1 is a straight-chain or branched, saturated or unsaturated aliphatic alcohol residue having carbon atoms of 8-36, X 1 is CH 2 CH 2 CH 2 O and/or CH 2 CH 2 CH 2 CH 2 O, Y 1 is glycerol group, m 1 equals 3-60, and n 1 equals 4-60, or
R.sub.2 COO(X.sub.2)m.sub.2 --Y.sub.2 --.sub.n.sbsb.2 H (II)
wherein R 2 is a straight-chain or branched, saturated or unsaturated fatty acid residue having carbon atoms of 7-35, X 2 is CH 2 CH 2 CH 2 O and/or CH 2 CH 2 CH 2 CH 2 O, Y 2 is a glycerol group, m 2 equals 3-60, and n 2 equals 4-60.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other objects and features of the present invention will become apparent from the following detailed description with reference to the accompanying drawings, in which:
FIGS. 1, 2 and 3 are NMR charts of the compound after acetylation of poly(glycerol)(10)poly(1,4-oxybutylene)(9)2-octyldodecyl ether, poly(glycerol)(16)poly(1,4-oxybutylene)(12)stearyl ether and poly(glycerol)(32)poly(1,4-oxybutylene)(32)oleyl ether;
FIGS. 4 and 5 are graphical views showing the results of testing on the amount of elution of formaldehyde and pH changes of an aqueous solution of nonionic surfactants, wherein
A is poly(glycerol)(10)poly(1,3-oxytrimethylene)(8)stearate,
B is poly(oxyethylene)(20)sorbitan monostearate,
C is poly(oxyethylene)(20)sorbitan monooleate, and
D is poly(glycerol)(16)poly(1,4-oxybutylene)(12)stearyl ether;
FIGS. 6 and 7 are graphical views showing the results of testing on the amount of elution of formaldehyde and pH changes of an aqueous solution of solubilizers, wherein
X is poly(glycerol)(16)poly(1,4-oxybutylene)(8)2-octyldodecyl ether, and
Y is hydrogenated castor oil poly(oxyethylene)(40) adduct; and
FIG. 8 is a graphical view showing changes on the volume of bubbles with the lapse of time observes on solubilized type lotion after shaking, wherein
(a) is poly(glycerol)(15)poly(1,4-oxybutylene)(14)2-octyldodecyl ether,
(b) is poly(oxyethylene)(30)2-hexyldecanoate
(c) is poly(oxyethylene)(20)oleyl ether, and
(d) is hydrogenated castor oil poly(oxyethylene)50) adduct
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made to the structure of the polyglycerol compounds according to the present invention. The inventive compounds expressed by both the formulae (I) and (II) are those of higher saturated.unsaturated alcohols having a straight or branched chain and carbon atoms 8-36 or higher saturated unsaturated fatty acids having a straight or branched chain and carbon atoms of 8-36 to which added are 7-120 moles of trimethylene oxide and/or tetrahydrofuran and glycidol in total, wherein polyglycerol compounds are at random polymerized with glycidol and trimethylene oxide and/or tetramethylene oxide. A Proportion of glycerol group and polymethylen oxido groups is 95:5-1:3.
In formula (I), m 1 and n 1 are in a range of 3-60 and 4-60, respectively, but preference is given to m 1 in a range of 4-30 and n 1 in a range of 5-30. When both m 1 and n 1 exceed 60 in formula (I), any desired surfactant having an emulsifying or solubilizing effect is not obtained since there is then a drop of nonionic surface activity. It is noted that the degree of surface activity attained in a range of above 30 to below 60 is relatively low. When R 1 in formula (I) is a straight-chain aliphatic aloohol, the resulting surfactant is preferably used as an emulsifier, and when R 1 is a branched aliphatic alcohol, the resulting surfactant is preferably used as a solubilizer.
In formula (II), m 2 and n 2 are in a range of 3-60 and 4-60, respectively, but preference is also given to m 2 of 4-30 and n 2 5-30. As explained with reference to formula (I), there is a lowering of surface activity, when both m 2 and n 2 exceed 60. As a result, any desired surfactant having the contemplated emulsifying and solubilizing effects is not obtained at all.
It is understood that m 1 /n 1 and m 2 /n 2 shall not exceed 3 in both formulae (I) and (II) from a viewpoint of surface activity.
The straight-chain or branched, higher saturated or unsaturated aliphatic alcohols used for the the polyglycerol ether type compounds expressed by formula (I) may include higher alcohols having carbon atoms 8-36 such as, for instance, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidic alcohol, behenyl alcohol, myricyl alcohol, oleyl alcohol, 5,7,7-trimethyl-2-(1',3',3'-trimethyl butyl)octanol, 2-ethylhexyl alcohol, 2-hexyldecyl alcohol, 2-heptylundecyl alcohol and 2-octyl dodecyl alcohol.
The straight-chain or branched, higher saturated or unsaturated fatty acids used for the polyglycerol ester type compounds expressed by formula (II) may include higher fatty acids having carbon atoms of 8-36 such as, for example, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, cerotic acid, melissic acid, 2-ethylhexanoic acid, 2-hexyldecanoic acid, 2-heptylundecanoic acid, 2-octyldodecanoic acid, 5,7,7-trimethyl-2-(1',3',3'-trimethyl butyl)octanoic acid and neodecanoic acid obtained by a reaction between an olefin and carbon monooxide. As the polymethylene oxide use may be made of trimethylene oxide, tetrahydrofuran, etc.
The polyglycerol ether type compounds expressed by formula (I) is synthesized as follows:
A mixture of glycidol with polymethylene oxide is gradually added for polymerization to the aforesaid alcohol or a solution thereof without a solvent or in a solvent such as chloroform or dichloromethane. The polymerization catalyst applied may be Lewis acids such as aluminium chloride, zinc chloride, zinc perchlorate and boron trifluoride-ether complexes. After the completion of reaction, the catalyst is removed with one or more of sodium hydrogen carbonate, sodium carbonate, potassium carbonate, basic alumina and the like. The solvent and unreacted matter are then distilled off under reduced pressure to obtain a viscous, oily or semi-solid product. Alternatively, only glycidol may be added dropwise to trimethylene oxide or tetrahydrofuran serving as a solvent.
The polyglycerol ester type compounds expressed by formula (II) may be synthesized in the manner as explained with reference to the synthesis of the polyglycerol ether type compounds of formula (I), provided that the aforesaid fatty acids are replaced for the alcohols. Another possibility is that a mixture of glycidol with polymethylene oxide is combined with the aforesaid Lewis acid being used as a catalyst, followed by removal of the catalyst and, thereafter, the resulting product is esterified in the conventional manner with or without an alkali catalyst into a viscous, oily or semi-solid product.
Increases or decreases in the content of polymethylene oxide are achieved by increasing or decreasing the amount thereof.
Typical examples of the higher aliphatic alcohol polymethylene oxide polyglycerol ether compounds and the higher fatty acid polymethylene oxide polyglycerol ester compounds of formulae (I) and (II) according to the present invention include:
poly(glycerol)(8)poly(1,4-oxybuthylene)(4)myristyl ether,
poly(glycerol)(14)poly(1,3-oxytrimethylene)(6)cetyl ether,
poly(glycerol)(20)poly(1,4-oxybutylene)(10)stearyl ether,
poly(glycerol)(10)poly(1,4-oxybutylene)(9)stearyl ether,
poly(glycerol)(20)poly(1,3-oxytrimethylene)(20)oleyl ether,
poly(glycerol)(32)poly(1,4-oxybutylene)(32)oleyl ether,
poly(glycerol)(15)poly(1,4-oxybutylene)(14)2-octyldodecyl ether,
poly(glycerol)(5)poly(1,3-oxytrimethylene)(6)palmitate,
poly(glycerol)(5)poly(1,4-oxybutylene)(10)stearate,
poly(glycerol)(6)poly(1,4-oxybutylene)(4)stearate,
poly(glycerol)(30)(1,3-oxytrimethylene)(20)oleate,
poly(glycerol)(20)poly(1,4-oxybutylene)(10)2-hexyldecanaote.
The present invention will now be elucidated with reference to the examples of synthesis of the inventive novel polyglycerol compounds.
SYNTHESIS EXAMPLE 1
Poly(glycerol)(10)poly(1,4-oxybutylene)(9)2-octyldodecyl ether
One (1) gram of a boron trifluoride ether complex was added to 28.5 grams of 2-octyldodecyl alcohol and 150 ml of tetrahydrofuran. 74 grams of glycidol were added dropwise for one hour agitation at 40° C. in a nitrogen stream. After the dropwise addition, the reaction was continued for further 30 minutes to completion. Thereafter, 20 grams of sodium bicarbonate were added to the reaction product which was treated under the same conditions for 4 hours. After filtration of insoluble matters, the solvent and unreacted glycidol were distilled off under reduced pressure to obtain the captioned compound as a colorless oil in a yield of 163 grams.
______________________________________ELEMENTAL ANALYSIS as C.sub.86 H.sub.174 O.sub.30 Carbon Hydrogen______________________________________Calcd. 61.21% 10.23%Found 61.18% 10.20%______________________________________
The NMR of the compound after acetylation is shown in FIG. 1.
SYNTHESIS EXAMPLE 2
Poly(glycerol)(16)poly(1,4-oxybutylene)(12)stearyl ether
One gram of zinc tetrachloride was added to 27 grams of stearyl alcohol and 140 ml of tetrahydrofuran. 119 grams of glycidol were added dropwise under agitation for one hour in a nitrogen stream. After the dropwise addition, the reaction was continued for further 30 minutes to completion. 30 grams of sodium carbonate were added to the reaction product which was then treated under the same conditions for 4 hours. After filtration of insoluble matters, the solvent and unreacted glycidol were distilled off under reduced pressure to obtain the captioned compound as a colorless semi-solid in a yield of 118 grams.
______________________________________ELEMENTAL ANALYSIS as C.sub.114 H.sub.130 O.sub.45 Carbon Hydrogen______________________________________Calcd. 56.55% 7.81%Found 56.59% 7.71%______________________________________
The NMR of the compound after acetylation is shown in FIG. 2.
SYNTHESIS EXAMPLE 3
Poly(glycerol)(32)poly(1,4-oxybutylene)(32)oleyl ether
One gram of a boron trifluoride ether complex was mixed with 27 grams of oleyl alcohol and 100 ml of dichloromethane. Which applying heat, a mixture of 240 grams of glycidol with 200 grams of tetramethylene oxide was added dropwise under agitation and reflux for about 4 hours in a nitrogen stream. After the completion of dropwise addition, the reaction was continued for further two hours. Thereafter, 20 grams of sodium carbonate were added to the reaction product which was then treated under the same conditions for three hours. After filtration of insoluble matters, the solvent and unreacted glycidol were distilled off under reduced pressure to obtain the captioned compound as a colorless semi-solid product in a yield of 450 grams.
______________________________________ELEMENTAL ANALYSIS as C.sub.210 H.sub.348 O.sub.97 Carbon Hydrogen______________________________________Calcd. 56.55% 7.81%Found 56.58% 7.79%______________________________________
The NMR of the compound after acetylation is shown in FIG. 3.
SYNTHESIS EXAMPLE 4
Poly(glycerol)(6)poly(1,3-oxytrimethylene)(4)2-heptylundecanoate
One gram of a boron trifluoride ether compolex was mixed with 28.4 grams of 2-heptylundecanoic acid and 100 ml of dichloromethane. A mixture of 45 grams of glycidol and 23.2 grams of trimethylene oxide was added dropwise to the obtained mixture for 4 hours under stirring and reflux in a nitrogen stream. After the addition, the reaction was continued for further two hours. Thereafter, 30 grams of potassium carbonate were added to the reaction product which was in turn treated under the same conditions for 4 hours. After filtration of insoluble matters, the solvent and unreacted glycidol were distilled off under reduced pressure to obtain the captioned compound as a colorless oil in a yield of 93 grams.
______________________________________ELEMENTAL ANALYSIS as C.sub.48 H.sub.98 O.sub.17 Carbon Hydrogen______________________________________Calcd. 60.89% 10.36%Found 60.77% 10.39%______________________________________
SYNTHESIS EXAMPLE 5
Poly(glycerol)(10)poly(1,3-oxytrimethylene)(8)stearate
One gram of a boron trifluoride ether complex was mixed with 9 grams of glycerol and 120 ml of dichloromethane. To the obtained mixture was added dropwise a mixture of 72 grams of glycidol and 47 grams of trimethylene oxide for 4 hours under agitation and reflux in a nitrogen stream. After the addition, the reaction was continued for further one hour. Thereafter, 20 grams of sodium bicarbonate were added to the reaction product which was then treated under the same conditions for 4 hours. After filtration of insoluble matters, the solvent and unreacted glycidol were distilled off under reduced pressure to obtain a mixture. 28 grams of stearic acid were added to the mixture at 230° C. for 4 hours. Removal of water gave the captioned compound as a colorless semisolid product in a yield of 114 grams.
______________________________________ELEMENTAL ANALYSIS as C.sub.72 H.sub.144 O.sub.30 Carbon Hydrogen______________________________________Calcd. 58.06% 9.68%Found 57.92% 9.70%______________________________________
The thus obtained poly(glycerol)poly(oxypolymethylene)alkyl ehters and the poly(glycerol)poly(oxypolymethylene) fatty acid esters that are novel polyglycerol compounds may be used alone or in combination and, optionally, with nonionic surfactants having no ethylene oxide chain such as sorbitan monostearate and glycerol monooleate having a HLB of not greater than 7, as an emulsifier.
The characteristic features of the emulsifer according to the present invention are that it has no ethylene oxide chain in its molecule and no 1,2-bonding in its polymethylene oxide groups. For this reason, the emulsifier undergoes little or no elution of formaldehyde and pH changes due to oxidation, so that considerable improvements are introduced in safety and stability. Because of its odorless, the inventive emulsifier helps reduce the chances of giving off an offensive smell. The inventive emulsifier also limits the adsorption of paraben compounds onto a surface active agent, and helps reduce the amount of antiseptics used.
To prove the feature of the inventive polyglycerol compounds according to which they can be used as emulsifiers, the following experiments were performed.
(1) Testing on Elution of Formaldehyde
Prepared were the novel emulsifying compounds according to the present invention [poly(glycerol)(10)poly(1,3-oxytrimethylene)(8)stearate and poly(glycerol)(16)poly(1,4-oxybutylene)(12)stearyl ether] and the known hydrophilic, nonionic surface active agents [poly(oxyethylene)sorbitan monooleate and poly(oxyethylene)sorbitan monostearate] in the form of 1% aqueous solutions. These solutions were allowed to stand for one month at 40° C. to determine the amount of formaldehyde by means of the acetyl acetone method. FIG. 4 shows the results, from which it is evident that the inventive products undergo little or no elution of formaldehyde even under a severe temperature condition of as high as 40° C.
(2) Testing on pH changes
Prepared were the novel polyglycerol compounds [poly(glycerol)(16)poly(1,4-oxybutylene)(12)stearyl ether and poly(glycerol)(10)poly(1,3-trimethylene)(8)stearate] and the known hydrophilic, nonionic surface active agents [poly(oxyethylene)(20)sorbitan monostearate and poly(oxyethylene)(20)sorbitan monooleate] in the form of 1% aqueous solutions. These solutions were allowed to stand for one month at 40° C. to determine changes in pH. FIG. 5 shows the results, from which it is evident that the inventive products are less than the known surfactants in the changes in pH.
These results are attributable to the fact that the novel compounds of the present invention have no 1,2-bonding in the polymethylene oxide groups. The surface active agents yet used in the art are prone to decomposition due to pH changes caused by the oxidation thereof. However, the inventive compounds do hardly show any sign of decomposition. Especially with a system wherein pharmaceutically active components are present such as various derivatives of ascrobic acid and glutathione, the decomposition of such active components is promoted according as the surfactant is oxidized. However, such a disadvantage is eliminated or reduced by the present invention.
Another aspect of the present invention will now be explained, according to which the inventive polyglycerol ether type compounds can be made more suitable for use in cosmetic emulsifiers.
Since the compounds of the present invention are available in the form of non-crystalline (semi-)solids, they can provide a creamy semi-solid emulsion which remains substantially intact in a low to high temperature region. As compared with this, the known emulsifiers such as poly(oxyethylene)(10)stearyl ether exhibit so high a crystallinity that there is a sharp change in hardness in the vicinity of their melting point of 40° C. It is thus likely that the emulsions may solidify at lower temperatures and flow at higher temperatures. Furthermore, the prior art poly(oxyethylene)sorbitan monostearate has so low a melting point that no cream having a sufficient hardness is obtained.
As explained above, the polyglycerol compounds of the present invention provide an ideal emulsifying system for cosmetics which shows a lower crystallinity as compared with the conventional polyethylene oxide, is highly stable to temperature and oxidation, and has its hardness varying to only a limited degree.
In general, cosmetics include antiseptics such as represented by paraben compounds for the purpose of preventing secondary contamination. Reportedly, the paraben compounds are less effective in an emulsifying system, since they are adsorbed onto the ethylene oxide chain of the surface active agent. With the inventive compounds, however, such deactivation is considered not to take place due to the absence of any ethylene oxide chain. To prove this, testing was carried out with emollient cream of Example 1 (O/W emulsion) containing as the emulsifier 5% by weight of poly(glycerol)(10)poly(1,4-oxybutylene)(9)stearyl ether of the present invention and 0.3% by weight of parabens (a mixture of methylparaben and butylparaben) and control emollient cream containing as the emulsifier the same amount of the prior art sorbitan monostearate and poly(oxyethylene)(20)sorbitan monostearate and the same amount of the parabens. In that testing, a difference in aseptic effect between both samples was determined with several mold and bacteria. The results are shown in Table 1.
TABLE 1__________________________________________________________________________Testing on Aspetic Effect Bacteria under testing Staphylococcus Aspergillus niger.sup.+ aureus.sup.+ Escherichia Penicillium Pscudomonas coli citrinum aerunginosaSamples under daystesting 0 1 2 4 7 0 1 2 4 7 0 1 2 5 7__________________________________________________________________________Ex. 1 (present ± - + + - - -invention)Control + + - -cream__________________________________________________________________________ Bacteria under testing Bacillus subtiles Candida albicans Aerobacter aerogenesSamples daystesting 0 1 2 5 7 0 1 2 5 7 0 1 2 5 7__________________________________________________________________________Ex. 1 - - - - - - - ± - -Control - - - + ± - - + ±cream__________________________________________________________________________ Number of Colonies - 0 ± 1-4 + 5-below 200 200-below 1000 1000-below 10.sup.4
From Table 1, it has been found that the emulsion system according to the present invention is superior in aseptic effect to the poly(oxyethylene)sorbitan base system. It has already been reported in The 34th Colloid and Interface Chemistry Symposium in Japan the intensity of fluorescence is increased upon the adsorption of parabens onto surfactants. Measurements were therefore made of the intensity of fluorescence 4 ppm methylparaben aqueous solutions in which dissolved were the same amount of the inventive polyglycerol base surface [poly(glycerol(15)poly(1,4-oxybutylene)(14)2-octyldodecyl ether] and the conventional polyethylene oxide base surfactant (Nikkol HCO-50, manufactured by Nikko Chemical K.K.) with the use of a fluorimeter type RF510 manufactured by Shimazu Seisakusho K.K. As a result, it has turned out that the intensity of fluorescence of the aqueous solution of the polyglycerol base surfactant is lower than that of the polyethylene oxide base surfactant. This means that the adsorption of parabens is so less that a smaller amount of antiseptics gives rise to the same effect.
Reference will now be made to the possibility of application of the inventive polyglycerol ether type compound to solubilizers. The poly(glycerol)poly(oxypolymethylene) branched fatty alcohol ehters expressed by formula (I) are Micelle-dissolved in water, and solubilize perfumes and oily matters. The characteristic feature of the solubilizers of the present invention is the absence of an ethylene oxide. Like the foregoing emulsifiers, therefore, the solubilizers causes little or no elution of formaldehyde and pH changes, and are colorless as well as odorless. The inventive solubilizer poly(glycerol)(16)poly(1,4-oxybutylene)(8)2-octydodecyl ether and the known solubilizer [hydrogenated castor oil poly(oxyethylene)(40) adduct] were prepared in the form of 1% aqueous solutions to determine the amount of elution of formaldehyde and pH changes in the same manner as described in connection with the aforesaid emulsifier. The results are set forth in FIGS. 6 and 7 and obviously indicate that the inventive solubilizer shows lesser signs of elution of formaldehyde and pH changes as compared with the known hydrogenated castor oil poly(oxyethylene) adduct that is said to be not noticeably varied among the nonionic surface active agents.
Still another feature of the present invention is that the compound of formula (I) may be used as a solubilizer for cosmetics, when it is a poly(glycerol) branched alkyl ether.
Most of the known nonionic surface active agents have their alkyl nuclears including a relatively short chain length or a double bond. This is because, in the case of long-chain alkyl groups, pearl-like crystals precipitate resulting from the Krafft points of the nonionic surface active agents, and lead to instability of the products. With the inventive solubilizers, there is no possibility of precipitation of crystals since they are based on polyglycerol and have a low melting point. In addition, it is also possible to obtain a solubilizing system even with the use of an alcohol with its straight-chain or branched alkyl being long, thus allowing product design that is more safe and more stable to oxidation.
The solubilized type lotion generally has a bubbling tendency and, once bubbled, bubbles continue to be present over a considerable period of time. It is said in view of both appearance and touch during hand-spreading that the less the bubbles, the better the quality would be. The inventive solubilizer is characterized by its fast rate at which bubbles break (hereinafter referred to as the defoaming rate). To substantiate this, a lotion sample in which perfumes are solubilized by poly(glycerol)(15)poly(1,4-oxybutylene)(14)-2-octyldodecyl ether and a control lotion sample in which the perfumes are solubilized by the known solubilizers [three kinds of poly(oxyethylene) base surfactants] were prepared to observe their defoaming state at 20° C. The lotion samples were charged into 30 ml-test tubes in amounts of 10 ml, and vigorously shaken 50 times in the vertical direction. The volume of bubbles was measured with the lapse of time to determine the amount of the remaining bubbles. FIG. 8 indicates that the hydrogenated castor oil poly(oxyethylene) adduct contributes to a faster defoaming rate among the known nonionic surfactants, poly(oxyethylene)(30)2-hexyldecanoate poly(oxyethylene)(20)oleyl ether and hydrogenated castor oil poly(oxyethylene)(50) adduct, and the inventive solubilizer is by far superior in the defoaming rate to that adduct.
The solubility of surfactants depends largely upon HLB. The optimum HLB for solubilization is taken as being 12-15. The substances to be applied over the skin of human beings, such as cosmetics, should be safe as much as possible. It is said that increases in molecular weight would be effective for safety. Increases in the molecular weight of nonionic surfactants may be achieved by increasing the number of moles of the hydrophilic groups added; however, too high a molecular weight causes that HLB may exceed the upper limit of the optimum range for solubilization.
With the inventive solubilizer, it is possible to increase only the molecular weight, while keeping the HLB constant in the desired range. This is because the inventive solubilizer includes a group allowing the HLB to shift to the lipophilic side, such as 1,4-butylene oxide.
The polyglycerol ether type compounds of the present invention, whether used as emulsifiers or solubilizers, can provide surface active agents which are safer than ever in view of stimulation to the skin.
To substantiate this, simple emulsions comprising liquid paraffin-water were prepared as samples, which contained 20% by weight of the inventive compounds [poly(glycerol)(16)poly(1,4-oxybutylene)(10)2-octyldodecyl ether and poly(glycerol(16)poly(1,4-oxybutylene)(10)stearyl ether] and the known sorbitan base, nonionic surfactants poly(oxyethylene)(20)sorbitan monostearate. The thus obtained emulsion samples are applied over the skin of rabbits to try primary irritation testing (percutaneous) for the comparison of difference in irritation.
In the testing, a total of 0.3 ml of the samples were administered to Angora rabbits in three equal doses at an interval of 24 hours. Four days after administration, estimations were made of irritation to the skin. Table 2 shows the results, from which it has been found that the irritating action the inventive compounds have is equivalent to, or less than, that of the sorbitan fatty acid esters which are said to be relatively safer. This implies that the inventive compounds are proved to be satisfactorily safe for use.
TABLE 2__________________________________________________________________________ Sample Invention Emulsion Poly (glycerol) (16) Poly Poly (glycerol) (16) Conventional EmulsionType (1,4-oxybutylene) (10) (1,4-oxybutylene) Using poly (oxyethylene)of test 2-octyldodecyl ether (10) Stearyl ether (20) sorbitan monostearate__________________________________________________________________________Erythema 0.30 0.40 0.39Vasodilation 0.43 0.94 1.11Edema 0.41 0.60 0.48ICP* 0.01 0.01 0.01Total 1.14 1.95 1.99__________________________________________________________________________ Primary irritation test (percutaneous) with Angora rabbit After 4 days For estimation, a range of 0 (no irritation) to 3.0 (strong irritation) i divided into 20 grades. The results are given by the average of 20 measurements *(Increased Capillary Permeability by Evans Blue Method)
As described above, the polyglycerol ether compounds of the present invention can provide nonionic surface active agents exceling in safety and stability, and added to a variety of cosmetics in the required amounts depending upon the kinds thereof. For instance, it is preferable that the inventive compounds are used as solubilizers for lotion products in an amount ranging from 0.1 to 10% by weight, and as emulsifiers for cream products, etc., in an amount ranging from 0.5 to 60% by weight.
Functioning as surface active agents, the inventive compounds may find use in various applications inclusive of detergents, soaps and pharmaceutics.
The solubilization of the inventive polyglycerol compounds and the cosmetic products containing them will now be explained with reference to the following, non-restrictive examples wherein the proportion of components is indicated by percentage by weight.
EXAMPLE 1
Emollient Cream
______________________________________(1) Poly(glycerol)(10)poly(1,4-oxybutylene) 3.0 (9)stearyl ether Poly(glycerol)(4)poly(1,4-oxybutylene) 2.0 (4)stearyl ether Stearic acid 5.0 Cetyl alcohol 3.0 Squalane 10.0 Bees wax 2.0 Spermaceti 1.0 Lanolin 2.0 Parabens (mixture of methylparaben and butylparaben) 0.3 Perfumes 0.3(2) Propylene glycol 7.0 Glycerol 4.0 Refined water 61.0______________________________________
(1) and (2) were heated to 70° C. (2) was added under stirring to (1). After the completion of reaction, the reaction product was uniformly emulsified in a homomixer, and cooled down to 30° C. in a heat exchanger.
EXAMPLE 2
Emollient Lotion
______________________________________(1) Poly(glycerol)(6)poly(1,3-oxy- 3.0 trimethylene)(5)stearate Stearic acid 2.0 Cetyl alcohol 1.5 Lanolin 2.0 Squalane 10.0 Antiseptics given amount Perfumes "(2) Propylene glycol 4.0 Sorbitol 4.0 Carboxyvinyl polymer 0.1 Refined water 63.4(3) 10% aqueous solution of triethanolamine 10.0______________________________________
(1) and (2) were heated to 70° C. (2) was added under stirring to (2). After the completion of reaction, the reaction product was uniformly emusified in a homomixer. (3) was slowly added under agitation to the emulsion for neutralization. Thus obtained product was cooled down to 30° C. in a heat exchanger.
EXAMPLE 3
Creamy Foundation
______________________________________(1) Poly(glycerol)(5)poly(1,4-oxybutylene) 3.0 (6)palmitate Stearic acid 4.0 Glycerol monostearate 3.0 Cetyl alcohol 1.0 Liquid paraffin 7.0 Glycerol tris-2-ethyl hexanoate 7.0 Antiseptics given amount(2) Refined water 55.0 Triethanolamine 1.0 Sorbitol 3.0(3) Titanium oxide 8.0 Kaolin 5.0 Talc 2.0 Bentonite 1.0 Coloring pigments given amount(4) Perfumes "______________________________________
Pigments (3) were mixed together and pulverized. (3) was dispersed in aqueous phase (2) heated to 80° C. (1) was solubilized by heating to 80° C., and gradually added to (2) for emulsification. The emulsion was cooled under stirring, and added with (4), followed by cooling down to 30° C.
EXAMPLE 4
Lotion
______________________________________(1) Poly(glycerol)(15)poly(1,4-oxybutylene) 1.0 (14)-2-octyldodecyl ether(2) Perfumes 0.4(3) 1,3-butylene glycol 2.5(4) Sorbitol 2.5(5) Ethanol 5.0(6) Distilled water 89.4(7) Methylparaben given amount______________________________________
At room temperature (6) was added under agitation to a solution obtained by solubilization of (1), (2), (3) and (7), followed by further addition of (4) and (5).
EXAMPLE 5
Solubilization of Jojoba Oil
______________________________________(1) Poly(glycerol)(16)poly(1,4-oxybutylene) 1.0 (8)2-hexyldecyl ether(2) Jojoba oil 0.3(3) Perfumes 0.4(4) 1,3-butylene glycol 5.0(5) Distilled water 68.3(6) Ethanol 5.0(7) Antiseptics given amount______________________________________
At room temperature (5) was added under stirring to a uniform solution of (1)-(4) and (7), followed by further addition of (6). | A novel randomly polymerized polyglycerol, polytrimethylene- or -tetramethylene-oxide condensate of an 8-36 carbon aliphatic alcohol or fatty acid useful as a non-ionic surface active agent. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority, under 35 U.S.C. §119, of European application No. EP 14165902.9, filed Apr. 24, 2014; the prior application is herewith incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
The present disclosure relates to an improved control valve. The present disclosure focuses on a control valve wherein the flow of a fluid is a function of the position of a throttle. More particularly, the control valve as disclosed herein achieves a flow rate that is substantially independent of the pressure at the outlet of the valve.
Flow control valves are commonly employed in HVAC (heating, ventilation, air conditioning) systems of buildings. These systems typically circulate a fluid such as water through a plurality of conduits in order to provide heating or cooling. The purpose of a flow control valve is to achieve a controlled flow of a fluid through the conduits of the system.
The amount of water flowing through the valve is essentially governed by the position of the throttle. A separate flow meter measuring the flow of water through the HVAC system may thus be dispensed with.
The amount of delivered energy is then calculated as the throughput of the fluid multiplied with the temperature drop in the system. The flow of water is determined from the position of the throttle and the temperature drop is measured separately. In the context of HVAC systems, the amount of energy is frequently measured in kWh.
U.S. Pat. No. 7,128,086 B2 was granted in 2006 and discloses a flow control valve. The valve according to U.S. Pat. No. 7,128,086 B2 contains a hollow piston 110 movable along an axis X 1 . A spring 160 exerts a force on the hollow piston 110 in the direction of the same axis X 1 . A rolling diaphragm is arranged on one side of the piston 110 . The rolling diaphragm is connected to the hollow piston 110 and separates an annular channel 109 from the inside of the hollow piston 110 . The annular channel 109 is in fluid communication with the inlet 106 of the valve through a reference passageway 180 . The inside of the hollow piston 110 is in fluid communication with the outlet 108 of the valve through apertures 192 of the hollow piston 110 . The valve also contains a channel that circumferentially surrounds the hollow piston 110 and is in fluid communication with the flow channel 104 of the valve.
The pressure in the annular channel 109 of this arrangement is the pressure p 1 at the inlet 106 of the valve. Similarly, the pressure inside the hollow piston 110 equals the pressure p 3 at the outlet 108 of the valve. The pressure p 2 in the chamber surrounding the hollow piston 110 is the same as the pressure inside the flow channel of the valve 104 .
The hollow piston 110 may move under the influence of the pressures p 1 , p 2 , p 3 and under the influence of the spring 160 . As soon as the corresponding forces are balanced, the difference between the pressures p 1 at the inlet and p 2 inside the flow channel predominantly determines the flow rate through the valve. The influence of the pressure p 3 at the outlet 108 of the valve is largely eliminated.
The arrangement as disclosed by U.S. Pat. No. 7,128,606 B2 requires an element 118 for guidance of the axial movement of the piston 110 . The piston guide needs to be mounted to the valve body and a seal 130 is necessary to separate the annular channel 109 from the inside of the hollow piston 110 . The seal 130 and the rolling diaphragm separate the annular channel 109 with the highest pressure p 1 from the inside of the piston 110 with the lowest pressure p 3 . The stresses on the seal 130 and on the rolling diaphragm are particularly high along its second convolution 138 . The piston 110 is movable against the guide 118 . Due to the stresses on the seal 130 and on the rolling diaphragm, an adequate choice of materials for these highly stressed parts becomes challenging.
The gap in between the rim 117 of the guide 118 and the sleeve 114 of the piston 110 needs to be narrow in order to prevent transverse movement of the piston 110 . Yet the fluid from the inside of the hollow piston 110 must reach the space in between the rim 117 and the second convolution 138 . The second convolution 138 will otherwise not be exposed to the pressure drop between the p 1 and p 3 . Extra design measures will be required to overcome the conflicting requirement of precise guidance through the rim 117 and of full pressure drop across the second convolution 138 .
The aim of the present disclosure is at least to mitigate the aforementioned difficulties and to provide a flow control valve that meets the aforementioned requirements.
SUMMARY OF THE INVENTION
The present disclosure is based on the discovery that technical constraints on a seal adjacent to a piston can be relaxed through an adequate pressure concept. The valve disclosed herein is configured such that the pressure inside the piston is the same as the pressure of an annular channel adjacent to the piston. This measure mitigates the difficulties involved in configuring a seal in between the annular channel and the piston. Further, the pressure concept of the present disclosure avoids extra measures to ensure an even distribution of pressure around a guide element.
The above problems are resolved by a pressure independent control valve according to the main claim of this disclosure. Preferred embodiments of the present disclosure are covered by the dependent claims.
It is a related object of the present disclosure to provide a pressure independent control valve wherein friction between the movable piston and the guide element is minimized.
It is another related object of the present disclosure to provide a pressure independent control valve wherein any hysteresis affecting the movement of the piston is negligible.
It is yet another related object of the present disclosure to provide a pressure independent control valve wherein a throttle controls the fluid throughput through the valve to the point where an additional flow meter can be dispensed with.
It is another object of the present disclosure to provide a pressure independent control valve configured for measuring a temperature drop across the valve.
It is yet another object of the present disclosure to provide a heating, ventilation and air-conditioning system with a pressure independent control valve according to this disclosure.
It is another object of the present disclosure to provide a building with a heating, ventilation and air-conditioning system comprising a pressure independent control valve.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a pressure independent control valve, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic, sectional view of a pressure independent control valve according to the invention; and
FIG. 2 is a graph showing a fluid throughput versus a pressure difference.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown various principal and optional components of a pressure independent control valve as per this disclosure.
The pressure control valve contains a valve body 1 with openings forming an inlet 2 and an outlet 3 . The inlet 2 and the outlet 3 allow a flow of a fluid through the valve. In a preferred embodiment, the fluid is a liquid. In a particularly preferred embodiment, the fluid flowing through the valve is water or a mixture containing water.
A flow channel 4 is arranged along the fluid path and in between the inlet 2 and the outlet 3 . At the inlet 2 of the valve, the fluid has a pressure of substantially p 1 . The pressure of the fluid at the outlet 3 of the valve is substantially p 3 . The (overall) pressure of the fluid inside the flow channel 4 substantially is p 2 .
A throttle 5 is movably mounted inside a seat 27 in between the inlet 2 and the flow channel 4 . The position of the throttle 5 may change by moving a stem 6 back and forth along the direction indicated by arrow 7 . In a particular embodiment, the stem 6 is rotatable around the axis indicated by the arrow 7 . In an alternate embodiment, the stem 6 is not rotatable around the axis indicated by the arrow 7 .
The throttle 5 effectively varies and limits the flow of the fluid through the pressure independent control valve. To that end, the body of the throttle 5 is permeable to the fluid.
A bearing 8 restricts the movement of the stem 6 against the valve body 1 . Accordingly, the walls of the valve body surrounding the throttle 5 and the bearing 8 act as guide elements for the throttle 5 .
The bearing 8 may be of the ball-bearing type and/or of the friction-bearing type. It is envisaged that the bearing 8 also seals the pressure independent control valve, so that no fluid will leak from the valve.
A hollow piston 9 is movably mounted inside another seat in the valve body 1 . The hollow piston 9 has a cover 10 that is exposed to the pressure p 2 in the flow channel 4 . It is envisaged that the shape of the cover may be uneven or may be substantially flat. Those parts of the hollow piston 9 that are exposed to the pressure p 2 inside the flow channel 4 are impermeable to fluid. Consequently, no fluid coming from the flow channel 4 will enter the hollow piston 9 .
It is envisaged that the cross-section of the hollow piston 9 may be circular, oval, triangular, quadratic, rectangular. The cross-section of the hollow piston may actually have any shape 9 that technically makes sense.
Any movement of the hollow piston 9 is restricted by the seat in the valve body. Preferably, the seat for the hollow piston 9 effectively restricts the movement of the piston 9 to directions towards or away from the throttle 5 . The walls of the seat may hold the hollow piston 9 either through a friction-type bearing and/or through a ball-bearing. It is envisaged that the bearing will allow essentially no fluid to flow through the passage in between the hollow piston 9 and the walls of the seat in the valve body 1 . It is also envisaged that the same bearing is optimized for low friction and/or for minimum hysteresis.
The pressure independent control valve contains a further guide element 11 for the hollow piston 9 . The guide element 11 is arranged opposite to a cover 10 and penetrates a bore through the hollow piston 9 . The bore through the hollow piston 9 provides a sleeve 12 that is substantially parallel to the wall of the guide element 11 . The sleeve 12 and the guide elements 11 essentially form a bearing. This bearing may be of the ball-bearing or of the friction bearing type. The passage between the guide element 11 and the sleeve 12 needs not be fluid-tight. It is envisaged that the bearing formed by the sleeve 12 and the guide element 11 is optimized for minimum friction and/or for minimum hysteresis.
The sleeve 12 and the guide element 11 restrict the movement of the hollow piston 9 in the same manner as the aforementioned seat in the valve body 1 . It follows that technical constraints as the accuracy of guidance either through the sleeve 12 or through the seat in the valve body 1 may be relaxed to some extent.
The guide element 11 is surrounded by a biasing member 13 . In a preferred embodiment, the biasing member 13 is a spring. In a yet more preferred embodiment, the biasing member 13 is a helical spring, in particular a helical compression spring. The biasing member 13 is mounted to an end 14 of the guide element 11 . In a preferred embodiment, the guide element 11 provides a head 14 with a substantially flat surface that compresses the biasing member 13 .
An annular channel 15 , in general terms a reservoir 15 , is arranged adjacent to the hollow piston 9 . The annular channel 15 is in fluid communication with the inlet 2 of the pressure independent control valve through a passageway 16 . The annular channel 15 is also in fluid communication with the inside of the hollow piston 9 . The inside of the hollow piston 9 and the reservoir 15 in this context form a chamber. The hollow piston 9 is in general terms a displaceable element 9 or part of a displaceable element that separates the chamber from the flow channel 4 . According to a particular embodiment, the displaceable element provides no holes, orifices or apertures that allow the chamber to be in fluid communication with the flow channel 4 . In other words, the displaceable element provides a simply connected surface within the topological meaning of the term simply connected.
One or several apertures 17 are located in the wall of the hollow piston 9 that separates the annular channel 15 and the inside of the hollow piston 9 . Since the inlet 2 , the hollow piston 9 , and the annular channel 15 are all in fluid communication, these parts ( 9 , 15 , 2 , 16 , 17 ) are exposed to substantially the same pressure p 1 .
A rolling diaphragm 18 contributes to separating the pressure p 1 inside the annular channel and the pressure p 2 inside the flow channel 4 of the valve. The rolling diaphragm 18 provides a seal in addition to the aforementioned bearing formed by the hollow piston 9 and the seat in the valve body 1 . In a preferred embodiment, the presence of the two seals implies that the technical constraints for each of the two seals may be relaxed to some extent. If the sealing effect of the rolling diaphragm 18 is sufficient, the interface between the piston 9 and the valve body 1 may be permeable to some extent. Consequently, a ball bearing may be arranged in between the hollow piston 9 and the valve body 1 . The arrangement will then experience even less friction and/or less hysteresis as the hollow piston 9 moves.
The rolling diaphragm 18 may be made of any suitable flexible material. In particular embodiments, the rolling diaphragm 18 is made of rubber and/or fabric coated rubber and/or biaxially-oriented polyethylene terephthalate (MYLAR®) and/or polyester film and/or metal foil.
During operation, the pressure p 1 will exert a force to drive the hollow piston 9 towards the throttle 5 . The biasing member 13 will urge the piston 9 in the opposite direction away from the throttle 5 . A width of a gap between a rim 28 and (the cover 10 of) the piston 9 is thus allowed to vary to some extent. The amplitude of the movement of the hollow piston 9 depends on the pressure difference between the inlet 2 and the flow channel 4 .
The position of the throttle 5 relative to its seat 27 and position of the hollow piston 9 relative to the rim 28 determine the throughput of fluid through the valve. These positions are substantially independent of outlet pressure p 3 , so that the valve achieves a flow rate which is essentially independent of outlet pressure p 3 . The same is indicated on FIG. 2 , where typical fluid throughput (axis 21 ) is plotted versus pressure difference (axis 22 ). The flow of fluid is essentially constant on the right hand side of a pressure difference 23 .
Preferably, the piston 9 provides a surface 10 to separate the chamber from the flow channel 4 and the same surface is larger than the corresponding surface provided by the diaphragm 18 . In a yet more preferred embodiment, the area of the separating surface 10 of the piston 9 is at least twice the separating surface of the diaphragm 18 . In a yet more preferred embodiment, the area of the separating surface 10 of the piston 9 is at least five times larger than the area of the separating surface of the diaphragm 18 .
In a particular embodiment, the pressure independent control valve also contains an adjusting bolt 19 . The adjusting bolt 19 connects to a head 14 of the guide element 11 via a telescopic stem 20 . By turning the bolt 19 it is possible to adjust the position of the head 14 of the guide element 11 . Since the head 14 also connects to the biasing member 13 , the bolt 19 can be used to adjust the bias applied by the member 13 .
The bolt 19 is employed to alter the balance between the pressure inside the piston 9 , the pressure in the flow channel 4 and the force applied by the biasing member 13 . An adjustment of the bias applied by the member 13 has an effect on the maximum throughput of fluid through the valve. The flow of fluid through the valve will depend on the gap between the hollow piston 9 and the rim 28 . By altering the balance of pressures and forces inside the valve, this gap will also change. Consequently, an adjustment of the bias will affect the maximum flow of fluid through the pressure independent control valve. Arrow 24 on FIG. 2 indicates possible changes in the rate of fluid flow due to an adjustment of bias.
Actually, the flow of fluid through the valve is independent of outlet pressure p 3 as soon as the pressure difference between input 2 and output 3 exceeds a threshold. Any difference between p 1 and p 2 is limited to the difference between p 1 and p 3 . The pressure difference p 1 −p 2 between the inlet 2 and the flow channel 4 cannot exceed that value. If the difference between p 1 and p 2 becomes too small, the flow of fluid through the valve will depend on the pressure difference between inlet p 1 and outlet p 3 . FIG. 2 illustrates this regime as a line 25 with positive slope.
As soon as the pressure difference 22 reaches the onset 23 of constant flow, the throughput of fluid through the valve will essentially be independent of outlet pressure p 3 . By changing the position of the adjusting bolt 19 , the pressure difference required to achieve constant flow will also change.
An adjustment of the onset 23 of constant flow and of maximum throughput offers distinct benefits where pressure independent control valves need be accurate within certain limits. This is often the case in applications where a control valve renders a separate flow meter obsolete. Pressure independent control valves are then required to produce constant flow over a given range of pressure differences. Constant in this context means that the flow of fluid through the valve is determined by the position of the throttle 5 .
In yet another embodiment, a pressure independent control valve provides a plurality of temperature sensors to determine temperature drop. The temperature sensors can, for instance, be arranged at the inlet and/or at the outlet of the valve. This particular embodiment is particularly useful for metering.
By changing the position of an adjusting bolt 19 , the onset of constant flow and hence the useful range of pressure differences of a control valves is set. Likewise, the maximum throughput of fluid through a valve will affect accuracy. Also, for a given building the maximum flow of fluid will depend on the characteristics of the HVAC system employed in that building. The adjusting bolt 19 thus allows a pressure independent control valve to be adapted to the particular HVAC system of a building.
It should be understood that the foregoing relates only to certain embodiments of the invention and that numerous changes may be made therein without departing from the spirit and the scope of the invention as defined by the following claims. It should also be understood that the invention is not restricted to the illustrated embodiments and that various modifications can be made within the scope of the following claims.
The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
REFERENCE NUMERALS
1 valve body
2 inlet
3 outlet
4 flow channel
5 throttle
6 stem
7 arrow indicating possible movements of the stem 6
8 bearing surrounding the stem 6
9 hollow piston
10 cover
11 guide element
12 sleeve
13 bias element
14 head
15 annular channel
16 passageway
17 aperture
18 rolling diaphragm
19 adjusting bolt
20 telescopic stem
21 axis for the flow rate through the valve
22 axis for the pressure difference
23 onset of constant flow
24 variation of maximum flow
25 proportional regime of flow rate versus pressure difference
26 variation of onset of constant flow
27 seat of the throttle 5
28 rim | A pressure independent control valve contains a valve body with an inlet, an outlet and a flow channel coupling the inlet to the outlet. A hollow piston is arranged in a seat in the valve body, such that the hollow piston is configured to move. The hollow piston has an enclosure, such that the pressure independent control valve maintains different fluid pressures in the flow channel and inside the hollow piston. The pressure independent control valve contains a chamber and a biasing member to urge the hollow piston towards the chamber. The chamber is in fluid communication with the inlet and with the inside of the hollow piston, such that the valve applies substantially the same pressure inside the annular channel, at the inlet and inside the hollow piston. | 6 |
PRIORITY CLAIM AND CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 11/972,543, now pending. The patent application identified above is incorporated here by reference in its entirety to provide continuity of disclosure. This application also claims priority to and the benefit of the filing of U.S. Provisional Patent Application Ser. No. 60/884,302 entitled Panel System.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a wall system comprising one or more posts and one or more panels which may be easily interconnected by unskilled labor providing a very cost effective wall system that can be quickly and inexpensively installed.
[0003] Wall systems are used for a variety of purposes, such as a fence in outdoor applications, or interior or exterior walls of a building for commercial, office or residential use. Wall systems typically include posts forming vertical structural members for corners where walls intersect typically at a right angle or intermediate the ends as structural members between adjoining panels that are coplanar. Both walls and fences may have various lengths and thus may be assembled from a plurality of intermediate posts and interconnected panels. Such wall systems may utilize pre-fabricated panels fabricated from a variety of materials or the panels may be assembled on site. A number of means for connecting the panels to a post have been utilized including fasteners such as rivets, screws, and nails, or in the case of metal, posts and panels, by welding, brazing or similar metal joining methods.
[0004] Fences are typically constructed from wooden materials, utilizing wooden fence posts and panels of wooden construction. The fabrication of the panel may be on site by using upper and lower stringers between a pair of spaced apart posts and then assembling wooden boards between the stringers to form the panel. Or the panel may be prefabricated as a single unit having upper and lower rails and vertical end portions fastened at their upper and lower ends to the rails with the center portion of the panel comprising a variety of materials such as wood slats, arranged in vertical or horizontal position, and forming a solid surface or spaced apart slats or boards. The panel may also be constructed of a variety of materials other than wood.
[0005] Despite the use of wall systems in various applications for many years, the present wall system has advantages over such prior art systems as will become clear from the following description.
SUMMARY OF THE INVENTION
[0006] This invention comprises a wall system including one or more posts and panels, each panel having vertical end portions with a given thickness, each post comprising a first elongated substantially flat member, a second elongated substantially flat member attached at one proximal longitudinal edge to a first lateral location adjacent one longitudinal edge of the first member, a third elongated substantially flat member attached at one proximal longitudinal edge to the first member at a laterally spaced location from the first location, the distal edges of the second and third elongated members spaced a predetermined distance that is less than the thickness of the panel end portions, and at least one of said second or third elongated flat members being resilient, whereby the end portion of the panel may be inserted between the distal edges of the second and third elongated members and is clampingly retained therebetween.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention will be further understood from the following description with reference to the drawings in which:
[0008] FIG. 1 illustrates an elevation view of one embodiment of a wall system in accordance with the present invention;
[0009] FIG. 2A is an elevation view of one embodiment of a building having walls constructed in accordance with the present invention;
[0010] FIG. 2B is a front elevation view of the building shown in FIG. 2A ;
[0011] FIG. 3 is a sectional view of one embodiment of a post constructed in accordance with the present invention;
[0012] FIG. 4 is a sectional view of a second embodiment of a post;
[0013] FIG. 5 is a sectional view of the embodiment of the post showing the panel and post in fixed relationship;
[0014] FIG. 6 is a sectional view of a third embodiment of a post;
[0015] FIG. 7 is a sectional view of a fourth embodiment of a post;
[0016] FIG. 8 is a sectional view of the post shown in FIG. 6 with the vertical end portions of a wall panel retained by the post;
[0017] FIG. 9 is a sectional view of a fifth embodiment of a post;
[0018] FIG. 10 is a sectional view of a sixth embodiment of a post;
[0019] FIG. 11 is a sectional view of a pair of posts showing a hinged panel and portions of two adjacent panels;
[0020] FIG. 12 is a sectional view of a seventh embodiment of a post;
[0021] FIGS. 13A , 13 B, 13 C and 13 D show details of one embodiment of cross members and anchoring structure of a post;
[0022] FIG. 14 is a sectional view of an eighth embodiment of a post;
[0023] FIG. 15 illustrates the biasing member shown in FIG. 14 ;
[0024] FIG. 16 is a sectional view of a ninth embodiment of a post showing the use of the biasing member in FIG. 15 ;
[0025] FIG. 17 is a sectional view of a tenth embodiment of a post;
[0026] FIG. 18 illustrates the biasing member of the embodiment shown in FIG. 17 ;
[0027] FIG. 19 is a sectional view of an eleventh embodiment of a post;
[0028] FIG. 20 is a sectional view of a twelfth embodiment of a post;
[0029] FIG. 21 illustrates the biasing member of the embodiment shown in FIG. 20 ;
[0030] FIG. 22 is a sectional view of a thirteenth embodiment of a post;
[0031] FIG. 23 is a right side elevation view of the embodiment shown in FIG. 22 ;
[0032] FIG. 24 is a vertical sectional view of the thirteenth embodiment shown in FIG. 22 ;
[0033] FIG. 25 is a sectional view of a fourteenth embodiment of a post;
[0034] FIG. 26 is a sectional view of a fifteenth embodiment of a post; and
[0035] FIGS. 27A-27D are sectional views of the fifteenth embodiment in various combinations.
DETAILED DESCRIPTION
[0036] The wall system of the present invention is useful in many applications, two of which are shown in FIGS. 1 and 2 . In FIG. 1 , the wall system comprises a portion of a fence 10 and as shown comprises three identical posts 20 and two identical wall panels indicated at 30 . The posts 20 are vertically oriented and are spaced apart so as to received the panels 30 . The panels 30 are of a general rectangular configuration having two vertical end portions that engage the posts 20 . The wall panels may be fabricated from a wide variety of materials including metal, plastic, fiberglass, composite materials, or other suitable materials which may be formed in a single monolithic panel, or comprised of numerous individual longitudinally extending horizontal or vertical slats formed from material such as wood. Preferably, the panels are pre-fabricated and available in various heights and lengths as well as different thicknesses depending upon the application and other structural requirements of the panel.
[0037] The posts 20 for the fence 10 are embedded in the soil either directly or through an anchoring structure 40 which may comprise a concrete footing 42 poured into an opening in the ground and retaining a post 20 which has its lower end embedded in the concrete 42 as will be explained in greater detail in reference to FIG. 14 . Depending upon the type of fence and the environmental conditions it may be desirable to strengthen the wall panels through the use of cross wires, bars, or straps such as shown at 45 . It will be understood by those having ordinary skill in the art that cross bracing may be unnecessary and it will also be appreciated that there are a variety of anchoring structures that may be used for the post of the fence 10 .
[0038] In FIGS. 2A and 2B there is shown another application of the wall system of the present invention embodied in a simple building 50 having four walls 52 one of which is illustrated in FIG. 2A and one of which is illustrated in FIG. 2B . The building may have a pitched roof although the roof construction may be flat, or various other architectural configurations. The floor of the building is raised off the ground. As shown in FIG. 2A , the wall 52 may include three panels, 54 , each of which has a generally rectangular configuration. The building floor is shown at 56 and is of conventional construction. The wall 52 includes four posts, two of which at 58 are intermediate and frame the center panel 54 . The corners of the building 50 have posts 60 . The corner posts 60 are embedded in the anchoring structure such as that shown at 40 in FIG. 1 . The floor 56 of the building 50 may be additionally supported by short pillars 62 attached to the floor 56 and embedded in an anchoring structure such as at 40 .
[0039] The front elevation view shown in FIG. 2B illustrates that the wall 53 may also comprise three panels one of which is similar to panel 54 , one of which is a door 64 , and one of which comprises a sliding panel 66 . The door 64 may be constructed of glass. Panel 66 is mounted on tracks and may be moved so as to cover the door 64 exposing an additional panel such as 54 not shown in FIG. 2B since it is behind sliding panel 66 . The wall 53 includes at the corners the two posts 60 as shown in FIG. 2A . Door panel 64 may be constructed so as to open on hinges as will be described in conjunction with FIG. 11 , or may be slidable. The door 64 is framed by posts which will also be described in FIG. 11 . The panel 54 has a post 58 spaced apart from the post 60 . The panel 66 has post members 58 that attach to a top rail and a bottom rail.
[0040] It will therefore be appreciated that the wall system of the present invention may be used in various applications including but not limited to fences and building sidewalls. The wall system may comprise one or more panels each of which are attached to a post that clamps and retains the vertical end portions of the panel. It will also be appreciated from these illustrations that the wall system may comprise a flat wall or two walls that form a corner. As will be described below, the walls may be oriented with respect to a post so as to radiate in four directions as may be desirable in certain applications and is described in greater detail in reference to FIGS. 9 and 10 .
[0041] The post of the wall system of the present invention may be rendered in various embodiments and these will now be described and those of ordinary skill in the art will appreciate that the different configurations may be suitable for various wall configurations and thus will meet a large variety of applications for wall systems. FIG. 3 illustrates a first embodiment of a post 80 of the present invention, shown in section, and comprising two elongated substantially flat structural members that in this embodiment define plates, a first plate 82 , and a second plate 84 that are attached or joined along their longitudinal proximal edges at an angle of substantially 90° at a first lateral location. The post 80 has a third elongated substantially flat member 86 attached at its proximal longitudinal edge 88 to structural plate 82 along a vertical line that is laterally spaced from the intersection of plates 82 , 84 and forms an acute angle with plate 82 . In this embodiment, the third elongated flat member 86 is resilient and defines a biasing member. The word “bias” is used to denote the force that arises when a resilient member at rest is forcibly displaced; a “biasing member” is one that is made of resilient material, in whole or in part, that when deflected will apply a restoring force against the source of deflection. When a biasing member is spaced from a fixed member or another biasing member and an object is placed between such member that displaces or alters the position of the biasing member at rest, the biasing member or members will clamp the object with a force that resists removal of the object. The word plate means a substantially flat elongated member that, relative to a biasing member has more resistance to elastic deformation thus providing structural strength to the post; the resistance may be due to the thickness of the member(s), type of material or other factors that affect the modules of elasticity. The distal edge 90 of biasing member 86 is spaced from the elongated substantially flat structural plate 84 at a pre-determined dimension, distance or space shown at 92 . At least a portion of biasing member 86 is resilient and biases the distal edge 90 toward the structural plate 84 for the purpose to be described.
[0042] FIG. 4 shows a second embodiment of a post 100 adapted to hold two panels in coplanar relationship comprised of two joined subassemblies 102 and 104 which may be used to vertically support two in-line panels. Post subassembly 102 comprises at least two elongated substantially flat structural plates 106 , 108 attached along their proximal longitudinal edges at an angle of substantially 90° as in the embodiment of FIG. 3 . Post subassembly 102 additionally includes at least one elongated V-shaped member 110 that includes a biasing member 112 that comprises one leg of the V-shaped member 110 attached to a second leg 114 that is fixedly attached to the substantially flat structural plate 108 . Holding member 112 has a distal end 116 and is similar to holding member 86 as shown in FIG. 3 except that the proximal vertical edge of the holding member 112 is attached to the second leg 114 of V-shaped member 110 which in turn is attached to structural member 108 . In this second embodiment, the proximal edge 118 of holding member 112 is also laterally spaced from structural member 106 a pre-determined lateral distance greater than the distal edge 116 of biasing member 112 with respect to structural plate 106 . It will be readily understood by those having ordinary skill in the art that subassembly 104 of the second embodiment 100 is identical to subassembly 102 but allochirally oriented with respect to subassembly 102 . It will also be understood that the subassembly 102 may be used alone at the end of a wall, like post 80 . Thus, it will be unnecessary to describe the elements that comprise subassembly 104 . Moreover, the two longitudinally extending flat plates 106 , 108 may be integral, such as a common “angle iron” or L-shaped extrusion.
[0043] In FIG. 5 , the second embodiment of FIG. 4 is shown in combination with two wall panels having vertical end portions 120 . With attention drawn to subassembly 102 , it will be seen that the end portion 120 is held between the elongated substantially flat structural plate 106 and biasing member 112 . The biasing member 112 is, all or a portion, resilient and biases the distal edge 116 toward structural plate 106 . Since a portion of biasing member 112 is resilient, distal edge 116 is positionally altered when the panel end portion is forced between the distal edge 116 and flat plate 106 because the distance 92 is less than the thickness of the wall panel end portion 120 whereby the end portion is clamped and retained between the holding member 112 and the flat structural plate 106 . It will therefore be appreciated that the biasing force of the clamping structure portion of member 112 will securely retain the end portion of the panel and thus the panel itself in engagement with the post 100 without requiring any fasteners, glue, welding, or other similar methods for retaining two elements in fixed relationship. There is no requirement for any specialized tools to engage the wall panel with a post obviating the need for expensive assembly tools such as drills, welding equipment, glue dispensers, or the like.
[0044] A third embodiment of a post 130 comprises two subassemblies, 102 , 104 that are identical to one another and also to the subassemblies, 102 , 104 in the second embodiment shown in FIG. 4 . However, in FIG. 6 , the subassembly 104 has been reoriented so that structural plate 106 of subassembly 104 is attached to structural plate 108 of subassembly 102 as compared to the orientation of the subassemblies 102 , 104 in FIG. 4 . By reorienting subassembly 104 the post 130 is suitable for a corner as shown in FIG. 8 .
[0045] FIG. 7 shows a fourth embodiment of a post 140 comprising post subassemblies 142 and 144 . Subassembly 142 is identical in all respects to post member 80 shown in FIG. 3 . Thus, subassembly 142 includes a first elongated substantially flat structural plate 82 and a second structural plate 84 intersecting along their longitudinal edges at an angle of substantially 90°. An elongated substantially flat member 86 is attached at a proximal longitudinal edge 88 to structural plate 82 along a vertical line laterally spaced from the intersection of plates 82 and 84 and having a distal edge 90 spaced from the structural plate 84 so as to define a predetermined space 92 . Member 86 is formed of resilient material and defines a biasing member. The embodiment 140 has an additional subassembly 144 , identical to subassembly 142 , but oriented such that when wall panels are inserted and clamped into the biasing member and clamping structure of post members 142 , 144 the panels will be oriented in a 90° or orthogonal position. Comparing the fourth embodiment in FIG. 7 to the third embodiment in FIG. 6 it will be appreciated that the difference is that post 140 in FIG. 7 has subassemblies 142 and 144 that are identical to post 80 in FIG. 3 whereas the fourth embodiment 130 in FIG. 6 has subassemblies members 102 , 104 identical to those shown in FIG. 4 .
[0046] In FIG. 9 , there is a fifth embodiment, post 150 , comprising a four-way juncture for four wall panels the end portions of which are shown at 120 . With reference to FIG. 4 , it will be seen that post 150 comprises four subassemblies, identical to subassemblies 102 and 104 shown in FIG. 6 and an additional two subassemblies 152 , 154 which are identical in all respects, other than orientation, to subassemblies 102 , 104 .
[0047] In FIG. 10 , a sixth embodiment of a post is shown at 160 comprising the four subassemblies 102 , 104 , 152 and 154 shown in FIG. 9 oriented such that the structural member 108 of subassembly 154 and 106 of subassembly 104 are joined back-to-back and structural members 108 of subassemblies 104 and 154 are joined back-to-back while structural member 106 of subassembly 154 is joined to structural member 108 of subassembly 102 back-to-back. Thus the four-way post in FIG. 10 orients the four panels in a cross configuration as in FIG. 9 but the subassemblies 102 and 154 panel end portions are spaced from one another a lateral distance equal to the width of structural plate 108 .
[0048] In FIGS. 11A and 11B , it will be seen that a fence may be provided with a gate, or a building may be provided with a door, by using the posts as shown in any of the previous embodiments, first through fourth. Specifically, the door or gate 179 includes a panel 171 with a door handle assembly indicated generally at 172 . As seen in FIG. 11A , one end 173 of panel 170 is retained in a subassembly 102 and the adjacent fixed wall panel 174 has an end 175 retained by a second subassembly 102 which are of course identical in construction but oriented so as to receive a panel from the left rather than the right. A hinge 176 is positioned between structural plates 108 of the two post members 102 . At the opposite end of panel 171 , as seen in FIG. 11B the end portion 177 is retained in a post member 102 that is oriented in the same direction as post member 102 that engages panel 174 by retaining end portion 175 . The fixed wall section 178 adjacent to the end 177 of panel 171 has an end portion 179 received and retained by a second post member 102 oriented 180° to post member 102 that retains end portion 177 of door or gate panel 171 .
[0049] FIG. 12 shows a seventh embodiment of a post 250 suitable for a corner. This embodiment shows two subassemblies, each identical to member 80 shown in FIG. 3 . Each of the posts 80 includes substantially flat elongated structural plates 82 and 84 as well as a biasing member 86 . The vertical end portion 120 is clampingly engaged between the structural plate 84 and the biasing member 86 . In order to fix the two plate members 82 in a right angle configuration, there is provided a reinforcement tube 252 that attaches on one face to plate 82 of one of the subassemblies 80 and on another face to the plate 82 of the second subassembly 80 .
[0050] FIGS. 13A-13D show the details of the termination of the cross members (beams, straps or wires) at the bottom and top of a post 260 . Post 260 includes two subassemblies 262 and 264 having their structural plates 266 and 268 attached back-to-back so as to form a T-cross section post as shown in FIG. 5 . Mounting structure 40 includes an L-shaped post base 41 that may be embedded in concrete 42 (see FIG. 1 ). The L-shaped member, may comprise a round bar bent at a 90° angle at its lower end and at its top end is secured by welding or the like to an angle iron 270 having a leg 272 horizontally disposed and a vertically disposed leg 274 having a slot 276 as seen best in FIG. 13C which together with fasteners permit the post to be vertically adjusted relative to the anchoring structure. A pair of diagonally oriented cross beams 280 are attached to post members 262 and 264 and at their upper end to two identical post members 290 , 292 as seen in FIG. 13D . This particular anchoring structure is highly suitable for use of the wall system as a fence and the cross beams are structurally desirable where wind or other forces must be resisted by the wall system.
[0051] FIG. 14 shows an eighth embodiment of a post 300 for the wall system of this invention. The cross section of FIG. 14 shows a first elongated substantially flat member in the form of a structural plate 302 disposed in a vertical position when in use. A second elongated substantially flat member 304 is attached at its longitudinal proximal edge 306 to structural plate 302 . A third elongated substantially flat member 308 is attached at its proximal longitudinal edge to said structural plate 302 so that the distal longitudinal edges 312 , 314 of biasing members 304 , 308 define a predetermined space or distance 316 . In post 300 , the second and third flat members 304 , 308 are formed from resilient material and define biasing members. FIG. 14 also shows that the post 300 may be used as a post in an in-line wall by including a biasing member 320 attached to the structural plate 302 at 322 and having a distal end 324 . Similarly, opposite the biasing member 308 there may be a biasing member 326 attached to structural plate 302 at 328 and having a distal end 330 which, together with distal end 324 of biasing member 320 , defines a space 332 identical to space 316 .
[0052] As shown in FIG. 15 , the biasing members 304 , 320 (and similarly the biasing members 308 and 326 ) may be formed from a single resilient sheet of material which has a central region 340 that complements the shape of the vertical end portions 342 and 344 of structural plate 302 . Structural member 302 is provided with a pair of longitudinally extending notches on opposite sides of structural plate 302 spaced laterally inwardly from the edge of the end portions 342 and 344 of structural plate 302 . The biasing member comprising the sections 304 , 320 and 340 , at the point at which the biasing members 304 and 320 connect to the central portion 340 , define ridges at 350 that are spaced apart a distance less than the thickness of the end portions of structural plate 302 . To assemble the post 300 , the biasing member 304 , 320 and 340 is forcibly pushed over the longitudinal end 342 of structural plate 302 until the ridges 350 snap into the vertical notches in the opposite faces of structural plate 302 . It will therefore be appreciated that when assembled, the space 316 defined by the distal ends 312 , 314 of biasing members 304 and the space 332 defined by the distal ends 324 , 330 of biasing members 320 , 326 is less than the thickness of the end portion of a panel that may be inserted between the biasing members to thereby firmly clamp the end portion of the panel to the post 300 .
[0053] FIG. 16 shows a ninth embodiment of the invention, a post 350 , in which the biasing member 304 , 320 , 340 , as shown in FIG. 15 and described above is used in conjunction with two structural subassemblies 360 , 362 the former comprised of first and second flat members 364 , 366 attached at one longitudinal edge to form the L-shaped subassembly 360 comprised of first and second flat members 368 , 370 attached at one longitudinal edge to form the L-shaped subassembly 362 . The L-shaped subassemblies are attached back-to-back. The exposed surfaces of flat members 366 , 370 have a longitudinally extending notch as in the embodiment of FIG. 14 . The clip is then inserted over the free ends of legs 366 , 370 until the ridges 350 snap into the notches in the respective flat members or legs 366 , 370 . Accordingly, the ninth embodiment post 350 comprises elongated substantially flat structural members 366 and 370 of L-shaped subassemblies 360 , 362 , a substantially flat biasing member 304 attached at a proximal edge through the interconnection of ridges 350 with the notches in members 366 , 370 , and an additional elongated substantially flat structural member 368 attached at its proximal longitudinal edge to member 370 so as to define a predetermined space 316 for receiving and clamping the vertical end portion of a wall panel.
[0054] It will therefore be seen that in the embodiment shown in FIG. 14 the end portion of the panel is clamped between the distal edges 312 , 314 of biasing members 304 and 308 whereas in the ninth embodiment of FIG. 16 the end portion of the panel is inserted in the space 316 so that the distal end 312 of biasing member 304 will clamp the end portion of the panel against member 368 of L-shaped subassembly 362 that comprises post 350 . In one case the panel is clamped between two biasing members, and in the other, between one biasing member and one structural member as in the embodiments shown in FIGS. 3-10 , 12 and 14 - 16 . Of course, the clamping force can be adjusted to be equal if desired. The clamping force can be altered by a change in material, material thickness, or the pre-selected dimension between the biasing member distal edge and the adjacent biasing or structural member.
[0055] FIGS. 17 , 18 and 19 are similar views to FIGS. 14 , 15 and 16 showing a tenth embodiment 375 again comprising the same components, i.e., biasing member 304 , 340 and 324 , formed as a single piece from a single sheet of resilient material and a structural member 302 . However, post 375 has a different ridge and notch engagement structure but to effect the same result. The post 375 in FIG. 17 may also be configured, similar to FIG. 16 , as an eleventh embodiment, post 385 ( FIG. 19 ), so as comprising two L-shaped subassemblies 390 , 392 .
[0056] In FIG. 20 a twelfth embodiment 400 of the invention is shown in cross section. The post 400 includes an elongated substantially flat structural plate 402 , that in use, is vertically disposed. Two biasing members 404 , 406 are configured, as seen best in FIG. 21 as a shallow V-shaped resilient member comprising two resilient flat members 412 , 414 that intersect at an obtuse angle. The biasing member 404 comprises resilient flat members 408 , 410 and is identical to the biasing member 406 . The center section of the biasing members 404 and 406 , are secured to the end portions 416 , 418 of plate 402 in a permanent manner such that the distal ends of the wings 408 , 412 are spaced a predetermined distance, equivalent to the distance between the distal ends of the biasing members 410 , 414 on the opposite side of the structural plate 402 . In the preferred embodiment, the obtuse angle between the wings 412 , 414 and 408 , 410 is 160°. Depending upon the material of the structural plate 402 , and the material of the biasing members 404 and 406 , if made of metal, they may be attached by welding, spot welding, brazing, or other metal joining technique. Alternatively, the entire post may be extruded as a single integral piece, cut off in selected lengths. If the V-shaped resilient member and structural plate are formed of non-metallic material, they may be attached by various methods including glue or may be pultruded as a one-piece integral component. Alternatively, regardless of the material the resilient members and structural plate may be jointed with fasteners.
[0057] Referring to FIGS. 22-25 , a thirteenth embodiment of the invention, post 440 , is shown in FIG. 22 comprising a generally U-shaped member including a pair of substantially flat biasing members 442 and 444 that are attached at their longitudinal edges to base member 446 or may be formed from a single sheet of resilient material bent to the configuration shown. The base member 446 is shown in a front elevation view in FIG. 23 and in a series of sectional views in FIG. 24 illustrating the joining of the components of the post 440 . The post 440 base member 446 has an interlocking structure comprising a cleat 450 that is stamped out of the base member leaving an opening 452 . In a preferred embodiment of the post 440 , fabricated from metal, the distance between the adjoining openings 452 , 456 and cleats 450 , 454 may be on the order of six inches. It will be understood by those of ordinary skill in the art that a post 440 may be combined with an identical post 480 , as shown in FIG. 25 as subassemblies to comprise the post 500 . The subassemblies may be connected back-to-back to form a structural member by inverting one of the subassemblies to the position shown at 448 in FIG. 24 permitting the base member 446 of subassembly 440 to interconnect or interlock with the base member 446 of subassembly 480 . Alternatively, the two base members 446 could be attached back-to-back with fasteners, glue, welding or the like. After assembly, the post 500 comprising interlocked pairs of subassemblies 440 and 480 has the same sectional configuration as the post 400 as shown in FIG. 20 . The two layers of base member 446 from subassemblies 440 and 480 , by doubling the thickness of the base members, provides a substantially flat structural plate as shown at 482 .
[0058] Post 440 may be varied so that the interlocking structure is formed in one or more than one of the three resilient members as shown on post 550 in FIG. 26 . With interlocking structure on two of the resilient members, the subassembly of FIG. 26 may be combined and arranged in various configurations such as those shown in FIGS. 27A-27D . The post 550 as shown in FIG. 26 has three resilient members 552 , 554 , and 556 . 556 comprises the base member comparable to the base member in FIG. 22 ; however, base member 556 is attached to resilient member 554 at a right angle whereas resilient member 552 is attached at an acute angle. Base 556 and biasing member 554 each have interlocking structure as described in reference to FIGS. 23 and 24 . The post 550 may be used alone as an end post for a wall. As seen in FIG. 27A , two posts identical to post 550 may be interlocked at bases 556 so as to form a post suitable for an inline connection of panels in a wall system. In FIG. 27B , two posts 550 are oriented so as to form a corner post. In FIG. 27C , three posts 550 are arranged so as to provide both a right angle or corner post as well as an inline post. And finally, as shown in FIG. 27D , there are four posts 550 arranged so as to form a four-way corner similar to that shown in FIG. 9 . Thus, it will be apparent to one of ordinary skill in the art that a wide variety of posts can be configured from the single post 550 as may be desirable for various applications of a wall system. An advantage of the post shown in FIGS. 22-27 is that the U-shaped elongated structures are formed from a single thickness of material and thus may be suitable for fabrication by bending a flat sheet of metal without requiring any welding or similar means for attaching two of the resilient members to a third.
[0059] It is to be understood that the invention is not limited to the exact details of construction, assembly, materials, or the many embodiments shown and described, as obvious modifications and equivalents will be apparent to one skilled in the art. As noted above, various types of material may be used. Furthermore, the wall system, including the post members and panel, are scalable such that panels of various thickness may be used in accordance with the invention for applications where the wall system is intended to provide a building wall that is sufficiently thick and of a type of material that provides insulation, noise suppression, and the like. As also indicated above, a panel may be formed from glass so as to provide for a window when the wall system is used for building construction. It will also be understood that a wide variety of anchoring structures may be used for vertically supporting the wall system depending upon the application of the wall system, that is, when used as a fence or a building wall. Accordingly, the invention is therefore to be limited only by the scope of the appended claims. | A wall system suitable for use in applications such as a fence or a wall of a building which comprises posts and panels which are interconnected or interengaged so that the wall may comprise a series of inline panels or corners formed by two panels and a single post, the interconnection or interengagement of the panels being effected without use of mechanical fasteners, glue, welding, or similar modes of attachment. | 4 |
RELATED APPLICATION
This application claims priority pursuant to 35 U.S.C. 119 based upon U.S. provisional application Serial No. 60/192,214 filed Mar. 27, 2000, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a system and method for optimizing the charging of batteries in electric and hybrid vehicles.
BACKGROUND OF THE INVENTION
Electric vehicles have an electric motor as a power source that uses batteries or fuel cells as the source of energy. Hybrid vehicles generally have two different power sources to drive the vehicle, usually one being an internal combustion engine and the other an electric motor that is powered by an energy source, such as batteries. The batteries are of the rechargeable type. Other types of energy sources such as super-capacitors also can be used. Both kinds of vehicles also are usually equipped with a regenerative system which converts vehicle kinetic energy into electrical energy to recharge the energy source, here considered to be one or more batteries. For example, as the vehicle undergoes braking, the braking force drives the electric motor of the vehicle operated as a generator, or drives a separate generator, that is used to generate electrical energy (current) to recharge the batteries. The electric energy produced by the regenerative system is stored in the vehicle batteries and is used to power the vehicle electric motor when needed.
When batteries are used in electric or hybrid vehicles, they are generally maintained in a state of charge (SOC) range at which the battery internal resistance (IR) is minimal, especially in a charging condition. This is done for the purpose of preventing excessive heating and to have high efficiency of charging, meaning that most of the energy goes to charging and very little is wasted in heating due to the high impedance of the battery, from the regenerative braking system. For example, for lead-acid batteries, these often being used in electric and hybrid vehicles, the batteries are kept at a relatively low SOC level of around 60%-65%. However, batteries tend to degrade faster under the condition of prolonged time in undercharged (low SOC) condition. For example, lead acid batteries tend to become sulfated and thereby have a shortened battery life.
Normally, it has been believed in the state of the art that when an electric or hybrid vehicle battery is above 70% SOC that the charge is accompanied by an undesirable overcharge gas evolution reaction. This is particularly true for lead acid batteries. I have determined that this holds true only when the battery is charged after it has been allowed to reach an equilibrium state. A battery reaches an equilibrium state after it is allowed to rest (no charge or discharge) for a period of time, for example, about 2-3 hours in a lead acid battery. By looking at the battery in situ current voltage characteristics, it can be determined if the battery is at equilibrium or not. This is done by determining if a current is present, whether positive or negative, and if it is, the battery is not in equilibrium. Similarly, if the voltage is above the upper limit or below a lower limit it is not in equilibrium.
In electric and hybrid vehicles, the regenerative energy is dumped (charged) into the battery when it is not at equilibrium. Generally, the battery keeps discharging as it is used to power the electric motor until the instant when the brakes are applied and at this time the regenerative energy is dumped into the battery. Typically, in the present state of the art, even though a battery of an electric or hybrid vehicle is charged before it reaches a state of equilibrium while in the vehicle by the regenerative system, the SOC value is still held at about 65%. That is, using present technology, the amount of the regenerative energy supplied to charge the battery is controlled as a function of battery SOC so that the battery SOC does not exceed 65%.
Accordingly, a need exists to control the charge of a battery in an electric or hybrid vehicle to place and maintain it at a higher level of SOC.
BRIEF DESCRIPTION OF THE INVENTION
I have determined that a battery can be charged at very high efficiency if the battery is charged immediately after a pulse type discharge or a continuous discharge. In an electric or hybrid vehicle, the continuous discharge would use the batteries as a source over a Is period of time to power the vehicle electric motor. The pulse would be a short burst of use of the vehicle electric motor. It has been found that when a battery is discharged by current pulses or continuous current, it can be immediately charged up to about 80% of the energy taken out during the discharge. This can be accomplished even if the battery SOC is above 80% when the discharge is stopped. It also has been found that a battery can be charged to a higher SOC than the 65% value that is currently used in electric and hybrid vehicles.
In accordance with my invention, the regenerative system is operated to immediately charge the battery upon discharge being terminated. The charging is carried out to the maximum extent possible, the charge current limitation being predominantly determined by the circuit characteristics of the battery charging system, such as the current carrying capacity of the wires and other components. Hardware control elements in the battery charging system are provided to prevent the charging current from rising above this safe level. Normally, charging current will be limited automatically to a smaller value than the safe limit when the battery voltage is controlled to a desired level.
In any system, as a battery is charged, its SOC increases over time. Thus, a battery can be charged to a high SOC value merely by continuing the charging time. In the present invention, the dumping of the regenerative energy into the battery for its charge is controlled as a factor of battery charge current and battery voltage limitations instead of the SOC, which is used in the present systems to achieve and maintain a higher level than the 65% SOC that is currently used.
In a preferred embodiment of the invention, a higher SOC is obtained. As is known, at a certain point during charge, a battery will start to produce gas. I have determined that there is a relationship between the current and voltage of the battery during charging and the time at which the gas point is reached. In accordance with the preferred embodiment of my invention, the charge voltage is monitored and is limited based on the battery gas point characteristics, such as Igas and Vgas. At the gas point, at least for a lead-acid battery, the SOC will be higher than 65%, often in the range of 80%-90%, depending on the battery construction. The charging is limited or terminated before the gas point is reached. The gas point parameters may be determined from battery parameters other than the in situ current-voltage characteristics. For example, the battery voltage during charging or rate of change of battery internal impedance may be used to detect the gas point.
By following guidelines listed above, hybrid and electric vehicle batteries can be charged at greater efficiency when not in a state of equilibrium and also operated at a higher level of SOC, for example, around 80% SOC, and perhaps even up to 90% SOC. This contrasts with the present 60%-65% SOC for present day hybrid and electric vehicle batteries. This higher SOC level of operation results in longer battery life and better fuel efficiency in the case of hybrid vehicles.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a method and apparatus for controlling the charging of batteries in electric and hybrid vehicles to an optimal SOC value.
Another object is to provide a method and system for charging batteries in electric and hybrid vehicles in which the batteries are charged at a high current level after a continuous discharge or pulse discharge under dynamic operating conditions to a high level of SOC as determined by the battery voltage level during charge.
Yet another object is to provide a method and system for optimizing the charging of batteries in electric or hybrid vehicles in which charging is controlled to bring the batteries to a relatively high level SOC.
Still a further object is to provide a method and system for charging the batteries in electric or hybrid vehicles to a relatively high level SOC without exceeding the gas point of the batteries.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become more apparent upon reference to the following specification and annexed drawings in which:
FIG. 1 is a schematic diagram of a typical apparatus to be used for optimizing the performance of the batteries in an electric or a hybrid vehicle;
FIG. 2 is a graph showing battery cell voltage and impedance related to its gas point and charge time;
FIG. 3 is a graph showing battery voltage and current during a discharge and immediate recharge; and
FIG. 4 is a flow chart of the operation of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the system includes a regenerative energy source component 10 . This is a device that converts the kinetic energy usually wasted in the vehicle braking process into electrical energy. For example, it can be a separate electric generator driven by the wheels as they brake. It also may be the electric vehicle's or hybrid vehicle's electric motor that is operated as an electric generator that is activated when the vehicle brake pedal is pressed. The regenerative component 10 is suitably linked to a vehicle mechanical energy system, such as the brakes and/or wheels. Sensors (not shown) are provided to actuate component 10 when the vehicle braking occurs.
The electric energy (current) output from the regenerative component 10 is regulated to the desired voltage and current levels by a current-voltage controller 15 (hereafter CV controller). The CV controller 15 has the necessary components, such as capacitors, inductors and associated circuitry, to store some reasonable amount of energy temporarily and to regulate the output. The CV controller 15 receives the energy from the regenerative component 10 and supplies the current to recharge one or more batteries in a battery bank 20 located in the vehicle. The batteries in the bank can be of any suitable conventional type, such as lead-acid, and of any desired capacity, usually rated in amp hours. Each battery in the bank 20 has a number of cells and the batteries are connected in any suitable series parallel array to achieve a desired current and voltage output.
The functions of the CV controller 15 is controlled by commands sent from a micro-controller 25 . The micro-controller 25 is any suitable microprocessor type device that is programmable and has the necessary memory (ROM and RAM) and an arithmetic logic unit. It is preferred that the micro-controller 25 be programmable from an external source, such as by a serial bus. The micro-controller 25 also has the necessary circuits such as analog to digital and digital to analog converters. It receives analog data from the CV controller 15 and supplies operating command signal data back to operate CV controller 15 . The micro-controller 25 also receives data, such as the open circuit voltage and voltage during charging, from each battery in the battery bank 20 or the voltage of the total bank. It also receives data of the current drawn from or charged to the battery bank, such as measured across a shunt (not shown) and battery case temperature from a suitable sensor. The micro-controller 25 also stores control programs and algorithms.
The battery bank 20 is also connected through a motor load controller 30 to the vehicle's electric motor 35 , which uses the energy from the battery bank 20 as and when needed. The motor 35 also can be operated as a dual function device so that it also can serve as the regenerative component 10 .
The voltage and current going into the batteries of the battery bank 20 through the CV controller 15 and out through the motor load controller 30 is continuously monitored by the micro-controller 25 . The sensor output of various components 15 , 30 and 35 , the voltage of the individual batteries of the bank 20 and the entire battery bank 20 are monitored by the micro-controller.
From the data supplied to it, the micro-controller 25 can determine whether the batteries are being charged or discharged, and the amount of such charge or discharge and also the battery voltage output either during operation of electric motor 35 or under a no load condition. The micro-controller 25 stores algorithms and programs to calculate from the acquired data various factors such as battery internal resistance (impedance) and SOC. It can also track the acquired data against programmed algorithms to determine when certain conditions of the battery have been reached. This is explained below relative to FIGS. 2 and 3.
Responding to the command from the micro-controller 20 , the CV controller 15 outputs a regulated electric energy (amount of current) to charge the batteries in battery bank 20 , or other storage devices such as super capacitors, to store the energy.
There can be switches (not shown) to prevent the battery discharging into the CV controller 15 when the regenerative component 10 has no energy to supply to the battery between the battery bank 20 and the CV controller 15 operated and controlled by the micro-controller 25 . Alternately, the CV controller 15 may include remote controllable actuators to function as switches.
Charging of the batteries 20 is controlled in a manner to achieve a relatively high level of SOC, for example, about 80% and to recharge the batteries at a relatively high efficiency level. This is explained below.
FIG. 2 describes the behavior of a lead acid cell voltage and its impedance as a function of charge time when the cell is charged at a constant current. Similar curves exist for other types of storage batteries, such as nickel- cadmium and nickel metal hydride batteries. This relationship is described in greater detail in U.S. Pat. No. 4,745,349, which is assigned to the assignee of the subject application and is hereby incorporated in its entirety by reference.
FIG. 2 shows a single cell of a lead-acid battery having a voltage range of from 2.0 to 2.65 volts. If cells are connected in series, this would be a per cell value. The data for the curves of FIG. 2 corresponding to the size and type of battery 20 in the vehicle, are programmed into the micro-controller 25 so that it is available to be compared to the data acquired from the batteries of bank 20 as they are charged and discharged.
As seen in FIG. 2, as a constant current charge is applied to the battery cell over time, shown in minutes, the battery cell voltage V, shown by the solid line 42 , exhibits a sharp rise at the battery charge gas point C, in the cell voltage response, shown by the dotted line 44 . The increase in voltage occurs at the gas point C due to starting of a gas evolution reaction.
It should be understood that as the battery is being charged over time, that its SOC will increase, assuming that the battery is not defective. Thus, the value of voltage V and impedance A during battery charging is related to battery SOC. At any time after the gas point C, or when the battery voltage is higher than the voltage value of the rise at gas point C, the charge current is more than the cell can accept in the charge reaction. The excess current substantially only produces gas in the battery.
From FIG. 2 it can be seen on line 44 that the cell impedance A is high during the time starting from point C, when the gas evolution is initiated. In fact, the cell impedance A also exhibits a sharp rise somewhat prior to the rise in the cell voltage V. As shown, the impedance A starts to rise slowly when the battery voltage V is at the point O on line 42 and rapidly at the voltage point M. Early occurrence of the increase in cell impedance compared to the increase in cell voltage is due to adsorption of the gas on the surfaces of the cell plates.
As can be seen from FIG. 2, the battery gas point can be determined by measuring either or both of the battery impedance or its voltage during the charging. Both of these parameters can be measured and continually monitored by the micro-controller 25 .
The increase in cell impedance leads to an increase in cell temperature due to additional cell internal resistance (IR) heating. For this reason the charge current and charge voltage should be controlled so that no gas evolution reaction occurs during charging. From FIG. 2 it can be seen that the point M should be the upper voltage limit, so as to prevent gas evolution. This corresponds to 2.4 V/cell in a lead-acid battery. It is preferable to have the voltage limit at the point O which corresponds to 2.35 V/cell. That is, the charging voltage should not exceed 2.35 V/cell, meaning that the charge current from the regenerative system should be reduced or terminated corresponding to the point after about 150 minutes in FIG. 2 . By monitoring the battery voltage and keeping it below the value at which gas evolution occurs, the battery can be charged to higher SOC levels.
In industrial lead-acid batteries (thick plate construction), the point M occurs at around 80% state of charge. In automotive batteries (thin plate construction), the point M is closer to 90% state of charge. These values are higher than the 65% state of charge used in normal operation of the electric and hybrid vehicle batteries. By maximizing the charge current and quickening the charge time, the 80% or 90% SOC value can be reached.
In accordance with the invention, it is preferred that when the battery is recharged by the component 10 , that the magnitude of the charge current applied be as high as possible when charging starts, without exceeding the safe limit of the vehicle wires and other components. To explain this, reference is made to FIG. 3 .
FIG. 3 shows the current I, line 46 , and voltage V, line 48 , behavior of a fully charged 12 volt automotive lead-acid battery during a simulated vehicle starting process. This is described in greater detail in U.S. Pat. No. 4,937,528 which also is assigned to the assignee of the invention and is hereby incorporated by reference. As seen, just prior to starting the battery has an OCV (open circuit voltage) of about 12.7 volts and battery current of 0 amps. At the time of starting there is a large current discharge from the battery, as shown on the graph vertical axis. This is caused by the current drawn to start the vehicle motor and other systems. The current discharge pulse is of about5 seconds duration and is followed by the recharge from a charging system, such as an alternator/regulator in the car. The recharge is shown for a period over about 175 seconds with a voltage limitation, as set by the alternator construction and various devices, such as Zener diodes, on line V of 14.1 V. This is equal to 2.35 V/cell and corresponds to the optimal point O in FIG. 2 .
Two important points should be noted in FIG. 3 . For the current 1 , line 46 , supplied to the battery, up until time point L the current intake by the battery is limited only by the current output limitation of the charging system. That is, the size of the alternator and its components and the vehicle wiring.
The voltage limitation of 14.1 V is reached at the point N on curve 48 , which occurs at about the 65 seconds time mark in FIG. 3 . At this time, the current charge intake corresponding to voltage point N is more than about 80% of the amount of the discharge pulse. Thus, from this pulse test it is clear that the battery is capable of being quickly recharged with more than 80% of the charge taken out during the immediately preceding discharge. This is true even when the battery's SOC was near 100% to start with, as shown in this case.
In general, the higher the charge current immediately after the discharge pulse, the better the charge efficiency within the voltage constraints of 2.35 V/cell. That is, the greater the magnitude of current that is supplied, the less time it will take for the battery to reach the desired 2.35 V/cell limit. Similarly, the faster the recharge, without placing the battery in an open circuit condition, the higher the charge efficiency. Referring to FIG. 2, above the voltage of 2.35 V/cell, the charge efficiency decreases due to the energy being used to generate gas in the battery and battery IR heating. As a result, the battery gets hot which is not good for its life.
In the present state of the art, electric and hybrid vehicle batteries are operated at around 60%-65% state of charge (SOC) under the belief that the impedance and charge efficiency are better around this value SOC. However, as explained above, I have found that this is true only if the battery is allowed to reach equilibrium. When the battery is in a dynamic situation, such as discharge caused by the electric motor load and recharge caused by dumping the regenerative energy immediately after removing the load, a significant percentage of the energy can be put back into the battery without evolving gas. The only important criteria are
(1) dump as much current as possible and as quickly as possible and
(2) to limit the voltage to 2.35 to 2.4 V/cell. Use of this voltage limitation makes it possible to reach around 80%-90% SOC. This limit voltage may be adjusted depending on the ambient temperature. In general, the lower the battery temperature, the higher the voltage limit.
Accordingly, the system of FIG. 1 operates in the following general manner. Referring to FIG. 4, the micro-controller 25 is programmed (S 1 ) to sense the termination of a battery discharge, either substantially continuous or of the pulse type, such as when use of the electric motor 35 is stopped, and vehicle braking occurs.
After such a termination of discharge, whether continuous or pulse type, the regenerative component 10 is driven (S 2 ) by the vehicle mechanical system to produce current that is supplied to the CV controller 15 . The micro-controller 25 controls the current output of the CV controller to battery bank 20 so as to satisfy two requirements. First, (S 3 ) the maximum amount of current is to be less than the safe value limit of the vehicle wiring and other components. Second, (S 4 ) the data of the battery voltage or the battery impedance is monitored during charging. This data is used to control the current charge (S 5 ) to occur only up until the time at or slightly before that at which the gas point occurs (see FIG. 2 ). When the gas point limit is reached, the battery charging is terminated by the micro-controller 25 , by either stopping the regenerative component 10 from producing an output (S 5 ), such as mechanically disengaging it from the braking system, or operating the CV controller 15 so as not to produce an output to the battery bank 20 . Also, (S 6 ) the rate of charging can be limited so that the 2.35V/cell value of FIG. 3 is not exceeded. Other voltage values would be used for different types of batteries.
The rate and the amount of regenerative energy dumped into the battery may also be controlled depending on the time elapsed between the discharge and the charge process at higher state of charge conditions. This control is primarily achieved by using voltage as an indicator. The dumping current is maintained such that the battery voltage does not increase more than a predetermined value, this being 2.35V/cell in a lead acid battery.
It is also preferred that the battery be periodically charged to its full charge either while on the vehicle or in the battery shop. This will desulfate the battery to the extent, large or small, that the sulfation has built up in the battery during the persistent undercharged operational condition of the battery.
Specific features of the invention are shown in one or more of the drawings for convenience only, as each feature may be combined with other features in accordance with the invention. Alternative embodiments will be recognized by those skilled in the art and are intended to be included within the scope of the claims. | A method and apparatus (FIG. 1 ) for optimizing recharging of batteries ( 20 ) in an electric or hybrid vehicle that uses an electric motor ( 35 ) powered by the batteries ( 20 ) and having a regenerative system ( 10 ) that uses mechanical forces of the vehicle to generate current to recharge the batteries. The output of the regenerative system is controlled ( 15 and 35 ) to supply a maximum amount of current to recharge the batteries immediately after termination of a pulse or continuous discharge thereby to recapture a larger portion of the discharge current (FIG. 3 ) and the battery voltage is monitored ( 35 ) during recharge and the voltage is controlled ( 15 ) during charge so that it does not exceed a predetermined value at which battery gas evolution takes place (FIG. 2 ), thereby permitting the battery to be charged to a relatively high state of charge. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid delivery device, a liquid chromatograph, and a method for operation of said liquid delivery device.
2. Description of the Related Art
Any liquid chromatograph is provided with a liquid delivery device, among which is that of reciprocating plunger type. A conventional one of that type usually has two cylinders in each of which a plunger reciprocates, so that it delivers a liquid continuously, with two cylinders repeating sucking and discharging alternately.
Liquid delivery in this manner takes a certain length of time until the cylinder pressure reaches the discharge pressure because the liquid is compressed when the liquid, which has been suck up into the cylinder, is forced out by the plunger. As soon as the liquid is pressurized and the cylinder pressure reaches the discharge pressure, the valve at the discharge side is opened to deliver the liquid.
The drawback of such operation lies in the difficulties of detecting that the cylinder pressure is equal to the discharge pressure and the error of detection that prevents accurate control. This drawback leads to pulsation of liquid delivery that occurs in synchronism with the frequency of plunger movements. Such pulsation causes errors in liquid chromatography as described in Patent Documents 1 and 2.
Patent Document 1: Japanese Patent No. 3491948
Patent Document 2: Japanese Patent No. 3709409
OBJECT AND SUMMARY OF THE INVENTION
The present invention was completed in view of the foregoing. It is an object of the present invention to provide a liquid delivery device, a liquid chromatograph, and a method for operation of said liquid delivery device.
The present invention is directed to an improved liquid delivery device having a plurality of cylinders, each with a reciprocating plunger, a motor to drive said plunger, a control unit to control operation of said motor, a discharge pressure detector to measure the discharge pressure of the eluent being discharged from said cylinders, and a cylinder pressure detector to measure the pressure of said eluent flowing in said cylinders, wherein said improvement is characterized in that said control unit establishes the judgment point before the pressure measured by said cylinder pressure detector agrees with the pressure measured by said discharge pressure detector and controls the speed of rotation of said motor on the basis of the discharge pressure measured by said discharge pressure detector and the pressure measured by said cylinder pressure detector.
The present invention is directed also to an improved liquid delivery device having cylinders arranged in series in more than one stage, plungers reciprocating in said cylinders arranged in more than one stage, a motor to drive said plungers, a control unit to control operation of said motor, a discharge pressure detector to control the discharge pressure of the eluent discharged from the cylinder in the last stage, and a cylinder pressure detector to measure the pressure of said eluent flowing in the cylinder in the initial or middle stage, wherein said improvement is characterized in that said control unit controls the speed of rotation of said motor on the basis of the discharge pressure measured by said discharge pressure detector and the pressure measured by said cylinder pressure detector.
The present invention is directed also to an improved liquid delivery device having a plurality of cylinders, each with a reciprocating plunger, a motor to drive said plunger, a control unit to control operation of said motor, a supply flow channel to supply the eluent from the supply source to said cylinder that functions as a supplier, an inlet check valve attached to said supply channel, an intermediate flow channel to lead said eluent, which has been pressurized in multiple stages including cylinders at said supply side, to said cylinder in the final stage, an outlet check valve attached to said intermediate flow channel, a discharge pressure detector to measure the discharge pressure of said eluent being discharged from said cylinder in the final stage, and a cylinder pressure detector to measure the pressure of said eluent flowing in said cylinders excluding said cylinder in the final stage, wherein said improvement is characterized in that said control unit establishes the judgment point before the pressure measured by the said cylinder pressure detector agrees with the pressure measured by said discharge pressure detector and controls the speed of rotation of said motor on the basis of the discharge pressure measured by said discharge pressure detector and the pressure measured by said cylinder pressure detector.
The present invention is directed also to an improved liquid delivery device having a first cylinder with a first reciprocating plunger and a second cylinder with a second reciprocating plunger, a motor to drive said first and second plungers, a control unit to control operation of said motor, a supply channel to feed an eluent from a supply source to the inlet of said first cylinder, an inlet check valve fitted to said supply channel, an intermediate flow channel to introduce said eluent discharged from the outlet of said first cylinder to the inlet of said second cylinder, an outlet check valve fitted to said intermediate flow channel, a discharge pressure detector to measure the discharge pressure of said eluent being discharged from said second cylinder, and a cylinder pressure detector to measure the pressure of said eluent flowing in said first cylinder, wherein said improvement is characterized in that said control unit establishes the judgment point before the pressure measured by said cylinder pressure detector agrees with the pressure measured by said discharge pressure detector and controls the speed of rotation of said motor on the basis of the discharge pressure measured by said discharge pressure detector and the pressure measured by said cylinder pressure detector.
The present invention is directed also to an improved method for operating a liquid delivery device having a first cylinder with a first reciprocating plunger and a second cylinder with a second reciprocating plunger, a motor to drive said first and second plungers, a control unit to control operation of said motor, a supply channel to feed an eluent from a supply source to the inlet of said first cylinder, an inlet check valve fitted to said supply channel, an intermediate flow channel to introduce said eluent discharged from the outlet of said first cylinder to the inlet of said second cylinder, an outlet check valve fitted to said intermediate flow channel, a discharge pressure detector to measure the discharge pressure of said eluent being discharged from said second cylinder, and a cylinder pressure detector to measure the pressure of said eluent flowing in said first cylinder, with the liquid delivery achieved by one reciprocating cycle of said first and second plungers being divided into three phases, wherein said improvement is characterized in that, in phase 1, said inlet check valve is opened and said outlet check valve is closed so that said eluent is sucked up by said first plunger and said eluent is discharged by said second plunger, phase 2 has the first half section for compression and the second half section for liquid delivery, in said compression section, said inlet check valve and said outlet check valve are closed and said eluent which has been sucked up into said first cylinder is compressed, during which said eluent is discharged by said second plunger, said eluent in said first cylinder is compressed by said first plunger 1 , as soon as the pressure (the pressure measured by said cylinder pressure detector) due to this compression reaches the discharge pressure (the pressure measured by said discharge pressure detector) of said second cylinder, said outlet check valve 10 is opened and said compression section shifts to said liquid delivery section, in said liquid delivery section, said first plunger and said second plunger together force out said eluent, in phase 3, said inlet check valve is closed and said outlet check valve is opened, said second plunger sucks up said eluent, said first plunger 1 discharges said eluent, this discharge is combined with the amount which is sucked up by said second plunger, and said motor is controlled in such a way that it runs fast in the compression section of phase 2 and it runs slow in the liquid delivery section of phase 2.
The present invention covers a liquid delivery device capable of delivering an eluent with a minimum fluctuation of pressure, a liquid chromatograph equipped with said liquid delivery device, and a method for operation of said liquid delivery device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a liquid chromatograph with the liquid delivery device according to Example 1 of the present invention.
FIG. 2 is a diagram showing how the check valves move and the flow rates change in response to the angle of cam rotation in Example 1 of the present invention.
FIG. 3 is a diagram showing the pressure change in the first cylinder that occurs in the compression section in Example 1 of the present invention.
FIG. 4 a schematic diagram showing the liquid delivery device according to Example 2 of the present invention.
FIG. 5 is a diagram demonstrating the effect produced by Example 1 of the present invention.
FIG. 6 is a flow sheet showing the steps from the start of operation in compression section R (with the motor running at twice the normal speed) to the end of operation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The examples of the present invention will be described below with reference to the accompanying drawings.
Example 1
The liquid chromatograph equipped with the liquid delivery device will be outlined below with reference to FIG. 1 .
The liquid chromatograph shown in FIG. 1 consists of a liquid delivery device 300 , a sample injector 400 , a column 500 , a detector 600 , and a waste storage 700 .
The liquid delivery device 300 has a first cylinder 2 holding therein a first plunger 1 and a second cylinder 4 holding therein a second plunger 3 . The plungers are made to reciprocate respectively by a first cam 5 and a second cam 6 .
These cams are driven by a motor 7 , which is under control by a control unit 8 . The first cylinder 2 has an inlet and an outlet which are provided respectively with an inlet check valve 9 and an outlet check valve 10 . Thus, it sucks up an eluent 11 through the sucking side of the inlet check valve.
The first cylinder 2 has a cylinder pressure detector 12 to measure the pressure therein, and the second cylinder 4 has a discharge pressure detector 13 to measure the pressure of liquid being discharged. The rotational shaft has a disk 14 attached thereto, which has slits to facilitate detection of cam position by the cam position detecting sensor 15 .
A term “supply channel” is used herein to denote the channel through which the eluent 11 is supplied from the eluent reservoir to the inlet of the first cylinder 2 . The supply channel is provided with the inlet check valve 9 . A term “intermediate channel” is used herein to denote the channel through which the eluent discharged from the outlet of the first cylinder 2 is introduced to the inlet of the second cylinder 4 . The intermediate channel is provided with the outlet check valve 10 .
FIG. 2 shows the movement of each part which corresponds to the rotating angle of the cam.
That is, FIG. 2 shows timing at which the inlet check valve 9 and the outlet check valve 10 open and close within one cycle (or one reciprocating motion of the plunger). It also shows the amount of eluent to be sucked up and discharged by the first plunger 1 and the second plunger 3 and the total amount of liquid delivered by the liquid delivery device in one cycle. It also shows the speed of motor rotation in terms of the angle of cam rotation.
The delivery of the eluent in one cycle is divided into three phases. In phase 1, the first plunger 1 sucks up the eluent 11 , with the check valve 9 remaining open and the check valve 10 remaining closed. Also, in phase 1, the second plunger 3 only works to deliver the eluent at a constant flow rate Q.
Phase 2 is further divided into two sections—the first one for compression and the second one for liquid delivery. In the first section of phase 2, the inlet check valve 9 and the outlet check valve 10 are closed, so that the eluent 11 sucked up into the first cylinder 3 is compressed. In this period, only the second plunger 3 discharges the eluent at a prescribed flow rate.
The eluent in the first cylinder is compressed by the first plunger 1 until the pressure in the cylinder reaches the discharge pressure. At a desired pressure, the outlet check valve 10 opens and the second section of phase 2 starts for liquid delivery. In the section for liquid delivery, the eluent is forced out by the first plunger 1 and the second plunger 2 .
In phase 3, the inlet check valve 9 remains closed and the outlet check valve 10 remains open. The second plunger 3 moves in such a direction as to suck up the eluent. The first plunger 1 discharges the eluent such that the amount of discharge is the sum of the prescribed amount of pump delivery Q and the amount sucked up by the second plunger.
The compression section R in phase 2 is varied in length according to the discharging pressure of the liquid delivery device. Thus, the liquid delivery device discharges the compressible eluent at a constant flow rate. The compression section R is extended or shortened in proportion to the pressure of the liquid being delivered.
There is a relation as explained below between the compression section R and the flow rate Q (which is the amount of the eluent that is delivered in a unit time). In the compression section R, the outlet check valve 10 is closed, only the second plunger 3 delivers the eluent at a flow rate Q, and the first plunger 1 compresses the eluent which has been sucked up. In this way it is possible to deliver the compressible liquid at a constant flow rate regardless of its degree of compression. This technique is disclosed in Japanese Patent No. 3709409.
According to the disclosed technique, each cam is so curved as to deliver the eluent at Q/2 (or half the prescribed flow rate Q) and the motor 10 is run at twice the normal speed N in the compression section. In this process, the second plunger 3 delivers the eluent at a flow rate Q and the first plunger 1 compresses the eluent. As soon as the compression section R is completed, the rotational speed of the motor 7 returns from 2N to N (normal speed).
In the liquid delivery section of phase 2 and also in phase 3, the outlet check valve 10 remains open. Therefore, in these periods, the first cylinder 2 and the second cylinder 4 have the same pressure. While this state exists, the first pressure detector 12 and the second pressure detector 13 are checked for their calibration.
Problems with this liquid delivery device are errors produced by the two pressure detectors.
Errors are unavoidable in any pressure detectors. They arise from noise in signals, fluctuation due to change in environment (such as ambient temperature), and change with time. They also vary depending on the type of eluent.
For example, if the value indicated by the cylinder pressure detector is lower than the actual one (in which case the pressure in the first cylinder 2 has reached the discharge pressure of the second cylinder 4 ), the system judges that further compression is necessary and causes the motor to run at twice the normal speed.
In this state, the outlet check valve remains open and both the pressure detectors receive the same pressure. However, the cylinder pressure detector 12 always reads a smaller value than the outlet pressure detector 13 , which results in the motor continuing to run at twice the normal speed.
One way of avoiding this trouble in the conventional system was by returning the rotational speed of the motor 7 to normal speed N assuming that the two pressures have reached the same value before the difference between the reading of the outlet pressure detector and the reading of the cylinder pressure detector 12 actually becomes zero. Changing the motor speed in this manner decreases pressure and causes pulsation.
According to the present invention, the foregoing problem is addressed by establishing a point of judgment before the reading of the cylinder pressure detector agrees with the reading of the discharge pressure detector (which is lower than the reading of the discharge pressure detector), thereby calculating the point at which compression is completed. Controlling in this way prevents pressure fluctuation. The history of compression helps calculate the point of completion of compression which permits adequate control.
FIG. 3 is a graph showing the change in pressure that occurs in the first cylinder during compression.
In this graph, the abscissa represents the angle of rotation of the cam and the ordinate represents the change of pressure in the first cylinder. As soon as the sucking of the eluent is complete, the compression cycle starts. The starting point of the compression cycle is determined as the cam position detector 15 senses the cam angle. As mentioned above, the motor 12 runs twice the normal speed in the compression cycle.
First, the rate of change in pressure (denoted by K) is obtained after a certain length of period required for the system to stabilize, which is measured from the point at which the motor starts to run at twice the normal speed in the compression cycle. The value of K, which represents the slope of pressure increase in the first cylinder 2 , is calculated from the pressure increase (Pd) corresponding to the predetermined step value (Ss) which is measured by the cylinder pressure detector 12 . Incidentally, the motor 7 is a step motor whose angle of rotation depends on the number of pulses.
Next, the extended period (or step value), denoted by Sa, is obtained from Sa=Ss/Pd·Pa. Then, compression is continued, with the motor running at twice the normal speed, until the judgment pressure (Pe=Pout−Pa) holds. Additional compression in this manner is carried out for a period corresponding to Sa. After that, the delivery of eluent is continued, with the motor running at the predetermined normal speed.
The number of steps (Sa), which corresponds to the extended period, equals that for Pa (the width of values established for pressure).
As soon as the judgment pressure (Pe) is reached, the motor is run for the number of steps (Sa), which corresponds to Pa (the width of values established for pressure) previously obtained from K (the rate of change in pressure), and the compression section R in phase 2 (with the motor running twice the normal speed) terminates. Operation in this manner eliminates pulsation which results from the motor running at twice the normal speed and the pressure decreasing in the conventional technology.
FIG. 3 shows the behavior of water, alcohol, and acetonitrile as the eluent. They vary in K (the rate of change in pressure) according as they vary in compressibility. This problem is addressed by operation in the foregoing manner which terminates the compression section R (with the motor running twice the normal speed) which is calculated from K (the rate of change in pressure) for individual species of eluent. In this way it is possible to eliminate pulsation which results from the motor running at twice the normal speed and the pressure decreasing.
Incidentally, the motor 7 is a step motor as mentioned above. The high speed rotation (at twice the normal speed) and the low speed rotation are controlled by the cam position detecting sensor 15 . Control in this manner is accomplished accurately because the step motor turns through any angle in response to the number of pulses. Therefore, the step motor permits accurately controlled rotation.
The motor 7 is controlled by the program stored in the control unit 8 .
FIG. 6 is a flow chart showing steps from the start of the compression section R (with the motor running at twice the normal speed) to the end of operation.
In Step S 101 , the discharge pressure detector reads the discharge pressure (Pout) of the second cylinder. In Step S 102 , the judgment pressure (Pe) is calculated from Pe=Pout−Pa (where Pa is the width of pressure values which may be established arbitrarily).
The judgment pressure (Pe) is lower than the discharge pressure (Pout), and it occurs before compression is completed in the compression section (R) of phase 2.
In Step S 103 , the rate of change in pressure (K) in the first cylinder is measured and calculated from the initial part of phase 2 (K=Ss/Pd). K varies depending of the species, temperature, and aging of the eluent. The pressure of the first cylinder should be measured after it has become stable, so that the rate of change in pressure (K) can be measured more adequately.
In Step S 104 , the point of completion of compression is calculated (Sa=K·Pa). In Step S 105 , the system confirms that the pressure of the first cylinder has reached the judgment pressure. In Step S 106 , the motor continues to rotate for a period equivalent to the extended section (Sa minutes) from the judgment point, and the compression section R (for the motor running twice the normal speed) terminates. The foregoing steps are repeated.
The steps starting from the compression section R to the termination of operation are implemented according to programs stored in memory in the control unit 8 .
Example 2
FIG. 4 shows another example of the present invention.
This example demonstrates the so-called “high-pressure gradient” system, which is so designed as to deliver a mixture of solvents whose mixing ratio varies gradually. The gradient system according to this example is comprised of two units of the liquid delivery device described in Example 1. It has one pressure detector to measure the discharge pressure and control two pumps.
An ordinary high-pressure gradient system hardly produces a stable flow rate on account of two pumps interfering with each other. This interference occurs when the pressure detector to control the flow rate of one pump is affected by pressure fluctuation arising from the action of the other pump, and it disturbs control. This is not the case with the present invention in which the read value of discharge pressure is not used for control and hence no interference occurs. Thus the high-pressure gradient system according to the present invention is able to deliver a mixture of solvents in a stable mixing ratio at a stable flow rate.
FIGS. 5( a ) and 5 ( b ) show respectively the effect produced without or with control according to the present invention. The former suffers periodic pressure decrease, whereas the latter is free of periodic disturbance. | The present invention provides a liquid delivery device for liquid chromatographs which, by performing liquid delivery at an accurate flow rate with limited pulsation, gives accurate results of analyses. The present invention, with a view to preventing erroneous operation due to errors in measurements at the time of judgment of completion of compression of liquid, establishes the judgment point before the pressure measured by a cylinder pressure detector agrees with the pressure measured by a discharge pressure detector and also calculates the point of completion of compression. Control in this manner prevents pressure fluctuation. It also calculates for control the point of completion of compression from the history of compression performed previously. | 8 |
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates to a positron emission tomography device, and more specifically, to a positron emission tomography device using a γ-ray detector comprising a very fast (of the order of nanoseconds or less) scintillator.
PRIOR ART
[0002] Positron emission tomography (henceforth “PET”), is a tomographic method used for nuclear medical diagnosis wherein a subject is given a radioactive drug (tracer) labeled by a positron radiator, the radiation emitted outside the body is measured, and the concentration distribution of the drug is measured as a tomogram. (“Medical Imaging Handbook” (1994); RADIOISOTOPES, 42, 189-198; (1993) RADIOISOTOPES, 42, 237-254); (1993) RADIOISOTOPES, 42, 301-314; (1993) RADIOISOTOPES, 42, 365-376 (1993).
[0003] The positrons emitted from the tracer (atomic nucleus) travel several millimeters inside the body, lose kinetic energy, collide with nearby electrons and disappear. At this time, γ-rays (511 keV) having an energy equivalent to the electronic mass are emitted in the 180° direction. By detecting these γ-rays with a detector, processing the signal and performing image reconstruction, a tomogram of the distribution of the positron emission tracer in the body is obtained.
[0004] This detector usually comprises a scintillator, a photomultiplier and the necessary electronic circuitry. It is preferred that this scintillator uses a crystal scintillation having a fast response, using crystals such as NaI(Tl), BGO (Bi 4 Ge 3 O 12 ), CsF, BaF 2 , LSO (Lu 2 (SiO 4 )O:Ce). Of these, the γ-ray detection efficiency of BGO is high and it is therefore often used, but it has the fault that the damping time is as slow as about 300 ns. The damping time of NaI (Tl) is also of the same order.
[0005] If the response time of the scintillator used as PET detector is slow, and the signal from the detector has a fairly large width over time, the disappearance position of the tracer cannot be determined within this width. With the newest PET devices, the spatial resolving power is increasing, but complex computational processing is required.
[0006] Time-of-flight type PET aims to improve the PET image by measuring the time lag during which γ-rays travel inside the body by an external detector (RADIOISOTOPES, 42, and 301-314 (1993)). Specifically, if two detectors detect the γ-rays emitted in the 180 direction, the difference of their arrival times is equivalent to the flight time of light moving through a distance which is twice the difference of tracer positions, so the tracer position can be measured. In this field, a resolution of 1 cm or less is ideally required, which corresponds to a scintillator having a response speed of about 10 −10 seconds (0.1 ns). For this reason, BaF 2 crystals with a fast response are used, but their response speed (resolution) is only approx. 300-400 ps, and a faster scintillator was desired (“Medical Image Handbook”, Shinohara (1994)).
[0007] On the other hand, the Inventor already discovered that the radiation resistance of the exciton luminescence of a specific perovskite organic/inorganic hybrid compound is high, and that if this compound is used as a radiation scintillator, it emits visible light with a very fast response (Japanese Unexamined Patent Application No. 2001-006132, Japanese Unexamined Patent Application No. 2001-231205). It was shown that such a perovskite type organic/inorganic hybrid compound can be used for detection and dosimetry of ultrashort pulse ionizing radiation.
[0008] Problems to be solved by the invention
[0009] As the response speed of the scintillator used in the prior art positron emission tomography device was extremely limited, there was also a limit to the resolution of the positron emission tomography device. To resolve this problem, it was understood that the scintillator should have a response speed of approx. 10 −10 seconds (0.1 ns). If such a scintillator can be manufactured, a time-of-flight PET can be realized.
[0010] Means to solve the Problems
[0011] The Inventors already discovered that when a specific perovskite organic/inorganic hybrid compound is used as a radiation scintillator, it emits light with a very fast response.
[0012] It was discovered that by using this scintillator as a γ-ray detector of a positron emission tomography device, the problems inherent in the positron emission tomography device of the related art could be solved.
[0013] Specifically, this invention is a positron emission tomography device comprising a γ-ray detector consisting of a scintillator and a light-receiving device, wherein said scintillator is a perovskite organic/inorganic hybrid compound selected from the group represented by the general formulae:
[0014] (R 1 —NR 11 3 ) 2 MX 4 or (R 2 —NR 12 ) 2 MX 4 , (NR 13 3 —R 3 —NR 13 3 )MX 4 or (NR 14 2 ═R 4 ═NR 14 2 )MX 4 , or AMX 3 . In addition to a γ-ray detector, the positron emission tomography device of this invention may also comprise electronic circuitry for processing the signal from the γ-ray detector, and a computer which performs image reconstruction and other tasks.
[0015] R 1 is a monovalent hydrocarbon group, which may be a straight chain, branched or cyclic, preferably having 2-18 carbon atoms preferably an alkyl group, aryl group or aralkyl group, more preferably an alkyl group. The aryl group is preferably phenyl. The aralkyl group is preferably (C 6 H 5 )C n H 2n (n=2˜4). R 1 may also include a heterocyclic ring such as pyrrole or thiophene. R 11 is hydrogen or an alkyl group having two or fewer carbon atoms, preferably hydrogen or methyl, more preferably hydrogen, and may be the same as or different from each other such group in the organic/inorganic hybrid compound.
[0016] R 2 is a divalent hydrocarbon group which may contain a heterocyclic ring, may be substituted by a halogen atom and may be cyclic. R 12 is hydrogen or an alkyl group having two or fewer carbon atoms, preferably hydrogen or methyl, more preferably hydrogen, and may be the same as or different from each other such group in the organic/inorganic hybrid compound.
[0017] R 3 is a divalent hydrocarbon group which may contain a heterocyclic ring and may be substituted by a halogen atom. Examples of divalent hydrocarbon groups are straight chain or branched, but preferably straight chain, alkyl groups preferably having 2-18 carbon atoms. These may further contain a phenylene group (—C 6 H 4 —), preferably p-phenylene, a propyl group, or a heterocyclic ring such as thiophene. R 3 may comprise only heterocyclic rings. An example of the perovskite organic/inorganic hybrid compound when it contains a thiophene group, is the compound having the following structural formula:
[0018] (wherein, m represents an integer in the range of 2-8).
[0019] R 13 is hydrogen or an alkyl group having two or fewer carbon atoms, preferably hydrogen or methyl, more preferably hydrogen, and may be the same as or different from each other such group in the organic/inorganic hybrid compound.
[0020] R 4 is a tetravalent hydrocarbon group which may contain a heterocyclic ring, may be substituted by a halogen atom and may be cyclic. An example of the perovskite organic/inorganic hybrid compound when R 4 is cyclic, is the compound having the following structural formula:
[0021] R 14 is hydrogen or an alkyl group having two or fewer carbon atoms, preferably hydrogen or methyl, more preferably hydrogen, and may be the same as or different from each other such group in the organic/inorganic hybrid compound.
[0022] If R 1 -R 4 contain unsaturated bonds such as double bonds or triple bonds, high energy radiation is absorbed causing radical reactions, which is undesirable. However, the perovskite organic/inorganic hybrid compound may be formed by using a precursor containing double bonds or triple bonds, and then eliminating these unsaturated bonds by crosslinking them, by irradiating with high energy radiation. In this case, by crosslinking the organic layer comprising these hydrocarbon groups, crystal imperfections due to heating, etc., decrease, and the performance can be stabilized when the compound is used as a scintillator.
[0023] A represents R 5 —NH 3 , R 6 ═NH 2 or a mixture thereof, R 5 represents a methyl group or hydrogen which may be substituted by an amino group or halogen atom, and R 6 represents a methylene group which may be substituted by an amino group or halogen atom.
[0024] An example of the perovskite organic/inorganic hybrid compound where this A part is a mixture, is (CH 3 NH 3 ) (1-x) (NH 2 CH═NH 2 ) x PbBr 3 (0<x<1).
[0025] As A, a moiety of small volume, such as [CH 3 NH 3 ] + or [NH 4 ] + , is used.
[0026] As the volume of these moities (R 5 —NH 3 ) or (R 6 ═NH 2 ) is small, the inorganic layers are not separated by an organic material, so a three-dimensional network of an inorganic substance is formed, and the organic substance enters the interstices between regular octahedronal clusters of the metal halide. Herein, the conditions for (R 5 —NH 3 ) or (R 6 ═NH 2 ) are that they are monovalent cations of a size which can be occluded in the interstices of the three-dimensional compound.
[0027] Specifically, R 5 is a methyl group or hydrogen, and this methyl group may be substituted by an amino group or halogen atom. R 6 represents a methylene group, and this methylene group may be substituted by an amino group or halogen atom.
[0028] Examples of (R 5 —NH 3 ) or (R 6 ═NH 2 ) are H—NH 3 , CH 3 —NH 3 and NH 2 CH═NH 2 (formamidinium cation). It is preferred that this scintillator is a single crystal, but it is not necessarily a single crystal and may be a polycrystal coated on a substrate.
[0029] X is a halogen atom, preferably Cl, Br or I. X may also be a mixture of these halogens.
[0030] M is a Group IVa metal, Eu, Cd, Cu, Fe, MN or Pd, preferably a Group IVa metal or Eu, more preferably a Group IVa metal, still more preferably Ge, Sn or Pb, and most preferably, Pb.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] [0031]FIG. 1 shows the typical construction of a positron emission tomography device.
[0032] In the figure, 1 is a detector, 2 is a data acquisition unit, 3 is an image information control unit, 4 is a calculation processing unit, 5 is a dosage control unit, 6 is a dosage unit and 7 is a display unit.
[0033] [0033]FIG. 2 shows the time profile of the scintillation of (CH 3 NH 3 )PbBr 3 .
[0034] [0034]FIG. 3 shows the time profile of the scintillation of (C 6 H 13 NH 3 ) 2 PbI 4 .
DETAILED DESCRIPTION OF THE INVENTION
[0035] Hereafter, this invention will be further described by examples, but these are not to be construed as limiting the invention in any way.
[0036] A positron emission tomography device comprises a γ-ray detector, an electronic circuit which processes this signal, and a computer which performs image reconstruction and other tasks. An example of this device is shown in FIG. 1.
[0037] This device comprises a detector 1 , a data acquisition unit 2 , an image information control unit 3 , a calculation processing unit 4 , a dosage control unit 5 , a dosage unit 6 and a display unit 7 . The detector 1 is arranged in a circle so that a large number of γ-ray detectors surround the measured part of a subject (or analyte). Each detector is connected by coincidence circuits to plural detectors in the opposite position on the circumference.
[0038] These γ-ray detectors are assigned an address so that they can identify a spatial position, and their light-receiving surface is oriented in the direction of the measured part.
[0039] A γ-ray is emitted in the 180° direction from the measured part by a positron emitted from the tracer, and detected by the γ-ray detector facing this γ-ray.
[0040] Each β-ray detector is connected to the data acquisition part 2 , and the detected signal is transmitted from the γ-ray detector to the data acquisition part 2 . The data acquisition part 2 records the pair of detectors in the large number of γ-ray detectors forming the detector 1 which detected the γ-ray, on each occasion that there is a coincidence count. This data is stored in the data acquisition part 2 , and is sent to the image information control part 3 according to a preset image pick-up frame. The image information control part 3 has prestored image information, and sends the image information to the calculation processing part 4 according to the image pick-up frame. The dosage unit 6 has a means (for example, an intravenous injection syringe) for administering the tracer to the subject (or analyte), and the tracer is thereby suitably administered to the subject (or analyte) under the control of the dosage control unit 5 . Based on the data sent from the data acquisition part 2 and the image information control part 3 , the calculation processing part 4 calculates the tracer dosage conditions required by the measured part of the subject (or analyte), transmits them to the dosage control unit 5 , and thereby controls the dosage conditions of the dosage unit 6 .
[0041] The display unit 7 displays the γ-ray concentration or a computed tomogram sent from the calculation processing part 4 .
[0042] The γ-ray detector comprises a scintillator for γ-rays, light-receiving device, and other required electrical circuits.
[0043] There is no particular limitation on the light-receiving device, but as the scintillator of this invention emits light in the visible light range (about 400-600 nm), it is preferred to use a photomultiplier for visible light as the light-receiving device. The precise luminescence wavelength varies with the structure of the perovskite organic/inorganic hybrid compound, so it is preferred to use a photomultiplier suitably adjusted for this.
[0044] The construction of the γ-ray detector can be suitably modified for PET.
[0045] Examples are a construction wherein the scintillator is in contact with the light-receiving surface of the photomultiplier, a construction wherein the scintillator and photomultiplier are connected by a light waveguide, a construction wherein the light emitted by the scintillator is received by a photomultiplier separated from the scintillator, or a construction wherein the light emitted by the scintillator is received by a light-receiving port separated from the scintillator, and this light-receiving port and photomultiplier are connected by a light waveguide. The signal of the light-receiving device is processed by the usual method.
[0046] The resolution of the PET device depends on the width of the scintillator, which is preferably as small as possible. If the photomultiplier is made small on the other hand, there is a problem that performance falls. Therefore, the construction of the γ-ray detector is usually that of the individual connection type wherein the scintillator and photomultiplier correspond to each other 1:1, or the coding type wherein a large number of scintillators are connected with a small number of photomultipliers (RADIOISOTOPES, 42, 237-254 (1993)). These constructions may be used for the PET of this invention, or other constructions may be used.
[0047] A ring having a partition may be interposed between a scintillator and a photomultiplier to reduce noise. Such a γ-ray detector may be combined as appropriate with known techniques in this field (RADIOISOTOPES, 42, and 237-254(1993)).
[0048] As the scintillator of this invention has a response speed of subnanosecond order or less, it may be used as a γ-ray detector of a time-of-flight PET. The construction of this PET device is identical to that of an ordinary PET device, and the electronic circuit which processes the signal of the γ-ray detector is constructed so that, by measuring the time lag of the signal from two γ-ray detectors, the spatial position of the tracer can be reconstructed.
[0049] The scintillator is the above-mentioned perovskite organic/inorganic hybrid compound.
[0050] A comparison of the performance of these compounds with existing scintillators is shown in Table 1. From this table, it is seen that the perovskite organic/inorganic hybrid compound of this invention has a short decay time constant compared with other existing scintillators, and that the estimated response speed including the rising of the signal is very near about 0.1 ns, which is currently required for PET.
TABLE 1 Scintillator NaI (T1) BGO BaF 2 LSO Compound A Compound B Atomic No. 53, 11 83, 32, 8 56, 9 71, 58, 14, 8 82, 35, 7, 6, 1 82, 53, 7, 6, 1 Peak wave 410 480 220 420 550 525 length (nm) 300 440 Decay time 250 300 06 32 0.16 0.045 constant (ns) 620 54 Relative 100 15 6 38 not measured not measured luminescence 32
[0051] The compound A of Table 1 is (CH 3 NH 3 )PbBr 3 , and its decay time constant is shown in Measurement Example 1. The compound B of Table 1 is (C 6 H 13 NH 3 ) 2 PbI 4 , and its decay time constant is shown in Measurement Example 2. NaI(Tl), BGO, BaF 2 , LSO are reference values. For (C 6 H 13 NH 3 ) 2 PbI 4 in Measurement Example 2, measurements were carried out on a film, but if the same procedure as that of Measurement Example 1 is performed on this compound, crystals can be produced.
[0052] The amount of luminescence can be increased by cooling the scintillator of this invention by a suitable means.
[0053] As shown in the measurement examples, the decay time constant of the perovskite organic/inorganic hybrid compound of this invention shown in Table 1 was measured using an electron beam, but the physical and chemical processes induced in the irradiated substance are essentially identical for electron beam irradiation and γ-rays. It is therefore considered that the values for Compound A and Compound B in the table are identical to those obtained by irradiating with γ-rays.
[0054] As the PET device of this invention comprises a γ-ray detector comprising a scintillator having a very fast response (subnanosecond order or less) with respect to γ-rays, its image resolution is very high, and it can be used as a time-of-flight PET.
EXAMPLES 1
[0055] 60.22 g hydrobromic acid (HBr, Wako Pure Chemicals, concentration 0.48) was introduced in a 200 ml flask at room temperature, and 27.06 g of 40% aqueous methylamine solution (Wako Pure Chemicals, concentration 0.41) was gradually dripped in. As this is an exothermic reaction, the flask is placed in a water bath. Methylamine was dripped until the molar ratio of hydrobromic acid, HBr, to methylamine, CH3NH2 , was 1:1. After addition was complete, the mixture was left with stirring for 1 hour to complete the reaction, and a colorless, transparent aqueous solution of methylamine bromide was thus obtained.
[0056] When the water was removed on an evaporator (water bath temperature 45° C.), a white powder of methylamine bromide remained. This was washed by diethyl ether (suction filtration), and after removing unreacted material, it was dried. The yield was 35.98 g, i.e., 90.0%.
[0057] Next, 18.8 g of the methylamine bromide obtained as mentioned above was dissolved in 100 ml DMF in a 200 ml three-necked flask at room temperature, and 61.62 g lead bromide, PbBr 2 (Highly Pure Chemicals, purity 99.99%) was added a little at a time until the molar ratio of methylamine bromide and lead bromide, PbBr 2 , was 1:1. To avoid reaction between the moisture in the air in the three-necked flask, the mixture was left with stirring for 1 hour to complete the reaction while steadily passing a current of dry nitrogen through the flask, and a DMF solution (transparent and colorless) of the perovskite type compound, (CH 3 NH 3 )PbBr 3 , was thereby obtained. The solvent was evaporated on an evaporator (water bath temperature approx. 80° C.), and a microcrystalline powder of a red perovskite compound remained. This was washed by diethyl ether to remove unreacted material, and dried. The yield was 78.41 g, i.e., 97.5%.
[0058] The microcrystalline powder of the obtained perovskite compound was dissolved in as little of a good solvent (dehydrated DMF) as possible, and undissolved material was filtered off using a filter having a retention capacity of about 0.1 micrometers. This solution was introduced into a container (glass bottle A) for depositing crystals. Glass bottle A was subjected to ultrasonic cleaning with pure water beforehand. Next, a poor solvent (toluene, diethyl ether, nitromethane, etc.) was introduced into a glass bottle B. In order to dehydrate the poor solvent, a little calcium chloride powder was also introduced into glass bottle B. Glass bottle A and glass bottle B were stored in a desiccator, sealed off from the atmosphere, and left for four days at room temperature. At this time, the poor solvent which evaporated from glass bottle B spread into the perovskite compound solution in glass bottle A so that the solubility of the solution in glass bottle A gradually fell, and red, transparent single crystals of perovskite type compound deposited on the bottom of glass bottle A. Glass bottle A was shaded by wrapping the whole desiccator in aluminum foil. By this method, single crystals of approx. 2 cm×2 cm×1 cm can easily be produced.
[0059] When the obtained single crystals were excited using an electron beam pulse of 200 femtoseconds accelerated to 30 MeV by a linear accelerator (LINAC) in vacuo (approx. 10 −6 torr (1.33×10 −4 Pa)), a luminescence with a peak wavelength of 550 nm was observed. The time transition of luminescence intensity of this luminescence was measured using a streak camera (Hamamatsu Photonics, Inc., FESCA-200) with a resolving time of 260 femtoseconds as light receiving device. The result is shown in FIG. 2. As a result of this numerical analysis, the decay time constant of this luminescence was approx. 160 picoseconds.
EXAMPLE 2
[0060] A stratified perovskite compound (C 6 H 13 NH 3 ) 2 PbI 4 was synthesized by reacting lead iodide, PbI 2 , as metal halide, with C 6 H 13 NH 3 I as organoamine halide acid salt in a molar ratio of 1:2, in N,N-dimethylformamide (reaction temperature: room temperature (20° C.), reaction time: 1 hour or more).
[0061] 1 g of this stratified perovskite compound was dissolved in 3 ml of acetone, and spin-coated onto a silicone (Si) substrate of 2 cm side using a Shimadzu P/N 202-32016 (rotation speed: 5000 rpm, time: 30 seconds or more), so as to manufacture a scintillator (thickness of stratified perovskite compound, 0.1 micrometers). Herein, a silicon substrate is used to avoid luminescence from the substrate.
[0062] The radiation detector used in this measurement example comprises a cylindrical stainless steel pillar having a diameter of approx. 50 cm, and provided with a window on which the radiation is incident, light-receiving port, sample holder and pressure reducing device. This sample holder is a movable type wherein a sample (i.e., the scintillator) can be arranged effectively in the center of the pillar. The light-receiving port is connected with an external detector by a light waveguide, and measures and records the amount of light received. Examples of detectors used were a spectroscope (Acton Research Corporation, SpectraPro 150), grating (Acton Research Corporation, 150 gr/mm, Blaze 500 nm), and a CCD camera (Prinston Instruments, 330×1100 (8ch).
[0063] The scintillator (1 cm×1 cm×0.1 micrometers) manufactured as mentioned above was set in this sample holder so that the radiation incident on the surface of the stratified perovskite compound impinged perpendicularly. Subsequently, the pressure was decompressed to 1.0×10 −6 Torr using a combination of a rotary pump and turbo-molecular pump as decompression device. This scintillator was irradiated by hydrogen ions (protons) accelerated to 2 MeV at a flux of 3×10 11 ions sec −1 cm −2 (50 A) at room temperature (Nissin High Voltage Van der Graaf accelerator), and the irradiation time was varied to 5 seconds, 20 seconds and 180 seconds. From this scintillator, a strong exciton luminescence having a wavelength of 524 nm (visible region) was observed.
[0064] The time transition of luminescence intensity of this luminescence, observed by exciting the scintillator manufactured as described above using an electron beam pulse of 200 femtoseconds accelerated to 30 MeV(s) by a linear accelerator (LINAC) in vacuo (approx. 10 −6 torr), was measured by a streak camera with a resolving time of 260 femtoseconds as light-receiving device. The result is shown in FIG. 3.
[0065] As a result of this numerical analysis, the decay time constant of this luminescence was approx. 45 picoseconds. | As the response speed of the scintillator used in the prior art positron emission tomography device was extremely limited, there was a limit to the resolution of the positron emission tomography device. To resolve this problem, it was considered that the scintillator should have a response speed of approx. 10 −10 seconds ( 0.1 ns). If such a scintillator can be manufactured, a time-of-flight PET can be realized.
The inventor already discovered that if a specific perovskite organic/inorganic hybrid compound is used as a radiation scintillator, it emits visible light with a very fast (subnanosecond order) response, and that this scintillator can be used as the γ-ray detector of the positron emission tomography device. The PET device of this invention comprises as a scintillator a perovskite organic/inorganic hybrid compound selected from the group represented by the general formulae:
(R 1 —NR 11 3 ) 2 MX 4 or (R 2 —NR 12 ) 2 MX 4 , (NR 13 3 —R 3 —NR 13 3 )MX 4 or (NR 14 2 ═R 4 ═NR 14 2 )MX 4 , or AMX 3 . | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates to a sewing equipment apparatus ideal for sewing sheet material having an extremely vast area, and more particularly to sewing apparatus capable of performing a so-called relay sewing process for sewing together the side end parts of adjacent broad cloths overlapped together, simultaneously for a plurality of cloths laid in the lateral direction.
2. Prior Art:
A sewing machine capable of performing the so-called relay sewing process of sewing with each edge part of two broad cloths overlapped with each other without folding the cloths is disclosed in Japanese Patent No. 1,232,866. The sewing machine disclosed in this publication is constructed as shown in FIG. 9, that is, a base end part 502a of an arm 502 to be set up on a bed 501 is disposed at the nearer side (arrow F side) of a needle location P', and this base end part 502a of the arm 502 is formed so that the shape of the section orthogonally intersecting with the cloth feeding direction may be approximately in a Z-form. In the sewing machine thus constructed, when feeding the cloths to the needle location side, each cloth to be sewn can individually pass through the upper side and lower side of the orthogonal part with the cloth feeding direction in the base end part in the approximately Z-form, so that all cloths may be smoothly sewn without having to be folded back.
Conventionally, however, in such a relay sewing process, an operator is used to join the side ends of two fabrics and assists by forwarding the cloths into the needle location by hand along with the feeding operation of the sewing machine.
Recently, to be, the cloth products to be formed by such a relay sewing process tend to be larger in size as compared with the former ones, as represented, for example, by a large-sized bellows type tent. These large cloth products can no longer be manufactured efficiently by such a method of sewing every two cloths. It is expected that such a problem will be solved when three or more cloths are sewn in the relay sewing process, but in the conventional general sewing machines, that is, in the machines having the base end part of the arm coupled to the bed at the side of the needle location this base end part, however, is an obstacle, so that the job of plaiting down the cloth located at the base end side of the arm from the needle location is needed, and because of this it was actually not considered possible to perform a relay sewing process simultaneously on three or more cloths.
SUMMARY OF THE INVENTION
To solve the above problems, it is a primary object of this invention to provide sewing apparatus capable of producing extremely large cloth products efficiently by performing the relay sewing process of three or more cloths simultaneously, on the basis of the idea of carrying out the relay sewing process without plaiting down the cloths in the sewing machine disclosed in the above noted Japanese Patent No. 1,232,866.
It is another object of this invention to provide sewing apparatus capable of more efficient production by designing so that the cloth sent out from the material side may move automatically from the nearer side to the farther side of the sewing machine along with the sewing steps.
An important feature of the sewing apparatus of the invention lies in the structure comprising plural sewing machines having the base end part of the arm set up on the bed disposed at the nearer side of the needle location and formed so that the shape of the section orthogonal to the cloth feeding direction of this base end part may be approximately in a Z-form possessing a partition wall parallel to the bed upper surface. These sewing machines are arranged parallel in the lateral direction so that each cloth feeding direction may be parallel, and the base end parts of the adjacent sewing machines are coupled to the bed at the opposite right and left sides of each sewing machine regarding the line segment parallel to the cloth feeding direction passing through the needle location of each sewing machine.
In the thus constructed sewing apparatus, the adjacent sewing machines can sew, on both sides of a piece of cloth passing at the upper side or lower side of the partition wall of the both base end parts, cloths passing at the opposite side of the respective partition walls to this cloth in each sewing machine. At this time, the cloths at both sides are overlaid on the same surface of the central cloth. Therefore, according to the sewing apparatus of this invention, at least three cloths can be simultaneously processed by relay sewing, and the production efficiency is significantly enhanced. Besides, these three cloths are overlaid alternately up and down, they do not descend in one direction as seen from the front, so that a flat product may be obtained on the whole.
Another feature of the sewing apparatus of this invention is as follows: the sewing machines have their coupling parts of the bed and arm base end part disposed below the needle location forming plane of the bed, and an ascending slope from the front end of the coupling part to the needle location side is formed on the bed, and the upper surface of the crossing part with the cloth feeding direction in the approximately Z-form base end part is positioned on the plane nearly level with the needle location forming plane.
In such sewing apparatus, one cloth is fed into the needle location of each sewing machine along the slope, while the other cloth is fed along the plane nearly level with the needle location. Therefore, before the needle location, no processing is needed on both cloths, and the cloths can be directly laid over mutually before the needle location. In other words, broad cloths can be sewn without having to plait them down, and such overlaying of cloths in the sewing process can be done spontaneously along with the movement of the cloths by the cloth feeding operation. Therefore, without requiring any particular overlaying mechanism, a sewing apparatus with an extremely high job efficiency can be realized at a low cost.
A still different feature of the sewing apparatus of the invention is that the sewing machines are for double chain sewing. That is, in the rear part behind the base end part on the slope of each sewing machine, an opening is formed which is normally closed by the detachable cover and is open to expose the inside-of the bed when the cover is removed, and a looper which is disposed in the bed and is normally in a sewing state is designed to be tiltable to the opening side.
In this construction, by inserting a hand into the bed from the opening formed in the slope directed to the front side in the rear part behind the arm base end part, the looper thread can be connected to the looper tilted to the opening side. Therefore, although the arm base end part is located ahead of the needle location, the looper thread connection job to the looper can be done extremely easily, and job efficiency may be notably enhanced.
In a further different embodiment of the sewing apparatus of this invention, a device for feeding into the needle location of each sewing machine in a state of overlaying the side end parts of the adjacent cloths with a cloths wound up from the material roll is disposed at the nearer side in the cloth feeding direction of each sewing machine, while a forward feeding device for feeding the sewn cloths to the rear side is disposed at the rear side in the cloth feeding direction of each sewing machine.
In the sewing in such a manner, the adjacent side end parts of the cloths wound up from the material roll are automatically overlapped along with the feeding action by the sewing operation of each sewing machine, and the cloths are sent into the needle location in this state, and the overlapped portion is sewn. Therefore, very broad cloths can be automatically sewn without requiring manual labor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic front view of a sewing apparatus, according to the present invention,
FIG. 2 is a schematic side view which explains the cloth feeding mechanism,
FIG. 3 is a front view of a first sewing machine,
FIG. 4 is a perspective view of a portion of the sewing machine of FIG. 3 illustrating essential parts thereof,
FIG. 5 is a magnified sectional view of a portion of the sewing machine of FIG. 3 which explains the overlapped state of cloths in individual sewing machines,
FIG. 6 is a perspective view of a portion of the sewing machine of FIG. 3 illustrating an opening therein,
FIG. 7 is an explanatory illustration of a looper tilting mechanism located in the opening of FIG. 6,
FIG. 8 is an explanatory illustration of the product state after a relay sewing process by the sewing apparatus off the present invention, and
FIG. 9 is a schematic perspective view showing a prior art sewing machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, numerals 1 to 4 are first to fourth sewing machines comprising the sewing apparatus. These sewing machines 1 to 4 may be represented by the first sewing machine as explained in FIG. 3 and FIG. 4. In FIGS. 3 and 4, numeral 101 is a bed, and 102 is an arm integrally set up on this bed 101.
The upper surface of the bed 101 is composed of a horizontal plane 101a forming the rear side, and a sloped plane or slope 101b tilting downward toward the near side (arrow F side in FIG. 4) to form the front side of the needle location P of the sewing machine.
The base end part 102a of the arm 102 is formed so that the shape of the section orthogonally crossing with the cloth feeding direction is approximately in a Z-form as estimated from the single-dot chain line a 1 in FIG. 3. At the same time, this base end part 102a is located at the nearer side (arrow F side) by a specified distance from the needle location P, on an extension from the needle center line parallel to the cloth feeding direction passing the needle location P. In other words, since the base end part 102a is located at the near side by the specified distance from the needle location P, it is integrally connected to the bed 101 at-the left end of the slope 101b of the bed 101 located to the left side, avoiding the needle center line. The base end part 102a approximately in Z-form is provided with a partition wall 102ab corresponding to a parallel portion to the upper surface of the bed 101. This partition wall 102ab is formed so as to be orthogonal to the cloth feeding direction, so that its upper surface may be positioned on the same plane as the horizontal plane 101a of the bed 101. Since the base end part 102a of the arm 102 is constructed in this way, the first sewing machine 1 is furnished with a lower cloth passage 1b at the lower side of the partition wall 102ab, and an upper cloth passage 1a at the upper side of the partition wall 102ab.
As shown in FIG. 2, the front end of the arm 102 is extended above the needle location P, and an arm head 103 is located in this part. Then, as shown in FIG. 3, from the arm head part 103 to the needle location P side, a needle mounting part 104 for mounting a sewing needle (not shown) on the front end projects. In FIG. 3, what is fixed on the upper face of the arm head 103 is a bobbin box 106 for mounting needle thread bobbins 105.
In the horizontal plane 101a of the bed 101, a known throat plate 107 is set in the portion including the needle location P forming area as shown in FIG. 6. On the boundary of the horizontal plane 101a and slope 101b positioned at the rear side (arrow B side) behind the base end part 102a, an opening 108 the horizontal plane 101a side of which is trapezoidal and the slope 101b side is rectangular, is formed. As clear from FIG. 6, in the sewing machine used in the sewing equipment shown in the illustrate example, the opening 108 is in contact with the throat plate 107 at the horizontal plane 101a side. That is, the throat plate 107 is notched so that its front side may be trapezoidal. In this opening 108, a cover 109 which is level with the horizontal plane 101a and slope 101b in the mounted state is detachably inserted.
Numeral 110 denotes pressor feet for pressing down the cloths supplied on the throat plate 107, and they are attached to the front end of the rod (not shown) projecting from the arm head 103, and are designed to be moved up and down by operating the lever 111 disposed at the side of the arm head 103.
Beneath the throat plate 107, there are disposed plural loopers 153, which can be tilted to the front side, that is, to the lower side of the opening 108 by the mechanism disclosed in the Japanese Utility Model No. 1,627,126.
This looper tilting mechanism is described below with reference to FIG. 7.
The plural loopers 153 are mounted on a looper shaft 151, and this looper shaft 151 is rotatably inserted into bifurcated crank arms 154a, 154a of a crank mechanism 154. Between the bifurcated crank arms 154a, 154a, a cam body 157 to be fixed on the looper shaft 151 is disposed as shown also in FIG. 6. Between the bifurcated crank arms 154a, 154a, moreover, a columnar pin 158, which penetrates through in a rotatable state and an eccentric pin 159 disposed ahead of this pin 158, are provided. The eccentric pin 159 is rotatable between a locking position to be engaged with an engaging concave part 157b formed on the outer circumference of the cam body 157 in a pressed state, and an unlocking position departing from the outer circumference of the cam body 157. On this eccentric pin 159, a knob 159a projecting outwardly of one crank arm 154a is formed integrally, and by manipulating this knob 159b by a finger, the eccentric pin 159 is rotated between the locking position and the unlocking position. When the knob 159a is turned until the eccentric pin 159 is engaged with the engaging concave part 157b of the cam body 157 as indicated by solid line in FIG. 7, the cam body 157 is fixed at a specified position by the pin 158 and eccentric pin 159, so that the looper shaft 151 is locked at the sewing position. When the knob 159a is turned in the reverse direction until the eccentric pin 159 is departed from the outer circumference of the cam body 157 as indicated by the single-dot chain line in FIG. 6, the confinement by the eccentric pin 159 is released, and the cam 157 fixed on the looper shaft 151 is set free (unlocked), and the looper 153 affixed on the looper shaft 151 can turn forward as indicated by the single-dot chain line. A coil spring 160 provides an elastic force for deviating the eccentric pin 159 to the engaging concave part 157b of the cam body 157.
As compared with the thus constructed first sewing machine, the third sewing machine 3 is exactly identical with this first sewing machine 1.
On the other hand, the second sewing machine 2 and the fourth sewing machine 4, which are not illustrated in detail, are formed so that their base end parts may be symmetrical to the first and third sewing machines 1, 3 as seen from the front side. That is, as evident from FIG. 1, in the first and third sewing machines 1, 3, the base end part 102a is linked to the left side of the bed 101 relating to the needle location P as seen from the front side, and the front end of the arm 102 comprising the arm head part 103 is extended upward at the right side of the bed 101 across the needle location P. By contrast, in the second and fourth sewing machines 2, 4, the base end part 202a is coupled to the right side of the bed 201 of these sewing machines 2, 4 with respect to the needle location P', and the front end of the arm 202 is extended upward at the left side of the bed 201 across the needle location P'. However, unless otherwise specified, the parts of the third sewing machine 3 in FIG. 1 are identified with the same reference numbers as the first sewing machine, and the parts of the second and fourth sewing machines 2, 4 corresponding to the parts of the first sewing machine 1 are provided with the reference numbers by replacing the first digit from 1 to 2 of those of the first sewing machine.
As seen from FIG. 1, the first and fourth sewing machines 1 to 4 are arranged parallel in the lateral direction so that the respective cloth feeding directions may be parallel to each other. Also as evident from the description herein, the adjacent sewing machines, that is, the first sewing machine 1 and the second sewing machine 2, the second sewing machine 2 and the third sewing machine 3, and the third sewing machine 3 and fourth sewing machine 4 are arranged so that the respective base parts may be symmetrical to each other. Furthermore, the lower cloth paths 1a, 2a and the upper cloth paths 1b, 2b of the sewing machines 1 to 4 are arranged at the same height individually.
When the sewing machines are configured as described above, as shown in FIG. 1, a cloth C 1 taken from one material roll stand (not shown) can pass both the lower cloth path 1a of the first sewing machine 1 and the lower cloth path 2a of the second sewing machine. Likewise, a cloth C 2 taken from one material roll stand can pass through the upper cloth path 2a of the second sewing machine 2 and the upper cloth path 1b of the third sewing machine 3, and a cloth C 3 taken from one material roll stand can pass through the lower cloth path 1a of the third sewing machine 3 and the lower cloth path 2a of the fourth sewing machine 4. Therefore, a total of five cloths including the cloth C 0 passing through the upper cloth path 1b of the first sewing machine, and the cloth C 4 passing through the upper cloth path 2b of the fourth sewing machine 4 are simultaneously subjected to a relay sewing process in the vertically and alternatley overlaid state. Accordingly, the product after relay sewing process by the sewing apparatus in this way has the individual cloths C 0 to C 4 sewn up and down alternately at the side end parts as shown in FIG. 8.
In such a sewing apparatus, since it is not necessary to plait down the cloths taken into the sewing machines, as an example of which the first sewing machine 1 is shown in FIG. 2, the sewing process can be done automatically, by taking the cloths C 0 to C 4 from the material rolls R1, R2 by the take-out devices 5, 6, and delivering the clots to the sewing machine side, and by sending these cloths sewn by the sewing machines 1 to 4 further to the next process side by the forward feeding device 7 disposed behind the sewing machines.
In such a sewing apparatus, as shown in FIG. 5, since the upper surface of the partition wall 102ab composing the upper cloth path 1b is position in the same plane as the horizontal plane 101a of the bed 101, while the upper cloth path 1b converges with the lower cloth path 1a composed of the slope 101b of the bed 101 before the needle location P, the side end parts of the cloths C 0 , C 1 are mutually overlaid at the convergent point M of the cloth paths 1a, 1b and forwarded into the needle location P by the feeding operation accompanying the sewing motion. When the end parts overlaid in this way are sent into the needle location P, both cloths C 0 C 1 are sequentially subjected to a relay sewing process. In other words, according to this sewing apparatus, not only the trouble of plaiting down the cloths is avoided, but also any particular mechanism for overlaying is not needed although the cloths are fed from the different positions in the vertical direction. Therefore, by installing the feeding devices 5, 6 and forward feeding device 7 as mentioned above, the relay sewing process using a plurality of cloths can be done automatically.
Furthermore, with such a construction, for example, by removing the cover 109 positioned before the needle location P to open the opening 108 straddling the horizontal plane 101a and slope 101b of the bed 101, the crank arms 154a, 154a of the crank mechanism installed inside the bed 101 can be exposed from the opening 108. Since this opening 108 is formed in the slope 101b opposite the front side, the operator can easily put his hand into the bed 101 through this opening 108 from the front side, and can manipulate the knob 159a of the eccentric pin 159. Therefore, it is easy to cancel the engagement between the eccentric pin 159 and the engaging concave part 157b of the cam body 157. However, the mechanism for tilting the looper may not be necessarily as shown in FIG. 7, but the design may be modified in various manners.
When the looper 153 is tilted to the front side in this way, the looper 153 moves to below or near the corresponding part of the horizontal plane 101a of the opening 108, and by inserting a hand into the bed 101 from the opening 108, as in the case of manipulation of the knob 159a noted above, the looper thread may be easily connected to the looper 153. In this case, too, since the opening 108 is formed in the corresponding part of the slope 101b, the operator can easily put his hand into the bed 101 from the front side. Hence, in the sewing machines composing the sewing apparatus, the loop thread connecting work can be done in a spontaneous position beside the looper 153.
After the looper thread connection work, the knob 159a is operated again and the eccentric pin 159 is engaged with the engaging concave 157b of the cam body 157, and the cam body 157 is fixed by this eccentric pin 159 and pin 158, and hence the looper 153 is locked to a crank arms 154a, 154a, so that sewing operation is ready.
In a sewing machine for lock stitch not provided with loopers, the opening 108 is not needed. In this case, the cloths to be sewn can be overlaid without any particular mechanism, and the cloth is fed smoothly.
In this sewing apparatus, at least two sewing machines should be configured so that the coupling parts with the bed connected to the partition wall of the base end parts may be positioned opposedly at right and left sides of a line segment parallel to the cloth feeding direction passing through the needle location in each sewing machine. Each sewing machine may share the bed, or the bed of each sewing machine may be coupled by using other members. Furthermore, the numbers of sewing machines may be either equal or unequal. | Sewing apparatus, uses plural sewing machines aligned in a row so that the feeding direction of the cloths to be sewn is parallel, each sewing machine having a bed with an upper surface, an arm with a base end part formed coupled to the bed and a needle location. Each base end part having a shape, when viewed orthogonal to the cloth feeding direction, which approximates a Z-form possessing a partition wall the upper surface of which is parallel to the upper surface of the bed. The relay sewing process of sewing the side ends of adjacent broad cloths in an overlapped state can be performed simultaneously on plural cloths arranged in the lateral direction. | 3 |
BACKGROUND OF THE INVENTION
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/KR02/00921 which has an International filing date of May 16, 2002, which designated the United States of America.
TECHNICAL FIELD
The present invention is directed to a Rotary Engine as an internal combustion engine.
BACKGROUND ART
Ordinary rotary engines are designed to work four step strokes by providing a triangular rotor rotating eccentrically within a housing. To make such a housing and rotor is difficult due to their geometrical structure, and the rotary friction of the rotor is high during operation. Accordingly, the abrasion ratio of the rotor is high, and this is accompanied by many problems such as the production of smoke due to burning as a result of lubricating oil which is mixed with the fuel, as there is no independent lubricating function. Therefore, the rotary engine has not yet been actively utilized, even though it has many merits because it is small and light compared with the other types of reciprocating engines of the same power.
DISCLOSURE OF THE INVENTION
To solve the above problems according to the present invention, 4 strokes of the engine is performed by the piston operation, compressing and expanding the operation room by its sliding moving while the piston of the rotation body, which is rotating the axis of rotation in the cylinder type housing circumscribes with an oval guide part. This oval guide part is prominently formed from the housing toward the central part of the rotation body.
Also, in the piston of the rotation body, the shaft stick is connected to the guide bar which has a guide roller, and the guide roller is internally contacted with the oval guide surface of the housing. By this structure, every compression and/or expansion of the operation room in each strokes can be smoothly accomplished even with the operation of the centrifugal force.
During the process of the 4 strokes, the lubricating oil is introduced through the lubricating oil supply route and supply hole which are formed in the axis of rotation, and is removed through the discharge route and discharge hole to be circulated. Then the induction hole which intakes the fuel, the exhaust hole which discharges the exhausting gas, and the operation room are shut tight by an oil seal so that the flow of the lubricating oil into the operation room may be cut off during lubrication.
Consequently, according to the present invention, the composition is comparatively simple, and manufacturing is easy. The operation of the rotational body and the piston is supple and smoothly accomplished. Thus, vibrational noise and the abrasion ratio of the piston can be reduced and the smoke reduced due to its independent lubricating function.
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 become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is side cut view of the present invention;
FIG. 2 is detailed drawing of the present invention;
FIG. 3 is partial view of the exhaust hole utilized in the present invention;
FIG. 4 is structural drawing of the oil groove for the discharge of lubricating oil in the bottom of the rotational body, according to the present invention;
FIG. 5 is view of the piston used in the present invention;
FIG. 6 is plane view of the present invention; and
FIG. 7 is plane view which shows the working motion of the guide bar according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention, as shown in the FIG. 1 and 2, is composed of a cylinder type housing(A), a rotational body(C), an oval guide part(D), and a guide bar. In this construction, the rotational body(C), in which more than one(l) piston(B) is installed, is rotating around the axis of ration( 2 ) in the housing(A). An oval guide bar(D) is prominently formed at the internal surface of the housing(A) toward the central part of the rotation body(C). Also, the guide bar( 8 ) is formed at the shaft stick( 4 ) which is connected with the piston(B) and guided by the guide surface( 6 ) of the housing(A).
The induction hole( 10 ) for fuel introduction and the exhaust hole( 12 ) for gas exhausting are formed at the both sides of the housing (A). Between them, the ignition plug( 14 ) or the fuel supply device is alternatively installed by the particular engine(gasoline engine or diesel engine). The body( 16 ) in which an oval guide part(D) is prominently formed at the internal wall of the housing(A) and a lid( 18 ) which is connected by bolts with the body( 16 ) are provided in the internal space of the housing(A), and a shaft hole( 20 ) ( 22 ) through which an axis of rotation( 2 ) extends is formed at the guide part(D) and lid( 18 ) of the body( 16 ).
The body( 16 ) and lid( 18 ), which defines housing(A), forms cooling rooms( 24 ) ( 26 ) which are filled with cooling liquid. At the bottom of the body( 16 ), the cover( 30 ) which has the fuel inlet pipe( 28 ) is connected by bolts. In the cover( 30 ), the fuel pressure apparatus( 32 ) is set, and the fuel pressure apparatus( 32 ) in the turbine pattern is fixed on the axis of rotation( 2 ).
In the exhaust hole( 12 ), which is formed at the body( 16 ) of the housing(A), several inclined boards( 34 ) are set close together toward the turning direction of the rotation body(C) to increase the driving force when exhausting, as shown in FIG. 3 .
The oval guide part(D), prominently formed at the internal wall of the body( 16 ), has the shortest bottom point of the stroke and the longest peak point of the stroke from the central point of the shaft hole( 22 ), and is located in the center of the rotational body(C).
The operation space( 36 ) and oval guide surface( 6 ) are formed at the internal side of the lid( 18 ), and the operational space helps the free operation of the guide bar( 8 ), and the oval guide surface is engraved at the operation room. The oval guide surface ( 6 ) maintains an elliptical orbit in which the piston(B) can keep the circumscribed position with the guide part(D) through the inscribed guide bar( 8 ).
The rotational body(C) is composed of the cylinder shaped body( 38 ) and the airtight board( 40 ) ( 42 ) which are joined by bolts at both sides of the body( 38 ), and the axis of rotation( 2 ) is formed in one body with one of the airtight boards( 40 ).
More than one operation room( 44 ) is formed in the body( 38 ) of the rotation body(C), and in each operational room, an air hole( 46 ) is formed, which intakes the fuel and exhausts the gas after combustion. The air hole( 46 ) carries out the function of the operation room( 44 ) as a part of the operation room( 44 ) as well as intakes fuel and exhausts gas.
At the outer surface of the other airtight board( 42 ) of the rotation body(C) as shown in FIG. 4, many of the guide prominences( 48 ) are radially formed, which in turn form the oil route( 50 ), which promotes exhausting of lubricating oil.
The piston(B) is installed in each operation room( 44 ) of the rotation body(C) as shown in FIG. 5, and is constructed of a round head( 52 ), and body( 54 ) which is formed as a curve from one side of the head( 52 ) toward the inner side. This piston(B) is connected to the rotational body(C) with the shaft stick( 4 ) through the connecting hole( 56 ) of the head( 52 ), and the tail( 58 ) of the edge of body( 38 ) and the front( 59 ) are circumscribed to the oval guide part(D).
It is desirable to install the guide roller( 60 ) at the tail( 58 ) of the above piston(B) and the peak point of stroke(D- 2 ) to decrease friction when rotating.
The shaft hole( 4 ) which connects the piston(B) is formed in monolithic organization with the piston(B) through the connecting hole( 56 ) from outside of the airtight board( 40 ) in one side of the rotation body(C), and the guide bar( 8 ) is also formed in monolithic structure with the edge of the shaft hole( 4 ) outwardly exposed. The edge of the guide bar( 8 ) forms guide roller( 60 ) ( 62 ) and is contacted internally with the guide surface( 6 ) of the housing(A) through the guide roller( 62 ).
The axis of rotation( 2 ) is formed in monolithic structure at the other side of the airtight board( 40 ) of the rotation body(C), and is provided with lubricating oil supply route( 64 ) and lubricating oil discharge route( 66 ) at its inside. The lubricating oil supply route( 64 ) is connected with the inner part of the engine by the supply holes( 64 a ) and the lubricating oil discharge route( 66 ) is connected with the inner part of the engine by the discharge holes( 66 a ).
Oil seal( 68 ) is formed between the housing(A) and the rotation body(C), and between the rotation body(C) and piston(B), respectively. The oil seal( 68 ) prevents lubricating oil from flowing into the operating room( 44 ), the air hole( 46 ), the induction hole( 10 ), and the exhaust hole( 12 ).
The ignition plug( 14 ) of the present invention is located at the ignition point when the piston(B) passes by the peak point of stroke(D- 2 ) of the guide part(D). If a fuel supply device is installed at the ignition point instead of the ignition plug( 14 ), this is satisfactory for diesel engine.
The piston(B) contracts and expands the volume of operation room( 44 ) when passing by the bottom point of stroke(D- 1 ) and the peak point of stroke(D- 2 ) of the oval guide part(D) because the tail( 58 ) circumscribes the guide part(D) and the guide roller( 62 ) of the guide bar( 8 ), which is set up at the shaft stick( 4 ), inscribes the guide surface( 6 ) of the housing(A) when the rotation body(C) rotates.
At this time, the tail( 58 ) of the piston(B) begins to rotate toward the center of the rotation body(C) around the shaft stick( 4 ) by moving to the bottom point of stroke(D- 1 ) passing by the peak point of stroke(D- 2 ) of the guide part(D) from the time that the air hole( 46 ) of the operation room( 44 ) meets the induction hole( 10 ). According to the above rotation, the operation room( 44 ) contracts to the minimum size and then is expanded, more and more. The fuel, which flows into the fuel inflow pipe( 28 ) by injection at the maximum expansion of the operation room( 44 ), is strongly induced into the operation room( 44 ) throughout the induction hole( 10 ), as pressurized by the fuel pressure apparatus( 32 ).
This kind of induction operation continues while the air hole( 46 ) of the operation room( 44 ) passes by the induction hole( 10 ) of the housing(A). In this stroke, even though the centrifugal force occurs to the piston(B) by the rotation of rotation body(C), the strokes are normally performed because the guide bar( 8 ), which is connected to the shaft stick( 4 ), inscribes the oval guide surface( 6 ) of the housing(A) through the guide roller( 62 ).
The piston(B) circumscribes with the guide part(D), and by sliding motion contracts and/or expands the operation room( 44 ). The tail( 58 ) cannot maintain sliding contact with the guide part(D), especially in the inhaling course with no affect of the out force because there is a regular centrifugal force due to the rotation of the rotation body(C).
But, as shown in the FIG. 7, the tail( 58 ) of the piston(B) always circumscribes the guide part(D) without any affect of the centrifugal force because the tail( 58 ) of the piston(B) always circumscribes the guide part(D) and the guide bar( 8 ) inscribes the guide surface( 6 ) of the housing(A) through the guide roller( 62 ).
After the air hole( 46 ) of the rotation body(C) passes by the induction hole( 10 ) of the housing(A), the operation room( 44 ) and air hole( 46 ) are hermetically closed by oil seals( 68 ) which surround the inner surface of the housing(A), the operation room( 44 ), and the air hole( 46 ).
Thus, an induction stroke is completed.
When the induction stroke is completed, the tail( 58 ) of the piston(B) moves to the peak point of stroke(D- 2 ) passing by the bottom point of stroke(D- 1 ) of the guide part(D), and so, the minimized operation room( 44 ) at the bottom point of stroke is contracted, step-by-step to compress the fuel.
If the tail( 58 ) of the piston(B) reaches the peak point of the stroke, the volume of the operation room( 44 ) is minimized and the fuel is maximally compressed, and the compression stroke is completed.
When the ignition plug( 14 ) is fired at maximum compression, the fuel is burned to begin the expansion stroke. As the expansion force pulls the back of the piston(B), the rotation body(C) receives rotation power to rotate in the opposite direction of the clock hand.
At this time, the tail( 58 ) of the piston(B) moves to the bottom point of stroke(D- 1 ), passing by the peak point of stroke(D- 2 ), and the operation room( 44 ) is gradually expanded. By the continuation of the rotation, when the air hole( 46 ) of the operation room( 44 ) meets the exhaust hole( 12 ), the expansion stroke is completed and exhaust stroke is begun.
When the exhaust stroke begins, the tail( 58 ) of the piston(B) again moves to the peak point of stroke(D- 2 ) passing by the bottom point of stroke(D- 1 ), and accordingly the minimized operation room( 44 ) gradually contracts and the exhaust stroke rapidly proceeds.
In the exhaust stroke, many slanted boards are formed in the exhaust hole( 12 ) as shown in FIG. 3, and the driving force is added by the operation of the slant boards( 34 ).
When the air hole( 46 ) of the operation room( 44 ) completely passes by the exhaust hole( 12 ), the exhaust stroke is completed. At this time, the tail( 58 ) of the piston(B) again moves to the bottom point of stroke(D- 1 ) passing by the peak point of stroke(D- 2 ), and the minimized operation room( 44 ) is gradually expanded passing by the induction hole( 10 ), and the induction stroke which draws in the fuel again begins to repeat its stroke.
During these 4 step strokes, the lubricating oil, which is supplied through the lubricating oil supply route( 64 ) of the axis of rotation( 2 ), is induced between the housing(A) and rotation body(C), between the rotation body(C) and piston(B), and between the axis of rotation( 2 ) and housing(A) and/or the guide part(D), evenly distributed through the supply holes( 64 a ) to enable a smooth rotation. Thus, the circulating operation of the lubricating oil, in which the lubricating oil is exhausted through the supply hole( 66 a ) lubricating oil discharge route( 66 ), is performed.
There is no worry about generation of smoke caused by the combustion of the lubricating oil because the induction hole( 10 ), exhaust hole( 12 ), operation room( 44 ), and air hole( 46 ) are hermetically closed by oil seal( 68 ) to prevent the inflow of lubricating oil thereinto.
When the lubricating oil is exhausted, the lubricating oil rapidly moves to the central part through the oil route( 50 ) in the gabs of the radial guide prominences( 48 ) by the rotation of the rotation body(C), and the lubricating operation is smoothly performed.
According to the present invention, 4 strokes are performed by the piston(B) of the rotation body(C) by circumscribing with the guide part(D) and by slidably moving in the housing(A). Therefore, the present invention is very effective in easy of manufacturing due to a comparatively simple composition, smooth and tender operation with less rotation friction, less noise, a low abrasion ratio of the piston(B), and no concern about smoke generation from the lubricating oil due to the independent lubricating function, compared with the ordinary rotary engines in which the 4 strokes are performed by the eccentric rotation of the triangle rotor.
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 rotary engine including a cylinder shaped housing, a rotation body rotating in the housing, an oval guide part located at the center of the rotation body being prominently formed from the cylinder shaped housing. A axis of rotation being formed in monolithic structure with the rotation body penetrated through the cylinder shaped housing and the oval guide part, an induction hole, an exhaust hole, and an ignition plug or a fuel supply device in selection up to the engines. At least one of operation rooms being furnished with air hole and located in the rotation body, and each of pistons being at one side of the operation rooms to be rotated, wherein a tail and a front of said pistons circumscribe with the oval guide part and a guide bar inscribing with a guide surface of the cylinder shaped housing through a guide roller at a shaft stick connecting said pistons. | 5 |
TECHNICAL FIELD OF THE INVENTION
This invention relates to three point hitches for attaching agricultural and industrial implements to vehicles, and especially to pick up trucks. Three point hitches are commonly found on tractors for the connection to and operation of implements such as plows, mowers, and tillers.
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT STATEMENT
This invention was not developed in conjunction with any Federally sponsored contract.
MICROFICHE APPENDIX
Not applicable.
BACKGROUND OF THE INVENTION
Three point hitches are well-known within the art for providing a method of interconnect and control between a vehicle, such as a tractor, and an implement, such as a plow, mower, or tiller. Three point hitches typically provide manual or automatic control of the level of the implement and the depth of the implement through a system of extendable arms and lifting mechanisms. A hitch such as this for a tractor was disclosed in U.S. Pat. No. 3,572,763, to Cannon, et al. The Cannon patent describes a variety of three point hitches which provide the ability to extend the two lower draft arms and to controllably extend the upper link of the hitch, thereby allowing ease of interconnect of the hitch to an implement, and providing lift and height control of the implement. This functionality is common among three point hitches found on tractors.
Another common function found on tractor-borne three point hitches is a power takeoff, or "PTO", which is a form of mechanical transmission that provides a power linkage between the tractor's engine and the implement. The PTO allows the implement to receive power for its operation, such as turning blades on a mower.
However, tractors are somewhat specialized vehicles and are not well suited for use on public roadways. If a farm implement dealer needs to deliver a new or repaired implement to a rural farm, it cannot be attached to a tractor and driven down a roadway conveniently. Also, if an empty field is to be mowed and the field is located in a suburban environment, a tractor with mower implement must be stored on a trailer and driven to and from the field using a pulling vehicle, such as a truck.
There are known within the art some very light duty "class zero" three point hitches available for various brands of four-wheel motorcycles. Because of the light weight of "four wheelers" and the relatively small engine output of these vehicles, they are not suitable for use of the larger, heavier duty class I, II, and III farm implements.
To solve one particular need for a three point hitch, the apparatus disclosed in U.S. Pat. No. 4,940,096 to Johnson, et al, provides a three point hitch mounted on a common pick up truck. The Johnson hitch system does provide some lift control, but does not provide a PTO means. Further, the Johnson hitch system requires permanent or semi-permanent modifications to the pick up truck in order to provide the stable mechanical mount to the vehicle, which further limits its use as it cannot be stored in a barn and quickly attached to any available pick up truck.
A more flexible system for mounting a variety of utility implements to the bed of a pick up is disclosed in U.S. Pat. No. 3,883,020 to Dehn. The Dehn system is especially well suited for bed-mounted implements, such as towing cranes or wrecker rigs, and dump beds. While the Dehn system provides quick and easy installation on a truck, it does not provide a three point hitch and is not suitable for adaption to a three point hitch.
Therefore, there exists a need in the art for a system and method for mounting a three point hitch to a pick up truck quickly and easily. The mounting apparatus should not require modifications to the standard pick up truck hardware, and should not require permanent or semi-permanent installation of the hitch system.
Further, there exists a need in the art for this three point hitch system to allow installation and removal of the hitch to and from the pick up truck by a single human operator.
Finally, there exists a need in the art for the three point hitch system to provide a power takeoff so that the hitch is useful with powered implements such as mowers.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a three point hitch system which mounts temporarily and easily to a common pick up truck, without the need for modifications to the truck. The hitch system disclosed herein utilizes two common pick up truck mounting points, a square hitch receiver mounted on the truck frame just below the rear bumper, and a goose neck hitch mounted in the center of the truck bed above the rear axle of the truck.
Another object of the invention is to allow the hitch to be conveniently stored without the need for a special stand or holding frame, and to be installed and removed to and from a truck by a single operator. This will allow the hitch to be stored in a barn or shed while not in use, and then to be installed quickly to any available pickup truck, used for job, and then returned to the barn. This enables a farmer to own a few hitch systems, and to use them at will on a larger number of common pick up trucks, making the hitch system much more available and convenient than the sharing of a single or low number of utility tractors. It also allows pick up trucks to be used to transport farm implements over urban and suburban roadways using a pick up, for such tasks as delivery of new and repaired units to a rural farm.
Yet another object of the invention is to provide a power source and a power takeoff ("PTO") on the hitch system to allow powered implements, such as a mower, to be driven by the hitch system. This allows an operator to perform some operations using a pick up truck instead of a tractor, such as mowing a field. For example, combining the objects and features of the invention, a single pick up truck could be used to transport a mower over urban streets to an empty field, mow the field using the truck and hitch system as the power and propulsion vehicle, and returning the mower to a storage place without the need for a tractor or trailer, and saving the time of loading and unloading the tractor on the trailer.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the invention,
FIG. 1 shows a side view of the entire three point hitch system for pick up trucks, including its mounting points to the truck's gooseneck hitch and square receiver.
FIG. 2 shows the hitch system in a raised position and
FIG. 3 shows the system in its free-standing mode on its tripod stand.
FIG. 4 provides a view of the hitch system from the rear of the vehicle, which allows a better view of the power takeoff belt system.
FIG. 5 discloses a top view of the hitch system.
FIG. 6 shows the underlying frame of the hitch system, and
FIG. 7 shows a partial assembly view of the frame as viewed from the front of the system.
FIG. 8 is a schematic diagram of the drive train between the engine and the power takeoff.
FIG. 9 shows an alternate mechanism for attaching the hitch system to the square hitch receiver on the truck.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the objects of the invention set forth in the Summary of the Invention, the three point hitch system (1) shown in FIG. 1 mounts to a typical pick up truck which is equipped with a gooseneck hitch (4) on the bed (2) of the truck, and the truck's square hitch receiver (7) mounted under the truck's rear bumper (6). The gooseneck hitch is preferably located slightly towards the front of the truck from a vertical axis (5) of alignment with the truck's rear wheel (3) axle, which distributes the weight of the hitch and implement forward of the rear axle. The entire truck and hitch system is suitable for use on a variety of terrains (90) such as pavement and inimproved earth.
Because the height from the gooseneck hitch to the square receiver depends on the particular model of pick up and model of the gooseneck hitch, the frame of the hitch system is provided with a vertical height adjustment in the vertical frame members which mount to the gooseneck hitch. The front vertical support assembly (8, 9, 10), which attaches over the gooseneck hitch (4), has an upper section (8) and a lower section (9) of approximately equal diameter and constructed of hollow steel tubes. A center slidable section (10) of slightly less diameter than the upper and lower sections fits inside the upper and lower sections, and may be retained by a number of temporary fastening means, such as bolts with wing nuts and/or cotter pins. The rear vertical support (13) has a square receiver insert (15) which slides into the truck's square hitch receiver tube (7), such as a 2-inch Class III or Class IV hitch receiver, and it is also fastened using a temporary fastening means (16) such as a hitch pin or bolt with a wing nut.
A frame spine (12) extends from the front vertical support (8, 9, 10) to the rear vertical support (13, 14, 15). At the front of the spine (12) is a length adjuster (11). The forward end of the length adjuster (11) is attached to the upper section (8) of the front vertical support, and slidably inserts into the spine (12), as shown in FIG. 1. The spine (12) is secured to the rear vertical support by a set of mounting ears and an attachment hitch pin (71). The mounting ears are described in further detail in the discussion of FIGS. 6 and 7 below. A hitch frame is suspended from the spine (12) and provides the mechanical framework on which the components of the three point hitch interconnect. The hitch frame is shown in more detail in FIGS. 6 and 7.
The three point hitch subsystem consists of the usual components necessary to attach the hitch to an implement, including two lower draft arms (17) which provide two of the three points of the hitch at the rear ends of the arms (18). A lifting means (21) is provided in order to control the height and depth of the implement. In the preferred embodiment, this is a hydraulic cylinder lift, powered by a battery (26) and electric motor and hydraulic pump (25), all mounted on the hitch spine (12) and controllable by the operator. In the preferred embodiment, the lifting means (21) is securely mounted on one end to the hitch frame, and on the other end to a set of lift members (23 and 24), which allow for the expansion and contraction of the hydraulic cylinder to be converted to lift force on the draft arms (17). An upper link support (20) is located on the hitch frame at a point suitable for the upper link connection (19), thereby providing the third point of the three point mechanism. The upper link support (20) may require some vertical reinforcement, such as the diagonal reinforcement member (22) shown in FIG. 1, depending on the gauge of steel stock used for constructing the frame and support members.
In order to provide power to certain types of implements, the preferred embodiment of the three point hitch system provides a motorized power takeoff ("PTO"). This is a refined embodiment of the system, and may not be required for all applications of the system. The PTO subsystem consists of a motor (34) mounted on the system frame using motor mounts (36) to allow for vibration of the motor during operation. In the preferred embodiment, this is a 25 horsepower internal combustion engine, commonly available in the art, and it is provided with local or remote operator controls. The motor output shaft is equipped with a clutch device (35), which in turn drives an upper belt pulley (32). Preferably, the clutch device is an electromechanical clutch which engages the upper belt pulley (32) under switch control by the operator. Other embodiments such as a centrifugal clutch, which engages when the motor speed reaches a certain rotational speed, or a mechanical clutch, could be used.
A drive train is provided to transfer the motor's rotational energy from the motor's output shaft to the PTO. Pulley ratios used in the drive train reduce the motor's 3600 RPM output to an approximate 540 RPM at the PTO. FIG. 8 shows the drive train in detail, with an upper pulley (32) located directly on the output of the clutch (35). The lower belt pulley, located on the PTO drive shaft (30) is supported by a PTO support (31) which is affixed to the hitch frame. The drive train is preferably comprised of two belts, linked by a speed-reducing mid-pulley, shown in FIGS. 4 and 8, which are described infra. An alternate embodiment would use a hydraulic pump driven by the motor, with the hydraulic pressure from the pump being conducted from the pump's output to a hydraulic motor. The hydraulic motor would be located on the PTO shaft.
The mounting and stand subsystem is also a refinement in the preferred embodiment, and may not be necessary for cost reduced embodiments or embodiments intended for semi-permanent mounting of the hitch system to a vehicle. The system is provided with a tripod stand system. The rear two points of the tripod consist of two lowerable feet (52) under control of a hand crank (50), similar to the front stand feet commonly found on tractor trailer trucks. An operator can rotate the hand crank (50) using a handle (51) to lower or raise the two feet (52), which causes a lower section of each leg (53) to retract into or telescope out of the upper sections (54) of each leg. This type of stand and hand crank are well known in the art. The third point of the tripod stand is a front leg (44) located near the front of the spine (12) as shown in FIG. 1. The front leg (44) slides vertically in a holder (42), and has a front leg wheel (43) at the lower end of it. When the hitch is to be removed from a truck, attachment hitch pin (71) is removed disconnecting the rear vertical support (13) from the retention ears of the spine (12). Then, the rear two feet (52) are lowered to the ground and rear end of the spine (12) is raised such that it is not resting on the rear vertical support (13). The front end of the spine (12) is then raised by operating the front jack (72), which lowers the front jack wheel (40) to the truck bed (2), causing the lower section (9) of the front vertical support be raised above and clear the gooseneck hitch (4). The truck can then be driven forward, with the front of the hitch system being supported by the front jack wheel (40) rolling on the truck bed (2), and the rear of the hitch system being supported by the rear two feet (52) on the ground (90). As the truck continues to move forward and out from under the hitch system, the front leg (44) will drop from the bumper (6) of the truck until its wheel (43) contacts the ground. The front leg holder (42) is provided with a latch which secures the leg from sliding back upwards through the holder, so that the front leg (44) will provide support for the front of the hitch system as the truck completely clears the hitch and the front jack wheel (40) is no longer in contact with the truck bed (2).
FIG. 2 shows the hitch system with the lower draft arms (17) in a raised position, caused by the extension of the lift means (21), and FIG. 3 shows the system in its free-standing mode with all three legs of the tripod stand lowered and the truck or vehicle removed.
FIG. 4 provides a view of the lift system from the rear of the vehicle. Of particular interest in this view is the disclosure of the drive train, which consists of an upper belt pulley, and upper belt (33) to a mid-pulley (60), down through a lower belt to a pulley on the PTO shaft (30). The PTO shaft is supported by pillow blocks as shown. FIG. 8, described infra, shows a schematic of the drive train. The hidden attachment point to the square hitch receiver (14) is shown for reference. Also visible in FIG. 4 is the third point (19) on the three point hitch, which is located in the center of the coupling tube (70). The coupling tube (70), preferably constructed of 21/4 inch steel tube stock, provides interconnect between the two lift arms such that they raise and lower the draft arms together. The coupling tube (70) couples the left force from the side of the assembly equipped with the lift means to the side of the assembly without the lift means.
FIG. 5 shows the top view of the hitch system mounted to a truck bed (2) and the gooseneck hitch (4) and bumper (6). The relationship of the front jack (72) and front jack wheel (40) can be seen in this view. Also given in FIG. 5 is the preferred method of reinforcing the lift system by using two diagonal members towards the rear of the system, extending from the spine (12) to the outer sides of the hitch frame.
Turning now to FIG. 6, a simplified view of the underlying frame of the hitch system is shown. A hitch frame (82) is fabricated preferably of L-shaped angle iron welded to provide a square frame. Holes in the frame, such as the lower hole (80) and the upper hole (81), provide a point for a bolt or pin to secure the end of the draft arm and hydraulic lift cylinder. The spine (12) is preferably constructed from a length of square tubular steel stock, and welded to the top side of the hitch frame (82). Two slotted mounting ears (73) extend downward from the spine (12) near the interconnect of the spine (12) with the hitch frame (82). FIG. 7, a cut-away view of the simplified underlying frame is given from the front of the hitch system, it can be seen that the mounting ears (73) form an inverted saddle in which the upper end of the rear vertical support (13) rests. A pin (72) passes through the ears and holes in either side of the rear vertical support to hold the assembly together, and the pin is secured by a clip (83).
Finally, FIG. 8 shows a schematic of the power train, in which an upper pulley (32) drives an upper belt (33), and in turn drives a mid-pulley (60). The mid-pulley drives a smaller mid-pulley (90) through a mid-shaft (61). A lower belt (91) is driven by the smaller mid-pulley (90), and transfers power to the lower pulley (92), which is located on the PTO shaft.
FIG. 9 shows an alternate embodiment of the rear vertical support. In this embodiment, the square hitch receiver insert (15) is welded to a piece of angle iron stock to create a frame bottom support (150). The bottom side of the frame (82) rests on the frame bottom support (150), and is retained by pins (151) and cotter clips (152). Gussets (154) are preferably placed from the spine (12) to the frame (82) to provide additional structural support.
While the invention has been set forth in this disclosure with respect to the preferred embodiment, and in some cases optional embodiments have been set forth, it will be appreciated by those in the art that there are many ways to implement the structural design of the three point hitch system without departing from the spirit and scope of the invention and disclosure herein. | The three point hitch mounting system allows a pick up truck to be fitted with a three point hitch so that the pick up truck can be used to transport and operate common agricultural and industrial implements such as mowers, plows, and tillers. In enhanced embodiments, the mounting system provides for a stand that allows the hitch to stand freely when not mounted on a truck, a lift device to allow control of the depth and height of the implement, and a power source and power takeoff ("PTO") for driving powered implements, such as a mower. | 1 |
RELATED APPLICATION
[0001] This is a divisional application of U.S. application Ser. No. 10/995,037, filed Nov. 23, 2005.
FIELD OF THE INVENTION
[0002] This invention relates to novel benzofuran-2-yl-carbonyl- and indol-2-yl-carbonyl-trans-2,5-dimethyl-piperazine derivatives, their pharmaceutically acceptable salts, pharmaceutical compositions containing them and their use in therapy.
[0003] Another aspect of the invention is a method of treating inflammatory, autoimmune, proliferative and hyperproliferative diseases. A preferred method is the method of treating rheumatoid arthritis, atherosclerosis, systemic sclerosis, multiple sclerosis, Alzheimer's disease, encephalomyelitis, systemic lupus erythematosus, Guillian-Barre syndrome, allograft rejection, urticaria, angioderma, allergic conjunctivitis, atopic dermatitis, allergic contact dermatitis, drug or insect sting allergy, systemic anaphylaxis, proctitis, inflammatory bowel disease or asthma.
BACKGROUND
[0004] Chemokines are small secreted cytokines consisting of 8-14 kDa proteins, which can be classified into four groups according to the sequence of their conserved cysteine residues, CXC, CC, C and CX 3 C. They promote upregulation of cellular adhesion molecule, which enforces adhesion and lead to cell migration.
[0005] Hence, the chemotactic cytokines play a crucial part in the recruitment and trafficking of leukocyte subsets.
[0006] Among the CC chemokines, MIP-1α and RANTES, known as ligands for CCR1, CCR3, CCR4 and CCR5 receptors, are involved in autoimmune diseases such as rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis. This is strongly supported by the fact that CCR1 knockout mice show a significantly reduced incidence of disease in a mouse EAE model compared with the wild type mice. Studies by Karpus et al. (J. Immunol. 1995, 155, 5003) further prove the pivotal role of MIP-1α in the same model of multiple sclerosis. It was shown that antibodies to MIP-1α prevented the development of both acute and relapsing paralytic disease as well as infiltration of mononuclear cells into the CNS.
[0007] In addition, there is strong evidence implicating RANTES in the pathophysiology of rheumatoid arthritis. For example, RANTES mRNA was detected in synovial tissue samples from patients with rheumatoid arthritis (Snowden, N. et al., Lancet, 1994, 343, 547). Further, antibodies to RANTES greatly reduced the development of disease in an adjuvant-induced arthritis model in the rat.
[0008] A number of studies have provided evidence for a role of CCR1 in allograft rejection. Combining a sub-nephrotoxic amount of cyclosporin A with blockade of chemokine receptors using a CCR1 antagonist has been shown to have a positive effect on solid allograft survival (Horuk, R. et al., J. Biol. Chem. 2001, 276, 4199).
[0009] Therefore, molecules that inhibit the interaction between the inflammatory chemokines and their receptor would be beneficial in the treatment of inflammatory, autoimmune, proliferative and hyperproliferative diseases.
[0000] Related Disclosures
[0010] The International Patent Application WO 0164676 claims (cis)-4-(4-fluorobenzyl)-1-(7-methoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine as p38 kinase inhibitor.
[0011] The document is directed to compounds that are useful in treating inflammation and cardiac conditions. More particularly, the document concerns compounds to treat proinflammatory and heart and kidney conditions. No other specific benzofurans are claimed or exemplified.
[0012] The U.S. Pat. No. 5,814,644 discloses one indol-2-carbonyl derivative as synthetic building block for the preparation of dopamine antagonists, which are of benefit in the treatment of psychotic disorders.
[0013] The U.S. Pat. Nos. 4,115,569 and 4,374,990 claim derivatives of piperazine containing substituents of benzofuran as psychotherapeutic drugs.
DESCRIPTION OF THE INVENTION
[0014] It has now surprisingly been found that compounds of general formula (I)
wherein:
X is a fluorine or a chlorine atom;
the methyl groups located at the 2- and 5-position of the piperazine ring are in trans-configuration to each other;
Y is NH or O;
R 1 is selected from hydrogen, chloro, bromo, nitro, methyl or trifluoromethyl;
R 2 is selected from hydrogen, halo, methyl, trifluoromethyl, methoxy or trifluoromethoxy;
or a pharmaceutically acceptable salt or solvate thereof;
are unexpectedly effective in inhibiting the signalling of the chemokine receptor CCR1.
[0015] Of the compounds of the formula (I) as defined above, a preferred group of compounds of formula (I) is that group of compounds wherein:
[0000] X is a fluorine atom;
[0000] Y is NH or O;
[0000] R 1 is selected from hydrogen, chloro or bromo;
[0000] R 2 is selected from hydrogen, chloro, bromo, methyl, trifluoromethyl, methoxy or trifluoromethoxy.
[0000] Among the preferred compounds are:
[0000]
(trans)-1-(5-Bromo-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-4-(4-Chlorobenzyl)-1-(5-chloro-indol-2-yl-carbonyl)-2,5-dimethylpiperazine
(trans)-4-(4-Fluorobenzyl)-1-(6-methyl-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
(trans)-4-(4-Fluorobenzyl)-1-(6-trifluoromethoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
(trans)-1-(5-Chloro-6-methoxy-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Bromo-6-methoxy-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Chloro-6-methyl-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Bromo-6-methyl-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5,6-Dichloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(6-Bromo-5-chloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Bromo-6-chloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Chloro-6-trifluoromethyl-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
(trans)-1-(5-Chloro-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0029] Examples of the preferred compounds of the invention in the above formula (I) are shown in the following Table 1.
TABLE 1 Compound No. Structure 3.1 4.1 3.9 3.13 3.14 3.15 3.16 3.18 3.19 3.20 3.21 3.22 3.23
DEFINITIONS
[0030] The term “therapy” and “treatment” as used herein includes prophylaxis as well as relieving the symptoms of disease.
[0031] Unless specified otherwise:
[0032] “Halo” or “halogen” refers to fluoro, chloro, bromo or iodo.
[0033] “Nitro” refers to the radical —NO 2 .
[0034] CHCl 3 refers to chloroform.
[0035] CH 2 Cl 2 refers to dichloromethane.
[0036] The descriptor “trans” indicates that the two methyl groups are located on opposite sides of the piperazine plane. The descriptor “cis” indicates that the two methyl groups are located at the same side of the piperazine plane.
[0000] Structure Activity Relationship
[0000] Prior Art and Reference Compounds
[0037] (cis)-4-(4-Fluorobenzyl)-1-(7-methoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine,
4-(4-fluorobenzyl)-1-(indol-2-yl-carbonyl)-piperazine, 4-(4-chlorobenzyl)-1-(benzofuran-2-yl-carbonyl)-piperazine and (trans)-4-(4-fluorobenzyl)-1-(7-methoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine are included as prior art and reference compounds hereinafter called Compound A, B, C and D respectively. Compound A is described in the International Patent Application WO 0164676. Compound C is described in U.S. Pat. No. 4,115,569. Compound B and D are reference compounds, not according to the invention.
[0038] Compared to the prior art Compounds A, and C and reference Compounds B and D, the compounds of the invention were much stronger inhibitors in the Ca 2+ -flux assay. The improved potency of the compounds correlates amongst others to the following structural features.
1. The introduction of chloro or preferably fluoro in p-position of the benzylpiperazine moiety is crucial to gain activity in the nano molar range of the Ca 2+ -flux assay. The replacement of X with another functional group, e.g., alkyl, or hydrogen decreases the potency and the affinity. 2. The two methyl groups in 2,5-position are in trans-configuration. The replacement of the methyl groups in trans-2,5-position by a substitution with hydrogen as well as changing the orientation to a cis-2,5 substitution, dramatically decreases the potency of the compounds in the Ca 2+ -flux assay. 3. R 1 has to be a group with a molrefractory (MR) value of 5.0≦MR≦9.0, such as chloro, bromo, methyl, nitro or trifluoromethyl. 4. The 4- and 7-position of the benzofuran and indole ring systems must not be substituted.
[0043] The invention, combining the features according to 1, 2, 3 and 4 above, provides compounds having a surprising and unexpected potency (see Table 2).
[0044] The compounds of the invention showed favourable pharmacokinetic properties.
[0045] A definition of the MR conception and the values thereof are available in the following two references:
[0046] Hansch, C., and Leo, A., In Exploring QSAR: Fundamentals and Applications in Chemistry and Biology. ACS, Washington, D.C. 1995. Hansch, C., Leo, A., and Hoekman, D., In Exploring QSAR: Hydrophobic, Electronic, and Steric Constants. ACS, Washington, D.C. 1995.
[0000] Preparation of Compounds
[0047] The present invention further provides a process for the preparation of a compound of formula (I) by the method given below.
Method:
[0048] The compounds of formula (I) may be prepared by treating the piperazine derivative of formula (II), wherein X is defined in formula (I), with a compound of formula (III), wherein L 1 is a leaving group (e.g. a halide such as chloride, a hydroxyl, a benzotriazol-1-yl ester, an isourea group) and Y, R 1 and R 2 are defined in formula (I). The process of the invention may conveniently be carried out in CH 2 Cl 2 or CHCl 3 at a temperature of, for example, 0° C. or above such as 20 to 120° C.
[0049] Most preferred is a process where the amine derivative of formula (II) in chloroform is treated with an excess molar amount of a compound of formula (III), wherein L 1 is a hydroxy group, in the presence of an excess molar amount of a carbodiimide, such as N-cyclohexyl-carbodiimide, N′-methylpolystyrene, and 1-hydroxybenzotriazol. The reaction mixture is stirred at a temperature typically in the range from 60° C. to 150° C. under a time typically in the range from 100 to 1000 seconds in a microwave oven (Smith Synthesiser from Personal Chemistry). Under these conditions the yields improve up to 99%. Compounds of formula (II) may be obtained via a known protocol described e.g., in Tabia et al., J. Med. Chem. 1999, 42, 2870. Compounds falling within the scope of formula (II) may be prepared by methods, which are generally analogous to those of said literature. Compounds of the formula (III) are commercially available or are described in Example 1, Example 2, and Example 4. Compounds falling within the scope of formula (III) may be prepared by methods, which are generally analogous to those of said literature (Hodeges et al., J. Med. Chem. 1981, 24, 1184; Hino et al., Chem. Pharm. Bull. 1990, 38, 59) or according to Example 1, Example 2, and Example 4.
[0050] The present invention can also use acidic adducts of the dimethyl-piperazine derivatives with acids including for example hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, carbonic acid, malic acid, citric acid, fumaric acid, tartaric acid, oxalic acid, methanesulfonic acid, p-toluenesulfonic acid, trifluoroacetic acid and others. Lists of additional suitable salts are found in Remington's Pharmaceutical Sciences, 17.th edition, Mack Publishing Company, Easton, Pa., 1985, p. 1418.
EXAMPLE 1
5-Bromo-1-benzofuran-2-carboxylic Acid
[0051] To a solution of 5-bromosalicylaldehyde (20 g, 98.5 mmol) and diethyl bromomalonate (95%, 37 g, 148 mmol) in butanone (200 mL) potassium carbonate (27.5 g, 197 mmol) was added. The mixture was refluxed for 4 h and allowed to attain room temperature. Potassium carbonate was filtered off and the solvent was removed in vacuo. The residue was participated between CH 2 Cl 2 and 1M aqueous H 2 SO 4 . The organic layer was dried and concentrated to give an oil. The oil was treated with 10% KOH/EtOH (125 mL) and refluxed for 45 minutes. The reaction mixture was concentrated and 2M aqueous H 2 SO 4 (350 mL) was added and the mixture was warmed to 90° C. After cooling to room temperature, the product precipitated and was re-crystallised in EtOH/H 2 O (4:1) (yield: 6.6 g, 28%).
[0052] 1 H NMR: δ (DMSO-d 6 ) 13.55 (bs, 1H), 7.97 (d, 1H), 7.67 (d, 1H), 7.60 (m, 2H).
[0053] Other 1-benzofuran-2-carboxylic acid can be obtained in a similar manner.
EXAMPLE 2
5,6-Dichloro-1-indole-2-carboxylic Acid
[0054] To an ice-cooled mixture of 3,4-dichlorotoluene (10.0 g, 62.1 mmol) and sulfuric acid (96-98%, 50 mL) nitric acid (100%, 2.87 mL, 68.3 mmol) was added dropwise under vigorous stirring at such a rate that the reaction temperature did not exceed 15° C.
[0055] After the addition the reaction mixture was allowed to reach room temperature and was stirred for an additional 60 minutes. The reaction mixture was poured onto 250 mL of ice and the precipitated product was isolated by filtration with suction, washed with water, dried under vacuum and finally re-crystallized from heptane (yield of 4,5-dichloro-2-nitrotoluene: 4.4 g, 34%).
[0056] 1 H NMR: δ (CDCl 3 ) 8.10 (s, 1H); 7.65 (s, 1H); 2.57 (s, 3H).
[0057] To a solution of 4,5-dichloro-2-nitrotoluene (2.0 g, 9.7 mmol) in CCl 4 (15 mL) was added N-bromosuccinimide (2.6 g, 15 mmol) and Bz 2 O 2 (50 mg). The reaction mixture was refluxed for 120 hours and then allowed to reach room temperature. The reaction mixture was washed twice with water, dried and concentrated to yield 3.54 g of a crude product consisting of approximately 70% of 4,5-dichloro-2-nitrobenzyl bromide and 30% of 4,5-dichloro-2-nitrobenzyl dibromide. This mixture was suspended in a mixture of 1,4-dioxane (35 mL) and water (35 mL). CaCO 3 (6.2 g, 62 mmol) was added and the reaction mixture was refluxed for 18 hours. The reaction mixture was allowed to reach room temperature and was then concentrated to dryness. To a suspension of the remainder in CH 2 Cl 2 (50 mL) was added 2M aqueous HCl until no solid remained. The aqueous layer was extracted with CH 2 Cl 2 and the combined organic layer was dried and concentrated. The crude product was dissolved in toluene and purified by flash chromatography using silica gel 60 and heptane/ethyl acetate (19:1>4:1) (yield of 4,5-dichloro-2-nitrobenzyl alcohol: 1.15 g, 53%).
[0058] 1 H NMR: δ (CDCl 3 ) 8.27 (s, 1H); 7.98 (s, 1H); 5.02 (s, 2H).
[0059] To a solution of 4,5-dichloro-2-nitrobenzyl alcohol (1.15 g, 5.2 mmol) in CHCl 3 (20 mL) was added MnO 2 (4.0 g, 47 mmol). The reaction mixture was refluxed for 18 hours and then allowed to reach room temperature. The reaction mixture was filtered through Celite and concentrated (yield of 4,5-dichloro-2-nitrobenzaldehyde: 1.0 g, 87%).
[0060] 1 H NMR: δ (CDCl 3 ) 10.20 (s, 1H); 8.07 (s, 1H); 7.84 (s, 1H)
[0061] A solution of 4,5-dichloro-2-nitrobenzaldehyde (0.85 g, 3.85 mmol) and (carbethoxymethylene)-triphenylphosphorane (1.84 g, 5.55 mmol) in benzene (25 mL) was refluxed for three hours. The reaction mixture was allowed to reach room temperature and was then concentrated. The crude product was purified by flash chromatography using silica gel 60 and toluene (yield of ethyl (cis, trans)-4,5-dichloro-2-nitro cinnamate: 1.01 g, 90%).
[0062] Ethyl (cis, trans)-4,5-dichloro-2-nitro cinnamate (1.01 g, 3.48 mmol) was dissolved in triethyl phosphite (2 mL). The solution was added dropwise to triethyl phosphite (5 mL) at 125° C. After the addition the temperature was raised to 145° C. and the reaction mixture was left at this temperature for two hours. The reaction mixture was allowed to reach room temperature and was then concentrated. The crude product was purified by flash chromatography using silica gel 60 and heptane/toluene (10:1>5:1>1:1>0:1) (yield of ethyl 5,6-dichloroindole-2-carboxylate: 0.18 g, 20%).
[0063] 1 H NMR: δ (CDCl 3 ) 8.90 (bs, 1H); 7.81 (s, 1H); 7.57 (s, 1H); 7.16 (s, 1H); 4.48 (q, 2H); 1.45 (t, 3H).
[0064] To a solution of ethyl 5,6-dichloroindole-2-carboxylate (0.16 g, 0.64 mmol) in ethanol (99%, 5 mL) was added 1M aqueous NaOH (5 mL). The reaction mixture was refluxed for five minutes and was then allowed to reach room temperature. The ethanol was removed by evaporation and the aqueous residue was acidified using 1M aqueous HCl. The precipitated product was collected by filtration, washed with water and dried under vacuum (yield of 5,6-dichloroindole-2-carboxylic acid: 0.14 g, 96%)
[0065] 1 H NMR: δ (DMSO-d 6 ) 13.26 (bs, 1H); 12.06 (s, 1H); 7.94 (s, 1H); 7.60 (s, 1H); 7.07 (d, 1H).
[0066] Other indole-2-carboxylic acid can be obtained in a similar manner.
EXAMPLE 3
3.1 (trans)-1-(5-Bromo-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0067] A mixture of (trans)-1-(4-fluorobenzyl)-2,5-dimethyl-piperazine (220 mg, 1.0 mmol), 5-bromo-1-benzofuran-2-carboxylic acid (342 mg, 1.5 mmol), 1-hydroxybenzotriazol (200 mg, 1.5 mmol) and N-cyclohexylcarbodiimide, N′-methylpolystyrene (167 g, 3.0 mmol of the resin with a loading of 1.8 mmol/g) in CHCl 3 was heated under 5 minutes at 110° C. in a microwave oven. The mixture was allowed to attain room temperature, TBD-methyl polystyrene (1000 mg, 3 mmol of the resin with a loading of 2.9 mmol/g) was added and the mixture was agitated over night. Both resins were filtered off and washed with CHCl 3 and EtOAc. The filtrate was concentrated in vacuo and the residue was submitted to flash column chromatography (toluene→toluene:EtOAc, 20:1→toluene:EtOAc, 1:1) to give the title product in 93% yield.
[0068] 1 H NMR: δ (CDCl 3 ) 7.78 (d, 1H), 7.48 (dd, 1H), 7.38 (d, 1H), 7.33 (dd, 2H), 7.19 (s, 1H), 7.01 (dd, 2H), 4.63 (bs, 1H), 4.14 (bs, 1H), 3.62 (m, 2H), 3.46 (d, 1H), 3.08 (bs, 1H), 2.79 (dd, 1H) 2.30 (d, 1H), 1.43 (d, 3H), 1.06 (d, 3H).
[0069] The following compounds were prepared in a similar manner:
3.2 (trans)-1-(5-Chloro-benzofuran-2-yl-carbonyl)-4-(4-chlorobenzyl)-2,5-dimethylpiperazine
[0070] 1 H NMR: δ (CDCl 3 ) 7.62 (d, 1H), 7.43 (d, 1H), 7.33 (m, 1H), 7.29 (m, 4H), 7.19 (d, 1H), 4.63 (bs, 1H), 4.14 (bs, 1H), 3.54 (m, 3H), 3.08 (bs, 1H), 2.80 (dd, 1H), 2.29 (d, 1H), 1.43 (d, 3H), 1.06 (d, 3H).
3.3 (trans)-4-(4-Fluorobenzyl)-1-(5-nitro-indol-2-yl-carbonyl)-2,5-dimethylpiperazine
[0071] 1 H NMR: δ (CDCl 3 ) 9.67 (s, 1H), 8.65 (s, 1H), 8.20 (d, 1H), 7.49 (d, 1H), 7.35 (dd, 2H), 7.04 (dd, 2H), 6.92 (s, 1H), 4.81 (m, 1H), 4.33 (d, 1H), 3.57 (m, 3H), 3.15 (bs, 1H), 2.82 (dd, 1H), 2.35 (d, 1H), 1.51 (d, 3H), 1.07 (d, 3H).
3.4 (trans)-4-(4-Fluorobenzyl)-1-(5-nitro-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0072] 1 H NMR: δ (CDCl 3 ) 8.60 (d, 1H), 8.32 (dd, 1H), 7.61 (d, 1H), 7.34 (m, 3H), 7.02 (dd, 2H), 4.61 (bs, 1H), 4.15 (bs, 1H), 3.56 (m, 3H), 3.11 (bs 1H), 2.82 (dd, 1H), 2.33 (d, 1H), 1.46 (d, 3H), 1.08 (d, 3H).
3.5 (trans)-4-(4-Fluorobenzyl)-1-(7-methoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine (Reference Compound D)
[0073] 1 H NMR: δ (CDCl 3 ) 7.34 (dd, 2H), 7.27 (s, 1H), 7.20 (m, 2H), 7.01 (dd, 2H), 6.87 (dd, 1H), 4.69 (bs, 1H), 4.20 (bs, 1H), 3.99 (s, 3H), 3.62 (m, 2H), 3.46 (d, 1H), 3.07 (bs, 1H), 2.80 (dd, 1H) 2.30 (d, 1H), 1.43 (d, 3H), 1.07 (d, 3H).
3.6 (trans)-1-(5-Bromo-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0074] 1 H NMR: δ (CDCl 3 ) 10.17 (s, 1H), 7.77 (s, 1H), 7.36 (m, 4H), 7.04 (dd, 2H), 6.70 (d, 1H), 4.86 (m, 1H), 4.38 (d, 1H), 3.56 (m, 3H), 3.13 (bs, 1H), 2.81 (dd, 1H), 2.33 (d, 1H), 1.49 (d, 3H), 1.05 (d, 3H).
3.7 (trans)-4-(4-Fluorobenzyl)-1-(5-methyl-indol-2-yl-carbonyl)-2,5-dimethylpiperazine
[0075] 1 H NMR: δ (CDCl 3 ) 9.54 (s, 1H), 7.43 (s, 1H), 7.36 (m, 3H), 7.12 (d, 1H), 7.04 (dd, 2H), 6.70 (d, 1H), 4.88 (m, 1H), 4.40 (d, 1H), 3.56 (m, 3H), 3.12 (bs, 1H), 2.81 (dd, 1H), 2.46 (s, 3H), 2.32 (d, 1H), 1.49 (d, 3H), 1.06 (d, 3H).
3.8 (trans)-1-(5-Chloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0076] 1 H NMR δ (CDCl 3 ) 9.40 (s, 1H); 7.61 (d, 1H); 7.36 (d, 1H); 7.34 (dd, 2H); 7.23 (dd, 1H); 7.03 (m, 2H); 6.69 (d, 1H); 4.82 (m, 1H); 4.34 (d, 1H); 3.56 (m, 3H); 3.12 (m, 1H); 2.80 (dd, 1H); 2.32 (dd, 1H); 1.48 (d, 3H); 1.05 (d, 3H).
3.9 (trans)-4-(4-Chlorobenzyl)-1-(5-chloro-indol-2-yl-carbonyl)-2,5-dimethylpiperazine
[0077] 1 H NMR δ (CDCl 3 ) 9.35 (s, 1H); 7.61 (d, 1H); 7.35 (d, 1H); 7.32 (dd, 4H); 7.23 (dd, 1H); 6.69 (d, 1H); 4.81 (m, 1H); 4.34 (d, 1H); 3.56 (m, 3H); 3.12 (m, 1H); 2.80 (dd, 1H); 2.32 (dd, 1H) 1.48 (d, 3H); 1.05 (d, 3H).
3.10 (trans)-4-(4-Chlorobenzyl)-1-(5-nitro-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0078] 1 H NMR δ (CDCl 3 ) 8.60 (d, 1H); 8.33 (dd, 1H); 7.62 (d, 1H); 7.36 (d, 1H); 7.31 (dd, 4H); 4.61 (m, 1H); 4.12 (m, 1H); 3.56 (m, 3H); 3.11 (m, 1H); 2.82 (dd, 1H); 2.32 (dd, 1H); 1.46 (d, 3H) 1.08 (d, 3H).
3.11 (trans)-1-(5-Bromo-benzofuran-2-yl-carbonyl)-4-(4-chlorobenzyl)-2,5-dimethylpiperazine
[0079] 1 H NMR δ (CDCl 3 ) 7.79 (d, 1H); 7.49 (dd, 1H); 7.39 (d, 1H); 7.31 (dd, 4H); 7.20 (d, 1H); 4.63 (m, 1H); 4.14 (m, 1H); 3.55 (m, 3H); 3.09 (m, 1H); 2.80 (dd, 1H); 2.30 (d, 1H); 1.44 (d, 3H); 1.07 (d, 3H).
3.12 (trans)-4-(4-Fluorobenzyl)-1-(5-methyl-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0080] 1 H NMR δ (CDCl 3 ) 7.51 (d, 1H); 7.34 (dd, 2H); 7.31 (s, 1H); 7.23 (d, 1H); 7.12 (d, 1H); 7.02 (t, 2H); 4.67 (bs, 1H); 4.21 (bd, 1H); 3.63 (d, 1H); 3.58 (bs, 1H); 3.46 (d, 1H); 3.08 (bs, 1H); 2.80 (dd, 1H); 2.49 (s, 3H); 2.29 (d, 1H); 1.43 (d, 3H); 1.07 (d, 3H).
3.13 (trans)-4-(4-Fluorobenzyl)-1-(6-methyl-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0081] 1 H NMR δ (CDCl 3 ) 7.42 (s, 1H); 7.38 (d, 1H); 7.34 (dd, 2H); 7.20 (m, 2H); 7.02 (t, 2H); 4.68 (bs, 1H); 4.20 (bd, 1H); 3.63 (d, 1H); 3.59 (bs, 1H); 3.51 (d, 1H); 3.08 (bs, 1H); 2.79 (dd, 1H) 2.32 (s, 3H); 2.29 (d, 1H); 1.43 (d, 3H); 1.06 (d, 3H).
3.14 (trans)-4-(4-Fluorobenzyl)-1-(6-trifluoromethoxy-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0082] 1 H NMR δ (CDCl 3 ) 7.51 (m, 2H); 7.28 (dd, 2H); 7.25 (m, 2H); 7.02 (t, 2H); 5.23 (bs, 1H); 4.15 (bs, 1H); 3.63 (d, 1H); 3.58 (bs, 1H); 3.47 (d, 1H); 3.09 (bs, 1H); 2.80 (dd, 1H); 2.31 (d, 1H); 1.44 (d, 3H); 1.07 (d, 3H).
3.15 (trans)-1-(5-Chloro-6-methoxy-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0083] 1 H NMR δ (CDCl 3 ) 7.63 (s, 1H); 7.34 (dd, 2H); 7.17 (s, 1H); 7.06 (s, 1H); 7.00 (t, 2H); 4.66 (bs, 1H); 4.19 (bd, 1H); 3.95 (s, 3H); 3.63 (d, 1H); 3.59 (bd, 1H); 3.47 (d, 1H); 3.08 (bs, 1H); 2.80 (dd, 1H); 2.30 (d, 1H); 1.43 (d, 3H); 1.07 (d, 3H).
3.16 (trans)-1-(5-Bromo-6-methoxy-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0084] 1 H NMR δ (CDCl 3 ) 7.81 (s, 1H); 7.34 (dd, 2H); 7.16 (s, 1H); 7.04 (s, 1H); 7.02 (t, 2H); 4.65 (bs, 1H); 4.19 (bd, 1H); 3.95 (s, 3H); 3.62 (d, 1H); 3.58 (bd, 1H); 3.47 (d, 1H); 3.08 (bs, 1H); 2.80 (dd, 1H); 2.30 (d, 1H); 1.43 (d, 3H); 1.07 (d, 3H).
3.17 (trans)-4-(4-Fluorobenzyl)-1-(6-methoxy-5-nitro-benzofuran-2-yl-carbonyl)-2,5-dimethylpiperazine
[0085] 1 H NMR δ (CDCl 3 ) 8.17 (s, 1H); 7.34 (dd, 2H); 7.24 (s, 1H); 7.17 (s, 1H); 7.02 (t, 2H); 4.62 (bs, 1H); 4.13 (bs, 1H); 3.63 (d, 1H); 3.59 (bs, 1H); 3.47 (d, 1H); 3.10 (bs, 1H); 2.80 (dd, 1H) 2.32 (d, 1H); 1.44 (d, 3H); 1.07 (d, 3H).
3.18 (trans)-1-(5-Chloro-6-methyl-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0086] 1 H NMR δ (CDCl 3 ) 7.62 (s, 1H); 7.38 (s, 1H); 7.34 (dd, 2H); 7.17 (s, 1H); 7.00 (t, 2H); 4.63 (bs, 1H); 4.16 (bs, 1H); 3.63 (d, 1H); 3.58 (bd, 1H); 3.46 (d, 1H); 3.08 (bs, 1H); 2.79 (dd, 1H); 2.49 (s, 3H); 2.30 (d, 1H); 1.43 (d, 3H); 1.06 (d, 3H).
3.19 (trans)-1-(5-Bromo-6-methyl-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0087] 1 H NMR δ (CDCl 3 ) 7.82 (s, 1H); 7.40 (s, 1H); 7.34 (dd, 2H); 7.16 (s, 1H); 7.02 (t, 2H); 4.63 (bs, 1H); 4.15 (bs, 1H); 3.62 (d, 1H); 3.59 (bs, 1H); 3.46 (d, 1H); 3.08 (bs, 1H); 2.79 (dd, 1H); 2.51 (s, 3H); 2.29 (d, 1H); 1.43 (d, 3H); 1.06 (d, 3H).
3.20 (trans)-1-(5,6-Dichloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0088] 1 H NMR δ (CDCl 3 ) 9.31 (bs, 1H); 7.72 (s, 1H); 7.54 (s, 1H); 7.34 (dd, 2H); 7.03 (t, 2H); 6.67 (d, 1H); 4.79 (bs, 1H); 4.31 (bd, 1H); 3.63 (d, 1H); 3.58 (bs, 1H); 3.47 (d, 1H); 3.12 (bs, 1H); 2.79 (dd, 1H); 2.32 (d, 1H); 1.47 (d, 3H); 1.05 (d, 3H).
3.21 (trans)-1-(6-Bromo-5-chloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0089] 1 H NMR δ (CDCl 3 ) 9.38 (bs, 1H); 7.73 (s, 1H); 7.72 (s, 1H); 7.34 (dd, 2H); 7.03 (t, 2H); 6.66 (d, 1H); 4.78 (bs, 1H); 4.31 (bd, 1H); 3.63 (d, 1H); 3.58 (bs, 1H); 3.47 (d, 1H); 3.12 (bs, 1H) 2.79 (dd, 1H); 2.32 (d, 1H); 1.47 (d, 3H); 1.05 (d, 3H).
3.22 (trans)-1-(5-Bromo-6-chloro-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0090] 1 H NMR δ (CDCl 3 ) 9.60 (bs, 1H); 7.89 (s, 1H); 7.57 (s, 1H); 7.35 (dd, 2H); 7.03 (t, 2H); 6.66 (s, 1H); 4.79 (bs, 1H); 4.32 (bd, 1H); 3.63 (d, 1H); 3.59 (bs, 1H); 3.47 (d, 1H); 3.12 (bs, 1H); 2.80 (dd, 1H); 2.33 (d, 1H); 1.47 (d, 3H); 1.05 (d, 3H).
3.23 (trans)-1-(5-chloro-6-trifluoromethyl-indol-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0091] 1 H NMR δ (CDCl 3 ) 9.93 (bs, 1H); 7.82 (s, 1H); 7.75 (s, 1H); 7.35 (dd, 2H); 7.03 (t, 2H); 6.72 (d, 1H); 4.80 (bs, 1H); 4.33 (bd, 1H); 3.67 (bs, 1H); 3.64 (d, 1H); 3.48 (d, 1H); 3.13 (bs, 1H); 2.81 (dd, 1H); 2.34 (d, 1H); 1.49 (d, 3H); 1.05 (d, 3H).
EXAMPLE 4
4.1 (trans)-1-(5-Chloro-benzofuran-2-yl-carbonyl)-4-(4-fluorobenzyl)-2,5-dimethylpiperazine
[0092] A solution of 5-chloro-1-benzofuran-2-carboxylic acid (827 mg, 4.2 mmol) in thionyl chloride (4 mL) was refluxed over night. The solvent was removed in vacuo to give the 5-chloro-1-benzofuran-2-carbonyl chloride in quantitative yield.
[0093] To an ice cold solution of (trans)-1-(4-fluorobenzyl)-2,5-dimethylpiperazine (712 mg, 3.2 mmol) and triethylamine (506 mg, 5 mmol) in CH 2 Cl 2 (5 mL) a solution of the 5-chloro-1-benzofuran-2-carbonyl chloride (4.2 mmol) in CH 2 Cl 2 (2 mL) was dropwise added. The reaction mixture was stirred at room temperature over night and washed with 0.5 M aqueous NaOH. The organic layer was dried, concentrated and submitted to flash column chromatography (CHCl 3 /MeOH; 1:0→10:1) to yield 1.05 g (82%) of the title compound.
[0094] 1 H NMR: δ (CDCl 3 ) 7.59 (d, 1H), 7.40 (d, 1H), 7.31 (m, 3H), 7.17 (d, 1H), 6.99 (dd, 2H), 4.61 (bs, 1H), 4.12 (bs, 1H), 3.60 (m, 2H), 3.44 (d, 1H), 3.06 (bs, 1H) 2.77 (dd, 1H), 2.28 (d, 1H), 1.41 (d, 3H), 1.04 (d, 3H)
[0000] Pharmacological Methods
[0000] In Vitro Assay
[0095] In the competitive affinity binding assay, the binding affinity of the compounds for the CCR1 receptor can be determined by measuring their ability to displace 125 I-Mip-1□ from the CCR1 receptor.
[0096] The binding of Mip-1α at the CCR1 receptor leads to an increase of intracellular calcium levels. The ability of the compounds of the invention to block this biologic response of the CCR1 receptor is determined in the Ca 2+ -flux assay.
[0000] In Vitro Competitive Affinity Binding Assay
[0000] Reagents and Solutions:
[0000]
1. Screen Ready™ Targets: cloned human CCR1 Chemokine receptor, expressed in CHO cells, coated on 96-well FlashPlate® (Perkin Elmer Cat #6120525)
2. Ligand: 125 I-MIP-1α from Perkin Elmer (specific activity is 2200 Ci/mmol) was reconstituted to 25 μCi/mL in H 2 O.
3. Assay buffer: 50 mM HEPES, 1 mM CaCl 2 , 5 mM MgCl 2 , 0.2% BSA, pH 7.4.
4. MIP-1α (Peprotech EC Ltd Cat # 300-08)
5. The compounds of the invention were dissolved in DMSO. A serial dilution was made and ten concentrations of each compound were screened to generate a dose curve from which the IC 50 value was determined.
Assay Procedure:
[0102] Membranes coated on the FlashPlate® were incubated with 125 I-MIP-1α in the presence and absence of different concentrations of compounds at ambient temperature for 1 hour. The radioactivity in each well was determined in a microplate scintillation counter. The non-specific binding was defined by binding in the presence of 1250-fold unlabeled MIP-1α. The assay was performed according to the manufacturer's instruction of Screen Ready™ Targets. The compounds of the invention, when tested in this assay demonstrated affinity to the CCR1 receptor.
[0000] In vitro Ca 2+ -Flux Assay on Human Monocytes
[0000] Reagents and Solutions:
[0000] 1. Cell culture:
[0000]
a) THP-1 (ATCC Cat# TIB202)
b) Tissue culture medium: RPMI 1640 with Ultraglutamine 1 supplemented with 10% (v/v) foetal calf serum. This medium is hereinafter referred to as “growth medium”.
2. Assay buffer: HBSS (Hanks' balanced salts solution), 20 mM HEPES, 1 mM CaCl 2 , 1 mM MgCl 2 , 2.5 mM Probenecid, pH 7.4.
3. Fluo-4AM (Molecular Probes Cat # F14201)
4. Pluronic F-127 (Molecular Probes Cat # P-6867)
5. The compounds of the invention were dissolved in DMSO. A serial dilution was made and nine concentrations of each compound were screened to generate a dose curve from which the IC 50 value was determined.
6. MIP-1α (Peprotech EC Ltd Cat # 300-08)
7. Victor 2 1420 (Perkin Elmer)
8. Microlite™ 2+ (Dynex Cat # 7572)
Assay Procedure:
[0105] THP-1 cells were grown in T-75 cm 2 flasks in growth medium at 37° C. in 5% CO 2 . The cells were harvested by centrifugation and resuspended in assay buffer. The cells were then loaded with 5 μM Fluo-4 and 0.02% pluronic acid (final concentrations) at 37° C. in 5% CO 2 for 30 min. The excess dye was removed by washing with assay buffer. The cells were resuspended and 10 5 cells/well were added in a Microlite plate containing compounds and then incubated for 15 minutes at 37° C. in 5% CO 2 . The cells were then stimulated with MIP-1α and changes in intracellular free Ca 2+ concentration were measured with a Victor 2 . The compounds of the invention, when tested in this assay, demonstrated the ability to inhibit the MIP-1α mediated Ca 2+ mobilisation in THP-1 cells.
[0000] In Vivo Bioavailability in the Mouse
[0106] Female mice (SJL/N Tac) were given a single intravenous or oral dose of a mixture of 5 or 6 compounds per cassette (nominal dose: 1 mg/kg/compound) in a solution containing 0.5% N,N′-dimethylacetamide (DMA) and 15% sulfobutyl ether β-cyclodextrin (Captisol®). Blood samples were taken from one mouse per time point and dose group until 24 hour after respective administration. The dose formulations and plasma concentrations of each compound were determined by LC-MS/MS. The pharmacokinetic parameters were determined by non-compartmental analysis using WinNonlin Professional (version 4.0.1). The elimination rate constant, λ, was estimated by linear regression analysis of the terminal slope of the logarithmic plasma concentration-time curve. The area under the plasma concentration-time curve, AUC 0-t , was calculated by using the linear/logarithmic trapezoidal rule. The AUC inf was calculated with the residual area estimated as C z /λ. The calculated plasma concentration at the last time point, C z , was obtained from the regression equation.
[0107] The oral bioavailability (F) was calculated as:
F oral =( AUC inf,po /AUC inf,iv )·(Dose iv /Dose po )
Pharmacodynamic Assays
Using the procedures set forth in Horuk, R. and Ng, H. Med. Res. Rev. 2000, 20, 155 and Horuk, R. Methods, 2003, 29, 369 and references therein, the therapeutic efficacy of the compounds according to the invention for the treatment of inflammatory, autoimmune, proliferative or hyperproliferative diseases such as rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease or asthma are shown.
[0108] Accordingly, in one embodiment of the invention a composition is provided comprising the compounds of formula I for the treatment of inflammatory, autoimmune, proliferative or hyperproliferative diseases.
[0000] The synergistic effect of combining the compounds according to the invention and cyclosporin A also is shown by use of methods mentioned in said references.
[0109] Accordingly, in one embodiment of the invention a composition is provided comprising the compounds of formula I in combination with a sub-nephrotoxic amount of cyclosporin A.
[0110] Using the procedures set forth in the competitive affinity binding assay and the Ca 2+ -flux assay, various compounds of the invention were tested for their ability to block Ca 2+ -flux (IC 50 Ca ). The results of some examples and the Compounds A, B, C, and D are shown in Table 2 where all IC 50 -values are given in nM (nano Molar). Table 2 exemplifies the invention without limiting the scope thereof.
TABLE 2 Compound Structure IC 50 Ca Compound A Prior art >1000 Compound D Reference >1000 3.1 Invention 12 3.13 Invention 20 Compound C Prior art >1000 Compound B Reference >1000 3.20 Invention 15 Footnote: All 2,5-dimethylpiperazine derivatives have been synthesized and tested as racemic mixtures.
[0111] The compounds of the invention show oral bioavailability in the mouse. Using the procedures set forth in the in vivo bioavailability assay, various compounds of the invention were tested for their clearance (CL; L/h/kg), plasma half-life (t 1/2 ; hrs) as well as oral bioavailability (F; %) after administration of the nominal dose of 1 mg/kg of each compound. The results of some examples are shown in Table 3. Table 3 exemplifies the invention, without limiting the scope thereof.
TABLE 3 CL t 1/2 F Compound Structure (L/h/kg) (hrs) (%) 3.1 0.9 7.0 53 4.1 2.6 4.8 72
Administration
[0112] Effective quantities of the compounds of formula (I) are preferably administered to a patient in need of such treatment according to usual routes of administration and formulated in usual pharmaceutical compositions comprising an effective amount of the active ingredient and suitable pharmaceutical constituents. Such compositions may take a variety of forms, e.g. solutions, suspensions, emulsions, tablets, capsules, and powders prepared for oral administration, sterile solutions for parental administration, suppositories for rectal administration or suitable topical formulations. Conventional procedures for the selection and preparation of suitable pharmaceutical formulations are described, for example, in Pharmaceuticals—The Science of Dosage Form Design, M. B. Aulton, Churchill Livingstone, 1988.
[0113] A suitable daily dose for use in the treatment of RA is contemplated to vary between 0.005 mg/kg to about 10 mg/kg body weight, in particular between 0.025 mg/kg to 2 mg/kg body weight, depending upon the specific condition to be treated, the age and weight of the specific patient, and the specific patient's response to the medication. The exact individual dosage, as well as the daily dosage, will be determined according to standard medical principles under the direction of a physician. | Compounds of formula (I)
wherein X is a fluorine or a chlorine atom; the methyl groups located at the 2- and 5-position of the piperazine ring are in trans-configuration to each other; Y is NH or O;
R 1 is selected from hydrogen, chloro, bromo, nitro, methyl or trifluoromethyl;
R 2 is selected from hydrogen, halo, methyl, trifluoromethyl, methoxy or trifluoromethoxy;
or a pharmaceutically acceptable salt or solvate thereof; The invention also relates to pharmaceutical compositions containing a compound of formula (I) together with a pharmaceutically acceptable carrier. Included are also processes for the preparation of compounds of formula (I), as well as methods for treating mammals suffering from inflammatory, autoimmune, proliferative or hyperproliferative diseases by administering a compound having the formula (I) to said mammal. | 2 |
RIGHTS OF THE GOVERNMENT
This invention described herein may be manufactured, used, and licensed by or for the United States Government for governmental purposes without the payment to us of any royalty thereon.
BACKGROUND OF THE INVENTION
The present invention relates to phase comparators and more particularly to phase comparator having an output for a matched phase condition or an output for a 180° out-of-phase condition.
Phase comparators, discriminators, and detectors which respond to the phase difference between two signals are not new. Phase detectors which detect the interval between homologous edges of waveforms are disclosed in several prior art patents. One, such as U.S. Pat. No. 3,805,153 to Gallant, develops a voltage proportional to this phase difference. Others such as U.S. Pat. No. 3,599,102 to G. Mous produce pulses whose width is representative of the phase difference between the inputs. Another, U.S. Pat. No. 3,328,688 to Brooks, compares the leading edge of first of the wave signals to the trailing edge of the other and also compares the leading edge of the second signal to the trailing of the edge of the first signal to obtain a rectangular pulse whose width is proportional to the degree of phase difference.
One problem with these prior art patents is their relatively low resistance to perturbations caused by noisy environments. There are several phase detectors which have been proposed such as that disclosed in U.S. Pat. No. 3,764,902 to T. Rodine which attempt to solve this problem; however, their circuitry tends to be quite complex or unsuited for many applications.
There are also many instances, especially in military and industrial applications, when the circuit need only discriminate or detect phase at one point. That is, when the input signals are 180° out-of-phase or in other cases when the signals are exactly in-phase. At all other phase relationships the determination that the two signals are not at that selected phase relationship need only be made. Additionally, it is often necessary that the circuitry be as efficiently designed as possible, considering durability, power requirements, simplicity, and noise immunity.
The present invention utilizes a network which can be readily miniaturized and makes use of both edges of the input waveforms to provide a simple logical output indicative of the selected phase relationship. It also has that capability of being utilized in environments requiring a high degree of noise immunity.
SUMMARY OF THE INVENTION
It is therefore one object of this invention to provide a phase discriminator circuit which utilizes logic circuitry to indicate phase relationships.
Another object of this invention is to provide a phase discriminator circuit which exhibits economy of design and can easily be miniaturized.
A further object of this invention is to provide phase comparison circuitry which is capable of operating in a high noise environment.
Yet another object of this invention is to provide a circuit operative at varying frequencies which determines whether two signal inputs are 180° out-of-phase or in-phase.
The foregoing and other objects are attained in accordance with one aspect of the present invention through the provision of an electronic apparatus using logic gates and bi-stable elements which act on each transition of two input signals and produce a logic output indicative of phase relationship.
BRIEF DESCRIPTION OF THE DRAWINGS
Various objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description of the present invention when considered in connection with the accompanying drawings in which:
FIG. 1 illustrates schematically the phase discriminator network for the 180° out-of-phase condition upon which this invention is based.
FIG. 2 illustrates graphically the case where inputs into the discriminator are exactly in-phase.
FIG. 3 illustrates graphically the case where the inputs into the discriminator are other than in-phase or 180° out-of-phase.
FIG. 4 illustrates graphically the case where the inputs into the discriminator are 180° out-of-phase and the system is subject to noise.
FIG. 5 illustrates schematically an alternate embodiment of one section of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic illustration of the phase discriminator network upon which the invention is based. Fundamentally, the system can be broken into three logic blocks. As depicted in the figure, blocks Ia and Ib generate pulses at each transition of their input signals. Block II determines whether these pulses occur concurrently or not. If they do, the inputs are either in-phase or 180° out-of-phase. Block III discriminates against either in-phase or out-of-phase signals and produces a high output based upon which type of signal one wishes to discriminate against. In this embodiment a logic high is obtained when the signals are 180° out-of-phase.
In elaborating upon the performance of each of these blocks reference will additionally be made to FIGS. 2, 3 and 4 which illustrate waveforms which are helpful in understanding the operation of this device. FIG. 2 illustrates waveforms that are in-phase, FIG. 3 illustrates waveforms that are other than in or 180° out-of-phase, and FIG. 4 illustrates the 180° out-of-phase case.
Blocks Ia and Ib are identical, each comprising NAND gate 12 (a,b), NOR gate 14 (a,b), an exclusive OR gate 16 (a,b) and a capacitor C 1 (a,b). Basically, gates 12 and 14 and capacitor C 1 form a delay circuit so that when inputs A and B in FIGS. 2, 3 and 4 undergo a transition, either high to low or low to high, the signal in that line reaches gate 16 behind the signal that is fed straight through. Therefore, exclusive OR gate 16 goes high and produces a pulse whose duration is determined by capacitor C 1 and the gates natural impedance. This is illustrated in waveforms C and D of FIGS. 2, 3 and 4.
Block II comprises two NOR gates 22 and 26, NAND gate 24, and two "D type" flip-flops 28 and 29 such as the type manufactured by RCA (CD4013AE). The flip-flops are triggered on the leading edge of the waveforms and as seen on FIGS. 2, 3 and 4 a logic high is produced when the pulses occur concurrently. Flip-flop 28 receives its clock pulse from C and D thru NOR gate 22 and thus is only triggered when either C or D are in a transition to low. Flip-flop 29 receives the signals from C and D through a NAND and NOR gate and therefore is triggered only when C and D are both high. Since the data input of flip-flop 29 is constantly at a high, Q at the upward transition of the clock pulse will be high and Q low. The data point of bistable 28 therefore is low. The Q output of flip-flop 29 is also connected through a resistor R 2 to its reset and through capacitor C 2 to ground. Thus when Q produces a high output it triggers the reset after a period determined by the time constant rendered by C 2 and R 2 . C 2 and R 2 are chosen such that the time duration is slightly longer than the pulse widths produced in blocks Ia and b. Then the reset acts to send Q from low to high, and the data input of flip-flop 28 which joined with Q of flip-flop 29 goes high also. Thus Q of bistable 28 will be high if its clock pulse occurs during the period when the RC delay circuit of flip-flop 29 is still charging (see E of FIGS. 2 and 4). However, if it occurs at any other time Q will go low and stay low as long as the pulses are not in concurrence.
Block III uses exclusive OR gate 34 to discriminate against input signals that are in-phase. As illustrated in F of FIGS. 2, 3 and 4, exclusive OR gate 34 has a "low" logic level for in-phase signal, a high logic level for 180° out-of-phase signals, and a mixture of high and low logic levels for other phase relationships. If one's wish was to obtain a discriminator for in-phase signals, one would simply invert either input into gate 34. The output from exclusive OR gate 34 and the output E from block II are applied to NAND gate 32. Both inputs to this NAND gate are a logic "high" only when the input square waves are 180° out-of-phase. After the output from 32 is inverted by 36, as seen on G of FIGS. 2, 3 and 4, a logic high is obtained at the output only when and for as long as the input signals are 180° out-of-phase.
Further reference is made to FIG. 4 which illustrates the 180° out-of-phase case with noise. Generally, due to jamming, system noise, and other deletorious effects signals tend to be "rough" at both up and down transitions of the waveform. As depicted in FIG. 4 the system described above rather successfully copes with this problem. Only a few minor perturbations (40) appear in what is otherwise a clean signal. These glitches generally will be washed out in processing or can be filtered out.
If a more precise examination is required block Ia and Ib can be modified so as to produce a clean pulse. As seen in FIG. 5 blocks Ia and Ib each can be replaced by flip-flops 1 and 2 which alternately trigger on the leading and falling edges of one of the input signals. Flip-flop 1 is triggered by the leading edge and 2 through NOR gate 3 by the trailing edge. These flip-flops are retriggerable to allow for a single output pulse on a noisy signal and to allow for upper frequency cut-off and noise cutoff. The pulses produced are sent through NAND gate 4 to yield a pulse train coinciding with each rise and fall of the input signal. The pulse width of flip-flop 1 is determined by R 11 and C 11 , and the width of flip-flop 2 is determined by R 22 and C 22 . C 1 , R 1 and its transistor and C 2 , R 2 and its transistor act on an upward transition to "reset" C 11 and C 22 . The operation of the flip-flop is otherwise very similar to flip-flop 29 of FIG. 1. Likewise the operation of the entire device in this modified form is now very similar to that of FIG. 1 except the perturbations will be ameliorated.
Flip-flop pulse widths should be selected on a system basis taking into account bandwidths and tolerance on active phase shifters. The two "D" type flip-flops and associated components labeled 1 and 2 in FIG. 5 may be replaced by a retriggerable monostable.
The logic circuitry and configuration disclosed herein, of course can be substituted with equivalent circuitry without departing from the spirit and scope of the invention. Additionally numerous variations and modifications of the present invention are possible in light of the above teachings. | An apparatus for providing a logical output indicative of when a signal isither in-phase with a reference signal or alternately 180° out-of-phase with a reference signal. Pulses are produced at each transition of the waveforms to be compared. A determination of their concurrence is then made and compared with a logical result of the inputs whereby a logical output indicative of whether the signals are in-phase or 180° out-of-phase is generated. | 6 |
This application is a continuation of application Ser. No. 069,724 filed June 7, 1987, now abandoned.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. Pat. No. 4,699,008 filed Mar. 26, 1986 and U.S. Pat. No. 9,670,029 filed May 12, 1986; U.S. Pat. No. 879,015 filed June 26, 1986; U.S. Pat. No. 878,649 filed June 26, 1986 and U.S. Pat. No. 878,817 filed June 26, 1986 all assigned to Westinghouse.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an apparatus for removing air trapped in a bottle bore of a shaft and, more particularly, includes an expandable bladder which displaces the trapped air and allows it travel up the tilted shaft.
2. Description of the Related Art
The present invention is used with an ultrasonic inspection system for inspecting the bore of a turbine or generator rotor shaft. Such an inspection system is described in detail in the above-listed U.S. patents. Such rotors are very large and may be as much as 45 feet in length and several feet in diameter. It is common practice to bore out the center of the shaft to remove flaws in the rotor material. Even after the center of the shaft has been removed, flaws in the steel material near the bore surface may still exist and routine inspections are necessary to determine whether the flaws have expanded due to operating stress and to ensure that the shaft is safe from catastrophic failure.
Immersion type ultrasonic inspection, as practiced in the above-identified U.S. patent applications, requires the use of a liquid such as water as a coupling medium for transmitting ultrasonic pulses from the transducer into the rotor material. Flaws are detected based on reflections of the ultrasonic sound wave from material discontinuities.
A bottle bore shaft is a shaft in which the mid portion has a larger diameter than the end portions. Air can be trapped in the bottle bore portion of the shaft even when the shaft is tilted from a horizontal position. Trapped air reflects and/or diffuses the ultrasonic pulses and the pulse path cannot be reliably determined. Trapped air can prevent the inspection of the portion of the shaft where the air is trapped. For a complete inspection the air must be removed from the shaft.
One method which removes most of the air is described in U.S. Pat. No. 4,670,029 and involves the application of a vacuum to the water filled shaft. Because a perfect vacuum cannot be achieved in the presence of water, about a tenth of the air initially trapped in the bottle bore will remain to form a much smaller air pocket producing a bubble which blocks inspection. FIG. 1 illustrates how a bottle bore 8 can trap air 10 in a water filled 12 shaft 14 even when the shaft 14 is tilted and a vacuum dearation system is used to remove as much air as possible. The water is held in the shaft 14 by an end cap 15.
Another method uses a long small diameter flexible tube at the end of a sensing head to suck the trapped air from the bottle bore. The tube must be attached to a manipulator normally used to position a transducer. This system depends on precise positioning of the tube at the highest point of the surface predicted to harbor the bubble and, since a person cannot actually observe that all the air has been removed, this method does not assure complete removal.
Another much less expensive method uses a flexible vinyl (TYGON) tube attached to the end of a plumbers snake. A small plastic float is attached to the end of a short length of the tube which extends beyond the snake. The snake inserts the tube into the bottle bore where the float lifts the tube into the air pocket where the air is removed by suction. This device is difficult to control and does not assure complete air removal.
SUMMARY OF THE INVENTION
It is an object of the present invention to remove substantially all air trapped in a bottle bore of a turbine or generator shaft.
It is another object of the present invention to provide a simple low cost trapped air removal system.
It is an additional object of the present invention to provide an air removal system that does not require precise placement of the air removal device.
It is a further object of the present invention to provide an air removal system that provides the user with a high confidence level that all trapped air has been removed.
The present invention includes a compliant air filled bladder and a device for inserting the bladder into the bottle bore region of a large turbine or generator shaft. The flexible bladder floats to the top of the bottle bore and displaces the air trapped in the bottle bore region by conforming to the interior surface of the bottle bore. The bladder forces the air down to a position where it will escape to the upper end of the shaft along the slightly tilted interior surface of the shaft. An outer insertion tube is provided for protecting the rather fragile bladder during insertion. The bladder can be inflated by pumping pressurized gas through an inner tube into the bladder. The bladder can also be inflated by sealing a small amount of air in the bladder and inner tube, and then applying a vacuum to the turbine shaft during a vacuum dearation air removal procedure.
These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates how air can be trapped in a rotor shaft 14 even when a vacuum is applied thereto;
FIGS. 2 and 3 illustrate how a compliant bladder 30 will displace air trapped in a bottle bore 8; and
FIG. 4 illustrates one method of coupling the bladder 30 to an air pump 42.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention, as depicted in FIGS. 2 and 3, is an inflatible, compliant bladder 30 attached to a small tube 32 which is used to inflate the bladder 30 while in the bottle bore 8. The bladder 30 is a very compliant substance, such as for example, latex rubber, silicone rubber, polyvinyl or polyethylene film, which will allow the bladder to substantially conform to the interior shape of the bottle bore 8 so that substantially all the air trapped in the bottle bore will be displaced downward under the edge of the bottle bore 8 which along with the angled shaft forms the exit for the displaced gas. The small inner tube 32 is made of plastic such as polyethylene or polyvinyl. This tube 32 must be sufficiently stiff to be able to push the bladder 30 out of the larger outer tube 34 and to also retract the collapsed bladder 30 back into the tube 34, while at the same time being flexible enough to allow the bladder 30 to float to the top of the bottle bore 8. The tube 32 could have a flexible end piece and a rather stiff shaft to allow this dual function to be performed at low cost.
The larger outer tube 34 acts as a protective cover and a stiffening device for insertion of the bladder 30 and should have a length sufficient to reach the bottle bore portion 8 of the shaft 14. A PVC pipe will provide an acceptable light weight outer tube 34.
The bladder 30 is inflated through tube 32 and holes 36 which are positioned inside bladder 30. The bladder 30 is sealed at both ends 38a and 38b to the tube 32 and the tube 32 is also sealed at the far end 38a. The bladder 30 is used most effectively with the vacuum dearation method described in U.S. Pat. No. 4,670,029, and incorporated by reference herein. However, the bladder 30 produces adequate air displacement in the bottle bore 8 when used at atmospheric pressure. It is also possible to inflate the bladder 30 with a light gas such as helium.
When used with the preferred vacuum dearation method, the bladder 30 is inserted in a collapsed condition into the shaft 14 through an adapter 16 which is completely underwater in a water filled tank 40 as illustrated in FIG. 4. The bladder 30 is positioned in the protective tube 34 in a collapsed condition. When the tube 34 has the bladder 30 in the appropriate position the protective tube 34 is retracted to expose the full length of the bladder 30 and a sufficient portion of tube 32 to allow the bladder 30 to float freely when expanded. To properly position the tube 34 in the shaft 14, the tube 34 should be marked with distance measuring graduations so that insertion to the proper position is possible. Once the bladder 30 is in position, a pump 42 can be used to inflate the bladder 30. It is also possible to seal the inner tube 32 at the outer end 44. If the tube 32 is sealed at the outer end 44, it should contain sufficient air to inflate the bladder to an absolute pressure of about 5 inches of mercury when the external pressure in the bore is reduced to about 3 inches of mercury. Since the water 12 filling the bore is at low pressure the inflated bladder 30 will float and displace the air at the top of the bottle bore 8 to cause the air outside the bladder 30 to migrate down to the main level of the bore where it can escape up the tilted shaft 14 and be evacuated from the upper end and out the outlet 15.
It is also possible to position the bladder 30 at the farthest end of the shaft 14 adjacent the end cap 15 and slowly pull it out allowing it to float along the upper surface of the shaft bore. This method is not preferred because it complicates the sealing problem when a vacuum is applied to the shaft 14 but may be adequate without applying a vacuum to the shaft 14.
Since the bladder 30 is made from a very elastic and compliant material it will displace substantially all of the air. If the vacuum dearation method is used, when the bore 8 is returned to atmospheric pressure any very small bubbles which remain will contract to 1/10th of their initial size so that the few tiny remaining bubbles will not adversely affect any ultrasonic inspection. In the vacuum dearation method, as the bore 8 returns to atmospheric pressure and if the sealed end type tube 32 is used, the bladder 30 will contract to its fully collapsed condition so that protective tube 34 can be extended over the bladder 30 and withdrawn without causing damage.
If additional air needs to be removed from the bottle bore 8 the sealed end of the tube 32 can be exposed to atmospheric pressure and the bouyancy of the bladder 30 will be substantially increased thereby further displacing trapped air. It is also possible to produce a positive gas pressure in the bladder 30 by using a pump 42. However, in this method the pressure applied to the bladder 30 should not be excessive since the bladder 30 would rupture. In this method it is also better not to fully inflate the bladder so that it will be more compliant.
If the sealed tube method is used, the amount of air required inside the tube 32 and the bladder 30 can be calculated and permanently sealed therein, since the volume of air required can be determined by the approximate ratio of the pressures and the final required volume is approximately constant. If the air pump method is used an absolute pressure of about 5 inches of mercury in the bladder 30 would be appropriate.
When the present invention is used at atmospheric pressure it should be used after vacuum dearation because it is best to evacuate the bore and remove all air dissolved in the water so that when the invention is inserted and used to remove the trapped air, additional dissolved air will not later rise to the top of the bottle bore 8. In this method the inner tube 32 must be inflated at a pressure of about 3 inches of mercury above atmospheric pressure to displace the air in the bottle bore 8.
It is also possible to inflate the bladder 30 so that it completely fills the shaft at the location of the bottle bore 8. This approach is not recommended because it could prevent the air from migrating up the bore to escape. In addition the bladder 30 thickness would have to be so great that it may not fully conform to the shape of the bottle bore 8, thus allowing trapped air to remain.
The many features and advantages of the present invention are apparent from the detailed specification and thus it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope thereof. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A trapped air displacement device includes a flexible gas fillable bladder 30 and a device 34 for inserting the bladder 30 into a bottle bore 8 of a turbine or generator shaft 14. The flexible bladder 30 displaces the air trapped in the bottle bore region 8, so that it will escape along the slightly tilted surface of the shaft 14. A protective tube 34 is provided for the fragile bladder 30 during positioning. The bladder 30 can be inflated through an inner tube 32. The bladder 30 can also be inflated by sealing a small amount of gas in the bladder 30 and tube 30 and applying a vacuum to the shaft 14. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and incorporates by reference co-pending application Ser. No. 09/376,133, filed Aug. 17,1999, which is a continuation of application Ser. No. 08/232,615, filed Apr. 25,1994, now issued as U.S. Pat. No. 5,980,513, and further incorporates U.S. Pat. Nos. 5,849,006 and 5,632,742 by reference, all of which are commonly owned and have the disclosures incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates generally to laser systems, and more particularly to a laser system used to erode a moving surface such as an eye's corneal tissue.
BACKGROUND OF THE INVENTION
[0003] Use of lasers to erode all or a portion of a workpiece's surface is known in the art. In the field of ophthalmic medicine, photorefractive keratectomy (PRK) is a procedure for laser correction of focusing deficiencies of the eye by modification of corneal curvature. PRK is distinct from the use of laser-based devices for more traditional ophthalmic surgical purposes, such as tissue cutting or thermal coagulation. PRK is generally accomplished by use of a 193 nanometer wavelength excimer laser beam that ablates away the workpiece, i.e., corneal tissue, in a photo decomposition process. Most clinical work to this point has been done with a laser operating at a fluence level of 120-195 mJ/cm 2 and a pulse-repetition rate of approximately 5-10 Hz. The procedure has been referred to as “corneal sculpting.”
[0004] Before sculpting of the cornea takes place, the epithelium or outer layer of the cornea is mechanically removed to expose Bowman's membrane on the anterior surface of the stroma. At this point, laser ablation at Bowman's layer can begin. An excimer laser beam is preferred for this procedure. The beam may be variably masked during the ablation to remove corneal tissue to varying depths as necessary for recontouring the anterior stroma. Afterward, the epithelium rapidly regrows and resurfaces the contoured area, resulting in an optically correct (or much more nearly so) cornea. In some cases, a surface flap of the cornea is folded aside and the exposed surface of the cornea's stroma is ablated to the desired surface shape with the surface flap then being replaced.
[0005] Phototherapeutic keratectomy (PTK) is a procedure involving equipment functionally identical to the equipment required for PRK. The PTK procedure differs from PRK in that rather than reshaping the cornea, PTK uses the aforementioned excimer laser to treat pathological superficial, corneal dystrophies, which might otherwise require corneal transplants.
[0006] In both of these procedures, surgical errors due to application of the treatment laser during unwanted eye movement can degrade the refractive outcome of the surgery. The eye movement or eye positioning is critical since the treatment laser is centered on the patient's theoretical visual axis which, practically-speaking, is approximately the center of the patient's pupil. However, this visual axis is difficult to determine due in part to residual eye movement and involuntary eye movement known as saccadic eye movement. Saccadic eye movement is high-speed movement (i.e., of very short duration, 10-20 milliseconds, and typically up to 1° of eye rotation) inherent in human vision and is used to provide dynamic scene to the retina. Saccadic eye movement, while being small in amplitude, varies greatly from patient to patient due to psychological effects, body chemistry, surgical lighting conditions, etc. Thus, even though a surgeon may be able to recognize some eye movement and can typically inhibit/restart a treatment laser by operation of a manual switch, the surgeon's reaction time is not fast enough to move the treatment laser in correspondence with eye movement.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an object of the present invention to provide a laser beam delivery and eye tracking method and system that is used in conjunction with a laser system capable of eroding a surface.
[0008] Another object of the present invention is to provide a system for delivering a treatment laser to a surface and for automatically redirecting the treatment laser to compensate for movement of the surface.
[0009] Still another object of the present invention is to provide a system for delivering a corneal ablating laser beam to the surface of an eye in a specific pattern about the optical center of the eye, and for automatically redirecting the corneal ablating laser beam to compensate for eye movement such that the resulting ablating pattern is the same regardless of eye movement.
[0010] Yet another object of the present invention is to provide a laser beam delivery and eye tracking system for use with an ophthalmic treatment laser where the tracking operation detects eye movement in a non-intrusive fashion.
[0011] A further object of the present invention is to provide a laser beam delivery and eye tracking system for automatically delivering and maintaining a corneal ablating laser beam with respect to the geometric center of an eye's pupil or a doctor defined offset from the center of the eye's pupil. A special object of this invention is the use of the laser pulses which are distributed in a pattern of discrete ablations to shape objects other than for corneal ablating.
[0012] Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
[0013] In accordance with the present invention, an eye treatment laser beam delivery and eye tracking system is provided. A treatment laser and its projection optics generate laser light along an original beam path (i.e., the optical axis of the system) at an energy level suitable for treating the eye. An optical translator shifts the original beam path in accordance with a specific scanning pattern so that the original beam is shifted onto a resulting beam path that is parallel to the original beam path. An optical angle adjuster changes the resulting beam path's angle relative to the original beam path such that the laser light is incident on the eye.
[0014] An eye movement sensor detects measurable amounts of movement of the eye relative to the system's optical axis and then generates error control signals indicative of the movement. The eye movement sensor includes 1) a light source for generating light energy that is non-damaging with respect to the eye, 2) an optical delivery arrangement for delivering the light energy on a delivery light path to the optical angle adjuster in a parallel relationship with the resulting beam path of the treatment laser, and 3) an optical receiving arrangement. The parallel relationship between the eye movement sensor's delivery light path and the treatment laser's resulting beam path is maintained by the optical angle adjuster. In this way, the treatment laser light and the eye movement sensor's light energy are incident on the eye in their parallel relationship.
[0015] A portion of the eye movement sensor's light energy is reflected from the eye as reflected energy traveling on a reflected light path back through the optical angle adjuster. The optical receiving arrangement detects the reflected energy and generates the error control signals based on the reflected energy. The optical angle adjuster is responsive to the error control signals to change the treatment laser's resulting beam path and the eye movement sensor's delivery light path in correspondence with one another. In this way, the beam originating from the treatment laser and the light energy originating from the eye movement sensor track along with the eye's movement.
[0016] In carrying out this technique, the pattern constitutes overlapping but not coaxial locations for ablation to occur with each pulse removing a microvolume of material by ablation or erosion. For different depths, a pattern is repeated over those areas where increased ablation is needed. The laser pulses are usually at a certain pulse repetition rate. The subsequent pulses in a sequence are spaced at least one pulse beam width from the previous pulse and at a distance the ablated particles will not—substantially interfere with the subsequent pulse. In order to maximize the speed of the ablation, the subsequent pulse is spaced sufficiently close to enable the beam to be moved to the successive location within the time of the pulse repetition. The ablation is carried out on an object until a desired specific shape is achieved.
[0017] This technique is fundamentally new and may be used on objects other than corneas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [0018]FIG. 1 is a block diagram of a laser beam delivery and eye tracking system in accordance with the present invention as it would be used in conjunction with an ophthalmic treatment laser;
[0019] [0019]FIG. 2 is a sectional view of the projection optics used with the ophthalmic treatment laser embodiment of the laser beam delivery portion of the present invention;
[0020] [0020]FIG. 3 illustrates diagrammatically an optical arrangement of mirrors used to produce translational shifts in a light beam along one axis;
[0021] [0021]FIG. 4 is a block diagram of the servo controller/motor driver circuitry used in the ophthalmic treatment laser embodiment of the present invention; and
[0022] [0022]FIG. 5 is a block diagram of a preferred embodiment eye movement sensor used in the ophthalmic treatment laser embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Referring now to the drawings, and more particularly to FIG. 1, a block diagram is shown of a laser beam delivery and eye tracking system referenced generally by the numeral 5 . The laser beam delivery portion of system 5 includes treatment laser source 500 , projection optics 510 , X-Y translation mirror optics 520 , beam translation controller 530 , dichroic beamsplifter 200 , and beam angle adjustment mirror optics 300 . By way of example, it will be assumed that treatment laser 500 is a 193 nanometer wavelength excimer laser used in an ophthalmic PRK (or PTK) procedure performed on a movable workpiece, e.g., eye 10 . However, it is to be understood that the method and system of the present invention will apply equally as well to movable workpieces other than an eye, and further to other wavelength surface treatment or surface eroding lasers. The laser pulses are distributed as shots over the area to be ablated or eroded, preferably in a distributed sequence. A single laser pulse of sufficient power to cause ablation creates a micro cloud of ablated particles which interferes with the next laser pulse if located in the same or immediate point. To avoid this interference, the next laser pulse is spatially distributed to a next point of erosion or ablation that is located a sufficient distance so as to avoid the cloud of ablated particles. Once the cloud is dissipated, another laser pulse is made adjacent the area prior eroded so that after the pattern of shots is completed the cumulative shots fill in and complete said pattern so that the desired shape of the object or cornea is achieved.
[0024] In operation of the beam delivery portion of system 5 , laser source 500 produces laser beam 502 which is incident upon projection optics 510 . Projection optics 510 adjusts the diameter and distance to focus of beam 502 depending on the requirements of the particular procedure being performed. For the illustrative example of an excimer laser used in the PRK or PTK procedure, projection optics 510 includes planar concave lens 512 , and fixed focus lenses 514 and 516 as shown in the sectional view of FIG. 2. Lenses 512 and 514 act together to form an A-focal telescope that expands the diameter of beam 502 . Fixed focus lens 516 focuses the expanded beam 502 at the workpiece, i.e., eye 10 , and provides sufficient depth, indicated by arrow 518 , in the plane of focus of lens 516 . This provides flexibility in the placement of projection optics 510 relative to the surface of the workpiece. An alternative implementation is to eliminate lens 514 when less flexibility can be tolerated.
[0025] After exiting projection optics 510 , beam 502 impinges on X-Y translation mirror optics 520 where beam 502 is translated or shifted independently along each of two orthogonal translation axes as governed by beam translation controller 530 . Controller 530 is typically a processor programmed with a predetermined set of two-dimensional translations or shifts of beam 502 depending on the particular ophthalmic procedure being performed. For the illustrative example of the excimer laser used in a PRK or PTK procedure, controller 530 may be programmed in accordance with the aforementioned copending patent application entitled “Laser Sculpting System and Method”. The programmed shifts of beam 502 are implemented by X-Y translation mirror optics 520 .
[0026] Each X and Y axis of translation is independently controlled by a translating mirror. As shown diagrammatically in FIG. 3, the Y-translation operation of X-Y translation mirror optics 520 is implemented using translating mirror 522 . Translating mirror 522 is movable between the position shown and the position indicated by dotted line 526 . Movement of translating mirror 522 is such that the angle of the output beam with respect to the input beam remains constant. Such movement is brought about by translation mirror motor and control 525 driven by inputs received from beam translation controller 530 . By way of example, motor and control 525 can be realized with a motor from Trilogy Systems Corporation (e.g., model T050) and a control board from Delta Tau Systems (e.g., model 400-602276 PMAC).
[0027] With translating mirror 522 positioned as shown, beam 502 travels the path traced by solid line 528 a . With translating mirror 522 positioned along dotted line 526 , beam 502 travels the path traced by dotted line 528 b . A similar translating mirror (not shown) would be used for the X-translation operation. The X-translation operation is accomplished in the same fashion but is orthogonal to the Y-translation. The X-translation may be implemented prior or subsequent to the Y-translation operation.
[0028] The eye tracking portion of system 5 includes eye movement sensor 100 , dichroic beamsplitter 200 and beam angle adjustment mirror optics 300 . Sensor 100 determines the amount of eye movement and uses same to adjust mirrors 310 and 320 to track along with such eye movement. To do this, sensor 100 first transmits light energy 101 -T which has been selected to transmit through dichroic beamsplifter 200 . At the same time, after undergoing beam translation in accordance with the particular treatment procedure, beam 502 impinges on dichroic beamsplitter 200 which has been selected to reflect beam 502 (e.g., 193 nanometer wavelength laser beam) to beam angle adjustment mirror optics 300 .
[0029] Light energy 101 -T is aligned such that it is parallel to beam 502 as it impinges on beam angle adjustment mirror optics 300 . It is to be understood that the term “parallel” as used herein includes the possibility that light energy 101 -T and beam 502 can be coincident or collinear. Both light energy 101 -T and beam 502 are adjusted in correspondence with one another by optics 300 . Accordingly, light energy 101 -T and beam 502 retain their parallel relationship when they are incident on eye 10 . Since X-Y translation mirror optics 520 shifts the position of beam 502 in translation independently of optics 300 , the parallel relationship between beam 502 and light energy 101 -T is maintained throughout the particular ophthalmic procedure.
[0030] Beam angle adjustment mirror optics consists of independently rotating mirrors 310 and 320 . Mirror 310 is rotatable about axis 312 as indicated by arrow 314 while mirror 320 is rotatable about axis 322 as indicated by arrow 324 . Axes 312 end 322 are orthogonal to one another. In this way, mirror 310 is capable of sweeping light energy 101 -T and beam 502 in a first plane (e.g., elevation) while mirror 320 is-capable of independently sweeping light energy 101 -T and beam 502 in a second plane (e.g., azimuth) that is perpendicular to the first plane. Upon exiting beam angle adjustment mirror optics 300 , light energy 101 -T and beam 502 impinge on eye 10 .
[0031] Movement of mirrors 310 and 320 is typically accomplished with servo controller/motor drivers 316 and 326 , respectively. FIG. 4 is a block diagram of a preferred embodiment servo controller/motor driver 316 used for the illustrative PRK/PTK treatment example. (The same structure is used for servo controller/motor driver 326 .) In general, drivers 316 and 326 must be able to react quickly when the measured error from eye movement sensor 100 is large, and further must provide very high gain from low frequencies (DC) to about 100 radians per second to virtually eliminate both steady state and transient error.
[0032] More specifically, eye movement sensor 100 provides a measure of the error between the center of the pupil (or an offset from the center of the pupil that the doctor selected) and the location where mirror 310 is pointed. Position sensor 3166 is provided to directly measure the position of the drive shaft (not shown) of galvanometer motor 3164 . The output of position sensor 3166 is differentiated at differentiator 3168 to provide the velocity of the drive shaft of motor 3164 .
[0033] This velocity is summed with the error from eye movement sensor 100 . The sum is integrated at integrator 3160 and input to current amplifier 3162 to drive galvanometer motor 3164 . As the drive shaft of motor 3164 rotates mirror 310 , the error that eye movement sensor 100 measures decreases to a negligible amount. The velocity feedback via position sensor 3166 and differentiator 3168 provides servo controller/motor driver 316 with the ability to react quickly when the measured sensor error is large.
[0034] Light energy reflected from eye 10 , as designated by reference numeral 101 -R, travels back through optics 300 and beamsplitter 200 for detection at sensor 100 . Sensor 100 determines the amount of eye movement based on the changes in reflection energy 101 -R. Error control signals indicative of the amount of eye movement are fed back by sensor 100 to beam angle adjustment mirror optics 300 . The error control signals govern the movement or realignment of mirrors 310 and 320 in an effort to drive the error control signals to zero. In doing this, light energy 101 -T and beam 502 are moved in correspondence with eye movement while the actual position of beam 502 relative to the center of the pupil is controlled by X-Y translation mirror optics 520 .
[0035] In order to take advantage of the properties of beamsplitter 200 , light energy 101 -T must be of a different wavelength than that of treatment laser beam 502 . The light energy should preferably lie outside the visible spectrum so as not to interfere or obstruct a surgeon's view of eye 10 . Further, if the present invention is to be used in ophthalmic surgical procedures, light energy 101 -T must be “eye safe” as defined by the American National Standards Institute (ANSI). While a variety of light wavelengths satisfy the above requirements, by way of example, light energy 101 -T is infrared light energy in the 900 nanometer wavelength region. Light in this region meets the above noted criteria and is further produced by readily available, economically affordable light sources. One such light source is a high pulse repetition rate GaAs 905 nanometer laser operating at 4 kHz which produces an ANSI defined eye safe pulse of 10 nanojoules in a 50 nanosecond pulse.
[0036] A preferred embodiment method for determining the amount of eye movement, as well as eye movement sensor 100 for carrying out such a method, are described in detail in the aforementioned copending patent application. However, for purpose of a complete description, sensor 100 will be described briefly with the aid of the block diagram shown in FIG. 2. Sensor 100 may be broken down into a delivery portion and a receiving portion. Essentially, the delivery portion projects light energy 101 -T in the form of light spots 21 , 22 , 23 and 24 onto a boundary (e.g., iris/pupil boundary 14 ) on the surface of eye 10 . The receiving portion monitors light energy 101 -R in the form of reflections caused by light spots 21 , 22 , 23 and 24 .
[0037] In delivery, spots 21 and 23 are focused and positioned on axis 25 while spots 22 and 24 are focused and positioned on axis 26 as shown. Axes 25 and 26 are orthogonal to one another. Spots 21 , 22 , 23 and 24 are focused to be incident on and evenly spaced about iris/pupil boundary 14 . The four spots 21 , 22 , 23 and 24 are of equal energy and are spaced evenly about and on iris/pupil boundary 14 . This placement provides for two-axis motion sensing in the following manner. Each light spot 21 , 22 , 23 and 24 causes a certain amount of reflection at its position on iris/pupil boundary 14 . Since boundary 14 moves in coincidence with eye movement, the amount of reflection from light spots 21 , 22 , 23 and 24 changes in accordance with eye movement. By spacing the four spots evenly about the circular boundary geometry, horizontal or vertical eye movement is detected by changes in the amount of reflection from adjacent pairs of spots. For example, horizontal eye movement is monitored by comparing the combined reflection from light spots 21 and 24 with the combined reflection from light spots 22 and 23 . In a similar fashion, vertical eye movement is monitored by comparing the combined reflection from light spots 21 and 22 with the combined reflection from light spots 23 and 24 .
[0038] More specifically, the delivery portion includes a 905 nanometer pulsed diode laser 102 transmitting light through optical fiber 104 to an optical fiber assembly 105 that splits and delays each pulse from laser 102 into preferably four equal energy pulses. Assembly 105 includes one-to-four optical splitter 106 that outputs four pulses of equal energy into optical fibers 108 , 110 , 112 , 114 . In order to use a single processor to process the reflections caused by each pulse transmitted by fibers 108 , 110 , 112 and 114 , each pulse is uniquely delayed by a respective fiber optic delay line 109 , 111 , 113 and 1 15 . For example, delay line 109 causes a delay of zero, i.e., DELAY=Ox where x is the delay increment; delay line 111 causes a delay of x, i.e., DELAY=lx; etc.
[0039] The pulse repetition frequency and delay increment x are chosen so that the data rate of sensor 100 is greater than the speed of the movement of interest. In terms of saccadic eye movement, the data rate of sensor 100 must be on the order of at least several hundred hertz. For example, a sensor data rate of approximately 4 kHz is achieved by 1) selecting a small but sufficient value for x to allow processor 160 to handle the data (e.g., 160 nanoseconds), and 2) selecting the time between pulses from laser 102 to be 250 microseconds (i.e., laser 102 is pulsed at a 4 kHz rate).
[0040] The four equal energy pulses exit assembly 105 via optical fibers 116 , 118 , 120 and 122 which are configured as a fiber optic bundle 123 . Bundle 123 arranges the optical fibers such that the center of each fiber forms the corner of a square. Light from assembly 105 is passed through an optical polarizer 124 that outputs horizontally polarized light beams as indicated by arrow 126 . Horizontally polarized light beams 126 pass to focusing optics 130 where spacing between beams 126 is adjusted based on the boundary of interest. Additionally, a zoom capability (not shown) can be provided to allow for adjustment of the size of the pattern formed by spots 21 , 22 , 23 and 24 . This capability allows sensor 100 to adapt to different patients, boundaries, etc.
[0041] A polarizing beam splitting cube 140 receives horizontally polarized light beams 126 from focusing optics 130 . Cube 140 is configured to transmit horizontal polarization and reflect vertical polarization. Accordingly, cube 140 transmits only horizontally polarized light beams 126 as indicated by arrow 142 . Thus, it is only horizontally polarized light that is incident on eye 10 as spots 21 , 22 , 23 and 24 . Upon reflection from eye 10 , the light energy is depolarized (i.e., it has both horizontal and vertical polarization components) as indicated by crossed arrows 150 .
[0042] The receiving portion first directs the vertical component of the reflected light as indicated by arrow 152 . Thus, cube 140 serves to separate the transmitted light energy from the reflected light energy for accurate measurement. The vertically polarized portion of the reflection from spots 21 , 22 , 23 and 24 , is passed through focusing lens 154 for imaging onto an infrared detector 156 . Detector 156 passes its signal to a multiplexing peak detecting circuit 158 which is essentially a plurality of peak sample and hold circuits, a variety of which are well known in the art. Circuit 158 is configured to sample (and hold the peak value from) detector 156 in accordance with the pulse repetition frequency of laser 102 and the delay x. For example, if the pulse repetition frequency of laser 102 is 4 kHz, circuit 158 gathers reflections from spots 21 , 22 , 23 and 24 every 250 microseconds.
[0043] The values associated with the reflected energy for each group of four spots (i.e., each pulse of laser 102 ) are passed to a processor 160 where horizontal and vertical components of eye movement are determined. For example let R21, R22, R23 and R24 represent the detected amount of reflection from one group of spots 21 , 22 , 23 and 24 , respectively. A quantitative amount of horizontal movement is determined directly from the normalized relationship
( R 21 + R 24 ) - ( R 22 - R 23 ) R 21 + R 22 + R 23 + R 24
[0044] while a quantitative amount of vertical movement is determined directly from the normalized relationship
( R 21 + R 22 ) - ( R 23 - R 24 ) R 21 + R 22 + R 23 + R 24
[0045] Note that normalizing (i.e., dividing by R 21 +R 22 +R 23 +R 24 ) reduces the effects of variations in signal strength. Once determined, the measured amounts of eye movement are sent to beam angle adjustment mirror optics 300 .
[0046] The advantages of the present invention are numerous. Eye movement is measured quantitatively and used to automatically redirect both the laser delivery and eye tracking portions of the system independent of the laser positioning mechanism. The system operates without interfering with the particular treatment laser or the surgeon performing the eye treatment procedure.
[0047] Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described. | An ophthalmic laser system includes a laser beam delivery system and an eye tracker responsive to movement of the eye operable with a laser beam delivery system for ablating corneal material of the eye through placement of laser beam shot on a selected area of the cornea of the eye. The shots are fired in a sequence and pattern such that no laser shots are fired at consecutive locations and no consecutive shots overlap. The pattern is moved in response to the movement of the eye. | 0 |
RELATED APPLICATIONS
This application is claims priority to U.S. Provisional Patent Application Ser. No. 61/387,935, filed Sep. 29, 2010 the contents of which are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
Irradiation is a common method used for sterilizing objects in the food, medical, and entomology fields. Food irradiation reduces bacterial load, preventing foodborne illness. Irradiation of insects for use in Sterile Insect Technique (SIT) for suppression of native populations or invasive species is widespread. Irradiation is also used for a number of medical procedures. Insects are sterilized through irradiation and released into the wild to sexually compete with the population at large, thus reducing the chance for reproduction. Traditionally, irradiation sources are comprised of radioisotopes such as Cobalt. However, the use of radioisotopes is unpopular with the general population and access has become increasingly limited due to security issues. Consequently, efforts have been made to develop x-ray technology to replace radioisotopes for this purpose. Due to the heavy radiation dose required, these x-ray units are often comprised of high energy (450 kV) x-ray sources mounted in large cabinets. Whether irradiation is done with isotopes or x-ray sources, non-uniformity of the delivered dose has been a consistent problem. This, combined with the high cost of traditional irradiation equipment (in either form) has hindered the widespread use of SIT. Reported here is an irradiation technique using x-ray technology that uses multiple x-ray sources in a configuration that delivers a more uniform dose while providing equal throughput to the high power units at a significantly lower cost.
SUMMARY OF THE INVENTION
An embodiment of the invention is an apparatus utilizing x-ray tubes surrounding a cylinder containing insects targeted for sterilization wherein the cylinder is at an optimized distance and moves at a fixed rate along the direction perpendicular to the plane containing the four x-ray sources.
A further embodiment of the invention is a method of sterilizing insects with said apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a graph of the estimated dose as a function of distance from the anode of a 110 kV x-ray tube.
FIG. 2 shows a plot of the absorption coefficient derived for the Light Brown Apple Moth (LBAM).
FIG. 3 shows a dose attenuation due to distance from the anode, LBAM absorption and total combined effect.
FIG. 4 illustrates calculated dose distributions based on distance attenuation through a horizontal slice of a cylinder for one, two, and four x-ray tubes.
FIG. 5 is a drawing of four x-ray tubes with overlapping target areas or beams. The sample container moves vertically through an X-ray irradiation zone to receive a uniform dose. Rotation of the sample container could be incorporated to provide even more uniformity.
a. DEFINITIONS
“SIT” means sterile insect technique wherein affected insects are infertile.
“Cylinder” means a solid of circular cross section in which the centers of the circles all lie on a single line, wherein the cross sections lie directly on top of each other. The term is inclusive of right circular cylinders.
“Plurality” means two or more x ray sources utilized for the sterilization technique.
X-ray absorption coefficient refers to a measure of the ability of a material to absorb x-rays.
“Insects” means all members of the Orders Lepidoptera and Diptera.
DETAILED DESCRIPTION OF THE INVENTION
An irradiation system using soft x-rays was developed for sterilization of insects for SIT. Using multiple x-ray tubes and minimizing source to insect distance allowed for the use of much lower x-ray energies than equipment that is currently available. In addition, the multiple tube design allows for a more uniform dose distribution within the container than has been accomplished using single point sources. The reduced x-ray energy requirement allows for the use of relatively inexpensive commercially available x-ray sources, making the system more economical than traditional methods. By surrounding a sample with a number n of x-ray sources: Sources currently in use in SIT include radioisotopes, high-energy electrons, and x-rays. Traditionally, SIT programs use gamma radiation sources, such as Cobalt60 and Cesium137, for development of isotopic irradiators to sterilize insects. These irradiators completely contain the radioisotopes and direct gamma rays toward a sample through a guided opening. Other alternatives to isotopic irradiators include high-energy electrons (with energy <10 MeV) and X rays (from electron beams with energies below 7.5 MeV), both of which require high voltage power sources. Reference: T. Mastrangelo, A. G. Parker, A. Jessup, R. Pereira, D. Orozco-Davila, A. Islam, T. Dammalage, and J. M. M. Walder. A New Generation of X Ray Irradiators for Insect Sterilization. Journal of Economic Entomology 103(1):85-94. 2010.
By surrounding a sample with a plurality of x-ray sources a higher applied dose may be achieved over single source x ray sources. A single source x ray system will have an upper limit of power and corresponding dose able to be applied and a limited amount of space to fit samples to rotate around it, whereas multiple x-ray sources around a sample theoretically provide many times the power and corresponding dose to a sample area. Additionally the plural x ray source described herein achieves a relatively uniform dose (see FIG. 4 ) of theoretical dose from four x-ray tubes) without the aid of moving parts. A minimum of two x-ray sources may be employed; however, four or more is preferred. This is beneficial when used in applications such as sterile insect technique (SIT) in which insect scales and parts eventually cover surfaces of the sample chamber and could possibly interfere with moving parts.
Insects are placed in a container similar to conventional methods using a material with limited x-ray absorbance as to pass as much dose as possible to the sample. Some examples herein incorporated by reference are: canisters of various materials (corrugated plastic tubing, cardboard, and aluminum), 20.3 cm long, various diameters (7.62 cm, 10.2 cm). Reference: Jennifer Koop Wagner, Jeff A. Dillon, Eugene K. Blythec, John R. Forda. Dose characterization of the rad Source™ 2400×-ray irradiator for oyster pasteurization, Applied Radiation and Isotopes , Volume 67, Issue 2, February 2009, Pages 334-339; plastic tubes (90 mm in height by 25 mm in diameter). Reference: T. Mastrangelo, A. G. Parker, A. Jessup, R. Pereira, D. Orozco-Dávila, A. Islam, T. Dammalage, and J. M. M. Walder. A New Generation of X Ray Irradiators for Insect Sterilization. Journal of Economic Entomology 103(1):85-94. 2010. The container may be of any desired geometric shape and volume, such as sphere, prism, cube or cylinder; however, a cylindrical container is preferred. Referring to FIG. 5 , X-ray tubes (1) surround the cylinder (3) at an optimized distance so that the fan shaped beams (2) coming from the source cover the diameter of the circle. This results in a much more uniform dose through any cross section of the cylinder compared to the case of a single source. To allow for large samples and/or to increase throughput, the cylinder can move at a fixed rate along the direction perpendicular to the plane containing two or more x-ray sources, preferably four or more, providing the capability to sterilize insects with comparable throughput rates to the high power commercially available systems, with a more uniform applied dose and significantly reduced cost. The advantages associated with the technique include multiple irradiation sources for higher dose uniformity, multiple irradiation sources for rapid dose administration, strategically placed irradiation source(s) for real time irradiation and streamlining SIT systems by elimination of a separate sterilization step, by irradiation of insects in transit from hatching to collection in the breeding facility.
Sterile insect technique requires a particular dose to be achieved in order to sterilize an insect while also not applying too much dose so that it still appears to function normally in the wild. A typical, perhaps on the high end, dose used to sterilize moths is 350 Gy. Table 1 shows the typical dose from a 110 kV x-ray tube (Source is Faxitron users manual). A moth directly on the anode would receive 350 Gy in 41 seconds (1 Gy=100 R). Dose rises as kV 5/2 , so with a 400 kV x-ray tube it would take around 2.5 sec to reach 350 Gy.
TABLE 1
Typical dose output of a 110 kV x-ray tube.
Voltage (kV)
Distance from anode (cm)
R/min (Gy/min)
110
0
51000 (510)
110
30.48
300 (3.00)
110
63.5
70 (0.70)
Dose declines as a function of the square of the distance from the source (1/x 2 ), therefore the data from Table 1 can be used to generate the graph of FIG. 1 . At around 8 cm, the dose is about 7000 R/min (70 Gy/min). If four x-ray tubes were used simultaneously the collective dose would be increased to 280 Gy/min and 350 Gy could be achieved within 1.25 min. This compares to typical dose rates of 0.02 to 50 Gy/min (17500 to 7 min for 350 Gy) of existing commercial irradiators. The actual distance used would be optimized to maximize insect throughput by taking into account the dose rate of the x-ray tubes, the target angle of the x-ray tubes, and the density of the insects to be sterilized.
While time to achieve the required dose is a major advantage of using multiple x-ray tubes, the uniform dose distribution is also far superior to single point sources. The distribution is a consequence of distance from the anodes and attenuation by the moths. FIG. 2 shows the absorption coefficient derived for the Light Brown Apple Moth (LBAM). FIG. 3 compares attenuation from the moth with loss in intensity due to distance from the anode, with distance being the dominant factor over effects from LBAM density.
FIG. 4 shows the calculated dose distributions (based on distance attenuation) through a horizontal slice of a cylinder for one, two, and four x-ray tubes. Non-uniformity of single point irradiation sources is a consequence of the fact that the delivered dose declines as a function of the square of the distance from the source. By arranging sources concentrically around the sample, the uniformity of the dose obviously increases as the number of tubes increases. An embodiment of the irradiation system employs a sample container that would move vertically at a constant rate through the uniformly irradiated zone so that each circular cross section receives the same dose. A further embodiment is an increase in the uniformity of the dose by rotating the sample container while moving vertical through the irradiation zone.
Multiple tubes with uniform dose distribution and rapid dose rate also introduce the concept of real-time irradiation to SIT. This streamlines SIT facilities by removing the separate process of sterilization from hatching/collection. Instead, insects could be sterilized at some point during the breeding stages, such as when they are transported from the hatching area to the collection area. Multiple sources could easily be placed around the tube in which the insects are being transported. Sources or even a single high power source could be strategically placed so that insects are exposed to irradiation for the appropriate amount of time to achieve a required dose. Target angles of sources could be varied as needed, with large target angles allowing for a longer stretch of transport area to be irradiated. One issue with real-time irradiation could be power consumption if the system was on full time. This could be remedied by a trigger when moths are detected or some other similar adjustment to use power only when needed.
Methods and Materials
The irradiation system consisted of four 100 kV, 1000 W x-ray tubes (CXR-105, Comet North America, Stamford, Conn.) arranged concentrically around a sample area to be irradiated. The x-ray tubes were positioned at a distance to maximize insect throughput while minimizing the time to achieve the required dose. Based on the estimated dose rate of the x-ray tubes, the target angle of the x-ray tubes, and the density of the moths, the optimum distance from the source to the center of the sample was approximately 11.0 cm. This distance was optimum for a sample area and corresponding container of about 8 cm diameter and 8 cm height. For large sample volumes a cylindrical sample container would maintain the optimum diameter for a uniform dose rate and maximum throughput, but could vary in height. To compensate for the decrease in dose along its axis, the cylinder would move at a fixed rate along the direction perpendicular to the plane containing the four x-ray sources. This vertical movement could be done with an electric, hydraulic, or other type of actuator; conveyor; pulley; or any other system to move a sample container through an irradiated area. For an even more uniform dose, the sample container could rotate while moving vertically through the irradiation zone. Rotation could be achieved by mounting this movement system onto a rotating motor, rotating an actuator system via threaded parts, or other means of rotating objects.
The x-ray tubes and sample area were housed in a shielded cabinet lined with lead at least 0.125 inches thick on all sides, top, bottom, and door face. The cabinet included a door face with a step down notch design seated inside the frame, and a shielded port hole for power cables and cooling hoses. X-ray tubes were powered with 100 kV, 1000 W high voltage power supplies (XPg-100N10, Matsusada Precision Inc., San Jose, Calif.). Each x-ray tube had a corresponding power supply, though an ideal system would need only one power supply for all x-ray tubes. Power supplies were interlocked using magnetic switches on the door and body of the cabinet, to automatically cut power if the door was opened. X-ray tubes were water-cooled using a chiller (M1-1.5 A, Advantage Engineering, Greenwood, Ind.). A single hose led to and from the chiller, with a manifold system inside the cabinet to provide coolant to the individual x-ray tubes. | An apparatus and method for sterile insect technique comprising a plurality of x-ray sources surrounding a container containing insects targeted for reproductive sterilization, wherein the container is at an optimized distance from the x-ray sources, moves at a fixed rate along a direction perpendicular to a plane intersecting the x-ray sources, and rotates about an axis parallel to the longitudinal axes of said x-ray sources. | 0 |
TECHNICAL FIELD OF INVENTION
[0001] This invention relates to a nozzle arrangement for a gas turbine engine. In particular, the invention relates to a nozzle arrangement which is adjustable to provide different nozzle areas.
BACKGROUND OF INVENTION
[0002] Gas turbine engines are well known in the art. FIG. 1 shows a known ducted fan gas turbine engine 10 having a principal axis of rotation 11 and comprising, in axial flow series: an air intake 12 , a propulsive fan 14 , an intermediate pressure compressor 16 , a high-pressure compressor 18 , a combustor 20 , a high-pressure turbine 22 , an intermediate pressure turbine 24 , a low-pressure turbine 26 and a core exhaust nozzle 28 . A nacelle 30 generally surrounds the engine 10 and defines the intake 12 , a bypass duct 32 and a bypass exhaust nozzle 34 . It may also include a thrust reverser 36 .
[0003] Air entering the intake 12 is accelerated by the fan 14 to produce a bypass flow and a core flow. The bypass flow travels down the bypass duct and exits the bypass exhaust nozzle to provide the majority of the propulsive thrust produced by the engine 10 . The core flow enters in series the intermediate pressure compressor 16 , high pressure compressor 18 and the combustor 20 , where fuel is added to the compressed air and the mixture burned. The hot combustion products expand through and drive the high, intermediate and low-pressure turbines 22 , 24 , 26 before being exhausted through the nozzle 28 to provide additional propulsive thrust. The high, intermediate and low-pressure turbines 22 , 24 , 26 respectively drive the high and intermediate pressure compressors 18 , 16 and the fan 14 by suitable interconnecting shafts.
[0004] If the bypass or cold nozzle 34 is upstream of the core exhaust or hot nozzle 28 then the engine may be referred to as having separate jets. If the bypass exhaust nozzle 34 extends aft of the core exhaust nozzle 28 and encloses it, then the engine 10 is said to have a mixed exhaust. In that case the bypass or final nozzle is often referred to as a mixed or common nozzle.
[0005] Variable area mixed flow exhaust nozzles are widely used on military turbofan engines. Most variable area cold nozzle designs work by varying the outside diameter of the nozzle, but some designs change the inside diameter of the nozzle by means of a variable geometry afterbody as described for example in the U.S. Pat. No. 3,756,026.
[0006] The benefit of having a variable area cold nozzle is for controlling the working line of the fan for improved fan efficiency, surge margin and operability particularly in turbofan engines with low pressure ratio fans or reheat systems.
[0007] The working line is the locus of fan pressure ratio plotted against fan inlet non-dimensional flow (or mass flow corrected to standard pressure and temperature) for normal steady-state engine operation. At any non-dimensional inlet flow there is an optimum fan pressure ratio for highest efficiency and an upper limit for fan pressure ratio, beyond which the streamline flow through the fan will break down and the fan will surge. At all conditions the non-dimensional flows are determined by the effective fan nozzle exit area and nozzle pressure ratio.
[0008] When the fan pressure ratio is high or the engine is flying at high subsonic (or supersonic) Mach number, the final nozzle will have sonic or near sonic flow and is said to be choked. Under these conditions the fan will have a steep working line which will tend to track the locus of peak fan efficiency and run parallel to the surge line as power is varied, providing a safe margin with respect to surge. However, if the fan pressure ratio and the airspeed are lower, the flow through the nozzle will be subsonic and the non-dimensional flow through the nozzle will reduce with reducing fan power and fan and nozzle pressure ratios.
[0009] In this case the non-dimensional mass flow at entry to the fan will reduce more rapidly as fan speed and power are reduced and so the fan working line will be flatter. This means that the working line no longer follows the locus of peak efficiency and could be too high at low power conditions where the fan may now surge. Conversely, if a larger fan exit nozzle area is provided, the fan efficiency will suffer when the engine is operated at high airspeeds, such as at cruise at altitude, because here the working line will be too low. These problems become more severe as a fan is designed for lower pressure ratios, below about 1.45, and in this case a variable area nozzle can significantly improve fan efficiency at cruise and top of climb conditions.
[0010] An alternative design using a mixed-flow final nozzle of fixed geometry to improve the fan working line is used on several Rolls-Royce engines such as the Trent 700 . In this arrangement the core exhaust and the fan bypass section exhaust are admitted into a common duct and share a common final exhaust nozzle. As the engine is throttled back the core exhaust mass flow reduces more rapidly than the fan bypass section mass flow and occupies a smaller proportion of the final nozzle cross-section, increasing the effective flow area available to the fan bypass flow. This arrangement is helpful, but ultimately not as effective as a variable area nozzle, because it mostly only responds to changes in fan pressure ratio or power level and not to changes in flight speed.
[0011] U.S. Pat. No. 6,070,407 describes a bypass duct of a gas turbine engine which is provided with a secondary duct at least partly within the downstream end of the bypass duct. The secondary duct is provided with means such as flaps whereby the airflow therethrough may be varied to suit the flight requirements of an associated aircraft, in a way which will control the maximum diameter of the free stream tube airflow at the intake of the engine, thus effectively reducing the frontal area of the fan duct, and therefore, drag.
[0012] A similar arrangement to that described in U.S. Pat. No. 6,070,407 is described in US2008302083, but for an entirely separate purpose. Here, the described aircraft has at least one turbofan engine assembly having a shrouded core engine, a short outer nacelle surrounding a fan and a forward portion of the core engine, and a fan exhaust duct through the nacelle. A mixer duct shell is positioned coaxially with the engine shroud and extends forwardly into the fan duct to provide an interstitial mixer duct between the mixer duct shell and the core engine shroud. The aft portion of the mixer duct shell extends over a turbine exhaust frame, an attached mixer (if included), and a tail cone exhaust plug. The mixer duct shell is described as reducing noise and plume exhaust heat radiated from aircraft turbofan engines.
[0013] A forward portion of the shell in US′ 083 is affixed to the core engine shroud by a plurality of circumferentially spaced and aerodynamically tailored radial pillars. An aft portion of the shell may be moved in an aft-ward direction along a pillar slide with weight supported on a sliding track attached to the engine pylon sidewall. Moving the aft portion provides access to underlying structure and is carried out only whilst the engine is not operating. When operating, the aft portion is locked to the core engine in a fixed relation.
[0014] GB1207194 describes a jet engine arranged for the suppression of jet sound and comprises nacelle surrounding a duct for exhaust gas flow; flaps positioned to form a converging section adjacent the end of the duct; blow-in doors pivotally mounted at the end of the nacelle arranged to move inwardly; an annular body positioned rearwardly of the pod or nacelle with the inner surface of the body forming an inlet passageway with each blow-in door, and turbulence inducing means to produce a shear layer surrounding the expanding exhaust flow.
[0015] The present invention seeks to provide an improved variable area nozzle arrangement for a gas turbine engine.
STATEMENTS OF INVENTION
[0016] In a first aspect, the present invention provides a gas turbine engine comprising: a bypass duct having a bypass nozzle; an engine core having a core nozzle; and, a mixer duct having a mixer duct inlet and a mixer nozzle defined by a mixer fairing which is movably mounted to the engine and, wherein the mixer duct is arranged to receive an airflow from the bypass duct through the mixer duct inlet and an airflow from the engine core, when in use, and the geometry of the mixer duct is selectively adjustable by moving the mixer fairing relative to the bypass duct and engine core in use.
[0017] The mixer fairing may be moved between a first position and second position which simultaneously alters one or more of: an output flow area of the bypass nozzle, an output flow area of the mixer nozzle, and, a throat area of the mixer duct inlet. Moving the mixer fairing between the first and second position may simultaneously alter all of: the output flow area of the bypass nozzle, the output flow area of the mixer nozzle, and, the throat area of the mixer duct inlet.
[0018] Moving the mixer fairing between a first and second position may alter the output flow area of the mixer nozzle and moving the mixer fairing between a second and third position may alter the output flow area of the bypass nozzle. Moving the mixer fairing between the second and third positions may additionally alter the mixer duct inlet flow area. A portion of radially outer wall of the mixer fairing downstream of the leading edge may be substantially parallel to the axis of movement such that moving the mixer fairing between a first and second position alters the output flow area of the mixer nozzle and moving the mixer fairing between a second and third position alters the output flow area of the bypass nozzle and mixer nozzle.
[0019] The mixer fairing may be axially translatable relative to the principal axis of the gas turbine engine so as to alter the geometry of the mixer duct.
[0020] The gas turbine engine may further comprise a tail cone. The position of the tail cone may be selectively adjustable relative to the engine core. The tail cone may be movable in an axial direction relative to the principal axis of the engine. The tail cone may be mounted to the engine core. The mounting may be telescopic.
[0021] The position of the tail cone may be selectively adjustable independently of the mixer fairing. Adjusting the tail cone may alter the output flow area of the mixer nozzle only.
[0022] The mixer duct fairing may be substantially annular and generally convergent towards the principal rotational axis of the gas turbine engine.
[0023] The engine core nozzle may exit directly into the mixer duct. Thus, the engine core nozzle may be radially inboard of the mixer fairing.
[0024] The leading edge of the mixer fairing may be at least partially located within the bypass duct in the first and second positions.
[0025] Either or both of the mixer fairing and the trailing edge of the core fairing may include lobes to aid mixing of the engine core airflow and bypass airflow.
[0026] The mixer fairing and tail cone may be configured to move simultaneously. The mixer fairing and tail cone may be movable at different relative speeds. The simultaneous adjustment of the mixer fairing and tail cone may be geared.
[0027] The mixer fairing may be mounted to the gas turbine engine via the tail cone. Alternatively or additionally, the mixer fairing is mounted on a pylon which is attached to the wing or airframe of an aircraft.
[0028] A portion of the mixer duct may be defined by the tail cone and the mixer duct fairing which may be arranged to have a chute therebetween. The minimum flow area of chute may be adjustable with the movement of the mixer fairing.
[0029] The mixer fairing may include a heat exchanger.
[0030] The gas turbine engine may further comprise a thrust reverser having at least one door which is operable to substantially block the bypass duct in a thrust reversing operation. The door may include at least one aperture in an upstream flow path relative to the leading edge of the mixer fairing such that a leading edge of the mixer fairing is provided with a cooling air flow when the thrust reverser door is deployed.
[0031] The gas turbine engine may further comprise a thrust measurement system and at least one sensor operably connected to the thrust measurement system. The sensor is configured to provide the system with a signal which is representative of the position of the mixer fairing and the thrust system determines the engine thrust using the position of the mixer fairing. It will be appreciated that the thrust measurement system may receive other sensor inputs as known in the art in order to determine the engine thrust. Alternatively, or in addition, the thrust measurement system may use the commanded position of the mixer fairing together with other inputs to determine the thrust level of the engine.
[0032] The gas turbine engine may further comprise a tail cone position sensor. The thrust measurement system may determine the engine thrust using the position of either or both the mixer fairing and tail cone. It will be appreciated that the thrust measurement system may receive other sensor inputs as known in the art in order to determine the engine thrust. Alternatively, or in addition, the thrust measurement system may use the commanded position of the mixer fairing, or the tail cone, or both, together with other inputs to determine the thrust level of the engine.
[0033] The thrust measurement system may provide an indication of the engine thrust to the flight deck instrumentation, or to a flight management system, or as feedback to the engine control system, or to any combination of these systems. The thrust measurement processor may be integrated into either or both of the flight management system and the engine control system.
[0034] In a second aspect, the present invention provides a method of operating a gas turbine engine, the gas turbine having a bypass duct having a bypass nozzle; an engine core having a core nozzle; and, a mixer duct defined by a mixer fairing and having a mixer nozzle, wherein the mixer duct is arranged to receive an airflow from the bypass duct through a mixer duct inlet and an airflow from the engine core, when in use, and the geometry of the mixer duct is selectively adjustable by moving the mixer fairing relative to the bypass duct and engine core, the method comprising the steps of: monitoring at least one operating condition of the gas turbine engine; and, adjusting the position of the mixer fairing from a first position to a second position relative to the bypass duct and engine core in response to the monitored engine condition.
[0035] Adjusting the position of the mixer fairing may alter one or more of: an output flow area of the bypass nozzle, an output flow area of the mixer nozzle, and, a throat area of the mixer duct inlet.
[0036] The method of the second aspect may further comprise adjusting the position of the mixer fairing from the first position to the second position in which the output flow area of the bypass nozzle is substantially the same, and between the second position and a third position so as to alter the output flow area of the bypass nozzle.
[0037] The gas turbine engine may include a tail cone, wherein the position of the tail cone is selectively adjustable relative to the engine core in which case the method may further comprise the step of: moving the tail cone relative to the engine core.
[0038] The method of the second aspect may further comprise a thrust measurement system and at least one sensor operably connected to the thrust measurement system, wherein the sensor is configured to provide the thrust measurement system with a signal which is representative of the position of the mixer fairing and the thrust measurement system is configured to determine the engine thrust using the position of the mixer fairing together with other sensor inputs.
[0039] The method of the second aspect may further comprise a thrust reverser having at least one door which is operable to substantially block the bypass duct in a thrust reversing operation, wherein the door includes at least one aperture in an upstream flow path relative to the leading edge of the mixer fairing such that a leading edge of the mixer fairing is provided with a cooling air flow when the thrust reverser door is deployed, the method comprising the steps of: deploying the thrust reverser door to a deployed position; moving the mixer fairing to an aftmost position.
[0040] The method may further comprise the step of moving the tail cone to a foremost position.
[0041] The following drawings are provided to help describe the invention.
DESCRIPTION OF DRAWINGS
[0042] FIG. 1 shows a schematic cross-section through a prior-art ducted fan gas turbine engine.
[0043] FIG. 2 shows a schematic partial cross-section through a gas turbine engine according to the present invention.
[0044] FIG. 3 shows a schematic view from aft on to an engine similar to that shown in FIG. 2 .
[0045] FIG. 4 shows a schematic cross-section through a first gas turbine engine, showing translating exhaust nozzle components deployed in two different positions.
[0046] FIG. 5 shows a schematic cross-section through a second gas turbine engine, showing translating exhaust nozzle components deployed in two different positions.
[0047] FIG. 6 shows a schematic cross-section through a third gas turbine engine, showing translating exhaust nozzle components deployed in two different positions.
[0048] FIG. 7 shows a schematic cross-section through a fourth gas turbine engine, showing translating exhaust nozzle components deployed in two different positions.
[0049] FIG. 8 shows a schematic cross-section through a fifth gas turbine engine, showing exhaust nozzle components and a deployed cascade type thrust reverser.
[0050] FIG. 9 shows a simplified schematic diagram of thrust measurement and control apparatus for use with the translating exhaust nozzle components.
DETAILED DESCRIPTION OF INVENTION
[0051] FIG. 2 shows a partial cross section of a gas turbine engine 210 according to the present invention. The gas turbine is similar to the prior art gas turbine engine 10 shown in FIG. 1 in that it includes an engine core 212 having a core nozzle 214 and a nacelle 216 defining a bypass duct 218 which terminates in a bypass nozzle 220 . The basic operating principle is the same as that of the engine described above in relation to FIG. 1 in that an air flow is created in the bypass duct 218 and exhausted out of the bypass nozzle 220 , and hot gases from the engine core 212 are exhausted from the core nozzle 214 .
[0052] In addition to the prior art engine, there is also included a mixer duct 222 having a mixer nozzle 224 . The mixer duct 222 is configured to receive airflows from the bypass duct 218 and from the engine core nozzle 214 . The two streams of air are mixed within the mixer duct 222 and exhausted via the mixer nozzle 224 to provide propulsive thrust. The nozzles are substantially axi-symmetric about the principal axis 211 of the engine with the exception of a support structure which is described in more detail below.
[0053] The mixer duct 222 is an annular channel defined by a portion 246 of the core exhaust nozzle plug 240 and the inner annulus 234 of the mixer fairing 228 . The mixer fairing 228 includes a relatively broad leading edge 230 and a fine trailing edge 232 with radially inner 234 and outer 237 walls extending therebetween so as to define an aerofoil-like shape in the cross section. This shape has a curved longitudinal axis 238 defined between the leading and trailing edges, which is generally convergent towards the centre line 211 of the engine 210 in the flow direction. In other words, the trailing edge 232 of the mixer annulus is radially inwards of the leading edge 230 with respect to the principal axis 211 of the engine.
[0054] The leading edge 230 of the mixer fairing 228 is located upstream of the bypass nozzle 220 such that the mixer fairing 228 is located partially within the bypass duct 218 . The trailing edge 232 is downstream of the bypass nozzle 220 and is held in a radially spaced relation from a convergent trailing portion 242 of a telescopic tail-cone 240 which is located at the rear of the engine core 212 (and described further below). The space between the trailing edge 232 of the mixer fairing 228 and the tail-cone 240 defines the mixer nozzle 224 from which the mixed bypass air and core exhaust gas is exhausted to provide a propulsive thrust.
[0055] The mixer fairing 228 is mounted to the engine 210 such that it can be axially translated between a first position and a second position relative to the nacelle 216 and engine core 212 . FIG. 3 shows a view from aft of an engine 210 according to one embodiment in which similar parts have similar reference numerals to those shown in FIG. 2 . Thus there is shown a nacelle 216 , an engine core 212 having radially extending fan outlet guide vanes 249 in the bypass duct 216 located towards the front of the engine 210 , but to the rear of the fan rotor (not shown), the mixer fairing 228 , the tail-cone cone 240 and turbine outlet guide vanes 256 .
[0056] The mixer fairing 228 is substantially axi-symmetric with the exception of a portion which meets a splitter in the form of a pylon 253 which is suspended from the underside of a wing of the aircraft and carries the weight of the engine. The mixer fairing 228 is mounted to the pylon 253 via mounting rails 255 through which, or parallel to which, an actuating force can be provided to translate the mixer fairing 228 .
[0057] The telescopic tail-cone 240 can be translated from a first position to a second position, thereby adjusting the mixer nozzle output flow area. The tail-cone 240 includes a first portion which is generally cylindrical and which is snugly received within a corresponding passageway in the rear of the engine core. The first portion is attached to a second, diverging portion which in turn connects to a third portion which converges on the centreline of the engine and is the portion which defines the mixer duct nozzle 224 .
[0058] The axially translating tail-cone 240 can be an axi-symmetric design which is mounted on an internal structure cantilevered from the turbine aft bearing support structure or frame.
[0059] The axially translating mixer fairing 228 and the translating tail-cone 240 may be deployed by various actuator types as known in the art such as those used for deploying aero engine thrust reverser doors and cascades. These actuator types include, but are not limited to, hydraulic or pneumatic rams or motors or electric motors acting through screw-jacks. As will be appreciated, the actuation system will be designed either to fail fixed, or to fail safe by slowly retracting so that cold nozzle areas are maximised and the risk that the fan will surge is minimised.
[0060] The relationship between the nacelle 216 , mixer fairing 228 , engine core fairing 226 and tail-cone 240 defines four minimum flow areas. The first is the bypass nozzle flow area 248 which is defined between the radially outer wall 237 of the mixer fairing 228 and an inner wall of the nacelle 216 . The second is the mixer cold throat area 250 which is defined between the trailing edge of the core fairing 226 and the radially inner wall 234 of the mixer fairing 228 . The third is the core nozzle flow area 252 which is defined between the trailing edge 227 of the core fairing 226 and the hub extension 244 of the turbine outlet guide vane assembly 256 at the aft end of the core 212 . The fourth is mixer duct nozzle flow area 254 which is defined between the trailing edge 232 of the mixer fairing 228 and a convergent portion 242 of the tail-cone 240 .
[0061] In use, either or both of the tail-cone 240 and mixer fairing 228 can be moved to a plurality of different positions so as to vary the minimum flow areas of the bypass nozzle 220 , mixer cold throat area 250 , and mixer duct nozzle flow area 254 . The core nozzle flow area 252 is fixed in the described embodiment, but it will be appreciated that there may be examples in which this is not the case. These two degrees of freedom enable the overall nozzle area and the mixer area ratio to be optimised independently for each flight condition. In this way the ratio of hot mixed jet and cold jet velocities can also be optimised at all conditions to maximise propulsive or Froud efficiency, or to minimise noise, or one or both at different flight conditions.
[0062] FIGS. 4 , 5 and 6 show schematic plots of the trailing edge of a nacelle 216 , a mixer duct fairing 228 in first and second positions, a trailing edge of the core nozzle, and a tail cone 240 in first and second positions. The bypass nozzle flow area 248 , mixer cold throat area 250 , and the mixer duct nozzle flow area 254 are indicated by the solid and dashed lines for the first and second positions, the latter being further denoted with primed numbers. It will be noted here that the mixer duct 222 includes a chute between the tail cone 240 and mixer fairing 228 which has a convergent portion and a seemingly divergent portion. However, the reduction in mean diameter may or may not compensate for an increase in chute depth, so the minimum passage cross-section or throat plane 254 may be located at, or alternatively slightly upstream of, the exit of the mixer duct nozzle 224 .
[0063] In FIG. 4 , the first and second positions of the mixer fairing are displaced horizontally by approximately 5% and the first and second positions of the tail cone are displaced horizontally by approximately 10% of the outer diameter of the cold nozzle. This provides an increase of 7.5% to the total geometric flow area of the bypass duct and mixer duct nozzles when the mixer fairing 228 and tail cone 240 are retracted from the second position to the first position. This area increase can be utilised for operation at low power and low Mach numbers.
[0064] In FIG. 5 , the mixer fairing 228 is retained in a fixed position, and the tail cone 240 alone is horizontally displaced by 5%. This changes the mixer duct nozzle area, but has no effect on the bypass duct nozzle area 248 or the mixer cold throat area 250 . It changes the total geometric area of the bypass duct and mixer duct nozzles by about 5%, potentially increasing fan flow by a similar amount. This is a mechanically simpler arrangement, but it has less scope to vary the fan flow and may suffer increased aerodynamic losses from larger variations in Mach number in the mixer cold throat area 250 .
[0065] FIG. 6 relates to another embodiment in which the mixer fairing 228 is mounted to the tail cone 240 , by means of an assembly of struts or vanes 258 so as so to remove the need for the pylon support described in relation to FIG. 3 . In this embodiment, there is no separate actuation for the mixer fairing 228 and it is always translated together with the tail cone 240 . Here, the first and second positions for the mixer fairing 228 and tail cone 240 are displaced by 8% which results in a change of 3% in the total bypass duct and mixer nozzle areas.
[0066] As will be appreciated, the profiles or slopes of the mixer fairing 228 and tail cone 240 affect the rates of change of the nozzle areas with relative axial displacement. FIG. 7 shows an alternative embodiment, having a short nacelle 216 (one where the bypass duct nozzle is forwards of the last turbine stage) in which a portion of the radially outer wall of the mixer fairing 228 downstream of the leading edge 230 is substantially parallel to the axis of translation. Hence, horizontally translating the mixer fairing 228 from a first position to a second position produces no change in the bypass nozzle flow area 248 , but, assuming that the tail cone is fixed, the mixer cold throat flow area 250 and mixer duct nozzle flow area 254 will change (as indicated by the primed numbers).
[0067] It will be appreciated any of the mixer fairings may have a portion of radially outer wall downstream of the leading edge 230 which is substantially parallel to the axis of translation and so translating the mixer fairing between a first and second position alters the output flow area of the mixer nozzle and moving the mixer fairing between a second and third position alters the output flow area of the bypass nozzle.
[0068] As noted with the embodiments in FIGS. 4 to 6 , it is possible to have convergent-divergent nozzles, where the minimum passage cross-section or throat plane is slightly upstream of the final nozzle. Using the translating mixer fairing 228 and tail cone 240 , it is also possible to make a convergent-divergent nozzle with a variable area ratio or to transition between convergent and convergent-divergent designs by translating either the mixer duct fairing 228 or the tail cone 240 or both. A convergent-divergent nozzle may give performance benefits for high cruise speed aircraft with moderately high fan pressure ratios, and it can further increase the fan nozzle effective flow area at low speeds.
[0069] Further, by appropriate annulus profiling and differential axial translations of the mixer fairing 228 and tail cone 240 it is possible to vary the area ratios of the nozzles whilst keeping the overall nozzle area constant. In this way the static pressure in the mixing plane and hence the turbine expansion ratio can be varied. This will also affect the mixed jet velocity at the exit plane, enabling the jet velocity ratios to be optimised for noise and efficiency at multiple engine conditions.
[0070] Further features may be incorporated in the mixer duct 222 and the mixer fairing 228 . For example, the mixer duct 222 may incorporate cooling apparatus such as a heat exchanger which utilises at least a portion of the mixer fairing surface and bypass airflow to provide cooling. This could be utilised as a first stage of cooling the engine oil for example. In one embodiment, the surface cooler has a smooth outboard surface to minimise drag, but may incorporate surface features such as cooling fins on the inboard surface to aid cooling. The surface cooler may be formed as an integral structural element of the mixer fairing so as to aid thermal conduction and increase the cooling efficiency. Heating the smooth outer surface of the cowl will have the additional benefit of reducing the cowl drag component of the overall afterbody drag.
[0071] As will be appreciated, where the mixer fairing 228 translates forwards and aft, it will be necessary to provide flexible or telescopic connections for the fluid lines connecting the surface cooler.
[0072] In yet another embodiment, the outboard surface of the mixer fairing 228 could be fitted with an inflatable elastomeric bladder to enable a further reduction of the bypass nozzle area. Further, the mixer duct nozzle area could also be reduced by means of a bladder or other moving surface on the inboard side of the mixer fairing 228 . In other embodiments, the invention could be combined with other known means of varying the external diameter and exit flow area or shape of the bypass nozzle in order to provide a larger area variation or to provide noise suppression or both as described for example in GB2374121.
[0073] In use, the axial displacements of the mixer fairing 228 and tail cone 240 are controlled by the engine control system to provide optimal nozzle flow areas according to the engine's operating condition and flight environment. The fan exit nozzle areas may be set to be the minimum required to give safe margins against fan surge and fan flutter as appropriate to the operating condition. For example the fan exit nozzle areas could be maximised at takeoff where the low air speed and cross-winds have the greatest potential to compromise fan surge margin. At other operating conditions the fan exit nozzle areas may be optimised to minimise fuel burn or engine operating temperatures or shaft speeds or noise. For example, the final nozzle areas may be minimised at top of climb, maximised at take-off and low power conditions and have intermediate flow areas at cruise. Generally, the output flow area of the bypass nozzle and the output flow area of the mixer nozzle may be reduced with an increase in fan speed.
[0074] FIG. 8 shows a thrust reverser in the form of cascade thrust reverser assembly 236 which is incorporated into the nacelle 216 of the engine 210 . In reverse thrust operation the cascades 261 are exposed by translation of the aft part 262 of the nacelle 216 to a further aft position 262 ′ and by movement of blocker doors 263 from their normal stowed positions to their deployed positions 263 ′. The deployment of the blocker doors 263 substantially blocks-off the aft end of the bypass duct 218 , diverting the majority of the bypass air flow through the cascades 261 to provide reverse thrust.
[0075] FIG. 8 shows the deployed blocker doors 263 ′ close to the core fairings 226 which restricts flow through the mixer duct 222 to the mixer nozzle 224 . When bypass airflow into the mixer duct 222 is reduced in reverse thrust operation, the static pressure at the core nozzle 214 is reduced, increasing the expansion ratio across the turbines and the work transferred to the fan. At the same time the reduction in airflow through the mixer duct nozzle 224 reduces its exhaust velocity and reduces the residual forward thrust from the core engine, increasing the net reverse thrust. This benefit relative to conventional separate jet engines can be enhanced by maximising the mixer duct nozzle area 254 by either or both of translating the mixer fairing 228 to its aftmost position 228 ′ and retracting the convergent portion 242 of the tail cone 240 to its furthest forward position 242 ′.
[0076] In alternative embodiments the deployed blocker doors 263 ′ might form a restriction with, or seal against, the outer surface 237 , or the leading edge 230 , of the mixer fairing 228 and allow some bypass air to flow through the mixer duct 222 . This can be beneficial if the mixer fairing incorporates a heat exchanger and needs to be protected from the hotter core exhaust gasses emerging from the turbine outlet guide vanes 256 .
[0077] The blocker door 263 includes a plurality of apertures 264 in an upstream flow path relative to the leading edge of the mixer fairing 228 . The apertures 264 allow a flow of cooling air to pass-over the leading edge and around the mixer fairing 228 to provide cooling during reverse thrust operation. Such cooling may be necessary in lieu of the blocked bypass air which would ordinarily cool the mixer duct, and to help reduce the ingestion and heating effect of the core exhaust which may otherwise be drawn upstream in the mixer duct and around and outboard of the mixer fairing 228 . The cooling may be in the form of discrete jets impinging on the leading edge 230 of the mixer fairing 228 or a diffused flow depending on the configuration and position of the holes 264 relative to the mixer fairing 228 .
[0078] It will be appreciated that alternative thrust reverser designs may be substituted for the fixed cascade reverser, including, but not limited to, translating cascade reversers and pivot door reversers.
[0079] FIG. 9 shows a schematic diagram of parts of possible thrust measurement and control systems for the translating mixer fairing and for the tail cone if this is also independently moveable.
[0080] The thrust measurement system includes a processor 910 which may be part of a larger engine control system 920 . The thrust measurement processor 910 is arranged to receive signals from sensors 912 , 914 which detect and provide signals indicative of either or both of the positions of the mixer fairing 228 and tail cone 240 , and a sensor 928 which indicates the state of the thrust reverser, and signals from other sensors 916 that for example measure engine pressures, temperatures and shaft speeds to enable the thrust to be accurately determined. The thrust measurement processor 910 may also take aircraft operating conditions as inputs. The thrust measurement processor 910 may be configured to determine the thrust being provided by the engine at any given time.
[0081] It will be appreciated that the sensors 912 , 914 may also be used to provide a signal to a separate actuator control sub-system 922 which may control the actuators 924 which position the mixer fairing 228 and tail cone 242 , and confirms correct operation and deployment of these components.
[0082] The control of the actuators may be achieved by algorithms taking indications of engine and/or aircraft operating conditions as inputs provided by the engine control system 920 and flight management system 926 . Alternatively the control of fan surge or flutter margin may be achieved using feedback from sensor systems 918 designed to sense the onset of surge or levels of fan vibration. The vibration may be indicative of a systems failure or incipient systems failure, or detection of actual or potential damage to the fan from a bird-strike or other foreign object impact. When increased vibration or fan surge is detected, the output flow area of the bypass nozzle and the output flow area of the mixer nozzle can be increased. An over-riding command to maximise nozzle areas could also be provided by the pilots or by a flight management system 926 in order to respond to abnormal conditions, such as operation following a bird-strike, engine surge or other event.
[0083] In an aircraft that features multiple engines with shaft speed synchronisation and/or synchrophasing to control especially the noise produced by multiple fans, the engine control system 920 may also command the actuator control sub-system 922 to harmonize the control of nozzle areas between different engines. Typically this would be achieved by designating one engine as the master and with limited authority commanding the other engine or engines to match its operating parameters. These parameters may include positioning of the mixer fairing 228 and tail cone 240 .
[0084] The above described embodiments are examples of the invention defined by the claims and should not be taken to be limiting. For example, although the mixer fairing 228 is shown as having a continuous circumferential radius at each axial point (with the exception of where it joins the pylon 253 ) the annulus may include lobes or undulations to aid mixing of the various airstreams. The trailing edge 232 of the mixer fairing 228 may also be serrated to aid mixing and reduce noise. FIG. 8 shows a lobed or forced mixer 257 that may be attached to the trailing edge 227 of the core fairing 226 to enhance mixing of the hot and cold airstreams.
[0085] Where possible, features described as part of a particular embodiment should not be taken to be limited as being used with that embodiment only, with the possibility of incorporation with other embodiments contemplated where possible. | A gas turbine engine comprising: a bypass duct having a bypass nozzle; an engine core having a core nozzle; and, a mixer duct defined by a mixer fairing and having a mixer nozzle, wherein the mixer duct is arranged to receive an airflow from the bypass duct through a mixer duct inlet and an airflow from the engine core, when in use, and the geometry of the mixer duct is selectively adjustable by moving the mixer fairing relative to the bypass duct and engine core in use. | 8 |
BACKGROUND OF THE INVENTION
Numerous vehicles of the track or wheel type to perform various material handling operations have been proposed. One type of vehicle that has received a considerable degree of attention is a small unit that incorporates four wheels which are driven by two separate power sources and the steering or turning movement is accomplished by driving the pair of wheels on one side of the vehicle in one direction while the second pair of wheels is either in a neutral condition or driven in the opposite direction. These vehicles have generally been referred to as skid steer vehicles.
One type of skid steer vehicle that is presently commercially available incorporates hydraulically actuated fluid translating devices as the power train between the engine and the respective pair of wheels. In order to simplify the construction and reduce the cost of vehicles of this type, the actuation of the fluid translating devices is controlled through manual control levers that respectively cooperate with the two translating devices on opposite sides of the vehicle and the fluid translating devices are maintained in engagement by manual forces applied to the control levers. The control levers may additionally function to control the movement of the lift arms and the material handling attachment. For safety reasons, the control systems are designed to automatically return to a neutral position upon release of the control levers.
SUMMARY OF THE INVENTION
The present invention is directed to a unique locking arrangement to retain the control levers in their neutral position when the vehicle is not intended to be operative. In particular, the locking arrangement is activated and inactivated in response to the presence of an operator in the operator's seat of the vehicle. The control levers are locked in their neutral position until such time as an operator occupies the vehicle seat. This prevents the operation of the vehicle without an operator in the vehicle seat.
According to the present invention, the locking arrangement includes a locking member movable between a first position in locking engagement with the control lever when it is in its neutral position and a second position in disengagement with the control lever. The locking member is biased towards its first position and is automatically moved to its second position when an operator is seated in the vehicle seat.
More specifically, the locking member is pivotally mounted to the vehicle body about a substantially horizontal axis. The locking member includes a locking flange having an opening therethrough for locking engagement with an end portion of the control lever. The vehicle seat is also pivotally mounted to the vehicle body about a substantially horizontal axis. The seat has an up position when it is not occupied and a down position when it is occupied. The locking member has a control flange in contact with the underside of the seat such that movement of the seat between its up and down positions is translated to pivotal movement of the locking member between its locked and unlocked positions. A spring means is provided to bias the locking member towards its locked position and the seat towards its up position. The operator's weight when seated in the seat is effective to move the seat to its down position and the locking member to its unlocked position. The control lever has a stub portion at its end which is in the shape of a truncated pyramid which is received in a rectangular opening in the locking flange when the locking member is in its locked position and the control lever is in its neutral position.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view of a vehicle of the type which incorporates the locking arrangement of the present invention therein;
FIG. 2 is a plan view showing the locking arrangment in combination with a portion of the operating linkages which are controlled by the control lever;
FIG. 3 is an elevational view, partially in section, showing the locking arrangement and operating linkages as in FIG. 2 in relation to the vehicle seat with the control lever in its locked position;
FIG. 4 is an enlarged exploded perspective view of the various parts of the locking arrangement;
FIG. 5 is an end view of the locking arrangement and operating linkages as shown in FIG. 2; and
FIG. 6 is an enlarged view of a portion of the locking arrangent as shown in FIG. 3 with the control lever in its unlocked position.
DETAILED DESCRIPTION
While this invention is susceptible of embodiment of many different forms, there is shown in the drawings and will herein be described in detail one specific embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention to the embodiment illustrated.
FIG. 1 of the drawings shows a tractor vehicle, generally designated by the reference numeral 10. Tractor vehicle 10 consists of a frame structure including body 12 defining engine space 14 at the rear end thereof and forward space 16 for the operator's legs at the forward end thereof. Seat 18 is located intermediate the engine space and the forward space and extends above body 12. Engine 20 is located in engine space 14 at the rear end of body 12, while body 12 is supported on first and second pairs of ground engaging members or wheels 22 rotatably supported on body 12 by stub shafts. One pair of wheels is located on each side of body 12.
Tractor vehicle 10 further includes first and second stanchions 24 extending above body 12 adjacent the rear end thereof on opposite sides of engine space 14. A lift arm 26 is pivotally mounted by pivot pin 28 adjacent the upper end of each stanchion 24. Pin 28 is supported on forwardly extending brackets 29 (only one being shown).
Lift arms 26 extend forwardly along opposite sides of spaces 14 and 16 as well as seat 18 and have front portions 27 directed downwardly adjacent the front end of body 12. Material handling member 30, illustrated as a bucket, is pivotally connected to the front portions 27. Material handling member 30 may take a variety of forms such as a dozer blade, scoop, fork lift, etc.
Hydraulic fluid rams 32 are positioned between each stanchion 24 and its associated lift arm 26 so that the lift arms 26 may be raised and lowered on the vehicle body 12. Also, hydraulic fluid rams 34 are located between the material handling member 30 and the front portions 27 of the lift arms 26 to pivot the material handling member 30 relative to the lift arms 26.
Each pair of wheels 22 on the respective sides of the vehicle is driven through separate power trains which are of identical construction. Each power train is controlled by a separate control lever 36. Each control lever 36, in addition to controlling the power train associated therewith, may perform a second function of either controlling the movement of lift arms 26 through rams 32 or the movement of member 30 through rams 34. The detailed disclosure of the specific linkages associated with the operation of the control levers is not deemed to be necessary for a full understanding of the invention, and, in fact, would tend to obscure the disclosure of the invention. Accordingly, only portions of such linkages are shown in the drawing and described in the disclosure which hereinbelow follows. Suffice it to say, each control lever 36 is pivotal about a transverse horizontal axis to control the power train which drives the wheels and about a longitudinal horizontal axis to control either the movement of the lift arms or the material handling member. Such control lever and linkage assemblies are well known in the art.
The control lever locking arrangement of the present invention will now be described in detail in association with the left side control lever, it being understood that the locking arrangement associated with the right side control lever is identical. Referring to FIGS. 2-6, and in particular to FIG. 3, control lever 36 has an upwardly and forwardly extending section 38, the upper end (not shown) of which is controlled by the operator, and a substantially horizontal rearwardly extending section 40 which is received through member 42. As best seen in FIG. 4, member 42 has a longitudinally extending boss portion 44, a transversely extending boss portion 46 and a longitudinally extending flange portion 48. Member 42 is secured to the frame of the vehicle thorugh a stub shft 50, rigidly secured to the vehicle frame, which extends through boss portion 46 and is secured in place by ring retainers 52, as best seen in FIG. 5. Member 42 pivots about the transverse horizontal axis of shaft 50. Section 40 of control lever 36 extends through boss portion 44 and is secured in place by a ring retainer 54 at one end and an angle bracket 56 secured to control lever 36 at the other end, as best seen in FIG. 3. Control lever 36 is rotational about the longitudinal horizontal axis passing through boss portion 44. It can therefore be seen that control lever 36 is pivotable in a forward and backward direction and rotational in a side to side direction. The forward and backward movement of control lever 46, in cooperation with appropriate linkages, controls the power train which drives a pair of wheels 22. The side to side rotational movement of control lever 36, in cooperation with appropriate linkages, controls either the movement of lift arms 26 or member 30.
Referring to FIGS. 2 and 3, a portion of the linkage which controls the power train associated with one of the pair of wheels 22 is shown for purpose of describing the means to bias the control lever 36 into its neutral position. A link member 58 is pivotally secured at one end to flange 48 through a clevis and pin arrangement and extends through a spring retainer member 60 and is secured to a link and clevis member 62, which in turn is attached to a flange 64 welded to a transverse shaft 66. Positioned within member 60 are a pair of spring retainer cups 70 and 72. Cup 70 is suitably secured to a forward portion of link member 58 and is movable therewith towards cup 72 and cup 72 is suitably secured to a rearward portion of member 58 and is movable therewith towards cup 70. A spring member 74 extends between cups 70 and 72. Link member 58 passes through cups 70 and 72 and spring 74. Spring member 74 is effective to bias control rod 58 and in turn member 40 such that the control lever 36 automatically returns to its neutral position upon release of the control lever by the operator.
As seen in FIG. 3, seat 18 is formed about a sheet metal pan 80 and includes a foam cushion insert 82. The bottom section of pan 80 is secured to a sheet metal plate 84 which has an upturned end 86. A seat support frame 88 is rigidly secured to the vehicle body and includes a substantially horizontal bottom portion 90 and an upwardly and rearwardly extending back portion 92. Plate 84 is pivotally secured to frame 88 about a short pivot pin 94 extending inwardly from each side of the vehicle. Each pivot pin 94 receives three sleeves 96 (only one of which is shown), the two outer sleeves being welded to frame 88 and the middle sleeve being welded to upturned end 86 of plate 84. Accordingly, seat 18 is pivotable about the transverse horizontal axis passing through pins 94.
Referring to FIGS. 3 and 6, a locking member 100 is pivotally secured about a stub shaft 102 which extends inwardly from the vehicle side frame. Locking member 100 includes a cylindrical boss portion 104, through which shaft 102 passes, a locking flange 106 and a control flange 108, which are welded to and extend substantially radially outwardly from boss portion 104. Boss portion 104 is positioned in place about shaft 102 by retaining rings 110, as seen in FIG. 5. Locking flange 106 is formed from a rectangular plate having a centrally disposed rectangular opening 112 passing therethrough. A pair of circular openings 114 are provided through flange 106 adjacent its lower corners. Control flange 108 is formed from a rectangular plate which is curved downwardly at its outer end. Flanges 106 and 108 extend outwardly from boss 104 so as to define an included angle of approximately one hundred and fifty degrees. Locking member 100 is positioned in spaced relationship to seat 18 and the end of control lever 36 such that when flange 106 is in a vertical position, in opposing relationship to the end of control lever 36, the control flange 108 passes through an opening 116 in bottom portion 90 of frame 88 and the curved outer end thereof contacts the underside of plate 84 so as to pivot the front end of seat 18 to an up position. The significance of this space relationship will become more apparent in the description of the operation of the invention. A spring member 118 is provided to bias locking member 100 into a locked position in which locking member 106 is in a vertical position, as shown in FIG. 3. Spring member 118 at one end passes through an opening 114 in locking member 106 and at its other end is received around a stud member 120 secured to the vehicle side frame.
The inner end of control lever 36 has a stub portion 122 formed integrally therewith. Stub portion 122 is preferably shaped in the form of a truncated pyramid to facilitate its receipt through opening 112.
A brief description of the operation of the locking arrangement which hereinbelow follows will further define the space relationships of the various elements. Referring to FIG. 3, locking member 100 is biased into its locked or first position by spring 118. The control lever 36 is biased into its neutral position by spring 74. With the member 100 in its first position and the control lever in its neutral position, stub portion 122 is received through opening 112. The positioning of stub portion 122 through opening 112 prevents the movement of control lever 36 about the longitudinal horizontal axis passing through boss portion 44 and the transverse horizontal axis passing through boss portion 46. Accordingly, control lever 36 is inoperative to activate the linkages which control the movement of corresponding wheels 22 or the lift arms 26 or the bucket 30 associated with that control lever. It should be noted that the curved end portion of control flange 108 is in contact with plate 84 through opening 116 and supports seat 18 in its up position.
At such time as the vehicle 10 is to be put into service, the weight of the operator positioned in seat 18 is effective to pivot seat 18 about the horizontal axis passing through pins 94 into its down position, as shown in FIG. 6. The movement of seat 18 from its up position to its down position is effective to pivot locking member 100 in a counterclockwise direction about shaft 102, into its unlocked or second position, as indicated by the arrow in FIG. 3, against the bias of spring 118. As best seen in FIG. 6, when seat 18 is in its down position and locking member 100 is in its second position, the locking flange 106 is moved rearwardly such that stub portion 122 is no longer positioned within opening 112. As long as the operator remains in seat 18 the locking member 100 continues to assume its second position out of locking engagement with stub portion 122. The control lever 36 is now free to be rotated about the horizontal axis passing through boss portions 44 and 46 to activate the associated linkages to control the movement of vehicle 10 and either the lift arms 26 or the bucket 30 associated with that control lever.
At such time as the operator releases the control lever 36, spring 74 returns control lever 36 to its neutral position and when the operator evacuates the seat 18, spring 118 returns locking member 100 to its first position, which is effective to raise the front end of seat 18 to its up position and stub portion 122 is received through opening 112. Accordingly, the control lever is locked in its neutral or inoperative position.
As can be seen from the above description, the locking arrangment of the present invention provides a simple and inexpensive mechanical means to automatically lock the control lever of a vehicle in a neutral position whenever the vehicle seat is not occupied by an operator. The present invention additionally serves to require that the operator remain seated in the seat while operating the vehicle. | A locking arrangement to arrange a control lever of a vehicle in a neutral position. The locking arrangement is activated and inactivated in response to the presence of an operator in the seat of the vehicle. The locking arrangement retains the control lever in a neutral position when the operator is not in the seat. | 1 |
DESCRIPTION
Technical Field
Oxygen has been separated from gas mixtures containing oxygen by contacting such mixtures with organometallic complexes commonly termed "oxygen carriers". During the contact oxygen is bound to the carrier complexes. After all or a substantial part of the capacity of the carrier to bind oxygen to it has been exhausted the carrier complex is removed from further contact with the feed gas and the bound oxygen is separated from the carrier. In the past this separation has been made either by raising the temperature of the carrier containing bound oxygen causing release of the oxygen from the carrier or by introducing the carrier containing bound oxygen into a zone in which the pressure above the carrier is substantially below atmospheric pressure and this pressure reduction causes release of the bound oxygen. After release of the bound oxygen from the carrier, the carrier may be returned to further contact with the feed gas to repeat the binding of oxygen to the carrier.
The metal complex carriers are commonly dissolved in a solvent and the feed gas is contacted with a solution containing the carrier. The gases other than oxygen contained in the feed gas commonly dissolve to an appreciable extent in the solvent and when either reduction of pressure or elevation of temperature is employed to release the bound oxygen the dissolved nonoxygen components of the feed gas are also released, reducing the purity of the oxygen recovered.
Pursuant to the present invention, the oxygen carriers heretofore used and others are employed to bind oxygen to the carrier, but the release of bound oxygen from the carrier and reactivation of the carrier for further use in binding oxygen is accomplished electrochemically. There is no pressure reduction and no temperature rise and the dissolved gas in the solution of the metal complex carrier is not much released along with the oxygen released by the electrochemical reaction.
BRIEF DESCRIPTION OF THE INVENTION
Pursuant to the present invention, a solution is prepared which contains a polyvalent metal complex oxygen carrier, an electrolyte and a solvent. The three components of the solution must be chemically compatible with each other in the sense that they do not interact with each other. The solvent must be capable of dissolving sufficient of the oxygen carrier to give a molar concentration of at least 0.01 and preferably a higher concentration up to about 5 molar. The solvent must also be capable of dissolving a substantial quantity of the electrolyte selected and if desired may be capable of dissolving a moderate amount of water which permits the use of electrolytes, other than organic electrolytes, which may not be sufficiently soluble in the solvent itself to be useful. In preparing the solution the metal of the oxygen carrier is at a lower valence. An oxygen containing feed gas is then passed through the solution until a substantial proportion of the capacity of the carrier to bind oxygen is exhausted. The product of this contact with the feed gas is then subjected to electrochemical oxidation which raises the valence of the metal of the oxygen carrier to a higher level and this oxidation concurrently releases oxygen. The released oxygen is removed and the oxidized carrier is then electrochemically reduced to bring the metal component of the carrier back to its lower valence and so to restore its capability to bind oxygen. The sequence of contact of the solution with the feed gas, electrochemical oxidation to release bound oxygen and then electrochemical reduction of the oxygen carrier to bring the metal to its lower valence level is repeated over and over as the process is carried on.
DETAILED DESCRIPTION OF THE INVENTION
As indicated above, the solution employed in the process of the invention for removing oxygen from gaseous mixtures of oxygen and other gases consists of three components, a polyvalent metal complex oxygen carrier, an electrolyte and a solvent.
Polyvalent metal complex oxygen carriers are well-known in the art and have been extensively described in the literature.
Niederhoffer, Timmons and Martell in Chemical Reviews 1984, Vol. 84, No. 2, beginning at Page 137, set forth an extensive review of the literature relating to metal complexes which reversibly bind dioxygen (O 2 ), chemically identify a great many complexes and provide equilibrium constants for the reactions of polyvalent metal complexes with oxygen in organic solvent. The numerous polyvalent metal complexes set out in Tables XXXIIID, XXXIIIE and XXXIIIF, which appear on pages 179 through 185 of the publication are suitable for use as oxygen carriers in the process of the invention.
Kimura et al in Journal of the American Chemical Society, 1984, Vol. 106, pp 5497-5505, describe a number of nickel complexes which are oxygen carriers and are suitable for use as such in the present invention.
Schiff base complexes of the following two formulas and their analogs have been found effective oxygen carriers for use in the process of the invention. ##STR1##
Analogs of these two compounds include those in which the polyvalent metal is a transition metal, preferably iron, nickel, manganese, rhodium, copper and ruthenium instead of cobalt, and in which the oxygen atoms are replaced by another elementor group such as sulfur or NH 2 .
The electrolyte component of the solution may be any electrolyte which is soluble in the solvent employed and which is chemically compatible with the solvent and with the oxygen carrier complex. Quarternary ammonium salts, such as tetrabutyl ammonium fluoborate, tetrabutyl ammonium chloride and other tetraalkyl ammonium salts of inorganic acids are suitable electrolytes. Quarternary phosphonium salts are also suitable electrolytes. When the solvent employed has the capacity to dissolve a reasonable amount of water then electrolytes such as sodium chloride and the like which may not be soluble in the solvent without the water being present may be employed with the result that the range of electrolytes which it is feasible to employ is greatly extended.
The solvents employed are organic solvents, preferably polar organic solvents, such as dimethylformamide, N-methylpyrrolidone, dimethylsulphoxide and generally lactones, lactams, amides, amines and the like. The essential property requirements of the solvent are that it be capable of dissolving the metal complex oxygen carriers in amount to provide concentrations at least 0.01 molar and up to much higher concentrations, such as 5 molar, and that it also be capable of dissolving the electrolyte employed in amount sufficient to provide a high level of electrical conductivity to the total solution, and that further that it be chemically compatible with both the oxygen carrier and with the electrolyte employed.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following further description of the invention, reference will be made to the appended drawings, of which:
FIG. 1 is a side view of a cell and experimental set-up for making cyclic voltammetric scans.
FIGS. 2, 3 and 4 are graphic representations of cyclic voltammetric scans.
FIG. 5 is a side view of apparatus in which the invention may be practiced.
DETAILED DESCRIPTION OF THE DRAWINGS
The release of oxygen by electrochemical oxidation of a carrier onto which oxygen has been bound and the reactivation of the carrier species by electrochemical reduction has been demonstrated in a small laboratory apparatus. Experiments in this apparatus have served to demonstrate the electrochemical principles of the invention.
Experiments were conducted in a 30 ml glass container (cell). Platinum wire (0.5 mm diameter) spiral electrodes were used as the test and the counter electrodes. The electrode area exposed to the solution was 0.63 cm 2 . The reference electrode was a saturated calomel reference electrode. The potential of this electrode with respect to the standard hydrogen electrode is +0.242 V. The electrodes were fitted to the cell in such a manner that the test electrode and the reference electrodes were in close proximity to minimize IR drop.
All experiments were conducted in the cell with 10 ml of N-Methyl-pyrrolidone (NMP) and 0.2 g of tetrabutyl ammonium tetrafluoborate (BU 4 NBF 4 ). The NMP served as the solvent, and the Bu 4 NBF 4 served as the electrolyte. The electrodes were totally immersed in the solution. The cell was designed such that air or argon could be sparged through the solution when desired. The container temperature was maintained at 5° C. The solution was stirred when desired with a magnetic stirrer.
To investigate the electrochemical behavior of the system, the current passing through the solution was monitored as the voltage of the test electrode was varied. This technique, known as cyclic voltammetry (CV), is a standard technique for observing electrochemical reactions, described in "Electrochemical Methods", Bard & Faulkner, John Wiley & Sons, New York 1980. The technique relies on the principle that in any given electrolyte system, a given electrochemical reaction will occur at a specific potential. For example, tables of Standard Reduction Potentials (e.g. in the Handbook of Chemistry and Physics, 52nd edition, page D-111) indicate the potentials at which hundreds of reactions occur in aqueous solution. Consequently, in cyclic voltammetry, electrochemical reactions appear as waves in the plot of current versus applied potential.
Cyclic voltammetry was used to identify three electrochemical reactions: (1) the oxidation of the carrier, (2) the reduction of the carrier, and (3) the reduction of dissolved molecular oxygen. Observation of the first two electrochemical reactions serves to demonstrate the ability to oxidize and reduce the oxygen carrier complex, and observation of the third reaction serves to identify the presence of dissolved molecular oxygen in solution.
To identify the potential at which dissolved molecular oxygen is reduced and to prove that the solvent and electrolyte do not undergo electrochemical oxidation or reduction, cyclic voltammetry was performed on the solution in the absence of carrier (i.e. only 10 ml NMP and 0.2 g Bu 4 NFB 4 ). In one case argon was bubbled through the solution for 15 minutes prior to the CV scan. In the next case air was bubbled through the solution for 15 minutes prior to the CV scan. There were no electrochemical reactions observed in the argon scan, whereas in the presence of dissolved molecular oxygen, FIG. 2 shows an electrochemical reaction at -0.43 V. This reaction is the electrochemical reduction of oxygen. Therefore, in this electrolyte system, the waves at -0.43 V in the current vs. voltage plot indicates the presence of dissolved molecular oxygen. These results are shown in FIG. 2 of the drawings.
To identify the presence of the electrochemical reduction and oxidation of the carrier itself, argon was bubbled through the solution for 15 minutes and then added 0.3 ml of Complex-I (Salen) dissolved in NMP. A CV scan was run and electrochemical oxidation was observed at 0.18 V, 0.36 V, 0.88 V, and 1.2 V. In FIG. 3 electrochemical reduction is shown at 0.04 V. These experiments serve to show that oxidation and reduction of the carrier can be performed electrochemically and that the potential of this oxidation and reduction is such that there can be no confusion between the electrochemical oxidation or reduction of the carrier and the reduction of dissolved molecular oxygen. Therefore, when air is introduced into the system, the presence or absence of dissolved molecular oxygen can be established unequivocally.
Having established the potentials at which the oxidation and reduction of the carrier occur and having established a method for indicating the presence of dissolved molecular oxygen, air was bubbled through the solution for 15 minutes. CV scans were then performed in which seven different peak voltages at which to reverse the scan were chosen. Referring to FIG. 4, scan curve 1 shows no oxidation of the carrier, it is apparent that there is no detectable dissolved molecular oxygen (i.e. if any is in the solution at all, it is bound to the carrier because there is no reduction wave near -0.43 V). As the peak scan voltage was increased waves indicating the oxidation and reduction of the carrier appear and the appearance of the wave near -0.43 V indicating the presence of dissolved molecular oxygen. Finally, at the highest peak voltage scan curve 7, a substantial oxygen reduction wave has appeared indicating the release of bound oxygen. The results show that without electrochemical oxidation of the carrier, no dissolved molecular oxygen is detectable, but that with electrochemical oxidation, bound oxygen is released to the solution. In a fully optimized commercial process, this dissolved oxygen, when released, would supersaturate the solvent with oxygen causing formation of oxygen bubbles which could be gathered as the product of the process. Further, the carrier #1 which normally degrades to an inactive peroxo dimer in a short time under the conditions employed, is readily reactivated through electrochemical oxidative decomposition of the peroxobridged dimer.
One embodiment of an apparatus assembly which may be used in carrying out the process of the invention is shown in FIG. 5 of the drawings. Vessel 1 is either a cylindrical or rectangular container for the solutions employed in the invention. The vessel is divided into two compartments of approximately equal volume by a central divider 2, the lower portion of the divider is a permeable membrane which may be loosely packed fiber or asbestos or the like which prevents intermixing of the liquids in the left-hand and right-hand compartments of the container but provides liquid electrolytic communication between the two compartments. The upper portion of the divider is a metal sheet. Feed gas is introduced through line 3 into the left-hand compartment of vessel 1. Line 4 is an exhaust line through which the feed gas depleted in oxygen content is removed from the compartment. The upper surface 5 of the solution lies at a level below the top of container 1 and provides a gas space 6 between the upper level of the liquid and the upper face of container 1. Solution is withdrawn from the upper part of the liquid body in the left-hand compartment through line 7 and is passed through that line into the bottom portion of the right-hand compartment of vessel 1. Pump 8 controls the rate of circulation of the liquid material. Liquid is withdrawn from the upper part of the right-hand compartment through line 9 and is passed through that line into the bottom part of the left-hand compartment. Gas enriched in oxygen is pulled through line 12 by fan 13. Metal mesh electrodes 10 are placed in the lower portions of the left-hand and right-hand compartments of the vessel. Cell 11 is connected to the two metal mesh electrodes, the left-hand electrode being the cathode and the right-hand electrode being the anode in the system.
Operation of the apparatus shown in the drawing is as follows. Vessel 1 is filled with a solution, such as any of the solutions shown in the above table. The vessel is not completely filled but a gas space several inches in height is left above the liquid level and the top of the vessel. After the solution is introduced into container 1, air is passed through line 3 into the left-hand compartment of the container until a substantial portion of the capacity of the solution to absorb oxygen has been exhausted. Pump 8 is then activated and the movement of solution between the two compartments is initiated. Passage of the electric current to the electrodes is initiated. Oxygen is taken up by the solution in the left-hand compartment of the vessel and air depleted in oxygen is withdrawn through line 4. The solution-containing carrier bound oxygen is then drawn through line 7 and introduced into the lower part of the right-hand compartment where it comes into contact with the anode. Through contact with the anode the metal component of the oxygen carrier is oxidized to a higher valence and the oxygen which is bound to the carrier is concurrently released. The released oxygen is withdrawn through line 12. Liquid is withdrawn from the upper portion of the right-hand compartment where the liquid contains the oxygen carrier metal at a higher valence and is passed through line 9 into the lower part of the left-hand compartment where it comes into contact with the cathode. At the cathode the metal component of the carrier is reduced to a lower valence and its capacity to bind oxygen is restored and further oxygen is picked up from the air introduced through line 3. Operation is continuous. Air is continuously introduced into the left-hand compartment of the vessel. Air depleted in oxygen is continuously withdrawn through line 4. Solution containing oxygen bound to the carrier is continuously passed through line 7 from the left-hand compartment to the lower part of the right-hand compartment, the oxygen carrier containing bound oxygen is continuously oxidized by contact with the anode and oxygen is continuously withdrawn through line 12 as product. Solution containing the metal carrier with its metal at a higher valence level is continuously withdrawn through line 9 and passed into the lower part of the left-hand compartment where it is contacted with the cathode and reduced to the lower valence level at which its capacity to bind oxygen is restored.
The process may be operated at temperatures in the range -30° C. to +100° C. Temperatures in the range -15° C. to 20° C. being preferable, the process is ordinarily but not necessarily operated at atmospheric pressure.
When very high purity oxygen is desired the oxygen recovered in the first contact of the solution containing bound oxygen with the anode may be accumulated and further purified by employing it as the feed gas. | A process for separating oxygen from gas mixture containing oxygen is disclosed. The gas mixtures are contacted with a solution of an organometallic complex oxygen carrier and an electrolyte in an organic solvent. During the contact, oxygen is bound to the carrier. After the contacting step is completed the solution is electrochemically oxidized with resultant release of oxygen which is recovered. The solution is then electrochemically reduced bringing the oxygen carrier to its original condition and ready for reuse. | 2 |
BACKGROUND
Drilling offshore oil and gas wells includes the use of offshore platforms for the exploitation of undersea petroleum and natural gas deposits. In deep water applications, floating platforms (such as spars, tension leg platforms, extended draft platforms, dynamically positioned platforms, and semi-submersible platforms) are typically used. One type of offshore platform, a tension leg platform (“TLP”), is a vertically moored floating structure used for offshore oil and gas production. The TLP is permanently moored by groups of tethers, called tension legs, that eliminate virtually all vertical motion of the TLP. Another type of platform is a spar, which typically consists of a large-diameter, single vertical cylinder extending into the water and supporting a deck. Spars are moored to the seabed like TLPs, but whereas a TLP has vertical tension tethers, a spar has more conventional mooring lines.
Offshore platforms typically support risers that extend from one or more wellheads or structures on the seabed to the platform on the sea surface. The risers connect the subsea well with the platform to protect the fluid integrity of the well and to provide a fluid conduit between the platform and the wellbore.
Risers that connect the surface wellhead on the platform to the subsea wellhead can be thousands of feet long and extremely heavy. To prevent the risers from potentially buckling under their own weight or placing too much stress on the subsea wellhead, upward tension is applied, or the riser is lifted, to support a portion of the weight of the riser. Since offshore platforms often move due to wind, waves, and currents, for example, the risers are tensioned such that the platform can move relative to the risers. To that end, the tensioning mechanism often exerts a substantially continuous tension force on the riser.
Risers can be tensioned by using buoyancy devices that independently support the riser, which allows the platform to move up and down relative to the riser. This isolates the riser from the heave motion of the platform and eliminates any increased riser tension caused by the horizontal offset of the platform in response to the marine environment. This type of riser is referred to as a freestanding riser.
Hydro-pneumatic tensioner systems are another type of a riser tensioning mechanism. In this type of system, a plurality of active hydraulic cylinders with pneumatic accumulators is connected between the platform and the riser to provide and maintain the desired riser tension. The platform's displacement, which may be due to environmental conditions, that causes changes in riser length relative to the platform are compensated by the tensioning cylinders adjusting for the movement.
Floating platforms, which are used for deeper drilling and production, often encounter additional challenges, such as thermal expansion, due to the fact that the drilling extends into very high temperature formations where special drilling equipment may be required. At high temperatures, the riser, which extends from the sea floor, is subject to expansion and contraction. And that expansion and contraction of the production/drilling riser may result in undesirable movement, such as buckling, in response to temperature changes.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the various disclosed system and method embodiments can be obtained when the following detailed description is considered in conjunction with the drawings, in which:
FIG. 1 is an illustrative, production riser system for elevated temperatures with completion landed;
FIG. 2 is an embodiment of an annular tensioner with castellated gathering fingers;
FIG. 3 is an illustrative, production riser system with production in operation at elevated temperatures;
FIG. 4 is an illustrative, production riser system with control lines running outside the annular tensioner space;
FIG. 5 is an illustrative offshore drilling system in accordance with various embodiments;
FIG. 6 is an illustrative drilling riser system including an outer riser with a nested internal riser; and
FIG. 7 is the drilling riser system of FIG. 6 with the inner riser installed within the outer riser.
DETAILED DESCRIPTION
The following discussion is directed to various embodiments of the invention. The drawing figures are not necessarily to scale. Certain features of the described embodiments may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
Certain terms are used throughout the following description, and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis.
Disclosed herein is a system for conveying fluid from a subsea well to a floating platform. The system includes a subsea wellhead, and an outer tubing connected at a lower end and supported in tension at the upper portion by the floating platform. Inner tubing is also included. The inner tubing is connected at a lower end to the subsea wellhead and is dynamically supported in tension at an upper end by the outer tubing so that the inner tubing can move relative to the outer tubing.
An embodiment of the system c facilitate production of fluid from a subsea well to a floating platform. The system includes a subsea wellhead, a production riser connected at a lower end to the subsea wellhead and supported in tension at an upper portion by the floating platform. A production tubing, a production tree, and a tubing hanger are also included in this embodiment. The production tubing is connected at a lower end to the subsea wellhead and dynamically supported in tension at an upper end by the production riser so as to be capable of movement relative to the production riser. The production tree is fixed to the upper portion of the production riser. The tubing hanger is landed in and supported by the production tree with the production tubing being in fluid communication with the tubing hanger while being dynamically supported for movement relative to the tubing hanger.
FIG. 1 illustrates an embodiment of such a production riser for elevated production fluid temperatures. The production riser system includes a production riser 120 connected with a subsea wellhead (not shown). A production tubing 108 extends within the production riser 120 and is in fluid communication with the production fluids from the well. A dynamic tensioner 112 maintains the production riser 120 in tension as the floating platform 317 moves. The production riser system also includes a production tree 104 installed on the upper end of the production riser 120 . The production tree 104 control the flow of fluids into and out of the well, and can be a vertical or horizontal “spool” tree. As shown, the production tree 104 is a horizontal tree.
The production tree 104 supports a tubing hanger 102 that is in fluid communication with the production tubing 108 . And that production tubing 108 is dynamically supported for movement relative to the tubing hanger 102 , as explained below. The production tubing 108 further includes a slip connector 124 at a position along the length of the inner tubing. Although the slip connector 124 is shown near the upper portion of the riser system, the connector can be located in the center of the riser or even at the lower subsea portion of the production riser system.
The slip connector 124 includes an overshot tubing 125 that includes an open lower end and internal volume. A polished bore rod (PBR) 110 in fluid communication with the well below the overshot tubing extends into the internal volume of the overshot tubing through the overshot tubing's open lower end and is movable within the overshot tubing. The overshot tubing also includes a centralizer 127 for centering the overshot tubing within the production riser 120 . The overshot tubing also includes a dynamic seal 129 for sealing against the outside of the PBR as explained further below. The centralizer centralizes the overshot tubing within the production riser 120 for easier insertion of the PBR into the overshot tubing without damaging the overshot tubing's dynamic seal against the PBR.
The system for conveying fluids further includes an outer tubing with an internal shoulder, an inner tubing with an external shoulder, and an annular tensioner landed on both the outer tubing internal shoulder and the inner tubing external shoulder. The annular tensioner is movable to dynamically support the production tubing in tension. As shown in the embodiment of a production riser system, the annular tensioner 112 includes a tension plug 114 surrounding the production tubing with an outer diameter larger than the inner diameter of the production riser internal shoulder. The annular tensioner 112 also includes a tension piston 116 surrounding the production tubing with an inner diameter less than the outer diameter of the production tubing external shoulder. The tension plug 114 and tension piston 116 are located in the production riser and seal against the inside of the production riser and the outside of the production tubing to form a sealed chamber. The tension piston 116 is movable within the production riser with respect to the tension plug 114 from pressure in the sealed chamber as the production tubing moves relative to the production riser. Both the tension piston 116 and the tension plug 114 include castellated gathering fingers 235 a and 235 b for coupling to each other, as illustrated in FIG. 2 . The castellated gathering fingers on both the tension plug 114 and the tension piston 116 include an angled ramp area. These angled ramps gather the control lines inside the sealed chamber to avoid pinching as the tensioner plug 114 and the tensioner piston 116 come together.
As shown in FIG. 1 , the tension piston 116 , when initially installed, may rest on the tension plug 114 , and be designed to place the production tubing in tension. One option thus includes landing in tension. However, another option includes applying pressure to the annular tensioner 112 sealed chamber and holding that tubing 108 in tension.
The production riser itself could be several hundred to several thousand feet. The tension piston rests on the tension plug, which rests on tension joint that is supported by the dynamic tensioner on the platform. The top of the tension joint is pulled up, and the bottom of the tension joint is pushed down; and the tension joint body goes into tension, but sums to zero. The external tensioner setting is established to keep the external riser pipe 120 in tension. This is accomplished with sufficient tensioner setting to keep the production riser 120 in tension.
For installation, the production riser is attached to the subsea wellhead and set up in tension using the dynamic tensioner. The production tubing is then run in and attached to the subsea wellhead. When enough of the production tubing is installed, the annular tensioner components are installed and the production tubing is placed in tension. Completion related control lines 126 are run through the tension piston 116 , coil around the production tubing inside the sealed chamber and then exit the tension plug 114 . Penetrations are sealed with fittings, lines are continuous, and the coils allow the necessary movement up and down of the tension piston. The various control lines 126 are used to operate various valves in the permanently installed subsea piping.
Finally, the PBR is attached to the production tubing and the tubing hanger 102 and overshot assembly is lowered into the production tree allowing the overshot to swallow the PBR 110 . The blowout preventer is then removed, all control lines 126 are finalized, and tree 104 is capped.
FIG. 3 illustrates a production riser system operating with production fluid at elevated temperatures. Here, the tubing 308 has expanded in length due to heating. The overshot connector 324 helps to accommodate the expanded tubing 308 while maintaining the dynamic seal with the PBR. The annular tensioner sealed chamber pressure supply is at a level sufficient to move the tension piston upwards with the production tubing outer shoulder and thus hold the production tubing in tension despite the upward movement. Alternatively, a pressure supply may maintain the pressure in the sealed chamber so as to place enough force on the tension piston to keep the production tubing in tension. The necessary pressure in the sealed chamber may be determined based on measurements of a characteristic of the sealed chamber, such as pressure, temperature, or position of the production tubing.
There are multiple advantages to the presented invention. One main advantage is that the floating structure buoyancy needs are reduced, along with the tensioner system capacity. Normally, a subsea, wellhead tubing hanger carries significant tubing loads. Further, this system allows the external riser to stay in tension with standard external tensioner approach. This system may also be used to support a drilling riser with an inner pipe requirement. Overall, it is important to note that this exemplary system supports the inner pipe in tension, avoids compression, and avoids buckling by use of an the annular tensioner. Finally, all seals and annuli may be monitored from the floating structure deck.
As discussed above, there are various options for configuration and the use of multiple components. Another advantage of the present invention is the ability to employ several methods for not requiring the down hole lines to penetrate the annular tensioner space. The control lines would simply exit the tension joint, radially by several methods. FIG. 4 shows a method which could have a taller tension plug 414 with several radial line exits for hydraulic service. This solution does not address the optical line. This option does not require the use of orientation of the tension plug to the tension joint because each subsequent line is ported stacking up the plug. In other words, once the tension plug is in place, the tension plug porting and the tension joint porting would line up without orientation. A control, monitoring, and injection lines manifold 432 would be positioned upon the TLP deck 434 . An advantage of this embodiment would be the elimination of penetration through the annular tensioner space in the riser system, which normally would require numerous control, monitoring, or injection lines.
Another alternative would allow direct connection of the control lines, but also require orientation of the plug with respect to the tension joint. A port can be coupled directly to a control line. By “direct,” it is intended to include a connection or coupling between a control line and a port that does not requires annular seals that are used to seal annular zones. A control, monitoring, and injection lines manifold 432 would be positioned upon the TLP deck 434 . The advantage of this embodiment would be the elimination of penetration through the annular tensioner space in the riser system, which normally would require numerous control, monitoring, or injection lines. This could be a solution on dual barrier drilling riser or on elevated temperature production risers. As an added feature, the system will include control and other down-hole hydraulic and/or fiber-optic lines without sharing space with an annular tensioner feature.
Another embodiment is also included in the present invention. This embodiment is a drilling riser system connected to a wellhead located at a seafloor. The drilling riser system includes an external riser for a floating structure with an external tensioner keeping the external riser pipe in tension. The drilling riser system also includes an internal riser with an overshot slip connector and annular tensioner as described above. The drilling riser system is such that the outer and inner drilling risers allow passage of a drill bit and drill string through the riser to the subsea well.
Referring now to FIG. 5 , a schematic view of an offshore drilling system 500 is shown. The drilling system 500 may be of any suitable configuration. For example, the drilling system 500 may be a dry BOP system and include a floating platform 501 equipped with a drilling module 502 that supports a hoist 503 . Drilling of oil and gas wells is carried out by a string of drill pipes connected together by tool joints 504 so as to form a drill string 505 extending subsea from platform 501 . The hoist 503 suspends a kelly 506 used to lower the drill string 505 . Connected to the lower end of the drill string 505 is a drill bit 507 . The bit 507 is rotated by rotating the drill string 505 and/or a downhole motor (e.g., downhole mud motor). Drilling fluid, also referred to as drilling mud, is pumped by mud recirculation equipment 508 (e.g., mud pumps, shakers, etc.) disposed on the platform 501 . The drilling mud is pumped at a relatively high pressure and volume through the drilling kelly 506 and down the drill string 505 to the drill bit 507 . The drilling mud exits the drill bit 507 through nozzles or jets in face of the drill bit 507 . The mud then returns to the platform 501 at the sea surface 511 via an annulus 512 between the drill string 505 and the borehole 513 , through subsea wellhead 509 at the sea floor 514 , and up an annulus 515 between the drill string 505 and a riser system 516 extending through the sea 517 from the subsea wellhead 509 to the platform 501 . At the sea surface 511 , the drilling mud is cleaned and then recirculated by the recirculation equipment 508 . The drilling mud is used to cool the drill bit 507 , to carry cuttings from the base of the borehole to the platform 501 , and to balance the hydrostatic pressure in the rock formations. Pressure control equipment such as blow-out preventer (“BOP”) 510 is located on the floating platform 501 and connected to the riser system 516 , making the system a dry BOP system because there is no subsea BOP located at the subsea wellhead 509 . With the pressure control equipment at the platform 501 , the dual barrier requirement may be met by the riser system 516 including an external riser with a nested internal riser.
As shown in FIG. 6 , the external riser 600 surrounds at least a portion of the internal riser 602 . The riser system is shown broken up to be able to include detail on specific sections but it should be appreciated that the riser system maintains fluid integrity from the subsea wellhead to the platform.
A nested riser system requires both the external riser 600 and the internal riser 602 to be held in tension to prevent buckling. Complications may occur in high temperature, deep water environments because different thermal expansion is realized by the external riser 600 and the internal riser 602 due to different temperature exposures-higher temperature drilling fluid versus seawater. To accommodate different tensioning requirements, independent tension devices are provided to tension the external riser 600 and the internal riser 602 at least somewhat or completely independently.
In this embodiment, the external riser 600 is attached at its lower end to the subsea wellhead 509 (shown in FIG. 5 ) using an appropriate connection. For example, the external riser 600 may include a wellhead connector 604 with an integral stress joint as shown. As an example, the wellhead connector 604 may be an external tie back connector. Alternatively, the stress joint may be separate from the wellhead connector 604 . The external riser 600 may or may not include other specific riser joints, such as riser joints with strakes or fairings and splash zone joints 608 . This embodiment also includes a surface BOP 660 . Other appropriate equipment for installation or removal of the external riser 600 and the internal riser 602 , such as a riser running tool 650 and spider 652 may also be located on the platform.
As shown in FIG. 7 , the drilling riser system includes the external drilling riser 700 supported by the dynamic tensioner on the platform. Extending within the external riser 700 is an internal drilling riser 702 . Also included are the external shoulder on the internal drilling riser, the internal shoulder on the external drilling riser 700 , and the annular tensioner. The annular tensioner 712 operates in a similar manner to the annular tensioner described above and the discussion of its operation will not be repeated.
Instead of a production tree as shown in the production system, the external riser and the internal drilling riser of the drilling riser system terminate in a surface drilling wellhead 709 which is connected to a blowout preventer 710 on the drilling platform. Appropriate connections for circulating drilling fluid, such as a diverter (not shown) that accepts the drill string for insertion through the internal drilling riser, are attached to the top of the BOP 710 .
Also included as part of the internal drilling riser is the overshot slip connector 711 using the overshot tubing and PBR 713 . As discussed above, the overshot slip connector allows for the movement of the internal drilling riser relative to the external riser due to thermal expansion. The annular tensioner maintains the internal riser in tension during such movement so as to avoid buckling.
Other embodiments of the present invention can include alternative variations. These and other variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | The riser system of the present invention includes an external production riser for floating structures with interfaces to the dry and subsea wellheads, internal tieback riser with a special lower overshot/slipping connector for elevated temperatures. The seals can be metallic and/or non-metallic dynamic seals. Special centralizing pipe connectors and a special subsea wellhead tubing hanger are also included. This riser system avoids the penalty of pipe within pipe differential thermal growth and the resulting unwanted effects on the floating structure. This is accomplished by allowing an overshot sealing slipping connector to swallow an expanding polished rod as thermal conditions cause pipe elongation axially. When elevated temperatures fall to ambient the opposite occurs as the pipe shrinks axially. Alternatively, a system is possible where a two pipe drilling riser is needed. The internal pipe in this case would be an inner riser rather than a tubing string. | 4 |
TECHNICAL FIELD
The present invention relates to a connection support server and a communication apparatus, and relates to a connection support server and a communication apparatus which enable detection of an apparatus present on a different network in a network comprising a plurality of routers.
BACKGROUND ART
While always-on Internet connections are widespread and various services have appeared accordingly, there is a demand to be able to receive such services in various places at home. Generally speaking, each home has a different home network configuration, and apparatuses used therein are various such as PCs, Internet appliances and the like. However, there is problem that connection settings or connection operations of Internet appliances are difficult for general users who do not have technical knowledge of such a network, and it is also difficult to establish a connection between apparatuses if a configuration of the network, such as a connection mode, router type or the like, is not taken into account.
In order to solve this problem, there is a technique called UPnP (Universal Plug and Play) stipulated by the UPnP Forum, which allows apparatuses within a home network to be interconnected.
By using UPnP, an apparatus within a home network can be automatically searched for and detected by multicasting, and an interconnection with the detected apparatus can be established.
FIG. 17A shows a home network comprising conventional UPnP apparatuses. In FIG. 17A , a modem having a router function, which is rented from an Internet service provider, is connected to a PC, a television and a VCR. FIG. 17B shows a process for detecting an apparatus by UPnP, which is performed in the case of operating the VCR from the PC.
In FIG. 17B , the PC first multicasts, on the network, an apparatus detection request which contains information indicating that a search target is the VCR (step S 201 ). The apparatus detection request is received by all the UPnP apparatuses on the network, and each apparatus determines whether or not the search target is said each apparatus.
The VCR determines that the search target is the VCR, and transmits, to the PC which is a transmission source of the request, an apparatus detection response which contains necessary information for operating the VCR (step S 202 ). By receiving the apparatus detection response, the PC is enabled to operate the VCR.
Using UPnP in this manner enables UPnP apparatuses to be interconnected.
In recent years, however, it has become common that a user connects a router having a wireless function, which the user has purchased, to a modem which functions as a router and which is rented from an Internet service provider, such that each router has apparatuses subordinately connected thereto as shown in FIG. 18A (hereinafter, this type of network configuration will be referred to as a router multistage configuration). FIG. 18B shows a process for detecting an apparatus by UPnP, which is performed when it is desired in FIG. 18A to control a VCR from a PC.
As shown in FIG. 18B , the PC first multicasts, on a network thereof, an apparatus detection request which contains information indicating that a search target is the VCR (step S 301 ). The apparatus detection request is received by all the UPnP apparatuses on the network (a wireless router and a television T 2 in FIG. 18A ), and each apparatus determines whether or not said each apparatus is the search target.
Here, a general commercially available household router is configured, in consideration of security, so as not to transfer a multicast packet to another network. For this reason, in the router multistage configuration as shown in FIG. 18A , the wireless router does not transfer, to a private network N 1 , an apparatus detection request packet received from the PC. Therefore, the VCR which is the search target cannot receive the apparatus detection request, and does not return an apparatus detection response. Accordingly, an apparatus detection response reception waiting time-out occurs in the PC (step S 302 ), and thus the apparatus detection fails (step S 303 ).
As described above, in the router multistage configuration, an apparatus on the same network can be detected using UPnP multicasting. However, an apparatus on a different network cannot be detected.
Conventionally, there are a disclosed network connection apparatus and method (e.g., Patent Document 1) in which a plurality of networks, each of which is independently configured, are connected such that a plurality of devices on the respective networks can be interconnected.
According to the network connection apparatus and method of Patent Document 1, the plurality of networks, each of which is independently configured, are respectively provided with network connection apparatuses, and each network connection apparatus manages information about apparatuses on a corresponding network. The network connection apparatuses exchange such information each other, and this enables apparatuses on different networks to be interconnected.
FIG. 19A shows a router multistage home network in which gateways each including the network connection apparatus of Patent Document 1 are provided. It is assumed here that a network connection apparatus D 1 has already obtained, as access information about a network connection apparatus D 2 , an IP address and a port number of a gateway G 2 , and the network connection apparatus D 2 has already obtained, as access information about the network connection apparatus D 1 , an IP address and a port number of a gateway G 1 . FIG. 19B shows a process for detecting an apparatus by using the network connection apparatus and method of Patent Document 1, which process is performed in the case of operating a VCR from a PC in FIG. 19A .
As shown in FIG. 19B , the network connection apparatus D 1 collects, by multicasting an apparatus detection request, information about apparatuses (television T 1 , VCR) on a private network N 1 (step S 401 ). Similarly, the network connection apparatus D 2 collects, by multicasting an apparatus detection request, information about apparatuses (PC, television T 2 ) on a private network N 2 (step S 402 ).
Next, the PC on the private network N 2 transmits, to the network connection apparatus D 2 , an apparatus detection request which contains information indicating that a search target is the VCR (step S 403 ). Upon receiving the request, the network connection apparatus D 2 sets an IP address and a port number of the gateway G 1 as a transmission destination, and then transfers the apparatus detection request to the network connection apparatus D 1 (step S 404 ). The network connection apparatus D 1 searches the apparatus information obtained at step S 401 for information about the VCR which is the search target contained in the received apparatus detection request, and transmits the information about the VCR to the network connection apparatus D 2 as an apparatus detection response (step S 405 ). Upon receiving the apparatus detection response, the network connection apparatus D 2 transfers the response to the PC which is a transmission source of the request (step S 406 ). In the above manner, the PC is enabled to operate the VCR which is on a different network.
[Patent Document 1] Japanese Laid-Open Patent Publication No. 2004-320741
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
However, the method disclosed in Patent Document 1 needs to meet requirements described below in order to realize an interconnection between apparatuses on different networks.
A first requirement is that networks divided by gateways are each required to have one network connection apparatus.
A second requirement is to input address information about each gateway to each network connection apparatus.
For example, in the case of a home network having a router multistage configuration, a same number of network connection apparatuses as a number of provided routers (i.e., as a number of networks divided by the routers) are necessary in order to meet the first requirement. This causes a problem that a cost for the user becomes a substantial amount.
Also, in order to meet the second requirement, it is necessary for the user to manually set, for all the network connection apparatuses, address information about all the routers, and thus the general user who does not have enough network knowledge is required to do difficult troublesome work. A conceivable manner to eliminate the necessity for the user to do such work is to mount, on each router, a network connection apparatus which has a mechanism for exchanging address information, or to provide routers each having a mechanism for exchanging router address information. However, replacing all the routers in the home network with dedicated routers still causes the problem that the cost for the user becomes a substantial amount.
Therefore, an object of the present invention is, in view of the above-described problem, to provide a communication apparatus which allows a network to be configured with a low cost and a simple process.
Solution to the Problems
The present invention is directed to a communication apparatus having a connection support server function, which is, in a network comprising a plurality of subnetworks connected via a plurality of NAT devices, connected to an arbitrary subnetwork in the network and which has an established communication path with a communication apparatus connected to a different subnetwork from the subnetwork to which the communication apparatus having the connection support server function is connected. In order to achieve the above object, the communication apparatus of the present invention comprises: a relay request transfer section for, when receiving from an arbitrary communication apparatus a relay request for an apparatus detection request, transferring to another communication apparatus the relay request for the apparatus detection request; and an apparatus detection response transfer section for, when receiving an apparatus detection response, transferring the received apparatus detection response to the communication apparatus which is a transmission source of the relay request. When receiving the relay request for the apparatus detection request, the relay request transfer section transfers the relay request for the apparatus detection request, to an arbitrary communication apparatus connected to a different subnetwork from a subnetwork to which the communication apparatus which is the transmission source of the relay request is connected. The apparatus detection response transfer section has the connection support server function for, when receiving the apparatus detection response from the communication apparatus to which the relay request for the apparatus detection request has been transferred, transferring the apparatus detection response to the communication apparatus which is a transmission source of the apparatus detection request.
This enables the communication apparatus, which is the transmission source of the apparatus detection request, to detect a communication apparatus present on a different subnetwork.
Preferably, the communication apparatus further comprises: an apparatus detection request transmission section for multicasting or broadcasting, on the subnetwork thereof, an apparatus detection request for a desired communication apparatus; a relay request transmission section for transmitting a relay request for the apparatus detection request, to the communication apparatus on the different subnetwork; and an apparatus detection response receiving section for receiving an apparatus detection response. The apparatus detection request transmission section transmits, on the subnetwork thereof, the apparatus detection request for the desired communication apparatus. In the case where the apparatus detection response receiving section does not receive the apparatus detection response to the apparatus detection request, the relay request transmission section transmits the relay request for the apparatus detection request, to the communication apparatus on the different subnetwork. The apparatus detection response receiving section receives the apparatus detection response to the relay request, thereby detecting the desired communication apparatus.
This enables the communication apparatus of the present invention to detect a desired communication apparatus within the network.
When receiving, from the communication apparatus on the different subnetwork, the relay request for the apparatus detection request, the relay request transfer section performs an apparatus detection on the subnetwork thereof, by multicasting or broadcasting the apparatus detection request, and transfers the relay request for the apparatus detection request, to an arbitrary communication apparatus on all other subnetworks.
This allows the communication apparatus of the present invention to omit steps in which the apparatus detection request is relayed, on the subnetwork of the communication apparatus, to an arbitrary communication apparatus and the arbitrary apparatus on the subnetwork performs multicasting or broadcasting. Accordingly, a time consumed for the search can be reduced.
When the relay request transfer section has received, on the subnetwork thereof, a multicasted or broadcasted apparatus detection request from a communication apparatus on the subnetwork, the relay request transfer section transmits a relay request for the apparatus detection request, to an arbitrary communication apparatus on the different subnetwork.
This enables the communication apparatus of the present invention to perform an apparatus detection on the different subnetwork at the same time as a communication apparatus, which is present on the subnetwork of the communication apparatus of the present invention and which has multicasted or broadcasted the apparatus detection request on the subnetwork, waits for a response to the apparatus detection request. Accordingly, a time to be consumed when an apparatus to detect is not present on the subnetwork, can be reduced.
The relay request transfer section stores information about communication apparatuses, and when receiving the relay request for the apparatus detection request, the relay request transfer section determines, based on the information about the communication apparatuses, a communication apparatus to which the relay request is to be transferred.
This enables the communication apparatus of the present invention to always cause only an apparatus having a high processing capability to multicast or broadcast the apparatus detection request, and thereby prevent a processing load from being imposed on a communication apparatus having a low processing capability. This also allows the communication apparatus of the present invention to always request a different communication apparatus to multicast or broadcast the apparatus detection request, in order for the processing to be performed in a dispersed manner. As a result, stability of the network can be obtained.
The communication apparatus further comprises a relay rejection response receiving section for receiving a rejection response to the relay request for the apparatus detection request. When receiving the rejection response, the relay rejection response receiving section transfers the relay request for the apparatus detection request, to a different communication apparatus from a communication apparatus which is a transmission source of the rejection response, the different communication apparatus existing on a same subnetwork as that of the communication apparatus which is the transmission source of the rejection response.
This allows the communication apparatus of the present invention to, in the case where a communication apparatus which is requested to relay the apparatus detection request is unable to multicast or broadcast the apparatus detection request due to a load imposed thereon, request another communication apparatus, on which a processing load is not imposed, to relay the apparatus detection request. This prevents the communication apparatus from becoming incapable of performing processing.
The present invention is also directed to a communication apparatus which is, in a network comprising a plurality of subnetworks connected via a plurality of NAT devices, connected to an arbitrary subnetwork in the network and which has an established communication path with a communication apparatus which has a communication path connected to a communication apparatus on the network and which has a connection support server function. In order to achieve the above object, the communication apparatus of the present invention comprises: an apparatus detection request transmission section for multicasting or broadcasting, on the subnetwork thereof, an apparatus detection request for a desired communication apparatus; a relay request transmission section for transmitting a relay request for the apparatus detection request, to the communication apparatus having the connection support server function; and an apparatus detection response receiving section for receiving an apparatus detection response. The apparatus detection response receiving section receives the apparatus detection response from the desired communication apparatus or from the communication apparatus having the connection support server function, thereby detecting the desired communication apparatus.
This allows the communication apparatus of the present invention to detect a communication apparatus on a different subnetwork.
In the case where the apparatus detection response receiving section does not receive the apparatus detection response to the apparatus detection request, the relay request transmission section transmits the relay request for the apparatus detection request, to the communication apparatus having the connection support server function.
This allows the communication apparatus of the present invention to, only when a desired communication apparatus is not present on the subnetwork of the communication apparatus of the present invention, perform the relay request for the apparatus detection request, whereby an unnecessary packet transmission on the network can be prevented.
At the same time as the apparatus detection request transmission section multicasts or broadcasts the apparatus detection request on the subnetwork thereof, the relay request transmission section transmits the relay request for the apparatus detection request, to the communication apparatus having the connection support server function.
This enables the communication apparatus of the present invention to, in the case where a desired communication apparatus is not present on the subnetwork of the communication apparatus of the present invention, perform an apparatus detection on a different subnetwork at the same time as waiting for a response reception. Accordingly, a time, which is consumed until the desired communication apparatus is detected, can be reduced.
The communication apparatus further comprises a relay request processing section for multicasting or broadcasting an apparatus detection request on the subnetwork thereof when receiving, from the communication apparatus having the connection support server function, a relay request for the apparatus detection request. When the apparatus detection response receiving section has received the apparatus detection response, the relay request processing section transfers the received apparatus detection response to the communication apparatus having the connection support server function.
This allows the communication apparatus of the present invention to perform detection of a communication apparatus on the subnetwork of the communication apparatus of the present invention, by proxy for a communication apparatus on another subnetwork, and transfer the response via the communication apparatus having the connection support server function. This enables the communication apparatus which is a transmission source of the relay request to detect the communication apparatus present on a different subnetwork.
The communication apparatus further comprises a relay rejection response transmission section for, when the relay request processing section has received, from the communication apparatus having the connection support server function, the relay request for the apparatus detection request and determined that a processing capability of the relay request processing section is insufficient for multicasting or broadcasting the apparatus detection request on the subnetwork thereof, transmitting, to the communication apparatus having the connection support server function, a rejection response to the relay request for the apparatus detection request.
This allows, in the case where the communication apparatus of the present invention is, when receiving the relay request for the apparatus detection request, unable to multicast or broadcast the apparatus detection request due to a processing load imposed thereon, the communication apparatus to reject the request. This prevents the communication apparatus from becoming incapable of performing processing.
The above-described series of processing sequences performed by the communication apparatuses may be implemented as methods to be executed by the communication apparatuses. Further, the present invention may be a storage medium for storing software in which the methods are implemented.
EFFECT OF THE INVENTION
The present invention enables detection of a desired communication apparatus whichever network the communication apparatus belongs to in a router multistage home network, and prevents misplacement of a communication apparatus even if a user does not have special knowledge. Further, routers to be used in the home network may be commercially available routers, and only one apparatus on the home network is required to have a connection support server function. Therefore, a cost for the user can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exemplary configuration of an entire system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing an exemplary configuration of a connection support server 001 according to the first embodiment of the present invention.
FIG. 3A is a block diagram showing an exemplary configuration of a communication apparatus 101 according to the first embodiment of the present invention.
FIG. 3B is a block diagram showing an exemplary configuration of a communication apparatus 102 according to the first embodiment of the present invention.
FIG. 3C is a block diagram showing an exemplary configuration of a communication apparatus 201 according to the first embodiment of the present invention.
FIG. 3D is a block diagram showing an exemplary configuration of a communication apparatus 202 according to the first embodiment of the present invention.
FIG. 4 shows a processing sequence, of the first embodiment of the present invention, for detecting the communication apparatus 201 connected to a subordinate network from the communication apparatus 101 connected to a superordinate network.
FIG. 5 shows a processing sequence, of the first embodiment of the present invention, in which the connection support server 001 transmits, at the same time as the connection support server 001 receives an apparatus detection request from the communication apparatus 101 on a network of the server 001 , a relay request to an arbitrary communication apparatus on a different network.
FIG. 6 shows a processing sequence, of the first embodiment of the present invention, for detecting the communication apparatus 102 connected to a superordinate network from the communication apparatus 202 connected to a subordinate network.
FIG. 7 shows a processing sequence, of the first embodiment of the present invention, in which the connection support server 001 multicasts, on a network thereof, an apparatus detection request to communication apparatuses at the same time as the connection support server 001 receives a relay request for an apparatus detection request from the communication apparatus 202 on a different network.
FIG. 8 shows an exemplary configuration of an entire system according to a second embodiment of the present invention.
FIG. 9A is a block diagram showing an exemplary configuration of a communication apparatus 301 according to the second embodiment of the present invention.
FIG. 9B is a block diagram showing an exemplary configuration of a communication apparatus 302 according to the second embodiment of the present invention.
FIG. 10 shows a processing sequence, of the second embodiment of the present invention, for detecting the communication apparatus 201 connected to a subordinate network from the communication apparatus 101 connected to a superordinate network.
FIG. 11 shows a processing sequence, of the second embodiment of the present invention, for detecting the communication apparatus 102 connected to a superordinate network from the communication apparatus 301 connected to a subordinate network.
FIG. 12 shows an exemplary configuration of an entire system according to a third embodiment of the present invention.
FIG. 13 shows a processing sequence, of the third embodiment of the present invention, for detecting, from the communication apparatus 202 connected to a subordinate network, the communication apparatus 302 connected to a different subordinate network.
FIG. 14 shows an exemplary configuration of an entire system according to a fourth embodiment of the present invention.
FIG. 15 is a block diagram showing an exemplary configuration of a communication apparatus 401 according to the fourth embodiment of the present invention.
FIG. 16 shows a processing sequence, of the fourth embodiment of the present invention, for detecting the communication apparatus 302 connected to a private network from the communication apparatus 401 connected to a global network.
FIG. 17A shows a home network comprising conventional UPnP apparatuses.
FIG. 17B shows a process for detecting an UPnP apparatus in a conventional home network.
FIG. 18 shows a conventional router multistage home network.
FIG. 18B shows a process for detecting an UPnP apparatus in a conventional home network.
FIG. 19A shows a router multistage home network in which gateways each including a network connection apparatus of Patent Document 1 are provided.
FIG. 19B shows a processing sequence for performing an apparatus detection by using a network connection apparatus and method of Patent Document 1.
DESCRIPTION OF THE REFERENCE CHARACTERS
00 global network
00 , 02 private network
001 server
100 , 200 , 300 router
101 , 202 , 301 , 401 communication apparatus
102 , 201 , 302 communication apparatus
0011 relay request transfer section
0012 apparatus detection response transfer section
0013 relay rejection response receiving section
0014 communication path information storage section
0015 communication section
1011 , 2021 , 3011 , 4011 apparatus detection request transmission section
1012 , 2022 , 3012 , 4012 apparatus detection response receiving section
1013 , 2023 , 3013 , 4013 relay request transmission section
1014 , 2024 , 3014 , 4014 relay request processing section
1015 , 2025 , 3015 , 4015 communication section
1021 , 2011 , 3021 apparatus detection request receiving section
1022 , 2012 , 3022 apparatus detection response transmission section
1023 , 2013 , 3023 communication section
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an exemplary configuration of an entire system according to the first embodiment of the present invention.
As shown in FIG. 1 , a global network 00 and a private network 01 are connected via a router 100 . The router 100 has a global IP address [IPW 100 ] as a WAN address, and a private IP address [IPL 100 ] as a LAN address.
The private network 01 and a private network 02 are connected via a router 200 . The router 200 has a private IP address [IPW 200 ] as a WAN address and a private IP address [IPL 200 ] as a LAN address.
A communication apparatus 101 having a private IP address [IPL 101 ] and a communication apparatus 102 having a private IP address [IPL 102 ] are connected to the private network 01 .
A communication apparatus 201 having a private IP address [IPL 201 ] and a communication apparatus 202 having a private IP address [IPL 202 ] are connected to the private network 02 .
A connection support server 001 having a private IP address [IPL 001 ] is connected to the private network 01 . The connection support server 001 has established communication paths through which the connection support server 001 can interactively communicate with all the communication apparatuses connected to the private network 01 and the private network 02 .
FIG. 2 is a block diagram showing an exemplary configuration of the connection support server 001 according to the first embodiment of the present invention. FIG. 3A is a block diagram showing an exemplary configuration of the communication apparatus 101 according to the first embodiment of the present invention. FIG. 3B is a block diagram showing an exemplary configuration of the communication apparatus 102 according to the first embodiment of the present invention. FIG. 3C is a block diagram showing an exemplary configuration of the communication apparatus 201 according to the first embodiment of the present invention. FIG. 3D is a block diagram showing an exemplary configuration of the communication apparatus 202 according to the first embodiment of the present invention.
As shown in FIG. 2 , the connection support server 001 comprises: a relay request transfer section 0011 for, when receiving from an arbitrary communication apparatus a request to relay an apparatus detection request, transferring to a different communication apparatus the request to relay the apparatus detection request; an apparatus detection response transfer section 0012 for, when receiving an apparatus detection response, transferring the apparatus detection response to the apparatus which is a transmission source of the relay request; a relay rejection response receiving section 0013 for receiving a rejection response to the relay request for the apparatus detection request, from the communication apparatus to which the relay request has been transferred; a communication path information storage section 0014 for storing information about communication paths to all the communication apparatuses; and a communication section 0015 for performing all the communications. Mounting these functional sections on an arbitrary Internet appliance eliminates the necessity to have a dedicated apparatus which functions as the connection support server, thereby reducing a cost for a user. Note that, the connection support server 001 may not necessarily have the relay rejection response receiving section 0013 .
As shown in FIG. 3A , the communication apparatus 101 comprises: an apparatus detection request transmission section 1011 for multicasting or broadcasting, on a network thereof, an apparatus detection request for an apparatus which is desired to establish a communication with the communication apparatus 101 ; a relay request transmission section 1013 for transmitting, to the connection support server 001 , a request to relay the apparatus detection request; an apparatus detection response receiving section 1012 for receiving an apparatus detection response; a relay request processing section 1014 for, when receiving from the connection support server 001 a request to relay an apparatus detection request, multicasting or broadcasting the apparatus detection request on the network of the communication apparatus 101 ; and a communication section 1015 for performing all the communications. The communication apparatus 101 is, for example, a PC or remote controller for operating another apparatus.
As shown in FIG. 3B , the communication apparatus 102 comprises: an apparatus detection request receiving section 1021 for receiving an apparatus detection request which is multicasted or broadcasted on a network thereof, and determining whether or not a search target contained in the received apparatus detection request is the communication apparatus 102 ; an apparatus detection response transmission section 1022 for transmitting an apparatus detection response when the search target is the communication apparatus 102 ; and a communication section 1023 for performing all the communications. The communication apparatus 102 is, for example, a television or VCR which is operated by another apparatus.
As shown in FIG. 3C , the communication apparatus 201 comprises: an apparatus detection request receiving section 2011 for receiving an apparatus detection request which is multicasted or broadcasted on a network thereof, and determining whether or not a search target contained in the received apparatus detection request is the communication apparatus 201 ; an apparatus detection response transmission section 2012 for transmitting an apparatus detection response when the search target is the communication apparatus 201 ; and a communication section 2013 for performing all the communications. The communication apparatus 201 is, for example, a television or VCR which is operated by another apparatus.
As shown in FIG. 3D , the communication apparatus 202 comprises: an apparatus detection request transmission section 2021 for multicasting or broadcasting, on a network thereof, an apparatus detection request for an apparatus which is desired to establish a communication with the communication apparatus 202 ; a relay request transmission section 2023 for transmitting, to the connection support server 001 , a request to relay the apparatus detection request; an apparatus detection response receiving section 2022 for receiving an apparatus detection response; a relay request processing section 2024 for, when receiving from the connection support server 001 a request to relay an apparatus detection request, multicasting or broadcasting the apparatus detection request on the network of the communication apparatus 202 ; and a communication section 2025 for performing all the communications. The communication apparatus 202 is, for example, a PC or remote controller for operating another apparatus.
Described below in the present embodiment is an apparatus detection process which is performed in the case where the connection support server 001 is connected to the private network 01 .
Described first with reference to FIG. 4 is a process in which the communication apparatus 101 on the private network 01 detects the communication apparatus 201 on the private network 02 .
The apparatus detection request transmission section 1011 of the communication apparatus 101 multicasts via the communication section 1015 , on the private network 01 to which the communication apparatus 101 is connected, an apparatus detection request which designates the communication apparatus 201 as a search target (step S 701 ). Since the communication apparatus 201 is not present on the private network 01 and the router 200 does not transfer the apparatus detection request to the private network 02 , a reception time-out occurs in the apparatus detection response receiving section 1012 for an apparatus detection response to be received from the communication apparatus 201 (step S 702 ). Thus, the apparatus detection fails (step S 703 ).
When the apparatus detection fails on the network of the communication apparatus 101 , the relay request transmission section 1013 of the communication apparatus 101 transmits, to the relay request transfer section 0011 of the connection support server 001 via the communication section 1015 , a request to relay the apparatus detection request (step S 704 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus present on the network of the connection support server 001 , the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the network of the connection support server 001 (here, only the private network 02 ) (in this case, the communication apparatus 202 is selected), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 705 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 2024 of the communication apparatus 202 extracts the search target (communication apparatus 201 ) from the relay request for the apparatus detection request (step S 706 ), and multicasts, on the private network 02 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 2021 via the communication section 2025 (step S 707 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 2011 of the communication apparatus 201 determines that the communication apparatus 201 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 2012 to the relay request processing section 2024 of the communication apparatus 202 via the communication section 2013 (step S 708 ).
Upon receiving the apparatus detection response, the relay request processing section 2024 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 709 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 1012 of the communication apparatus 101 (step S 710 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 1012 of the communication apparatus 101 , the apparatus detection succeeds in detecting the communication apparatus 201 on the different private network (step S 711 ).
Here, at step S 701 , at the same time as the communication apparatus 101 multicasts, on the network thereof, the apparatus detection request from the apparatus detection request transmission section 1011 , the communication apparatus 101 may transmit, from the relay request transmission section 1013 to the relay request transfer section 0011 of the connection support server 001 , the relay request for the apparatus detection request.
Accordingly, when an apparatus to detect is not present on the network of the communication apparatus 101 , the apparatus detection can be performed on a different network at the same time as the communication apparatus 101 waits for a response to be received. This allows a time, which is consumed until the apparatus is detected, to be reduced.
Further, at step S 701 , at the same time as the connection support server 001 receives the apparatus detection request multicasted from the communication apparatus 101 on the network of the server 001 , the connection support server 001 may transmit the relay request for the apparatus detection request, to an arbitrary apparatus on a different network. Operations performed at the time will hereinafter be described with reference to FIG. 5 .
As shown in FIG. 5 , the apparatus detection request transmission section 1011 of the communication apparatus 101 multicasts via the communication section 1015 , on the private network 01 to which the communication apparatus 101 is connected, an apparatus detection request designating the communication apparatus 201 as a search target (step S 801 ). Here, since the communication apparatus 201 is not present on the private network 01 and the router 200 does not transfer the apparatus detection request to the private network 02 , the apparatus detection response receiving section 1012 enters a state of waiting for an apparatus detection response to be received from the communication apparatus 201 .
Here, when the relay request transfer section 0011 of the connection support server 001 receives, at step S 801 , the apparatus detection request multicasted by the communication apparatus present on the network of the connection support server 001 , the relay request transfer section 0011 immediately selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the network of the connection support server 001 (here, only the private network 02 ) (in this case, the communication apparatus 202 is selected), with which arbitrary apparatus a connection is to be established, and then the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , a relay request for the apparatus detection request (step S 802 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 2024 of the communication apparatus 202 extracts the search target (communication apparatus 201 ) from the relay request for the apparatus detection request (step S 803 ), and multicasts, on the private network 02 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 2021 via the communication section 2025 (step S 804 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 2011 of the communication apparatus 201 determines that the communication apparatus 201 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 2012 to the relay request processing section 2024 of the communication apparatus 202 via the communication section 2013 (step S 805 ).
Upon receiving the apparatus detection response, the relay request processing section 2024 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 806 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 1012 of the communication apparatus 101 (step S 807 ).
By receiving, from the connection support server 001 , the apparatus detection response at the apparatus detection response receiving section 1012 which is in the state of waiting for the apparatus detection response to be received from the communication apparatus 201 , the apparatus detection succeeds in detecting the communication apparatus 201 on the different private network (step S 808 ).
As described above, at the same time as an apparatus on a network waits for a response to an apparatus detection request multicasted on the network, apparatus detection can be performed on a different network. This allows a time, which is consumed when an apparatus to detect is not present on the network, to be reduced.
Described next with reference to FIG. 6 is a process in which the communication apparatus 202 on the private network 02 detects the communication apparatus 102 on the private network 01 .
As shown in FIG. 6 , the apparatus detection request transmission section 2021 of the communication apparatus 202 multicasts via the communication section 2025 , on the private network 02 to which the communication apparatus 202 is connected, an apparatus detection request which designates the communication apparatus 102 as a search target (step S 901 ). Here, since the communication apparatus 102 is not present on the private network 02 and the router 200 does not transfer the apparatus detection request to the private network 01 , a reception time-out occurs in the apparatus detection response receiving section 2022 for an apparatus detection response to be received from the communication apparatus 102 (step S 902 ). Thus, the apparatus detection fails (step S 903 ).
When the apparatus detection fails on the network of the communication apparatus 202 , the relay request transmission section 2023 of the communication apparatus 202 transmits via the communication section 2025 to the relay request transfer section 0011 of the connection support server 001 , a request to relay the apparatus detection request (step S 904 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus present on a different network, the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 02 (here, only the private network 01 ) (in this case, the communication apparatus 101 is selected), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 905 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 1014 of the communication apparatus 101 extracts the search target (communication apparatus 102 ) from the relay request for the apparatus detection request (step S 906 ), and multicasts, on the private network 01 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 1011 via the communication section 1015 (step S 907 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 1021 of the communication apparatus 102 determines that the communication apparatus 102 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 1022 to the relay request processing section 1014 of the communication apparatus 101 via the communication section 1023 (step S 908 ).
Upon receiving the apparatus detection response, the relay request processing section 1014 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 909 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 2022 of the communication apparatus 202 (step S 910 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 2022 of the communication apparatus 202 , the apparatus detection succeeds in detecting the communication apparatus 102 on the different private network (step S 911 ).
Upon receiving, at step S 904 , the relay request for the apparatus detection request, the connection support server 001 may multicast the apparatus detection request on the network of the connection support server 001 , instead of transferring the relay request to the arbitrary apparatus on the network. Operations performed at the time will be described with reference to FIG. 7 .
Processing performed at steps S 1001 to S 1004 in FIG. 7 is the same as that performed at steps S 901 to S 904 in FIG. 6 .
Upon receiving the relay request for the apparatus detection request at step S 1004 , the relay request transfer section 0011 of the connection support server 001 multicasts, on the network of the connection support server 001 via the communication section 0015 , the apparatus detection request for the apparatus which is the search target contained in the relay request (i.e., the communication apparatus 102 ) (step S 1005 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 1021 of the communication apparatus 102 determines that the communication apparatus 102 is designated as the search target, and then transmits, via the communication section 1023 , an apparatus detection response from the apparatus detection response transmission section 1022 to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 1006 ).
Upon receiving the apparatus detection response, the apparatus detection response transfer section 0012 transmits, via the communication section 0015 , the apparatus detection response to the apparatus detection response receiving section 2022 of the communication apparatus 202 which is a transmission source of the relay request (step S 1007 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 2022 of the communication apparatus 202 , the apparatus detection succeeds in detecting the communication apparatus 102 on the different private network (step S 1008 ).
As described above, the connection support server 001 multicasts the apparatus detection request on the network of the connection support server 001 , instead of transferring the relay request to an arbitrary apparatus on the network. This omits the steps in which the apparatus detection request is relayed to the arbitrary apparatus on the network of the connection support server 001 and the arbitrary apparatus performs multicasting. Accordingly, a time consumed for the search can be reduced.
Note that, the relay request transfer section 0011 of the connection support server 001 which has received, from the communication apparatus on the different network at step S 904 of FIG. 6 , the relay request for the apparatus detection request, selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 02 (here, only the private network 01 ) (in this case, the communication apparatus 101 is selected), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request. Here, the relay request may be always transmitted to the same communication apparatus. For example, by always causing an apparatus having a high processing capability to multicast the apparatus detection request, such processing load can be prevented from being imposed on an apparatus having a low processing capability.
Further, the relay request transfer section 0011 of the connection support server 001 which has received, from the communication apparatus on the different network, the relay request for the apparatus detection request may transmit the relay request for the apparatus detection request, to a different communication apparatus each time the relay request transfer section 0011 transmits the relay request. As a result, the multicasting of the apparatus detection request can be performed in a dispersed manner, whereby stability of the network is obtained.
The communication apparatus, which has received the relay request at step S 705 of FIG. 4 , step S 802 of FIG. 5 or step S 905 of FIG. 6 , may transmit, in consideration of processing load thereon, a relay rejection response from a relay rejection response transmission section (not shown) to the relay rejection response receiving section 0013 of the connection support server 001 . The relay rejection response receiving section 0013 , which has received the relay rejection response, retransmits the relay request to a communication apparatus which is stored in the communication path information storage section 0014 and which is different from the apparatus which is a transmission source of the relay rejection response. This prevents the apparatus from becoming incapable of performing processing due to performing the relay processing.
Used as a message of an apparatus detection request may be an M-SEARCH request stipulated by UPnP, or may be a message stipulated by a different protocol.
The transmission manner of the apparatus detection request is not limited to multicasting. The transmission manner may be broadcasting or any other manner of data transmission.
The configuration described in the present embodiment is merely an example, and the present embodiment is not limited thereto.
For example, in the case where the connection support server 001 is connected to the private network 02 , the communication apparatus 201 can be detected from the communication apparatus 101 , and also the communication apparatus 102 can be detected from the communication apparatus 202 , by performing the same processing as described above.
It is assumed in the present embodiment that all the communication apparatuses each have a communication path established with the connection support server 001 . However, the present embodiment is not limited thereto. As long as there is, on a private network, at least one communication apparatus which has a communication path established with the connection support server 001 , even a communication apparatus which does not have a communication path established with the connection support server 001 can be detected by causing the at least one communication apparatus having the established communication path to perform the relaying in accordance with the processing sequence described in the present embodiment.
Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 8 shows an exemplary configuration of an entire system according to the second embodiment of the present invention.
As shown in FIG. 8 , the global network 00 and the private network 01 are connected via the router 100 . The router 100 has the global IP address [IPW 100 ] as a WAN address and the private IP address [IPL 100 ] as a LAN address.
Also, the private network 01 and the private network 02 are connected via the router 200 . The router 200 has the private IP address [IPW 200 ] as a WAN address and the private IP address [IPL 200 ] as a LAN address.
Further, the private network 02 and a private network 03 are connected via a router 300 . The router 300 has a private IP address [IPW 300 ] as a WAN address and a private IP address [IPL 300 ] as a LAN address.
The communication apparatus 101 having the private IP address [IPL 101 ] and the communication apparatus 102 having the private IP address [IPL 102 ] are connected to the private network 01 .
The communication apparatus 201 having the private IP address [IPL 201 ] and the communication apparatus 202 having the private IP address [IPL 202 ] are connected to the private network 02 .
A communication apparatus 301 having a private IP address [IPL 301 ] and a communication apparatus 302 having a private IP address [IPL 302 ] are connected to the private network 03 .
The connection support server 001 having the private IP address [IPL 001 ] is also connected to the private network 02 . The connection support server 001 has established communication paths through which the connection support server 001 can interactively communicate with all the communication apparatuses connected to the private networks 01 , 02 and 03 .
Block diagrams showing the configurations of the connection support server 001 and the communication apparatuses 101 , 102 , 201 and 202 are the same as those described in the first embodiment.
FIG. 9A is a block diagram showing an exemplary configuration of the communication apparatus 301 according to the second embodiment of the present invention. FIG. 9B is a block diagram showing an exemplary configuration of the communication apparatus 302 according to the second embodiment of the present invention.
As shown in FIG. 9A , the communication apparatus 301 comprises: an apparatus detection request transmission section 3011 for multicasting, on a network thereof, an apparatus detection request for an apparatus which is desired to establish a communication with the communication apparatus 301 ; an apparatus detection response receiving section 3012 for receiving an apparatus detection response; a relay request transmission section 3013 for transmitting, to the connection support server 001 , a request to relay the apparatus detection request; a relay request processing section 3014 for, when receiving from the connection support server 001 a request to relay an apparatus detection request, multicasting the apparatus detection request on the network of the communication apparatus 301 ; and a communication section 3015 for performing all the communications. The communication apparatus 301 is, for example, a PC or remote controller for operating another apparatus.
As shown in FIG. 9B , the communication apparatus 302 comprises: an apparatus detection request receiving section 3021 for receiving an apparatus detection request which is multicasted on a network thereof, and determining whether or not a search target contained in the received apparatus detection request is the communication apparatus 302 ; an apparatus detection response transmission section 3022 for transmitting an apparatus detection response when the search target is the communication apparatus 302 ; and a communication section 3023 for performing all the communications. The communication apparatus 302 is, for example, a television or VCR which is operated by another apparatus.
Described below in the present embodiment is an apparatus detection process which is performed in the case where the connection support server 001 is connected to the private network 02 .
Described first with reference to FIG. 10 is a process in which the communication apparatus 101 on the private network 01 detects the communication apparatus 201 on the private network 02 .
The apparatus detection request transmission section 1011 of the communication apparatus 101 multicasts via the communication section 1015 , on the private network 01 to which the communication apparatus 101 is connected, an apparatus detection request which designates the communication apparatus 201 as a search target (step S 1301 ). Here, since the communication apparatus 201 is not present on the private network 01 and the router 200 does not transfer the apparatus detection request to the private network 02 , a reception time-out occurs in the apparatus detection response receiving section 1012 for an apparatus detection response to be received from the communication apparatus 201 (step S 1302 ). Thus, the apparatus detection fails (step S 1303 ).
When the apparatus detection fails on the network of the communication apparatus 101 , the relay request transmission section 1013 of the communication apparatus 101 transmits, to the relay request transfer section 0011 of the connection support server 001 via the communication section 1015 , a request to relay the apparatus detection request (step S 1304 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus 101 present on a different network (private network 01 ), the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 01 (here, the private network 02 and the private network 03 ) (in this case, the communication apparatus 202 and the communication apparatus 301 are selected), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 1305 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 2024 of the communication apparatus 202 extracts the search target (communication apparatus 201 ) from the relay request for the apparatus detection request (step S 1306 ), and multicasts, on the private network 02 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 2021 via the communication section 2025 (step S 1307 ).
Similarly, Upon receiving the relay request from the connection support server 001 , the relay request processing section 3014 of the communication apparatus 301 extracts the search target (communication apparatus 201 ) from the relay request for the apparatus detection request (step S 1308 ), and multicasts, on the private network 03 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 3011 via the communication section 3015 (step S 1309 ).
Here, since the communication apparatus 201 is not present on the private network 03 , and the router 300 does not transfer the apparatus detection request to the private network 02 , a reception time-out occurs for an apparatus detection response to be received from the communication apparatus 201 (step S 1310 ).
Upon receiving the apparatus detection request multicasted by the communication apparatus 202 , the apparatus detection request receiving section 2011 of the communication apparatus 201 determines that the communication apparatus 201 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 2012 to the relay request processing section 2024 of the communication apparatus 202 via the communication section 2013 (step S 1311 ).
Upon receiving the apparatus detection response, the relay request processing section 2024 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 1312 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 1012 of the communication apparatus 101 (step S 1313 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 1012 of the communication apparatus 101 , the apparatus detection succeeds in detecting the communication apparatus 201 on the different private network (step S 1314 ).
Here, at step S 1301 , at the same time as the communication apparatus 101 multicasts, on the network thereof, the apparatus detection request from the apparatus detection request transmission section 1011 , the communication apparatus 101 may transmit, from the relay request transmission section 1013 to the relay request transfer section 0011 of the connection support server 001 , the relay request for the apparatus detection request. Accordingly, when an apparatus to detect is not present on the network of the communication apparatus 101 , the apparatus detection can be performed on different networks at the same time as the communication apparatus 101 waits for a response to be received. This allows a time, which is consumed until the apparatus is detected, to be reduced.
Upon receiving, at step S 1304 , the relay request for the apparatus detection request, the connection support server 001 may multicast the apparatus detection request on the network of the connection support server 001 , instead of transferring the relay request to the arbitrary apparatus on the network. Since operations performed at the time are the same as the processing shown in FIG. 7 of the first embodiment, a description thereof will be omitted. In the above manner, the steps in which the apparatus detection request is relayed to the arbitrary apparatus on the network of the connection support server 001 and the apparatus performs multicasting, can be omitted. Accordingly, a time consumed for the search can be reduced.
Described next with reference to FIG. 11 is a process in which the communication apparatus 301 on the private network 03 detects the communication apparatus 102 on the private network 01 .
As shown in FIG. 11 , the apparatus detection request transmission section 3011 of the communication apparatus 301 multicasts via the communication section 3015 , on the private network 03 to which the communication apparatus 301 is connected, an apparatus detection request which designates the communication apparatus 102 as a search target (step S 1401 ). Here, since the communication apparatus 102 is not present on the private network 03 , and the router 200 does not transfer the apparatus detection request to the private network 02 , a reception time-out occurs in the apparatus detection response receiving section 3012 for an apparatus detection response to be received from the communication apparatus 102 (step S 1402 ). Thus, the apparatus detection fails (step S 1403 ).
When the apparatus detection fails on the network of the communication apparatus 301 , the relay request transmission section 3013 of the communication apparatus 301 transmits, to the relay request transfer section 0011 of the connection support server 001 via the communication section 3015 , a request to relay the apparatus detection request (step S 1404 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus 301 present on a different network (private network 03 ), the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 03 (here, the private network 01 and the private network 02 ) (in this case, the communication apparatus 101 and the communication apparatus 202 are selected), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 1405 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 1014 of the communication apparatus 101 extracts the search target (communication apparatus 102 ) from the relay request for the apparatus detection request (step S 1406 ), and multicasts, on the private network 01 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 1011 via the communication section 1015 (step S 1407 ).
Similarly, Upon receiving the relay request from the connection support server 001 , the relay request processing section 2024 of the communication apparatus 202 extracts the search target (communication apparatus 102 ) from the relay request for the apparatus detection request (step S 1408 ), and multicasts, on the private network 02 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 2021 via the communication section 2025 (step S 1409 ).
Here, since the communication apparatus 102 is not present on the private network 02 and the router 200 does not transfer the apparatus detection request to the private network 01 , a reception time-out occurs for an apparatus detection response to be received from the communication apparatus 102 (step S 1410 ).
Upon receiving the apparatus detection request multicasted by the communication apparatus 101 , the apparatus detection request receiving section 1021 of the communication apparatus 102 determines that the communication apparatus 102 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 1022 to the relay request processing section 1014 of the communication apparatus 101 via the communication section 1023 (step S 1411 ).
Upon receiving the apparatus detection response, the relay request processing section 1014 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 1412 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 3012 of the communication apparatus 301 (step S 1413 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 3012 of the communication apparatus 301 , the apparatus detection succeeds in detecting the communication apparatus 102 on the different private network (step S 1414 ).
Note that, when the relay request transfer section 0011 of the connection support server 001 receives, from the communication apparatus on the different network at step S 1404 of FIG. 11 , the relay request for the apparatus detection request, the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 03 (here, the private network 01 and the private network 02 ) (in this case, the communication apparatus 101 and the communication apparatus 202 are selected), and then transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request. Here, the relay request may be always transmitted to the same communication apparatus. For example, by always causing an apparatus having a high processing capability to multicast the apparatus detection request, a time consumed for the search can be reduced.
Further, the relay request transfer section 0011 of the connection support server 001 which has received, from the communication apparatus on the different network, the relay request for the apparatus detection request may transmit the relay request to a different communication apparatus each time the relay request transfer section 0011 transmits the relay request. As a result, the multicasting of the apparatus detection request can be performed in a dispersed manner, whereby stability of the network is obtained.
The communication apparatuses having received the relay request at step S 1305 of FIG. 10 or at step S 1405 of FIG. 11 may each transmit, in consideration of processing load thereon, a relay rejection response from the relay rejection response transmission section (not shown) to the relay rejection response receiving section 0013 of the connection support server 001 . The relay rejection response receiving section 0013 , which has received the relay rejection response, retransmits the relay request to a communication apparatus which is stored in the communication path information storage section and which is different from the apparatus which is a transmission source of the relay rejection response. This makes it possible to, in the case where the apparatus which is requested to relay the apparatus detection request is unable to multicast the apparatus detection request due to a load imposed thereon, request a different apparatus, on which a processing load is not imposed, to relay the apparatus detection request. This prevents the apparatus from becoming incapable of performing processing.
Used as a message of an apparatus detection request may be an M-SEARCH request stipulated by UPnP, or may be a message stipulated by a different protocol.
The transmission manner of the apparatus detection request is not limited to multicasting. The transmission manner may be broadcasting or any other manner of data transmission.
The configuration described in the present embodiment is merely an example, and the present embodiment is not limited thereto.
For example, in the case where the connection support server 001 is connected to the private network 02 , the communication apparatus 302 can be detected from the communication apparatus 101 , and also the communication apparatus 102 or 302 can be detected from the communication apparatus 202 , by performing the same processing as described above.
Further, in the case where the connection support server 001 is connected to the private network 01 , an apparatus on the private network 02 or 03 can be detected from an apparatus on the private network 01 ; an apparatus on the private network 01 or 03 can be detected from an apparatus on the private network 02 ; and an apparatus on the private network 01 or 02 can be detected from an apparatus on the private network 03 .
It is assumed in the present embodiment that all the communication apparatuses each have an established communication path with the connection support server 001 . However, the present embodiment is not limited thereto. As long as there is, on a private network, at least one communication apparatus which has an established communication path with the connection support server 001 , even a communication apparatus which does not have an established communication path with the connection support server 001 can be detected by causing the at least one communication apparatus having the established communication path to perform the relaying in accordance with the processing sequence described in the present embodiment.
Third Embodiment
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 12 shows an exemplary configuration of an entire system according to the third embodiment of the present invention.
As shown in FIG. 12 , the global network 00 and the private network 01 are connected via the router 100 . The router 100 has the global IP address [IPW 100 ] as a WAN address and the private IP address [IPL 100 ] as a LAN address.
Also, the private network 01 and the private network 02 are connected via the router 200 . The router 200 has the private IP address [IPW 200 ] as a WAN address and the private IP address [IPL 200 ] as a LAN address.
Further, the private network 01 and the private network 03 are connected via the router 300 . The router 300 has the private IP address [IPW 300 ] as a WAN address and the private IP address [IPL 300 ] as a LAN address.
The communication apparatus 201 having the private IP address [IPL 201 ] and the communication apparatus 202 having the private IP address [IPL 202 ] are connected to the private network 02 .
The communication apparatus 301 having the private IP address [IPL 301 ] and the communication apparatus 302 having the private IP address [IPL 302 ] are connected to the private network 03 .
The connection support server 001 having the private IP address [IPL 001 ] is also connected to the private network 01 . The connection support server 001 has established communication paths through which the connection support server 001 can interactively communicate with all the communication apparatuses connected to the private networks 02 and 03 .
Block diagrams showing the configurations of the connection support server 001 and the communication apparatuses 201 , 202 , 301 and 302 are the same as those described in the first and second embodiments.
Described below in the present embodiment is an apparatus detection process which is performed in the case where the connection support server 001 is connected to the private network 01 .
Described first with reference to FIG. 13 is a process in which the communication apparatus 202 on the private network 02 detects the communication apparatus 302 on the private network 03 .
As shown in FIG. 13 , the apparatus detection request transmission section 2021 of the communication apparatus 202 multicasts via the communication section 2025 , on the private network 02 to which the communication apparatus 202 is connected, an apparatus detection request which designates the communication apparatus 302 as a search target (step S 1601 ). Here, since the communication apparatus 302 is not present on the private network 02 and the router 200 does not transfer the apparatus detection request to the private network 01 , a reception time-out occurs in the apparatus detection response receiving section 2022 for an apparatus detection response to be received from the communication apparatus 302 (step S 1602 ). Thus, the apparatus detection fails (step S 1603 ).
When the apparatus detection fails on the network of the communication apparatus 202 , the relay request transmission section 2023 of the communication apparatus 202 transmits, to the relay request transfer section 0011 of the connection support server 001 via the communication section 2025 , a request to relay the apparatus detection request (step S 1604 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus present on a different network (private network 02 ), the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the private network 02 (here, the private network 01 and the private network 03 ) (in this case, only the communication apparatus 301 is selected since there is no communication apparatus present on the private network 01 ), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 1605 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 3014 of the communication apparatus 301 extracts the search target (communication apparatus 302 ) from the relay request for the apparatus detection request (step S 1606 ), and multicasts, on the private network 03 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 3011 via the communication section 3015 (step S 1607 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 3021 of the communication apparatus 302 determines that the communication apparatus 302 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 3022 to the relay request processing section 3014 of the communication apparatus 301 via the communication section 3023 (step S 1608 ).
Upon receiving the apparatus detection response, the relay request processing section 3014 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 1609 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 2022 of the communication apparatus 202 (step S 1610 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 2022 of the communication apparatus 202 , the apparatus detection succeeds in detecting the communication apparatus 302 on the different private network (step S 1611 ).
Here, at step S 1601 , at the same time as the communication apparatus 202 multicasts, on the network thereof, the apparatus detection request from the apparatus detection request transmission section 2021 , the communication apparatus 202 may transmit, from the relay request transmission section 2023 to the relay request transfer section 0011 of the connection support server 001 , the relay request for the apparatus detection request. Accordingly, when an apparatus to detect is not present on the network of the communication apparatus 202 , the apparatus detection can be performed on a different network at the same time as the communication apparatus 202 waits for a response to be received. This allows a time, which is consumed until the apparatus is detected, to be reduced.
Used as a message of an apparatus detection request may be an M-SEARCH request stipulated by UPnP, or may be a message stipulated by a different protocol.
The transmission manner of the apparatus detection request is not limited to multicasting. The transmission manner may be broadcasting or any other manner of data transmission.
The configuration described in the present embodiment is merely an example, and the present embodiment is not limited thereto.
For example, in the case where the connection support server 001 is connected to the private network 02 , an apparatus on the private network 03 can be detected from an apparatus on the private network 02 by performing the same processing as described above. Also, an apparatus on the private network 02 can be detected from an apparatus on the private network 03 .
The same is true in the case where the connection support server is connected to the private network 03 .
It is assumed in the present embodiment that all the communication apparatuses each have an established communication path with the connection support server 001 . However, the present embodiment is not limited thereto. As long as there is, on a private network, at least one communication apparatus which has an established communication path with the connection support server 001 , even a communication apparatus which does not have an established communication path with the connection support server 001 can be detected by causing the at least one communication apparatus having the established communication path to perform the relaying in accordance with the processing sequence described in the present embodiment.
Fourth Embodiment
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 14 shows an exemplary configuration of an entire system according to the fourth embodiment of the present invention. As shown in FIG. 14 , the global network 00 and the private network 01 are connected via the router 100 . The router 100 has the global IP address [IPW 100 ] as a WAN address and the private IP address [IPL 100 ] as a LAN address.
Also, the private network 01 and the private network 02 are connected via the router 200 . The router 200 has the private IP address [IPW 200 ] as a WAN address and the private IP address [IPL 200 ] as a LAN address.
Further, the private network 01 and the private network 03 are connected via the router 300 . The router 300 has the private IP address [IPW 300 ] as a WAN address and the private IP address [IPL 300 ] as a LAN address.
A communication apparatus 401 having a global IP address [IPW 401 ] is connected to the global network 00 .
The communication apparatus 201 having the private IP address [IPL 201 ] and the communication apparatus 202 having the private IP address [IPL 202 ] are connected to the private network 02 .
The communication apparatus 301 having the private IP address [IPL 301 ] and the communication apparatus 302 having the private IP address [IPL 302 ] are connected to the private network 03 .
The connection support server 001 having the private IP address [IPL 001 ] is also connected to the private network 01 . The connection support server 001 has established communication paths through which the connection support server 001 can interactively communicate with all the communication apparatuses connected to the global network 00 , the private network 02 and the private network 03 .
Block diagrams showing the configurations of the connection support server 001 and the communication apparatuses 201 , 202 , 301 and 302 are the same as those described in the first and second embodiments.
FIG. 15 is a block diagram showing an exemplary configuration of the communication apparatus 401 according to the fourth embodiment of the present invention. As shown in FIG. 15 the communication apparatus 401 comprises: an apparatus detection request transmission section 4011 for multicasting, on a network thereof, an apparatus detection request for an apparatus which is desired to establish a communication with the communication apparatus 401 ; an apparatus detection response receiving section 4012 for receiving an apparatus detection response; a relay request transmission section 4013 for transmitting, to the connection support server, a request to relay the apparatus detection request; a relay request processing section 4014 for, when receiving from the connection support server 001 a request to relay an apparatus detection request, multicasting the apparatus detection request on the network of the communication apparatus 401 ; and a communication section 4015 for performing all the communications. The communication apparatus 401 is, for example, a mobile terminal having communication functions such as a mobile phone or PDA which is for operating another apparatus.
Since the communication apparatus 401 having the global IP address is unable to perform a request transmission by multicasting on the global network, the communication apparatus 401 may not necessarily have the apparatus detection request transmission section 4011 and the relay request processing section 4014 .
Described below in the present embodiment is an apparatus detection process which is performed in the case where the connection support server 001 is connected to the private network 01 .
Described first with reference to FIG. 16 is a process in which the communication apparatus 401 on the global network 00 detects the communication apparatus 302 on the private network 03 .
Since the network to which the communication apparatus 401 is connected is a global network, the communication apparatus 401 does not multicast an apparatus detection request, and the relay request transmission section 4013 of the communication apparatus 401 transmits, to the relay request transfer section 0011 of the connection support server 001 via the communication section 4015 , a relay request for an apparatus detection request (step S 1901 ).
When the relay request transfer section 0011 receives the relay request from the communication apparatus present on a different network (global network 00 ), the relay request transfer section 0011 selects, from the information stored in the communication path information storage section 0014 , an arbitrary apparatus of each of all the networks other than the global network 00 (here, the private networks 01 , 02 and 03 ) (in this case, the communication apparatuses 201 and 301 are selected since there is no communication apparatus on the private network 01 ), with which arbitrary apparatus a connection is to be established. Then, the relay request transfer section 0011 transmits, to the arbitrary apparatus via the communication section 0015 , the relay request for the apparatus detection request (step S 1902 ).
Upon receiving the relay request from the connection support server 001 , the relay request processing section 2024 of the communication apparatus 202 extracts the search target (communication apparatus 302 ) from the relay request for the apparatus detection request (step S 1903 ), and multicasts, on the private network 02 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 2021 via the communication section 2025 (step S 1904 ).
Since the communication apparatus 201 having received the apparatus detection request is not designated as the search target, the apparatus detection request receiving section 2011 of the communication apparatus 201 does not transmit an apparatus detection response.
Upon receiving the relay request from the connection support server 001 , the relay request processing section 3014 of the communication apparatus 301 extracts the search target (communication apparatus 302 ) from the relay request for the apparatus detection request (step S 1905 ), and multicasts, on the private network 03 , the apparatus detection request containing the extracted information, from the apparatus detection request transmission section 3011 via the communication section 3015 (step S 1906 ).
Upon receiving the apparatus detection request, the apparatus detection request receiving section 3021 of the communication apparatus 302 determines that the communication apparatus 302 is designated as the search target, and then transmits an apparatus detection response from the apparatus detection response transmission section 3022 to the relay request processing section 3014 of the communication apparatus 301 via the communication section 3023 (step S 1907 ).
Upon receiving the apparatus detection response, the relay request processing section 3014 transmits the response to the apparatus detection response transfer section 0012 of the connection support server 001 (step S 1908 ), and then the apparatus detection response transfer section 0012 transfers the apparatus detection response to the apparatus detection response receiving section 4012 of the communication apparatus 401 (step S 1909 ).
By receiving the apparatus detection response at the apparatus detection response receiving section 4012 of the communication apparatus 401 , the apparatus detection succeeds in detecting the communication apparatus 302 on the different private network (step S 1910 ).
Used as a message of an apparatus detection request may be an M-SEARCH request stipulated by UPnP, or may be a message stipulated by a different protocol.
The transmission manner of the apparatus detection request is not limited to multicasting. The transmission manner may be broadcasting or any other manner of data transmission.
The configuration described in the present embodiment is merely an example, and the present embodiment is not limited thereto.
For example, in the case where the connection support server 001 is connected to the private network 02 , an apparatus on the private network 02 or 03 can be detected from an apparatus on the global network 00 by performing the same processing as described above. Also, an apparatus on the global network 00 can be detected from an apparatus on the private network 02 or 03 .
The same is true in the case where the connection support server is connected to the private network 03 .
Further, in the present embodiment, the communication apparatus 401 on the global network 00 has a global IP address and is directly connected to the global network 00 . However, even in the case where the communication apparatus 401 is connected to a relay device having a global IP address such as a router and has a private IP address, the apparatus detection can be performed in the same manner.
It is assumed in the present embodiment that all the communication apparatuses each have an established communication path with the connection support server 001 . However, the present embodiment is not limited thereto. By causing a communication apparatus having an established communication path with the connection support server 001 to perform the relaying in accordance with the processing sequence described in the present embodiment, even a communication apparatus, which is connected to a same network as that of the communication apparatus and which does not have an established communication path with the connection support server 001 , can be detected.
INDUSTRIAL APPLICABILITY
The communication apparatus of the present invention is useful for, e.g., detecting an apparatus present on a different network in, e.g., a router multistage network comprising a plurality of routers. | A low cost communication apparatus enables detection of an apparatus present on a different network in a router multistage network having a plurality of routers. When a communication apparatus cannot detect, on a network thereof, a desired apparatus, the communication apparatus requests a connection support server securing communication paths with all the apparatuses on a home network, to relay an apparatus detection request. The connection support server transfers the request to relay the apparatus detection request, to an arbitrary apparatus belonging to a different network from the network to which the communication apparatus belongs, and the arbitrary apparatus, by proxy, performs an apparatus detection, and transfers information about a detected apparatus to the connection support server. By obtaining the information from the connection support server, the communication apparatus detects the apparatus on the different network. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to liquid waste distribution systems and in particular to a surface application system employing a centrifugal pump, a sludge gun and a vacuum/pressure distribution tank. The liquid treatment materials may be loaded via a vacuum action and are distributed via the pressurizing of the tank as the centrifugal pump pumps the materials to the sludge gun.
Liquid waste distribution systems have heretofore been employed for applying liquid-manure or the like in various surface and sub-surface application systems. Typically in such systems, the liquid matter is pumped into a distribution tank from a holding tank, nurse truck or lagoon and then conveyed to the field and surface applied via gravity flow or a pumped operation, most typically employing an impeller pump. Alternatively, subsurface application has also been achieved via equipment such as the present Assignee's Ag-Gator®2004 and 3004; Terra-Gator®2505; and Terra-Truck®1604 systems, among others.
For more information with respect to systems of the former type, however, attention is directed to U.S. Pat. Nos. 2,818,682; 3,339,846; 3,401,890; 3,490,695; 3,670,963; 3,717,285; and 4,186,885. These references generally contemplate the use of a hydraulic pump (typically of an impeller type) or the mixing of the liquid treatment materials at a spreader or nozzle at which a pressurized medium such as water or air is applied and by which the treatment materials are conveyed. The motive distribution power for the applied materials is thus obtained via the hydraulic pump or the carrier air or water stream with which the treatment materials are mixed.
The present invention, on the other hand, contemplates, in part, a vacuum/pressure system such as employed in the above referenced 2004, 3004, 2505 and 1604 distribution systems. In particular, the present system contemplates the use of a distribution tank that is loaded by operating a vacuum/pressure air pump in its vacuum mode so as to draw the liquid treatment materials from a storage reservoir and which distributes the liquid waste in close proximity to the vehicle by operating the vacuum/pressure pump only in its pressure mode, or for long distance surface distribution by operating the vacuum/pressure pump so as to super-charge or pressurize the distribution tank while pumping the materials from the tank via a submerged centrifugal pump and a tank mounted directional sludge gun. In this fashion, pump cavitation and consequential pump damage are avoided, while high flow rates and spread ranges of up to 150 feet are achieved for liquid treatment materials of up to 18% solids. Thus, it is possible to dispense the liquid in a relatively clog-free fashion at high flow rates and over large surface areas. Such an assembly is especially advantageous in that operating costs, such as gas consumption, are reduced and coverage can be achieved to otherwise inaccessible areas without having to physically drive thereover.
The present invention, therefore, contemplates a self-propelled chassis mounted distribution tank having an associated vacuum/pressure pump for loading liquid waste materials in a vacuum mode and evacuating the tank by operating the pump in a pressure mode. An associated "sludge gun" and submerged centrifugal pump are coupled to the distribution tank for controllably directing the release of the liquid waste at a desired higher pressure, in a desired stream type and in a highly directional fashion. These various objects, advantages and distinctions of the present invention, as well as various others will, however, become more apparent upon a reading of the following description with respect to the following drawings. It is to be appreciated though that while the present invention is described with respect to its presently preferred embodiment, various modifications or changes may be made thereto by those of skill in the art without departing from the scope of the present invention.
SUMMARY OF THE INVENTION
Liquid waste distribution apparatus comprising a mobile distribution tank having an associated vacuum/pressure pump, submerged centrifugal pump and top-mounted sludge gun assembly, whereby the liquid waste is loaded via the operation of the vacuum/pressure air pump in a vacuum mode and the waste is distributed via the sludge gun and the operation of the vacuum/pressure air pump in a pressure mode at the same time that the centrifugal pump pumps the pressurized material to the sludge gun. The sludge gun is hydraulically controlled for three-dimensionally rotating the nozzle so as to direct the spray. Spray shape and particulate size limit are determined by the nozzle size and pump pressure and flow developed.
DESCRIPTION OF THE DRAWING
FIG. 1 shows a perspective view of the present distribution apparatus and the relative positioning of its primary elements.
FIG. 2 shows a flow diagram of the liquid waste treatment material through the present equipment.
FIG. 3 shows a detailed perspective view of the present sludge gun.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a perspective view is shown of the present liquid waste distribution system and which generally is comprised of a chassis-mounted holding tank 2 that is permanently or trailer-mounted to a tractor-like forward power plant 4. For the present embodiment, the tractor 4 is comprised of a diesel-driven assembly supporting an operator's cab 6 above an axle 8 and a pair of heavy equipment flotation tires 10 that are mounted thereto. Mounted, in turn, to the forward end of the tractor 4 is a dozer blade that is used for light clearing of obstructions such as downed trees and the like, such as in silviculture operations.
It is to be recognized though that while a trailer-mount system is presently depicted numerous other configurations are contemplated, depending upon farm operation size and attendant equipment demands. Some of such equipment configurations can be observed upon reference to the present Assignees product literature and modular line of farm support equipment compatible with the Ag-Gator® and Terra-Gator® power chassis.
In any case, a trailerable distribution tank 2 is contemplated and which in the present embodiment is also supported on its own pair of driven flotation tires 10. While the tank size may vary, the present embodiment contemplates a tank of typically a 2,200 gallon capacity. In operation, such a tank would be filled from a nurse tank, holding pond or similar storage facility whereat the liquid-solid waste treatment materials would be kept. For instance, for a dairy operation, animal manure is oftentimes washed from the milking stations into a larger underground holding tank and from which the liquid materials are pumped into the present distribution tank, before spraying onto the farm fields. Alternatively and by way of contrast, solid-waste spreaders may be employed for some farm operations, but for others the present invention contemplates a liquid waste distribution system.
Associated with the rear-most end of the distribution tank 2 is a sub-surface multi-shank injector assembly 12 that may be used in appropriate circumstances to inject the treatment materials at a desired depth in specially created furrows so as to thereby bury the liquid material to avoid odor or to reduce evaporative loss of the nutrient components, especially nitrogen. Most typically, such an assembly is used where the terrain and ground conditions permit the conveying of the tank 2 and subsurface incorporation assembly 12 directly over the area to be treated and wherein the motive power to discharge the liquid is provided by the pressurization of the air above the liquid in the tank. However, where terrain or soil conditions do not permit subsurface application, the present apparatus includes a high-pressure pump system and top-mounted sludge gun 14 for spraying the treatment materials long distances to otherwise inaccessible areas, such as in a forest, in a surface application fashion. Specifically, such application is achieved via a vacuum/pressure air pump that pressurizes the tank 2 in a supercharged fashion while a submerged centrifugal pump 18 pumps the materials out and through the sludge gun 14. An associated hydraulic drive assembly 20 powers the centrifugal pump 18, while a related hydraulic drive assembly (shown in FIG. 2) three-dimensionally controls the spray direction of the sludge gun 14. The tank 2, in turn, may be loaded in a variety of ways via the reload port 22 or the hydraulically actuated and controlled hatch 26. Hatch 24, on the other hand, is a pressure sealed manway.
As mentioned, the tank 2 may be filled via the hatch 26 or via the reload port 22. Depending upon the type of farm operation, one or the other of these mechanisms may be advantageously employed. Where an overhead pump station is available, the hatch 26 facilitates top filling. Otherwise, where the tank 2 is filled from a resevoir, lagoon or nurse truck, the tank is more readily filled via the reload port 22 and the simultaneous operation of the vacuum/pressure air pump 30 in a vacuum mode. For the present embodiment, the vacuum/pressure air pump 30 is comprised of a 192 CFM pressure/vacuum air pump and which has been found to adequately handle liquid waste having a solids content of up to on the order of 18%.
Referring next to FIG. 2, a generalized block diagram is shown of the present distribution system as it relates to its associated spray operation via the sludge gun 14. Generally and as mentioned, such operation requires the vacuum filling of the distribution tank 2 from a supply resevoir. Upon reaching the desired distribution site, the vacuum/pressure pump 30 is switched to its pressure mode of operation so as to pressurize the tank 2 via the conduit 31 coupled to the tank hatch 24. The submerged centrifugal pump 18 is driven via the hydraulic motor 20 and the mechanical shaft linkage (not shown) contained in conduit 32 so as to pump the materials from the tank 2 via conduit 34 at pressures up to 90 psi and spray them in a highly directional fashion at ranges of up to 150 feet while the tank 2 is pressurized by the air pump 30 in its pressure mode to approximately 10 psi. Thus, the present system is able to spread sludge into a forested arear from logging trails accesible to the vehicle.
Before continuing, it is to be noted that when used in conjunction with the subsurface distribution assembly 12 the vacuum/pressure pump 30 is operated alone to pressurize the air in the tank 2 to force the treatment materials to the injectors. For this type of soil application, the low pressure is sufficient to accommodate the distance over which the treatment materials must be conveyed. However, the pump 30 is not sufficient in and of itself to pressurize the tank to a pressure adequate enough to convey the materials the desired 100 or so feet. On the other hand, though, the pump 30 is of a sufficient size so as to super-charge the tank 2 to a pressure on the order of 10 PSI and thereby facilitate the removal of the treatment materials via the centrifugal pump 18 and which provides the necessary relatively high pressure. In particular, because the treatment materials are under pressure as they enter the centrifugal pump 18, they are easily removed by the pump 18 without pump cavitation and which would otherwise occur since the viscous waste materials by their inherent nature would otherwise resist flow into the centrifugal pump 18 (whether submerged or externally located). It is also to be noted that the centrifugal pump 18 is mounted slightly above the bottom of the tank 2 and which thereby permits a substantially complete pump down. As mentioned, too, the drive power to the pump 18 is supplied via the hydraulic supply lines (not shown) and the hydraulic motor that is connected to the drive shaft contained in casing 32, while the pumped materials are supplied to the sludge gun 14 via the conduit 34 and which is typically sized to be on the order of three inches in diameter.
The sludge gun 14 and pump assembly, in turn, is mounted to the tank 2's cover plate 36 so as to be removable as an integral assembly. The gun 14 is also rotatable over 240°, and the various controls for achieving such rotation and elevational changes will be discussed hereinafter with respect to FIG. 3. It is to be noted, too, that the sludge gun 14 that is employed in the present embodiment is of a type manufactured by Stang Corporation and which are often encountered in various fire fighting apparatus, mining and construction equipment. Therefore, the specific details relative to the internal operation and mechanisms of the sludge gun 14 will not be discussed in detail, but rather the reader is directed to the various related product literature of the Stang Corporation.
Referring next to FIG. 3, a detailed perspective view is shown of the tank 2's cover plate 36 and associated hydraulic drive assembly 20 and sludge gun 14, as well as its associated directional drive controls. From FIG. 3, it is to be noted that the sludge gun 14 is directionally operable either manually or automatically via the rotational hand screw 38, rotational hydraulic drive 40, elevational hand screw 42, and/or elevational hydraulic drive 44. If operated manually, the hand screws 38 and 42 are used to control internal screw drive assemblies (not shown) and which, in turn, direct the nozzle 46. Alternatively and more preferrably, such directional control is achieved via the hydraulic drive lines that are coupled to the hydraulic drive assemblies 40 and 44 and which are operative from the cab 6 by the operator. Thus, it is not necessary for the operator to leave the cab 6 during treatment application. Similarly, the hydraulic drive power is supplied to the submerged pump 18 via the cab-controlled hydraulic motor assembly 20 and which, as mentioned, is actuated, upon the tank 2 being properly pressurized.
From the foregoing, it should be apparent that the present invention offers an improved assembly whereby liquid treatment materials of relatively high solids content may more advantageously be surface applied. It should also be apparent that while the present invention has been described with respect to its preferred embodiment, various modifications or changes might be made thereto without departing from the spirit of the invention. It is, therefore, contemplated that the following claims will be interpreted to include all equivalent embodiments within the scope thereof. | A vacuum/pressure liquid waste application system for vacuum loading a distribution tank with liquid waste treatment materials and distributing the liquid matter via a pressurized tank and flow-forming and directing sludge gun. Clog-free directional surface application is thereby achieved over relatively rugged or inaccessible terrain. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetron which is applied to a microwave oven or the like, and more particularly, it relates to a magnetron which has a cathode provided with an improved end shield.
2. Description of the Prior Art
FIG. 1 is a typical diagram schematically showing the structure of a microwave oven, for example, to which a magnetron is applied. Referring to FIG. 1, a microwave oven 1000 has a magnetron 100, a driving power source 200 for driving the magnetron 100 and a waveguide 300. The entire microwave oven 1000 is covered with a microwave oven cover 400. Microwaves oscillated from the magnetron 100 are guided into an internal space 500 of the microwave oven 1000 through the waveguide 300. Food 700 placed on a pan 600 is heated and cooked by such microwaves.
FIG. 2A is a partially fragmented front elevational view showing the structure of a conventional magnetron which is disclosed in Japanese Patent Publication Gazette No. 45340/1986, for example. FIG. 2B is a partial sectional view taken along the line IIB--IIB in FIG. 2A. FIG. 2C is a partial sectional view taken along the line IIC--IIC in FIG. 2B. The structure of such a typical conventional magnetron is now described with reference to these figures.
Referring to FIGS. 2A to 2C, a magnetron 100 is provided with a cathode 3 in its central portion. The cathode 3 has a filament 5 (see FIG. 2c), which emits electrons. A plurality of panel-shaped vanes 2 of oxygen free copper or the like are radially arranged to encircle the cathode 3. The vanes 2 have base end portions which are fixed to the inner wall of an anode cylinder 1 of oxygen free copper, or integrally formed with the anode cylinder 1. Two inner strap rings 9, which are selected to be identical in diameter to each other, are provided on upper and lower ends (in FIGS. 2A and 2C) of the vanes 2. The inner strap rings 9 are arranged in positions separated by a l prescribed distance from the forward end portions of the vanes 2 (see FIG. 2c) with respect to the full length L of the vanes 2. Further, two outer strap rings 10, which are selected to have the same diameters, being larger than those of the inner strap rings 9, are provided on the upper and lower ends of the vanes 2. The inner and outer strap rings 9 and 10 are so fixed to the vanes 2 as to short-circuit every other vane 2. In other words, the upper one of the inner strap rings 9 and the lower one of the outer strap rings 10 are fixed to the same alternately-arranged vanes 2, while the upper one of the outer strap rings 10 and the lower one of the inner strap rings 9 are fixed to the remaining vanes 2 respectively. The respective adjacent vanes 2 and the inner wall of the anode cylinder 1 define spaces 14 (see FIG. 2b)partially opened toward the cathode 3, thereby to form cavity resonators. The oscillation frequency of the magnetron 100 is determined by the resonance frequency of such cavity resonators. In a central portion of the anode cylinder 1, a cylindrical space is axially defined by the forward end portions of the vanes 2. The cathode 3 is arranged in this space. The space 4 thus held between the cathode 3 and the vanes 2 at a prescribed distance is called an interaction space. A uniform direct-current magnetic field is applied to the interaction space 4 in parallel with the central axis of the cathode 3. To this end, permanent magnets 12 are arranged in the vicinity of upper and lower ends of the anode cylinder 1 respectively (see FIG. 2a). Direct-current or low-frequency high voltage is applied between the cathode 3 and the vanes 2.
In FIG. 2c, the cathode 3 is formed by the filament 5, which is helically prepared from tungsten containing thorium or the like, a top hat 7 supporting the upper end of the filament 5 and having a flange part 6 which is larger in outer diameter than the filament 5 in its upper portion and an end hat 8 supporting the lower end of the filament 5. The top hat 7 and the end hat 8 are formed of a metal having a high melting point, such as molybdenum. The top hat 7 and the end hat 8 are adapted to prevent axial deviation of electrons from the filament 5. Alternate ones of the vanes 2 are electrically connected with each other since the inner strap rings 9 and the outer strap rings 10 are alternately fixed to the upper and lower ends of the vanes 2, as hereinabove described. An antenna conductor 11 (see FIGS. 2a, 2c) is so provided that an end thereof is connected with one of the vanes 2.
In the aforementioned structure, high-frequency electric fields formed in the cavity resonators are concentrated to the forward end portions of the respective vanes 2, and partially leak into the interaction space 4. Since the inner and outer strap rings 9 and 10 couple alternate ones of the vanes 2, the respective adjacent vanes 2 are at reverse potentials in high frequency. An electron group emitted from the cathode 2 rotates about the cathode 3 in the interaction space 4, whereby interaction takes place between the electron group and the high-frequency electric fields, to cause oscillation of microwaves. The microwaves obtained by such oscillation are outwardly guided through the antenna conductor 11 which is connected with one of the vanes 2. Since conversion efficiency into microwave power is not 100%, the energy of the electron group is partially consumed as heat. Therefore, fins 13 (see FIG. 2a) are provided along the outer circumference of the anode cylinder 1 for radiating the heat. FIG. 2B, 2C shows only the internal structure of the anode cylinder 1, and fins 13 etc. are not shown in this figure.
International Standards are established by ITU (International Telecommunication Union) for the aforementioned magnetron, and the basic frequency of 2450 MHz is allocated to food heating apparatuses, medical appliances, parts of industrial instruments and the like. In such application, therefore, the magnetron 100 ideally oscillates only microwaves at the basic frequency of 2450 MHz (±50 MHz), whereas the same generates various higher harmonics in practice. Within such higher harmonics, particularly the fifth harmonic having a frequency of 12.25 GHz (±0.25 GHz), there is an overlap with a working frequency range of satellite broadcasting, which has been tested since around 1981 and more recently has been in use, creates serious problems. For example, while radio frequency allocation for SHF satellite broadcasting is varied with areas of nations, the frequency range thereof is set in a range of 11.7 to 12.75 GHz.
In the magnetron having the aforementioned structure, further, the filament 5 is abnormally heated by generation of cathode back bombardment, whereby the filament 5 may be fused in an extreme case.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a magnetron, which can suppress undesired higher harmonics, particularly the fifth harmonic, as well as cathode back bombardment.
The magnetron according to the present invention comprises an anode cylinder, vanes, an antenna conductor, strap ring means, a cathode and magnet means. A plurality of panel-shaped vanes are provided on the inner wall of the anode cylinder toward the center of the anode cylinder. The vanes, which are separated from each other at intervals, have edges provided on forward end portions thereof and first and second end surfaces along an axial direction of the anode cylinder. The antenna conductor is electrically connected with the first end surface, along the axial direction, of one of the vanes. The strap ring means electrically couples alternate ones of the vanes with each other. The cathode is provided in the anode cylinder to extend along the axial direction of the anode cylinder in relation separated from the edges of the forward end portions of the vanes. Thus, an interaction space is defined between the edges of the forward end portions of the vanes and the cathode. The cathode comprises a filament, a first end shield and a second end shield. The filament is provided to extend along the axial direction of the anode cylinder. The first end shield supports a first end, along the axial direction, of the filament and has a flange part which is larger in outer diameter than the filament. This flange part has an inner surface facing the interaction space. The second end shield supports a second end, along the axial direction, of the filament. The magnet means is adapted to provide a magnetic field in the interaction space along the axial direction of the anode cylinder. The magnetron generates microwaves of a prescribed basic frequency, while inevitably generating higher harmonics accompanying the basic frequency. The first end shield is so provided that the inner surface of the flange part thereof is located in a position closer to the interaction space by length within a range of 0.1 to 0.6 mm from the first ends of the vanes along the axial direction, thereby to suppress generation of the fifth harmonic.
In a magnetron according to another aspect of the present invention, the strap ring means has an inner diameter which is so selected that the ratio l/L exceeds a prescribed minimum value calculated to highly suppress generation of the fifth harmonic of the basic frequency. Symbol l represents the distance between the inner peripheral surface of the strap ring means and the edges of the forward end portions of the vanes, and L represents the length of the vanes.
According to a preferred embodiment of the present invention, the first end shield is so provided that the inner surface of the flange part is located in a position closer to the interaction space by length within a range of 0.2 to 0.4 mm from the first end surfaces of the vanes along the axial direction. The basic frequency may be selected within a range of 2400 to 2500 MHz.
According to the present invention, generation of undesired higher harmonics, particularly the fifth harmonic, can be efficiently suppressed without adding new structure to the conventional magnetron but by simply changing part of its structure, i.e., the position of the flange part of the first end shield, within a technically limited range. Further, generation of cathode back bombardment can be also suppressed.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a typical diagram schematically showing the structure of a conventional microwave oven, as an exemplary apparatus to which a magnetron is applied;
FIG. 2A is a partially fragmented front elevational view showing the structure of a conventional magnetron;
FIG. 2B is a partial sectional view taken along the line IIB--IIB in FIG. 2A;
FIG. 2C is a partial sectional view taken along the line IIC--IIC in FIG. 2B;
FIG. 3 is a partial sectional view showing a magnetron according to the present invention, in correspondence to FIG. 2C;
FIG. 4 is a characteristic diagram showing relation of a space (a) between the lower surface of a flange part of a top hat and upper ends of vanes to the level of fifth harmonic radiation in the present invention;
FIG. 5 is a characteristic diagram showing relation of the space (a) between the lower surface of the flange part of the top hat and the upper ends of the vanes to the maximum anode current which is capable of stable oscillation in the present invention;
FIG. 6 is a characteristic diagram showing relation of the space (a) between the lower surface of the flange part of the top hat and the upper ends of the vanes to the ratio of filament current in preheating to that in π-mode oscillation in the present invention; and
FIG. 7 is a characteristic diagram showing relation of the space (a) between the lower surface of the flange part of the top hat and the upper ends of the vanes, the inner diameter of an inner strap ring and the level of fifth harmonic radiation in the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The inventors have found that one of the causes for the aforementioned higher harmonics and cathode back bombardment may be the position of the cathode. In the structure of the conventional magnetron shown in FIG. 2C, the lower surface of the flange part 6 of the top hat 7 supporting the upper end of the cathode 3 is positioned above the upper ends of the vanes 2. For example, the space a between the lower surface of the flange part 6 and the upper ends of the vanes 2 is set at about 0.4 to 0.6 mm. In such conventional structure, a high-frequency electric field of the antenna conductor 11 exerts influence on the interaction space 4, to disturb electric field distribution in the interaction space 4. It is considered that smooth movement of the electrons is thus prevented, to cause higher harmonic noise and cathode back bombardment. The present invention is adapted to provide the lower surface of a flange part of a top hat supporting the upper end of a filament in a position lower than the upper ends of vanes by a prescribed distance, thereby to suppress generation of the fifth harmonic and cathode back bombardment.
For example, each of Japanese Patent Publication Gazette No. 32946/1985 and U.S. Pat. No. 4,223,246 discloses the structure of a magnetron in which the lower surface of a flange part of a top hat supporting the upper end of a filament is provided in a position lower than upper ends of vanes similarly to the present invention. However, such literature merely illustrates positional relation between the lower surface of the flange part of the top hat and the upper ends of the vanes, but makes no description of technical significance of such positional relation. This may be because it was not necessary to consider higher harmonics caused by a magnetron in patent applications for the aforementioned examples, which were filed in 1979 before starting of a test for satellite broadcasting. Thus, it is clear that no one has found that positional relation between the lower surface of a flange part of a top hat and the upper ends of vanes is related to the generation level of fifth harmonic noise. Further, it has been common knowledge for those skilled in the art to position the lower surface of the flange part of the top hat above the upper ends of the vanes as shown in FIG. 2C, in order to attain stable oscillation in a π-mode. The present invention has attained its object of suppressing generation of the fifth harmonic with no regard to such conventional technical knowledge, and is not anticipated by the aforementioned two examples. Although the lower surface of a flange part of a top hat is provided in a position lower than the upper ends of vanes according to the present invention, stable oscillation in a π-mode is not prevented by such structure, as clarified in the following description.
FIG. 3 is a partially enlarged sectional view illustrating an embodiment of the present invention in correspondence to FIG. 2C showing the conventional magnetron. Referring to FIG. 3, this embodiment is identical in structure to the conventional magnetron shown in FIG. 2C, except for positional relation between a flange part 6 of a top hat 7 and vanes 2. A cathode 3 is provided in a lower portion, and the lower surface of the flange part 6 of the top hat 7 is provided in a position lower than the upper ends of the vanes 2.
It is assumed that respective dimensions (a-n) shown in FIG. 3 are set at the following values, for example:
Space a between the lower surface of the flange part 6 at the top hat 7 and the upper ends of the vanes 2: dimension is variable as shown in FIGS. 4 to 7.
Vertical length b of the vanes 2: dimension is variable as shown in FIGS. 4 to 7.
Inner diameter c of anode cylinder 1: 35.0 mm.
Space d between each pair of opposite vanes 2: 9.0 mm.
Outer diameter e of filament 5: 4.0 mm.
Outer diameter f of flange part 6 of top hat 7: 7.2 mm.
Thickness g of flange part 6: 1.0 mm.
Outer diameter h of end hat 8: 7.2 mm.
Vertical length i from upper surface to lower surface of end hat 8: 2.5 mm.
Vertical distance j between lower surface of flange part 6 of top hat 7 and upper surface of end hat 8: 9.8 mm.
Distance k between axis of anode cylinder 1, i.e., axis of cathode 3 and position of antenna conductor 11 mounted on one vane 2: 12.9 mm.
Length L of vane 2: 13.0 mm.
Distance l between inner peripheral surface of inner strap ring 9 and forward end portion of vane 2: 3.25 mm.
Distance n between vane 2 and bent portion of antenna conductor 11: 2.0 mm.
Angle m of bending of bent portion of antenna conductor 11: 145°.
FIGS. 4 to 7 show results of measurement obtained with the respective dimensions set as above. Characteristics of the inventive magnetron are now described with reference to these characteristic diagrams.
FIG. 4 is a characteristic diagram prepared on the basis of experimental data for showing how the fifth harmonic radiation level is varied with the space a between the lower surface of the flange part 6 of the top hat 7 and the upper ends of the vanes 2. Referring to FIG. 4, the vertical length b of the vanes 2 is varied with curves A, B and C as follows:
A:b=9.6 mm
B:b=9.2 mm
C:b=8.8 mm
The space a between the lower surface of the flange part 6 of the top hat 7 and the upper ends of the vanes 2 is at a positive value when the lower surface of the flange part 6 is positioned above the upper ends of the vanes 2, while the same is at a negative value when the lower surface of the flange part 6 is positioned under the upper ends of the vanes 2, in each characteristic diagram. Further, the magnetron is supplied with voltage of 4 kV and anode current of 300 mA. FIG. 4 shows the fifth harmonic radiation level as a relative value based on the radiation level in case of a=0.4 mm.
When the vertical position of the top hat 7 is lowered, substantially no change is caused in the relative value of the fifth harmonic radiation level until the value a reaches zero, i.e., until the lower surface of the flange part 6 of the top hat 7 is flush with the upper ends of the vanes 2, as seen from FIG. 4. Reduction of the relative value of the fifth harmonic radiation level starts when the lower surface of the flange part 6 is lower by 0.1 mm the upper ends of the vanes 2. It is understood that, when the lower surface of the flange part 6 is lower than the upper ends of the vanes 2 by at least 0.2 mm, the relative value of the fifth harmonic radiation level substantially reaches a constant value which is lower than that in the case of a=-0.1 mm.
In order to suppress generation of the fifth harmonic, therefore, it is preferable to provide the lower surface of the flange part 6 of the top hat 7 in a position lower than the upper ends of the vanes 2 by at least 0.1 mm, and more preferably, by at least 0.2 mm.
FIG. 5 is a characteristic diagram prepared on the basis of experimental data, for illustrating how the critical point of a moding, in which a regular high-frequency electric field of a π-mode in the magnetron is so disturbed that the π-mode cannot be correctly maintained, is varied with the space a between the lower surface of the flange part 6 of the top hat 7 and the upper ends of the vanes 2, in maximum anode current capable of stable oscillation. Similarly to FIG. 5, the vanes are 9.6 mm, 9.2 mm and 8.8 mm in vertical length b in curves A, B and C respectively.
When the vertical position of the top hat 7 is lowered, the critical point of the maximum anode current which is capable of stable oscillation is substantially at a constant value until the lower surface of the flange part 6 of the top hat 7 reaches a position lower by 0.4 mm than the upper ends of the vanes 2, as seen from FIG. 5. It is understood that, when the lower surface of the flange part 6 is in a position lower than the upper ends of the vanes 2 by at least 0.4 mm, the anode current value is reduced with downward movement of the said lower surface. There is the possibility that stable oscillation cannot be maintained in a microwave oven etc. to which the magnetron is applied, when the anode current value serving as the critical point is not more than 700 mA.
In order to attain stable oscillation, therefore, the limit for downwardly moving the lower surface of the flange part 6 of the top hat 7 is a position lower by 0.6 mm than the upper ends of the vanes 2. If the lower surface of the flange part 6 is further downwardly moved, stable oscillation cannot be suitably attained. Thus, it is desirable to provide the lower surface of the flange part 6 in a position lower by 0.4 mm than the upper ends of the vanes 2, in order to attain good stable oscillation.
FIG. 6 is a characteristic diagram prepared on the basis of experimental data, for illustrating the degree of generation of anode back bombardment caused when the space a between the lower surface of the flange part 6 of the top hat 7 and the upper ends of the vanes 2 is changed, in the ratio (I 1 /I 0 ) of filament current (I 1 ) in π-mode oscillation to filament current I 0 ) in preheating. The vertical length b of the vanes 2 is 8.8 mm in this case.
As seen from FIG. 6, the ratio (I 1 /I 0 ) is increased as the vertical position of the top hat 7 is lowered. It is understood that the ratio (I 1 /I 0 ) reaches a substantially constant value when the lower surface of the flange part 6 of the top hat 7 is provided in a position lower by at least 0.1 mm than the upper ends of the vanes 2.
When cathode back bombardment is caused in oscillation, the temperature of the filament 5 is raised to increase filament resistance, whereby the filament current (I 1 ) is reduced. Thus, it is considered that generation of cathode back bombardment is reduced as the ratio (I 1 /I 0 ) is increased. In other words, it is understood that generation of cathode back bombardment is reduced as the vertical position of the top hat 7 is lowered.
In order to suppress generation of cathode back bombardment, therefore, it is preferable to provide the lower surface of the flange part 6 of the top hat 7 in a position lower than the upper ends of the vanes 2 by at least 0.1 mm, and more preferably, at least 0.2 mm.
It is understood from the characteristic diagrams shown in FIGS. 4 to 6 that the space a between the lower surface of the flange part 6 of the top hat 7 and the upper ends of the vanes 2 is preferably within a range of -0.6 mm≦a≦-0.1 mm, and most preferably within a range of -0.4 mm≦a≦0.2 mm. It is considered that, when the value a is set in such a range, the high-frequency electric field of the antenna conductor 11 hardly enters the interaction space and disturbance in electric field distribution within the interaction space is suppressed while electrons can smoothly move in the interaction space, whereby generation of higher harmonics and cathode back bombardment can be suppressed.
FIG. 7 is a characteristic diagram prepared on the basis of experimental data for showing the level of fifth harmonic radiation varied with positions of inner strap rings 9 and outer strap rings 10 in the magnetron shown in FIG. 3. Curves shown in FIG. 7 represent relative values of the fifth harmonic radiation level obtained when values of l/L×100 are 13, 18, 21, 25, 28, 32 and 35 respectively. Such relative values of the fifth harmonic radiation level are on the basis of a value obtained when l/L×100 =13% and a=0.4 mm. The vertical length b of the vanes 2 is 8.8 mm in this case. Symbol L indicates the full length of the vanes 2 shown in FIG. 3, and symbol l indicates the distance between the forward end portions of the vanes 2 and the inner peripheral surface, i.e., a surface facing the cathode 3, of each inner strap ring 9. The space between the inner and outer strap rings 9 and 10 is regularly at a constant value of 0.8 mm.
It is understood from FIG. 7 that the fifth harmonic radiation level is extremely reduced as the position of each inner strap ring 9 is separated from the forward end portions of the vanes 2. Particularly when the position of the inner strap ring 9 is within a range of at least 18% and at most 35% with respect to the full length L of the vanes 2 from the forward end portions of the vanes 2, generation of the fifth harmonic can be extremely suppressed. Preferably the range is at least 21% and at most 32%.
U.S. Pat. No. 4,720,659 in the name of the inventors discloses the technique of separating the strap rings from the forward end portions of the vanes by constant distances in order to suppress generation of the fifth harmonic radiation level. When the lower surface of the flange part 6 of the top hat 7 is provided in a position lower than the upper ends of the vanes 2 in addition to the aforementioned positional setting of the strap rings, it is possible to further suppress generation of the fifth harmonic radiation level, as shown in FIG. 7.
The relative values of the fifth harmonic radiation level shown in FIG. 4 are different from those shown in FIG. 7, due to difference in reference values of the fifth harmonic radiation level. FIG. 4 is based on the fifth harmonic radiation level obtained when l/L×100=13% and a=0.4 mm, while FIG. 7 is based on the fifth harmonic radiation level obtained when l/L×100=13% and a=0.4 mm.
Although the above description has been made with reference to a magnetron which has the basic frequency of 2450 MHz, the present invention is not restricted to this, but is also applicable to a magnetron whose basic frequency is selected at any value in a frequency range of 2400 to 2500 MHz, for example, and that having a basic frequency out of such a range.
FIG. 2A merely shows an exemplary conventional magnetron, and FIG. 3 shows exemplary structure of a principal part in case of applying the present invention in the entire structure of the magnetron shown in FIG. 2A. It is also possible to apply the present invention to another magnetron having slight modification.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | In an interaction space (4) defined between a cathode (3) and forward end portions of vanes (2), a permanent magnet (12) applies a uniform direct-current magnetic field along an axial direction of the cathode (3). Direct-current or low-frequency high voltage is applied between the cathode (3) and the respective vanes (2). Spaces (14) enclosed by respective pairs of adjacent vanes (2) and the inner wall of an anode cylinder (1) define cavity resonators. High-frequency electric fields formed in the cavity resonators are concentrated to the forward end portions of the vanes (2), and partially leak into the interaction space (4). Under such conditions, an electron group emitted from the cathode (3) rotates about the cathode (3) in the interaction space (4), thereby interaction takes place between the electron group and the high-frequency electric fields, to oscillate microwaves. The inner surface of a flange part (6) of a top hat (7) supporting one end of a filament (5) of the cathode (3) is located in a position closer to the interaction spaces (4) by length within a range of 0.1 to 0.6 mm from first end surfaces of the vanes (2) along the axial direction, thereby to suppress undesired fifth harmonic generated with the microwaves of a basic frequency at this time. | 7 |
BACKGROUND OF THE INVENTION
The preparation of alkylsaccharides via the acid catalyzed reaction of an alcohol and a reducing sugar containing either 5 or 6 carbon atoms, is well known. Examples of patents disclosing such processes include U.S. Pat. No. 3,598,865, Lew, patented Aug. 10, 1971; U.S. Pat. No. 3,219,656, Boettner, patented Nov. 23, 1965; U.S. Pat. No. 3,346,558, Roth, patented Oct. 10, 1967; U.S. Pat. No. 3,547,828, Mansfield et al, patented Dec. 15, 1970; U.S. Pat. No. 3,707,535, Lew, patented Dec. 16, 1972; U.S. Pat. No. 3,772,269, Lew, patented Nov. 13, 1973; U.S. Pat. No. 3,839,318, Mansfield, patented Oct. 1, 1974; and U.S. Pat. No. 4,223,129, Roth et al, patented Sept. 16, 1980, all of said patents being incorporated herein by reference. In all of these processes, colored materials are formed.
Various approaches to cleaning up the alkylsaccharides have been disclosed including extraction of the desired material. U.S. Pat. No. 2,258,168, White, patented Oct. 7, 1941; U.S. Pat. No. 2,715,121, Glenn et al, patented Aug. 9, 1965; and U.S. Pat. No. 3,450,690, Gibbons et al, patented June 17, 1969, disclose methods for removal of color producing bodies by extracting the desired product. U.S. Pat. No. 3,839,318, Mansfield, patented Oct. 1, 1974, discloses a process for bleaching the colored materials using perborate. All of the above patents are incorporated herein by reference.
SUMMARY OF THE INVENTION
This invention relates to the process of removing colored materials from alkylsaccharides by extracting the colored materials with a polar solvent under essentially anhydrous conditions.
DETAILED DESCRIPTION OF THE INVENTION
Polar Solvent
Polar solvents useful in the extraction process should have a boiling point between about 30° C. and about 200° C., preferably between about 45° C. and about 150° C., and have a dipole moment of greater than about 1.0, preferably greater than about 1.2 and less than about 4, preferably less than about 3, more preferably less than about 2.5. Suitable solvents include tetrahydrofuran, acetone, di-N-propyl ether, dioxane, bis-2-methoxyethyl ether, dimethyl sulfoxide, dimethyl sulfone, di-N-propyl sulfone, dibutyl oxide, bis-2-methoxyethyl ether (Diglyme), nitrobenzene, acetonitrile, formamide, dimethyl formamide, methyl ethyl ketone, diethyl ketone, butyl aldehyde, ethyl acetate, propyl acetate, ethyl cellulose, butyl cellulose, chloroform, methylene chloride, freon, tetrachloro ethylene, and mixtures thereof. The preferred solvents are acetone, ethyl acetate, methyl ethyl ketone, diethyl ketone, and mixtures thereof. Mixtures of the above compounds with nonpolar solvents are also suitable and even desirable.
It is important that the solvent be anhydrous, i.e., it should contain less than about 2%, most preferably less than about 0.5% water. Also, it preferably should be nontoxic and be readily distilled to remove it from the colored materials.
The Alkylsaccharide
The alkylsaccharide is any compound in which the alkyl group is attached through the number one carbon atom of a 5- or 6-member reducing saccharide to said saccharide, or a polysaccharide chain. The compounds are formed by the reaction between an alcohol and a 5- or 6-membered reducing saccharide or source thereof. The alcohol can be either aliphatic or aromatic, or mixed aliphatic and aromatic, containing from 1 to about 32 carbon atoms, preferably from about 8 to about 24, most preferably from about 12 to about 18, and the saccharide portion of the molecule can contain from about 1 to about 50 saccharide monomers on the average. Such compounds are formed in the presence of acid catalysts, usually with the application of heat. Such compounds and the processes for making such compounds are well known and described in the patents incorporated hereinbefore.
Preferred compounds are those having a hydrophobic group containing from about 8 to about 20 carbon atoms, preferably from about 10 to about 16 carbon atoms, most preferably from 12 to 14 carbon atoms, and a polysaccharide hydrophilic group containing from about 1.5 to about 10, preferably from 1.5 to 4, most preferably from 1.6 to 2.7 saccharide units (e.g., galactoside, glucoside, and/or fructoside, units). Mixtures of saccharide moieties can be present in the alkyl polysaccharide surfactants. For a particular alkylpolysaccharide molecule the number of saccharide units (X) can only assume integral values. In any physical sample of alkylpolysaccharide surfactants there will, in general, be molecules having different X values. The physical sample can be characterized by the average value of X and this average value can assume non-integral values. In this specification the values of X are to be understood to be average values.
Optionally and less desirably there can be a polyalkoxide chain joining the hydrophobic moiety (R) and the polysaccharide-chain. The preferred alkoxide moiety is ethoxide.
Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched, containing from about 8 to about 20, preferably from about 10 to about 16 carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to 3 hydroxy groups and/or the polyalkoxide chain can contain up to about 30, preferably less than 10, most preferably 0, alkoxide moieties.
Suitable alkyl polysaccharides are decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, di-, tri-, tetra-, penta-, and hexaglucosides, galactosides, lactosides, fructosides, and mixtures thereof.
The alkylmonosaccharides are relatively less soluble in water than the higher alkylpolysaccharides. When used in mixtures with alkylpolysaccharides, the alkylmonosaccharides are solubilized to some extent. The use of alkylmonosaccharides in mixtures with alkylpolysaccharides is preferred. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.
The preferred alkyl polysaccharides are alkyl polyglycosides having the formula
R.sup.2 O(C.sub.n H.sub.2n O).sub.t (Z).sub.x
wherein Z is derived from glucose, R 2 is a hydrophobic group selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl groups contain from about 10 to about 18, preferably from 12 to 14 carbon atoms; n is 2 or 3, preferably 2; t is from 0 to about 10, preferably 0; and x is from 1.5 to about 8, preferably from 1.5 to 4, most preferably from 1.6 to 2.7. To prepare these compounds a long chain alcohol (R 2 OH) can be reacted with glucose, or a compound hydrolyzable to glucose, in the presence of an acid catalyst to form the desired glycoside. Alternatively the alkylpolyglycosides can be prepared by a two step procedure in which a short chain alcohol (C 1-6 ) is reacted with glucose or a polyglycoside (x=2 to 4) to yield a short chain alkyl glycoside (x=1 to 4) which can in turn be reacted with a longer chain alcohol (R 2 OH) to displace the short chain alcohol and obtain the desired alkylpolyglycoside. If this two step procedure is used, the short chain alkylglycoside content of the final alkylpolyglycoside material should be less than 50%, preferably less than 10%, more preferably less than 5%, most preferably 0% of the alkylpolyglycoside.
The amount of unreacted alcohol (the free fatty alcohol content) in the preferred alkylpolysaccharide surfactant is preferably less than about 2%, more preferably less than about 0.5% by weight of the total of the alkyl polysaccharide plus unreacted alcohol. The amount of alkylmonosaccharide is about 20% to about 70%, preferably 30% to 60%, most preferably 30% to 50% by weight of the total of the alkylpolysaccharide. For some uses it is desirable to have the alkylmonosaccharide content less than about 10%.
As used herein, "alkylpolysaccharide surfactant" is intended to represent both the preferred glucose and galactose derived surfactants and the less preferred alkylpolysaccharide surfactants. Throughout this specification, "alkylpolyglycoside" is used because the stereo chemistry of the saccharide moiety is changed during the preparation reaction.
The alkylsaccharides of this invention, as formed in the reaction, contain colored materials. It is important that the reaction mix not contain appreciable amounts of water. Preferably there should be less than about 2% water, and more preferably less than about 0.5% water, in the reaction mix. The invention allows the facile removal of the colored materials by a simple solvent extraction using from about 50% to about 1000%, preferably from about 100% to about 500%, more preferably from about 200% to about 300% of the polar solvent described hereinbefore. The solvent is mixed with the alkylsaccharide reaction mixture and then removed, typically by a simple decantation. Then, preferably, the solvent is boiled off and recycled.
The presence of more than about 10% water prevents the removal of the color bodies. In fact, once water is added to the reaction mixture, it is extremely difficult, or impossible, to extract the colored materials. Small amounts of nonpolar solvents are acceptable and even desirable, especially when it is desired to adjust the overall solvent polarity.
All parts, percentages, and ratios herein are by weight unless otherwise stated.
The following examples illustrate the practice of the invention.
EXAMPLE I
A dark colored reaction product mixture having a transmittance value of 2% at 470 nm in a 2 cm. cell, containing 45% alkyl polyglycosides and 55% Neodol 23 alcohol was mixed with 3 volumes of dry acetone having a dipole moment (polarity) of 2.8 and a boiling point of 56° C. A white precipitate formed from the brown colored acetone/fatty alcohol solution. This precipitate was collected by decantation and further washed with small amounts of acetone to remove residual solvents. The sediment was dried in a vacuum oven for 2 hours at 50° C. and 2 cm Hg pressure. The resulting cake was finely ground and used as surfactant without bleaching. The acetone solutions were distilled to recover the solvent. The residual fatty alcohol with some dissolved alkyl monoglucoside was recycled. A 45% solution in water of the product had a transmittance value of 33% at 470 nm in a 2 cm cell.
EXAMPLE II
A similar reaction mixture was washed with a 75/25 mixture of acetone and hexane, having a polarity of about 2.1 and boiling point between about 56° C. and about 64° C. This solvent mixture precipitates more of the alkyl monoglucoside than the 100% acetone.
EXAMPLE III
A 90/10 mixture of ethyl acetate and acetone, having a polarity of about 1.9 and boiling point between about 56° C. and about 68° C., was used in the procedure and generated material essentially the same in quality as in Example I.
EXAMPLE IV
The same reaction mixture was first distilled to remove most of the excess Neodol 23 using a Pope, 2 inch wiped film molecular still. The residual reaction mixture was then dissolved in one volume of hot hexane and then precipitated by adding 3 volumes of dry acetone giving the solvent mixture of Example II. The product was dried and gave a pure white powder.
EXAMPLE V
The 45/55 glycosides/fatty alcohol reaction mixture of Example I was washed with acetone with various amounts of water. The product yield was found to decrease when more than about 0.5% water is present in acetone.
EXAMPLE VI
The excess fatty alcohol of the reaction mixture of Example I was first removed through an Aldrich Kugelrohr distillation unit, Catalog No. Z10,046-3. The resulting product was ground into a fine powder which was dark brown in color. It was then extracted with dry acetone in a soxhlet extractor overnight. This completely removes the color bodies.
COMPARATIVE EXAMPLE VII
Triton BG-10, a 70% water solution of alkyl glycosides (Rohm & Haas product) was mixed with 3 volumes of acetone, no precipitate was formed. The presence of water changes the solvent polarity and dissolves the alkyl glycosides.
EXAMPLE VIII
The same reaction mixture of Example I was mixed with 2 volumes of dry acetone. The mixture was refluxed overnight. The solution of fatty alcohol in acetone was filtered. The residual reaction mixture was further washed with 0.5 volume of acetone and dried. This gave a cake with little color. | A process for removing colored materials from alkylpolysaccharides by extracting the colored materials with polar solvents under essentially anhydrous conditions. | 2 |
BACKGROUND OF THE INVENTION
[0001] Human beings have long been interested in predictions of what the future will be. In recent centuries, mathematicians have succeeded in finding methods of prediction for a very limited range of phenomena. If the predicted entity is a measurable quantity, it is possible to estimate the magnitude of the quantity at a future time, given its magnitude at previous times, if the measured quantity changes smoothly, i.e., has no sudden changes. A mathematician would call such a smoothly varying quantity an “analytic” function of the time.
[0002] Brook Taylor, an English mathematician, was among the first to invent such a method, nearly three centuries ago, in 1715. Taylor's formula calculates the value of a smoothly-varying quantity f at a future time t from from knowledge of the quantity at a previous time t 0 . The formula uses the value of the quantity at time t 0 and its derivatives at t 0 . The need to know the derivatives of the quantity limits the formula's usefulness. Sometimes it is possible to calculate the analytic form of these derivatives, but this requires knowledge of the analytic form of the quantity itself. In many situations, one does not have this information.
[0003] There are many other methods for estimating the value of a quantity at a future time from its values at previous times. Some other methods rely on adjusting parameters (i.e., constants) of an analytic expression, which is assumed to accurately characterize the quantity. Such methods include mean-square curve-fitting and the maximum likelihood method, which are described in many textbooks. The parameters to be adjusted might include slope and intercept (in the case of a line), or standard error and central value (in the case of a probability distribution). However, these methods, like Taylor series, assume that one knows the analytic form of the quantity (e.g., a line or bell-shaped curve). They are not useful if the analytic form of the quantity is not known.
[0004] Recently researchers have learned to use neural networks to predict future signal values. The neural network is “trained” on previous data. Neural networks can sometimes produce reasonable results for non-smooth signals, such as a sawtooth signal. As applied, however, neural networks are often trained to recognize expected patterns in the signal, such as frequency components or wavelet patterns.
SUMMARY OF THE INVENTION
[0005] The present invention is a system and method that can predict an estimate of the future value of a smooth signal from prior values, without any knowledge of the form of the signal. The system measures signal values at a baseline time and at a collection of succeeding times. The baseline time is the time at which the first measurement of the signal is made. The time increments—from the baseline time to each of the succeeding measurement times—form sets of geometric sequences. Although the method requires a large number of signal measurements, the processing that produces the prediction is quite simple. The method calculates the predicted signal value merely by multiplying and dividing the prior measured signal values. By repetition, the method is capable of producing an output signal: a continuing stream of signal predictions, which approximates periodic samples of the future signal “pulled back” in time.
DESCRIPTION OF THE DRAWING
[0006] The present invention will hereafter be described with reference to the accompanying drawings, of which:
[0007] FIG. 1 is a block diagram of one embodiment of a Signal Prediction System, which is comprised of a Prediction Controller (PC), multiple Geometric Sampling Units (GSUs) and a Prediction Accumulation Multiplier (PAM);
[0008] FIG. 2 is a description of the method followed by the Prediction Controller;— FIG. 3 is a description of the method followed by each Geometric Sampling Unit;
[0009] FIG. 4 is a description of the method followed by the Prediction Accumulation Multiplier; and— FIG. 5 is an example output of the method, calculating the future value of a sinusoidal function.
DESCRIPTION OF THE INVENTION
[0010] The invention is a system and method that predicts an estimate of a future value of a signal from prior measured values of the signal. The times when the signal is measured include a baseline time and a collection of incrementally subsequent times. The baseline time is the time at which the first measurement of the signal is made. The time increments—from the baseline time to each of the succeeding measurement times—form sets of geometric sequences. The predicted future value of the signal is obtained merely by multiplying and dividing the prior measured signal values.
[0011] The mathematical basis for the method is a theorem in mathematical analysis that was discovered by the inventor. The method applies only to signals that are not negative. However, a bounded signal that takes on negative values can be adapted for the method, by adding to the signal a sufficiently-large positive bias.
System Architecture
[0012] One example embodiment of the system, which we call the Signal Prediction System (SPS) is shown in FIG. 1 . The architecture of the SPS closely parallels the structure of the method. The SPS 101 comprises a Prediction Controller (PC) 102 , multiple Geometric Sampling Units (GSUs), e.g. 103 , and a Prediction Accumulation Multiplier (PAM) 105 .
[0013] The PC accepts user input parameters, and distributes to the PAM and to each of a number of GSUs, the parameters they require for the prediction. The system comprises at least one GSU for each geometric sequence of measurement times used by the method. The basic functions of a GSU are to measure the signal values at the baseline time and the subsequent times for one geometric sequence, normalize each value, raise each normalized value to an appropriate power, and report the result or its inverse to the PAM. Each GSU has access to the signal 104 whose future value is to be predicted, and has means to measure the magnitude of the signal. The PAM multiplies the values received from the GSUs, keeping track of when the GSUs have all indicated that they have finished reporting the results of their measurements. When this occurs, the PAM outputs its product, which is the predicted future value of the signal. The process may then be repeated, if the user desires a continuing stream of periodic signal predictions. The number of geometric sequences to be used, the measurement times appropriate to each geometric sequence, and the appropriate exponent to be used in calculating the result of each measurement, are described below.
Process of the Prediction Controller
[0014] FIG. 2 is a flowchart of the method followed by the Prediction Controller. The method uses several parameters input by the user of the SPS, and other parameters calculated therefrom by the PC that are used by the GSUs and the PAM.
[0015] In step 201 , the PC collects parameters input by the user of the SPS. They include the following:
M is a positive integer that determines the number of geometric sequences of time increments used in the prediction. The number of geometric sequences used by the method is 2 M −1. Since there is one GSU for each geometric sequence, the SPS must contain at least 2 M −1 GSUs to make the prediction. M is an optional user input. If the user does not provide a value, the PC uses a default value, equal to log 2 (N GSU +1), where N GSU is the largest integer equal to one less than a power of two, and is also less than or equal to the number of GSUs in the system. N is a positive integer that determines the number of time increments in each of the geometric sequences. N cycle is the number of consecutive signal predictions requested by the user. A negative value for N cycle is interpreted by the SPS as a request for an unending stream of successive periodic signal predictions. t 0 is the baseline time of the first signal measurement used in the prediction. Δs, the sampling interval, is the length of time during which the signal will be sampled for one prediction. The last signal measurement during one cycle is made at time t 0 +Δs. Δp, the prediction interval, is the length of time between when the last signal measurement is made and the future time for which the value of the signal is being predicted. ΔT cycle is the time requested between successive periodic signal predictions.
From the user input, the PC in step 202 calculates:
N GSU =2 M −1, the number of GSUs to be used for the requested prediction; P=1+Δp/Δs, a measure of the power or range of the prediction, used solely to calculate the geometric ratio r; r=P/(P M −1) 1/M , the common geometric ratio of all the geometric sequences used in the prediction; and Δt=Δs+Δp, the time between the baseline time t 0 and the time for which the future value of the signal is being predicted.
[0027] In step 203 the PC sends to each of the N GSU GSUs participating in the prediction the following parameters: N, N cycle , r, t 0 , Δt, and ΔT cycle .
[0028] In step 204 the PC generates all of the non-empty subsets of the first M positive integers, including the so-called improper subset containing all M integers; the PC assigns a unique subset to each of N GSU GSUs; and the PC sends that subset to its GSU. For the k th GSU, this subset, called its generating set, will be referred to as S k . The post-baseline geometric sequence of times when the GSU measures the signal depends upon its generating set. FIG. 1 illustrates the case of M=3, in which 7 GSUs are required; each GSU is labeled with its generating set of integers.
[0029] Finally, the PC sends to the PAM the parameters it requires: N GSU , N cycle , t 0 , Δt, and ΔT cycle .
Process of the Geometric Sampling Unit
[0030] FIG. 3 is a flowchart of the method followed by the k th Geometric Sampling Unit.
[0031] In step 301 the GSU receives the parameters sent to it by the PC. In step 302 the GSU receives S k , the unique generating set of integers assigned by the PC to the k th GSU.
[0032] In step 303 , the GSU calculates the geometric sequence of time increments Δt k,n that will be added to t 0 form its set of measurement times beyond t 0 . The time increments are given by Δt k,n =Q k ·Δt·r n /r N+1 , where Q=Π j∈S k (r j −1) 1/j , |S k | is the number of integers in the set S k , and the index n runs from 1 to N−|S k |+1.
[0033] The GSU keeps a count of two things: n cycle , counts how many cycles of measurements have been started, and n counts the number of the time increments used so far by a GSU in each measurement cycle. A cycle is the process for making all of the measurements, and doing all of the calculations, required for a single signal prediction. In step 304 , the GSU initializes n cycle . In step 305 , the GSU increments n cycle , and initializes n.
[0034] In step 306 , the GSU waits for the current time t to equal time the t 0 , whereupon in step 307 it measures the magnitude of the signal v 0 at the time t 0 .
[0035] Most of the signal measurements are normalized, by dividing them by v 0 . But the predicted signal value requires one unnormalized factor of v 0 in its numerator. This is accomplished by each GSU in step 308 testing whether its generating set is equal to {1}. Only the unique GSU that passes this test sends the value f=v 0 to the PAM, along with a flag value of zero, in step 309 . A flag value of zero indicates to the PAM that the GSU is not yet done sending all of its signal prediction factors for the current measurement cycle to the PAM.
[0036] In step 310 the GSU increments n, beginning the process of measuring the signal for the n th time increment beyond t 0 . In step 311 the GSU waits until the current time t reaches t 0 +Δt k,n , the time associated with the n th time increment of the k th geometric sequence; at that time it measures the magnitude of the signal v k,n in step 312 . In step 313 the GSU tests whether the number of integers in its generating set, |S k |, is odd or even. If it is odd, in step 314 the GSU calculates the next prediction factor f that it will send to the PAM, by calculating the normalized signal value, v k,n /v 0 , and raising it to the power given by the binomial coefficient
[0000]
(
N
-
1
s
k
-
1
)
.
[0000] If it is even, in step 315 the GSU calculates the next prediction factor f that it will send to the PAM, by calculating the inverse of the normalized signal value, v 0 /v k,n , and raising it to the power given by the binomial coefficient
[0000]
(
N
-
1
s
k
-
1
)
.
[0037] In step 316 the GSU compares n, the number of post-t 0 measurements that have been made, with the number of such measurements that are to be made in the current measurement cycle, N−|S k |+1. If they are not equal, in step 317 the GSU sends the prediction factor f to the PAM with a flag value of zero; it then loops back to step 310 to begin the next signal measurement of the cycle. If they are equal, in step 318 the GSU sends the prediction factor f to the PAM with a flag value of one, and proceeds to step 319 . A flag value of one indicates to the PAM that the GSU has finished reporting its prediction factors.
[0038] At step 319 the GSU checks whether the count of completed measurement cycles, n cycle , equals the number to be done, N cycle . If so, the GSU stops. If not, in step 320 the GSU increments t 0 by ΔT cycle , and loops back to step 305 to begin the next measurement cycle. Note that if the user inputs a negative value for N cycle , the GSU will always loop back to step 305 , and the GSU will report a continuing stream of signal prediction factors to the PAM.
Process of the Prediction Accumulation Multiplier
[0039] FIG. 4 is a flowchart of the method followed by the Prediction Accumulation Multiplier.
[0040] The process of the PAM begins in step 401 when it receives from the PC the parameters N GSU , N cycle , t 0 , Δt, and ΔT cycle . In step 402 the PAM calculates t p =t 0 +Δt, the future time for which the prediction of the signal is to be made. In step 403 the PAM initializes n cycle to zero, which it increments in step 404 . In step 404 the PAM also initializes n done to zero; n done counts the number of GSUs that have finished reporting the results of their measurements to the PAM for the current cycle.
[0041] In step 404 the PAM also initializes the quantity v p to unity. The purpose of the PAM is to produce the predicted value of the signal v p at time t p . The PAM incorporates all of the factors of the predicted signal value, which are sent to it by the GSUs, into the quantity v p —including the single factor of v 0 . The PAM does so by multiplying the current value of v p serially by each factor received; therefore, the value of v p is initialized to unity.
[0042] In step 405 the PAM receives two values, f and a flag value, from a GSU. In step 406 the PAM multiplies the current value of v p by this factor, thereby incorporating this factor into the prediction. In step 407 the PAM checks whether this factor is the last to be received during this measurement cycle from the GSU that sent it. If the flag value is zero, it is not, and the PAM loops back to step 405 to receive the next factor sent by a GSU. If the flag value is one, this is the last factor to be received from this GSU in the current cycle; and the PAM proceeds to step 408 , in which it increments n done , the count of GSPs that are done with this cycle of measurements.
[0043] In step 409 the PAM compares the number of GSUs that are done with the number of GSUs participating in the prediction. If they are not equal, the PAM returns to step 405 to receive the next factor sent by a GSU that is not yet done. If all GSUs are finished reporting their measurement factors, in step 410 the PAM outputs two values: v p , the predicted signal value, and the time t p for which v p is the predicted value.
[0044] In step 411 the PAM checks whether the number of cycles completed is equal to the number of cycles to be performed. If so, the PAM stops; if not, it increments both t 0 and t p by ΔT cycle , in step 412 , before looping back to step 404 to begin the next cycle. If the user has input a negative value for N cycle , the PAM always proceeds from step 411 to step 412 , and will produce a continuing stream of periodic signal predictions and their times.
Example Output
[0045] FIG. 5 is an example of the output of the method. The method was used to calculate the future value of an analytic function, namely f(t)=1+(½)sin (t). The solid line is the function f. The dashed line is the pullback of the function f, namely f(t+p). The dots on the dashed line are predictions of future values of the function f, calculated using the method of the present invention. The dots on the solid line are values of the function itself. Observe that (1) the predicted values of the function do, in fact, lie on the pullback's dotted line, and (2) the value of the ordinate at these times is equal to the corresponding value of the function itself, a time interval p later. The prediction uses the values M=4, Δs=π/6, Δp=π/12, and N=500. The predictions have a time spacing equal to Δs, as they would have if the method were used on an actual signal to produce a stream of predictions, with sampling interval Δs. The calculations and graphs were produced using Mathematica.
[0046] Other embodiments of the invention will be apparent from the foregoing description to those of ordinary skill in the art, and such embodiments are likewise to be considered within the scope of the invention as set out in the appended claims. | A method and system are described that can predict the future value of a positive signal from prior measured values of the signal. The signal is measured at a prior baseline time, and at times incrementally beyond the baseline time. The post-baseline time increments comprise sets of geometric sequences. The system produces a future estimate of the signal merely by multiplying and dividing prior signal values. By repeated operation, the system can produce an output signal: a continuing stream of periodic signal predictions, which approximates periodic samples of the future signal “pulled back” in time. | 6 |
FIELD
The invention relates to methods to control the delivery of fluids for use in oilfield applications for subterranean formations. More particularly, the invention relates to controlling the fluid temperature.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
This invention relates to fluids used in treating a subterranean formation. The pumping of treatment fluids, such as acids or other types of fluids and chemicals is routinely conducted in oil and gas production wells and in water injection wells to enhance either hydrocarbon production or water injection. During the injection of the treatment, the fluids flow down the wellbore and reach the target geological zones at a certain downhole injection temperature which depends on many factors such as the surface temperature, the initial geothermal profile between the surface and downhole, the pump rate, the geometry of the wellbore and the thermal properties of the fluids, completion materials, and rocks in the subterranean formations. Control of the downhole injection temperature is desirable to efficiently tailor the effectiveness and other parameters of the treatment.
SUMMARY
Embodiments of the invention provide methods and apparatus for using a fluid within a subterranean formation comprising forming a fluid comprising a fluid additive, introducing the fluid to a formation, observing a temperature, and controlling a rate of fluid introduction using the observed temperature, wherein the observed temperature is lower than if no observing and controlling occurred. Embodiments of the invention provide methods and apparatus to deliver fluid to a subterranean formation comprising a pump configured to deliver fluid to a wellbore, a flow path configured to receive fluid from the pump, a bottom hole assembly comprising a fluid outlet and a temperature sensor and configured to receive fluid from the flow path, and a controller configured to accept information from the temperature sensor and to send a signal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of surface equipment and a bottom hole assembly.
FIG. 2 is a schematic diagram of details of a bottom hole assembly.
FIG. 3 is a flow diagram of a process of embodiments of the invention.
FIG. 4 is a plot of the Joules Thompson coefficient as a function of pressure and temperature for carbon dioxide.
FIG. 5 is a plot of temperature variation in the gas phase as a function of pressure and temperature for carbon dioxide.
FIG. 6 is a plot of temperature variation of the mixture during the Joule Thomson (JT) effect as a function of pressure and temperature for carbon dioxide.
FIG. 7 is a plot of the temperature in the gas phase as a function of pressure and temperature for carbon dioxide.
FIG. 8 is a plot of temperature variation of the mixture during the JT effect as a function of pressure and temperature for carbon dioxide.
FIG. 9 is a plot of the temperature in the gas phase as a function of pressure and temperature for carbon dioxide.
FIG. 10 is a plot of temperature variation of the mixture during the JT effect as a function of pressure and temperature for carbon dioxide.
DETAILED DESCRIPTION
The procedural techniques for pumping fluids down a wellbore to fracture a subterranean formation are well known. The person that designs such treatments is the person of ordinary skill to whom this disclosure is directed. That person has available many useful tools to help design and implement the treatments, including computer programs for simulation of treatments.
In the summary of the invention and this description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary of the invention and this detailed description, it should be understood that a concentration range listed or described as being useful, suitable, or the like, is intended that any and every concentration within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific numbers, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors have disclosed and enabled the entire range and all points within the range. All percents, parts, and ratios herein are by weight unless specifically noted otherwise.
Temperature control along a surface of a subterranean formation is important when acid is injected into the reservoir rock around the wellbore to increase production rate. The acid efficiency depends on the acid temperature and it may be desirable to decrease the downhole injection temperature to ensure better acid performance. Another example is the determination of the geological zones that are accepting the injected fluid and those that are not which may be achieved by using distributed temperature sensors (DTS). If the downhole injection temperature is sufficiently low/high, then zones of higher injectivity will show larger warmback/cooldown times if the well is shut in after the treatment. The warmback/cooldown time is the time it takes during the shut-in for the temperature of a given zone to come back to its original value before treatment. The measure of the warmback/cooldown time becomes more accurate if the downhole injection temperature is lower/higher than otherwise achieved.
One means of changing the downhole injection temperature is to expose the fluid to a pressure drop caused by fluid expansion. The laws of thermodynamics predict that, under such a process, fluids may either reduce or increase their temperature through an effect named the Joule Thomson (JT) effect. Embodiments of the invention relate to a method of controlling downhole injection temperature by taking advantage of this effect through the combined use of pump rate, a bottom hole assembly (BHA), additives to the fluids and downhole temperature sensors.
For certain types of applications, the functionality and the performance of the injected fluid may depend on the downhole injection temperature. In other types of applications, it may be desirable to modify the downhole injection temperature in such a way that some downhole measurements used for interpreting the treatment fluid performance may be optimized. The JT effect and its influence on the downhole temperature during the production of reservoir fluids have been investigated by many authors. However, the controlled use of the JT effect to accomplish the goal of changing the downhole injection temperature of the injected fluid for a given purpose has not been pursued historically.
Historically, a method changes the temperature of the fluid in the wellbore using the JT effect of a gas that would change the temperature of a heat exchanger. The wellbore fluid flowing in contact with the heat exchanger would have its temperature changed by heat transfer between the heat exchanger and the wellbore fluid. The method proposed here is significantly different as it uses the JT effect of the injected fluid itself and therefore does not require a heat exchanger. Historical methods do not deal with changing the downhole injection temperature to control the functionality of the injected fluid and only measure its properties.
The JT effect can occur during the production of a gas when the later experiences a significant pressure drop when going from the reservoir rock into the well. In most situations, the gas will experience a temperature drop during the pressure drop. This temperature drop may be detected by downhole temperature gages, such as those on production logging tools or distributed temperature sensors and may help an engineer identify the regions along the wellbore from which gas is being produced. Additionally, as the gas moves up to the surface production facility, its pressure will decrease and the JT effect will often result in a reduced gas temperature.
Additional embodiments of the invention control a temperature change during injection, into the well through the JT effect. Methods comprise using a tool and a control process which can be used for changing the downhole injection temperature through the JT effect during the pumping of a fluid treatment in a well.
If it is estimated or known by measurement that the fluid being pumped for a specific purpose, such as reservoir stimulation, chemical treatment, and enhanced oil recovery, does not have the required downhole injection temperature, either for its own performance or for the accuracy of the downhole temperature-based interpretation of the treatment performance, placing a device along its flow path will cause a pressure drop in the fluid. This pressure drop will change the downhole injection temperature through the JT effect. By being able to measure or predict the down hole injection temperature and to control the pump rate, the down hole injection temperature may be adjusted to the required temperature. The down hole injection temperature response to the pump rate may also be enhanced by introducing fluid additives, such as gases, to the pumped fluid.
The method has two parts:
1. The Tool: The physical device and products that cause a change in the down hole injection temperature 2. The Control Process: The methodology for optimizing the use of the tool
A down hole injection temperature change may be achieved by three means:
1. The characteristics of the bottom hole assembly 2. The value of the pump rate 3. The use of fluid additives
For instance, the fluid may be pumped from the surface through a tubing or coiled-tubing at the end of which a bottom hole assembly may be placed. On the bottom hole assembly, a temperature sensor may be mounted. The ensemble formed by the pump, the flow path, typically the drill pipe or coiled tubing, the bottom hole assembly, the temperature sensor, and the fluid additives, is referred as the tool and is used as part of the method. The bottom hole assembly of the tool may have some remotely controlled flow devices or orifices which, for a given pump rate, may control the pressure drop that the fluid will undergo when leaving the bottom hole assembly into the wellbore before flowing into the reservoir. The down hole injection temperature may also be monitored using downhole temperature sensors not mounted on the bottom hole assembly. For instance, the down hole injection temperature may be measured using down hole temperature sensors deployed in the wellbore before or during the pumping. Finally, if down hole temperature sensors are not available, the down hole injection temperature may be predicted using a mathematical model capable of solving the relevant thermodynamics problem for the treatment fluid undergoing expansion through the controlled flow devices or orifices.
Using the down hole injection temperature data measured by the temperature sensors on the bottom hole assembly, or measured with other down hole temperature sensors, or predicted by the model, some adjustment of the pump rate and of the tool may be decided during the pumping. This decision tree is referred as the control process and is the second part of the method. It is illustrated in FIG. 3 . For instance, the controlled flow devices may be valves which can be closed or open to increase or reduce the pressure drop. Additionally; the fluid additive may be a gas that is pumped with the fluid to optimize the value of the JT coefficient of the gas-fluid mixture. Alternatively, gas on its own may be pumped towards the end of the treatment for further control on the down hole injection temperature through increased JT effect.
A combined use of the tool and the control process will help engineers ensuring that the down hole injection temperature meets the requirements.
FIG. 1 illustrates one embodiment of the mechanical equipment that may be used. The pumping is performed using a fluid pump 101 on surface 102 . The treatment fluid and the fluid additive are stored in their own fluid tanks 103 and 104 and flow through the pump 101 at a rate and proportion controlled by the engineer. The mixture, formed by the treatment fluid and the fluid additive, then flows through surface lines 105 and then down into the wellbore 107 through a flow path 106 , typically production tubing, the casing, a drill pipe, or coiled tubing. At the end of the flow path 106 , the fluid enters the bottom hole assembly 108 . The bottom hole assembly 108 has multiple orifices 109 that may be closed or open remotely by the engineer. When flowing through an orifice, as represented in FIG. 3 , the fluid undergoes a pressure drop. The extent of the pressure drop is controlled by the following.
The pump rate The number of orifices open to flow The amount of fluid additive
The pressure drop causes the fluid to undergo a change in down hole injection temperature as it leaves the bottom hole assembly 108 and flows into the reservoir 111 . This change in down hole injection temperature may be monitored at the surface by using the temperature reading from temperature sensors 110 through wireline communication or fiber optic cable. Alternatively, the down hole injection temperature may be obtained by other down hole temperature sensors (not shown) such as a distributed temperature sensors or be predicted by a mathematical model. In any event, controller 112 may receive a signal from or send a signal to the bottom hole assembly, temperature sensor, pump, additive or fluid tanks, or lines connecting the tanks, pump, flow path, or assembly. Finally, the engineer may change some of the above three parameters to optimize the down hole injection temperature.
FIG. 2 is a schematic diagram of details of a bottom hole assembly 108 in a wellbore 107 . The fluid flows through the flow path 106 to the assembly 108 with a pressure drop illustrated by flow lines 201 . FIG. 2 shows flow lines 201 are present on open valves 202 , but not on closed valves 203 . Temperature sensors 204 may also be placed across the surface of or embedded in or suspended near the assembly 108 .
In the case where the down hole injection temperature must be controlled for the accuracy of the down hole temperature-based interpretation of the treatment performance, it is also possible to pump another fluid than the treatment fluid, on its own, in order to achieve the required down hole injection temperature. For instance, if it is estimated that, under the conditions under consideration, the down hole injection temperature may not be controlled by pumping the treatment fluid, another fluid may be pumped at some stages in order to achieve the required down hole injection temperature for some time and to allow more accurate interpretation. For instance, at the end of an acid treatment, a gas may be pumped after the acids to achieve a larger change on the down hole injection temperature. This larger change on the down hole injection temperature will allow a more accurate interpretation concerning the event associated with the gas injection, which may be a direct consequence of the treatment performance. For instance, after having pumped the acid, the inflow profile along the well is what determines the acid treatment performance. Pumping a gas after the acid, with an optimum down hole injection temperature will reveal the inflow profile during gas injection. The inflow profile during gas injection being a consequence of the performance of the acid, the acid performance may be estimated. After pumping the gas, the pump rate is set to zero and the well is shut-in while a distributed temperature sensor is logged. Looking at how fast the down hole temperature at a given depth warms back to the temperature before the treatment reveals how much was injected. Alternatively, the position of a gas slug, with a lower down hole injection temperature along the well may be monitored by distributed temperature sensors revealing which zones are accepting fluid during the pumping. The use of temperature logging such as distributed temperature sensors or a down hole temperature on a moving tool as a means to identify injectivity profiles based on a down hole injection temperature significantly different from the reservoir temperature is important to some embodiments.
The following thermodynamic calculations may be performed to determine the down hole injection temperature as a function of the above three parameters. These calculations validate the concept of the use of the JT effect and may be used as a means of predicting the down hole injection temperature change with the pressure drop. The value of the pressure drop that the fluid will undergo when flowing through the orifices can be determined using Equation (1) and Equation (2):
PD
=
1
2
c
2
(
1
-
β
4
)
ρ
F
(
V
)
2
(
1
)
β
=
d
u
d
o
,
V
=
PR
A
d
=
PR
1
4
n
o
π
d
0
2
(
2
)
PD is the Pressure prop (Pa)
V is the fluid flow velocity (m/s)
c is the dimensionless discharge coefficient
d u Is the upstream diameter (m)
d o is the orifice diameter (m)
ρ F is the fluid density (kg/m 3 )
A d is the surface flow area formed by all n o open orifices (m 2 )
n o is the number of orifices open to flow
If the fluid additive is a gas, the two fluids will undergo a different pressure drop, PD F for the treatment fluid and PD G for the gas, as described by Equation (3) and Equation
PD
G
=
1
2
c
2
(
1
-
β
4
)
ρ
G
(
Vq
)
2
.
(
4
)
PD
F
=
1
2
c
2
(
1
-
β
4
)
ρ
F
(
V
(
1
-
q
)
)
2
(
3
)
PD
G
=
1
2
c
2
(
1
-
β
4
)
ρ
G
(
Vq
)
2
(
4
)
q is the volume fraction of gas in the mixture formed by the fluid and the gas
ρ G is the gas density (kg/m 3 )
In the general case where the fluid additive is a gas, both fluids phases will undergo a change in down hole injection temperature, denoted DTF for the treatment fluid and DTG for the gas additive, as given by Equation (5) and Equation (6).
DT
F
=
∫
BHP
+
DP
F
BHP
η
F
(
p
,
T
F
)
ⅆ
p
(
5
)
DT
G
=
∫
BHP
+
DP
G
BHP
η
G
(
p
,
T
G
)
ⅆ
p
(
6
)
DT G is the temperature variation in the gas phase (K)
DT F is the temperature variation in the fluid phase (K)
η G is the gas Joule-Thomson coefficient (K/Pa)
η F is the treatment fluid Joule-Thomson coefficient (K/Pa)
BHP is the DH pressure in the wellbore (Pa)
T G is the temperature in the gas phase (K)
T F is the temperature in the fluid phase (K)
p is the pressure (Pa)
The final value of the down hole injection temperature of the mixture formed by the treatment fluid and the gas can be determined using Equation (7).
DHIT
=
T
I
+
DT
GF
=
T
I
+
q
ρ
G
C
pG
(
T
I
+
DT
G
)
+
(
1
-
q
)
ρ
F
C
p
F
(
T
I
+
DT
F
)
q
ρ
G
C
pG
+
(
1
-
q
)
ρ
F
C
p
F
(
7
)
DHIT is the DH Injection Temperature (K)
DT GF is the temperature variation of the mixture during the JT effect (K)
C pG is the heat capacity of the gas (J/(kg K))
C pF is the heat capacity of the fluid (J/(kg K))
T I is the initial temperature of the mixture in the BHA, before flowing through the orifices (K)
The physical and thermodynamic properties of the treatment fluid and the gas, ρ F , ρ G , C pG , C pF , C pG , η F , η G , are functions of the temperature and pressure. It is possible to determine those properties from an equation of state. An equation of state links the value of the fluid density, fluid temperature and pressure together. The determination of an equation of state for a given fluid or gas has been the subject of a vast amount of literature. For instance, an equation of state such as the one from R. Span and W. Wagner, “A New Equation of State for carbon Dioxide Covering the Fluid Region from the Triple-Point to 1100K at Pressures up to 800 MPa”, J. Phys. Chem. Ref Data, 25(6), 1996 may be used for carbon dioxide.
It is also possible to determine physical and thermodynamic properties of the treatment fluid and the gas, ρ F , ρ G , C pG , C pF , C pG , η F , η G from experiments. Some of such experiments demonstrate the ability of certain fluids to undergo a temperature change during a JT effect. It is understood that during expansion, a fluid may experience heating, for a negative JT coefficient, or cooling for a positive one, and the scientific and technical literature provides numerous examples of the experimental values of the JT coefficient for numerous fluids. For instance, in J. R. Roebuck, H. Osterberg, “The Joule-Thomson Effect in Nitrogen”, Physical Review, 48, 1935, and J. R. Roebuck et al, “The Joule-Thomson Effect in Carbon Dioxide”, J. Am. Chem. Soc., 64, 1947, the values of the JT coefficient have been measured experimentally for nitrogen, and carbon dioxide, under various conditions in temperature and pressure, and the experimental data reported in these references, respectively, show that the JT coefficient may be positive or negative, highlighting zones of cooling and zones of heating respectively for these fluids.
The method is now illustrated in the case where the treatment fluid is an aqueous acid and the fluid additive is carbon dioxide (CO 2 ). Considering a 15 weight percent hydrochloric acid (15% HCl) solution being pumped with CO 2 with a down hole foam quality q equal to 0.5, the down hole injection temperature may be determined using Equations (1) to (7) and by using an equation of state for CO 2 as follows. First, and for the purpose of this example, the treatment fluid, 15% HCl, being a liquid, the variations of ρ F , C pF , and η F , during the flow through the orifices are negligible. The following values are reasonable approximations:
ρ
F
=
1070
kg
/
m
3
,
C
p
F
=
4200
J
/
(
kg
F
)
,
η
F
=
-
1
ρ
F
C
p
F
=
-
2.23
×
10
-
7
K
/
Pa
(
8
)
For CO 2 , the determination of DT G requires computing Equation
DT G = ∫ BHP + DP G BHP η G ( p , T G ) ⅆ p ( 6 )
along the expansion path experienced by the gas. This may be done using numerical approximations as described by Equations (9) to (13) as, typically, the equation of state is a too complex formula to allow the integration in Equation (6) to be done by hand.
DT
G
=
lim
N
->
∞
[
∑
i
=
1
,
N
[
δ
p
N
C
pG
(
p
i
,
T
Gi
)
(
T
Gi
∂
v
∂
T
(
p
i
,
T
Gi
)
-
v
G
(
p
i
,
T
Gi
)
)
]
]
(
9
)
v
G
(
p
i
,
T
Gi
)
=
1
ρ
G
(
p
i
,
T
Gi
)
(
10
)
δ
p
N
=
PD
N
(
11
)
p
i
=
p
i
-
1
+
δ
p
N
(
12
)
T
Gi
=
T
Gi
-
1
+
[
δ
p
N
C
pG
(
p
i
-
1
,
T
Gi
-
1
)
(
T
Gi
-
1
∂
v
∂
T
(
p
i
-
1
,
T
Gi
-
1
)
-
v
G
(
p
i
-
1
,
T
Gi
-
1
)
)
]
(
13
)
Equations (9) to (13) can be solved using a large value for N. This large value N may be determined by solving Equations (9) to (13) with increasing values of N until the result does not change significantly when N becomes larger. To solve Equations (9) to (13), it is possible to specify the final value of the pressure during the expansion, bottom hole pressure and the initial temperature in the bottom hole assembly before the expansion, T I .
T G1 =T I (14)
p N =BHP (15)
Equations (9)-(15) solve the temperature evolution in the gas as it expands by expanding the gas by very small expansion steps and adding the effect of all the smaller steps until the final pressure drop is reached. To be able to do so, the determination of the specific volume ν G must be detailed. This requires the use of an equation of state for CO 2 . Typically, an equation of state provides an explicit expression of the pressure, given a value of the temperature and specific volume ν G :
p =EOS(ν G ,T G ) (16)
However, determining ν G from the values of p and T G requires solving a non-linear equation. This may be done easily by using conventional optimization algorithms such as the Newton method or the dichotomy method.
The problem consisting of solving Equations (9)-(16) has been solved using the equation of state from R. Span and W. Wagner [4]. FIG. 8 illustrate the values of DT G as a function of the final pressure after expansion (BHP) and the initial temperature before expansion T I . In FIG. 5 , the value of η G is plotted for various values of pressure and temperature. The fact that η G is positive over a wide range of pressure and temperature shows that CO 2 cools down under the JT effect. Solving Equations (9) to (16), the changes of temperature in the gas (DT G ) and in the mixture (DT GF ) are plotted in FIG. 6 and FIG. 7 , respectively, for a value of pressure drop of −1000 PSI. Increasing the pressure drop to −2000 PSI, the fluids cool down further as plotted in FIG. 8 and FIG. 9 but the area affected by the cooling does not vary significantly. It can also be seen that the cooling of the gas is larger than the cooling of the mixture. Depending on the situation, gas alone may therefore be pumped for maximum cooling. It may also be seen that the pressure drop must be large enough for significant cooling to occur. When pressure drop=−100 PSI, the temperature change is much smaller ( FIG. 10 and FIG. 11 ) and therefore, if the engineer aims at cooling down by 5K, the pump rate and the controlled flow device must be controlled in such a way the pressure drop is closer to −1000 PSI.
EXAMPLES
The following examples are presented to illustrate the preparation and properties of fluid systems, and should not be construed to limit the scope of the invention, unless otherwise expressly indicated in the appended claims. All percentages, concentrations, ratios, parts, etc. are by weight unless otherwise noted or apparent from the context of their use.
FIG. 4 plots the value of the JT coefficient η G for CO2 as a function of pressure and temperature.
FIG. 5 plots the DT G for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −1000 PSI. Data truncated between −5K and +5K.
FIG. 6 is a plot of DT GF for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −1000 PSI. Data truncated between −5K and +5K. FIG. 7 is a plot of DT G for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −2000 PSI. FIG. 8 is a plot of Data truncated between −5K and +5K. FIG. 8 plots DT GF for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −2000 PSI. Data truncated between −5K and +5K. FIG. 9 is a plot of DT G for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −100 PSI. Data truncated between −5K and +5K. FIG. 10 is a plot of DT GF for CO2 for various initial temperature T I and pressure after JT effect (BHP) with a PD equal to −100 PSI. Data truncated between −5K and +5K
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below. | Methods and apparatus for using a fluid within a subterranean formation comprising forming a fluid comprising a fluid additive, introducing the fluid to a formation, observing a temperature, and controlling a rate of fluid introduction using the observed temperature, wherein the observed temperature is lower than if no observing and controlling occurred. A method and apparatus to deliver fluid to a subterranean formation comprising a pump configured to deliver fluid to a wellbore, a flow path configured to receive fluid from the pump, a bottom hole assembly comprising a fluid outlet and a temperature sensor and configured to receive fluid from the flow path, and a controller configured to accept information from the temperature sensor and to send a signal. | 4 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a Continuation-in-Part of application Ser. No. 09/169,099 filed Oct. 9, 1998, which is a Continuation in Part of Application Ser. No. 60/061,512, filed Oct. 10, 1997.
FIELD OF THE INVENTION
The present invention relates generally to timing devices for scheduling an event, and prompting a person to respond to the event. More particularly, though not exclusively, the present invention relates to a timing device having an attachable pill box and having a series of timers and alarms to be used for scheduling and reminding a person to take his or her medicine.
BACKGROUND OF THE INVENTION
Over the years, an entire family of pill boxes have been developed in order to assist people in remembering to take their medicine. For instance, small, pocketsized pill boxes have been around for generations and allow a person to fill their pill box with the medicine for the day and conveniently carry it with them. While these traditional pill boxes facilitate the transportation of medicines, a problem often arose when the person was required to take more than one kind of medicine during the day. In such circumstances, the person often may not be able to distinguish the different medicines, and thus, may take the medicine in incorrect dosages or at the wrong time intervals.
In response to this problem, a number of pill boxes were created which had different compartments for holding different medicines. Thus, at the time to take medicine, a person would only have to select the pills from the appropriate compartment. While this tended to minimize the level of confusion associated with taking different medicines, it did little to assist the person to remember when to take their medicine.
As technology has evolved over the last few decades, a large number of solutions have been tried in an effort to assist people with the painful task of remembering to take their medicine. One such solution was to create a pill box having an integral count-down timer. Using this device, a person could place his or her medicine within the pill box and set the count-down timer for a specific time interval, such as four (4) hours. Then, four (4) hours later, the count-down timer will sound and the person will be alerted to take the medicine. While this device provided an effective means to alert a person at the time to take the medicine, it provides no assistance to people having to take more than one medicine at different time intervals. In fact, since the count-down timer only accommodates a single time interval, it is useless for combinations of medicines having different administration times unless the user resets the count-down timer over and over again.
To overcome the multiple administration time problems associated with count-down timers, timers were developed having more than one count-down timer interval. Using these devices, a person could set a first count-down timer for four (4) hours, and a second count-down timer for eight (8) hours. When the first count-down timer sounded, the person could take his or her first dose of medicine, and when the second count-down timer sounded, the person could take his or her second dose of medicine. In circumstances where the pill box included more than one compartment, each of the timers could be associated with one or more of the compartments, and thus when the first timer sounds, medicine in one compartment may be taken, and when the second timer sounds, medicine in the other compartment may be taken.
While the pill boxes with count-down timers assisted the medicine-takers in remembering their medicine, these devices were ineffective in situations where the count-down timers would sound when the person was unable to take the medicine, such as during a meeting. However, since the person would need to quiet the timer immediately, the timer would be disabled, and then the person would once again have to rely on his or her memory to take the medicine following the meeting, for example.
In circumstances where the medicine cannot be taken when the timer sounds, a person's entire medicine schedule may become delayed. In addition, many existing devices do not monitor whether the medicine was taken, or at what time the medicine was taken.
Although some pill boxes with timers may assist people in remembering to take their medicine, unfortunately most of these devices must be re-programmed on a daily basis. This re-programming introduces the opportunity to make errors, and may be too difficult for the elderly.
Even if the pill box has the ability to remember a schedule of medicine from day to day, the person is still required to re-load the pill box compartments with the medicine for the day, and may result in the person not using the pill box, or making errors in the constant refilling of the compartments.
In light of the above, it would be advantageous to provide a pill box having a scheduling device capable of notifying a person when to take his or her medicine. It would also be advantageous to provide a pill box capable of tracking whether or not the person has in fact taken his or her medicine after the notification. Also, it would be advantageous to provide a pill box having the ability to notify and track more than one medicine administration, including medicines having different dosages and administration intervals.
It would also be advantageous to provide a pill box having a detachable timer device such that a number of pill boxes may be loaded with medicine at the same time. Thus, at the beginning of the week, the detachable timer device may be moved from pill box to pill box so that the person does not have to refill the pill box each day, thereby minimizing the likelihood of error in selecting the medicine, or in remembering to refill the box. This feature would be particularly advantageous for the elderly as they would no longer be responsible for selecting their medicine on a daily basis, but would be able to have an assistant load their pill boxes for the entire week at one time. Further, there is a need for information providing the time the last medicine was taken and whether a dose was missed or skipped.
SUMMARY OF THE INVENTION
The above noted problems, and others, are overcome by this invention, which comprises a box having multiple medicine compartments, each of which typically holds one or more pills, capsules or the like and a timing device capable of scheduling medicine administration, monitoring whether an administration schedule is followed, and alerting the user of an appropriate scheduled administration event.
The pill box of the present invention includes a number of medicine compartments. A pill splitter may be fastened to the pill box to permit pills to be divided as necessary. Each of the medicine compartments is equipped with a hinged, releasable, lid so that medicine may be placed in the compartment, the lid closed and the box safely transported. A latch for releasably locking the lid in the closed position is also included.
The timing device of the device includes a microprocessor programmed to facilitate the scheduling and administration of medicine. Specifically, the timing device is equipped with a number of timers and/or alarms, with each such timer and/or alarm corresponding to a single medicine compartment in the storage box. In this manner, when the timer and/or alarm corresponding to a particular medicine compartment is activated, the person can identify the appropriate time and dosage for that medicine. The alarm preferably has a volume control, so that the alarm can be made quite loud for use by those with impaired hearing. Each compartment may be filled once a week, once daily or whenever the compartment becomes empty, as desired.
Due to the detachable nature of the medicine storage box, the box may be separated from the timing device for individual use, or for periodically changing boxes, such as providing a different box for each day of the week, where numerous different medicines must be taken at different times each day. Also, in the event a large amount of medicine is consumed daily, a first storage box may be loaded with a morning supply of medicine and another box filled with the afternoon supply of medicine.
An important advantage of the present invention is the ability to associate the timer device with any number of storage boxes. Consequently, it is no longer necessary to reload a pill box every day, but rather the entire week's worth of medicine may be placed in series of seven different boxes. Each box may then be secured to the timing device in seriatim each day to provide the medicine for that day. Moreover, a care giver may preload this medicine for an elderly person, thereby eliminating the need for the person to organize his or her own medicine administration. Also, if desired the user can leave the medicine in the original bottle and the alarm number can be written on the bottle.
A wide variety of information is provided by the timer and alarm box. For example, in addition of alerting the user to times at which medicine should be taken, the timer box will inform the user when the last dose of each medicine was taken and how many doses have been missed or intentionally skipped. The display will tell the user when the next dose of each medicine is scheduled to be taken. If the user has not taken the medicine when an alarm has sounded, at a later time the user can look at the “next” indication and decide if it is safe to take a late dose or to wait for the next alarm for that medicine.
BRIEF DESCRIPTION OF THE DRAWINGS
The nature, objects, and advantages of the invention will become more apparent to those skilled in the art after considering the following detailed description in connection with the accompanying drawings, in which like reference numerals designate like parts throughout, and wherein:
FIG. 1 is an exploded perspective view of the pill box, timer and alarm box and optional pill splitter;
FIG. 2 is a perspective view of the operating face of the time and alarm box;
FIG. 3 is a plan view of the timer and alarm box showing switch button indicia; and
FIG. 4 is a schematic block diagram of the componenst of the timing and alarm mechanism.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 illustrates in exploded perspective form the medicine storage and reminder system 10 . System 10 basically includes a container 12 for dry medicines such as pills, capsules, etc., a timer and alarm container 14 and an optional pill splitter 16 .
Medicine storage box 12 basically comprises a plurality of cavities 18 for receiving pills and the like, with a corresponding plurality of hinged lids 20 . Each lid includes an edge 22 which, in a conventional manner, snaps over the corresponding edge of each cavity 18 to releasably hold the lid in the closed position. Any other suitable releasable lid closure means may be used as desired. Any suitable number of cavities and lids may be used. The upper surfaces of lids 20 may bear any suitable indicia such serial numbers, times of day at which medicine is to be taken, days of the week, etc. The lids may be permantly marked or may have a surface suitable for marking with an erasable felt tip marker, a pencil, etc.
Container 12 is releasably secured to timer and alarm container 14 with any suitable releasable fastening means. In the preferred embodiment shown, a plurality of pegs 24 are provided on the back surface 26 of container 12 and a plurality of corresponding holes 28 are provided in the back surface 30 of timer and alarm container 14 . Preferably, four sets of pegs and holes are provided, adjacent to corners of the containers, are preferred. Typically, pegs 24 have enlarged heads that snap into holes 28 in a conventional manner. While any other releasable connection means may be used between container 12 and container 14 , such as hook-and-loop material of the sort available under the Velcro® trademark could be used if desired, the peg and hole arrangement as shown is preferred as providing a particularly effective connection while allowing separation when necessary. A removable cover 36 on back 30 closes a battery compartment in alarm and timer container 14 .
Where at least some conventional compressed pills are to be contained, in many cases a person is required to split the pills and take the halves at different times. Under those circumstances, pill splitter 16 is preferably included. Pill splitter 16 includes a base 34 and a hinged lid 32 movable between an open position as shown to provide access to the interior of base 34 and a closed position covering the base. While any suitable means may be used to releasably secure pill splitter 16 to container 12 , the cooperating tapered slot 38 and wedge 40 arrangement as shown is preferred. Slot 38 conforms to the shape and size of wedge 40 and can be slipped sownwardly over the wedge to be held in place thereon. The shape of the wedge interface prevents pill splitter 16 moving further downwardly, while friction will prevent removal of the pill splitter without significant upward force on the pill splitter.
Pill splitter 16 base 34 includes a shelf 42 having two adjacent upwardly extending walls 46 which are spaced apart in a funnel-like arrngement. A sharp blade 48 is mounted in lid 32 so as to be brought into the space between walls 46 when the lid is closed. Thus, a pill placed between walls 46 , where the space between walls is narrow, will be split by blade 48 when lid 32 is closed. A cavity 50 is provided in base 34 adjacent to the wide end of the funnel formed by walls 46 . After a pill is split, the halves can be moved by a finger tip into cavity 50 . Then additional pills may be split and one half placed in each of cavities 18 in pill container 12 .
A latch mechanism is provided to securely, but easily releasable, hold lid 32 in the closed position while the assembly 10 is carried in a pocket, purse or the like, to prevent inadvertent contact of a finger or other object with blade 48 . The latch mechanism includes a hinged flap 52 mounted on lid 32 having two upstanding end pegs 54 . Two holes 56 are provided in base and positioned so that when lid 32 is closed and flap 52 is moved toward front wall pegs 54 will enter holes 56 and be frictionally locked therein. No outside forces, such as an attmept to raise lid 32 or a bump against the lid will act to unlock flap 52 . To open the flap requires that a fingernail or the like be inserted under the free end of flap 52 and the flap be pulled outwardly. This opening step can only be taken deliberatly, so that inadvertent opening is prevented.
FIG. 2 shows the operating face of timer and alarm container 14 . Container 14 contains conventional batteries, a speaker and a conventional microprocessor (not shown) for operating the system shown in block diagram in FIG. 8 . Any suitable microprocessor may be used. A preferred microprocessor is the KS57C2504 microcontroller available from the Samsung Electronics company. The microprocessor is programmed in a conventional manner to perform the operations described below.
Face 58 of container 14 includes a liquid crystal display 60 which normally displays the time on a twelve-hour basis, plus an AM/PM indication. A “broken battery” symbol 61 will appear when the battery is depleted and only a few weeks of service remain. Display 60 will also display information ast when each alarm's last dose was taken, the “next” programmed time, the number of doses taken, missed and intentionally skipped and when a time is a “scheduled” time. Openings 62 , typically slots or small spaced round openings are provided for emission of sound from the conventional internal speaker (not shown). A series of light emitting diodes is provided, corresponding in number to the number of capsules 18 provided in pill container 12 . Indicia, typically numbers or other markings corresponding to markings on lids 20 are preferably provided adjacent to LED's 64
A series of switch buttons 66 is provided for operation of the system. The multiple functions of these buttons 66 will be explained in the description of system operation, below, in conjunction with the showing in FIG. 3 .
A hinged lid 68 is movable between an open position giving access to all button switches 66 and a closed position covering all but the button labeled “medicine taken” to protect the covered button switches. Latch tab 70 on lid 68 snaps over edge 72 on surface 58 of container 14 to releasably hold the lid closed, as best seen in FIG. 3 . Tabs 74 (as best seen in FIG. 1) extend from lid 68 for engagement by fingers to open the lid. Pill container 12 and timer and alarm container 14 are preferably formed from a tough, flexible plastic such as acrylonitrile-butadiene-styrene (ABS).
FIG. 3 shows the timer and alarm container 14 in plan view, with preferred labels on the switch buttons 66 indicating functions in the different operational modes. Light emitting diodes have adjacent numbers corresponding to the cavities 18 as seen in FIG. 1 .
The arrangement of the electronic components is schematically illustrated in the block diagram of FIG. 4 . Microprocessor 106 , typically the KS57C2504 microcontroller mentioned above is powered by a battery pack 108 , typically two 1.5 volt AA batteries. A battery low indicator 110 warns that the batteries will run out shortly. Typically, indicia 61 is displayed on display 60 (as seen in FIG. 3) when batteries are low.
Microprocessor 106 is controlled by button switches as indicated in block 112 . Typically these are conventional pressure sensitive switches as shown at 66 in FIG. 3 . Microprocessor 106 drives a display 114 , typically a liquid crystal display 60 as seen in FIG. 3, and alarms such as lights 116 and speaker 118 . Replaceable pressure sensitive labels may be provided on the lid 68 so that information about the pills contained in each compartment can be written thereon. Or, the surface may be such that the information can be written directly on the lid in pencil or erasable pen and erased and rewritten as needed.
General System Operation
Device 10 may be operated in any suitable manner. Preferably, three operating modes are provided, generally termed the “normal mode”, the “program mode” and the “alarm mode”. There are three main modes in the Easy Minder: Normal Mode, Program Mode and Alarm Mode. During Normal Mode the device is simply showing the time of day. During Program Mode the device is ready to accept programming data from the user. In this mode the display and/or one of the LED's will flash indicating that it is in program mode. During Alarm Mode the device will indicate the scheduled time and the next scheduled time for each alarm that has gone off. The alarm will beep to alert the user that a scheduled time has arrived. The LED's will blink indicating which alarm(s) is active.
The functions of all the buttons of the Medicine Reminder in all the three modes ar as follows:
The following are brief descriptions of the various modes of the Medicine Dispenser With Detachable Timing Device of the present invention.
Normal Mode
SET CLOCK
To set the time of day
SELECT ALARM
To choose one of the six alarms and put the device in Program mode
CLEAR ALARM
No function
REVIEW SCHEDULE
To show the schedule programmed for all of the alarms
HOUR/VOLUME+
To increase the speaker volume
MINUTE/VOLUME
To decrease the speaker volume
SAVE/LAST TAKEN
To request the device to display the time last taken of all the programmed alarms
DONE/MEDICINE TAKEN
No function
Program Mode
SET CLOCK
To find out how many medicines the user has taken, has forgotten to take, and has intentionally skipped of a particular alarm.
SELECT ALARM
To move to the next alarm
CLEAR ALARM
To clear all previously programmed time for the selected alarm
REVIEW SCHEDULE
To review all previously programmed time for the selected alarm
HOUR/VOLUME+
To increase the Hour in the display
MINUTE/VOLUME
To increase the Minute in the display
SAVE/LAST TAKEN
To save in memory the last entry
DONE/Medicine TAKEN
To get out of program mode
Alarm Mode
SET CLOCK
No function
SELECT ALARM
No function
CLEAR ALARM
When the user hits this button in Alarm mode, the device will stop displaying the scheduled time and the next scheduled time for the lowest numbered (ex. Alarm # 1 ) active alarm. The device will increment the counter to total the number of medicines the user has intentionally not taken for that alarm. The device will stop that alarm from beeping.
The device will continue showing the times for the remaining alarms that are going off, if any. Therefore, the user must hit either Clear Alarm or Done/Medicine Taken once for each alarm that is going off.
REVIEW SCHEDULE
No function
HOUR/VOLUME+
To increase the alarm volume
MINUTE/VOLUME
To decrease the alarm volume
SAVE/LAST TAKEN
To request the device to display the time last taken of all the programmed alarms that are going off and then return to display the scheduled time and the next scheduled time of all the alarms that are going off.
DONE/Medicine TAKEN
To tell the device that the user has taken that medicine. When the user presses this button in Alarm mode, the device will stop displaying the scheduled time and the next scheduled time for the lowest numbered (ex. Alarm # 1 ) active alarm. The device will increment the counter to total the number of medicines taken for that alarm. The device will stop that alarm from beeping. The device will continue showing the times for the remaining alarms that are going off. Therefore, the user must hit either Clear Alarm or Done/Medicine Taken once for each alarm that is going off.
Operation of a Preferred Embodiment
1. Normal Operation:
The display normally shows the time of day (12 hour display with AM/PM indicator) until a scheduled time for an alarm is reached.
2. When the device reaches a scheduled time for an alarm:
a) The alarm will beep for 0.5 second every two seconds over a 30-second period. After the first 30 seconds, every several minutes (typically five minutes), the alarm will beep for 0.5 second, typically every two seconds over a ten second period until, the Done/Medicine Taken button or Clear Alarm button is pressed.
b) The LED corresponding to that alarm will quickly flash. The display alternates between showing the scheduled time for about two seconds together with the word “TAKE” and then display the next scheduled time for another two seconds with the word “NEXT”. The device will perform these operations consecutively until the Done/Medicine Taken or Clear Alarm button is pressed.
3. When the device reaches another scheduled time for the same alarm before the user presses the Done/Medicine Taken or Clear Alarm button for the previously programmed time:
a) The device deletes the previously scheduled time and perform the same operations as in section 2 with the new scheduled time. Therefore, the display flashes the new scheduled time as well as the next scheduled time.
b) When this occurs, the device counts and stores this incidence of a missed medicine (or “non-compliance”).
4. When the device reaches a scheduled time for an alarm while displaying the scheduled time for another alarm(s) not yet acknowledged by the user:
a) The alarm will beep for 0.5 second every two seconds over a 30-second period. After the first 30 seconds, every five minutes, the alarm beeps for 0.5 second every two seconds over a ten second period until the Done/Medicine Taken or Clear Alarm button is pressed. One of these two buttons must be pressed for each alarm that is going off.
b) The device performs the following operations consecutively until the Done/Medicine Taken or Clear Alarm button is pressed. One of these two buttons must be pressed for each alarm that is going off.
The LED corresponding to the first alarm quickly flashes and display shows the scheduled time for about two seconds and then flashes the next scheduled time for about two seconds. The LED for that alarm then goes off. The LED of the next alarm will then quickly flash for two seconds. During these this time, the display flashes the scheduled time for about two seconds and then shows the next scheduled time for about two seconds.
c) The device performs this cycle of operations for each of the alarms that has reached its scheduled time until the Done/Medicine Taken or ClearAlarm button is pressed. One of these two buttons must be pressed for each alarm that is going off.
d) Then the device goes back to step 2 b.
e) The user must hit the Done/Medicine Taken or Clear Alarm button once for each alarm that is active. The device will then erase each active alarm in chronological order. For example, if three different alarms are active (Alarm # 1 , # 3 , and # 5 ), the user hits Done/Medicine Taken or ClearAlarm once and the device will turn off Alarm # 1 . The user will then need to hit Done/Medicine Taken or Clear again to then turn off Alarm # 3 .
The user will then press Done/Medicine or ClearAlarm again to turn off Alarm # 5 . The device will deactivate the alarms in sequential order (# 1 through # 6 ) regardless of which alarm became active first. The device will then display the time of day until another scheduled time is reached.
5. When a scheduled medicine is an elective medicine and it is up to the patient if he or she feels it necessary to take it at the programmed time, the user will have two options. If the user decides to take the medicine at that time, the user presses Done/Medicine Taken. The device will increment the counter that keeps track of the number of times the user chooses to take this alarm's medicine. If the user decides not to take the medicine, the user presses Clear Alarm. The device will increment the counter that keeps track of the number of times the user chooses not to take this alarm's medicine.
6. When the unit is in any of the program modes, the device will return to normal mode if the user does not hit any button within 60 seconds.
Programming the Medicine Reminder
At the press of any key, the device will produce a distinguishable beep sound indicating that a key has been pressed.
To Program Time of Day
1. Press Set Clock. The Clock Display will flash, indicating the device is in program mode.
2. Press the Hour/Volume+ and Minute/Volume,− buttons until the correct time of day shows on the display.
3. Press Save/Last Taken.
4. Press Done/Medicine Taken. The Clock Display will display current time of day.
To Program One Alarm
1. Continue pressing Select Alarm until the LED of the alarm to be programmed quickly flashes. The clock display will slowly flash, indicating the device is in Program mode. If there is nothing programmed for this alarm, the clock display will flash (0:00, OFF or Blank.) If there is a time programmed for this alarm, the display will flash the first time of day for which that alarm has been previously programmed.
2. If the display shows (0:00, OFF or Blank), perform steps 2.1 to 2.3. Otherwise perform steps 3.1 to 3.5. Simply press Hour/Volume+ or Minute/Volume− buttons until the first required schedule time shows on the display.
2.2 Then press Save/Last Taken. Continue repeating steps2.1 to 2.2 until all times for that alarm have been entered.
2.3 Press Done/Medicine Taken. The LED corresponding to the alarm being programmed and the clock display will stop flashing. The display clock will return to time of day.
3. If the clock display shows any time, perform steps 3.1 to 3.5.
3.1 Press Clear Alarm to erase all previously programmed times for this alarm. The display will show 0:00, OFF or be blank.
3.2 Press the Hour/Volume+, and Minute/Volume− buttons until the required schedule time shows on the display.
3.3 Then press Save/Last Taken.
3.4 Continue steps 3.2 and 3.3 until all times for that alarm have been entered.
3.5 Press Done/Medicine Taken. The LED corresponding to the alarm being programmed and the clock display will stop flashing. The display clock returns to the time of day.
4. If Done/Medicine Taken is not pressed after 60 seconds, the device goes back to normal operation.
5. To correct a mistake while programming, press Done before pressing Save. Entries programmed are not saved until Save is pressed.
To Review Alarm Program
There are two options to review the times for which each alarm has been programmed:
Option 1
In Normal mode, press the Review Schedule button. The device will light LED # 1 and show all the times programmed for that medicine for about two seconds each. Also, “SCH” will appear on the display indicating that these are scheduled times. The device will then perform this function for all the alarms which have been programmed previously. The device will continue scrolling all the times for which each of the alarms have been programmed until each alarm's schedule is displayed a total of three times. If Done/Medicine Taken is pressed during the time the display is displaying the schedules, the device goes back to normal operation.
Option 2
In Program mode, press Select Alarm until the LED of the alarm corresponding to the alarm that the user wants to review goes on. The display will flash the first programmed time and display “SCH”. Press Review Schedule. The device will show all the times programmed for that alarm. The display will flash each programmed time for about two seconds. The display will continue scrolling through all scheduled times until each alarm's schedule is displayed a total of three times. If Done/Medicine Taken is pressed, during the time the display is displaying the schedules the device goes back to normal operation.
To Clear an Alarm Completely
1. Press Select Alarm until the LED of the alarm corresponding to the alarm that the user wants to clear goes On. The LED corresponding to that alarm and the clock display will flash the first programmed time indicating the device is in Program mode.
2. Press Clear Alarm. The display will flash (0:00, OFF or Blank) indicating there are no programmed times for that alarm and that the unit is ready to be programmed. This operation completely clears all the times for which that alarm has been programmed and will not beep any longer until the user re-programs that alarm. The “missed”, “taken” and “skipped” compliance counters for that alarm are also cleared and reset to “0”.
3. Press Save/Last Taken. If Save/Last Taken is not pressed, the alarm will restore to the previous settings when Done/Medicine Taken is pressed.
4. Repeat steps 1 through 3 until all the alarms the user wants to clear have been cleared.
5. Press the Done/Medicine Taken. If Done/Medicine Taken is not pressed, after 60 seconds the device will go back to normal operation.
To Clear a Scheduled Time That has Been Programmed on One Alarm
1. Press the Select Alarm button until the LED corresponding to the alarm which the user wants to turn off time flashes. The display will flash the first programmed time.
2. If the time the user wants to delete shows on the display, perform step 3; if not, perform steps 4 and 5.
3. Simply press the Hour/Volume,+ button until the display shows (0:00, OFF or Blank).
4. Continue pressing Save/Last Taken until the schedule time to be turned off shows on the display.
5. Simply press the Hour/Volume+ button until the display shows (0:00, OFF or Blank). Then press Save/Last Taken again. If the user does not press Save/Last Taken, the alarm schedule will remain unchanged.
6. If the user wants to delete other previously programmed times, the user simply repeats steps 4 and 5 until all the preprogrammed times to be turned off have been turned off.
7. When done press the Done/Medicine Taken button. If Done/Medicine Taken is not pressed after 60 seconds, the device will go back to normal operation.
To Change a Scheduled Time That has Been Programmed on One Alarm
1. Press the select Alarm button until the LED corresponding to the Alarm in which you want to make a change lights up.
2. If the time you want to change shows on the display, perform step 3; if not, perform steps 4 and 5.
3. Simply press the Hour/Volume+ button until the display shows the new required time in hours. Then press the Minute/Volume+ or − button until the display shows the new required time in minutes.
4. Continue pressing Save/Last Taken until the schedule time you want to change shows on the display.
5. Simply press the Hour/Volume+ or = button until the display shows the new required time in hours. Then press the Minute/Volume+ or − button until the display shows the new required time in minutes.
6. If the user wants to change a previously programmed time, the user simply repeats steps 4 and 5 until all preprogrammed times to be changed have been changed.
7. When done, press the Done/Medicine Taken button. If Done/Medicine Taken is not pressed, after 60 seconds the device will go back to normal operation.
To Adjust the Alarm Volume
1. Whenever the device is not in program mode (Set Clock, Select Alarm or Review Program buttons have not been pressed, the Hour/Volume+ and Minute/Volume− buttons will serve as volume controls for the alarm. Whenever the Hour button is pressed in non-programming mode, the alarm will beep, indicating the new higher volume.
2. Whenever the Minute/Volume− button is pressed in non-programming mode, the alarm will beep, indicating the new lower volume.
3. The alarm preferably has six different volume levels.
To Review the Record of Medicine Doses Taken
This includes doses the user has not taken, forgotten to take and/or intentionally did not take for each medicine.
1. In Normal mode, continue pressing Select Alarm until the LED of the alarm corresponding to the medicine that the user wants to review flashes.
2. Press Set Clock once. The display will show the number of doses of this medicine taken by displaying “TAKEN” and how many doses of this medicine the user has taken since the last time the unit was cleared. The display will show this information for about two seconds, then the display will show the number of dosed of this medicine has forgotten to take by displaying “MISSED” and how many doses of this medicine the user missed since the last time the unit was cleared. The display will show this information for about two seconds. Then the display will show the number of doses the user intentionally did not take by displaying “SKIPPED” and the number of doses the user skipped or did not take. The display will show this information for about two seconds.
3. Press Clear Alarm while this information is being displayed to erase/reset counter. The information in all three counters will be reset. Then press Save/Last Taken. If the user does not press Save/Last Taken, then the counter and the programmed schedule will not be reset.
4. If no button is pressed, after the display shows the entire sequence of “TAKEN”, “MISSED” and “SKIPPED” for a total of three times the device will return to the normal mode.
To Review the Last Time a Specific Medicine was Taken
There are three options to review last time the user took each medicine.
Option 1
In Normal mode, press the Save/Last Taken button. The device will light LED # 1 and show “LAST” for two seconds the last time medicine # 1 was taken. The device will then perform this function for all the alarms which have been programmed. The device will continue scrolling all the times of the last medicine taken until the user presses Done/Medicine Taken. If Done/Medicine Taken is not pressed, the device goes back to normal operation after the display shows the sequence for a total of three times.
Option 2
In Program mode, continue pressing Select Alarm until the LED corresponding to the medicine flashes. The display will flash the first programmed time for that alarm. Press Save/Last Taken. The device will show the last time that medicine was taken. The display will continue showing the last time the user took that medicine until the user presses Done/Medicine Taken to return to Normal mode. If Done/Medicine Taken is not pressed, after 30 seconds the device goes back to normal operation.
Option 3
In Alarm mode, if the alarm has reached a programmed time and is flashing the current programmed time and the next programmed time, press Save/Last Taken to view the last time medicine was taken for that alarm. The device will display the last time that medicine was taken for three seconds and the alarm's corresponding LED will flash, and then return to the previous mode to show the scheduled time and the next scheduled time of the alarm.
If there is more that one alarm going off at the same time the display will show for three seconds the last time the medicine was taken for each alarm while also flashing the corresponding LED.
Where it is desired that a pill be split in two to reduce the dose by half, pill splitter 16 is opened, the pill is placed between walls 46 at the narrow end and the cover is closed, causing blade 48 to safely divide the pill. The two halves can be pushed into cavity 50 and additional pills split.
Other variations, applications and ramifications of the invention will be understood upon reading this disclosure. Those are intended to be included within the scope of this invention, as defined in the appended claims. | An electronic device for holding medicines, typically pills, to be taken at different times and to remind the user to take particular pills at specific times. A first container has a plurality of pill holding compartments, with a hinged lid closing each compartment. A second container, which is releasably fastenable to the first compartment, contains a microprocessor, an alarm, a display and buttons for controlling the microprocessor to display different information. The display can be set to show the time, times for taking pills from different compartments, whether pills have been taken on time, if a pill has been missed or skipped, when the last pill has been taken, etc. When a time set for taking a pill arrives, an alarm, typically a light and/or sound alarm, alerts the user as to the compartment holding the pill to be taken. A pill splitter is further provided that can be releasably fastened to one of the compartments and provides quick, accurate and safe splitting of pills so that halves may be placed in the compartments to be taken as indicated by the alarm system. | 0 |
FIELD OF THE INVENTION
The invention relates to hinges. It is particularly, but not exclusively, related to hinges used in electronic devices. In one embodiment, it relates to hinges used in portable electronic devices.
BACKGROUND OF THE INVENTION
Many types of electronic devices are known. Portable electronic devices include mobile telephones, personal digital assistants (PDAs) and portable computers such as laptops. As technology improves, it is desired to include more functions in such devices. These functions may include messaging, for example e-mails and SMS (short message service), and entry of various types of information which are useful for a user to be able to access, such as address and calendar information. To provide access to these functions, the devices often comprise user interfaces such as displays and full alphanumeric keyboards or touch-sensitive screens.
It may not be necessary for the complete user interface to be available all of the time. Therefore, some of these devices are foldable so that at least part of the user interface can be stored away when it is not required. In the case of a laptop, it is typically provided in a two-part form connected by hinges having a display in one part and a keyboard in another part. In the case of a multi-function device such as a combined mobile telephone/PDA, there are occasions when a full alpha-numeric keyboard is needed, for example when composing messages or editing text, and other occasions when it is not needed, for example when it is being used as a telephone. An example of such a device is the Nokia® 9110 Communicator.
FIG. 1 shows a prior art mobile device 10 . The mobile device 10 comprises a body part 12 and a cover part 14 which are moveable between a configuration in which the mobile device is open (unfolded) and a configuration in which the mobile device is closed (folded). The body part 12 and the cover part 14 are connected by a pair of hinges 16 . The body part 12 comprises necessary control electronics to enable the mobile device 10 to carry out telephony and PDA functions and, on an inner surface which faces the cover part 14 when the mobile device 10 is closed, a full keyboard. The keyboard is used in operation of the mobile device 10 as a PDA and in other operations. The cover part 14 comprises a conventional telephone interface on an outer surface and, on an inner surface which faces the body part 12 when the mobile device 10 is closed, a display. The cover part also comprises an antenna for transmission and reception of radio signals.
Since these devices are usually opened to present a user interface to a user, it is convenient if they can be held open at one or more particular angular configurations. To provide this ability, hinges are used having a suitable stiffness to resist rotation. It is difficult to maintain this ability after thousands or even tens of thousands of openings since wear tends to reduce the stiffness. Although it is possible to provide additional locking means to hold the device in any desired angular configuration (including locking the device in a closed configuration), having such locking means requires additional parts which results in additional weight and space. This is often not desirable since these devices are typically portable and should be lightweight and compact.
The hinge 16 used in the device 10 is shown in FIG. 2 . The hinge 16 comprises a first hinge pin element 220 attached to the body part 12 and a second hinge pin element 221 attached to the cover part 14 . The hinge pin elements are fixed against rotational movement relative to their respective parts. The first hinge pin element 220 and part of the second hinge pin element 221 are contained in a common hinge pin housing (not shown). An end 222 of the first hinge pin element 220 is provided with a tab 223 and an end 224 of the second hinge pin element 221 is provided with a slot 225 . The hinge pin elements abut at their respective ends so that the tab 223 is received in the slot 225 . The first hinge pin element 220 is spring-biased by a spring 226 so that the tab 223 is pressed into the slot 225 . This keeps the body part 12 and the cover part 14 held relatively to each other.
When the cover part 14 and the body part 12 are moved about the hinge 16 relatively to each other, the tab 223 is forced out of the slot 225 , the first hinge pin element 220 moves against its spring-biasing and the hinge pin elements rotate relatively to each other.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a hinge comprising a shaft part and a housing part, the parts being relatively moveable about a common axis of rotation, the shaft part having a first portion lying on the common axis of rotation, the first portion carrying a bearing surface, and a second portion extending radially beyond the bearing surface of the first portion, the housing part having an engagement surface and a hinge surface, the hinge surface cooperating with the bearing surface of the first portion and the engagement surface engaging with the second portion to restrain the shaft part from rotational movement, the shaft part being moveable relative to the housing part between a first position in which the second portion is engaged with the engagement surface and a second position in which the second portion is not engaged with the engagement surface.
In a hinge according to the invention, it is not necessary to provide separate parts, such as a latch, to provide a locking function since this is provide by the interrelation between the shaft part and the housing part. Therefore, the hinge can be provided in a miniature form relatively straightforwardly.
Preferably the bearing surface is spaced apart from the common axis of rotation in radial directions. Preferably different parts of the bearing surface are spaced from the common axis of rotation by the same distance. In this case, the first portion has a round cross-section.
Preferably the second portion extends laterally with respect to the common axis of rotation.
Preferably the hinge surface encloses the first portion. Preferably the hinge surface does not enclose the second portion. Preferably the hinge surface does not enclose the engagement surface.
Preferably, in the second position, the shaft part is not restrained from rotational movement. Preferably in this position the first portion is acted upon by a biasing force in a first direction parallel to the common axis of rotation. Preferably in moving from the first position to the second position, the second portion is displaced axially in a second direction opposite to the first direction.
Preferably the first portion and the second portion meet at a junction and are disposed in an angular relationship. Most preferably, they are disposed at right angles to each other. This disposition may not be exactly equal to 90°. It may be slightly more or slightly less. It may vary as the shaft part and the housing part move relatively to each other. In another embodiment, the first portion and the second portion meet at an acute or an obtuse angle. Preferably the first and second portions are integrally formed. They may comprise a bent wire. A wire can be bent easily to fit into small hinges. Clearly, this is also inexpensive.
Preferably the shaft part comprises spring biasing means to provide the biasing force. Preferably the biasing force is provided by energy stored when the first and second portions are moved relatively to each other. Preferably the hinge surface does not enclose the spring biasing means.
Preferably the shaft part comprises a pair of first portions. Preferably the shaft part comprises a pair of second portions. The second portions may be substantially parallel. Preferably the second portions are connected together by a connecting portion. Preferably the first portions extend from the second portions away from each other. Alternatively the first portions extend from the second portions towards each other. The second portions may lie on the same axis. They may both lie on the common axis of rotation.
Preferably the housing part comprises a pair of hinge surfaces. Each of the hinge surfaces may co-operate with the bearing surfaces of the pair of the first portions.
Each hinge surface may be associated with a pair of engagement surfaces. This pair of engagement surfaces may be provided to restrain the second portion at two separate angular orientations of the shaft. The angular orientations may be separated by an angular separation of 120°. Alternatively, the angular separation may be another value such as 90° or 180°. Each hinge surface may be associated with more than two engagement surfaces to provide more than two restraining angular orientations.
Preferably the or each engagement surface has a profile which is complementary to that of a least a part of the bearing surface of the first portion which it restrains. Alternatively, the profile is not complementary so that there is limited contact between the or each engagement surface and the first portion. The or each engagement surface may be provided by a groove having a pair of walls and a bottom. The or each engagement surface may comprise a wall of the groove. In this embodiment, restraining of the shaft part occurs by the first portion being pressed into the groove by the biasing force. In order for the shaft part to move rotationally, the first portion needs to move out of the groove. The depth of the groove may determine the amount of restraining force provided by engagement between the engagement surface and the first portion. A deeper groove may provide a greater restraining force. The angle of the groove wall may determine the amount of restraining force provided to the first portion. The restraining force may be determined by factors such as the length or the thickness of the second portion.
According to a second aspect of the invention there is provided an electronic device comprising a first body element and a second body element connected by a hinge according to the first aspect of the invention.
The hinge may enable the body elements to move relatively to each other so that the device may be opened and closed. Preferably the shaft part is fixed to one body element and the housing part is fixed to another body element.
Preferably the device is portable. Preferably the device is selected from a group consisting of a mobile station, a mobile telephone, a mobile communicator, a personal digital assistant or a mobile computer such as a laptop.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will be described with reference to the accompanying drawings in which:
FIG. 1 shows a mobile device according to the prior art;
FIG. 2 shows a hinge prior according to the prior art;
FIG. 3 shows a hinge according to the invention in a disassembled state;
FIG. 4 shows the assembled hinge in a closed position;
FIG. 5 shows the assembled hinge in an open position;
FIGS. 6 a to 6 d show different hinge configurations;
FIGS. 7 a and 7 b show details of different hinge embodiments;
FIGS. 8 a and 8 b show details of different hinge embodiments;
FIGS. 9 a and 9 b show details of different hinge embodiments;
FIG. 10 shows detail of another hinge embodiment; and
FIG. 11 shows yet another hinge embodiment; and
FIG. 12 shows still yet another hinge embodiment.
DETAILED DESCRIPTION
FIG. 3 shows a hinge 16 according to the invention. It is shown in a disassembled state in order to present its features and its construction clearly. The hinge 16 is to be used in a mobile device according to FIG. 1 described above. The hinge 16 comprises an elongate hinge housing 20 and a co-operating hinge shaft element 22 . The hinge shaft element 22 is generally U-shaped having two parallel legs 24 . The legs 24 are connected at one end by a curved portion 26 . Located at the other end of the legs 24 are oppositely extending hinge shafts 28 .
The hinge housing 20 comprises polymeric material, such as an injection moulded plastic. The material is hard-wearing enough to resist wear caused by movement of the hinge shaft element 22 .
The hinge shaft element 22 is formed out of a single piece of metal wire which is bent into shape. Spring steel wire is suitable. Once it has been formed, the hinge shaft element 22 can be elastically deformed by pushing the hinge shafts 28 towards each other. In effect, the hinge shaft element 22 is a spring. The hinge shafts 28 co-operate with the hinge housing 20 . The hinge housing 20 comprises an entry part 30 into which the hinge shaft element 22 is inserted and a pair of bore holes 30 for receiving each of the hinge shafts 28 . The boreholes 32 are located at opposite ends of the hinge housing 20 . Each bore hole 32 is associated with a contact surface 34 over which ends of the legs 24 ride as the hinge shaft element 22 moves in relation to the hinge housing 20 . The contact surfaces 34 each comprise a pair of grooves 36 and 38 separated by a flat surface 40 . The entry part 30 is provided with a pair of sloping faces 42 and 44 which help in locating the hinge shafts 28 in the bore holes 32 as will be described below.
On assembly, the hinge shaft element 22 is pushed, curved portion 26 first, into the entry part 30 . The hinge shafts 28 engage the sloping faces 42 and 44 and they are pushed closer together as the hinge shaft element 22 is pushed further into the entry part 30 . When the hinge shafts 28 reach a position level with the bore holes 32 , elastic energy stored by the hinge shaft element 22 pushes the hinge shafts 28 into place in the bore holes 32 and the hinge shaft element 22 snaps into place. It may be preferred for the hinge shaft element 22 to have a relaxed, undeformed, state in which it is wider at the ends of its legs 24 than the separation of corresponding opposing pairs of grooves. In this case, when the hinge shaft element 22 is snapped into place and the ends of the legs 24 are located in the grooves, elastic energy remains stored in the hinge shaft element 22 resulting in a biasing force being applied to the hinge shafts 28 .
Once assembled the hinge can move between two locked configurations as shown in FIGS. 4 and 5. In moving, the hinge shaft element 22 moves about a common axis of rotation which runs through the boreholes 32 and through the hinge shafts 28 .
FIG. 4 shows the assembled hinge 16 in a closed position in which the legs 24 are received and held in the grooves 36 . The hinge housing 20 is fixed to the body part 12 of the mobile station and the curved portion 26 is fixed to the cover part 14 . The body part 12 is not shown. Only part of the cover part 14 is shown. It can be seen that the curved portion 26 is located in a slot which extends around a former. A hole located in the former can receive a screw with is used to mount the hinge 16 onto the cover part 14 .
FIG. 5 shows the assembled hinge 16 in an open position in which the legs 24 are received and held in the grooves 38 .
In moving the hinge 16 from the closed position to the open position, force is applied to the hinge shaft element 22 to move it about the common axis of rotation. This forces the ends of the legs 24 located in the grooves 36 to ride up side walls of the grooves 36 so that the hinge shafts 28 are pushed closer together against the biasing force which acts along the common axis of rotation. As the hinge shaft element 22 is moved, the ends of the legs 24 come completely out of the grooves 36 so that they rest on the flat surfaces 40 . This increases the biasing force applied to the hinge shafts 28 . The legs 24 then ride across the flat surface 40 until, in their progress, they arrive at the location of the grooves 38 and are pushed into them.
It may be preferred for the hinge shaft element 22 to have a relaxed, undeformed, state in which it is as wide at the ends of its legs 24 as the separation of corresponding opposing pairs of grooves. In this case, there is no biasing force when the ends of the legs 24 are located in the grooves. However, it is still desirable for a biasing force to be applied when the ends of the legs 24 rest on the flat surfaces 40 in order that the ends of the legs be pushed into the grooves 36 and 38 .
It can be understood that a certain amount of force is required to cause the ends of the legs 24 out of the grooves 36 and 38 . Accordingly, the engagement of the ends of the legs 24 with the grooves 36 and 38 creates a locking force which serves to hold the hinge shaft element 22 in a particular orientation and thus likewise hold the body part 12 and the cover part 14 in a particular orientation.
To assist in understanding the preceding description, FIGS. 6 a to 6 d show part of a different hinge embodiment having a plurality of hinge configurations. The principles involved in operation of this hinge embodiment are the same as those involved in operation of the hinge embodiment previously described. The hinge embodiment of FIGS. 6 a to 6 d comprises a hinge housing 60 and a hinge shaft 62 carried by a leg 64 . The hinge shaft 62 locates in a borehole 66 . Grooves 67 and 68 are located on opposite sides of the borehole 66 corresponding to the hinge shaft 62 occupying rotational orientations separated by 180°. The grooves 67 and 68 are separated by a flat surface 69 . As can be seen, the hinge housing 60 is presented only in a fragmentary view which shows its significant features.
FIG. 6 a shows the hinge shaft 62 being inserted into the borehole 66 . FIG. 6 b shows a first locking position in which the end of the leg 64 is located in the groove 67 . In common with the previous description, it is held in place by a biasing force. FIG. 6 c shows the leg 64 moving from the first locking position. A turning force applied to the leg 64 forces its end to come out of the groove 67 and the hinge shaft 62 to move relatively to the hinge housing 60 in a direction opposite to the biasing force. Once the leg 64 is free of the groove 67 , its end can move across the flat surface 69 . The biasing force increases the limiting friction between the end of the leg 64 and the flat surface 69 and so enables the leg 64 to be held relatively to the hinge housing 60 in an intermediate position between grooves. In this way, intermediate locking positions are possible although in these positions the leg 64 is not as firmly locked as the locking positions provided by co-operation between the leg 64 and the grooves 67 and 68 . The end of the leg 64 completes its progression across the flat surface 69 and its end is pushed into groove 68 by the biasing force.
These Figures show an arrangement in which locking positions have an angular separation by 180°. The grooves can be located so that the locking positions have other angular separations. In addition, the hinge housing 60 may have more than two grooves in order to provide more than two locking positions.
FIGS. 7 a and 7 b and FIGS. 8 a and 8 b show details of groove profiles P 1 , P 2 , P 3 , P 4 which can be used in any of the grooves 36 , 38 , 67 , 68 of different hinge embodiments shown in FIGS. 3-5, and 6 a - 6 d . The principles shown in the Figures can apply to any of the embodiments of the invention previously described. In FIGS. 7 a and 7 b , grooves are shown which have different depths. Deeper grooves provide a greater locking force since a leg of the hinge shaft element located in the groove has to move a further distance against the biasing force in order for the hinge shaft element to be free for rotational movement. In FIGS. 8 a and 8 b , groove profiles P 3 , P 4 are shown which have different wall angles 80 and 82 . The wall angle 80 provides a smaller locking force than the wall angle 82 since if the same force is applied to rotate a hinge shaft element in each case, in the case of profile P 3 in the FIG. 8 a embodiment, a greater proportion of this force is available to force the leg of the grove due to the wall angle 80 .
FIGS. 9 a and 9 b show detail of hinge shaft elements 90 a and 90 b which can be used in different hinge embodiments. These are of the same basic configuration as the hinge shaft elements described in relation to FIGS. 3 to 5 being generally U-shaped having parallel legs 92 a and 92 b connected by curved portions 94 a and 94 b . Located at the ends of the legs are oppositely extending hinge shafts 96 a and 96 b . The legs 92 a are longer than the legs 92 b . Since it is preferred to mount the curved portions 94 a and 94 b of each hinge shaft element 90 a and 90 b in a slot extending around a former as shown in FIG. 4, the curved portions are constrained against changing their shapes in order to allow the legs 92 a and 92 b to be moved towards each other. Accordingly, such movement of the legs 92 a and 92 b occurs by elastic deformation of the legs 92 a and 92 b themselves. The shorter the legs are, the greater amount of force is required to provide such movement and the higher the locking force is.
The locking force can also be varied by using different thicknesses of wire to form the hinge shaft element.
FIG. 10 shows detail of a groove used in another hinge embodiment. The groove 100 has a pair of walls 102 and 104 and a bottom 109 . Adjacent to the wall 102 is a flat surface 106 . At the junction of groove wall 102 and the flat surface 106 , a curved or rounded edge 107 is provided to reduce excessive wear or breakage. The walls 102 and 104 taper relatively to each other so that they become closer as they extend into the groove. The effect of this is to prevent a hinge shaft 108 from being able to rest at the bottom 109 of the groove 100 and instead being gripped by contact with both of the walls 102 and 104 . If there are no gaps between the hinge shaft 108 and the walls 102 and 104 , looseness between the body part and the cover part is eliminated, that is the shaft 108 cannot “jiggle” in the groove 100 . Thus, a gap is left between the hinge shaft 108 and the bottom 109 . The cooperation between the shaft and the taper angle of the walls 102 and 104 may also provide a locking force. The smaller is the taper angle, the greater is the locking force.
FIG. 11 shows yet another hinge embodiment. The hinge 110 comprises a hinge housing 111 and a hinge shaft element 112 . In this case the hinge shaft element 112 has legs 113 carrying hinge shafts 114 which face and extend towards each other. In FIG. 11, the legs 113 are shown located in grooves 115 and 116 . End faces of the hinge housing 111 provide flat surfaces 117 and 118 over which ends of the legs can ride. In this embodiment, when the ends of the legs 113 come out of the grooves, 115 and 116 , the legs 113 are opened so that the hinge shafts 115 are moved away from each other.
FIG. 12 shows still yet another hinge embodiment. The hinge 120 comprises a hinge housing 121 and a hinge shaft element 122 . The hinge housing 121 is fixed relatively to the body part and the hinge shaft element is fixed relatively to the cover part. The hinge shaft element 122 terminates in a locking loop 123 a first leg 124 of which moves in a slot 125 and a second leg 126 of which engages with a groove 127 . An end face of the hinge housing 121 provides a flat surface 128 over which the second leg 126 can ride when it comes out of the groove 127 . The hinge housing 121 comprises two half pieces 129 a and 129 b to allow the hinge 120 to be assembled.
Particular implementations and embodiments of the invention have been described. It is clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented above, but that it can be implemented in other embodiments using equivalent means without deviating from the characteristics of the invention. The scope of the invention is only restricted by the attached patent claims. | A portable electronic device ( 10 ) such as a mobile phone comprises two body parts ( 12, 14 ) moveably connected by hinges ( 16 ). Each hinge comprises a shaft part ( 22 ) and a housing part ( 20 ), the parts being relatively moveable about a common axis of rotation. The shaft part has a shaft pin ( 28 ) lying on the common axis of rotation and a leg ( 24 ) extending laterally with respect to the shaft pin. The housing part has an groove ( 36, 38 ) and a bore ( 32 ), the bore co-operating with the shaft pin and the groove engaging with the leg to restrain the shaft part from rotational movement. The shaft part is moveable relative to the housing part between a first position in which the leg is engaged with the groove and a second position in which the leg is not engaged with the groove. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 USC 119 (e) (1) from U.S. Provisional Patent Application, Ser. No. 61/675,153, filed Aug. 15, 2011, for No Mess-Hassle Free Brush, of common inventorship.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX
[0003] Not Applicable
FIELD OF THE INVENTION
[0004] The present invention pertains to the field of pet accessories, and more specifically to the field of pet grooming devices.
BACKGROUND OF THE INVENTION
[0005] Millions of consumers enjoy the companionship and unrequited love afforded by a pet dog or cat. Because dogs and cats are more often considered a member of the family, most owners provide adequate shelter, a healthy diet and a regular routine for grooming their animals. Regularly brushing an animal's coat is an important part of pet ownership. Regular brushing prevents painful matts from occurring and facilitates a smooth and shiny coat. Grooming gives the pet positive human interaction and promotes a strong bond and loyalty to their owners. Brushing an animal's coat helps control shedding. Most animals shed their fur naturally as their coat is replaced with new hair follicles. Many dogs go through a process called blowing the coat, which usually takes place twice per year. The dog's fur is replaced in to accommodate changing seasons and temperatures. Brushing the animal's fur greatly reduces the time it takes for this process to complete. A major drawback associated with brushing one's pet is dealing with the loose fur that blows about while the brushing the coat. The simple act of brushing the animal results in the pet owner and surrounding furnishings being completely covered in stray hairs. Many pet owners resort to brushing their animals outdoors, to spare themselves the messy clean up associated with brushing their animals inside. During the cold winter months and rainy months of spring, brushing a pet outdoors is an uncomfortable and unpleasant task. The prior art has put forth several designs for pet grooming devices.
[0006] U.S. Pat. No. 5,211,131 to Chun A. K. Plyler describes pet grooming device that includes a vacuum system for removing fleas, ticks, loose hair and other debris from a cat or a dog. It is a hand held device with a detachable head comprised of bristles for brushing.
[0007] U.S. Pat. No. 5,074,006 to Nunzio Eremita describes a pet vacuum comb to quickly remove fleas, ticks, loose hair and debris from a pet's coat. The device utilizes a housing unit with spaced apart tines on the front end. The middle and back ends comprise a vacuum system followed by a removable canister to collect the debris.
[0008] U.S. Pat. No. 4,799,460 to Lynn Kuhl describes a light weight, battery operated portable unit designed and utilized as a vacuum cleaner for pets. It is a cylindrically shaped unit with a front end containing a circular brush followed by a middle section housing a vacuum fan and electrical components. An end section contains a battery compartment and a canister for collecting a pet's debris.
[0009] None of these prior art references describe the present invention.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide an improved animal grooming brush specially designed for collecting and containing loose hairs brushed from a pet's shedding coat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of the top side of a first embodiment of the present invention showing soft bristles, holes on the top of the brush and battery storage area in the handle.
[0012] FIG. 2 is a perspective view of the bottom side of the first embodiment shown in FIG. 1 showing the see through hair receptacle.
[0013] FIG. 3 is a perspective view of the top side of the first embodiment shown in FIGS. 1 and 2 showing how the soft bristled brush top detaches from the canister to allow elimination of the collected hair into a trash receptacle.
[0014] FIG. 4 is a side perspective view of an alternative embodiment of the present invention standing on one end, showing a handle on the back side and a brush on the front side.
[0015] FIG. 5 is a perspective back view of the embodiment shown in FIG. 4 standing on one end, showing a canister for holding pet hair and handle for holding the brush.
[0016] FIG. 6 is a perspective front view of the embodiment shown in FIGS. 4 and 5 standing on one end, showing hair suction holes and a battery storage area.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention, a pet grooming device is a grooming brush designed to capture loose fur or hair as it is brushed free from the animal, preventing this loose hair from coating the groomer and their surroundings.
[0018] In a first embodiment of the present invention, the head of the brush is oval in shape with an elongated, ergonomically designed handle attached to the base of the brush head. This first embodiment of the present invention is shown in FIG. 1 . The first embodiment of the present invention, as shown in FIG. 1 , comprises an elongated handle [ 1 ], bristles [ 2 ] and holes [ 3 ] on the top side of the brush head. Loose hair or fur from the animal is pulled through these holes [ 3 ] by a vacuum, not shown, housed in the brush. Still referring to FIG. 1 , a hair reservoir [ 4 ] on the bottom of the brush for containing the loose hair or fur is shown. Further as shown in FIG. 1 , a battery compartment [ 5 ] is housed in the handle. Batteries housed in this compartment powers the small vacuum motor also housed in the handle (not shown).
[0019] FIG. 2 shows the bottom side of the first embodiment of the present invention. The hair reservoir [ 4 ] is on the bottom side of the brush and interlocks with the top side, or in the alternative, is hinged to the top side of the brush to enable the reservoir to be emptied easily. An on/off switch [ 6 ] is also shown on the bottom side of the handle. This switch turns the vacuum motor on and off.
[0020] As shown in FIG. 3 , a plastic covering encompasses the back of the brush head, from which the user empties the reservoir following use. This covering contains an interlocking or comparable fastener.
[0021] FIGS. 4 , 5 and 6 illustrate a second embodiment of the present invention. Referring specifically to FIG. 4 , in this second embodiment the bristles [ 7 ] are attached on a front side of the brush with the handle [ 8 ] being on the opposite back side. As in the first embodiment, holes [ 9 ] are present on the bristle or front side of the brush, as seen in FIG. 6 . As shown in FIG. 5 , the hair is collected in the interior of the brush and a door [ 10 ] serves to allow the user to empty hair. The battery compartment [ 11 ], shown in FIG. 6 , and vacuum motor, not shown, are housed in the base of the brush in this second embodiment. As seen in FIG. 5 , an on/off switch [ 12 ] switches the vacuum on and off.
[0022] The present pet grooming device may be produced in a variety of sizes to fit different animal sizes. Bristles may be either metal tines or fiber bristles. The brush itself may be manufactured primarily of plastic, metal or any other suitable material. An additional consideration for this unit is to contain a rechargeable internally contained battery which can be recharged by plugging the unit into an electrical outlet.
[0023] Using the present pet grooming device is very simple. The user purchases the device in the size and style appropriate for their animal's fur. An Old English Sheep dog may require a large brush with wire tines to brush through its thick coat. A Siamese cat may need a brush with soft bristles for its silky fur. After purchase, the user loads batteries into the battery compartment or charges a rechargeable battery contained within the unit. Grasping the brush in hand, the user activates the unit's vacuum or internal suction mechanism by turning the switch [ 6 ] or [ 11 ] to on. As the user brushes the animal, the device suctions and collects the animal fur into the hair reservoir. After grooming the animal, the user opens the covering which encompasses the collection reservoir and empties the animal fur into any trash receptacle. The user then stores the device until future use.
[0024] This pet grooming device provides pet owners with a simple and sanitary means to groom their pet. Pet owners brush their animals without becoming covered in fur themselves or having the debris settle on to furnishings, carpeting and other household items. Containing this fur and dander prevents pet owners from suffering allergic symptoms such as itchy eyes and runny nose while grooming their pets. Consumers can stay inside to administer this pampering treatment of their pet, facilitating a healthy, shiny coat while also creating a natural bond between the animal and pet owner. The device may be operated easily by adults and children. It may be used by individual pet owners or professional pet groomers or kennel staff. Durably constructed of quality materials, this device may withstand years of repeated use.
[0025] Although this invention has been described with respect to specific embodiments, it is not intended to be limited thereto and various modifications which will become apparent to the person of ordinary skill in the art are intended to fall within the spirit and scope of the invention as described herein taken in conjunction with the accompanying drawings and the appended claims. | A pet grooming device comprising a brush with holes present on the bristle side that collect loose hair or fur. A vacuum motor, housed within the brush pulls the hair or fur through the holes into a reservoir which can be emptied when full. | 0 |
BACKGROUND OF THE INVENTION
This invention relates to brake assemblies more particularly of the type which is used on heavy duty vehicles such as tractor trailors. Conventionally, such brake assemblies are air actuated, there being a cam member which is rotated through a lever arm connected to an air pressure system such as a diaphragm or piston, the cam serving to spread two brake shoes apart to effect the braking action. Such systems are of heavy duty type and normally employ brake shoes each of which has a pair of flanges. These flanges at one end thereof straddle an anchor member and are pivotally connected thereto by means of hardened steel pins which are received in the anchor member and which project therefrom. If the flanges of the brake shoes are provided with holes which receive the anchor pin, the anchor pins must be driven out of or removed from the carrier before the brake shoes can be removed and replaced. This type of arrangement has the advantage that no retaining spring is necessary to maintain the brake shoe flanges in seated relationship on the anchor pins. However, the disadvantage is that the anchor pins must be removed to remove the brake shoes and this is sometimes quite difficult because of dirt, corrosion and the like.
On the other hand, the ends of the brake shoe flanges may be provided simply with semi circular recesses which bear upon the projecting ends of the anchor pins. This arrangement has the advantage that the brake shoes may be removed and replaced without requiring removal of anchor pins but has the disadvantage that retaining springs are required to maintain the flanges in seated relationship upon the anchor pins.
BRIEF SUMMARY OF THE INVENTION
This invention relates to brake shoe assemblies of the type generally discussed above wherein the anchor pins need not be removed to remove and replace the brake shoes but where, also, the arrangement is such that no retaining spring or spring means is required to maintain the brake shoe flanges properly seated upon the projecting ends of the anchor pins.
Briefly stated, the arrangement according to the present invention employs anchor pins whose projecting ends are only part cylindrical and where the corresponding ends of the brake shoe flanges are provided with C-shaped bearing surfaces which, in the operative position of the brake shoes, embrace the projecting ends of the anchor pins through an arc greater than 180° whereby the brake shoes are securely pivotally anchored to the anchor pin, thus obviating the need for retaining springs as mentioned above. On the other hand, the C-shaped bearing surfaces on the brake shoe flanges present mouths having widths greater than a diametrical dimension of the part-cylindrical projecting ends of the anchor pin. Means is provided for retaining the anchor pins in a predetermined angular position relative to the carrier such that only when the brake shoes are swung away from their normal or operative position, the mouth of the C-shaped bearing surfaces is so registered with the anchor pins as to allow withdrawl therefrom without removing the anchor pins from the carrier.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is an elevational view of a brake assembly according to this invention;
FIG. 2 is a view similar to FIG. 1 but showing the manner in which a brake shoe is removed or replaced;
FIG. 3 is a horizontal section taken substantially along the plane of section 3--3 in FIG. 1;
FIG. 4 is an enlarged vertical section taken substantially along the plane of section line 4--4 in FIG. 1; and
FIG. 5 is a view similar to FIG. 4 but showing a modification.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIGS. 1 and 3 in particular, the reference character 10 indicates generally an axle or axle housing assembly which is nonrotatable. It may, for example, be the axle assembly of a tractor trailer vehicle or the like and includes an outer end portion 12 upon which a vehicle wheel and brake drum are rotatably mounted in conventional fashion. A spider or carrier member indicated generally by the reference character 14 is rigidly mounted, as by welding not shown, on the axle or spindle 10 and will be seen to include a boss portion 16 which is centrally apertured snugly to embrace the tapered portion 18 of the axle. The carrier or spider is also provided with diametrically opposed arm portions 18 and 20, the former of which terminates in an enlarged bearing portion 22 and the latter of which terminates in two enlarged anchor pin bosses 24 and 26 as is illustrated best in FIG. 4.
The brake assembly further includes a pair of brake shoes indicated generally by the reference characters 28 and 30, each of which includes a pair of spaced flanges 32 and 34 which are spaced apart to straddle, with slight clearance, the anchor pin bosses 24 and 26 respectively. As will be seen most clearly from FIG. 4, the flanges 32 and 34 of each brake shoe pivotally engage respectively with opposite projecting ends 36 and 38 of the anchor pins indicated generally by the reference characters 40 and 42.
Each pair of flanges 32 and 34 is integrally attached to a corresponding brake shoe table 44 of semicircular shape as is conventional and upon which the brake lining material 46 is attached.
The opposite ends of the flanges 32 and 34 are provided with bearing surface recesses which seat upon the reduced diameter end portions 48 and 50 of the cam rollers 52 and 54, the main bodies 56 and 58 of the cam rollers being straddled by the pairs of flanges and being seated upon the generally S-shaped cam surfaces 60 and 62 of the actuating cam 64. The cam is rigidly affixed to a cam shaft 66 which is journalled in the boss portion 22 and, as is conventional, is provided with an actuating lever extending radially therefrom which is connected to the air operated mechanism of the air brake system.
The pins 68 and 70 pass through and between the pairs of flanges and serve to anchor the opposite ends of the return spring means indicated generally by the reference character 72 which maintains the flange pairs in properly seated relationship upon the reduced end portions 48 and 50 of the rollers 52 and 54 and likewise maintains these rollers in contact with the cam 64.
As so far described, the brake assembly is more or less conventional and further descriptive details thereof should not be necessary. However, according to this invention, the anchor ends of the brake shoe flanges and the anchor pins 40 and 42 are of special construction to provide the improved brake assembly according to this invention.
As will be seen in FIG. 4, each anchor pin includes a cylindrical and enlarged main body portion 74 having a length somewhat less than the width of its anchor pin boss 24 or 26 and is provided with opposite end portions 76 and 78 which project outwardly from the opposite sides of the boss 24 or 26. The anchor pins are retained in fixed position with respect to the bosses 24 or 26 by means of retaining pins 80 and 82, the purpose of which will be presently apparent.
Each projecting end of an anchor pin presents a semi-cylindrical surface 84 as shown in FIG. 2 and because this cylindrical surface does not extend the full 360°, but is instead interrupted by the flat, chordal face 86, a diametrical dimension as indicated at 88 is presented which is less than the diameter of the part cylindrical surface 84, as is illustrated. The ends of the flanges 32 and 34 are provided with C-shaped bearing surfaces 90 which define a mouth slightly larger than the dimension 88 whereby when a brake shoe has been rotated to a particular position with respect to the projecting ends 76 and 78 of an anchor pin, the brake shoe can be withdrawn from its pivotal engagement with the anchor pins, as is illustrated diagrammatically in FIG. 2 by the arrow 92. To provide for this interrelationship of parts, the C-shaped bearing surface 90 extends through an angular arc which is greater than 180°. When the brake shoes are in their operative position, as is shown for the lower shoe 30 in FIG. 2, the C-shaped bearing surfaces 90 are pivotally anchored on and engage the part cylindrical surfaces 84 of the projecting ends of the anchor pins. In this way, the brake shoes can be readily removed and replaced and, at the same time, a retaining spring is not required to force the ends of the brake shoes together to maintain the flange ends in operative seated relationship on the anchor pins.
For disassembling the brake shoe assembly of FIG. 1, normal procedure is to urge for example the brake shoe 30 downwardly to allow the removal of the roller 54, and then to do the same thing with respect to the upper shoe 28, removing the roller 52. At this time, the return spring 72 may be easily removed since the tension thereon has become relaxed and, thereafter, each brake shoe may be rotated about its opposite end with respect to the corresponding anchor pin as is illustrated in FIG. 2 and then withdrawn, when in the proper angular position, as is illustrated. From this, the purpose of the retaining pins 80 and 82 will be seen inasmuch as they are responsible for fixing the anchor pins in such position that the brake shoes can be removed or replaced only when the brake shoes have been swung away from the operative positions thereof as is illustrated in FIG. 1.
FIG. 5 illustrates a modification of the invention and demonstrates that any effective manner of properly orienting the projecting ends 36', 38', 76' and 78' of the anchor pins 40' and 42' may be employed. As in FIG. 4, the central body portions 74' of the anchor pins snugly fit within the conventional bores therefor, but in any case, a different bore size may be employed. Indeed, the anchor pins may be of a uniform diameter throughout their lengths, except of course that the ends have a non-circular shape.
In any event, in FIG. 5 the portions 24' and 26' are slightly narrower than in FIG. 4 or are slotted to receive the retaining plate 89. The retaining plate 89 (there may be two retaining plates, one on each side of the portions 24', 26') is provided with two non-circular bores 91 and 93 conforming to the non-circular ends 36' and 76' of the pins 40' and 42', and so oriented in the plate 89 as to constrain the anchor pins to be oriented as in FIGS. 1 and 2. The construction and operation is otherwise the same as previously described although the embodiment of FIG. 5 does not require the pins 80 and 82 of FIG. 4. | The brake assembly in an air brake system where the brake shoes have double mounting flanges is simplified both as to ease of assembly/disassembly and as to number of conponents by anchoring each brake shoe so that, in operative position, it is fixedly pivoted on an anchor pin but may be pivoted out of operative position around the anchor pin to a position in which it may be disengaged therefrom. | 5 |
This application is a division of my copending application Ser. No. 465,081, filed Apr. 29, 1974, entitled "Well Tool Apparatus and Method", assigned to the same assignee as this application, and which is now U.S. Pat. No. 3,942,373, issued Mar. 9, 1976.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improved means for testing conditions in well bores.
2. Description of Prior Art
Prior art well testing apparatus, as exemplified by U.S. Pat. Nos. 2,686,039; 2,689,920; 2,717,039; 2,814,019; 2,817,808; 2,869,072; 3,004,427; 3,006,186; 3,095,736; and 3,233,170, have been used to locate the freepoint, or location at which pipe or tubing was stuck, in a well bore. Several problems have existed in the prior art, including accuracy of the readings obtained, alignment or placement of the freepoint sensor at a proper null or reference, and those created when a back-off tool was used to loosen the stuck pipe in conjunction with freepoint sensing. Isolation between electrical circuits of the freepoint indicator and back-off tool, necessary from a safety standpoint, was often difficult to maintain. Further, the shock formed when the back-off tool was used to loosen pipe often damaged the relatively sensitive downhole electronic circuits in the freepoint indicator.
Further problems have arisen for those tools when used in recently drilled wells which generally extend to greater depths than prior wells. Heat at these greater depths significantly limited the operation of the electronics used in the well tools, particularly in the freepoint indicators. The increased length of wireline necessary to lower the tools to the greater depths has increased the electrical resistance of the wireline, requiring an increase in the electrical current sent from the surface to insure operation of the backoff tool, thus increasing the voltage drop along the wireline.
SUMMARY OF THE INVENTION
Briefly, the present invention provides a new and improved well tool apparatus and method for sensing and testing conditions in a well bore and for performing certain operations in the well bore.
The present invention includes a magnetic rotor and stator and an intermediate core which form a magnetic circuit whose parameters vary, and thus vary the inductance of a coil, in response to movement of the pipe when stressed, with improved accuracy resulting during operations.
The apparatus and method the present invention further permit backoff and other operations in deeper wells notwithstanding the increased wireline resistance due to the increased depths, by using alternating current which is sent at a reduced current level down the wireline and increased in amplitude to a desired level by a transformer adjacent the backoff tool.
The present invention provides a new and improved apparatus for sensing temperature conditions in a well bore and metal creep and the like in pipe in the well bore due to these temperature conditions, as well as a new and improved inclinometer for sensing the degree of inclination of a well bore.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the apparatus of the present invention;
FIG. 2 is a side view taken partly in section of a transformer subassembly of the apparatus of FIG. 1;
FIG. 3 is a cross-sectional view taken along the lines 3--3 of FIG. 2;
FIG. 4 is a schematic waveform diagram of voltage waveforms present in the apparatus of FIG. 1;
FIG. 5 is a schematic diagram of a temperature sensing apparatus of the present invention; and
FIG. 6. is a schematic diagram of an inclinometer apparatus of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
During drilling and other operations in a well bore B (FIG. 1), a pipe or casing P sometimes becomes stuck as indicated at 10 due to cave-ins and other subsurface earth movements and the like. In the drawings, the letter A (FIG. 1) designates generally the apparatus of the present invention for sensing and testing conditions at various test locations in the well bore B, which includes a surface electronic circuit E and a downhole tool T for use in the well bore B.
The downhole tool T is lowered through the well bore B by an electrically conductive wireline W. The tool T additionally has conventional sinker bars (not shown) mounted therewith in order to furnish additional weight to facilitate movement of the tool T through the pipe P in the well bore B.
The tool T includes a cable head subassembly, or sub, H which electrically connects the wireline W to the remainder of the tool T in the conventional manner. The cable head sub H has a conventional slip join J mounted therebeneath which forms a mechanical and electrical connection between the cable headset H and a conventional casing collar locator L.
An upper bowspring U and a lower bowspring G mount a sensor unit S between spaced upper and lower portions of the drill pipe P in the well bore B. As will be set forth below, and as shown in FIG. 1, when the drill pipe P is stuck at the test location, the sensor S detects that the pipe is so stuck by sensing lack of movement of the pipe P. Alternatively, when the pipe P is free at the test location, relative movement of the drill pipe P when stressed by torque or tension from the surface is transmitted to the sensor means S by the upper bowspring U and lower bowspring G indicating that the drill pipe P is free at the test location. The tool T is moved through the bore B to various locations during testing.
The sensor unit S thus indicates in a manner to be set forth below, the point where the drill pipe is stuck so that a detonator or backoff shot or other conventional backoff apparatus D may be used, as will be set forth, to free the drill pipe P above the stuck point. A transformer sub assembly F transfers power to the detonator D while increasing the electrical current level, so that the power consumption and voltage drop along the wireline W is reduced permitting operation of the detonator D at increased depths for deeper wells, while assuring that proper operating voltage and current levels are presented to the detonator D, as will be set forth.
The surface electronic circuit E includes a detonator control circuit and power supply C, a collar locator indicator circuit I and a sensor monitor circuit M which are selectively electrically connected to the downhole tool T by a multi-position control switch K through a variable resistor 12. The variable resistor 12 is adjusted for impedance matching with the resistance and impedance of the downhole tool T and wireline W.
The detonator control circuit C receives alternating current input power over input conductors 14 and 16 from a suitable alternating current source, such as a generator at the drilling rig or the like. A power supply circuit 18, a conventional voltage regulating direct current power supply, receives the incoming alternating current power from the conductors 14 and 16 and provides positive direct current bias potential at a positive output terminal 18a and negative direct current bias potential at a negative output terminal 18b. The power supply 18 thus provides operating direct current potential for the electronic circuits in the monitor circuit M and the indicator circuit I. The power supply 18 may be of the type providing plural direct current bias levels if the electronic components of the circuit E so require.
A first control switch 20 and a second control switch 22 of the detonator control circuit C electrically connect input alternating current power when closed from the input conductors 14 and 16 to a current reducing transformer 24 so that the detonator D may be energized when the control switch K is in the proper position. It is preferable to use two control switches 20 and 22 in order to prevent inadvertent depression of a single control switch causing operation of the detonator D at an improper time, although it should be understood that only one control switch in the control circuit C may be used, if desired. The current reducing transformer 24 reduces the current received over the input conductors 14 and 16 to a low level, so that the current sent through the control switch K and the wireline W to the detonator D is at a low level and thereby the voltage drop due to the resistance of the wireline W is reduced. The transformer F increases the current level from that received over the wireline W to a sufficiently high level to energize the detonator D.
The monitor circuit M of the surface electronics E includes a conventional operational amplifier oscillator circuit 26 providing output alternating current with a predetermined frequency through a coupling capacitor 28 and a buffer operational amplifier 30 to an isolation transformer 32. The oscillator 26 has an output frequency determined by the phase shift imposed on a portion of its output signal and fed back to its imput terminal through a conventional R-C feedback impedance network 26a.
The buffer amplifier 30 provides an impedance match between the oscillator 26 and the isolation transformer 32 and furnishes the output alternating current signal from the oscillator 26 through a coupling capacitor 30a to the transformer 32 so that the output signal from the oscillator 26 is furnished through the control switch K, when such switch is in the proper position, to the sensor unit S over the wireline W for freepoint sensing operations, to be set forth below. Isolation transformer 32 further prevents direct current offset signals formed in the sensor unit S during freepoint sensing from charging capacitor 30a.
The monitor circuit M further includes an integrator or low pass filter 34 which responds to the direct current offset signal formed by the sensor means S and accumulates charge in integrating capacitors 34a and 34b therein. A resistor 34c is connected in parallel with the capacitors 34a and 34b and a resistor 34d is connected in series between such capacitors to set a time constant for the integrator 34. The voltage represented by the stored charge in the capacitors 34a and 34b of the integrator circuit 34 is provided through an offset amplifier 36 having a control variable feedback resistance or potentiometer 36a, a variable calibration resistance or potentiometer 36b and a bias network 36c permitting a direct current voltmeter 38 to be set to a zero or null reading when the sensor unit S has been moved to the reference position, in a manner to be set forth below.
A two position switch 40 electrically connects the meter 38 to the output from amplifier 36 and the integrating network 34 so that positive and negative polarity direct current offset readings from the sensor unit S may be sensed by the monitor circuit M.
A gain control potentiometer 42 and input resistance 44 electrically connect the collar locator indicator circuit 1 through the control switch K to the collar locator L of the tool T. The potentiometer 42 is adjusted to set the current output level of the collar locator L furnished to the indicator circuit. The indicator circuit I includes an input amplifier 46 electrically connected through rectifying diodes 48a and 48b to a buffer amplifier 50 so that the alternating current output from the collar locator L is rectified and provided as a direct current signal through the amplifier 50 and a connecting resistor 52 to a direct current voltmeter 54 which provides a direct current output reading in response to the proximity of the collar locator L to a drill pipe collar in the drill pipe P, as is conventional in the art.
The electrical portion of the downhole tool T includes a coil 56 and magnetic core 58 of the collar locator L which responds to the proximity of the collar locator L to a casing collar generating an electromotive force (EMF) in the coil 56 which is sensed at the meter 54 of the indicator of the indicator I in the surface electronic portion E.
The sensor S is electrically connected through the wireline W and the line compensating resistance 12 through the multiposition control switch K to the monitor circuit M. The sensor S includes a first ferromagnetic stator core 60 operably connected through the upper bowspring U at a first point of contact to pipe P and a second, or lower, ferromagnetic stator core 62 which is also operably connected to the pipe P at the first contact point thereof by means of the upper bowspring U, as will be set forth below. The sensor unit further includes an intermediate ferromagnetic core 64 operably connected with the first contact point of the pipe along with the stator cores 60 and 62.
The sensor S further includes a first, or upper, ferromagnetic rotor core 66 and a second, or lower, ferromagnetic rotor core 68, each of which is operably connected with a second point of contact of the pipe P by means of the lower bowspring G spaced from the first point of contact with the pipe P. A first or upper inductive coil 70 is mounted between the first stator 60, the intermediate core 64 and the first rotor core 66. Similarly, a second inductive coil 72 is mounted between the second stator core 62, the second rotor core 68 and the intermediate core 64.
The stator core 60, the rotor core 66 and the intermediate core 64 form a ferromagnetic circuit whose reluctance and other ferromagnetic parameters change in response to relative movement between the first and second spaced points of contact with the pipe P, varying the inductance of the inductive coil 70 so that relative movement of the pipe P forms a current sensed by the monitor circuit M of the surface electronics E to indicate that the pipe P is not stuck at the test location. In a like manner, relative movement of the first and second spaced contact points of the pipe changes the parameters of the magnetic circuit formed by the second stator core 62, the second rotor core 68 and the intermediate core 64, varying the inductance of the inductive coil 72 to indicate relative movement of the spaced portions of the pipe P. As will be set forth below, the reference position mounting of the rotor cores and stator cores in the sensor S provides an accurate and sensitive indication of movement of the pipe P during freepoint sensing.
The sensor means S is energized by alternating current sent down from the oscillator 26 of the surface electronics E through the control switch K, the line compensating resistor 12 and the wireline W. Unidirectionally conductive diodes 74 and 76, or other suitable unidirectionally conductive circuit components energize the inductive coil 70 and the second inductive coil 72 on alternate half-cycles 71a and 71b, respectively, (FIG. 4) of the alternating current. Due to the alternate energization of the inductive coils 70 and 72, variations in the reluctance parameters of the ferromagnetic circuit in the sensor S due to relative movement between the upper bowspring U and lower bowspring G during freepoint testing result in an offset direct current, as indicated at 73, to be formed in the sensor S in response to movement of the pipe P. The polarity of the direct current offset further indicates the direction of movement of the pipe P. This direct current offset current provides increased accuracy freepoint readings and permits use of relatively temperature insensitive magnetic components in the sensor S, without requiring additional downhole electronics which are temperature sensitive and thus undesirable for use in deeper wells.
The downhole tool T is movable between a first operating position for sensing operations by the sensor S at a test location in the bore B and a second operating position for backoff operations by the detonator D at the test location. A sensor contact 78 completes an electrical circuit through the sensor S to an electrical ground when the downhole tool is in the first operating position, electrically connecting the sensor S to the wireline W by completing the electrical circuit therebetween. A backoff contact 80 electrically connects the detonator D to the wireline W when the downhole tool T is in the second operating position permitting backoff operations. The sensor contact 78 and the backoff contact 80 are mutually exclusively operable, electrically isolating the sensor means S from the detonator D during downhole operations. This electrical isolation between the sensor S and detonator D protects the ferromagnetic circuits of the sensor D from being excessively or permanently magnetized by the high voltage sent down the wireline W to activate the detonator D, and also prevents power loss in the sensor S by sensor loading during backoff operations insuring full power transfer to the detonator D from the wireline W.
A voltage threshold responsive means, such as a Zener diode 82, electrically connects the backoff contact 80 to a current increasing transformer 84 in the transformer sub F of the downhole tool T. The Zener diode 82 serves as further protection and isolation between the sensor S and the detonator D by preventing sensor voltage from the sensor S from firing the detonator D during sensing operations and other operations.
The transformer 84 has two primary coils 84a electrically connected in parallel between the Zener diode 82 and a tap 84b electrically connected by a return conductor 84e to ground. Two magnetic cores 84c magnetically link each primary 84a of the transformer 84 to a corresponding secondary coil 84d thereof. The secondary coils 84d are electrically connected by a conductor 84f to the detonator D and to electrical ground by a ground conductor 84g. The turns ratio between the primary coils 84a and secondary coils 84d of the transformer 84 is chosen to be a sufficiently large ratio, for example 20:1, so that the level of the electrical current sent from the control circuit C through the switch K over the wireline W to the detonator D is significantly increased in the transformer 84. In this manner, a low level current can be sent over the wireline W, decreasing the voltage drop due to the resistance in the wireline, reducing power loss therein, while insuring sufficient current to ignite the detonator D, particularly those detonators for high temperature well operations which require high current levels to ignite, and permit backoff operations in the well bore B once the stuck point of the pipe P has been located by the sensor S, in a manner to be set forth below. It should be understood that transformers with a single primary coil and secondary coil, or more than two sets of primary and secondary coils are also suitable for use with the present invention. The dual arrangement shown was used as a convenience only to fit the transformer into the successfully constructed embodiment.
The sensor S and time delay means are described in full detail in the above identified parent patent. To the extent the disclosure thereof is necessary to complete this disclosure, it is hereby incorporated by reference as if here set forth in full.
TRANSFORMER SUBASSEMBLY
The transformer subassembly F (FIGS. 2 and 3) receives the reduced current level alternating current from the wireline W through the upper subassemblies including the slip joint J, the collar locator L, the upper bowspring U, the sensor subassembly S and the lower bowspring G. The transformer subassembly F is mounted along a threaded internal surface 310a of a subassembly housing 310 to a threaded lower portion (not shown) of the lower bowspring G. A banana plug 312 is inserted into a contact insert (not shown) mounted in the lower bowspring G, forming an electrical connection therebetween. The banana plug 312 is mounted with an upper surface 314 of an upper insulator plug insert 316. A pie-shaped portion of the insulator plug insert 316 is removed adjacent surfaces 316a and 316b (FIG. 3) to allow clearance for wires, etc. A solder lug 318 is formed extending outwardly from the banana plug 312 on the upper surface 314 of the insulator plug insert 316 in order that an electrical conductor 319 may electrically connect the banana plug 312 to a first contact 82a of the Zener diode 82. The contact 82a and a second contact 82b are formed extending upwardly from the Zener diode 82 into an interior hollow portion 320 of a spacer 322 which supports the insulating block 316. A pair of screws 321 are inserted into threaded sockets in the insulating block 316 and spacer 322 to mount the block 316 with the spacer 322. The Zener diode 82 is mounted with a lock nut 324 which is engaged in a threaded socket 325 of an insulating spacer 326 above an upper plug 328. A set of screws 332 mounts the insulating spacer 326 with the upper plug 328.
A pair of electrical conductors 330 electrically connect the second contact 82b of the Zener diode 82 through the insulating spacer 326 to the input terminals of the pair of primary coils 84a. The conductors 330 preferably pass through suitable grooves (not shown) formed in spacer 326 and plug 328. A second conductive screw 334 in the plug 328 forms an electrical ground.
As has been set forth above, each of the primary coils 84a has an individual common core 84c magnetically linking primary coil 84a with a secondary coil 84d. The turns ratios of the primary coils 84a and the secondary coils 84d are chosen so that a significant increase in the current level sent down the wireline W is formed in the transformers 84 so that reduced current levels may be sent down the wireline W to increased depths and then increased in the transformer F to a sufficiently high level to operate the detonator D. A metallic sleeve 337 is mounted in the housing 310 to retain a suitable protective potting electrical resin for the transformer 84 therein.
The return conductor 84c (FIGS. 1 and 2) electrically connects the side of the primary coils 84a opposite the input terminals to a ground screw 333 mounted in a spacer sleeve 335, electrically grounding the primary coils 84. The return conductor 84e passes through suitable grooves (not shown) formed between the subassembly housing 310, the lower plug 336, a lower insulator 338 and the spacer sleeve 335.
A lower plug 336 is mounted by set screws with the spacer sleeve 335 in the transformer subassembly 310, and a lower insulator 338 is mounted therewith by suitable screws 339 or other fastening means.
The conductor 84f (FIGS. 1 and 2) electrically connects an output terminal of secondary coils 84d of the transformer F to a contact tab 340. The ground conductor 84g electrically grounds the other terminal of the secondary coils 84d to the ground screw 333. The contact tab 340 is formed extending outwardly from a conductive disk 342. The conductive disk 342 is held in place adjacent a lower end 338b of the lower insulator 338 by a contact insert 344 having a threaded external surface for insertion into and engagement with a threaded internal surface formed adjacent a socket 338a in the lower insulator 338. A conventional banana plug 346 is mounted with its associated washer and lock nut atop a lower insulator mount 348 adjacent a lower surface 310b within the transformer housing 310. A conductor passage 310c is formed in the transformer housing 310 extending downwardly from the surface 310b to permit insertion of contact inserts or other suitable conventional electrical connectors so that electrical connection is provided between the banana plug 346 and the detonator subassembly D therebeneath.
A threaded external surface 310d is formed at a lower end of the transformer housing 310 in order that the transformer subassembly F may be mechanically connected with the detonator subassembly D therebeneath. An O-ring 350 or other suitable sealing means is mounted for sealing between the lower end of the transformer housing 310 and the detonator subassembly D.
In operation, as set forth in the above identified parent patent, the control switch K of the surface electronics E may be moved to electrically connect the control circuit C to the wireline W, and switches 20 and 22 are depressed sending alternating current through the current-decreasing transformer 24 through the wireline W, the shooting contact ring 190 and the shooting contacts 180 to the transformer sub F. The current increasing transformer coils 84a in the transformer sub F increase the level of the current from the wireline W so that sufficient amperage is present to ignite the detonator D and free the pipe P above the point where backoff operations are being performed.
TEMPERATURE SENSING APPARATUS
In a remote temperature sensing apparatus A-1 (FIG. 5) of the present invention, like structure and components to that of the apparatus A bear like reference numerals. In the apparatus A-1, the oscillator or alternating current source 26 sends electrical current through the isolation transformer 32 down the wireline W to a remote sensor S-1 mounted in a suitable capsule in the well bore for a sensing temperature conditions therein.
The remote sensor S-1 includes a first resistor 360 electrically connected between the unidirectionally conductive diode 74 and the electrical ground contact 78. The resistor 360 has a resistivity temperature coefficient of substantially zero, so that the resistance value thereof is substantially temperature invariant. The sensor S-1 further includes a second resistor 362 electrically connected between the ground contact 78 and the diode 76. The resistor 362 has a resistivity temperature coefficient of some finite number, such as four parts per thousand. The resistance value of the resistor 362 is selected to equal that of the temperature invariant resistance 360 at a predetermined temperature, for example 0° F. When the sensor S-1 is lowered into the pipe P of the well bore B to sense temperature conditions therein, the resistance value of the resistor 362 changes in accordance with the change in temperature therein, while the resistance value of the resistor 360 remains substantially constant. Accordingly, when the alternating current from the generator 26 is received over the wireline W for positive half-cycles through the diode 74, the current through the resistor 360 does not change. However, on the negative half-cycles through the diode 76, the current through the resistor 362 decreases, forming an offset current which can be monitored by the integrator 34 in the manner set forth above and the voltage level representing the accumulated offset current in the integrator 34 is amplified through the amplifier 36 and provided through the calibration resistor 36b to a meter 38 so that temperature conditions in the well bore may be sensed by the apparatus A-1.
INCLINOMETER
In an inclinometer apparatus A-2 of the present invention (FIG. 6), like structure to that of the apparatus A and A-1 bears like reference numerals. The apparatus A-2 is used for sensing the inclination of a well bore.
The apparatus A-2 receives alternating current operating power from the generator or oscillator 26 which is provided through the isolation transformer 32 down the wireline W to an inclinometer S-2 of the apparatus A-2.
The sensor S-2 is a modified embodiment of the sensor S, being mounted in a ferromagnetic cylindrical case 364. The sensor S-2 has the upper and lower stator cores 60 and 62 and the intermediate core 64 forming a magnetic circuit in conjunction with the ferrous center portion 154a of the shaft 154.
The shaft 154 is mounted at the upper end 154b to a support leaf spring 366 by a screw 368. The support spring 366 engages a cylindrical spacer 370 at outer ends thereof and suspends the shaft 154 therebelow. The support shaft 154 extends from the support spring 366 through an enlarged opening 372 formed in a circular end plate 374 of the sensor S-2. The enlarged opening permits free movement of the shaft 154 with respect to the case 364 of the sensor S-2.
The shaft 154 is mounted at a lower end 154c with a second support leaf spring 376 by a screw 378 or other suitable mounting means. The support spring 376, in a like manner to the support spring 366 is mounted at outer ends thereof with a cylindrical spacer 380. The lower end 154c of the shaft 154 extends through an enlarged opening 382 formed in a lower end plate 384 of the sensor S-2.
The sensor S-2 is calibrated by having the shaft 154a mounted therein so that the inductance of the coils 70 and 72, as influenced by the magnetic circuits formed by the stators 60, 62 and 64 therein, is substantially equal when the sensor S-2 is vertically suspended. The sensor S-2 is mounted in a suitable casing and lowered into the pipe P and the well bore B by the wireline W. As the well bore B deviates from vertical, the weight of the shaft 154 exerting a downward force on the support spring 366 becomes less, due to the deviation from vertical, permitting the support spring 366 to move the shaft 154 upwardly, changing the reluctance parameters of the magnetic circuits affecting the coils 70 and 72, forming the offset current which is accumulated in the integrator 34 to provide a voltage level through the amplifier 36 and the calibrating resistance 36b to the meter 38 in order to indicate the deviation of the well bore B from true vertical.
The motions along the axis of the shaft 164 are very small, in the neighborhood of millionths of an inch or thousandths of an inch at the most. The compressability of the insulator caps on the coils 70 and 72 is sufficient to allow these small motions to in turn produce meaningful results in regard to inclination of the bore hole.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, materials, components, circuit elements, wiring connections and contacts as well as in the details of the illustrated circuitry and construction may be made without departing from the spirit of the invention. | A new and improved wire line operated well tool apparatus and method utilizing a downhole transformer for sensing and testing conditions in a well, such as temperature, incline, and the like. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to a cutting tool with improved properties for metal machining having a substrate of cemented carbide and a hard and wear resistant coating on the surface of said substrate. The coating is deposited by Physical Vapor Deposition (PVD). The coating is composed of metal nitrides in combination with alumina (Al 2 O 3 ). The coating is composed of a laminar multilayered structure. In order to optimize performance, the insert is further treated to have different outer layers on the rake face and flank face, respectively.
Modern high productivity tools for chip forming machining of metals requires reliable tools with excellent wear properties. Since the end of 1960s it is known that tool life can be significantly improved by applying a suitable coating to the surface of the tool. The first coatings for wear applications were made by Chemical Vapor Deposition (CVD) and this coating technique is still widely used for cutting tool applications. Physical Vapor Deposition (PVD) was introduced in the mid 1980s and has since then been further developed from single coatings of stable metallic compounds like TiN or Ti(C,N) to include multicomponent and multilayer coatings also including metastable compounds like (Ti,Al)N or non metallic compounds like Al 2 O 3 .
RF-sputtering of alumina on cemented carbide cutting tools using deposition temperatures up to 900° C. is described in Shinzato et al., Thin Sol. Films, 97 (1982) 333-337. The use of PVD coatings of alumina for wear protection is described in Knotek et al., Surf Coat. Techn., 59 (1993) 14-20, where the alumina is deposited as an outermost layer on a wear resistant carbonitride layer. The alumina layer is said to minimize adhesion wear and acts as a barrier to chemical wear. U.S. Pat. No. 5,879,823 discloses a tool material coated with PVD alumina as one or two out of a layer stack, the non-oxide layers being e.g. TiAl containing. The tool may have an outer layer of TiN. The Al 2 O 3 may be of alpha, kappa, theta, gamma or amorphous type. Alumina coated tools where the oxide polymorph is of gamma type with a 400 or 440 texture are disclosed in U.S. Pat. No. 6,210,726. U.S. Pat. No. 5,310,607 discloses PVD deposited alumina with a content of >5% Cr. A hardness of >20 GPa and a crystal structure of alpha phase is found for Cr contents above 20%. No Cr addition gives amorphous alumina with a hardness of 5 GPa.
Most coated tools today have a top layer of a goldish TiN to make it easy to differentiate by the naked eye between a used and an unused cutting edge eye. TiN is not always the preferred top layer especially not in applications where the chip may adhere to the TiN layer. Partial blasting of coatings is disclosed in EP-A-1193328 with the purpose to enable wear detection at the same time as the beneficial properties of the underlying coating are retained. Wear on the rake face is mostly chemical in nature and requires a chemically stable compound whereas wear on the flank face is mostly mechanical in nature and requires a harder and abrasive resistant compound.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention is to provide an improved cutting tool composition with a multilayer coating.
It is a further object of the present invention to further improve the performance of PVD coated cutting tools using the concept of different outer layers on the rake and flank face respectively.
In one aspect of the invention, there is provided a PVD coated cemented carbide insert having an upper face (rake face), an opposite face and at least one clearance face intersecting said upper and opposite faces to define cutting edges wherein the cemented carbide has a composition of from about 86 to about 90 weight % WC, from about 1 to about 2 weight % (Ta,Nb)C and from about 8 to about 13 weight % Co, and coated with a hard layer system, having a total thickness of from about 3 to about 30 μm, comprising a first layer of (Ti,Al)N with a thickness of from about 1 to about 5 μm, an alumina layer with a thickness of from about 1 to about 4 μm, a ((Ti,Al)N+alumina)*N multilayer, where N≧2, with a thickness of less than about 0.5 μm, and a ZrN layer with a thickness of less than about 1 μm, the ZrN-layer missing on the rake face and on the edge line wherein the (Ti,Al)N-layers preferably have an atomic composition of Ti/Al of greater than about 60/40 and less than about 70/30.
In another aspect of the invention, there is provided a method of making a coated cutting tool insert having an upper face (rake face), an opposite face and at least one clearance face intersecting said upper and opposite faces to define cutting edges, comprising the following steps: providing a cemented carbide substrate with a composition of from about 86 to about 90 weight % WC, from about 1 to about 2 weight % (Ta,Nb)C and from about 8 to about 13 weight % Co, depositing onto the cemented carbide substrate by PVD, a hard layer system with a total thickness of from about 3 to about 30 μm, and comprising a first layer of (Ti,Al)N with a thickness of from about 1 to about 5 μm, an alumina layer with a thickness of from about 1 to about 4 μm, a ((Ti,Al)N+alumina)*N multilayer, where N≧2, with a thickness of less than about 0.5 μm, and an outermost ZrN layer with a thickness of less than about 1 μm, wherein the (Ti,Al)N-layers preferably have an atomic composition of Ti/Al greater than about 60/40 and less than about 70/30, and removing said ZrN-layer on the rake face and on the edge line by a post-treatment.
DETAILED DESCRIPTION OF THE INVENTION
The coating, preferably made by PVD, has a (Ti,Al)N-compound next to the substrate, an alumina layer on top of the (Ti,Al)N-layer and at least two further alternating layers of (Ti,Al)N and alumina and an outermost layer of ZrN. The ZrN layer is removed on the rake face in a post treatment, preferably blasting or brushing. For complete removal of the ZrN layer on the rake face several repeated brushings or blastings are often necessary. An incomplete removal often results in local welding of the ZrN residuals to the chip which reduces tool life. In order to reduce the adherence of the top ZrN layer, an intermediate layer of substoichiometric ZrN 1-x is deposited on the alumina layer, underneath the ZrN layer. The substoichiometric ZrN 1-x , has a reduced strength and facilitates the removal of the top ZrN layer.
According to the present invention there is now provided a cutting tool insert, having an upper face (rake face), an opposite face and at least one clearance face intersecting said upper and opposite faces to define cutting edges, comprising a cemented carbide substrate and a hard layer system. The cemented carbide has a composition of from about 86 to about 90 weight % WC, from about 1 to about 2 weight % (Ta,Nb)C and from about 8 to about 13 weight % Co, preferably from about 88 to about 89 weight % WC, from about 1.2 to about 1.8 weight % (Ta,Nb)C and from about 10 to about 11 weight % Co. The hard layer system has a total thickness of from about 3 to about 30 μm, and comprises
a first layer of (Ti,Al)N with a thickness of from about 1 to about 5, preferably from about 2 to about 4 μm,
an alumina layer, preferably γ-alumina, with a thickness of from about 1 to about 4 preferably from about 1 to about 2 μm,
a ((Ti,Al)N+alumina)*N multilayer, where N≧2 with a thickness of less than about 0.5 μm, preferably from about 0.1 to about 0.3 μm, preferably a thin, preferably less than about 0.1 μm, layer of substoichiometric ZrN 1-x , preferably x=from about 0.01 to about 0.1 and a ZrN layer with a thickness of from about less than 1 μm, preferably from about 0.1 to about 0.6 μm, the ZrN-layer missing on the rake face and on the edge line
wherein the (Ti,Al)N-layers preferably have an atomic composition of Al/Ti of greater than about 60/40 to less than about 70/30 most preferably Al/Ti is about 67/33.
The present invention also relates to a method of making a coated cutting tool insert, having an upper face (rake face), an opposite face and at least one clearance face intersecting said upper and opposite faces to define cutting edges, comprising the following steps:
providing a cemented carbide substrate with a composition of from about 86 to about 90 weight % WC, from about 1 to about 2 weight % (Ta,Nb)C and from about 8 to about 13 weight % Co, preferably from about 88 to about 89 weight % WC, from about 1.2 to about 1.8 weight % (Ta,Nb)C and from about 10 to about 11 weight % Co; depositing onto the cemented carbide substrate, using PVD methods, a hard layer system with a total thickness of from about 3 to about 30 μm, and comprising
a first layer of (Ti,Al)N with a thickness of from about 1 to about 5 preferably from about 2 to about 4 μm, an alumina layer, preferably 7-alumina, with a thickness of from about 1 to about 4 preferably from about 1 to about 2 μm, a ((Ti,Al)N+alumina)*N multilayer, where N≧2 with a thickness of less than about 0.5 μm, preferably from about 0.1 to about 0.3 μm, preferably a thin, preferably less than about 0.1 μm, layer of substoichiometric ZrN 1-x , preferably x=from about 0.01 to about 0.1 and an outermost ZrN layer with a thickness of less than about 1 μm, preferably from about 0.1 to about 0.6 μm wherein the (Ti,Al)N-layers preferably have an atomic composition Al/Ti of greater than about 60/40 to less than about 70/30 most preferably Al/Ti is about 67/33.
removing said ZrN-layer on the rake face and on the edge line by a post-treatment, preferably by brushing or blasting.
The invention is additionally illustrated in connection with the following examples, which are to be considered as illustrative of the present invention. It should be understood, however, that the invention is not limited to the specific details of the examples.
Example 1
Cemented carbide inserts ADMT 160608R with the composition 88 weight % WC, 1.5 weight % (Ta,Nb)C and 10.5 weight % Co were coated with PVD-technique according to the following sequences in one process
Version A; a layer stack (Ti 0.33 Al 0.67 N—Al 2 O 3 —Ti 0.33 Al 0.67 N—Al 2 O 3 —Ti 0.33 Al 0.67 N—Al 2 O 3 ),
Version B; a layer stack (Ti 0.33 Al 0.67 N—Al 2 O 3 )
Version C; a Ti 0.33 Al 0.67 N layer.
The inserts were tested in a dry shoulder milling application.
Work piece material: Martensitic stainless steel X90CrMoV18 (1.4112).
Cutting speed: 140 m/min
Tool life criteria: Number of produced parts
TABLE 1
Tool life parts produced after edge milling
Coating
Ti 0.33 Al 0.67 N
Ti 0.33 Al 0.67 N—Al 2 O 3
3 × (Ti 0.33 Al 0.67 N—Al 2 O 3 )
Tool
3
4
7
life
parts
The result shows the effect of an increasing layer thickness on tool life in edge milling.
EXAMPLE 2
Cemented carbide inserts ADMT 160608R with the composition 88 weight % WC, 1.5 weight % (Ta,Nb)C and 10.5 weight % Co were coated with PVD-technique according to the following sequence in one process: 3 μm (Ti,Al)N (Al/Ti 67/33%), 1,5 μm nanocrystalline γ-alumina, 0.2 μm (Ti,Al)N (Al/Ti 67/33%), 0.2 μm nanocrystalline γ-alumina, 0.1 μm (Ti,Al)N (Al/Ti 67/33%), 0.1 μm nanocrystalline γ-alumina, 0.1-0.5 μm ZrN.
The top layer of ZrN was blasted off on the rake face using alumina in a wet blasting process.
Both blasted and unblasted inserts were used to edge mill a Ti-alloy (toughness 1400 N/mm 2 ).
The maximum flank wear was measured after a cutting distance of 890 mm with the following result.
TABLE 2
Wear (mm) after edge milling
Untreated
ZrN removed on rake face
Maximum flank wear
0.40-0.45
0.15-0.23
Maximum radius wear
0.23-0.3
0.10-0.13
It is clearly shown that the removal of ZrN on the top rake face leads to a considerably lower wear.
Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims. | The present invention describes a cutting tool with improved properties for metal machining having a substrate of cemented carbide and a hard and wear resistant coating on the surface of said substrate. The coating is deposited by Physical Vapor Deposition (PVD). The coating is composed of metal nitrides in combination with alumina (Al 2 O 3 ). The coating is composed of a laminar multilayered structure. The insert is further treated to have different outer layers on the rake face and flank face respectively. | 8 |
GOVERNMENT SPONSORSHIP
[0001] Aspects of the instant disclosure were sponsored by that certain Telemedicine and Technology Research Center for the Army of the United States of America (TATRC) Contract, denoted W81XWH-05-2-0024, wherein the Principal Investigator is the first named inventor of the instant patent application. Likewise, the Center for Advanced Surgical and Interventional Technologies (CASIT) was initiated both by philanthropic donative instruments and TATRC funding.
BACKGROUND OF THE DISCLOSURE
[0002] The present disclosure relates to improved tactile feedback systems, products, process and methods and medical devices for enhancement of tactile feedback. In particular, the present disclosure relates to optimized haptic interfacing processes and products thereby.
[0003] Minimally invasive surgery (MIS) has revolutionized surgical care and treatment, reducing trauma to the patient, decreasing the need for pain medications, and shortening recovery times and hospital stays. MIS has been used in the military and is also proposed for battlefield surgery pods. One drawback of current laparoscopic techniques is the reduction of tactile, or haptic, feedback to the surgeon. This has likely limited the expansion of MIS applications and contributed to an increased learning curve for surgeons. Robotic MIS offers improved range of motion and other technical advantages, but is characterized by a total loss of haptic feedback.
[0004] Those skilled in the art readily understand that numerous desiderata relating to the “hand” or feel of remotely actuated devices have created a series of longstanding needs. The instant disclosure offers for consideration numerous aspects which artisans shall embrace as new ways to address these traditional surgical issues and other things. According to the instant teachings, improved tactile feedback enables numerous automatic and robotic systems to function at a new level by enriching the user interface for prosthetics, orthotics, video-games and simulations useful from applications ranging from sensory neuropathy addressing devices to new filmed audio and video driven systems.
SUMMARY OF THE DISCLOSURE
[0005] Briefly stated, the invention includes a modular, scalable, layerable balloon actuator or actuator array. The miniaturized actuator array is, in one embodiment, mounted on the hand controls of a surgical robotic system, and pressure or force input is applied to the surgeon's fingers. The input to the fingers is proportional to the applied force or pressure that is sensed on a separate sensor array, which is mounted on the surfaces of the object to be physically manipulated.
[0006] According to embodiments of the present invention, there is provided an improved pneumatic tactile system comprising in combination, at least an actuator, sensors operatively linked to the at least an actuator and a control system for regulating input in proportion to applied force and pressure, whereby a latency period between movement of the user and feedback transmitted to equipment spans a time period of less than at least about 300 milliseconds.
[0007] According to the further embodiments of the present invention there is provided a pneumatic tactile apparatus comprising, in combination, a substrate, balloon membrane mounted between a user interface and an apparatus to be manipulated.
[0008] According to still further embodiments of the present invention there is provided a haptic feedback system which is wireless and scalable comprised of a sensor array, a system controller and a plurality of pneumatically controlled actuators, wherein an air source is a gas.
[0009] The force is translated to pressure using a control system; which includes electronic and pneumatic components. These components (actuator, sensor, and control system) comprise a Haptic Feedback System. This haptic feedback system can enable, the detection of force and tactile information on tissues and sutures with high spatial and temporal resolution.
[0010] This technology shortens the learning curve for MIS training, expands the application of MIS techniques in surgery, and enhances telementoring and telesurgery applications. The actuator is modular scalable, layerable, compact, configurable, flexible, and conformable. It is therefore readily adaptable to future surgical robotic systems, and can be applied to prosthetics, orthotics, and persons with sensory neuropathy, as well as other robotic applications, simulating machines and apparatus and user-interfacing systems for video-gaming.
[0011] According to a feature of the present disclosure there is provided an improved pneumatic tactile system, which comprises in combination a substrate and a balloon membrane to be mounted between a user interface and an apparatus to be manipulated, wherein the apparatus to be manipulated is at least one of an orthotic and a prosthetic.
[0012] According to another feature of the instant haptic feedback system which is wireless and scalable comprising a sensor array, a system controller, a plurality or array of pneumatically controlled actuators, and at least a wireless controller, whereby the process is used with at least one of a video-gaming system and a simulation based on audio and video input and feedback.
DRAWINGS
[0013] The above-mentioned features and objects of the present disclosure will become more apparent with reference to the following description taken in conjunction with the accompanying drawings wherein like reference numerals denote like elements, to the extent feasible and consistent wherein:
[0014] FIG. 1 is a generalized schematic showing a system according to teachings of the present invention;
[0015] FIG. 2 is an engineering schematic of embodiments according to the teachings of the present invention;
[0016] FIG. 3 is another detailed engineering schematic showing aspects of the instant system; and
[0017] FIG. 4 is a view of one version of a user interface according to the present invention.
DETAILED DESCRIPTION
[0018] It will be understood that various details of the presently disclosed subject matter may be changed without departing from the scope of the presently disclosed subject matter. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Artisans will readily grasp use of the instant teachings in their respective fields, from minimally invasive surgery to robotics to filmed entertainment and video-gaming.
[0019] The present inventors have discovered that lack of haptic, or force, feedback limits the surgeon's ability to apply robotically assisted surgical systems and complex laparoscopic techniques to technically demanding procedures. Without haptic feedback, surgeons must rely primarily on visual cues, and are thus deprived of their tactile senses when tying sutures and manipulating tissues. This has delayed advancement of the field, and underscores the need for improved user interface systems which “feel” like the process they are replacing.
[0020] Likewise, those involved in simulations, video gaming, filmed entertainment and related industries have needs addressed by the instant system. Artisans will understand readily how to use the instant system for applications in their respective field of use. For example, virtual reality-based gaming systems allowing users to “sense” based on their actions have needed better haptic feedback for some time.
[0021] During robotic surgery, surgeons must rely on visual cues alone. This likely contributes to longer learning curves for MIS procedures, and decreases the surgeon's ability to detect tissue characteristics, which can lead to inadvertent tissue damage and surgical errors. Addition of haptic feedback capabilities to complex laparoscopic and robot-assisted surgical systems improves the quality and safety of surgical procedures and allows for expansion of these techniques to other applications.
[0022] To address the feedback limitations of current robot-assisted surgical systems, the development of an adaptable, reliable, scalable, and affordable haptic feedback system is offered for consideration by the instant systems. The concept of haptic feedback and its application to MIS have previously been investigated; however, current technologies have limited applicability to existing laparoscopic and robotic tool systems. These limitations include excessive manufacturing costs, bulky and complicated designs, and long learning curves. Previously developed haptic feedback devices for robotic surgical systems require redesigning and reengineering of the systems themselves, greatly increasing cost and complexity of the final integrated system designs.
[0023] A pneumatic balloon-based haptic feedback system has previously been proposed by another group for laparoscopic surgery; however the actuator design is impractical for attachment onto laparoscopic or robotic tools due to its bulky design and lack of modularity, scalability, uniformity, and layerability as has been detailed in the literature. Artisans can access hundreds of articles explaining the shortcomings of known systems, thus, further detail regarding the same is omitted from this discussion. However, exemplary references are listed for this purpose.
[0024] Key benefits of the instant system, according to embodiments of the present invention include scalability and adaptability to various laparoscopic and robotic surgical tools, as well being easily and practically combined with other robotic or prosthetic applications. By developing a scalable and modular wireless haptic feedback system, complicated system redesigns and high system integration costs can be avoided and teaming curves are shortened.
[0025] Referring to FIG. 1 through FIG. 4 , a FlexiForce (Tekscan, Inc.) A201 piezoresistive sensor 11 has been selected as an exemplary force sensor, according to an illustrative, but not limiting, embodiment. Upon application of a force or pressure to the sensor surface, a proportional voltage change is detectable. A microcontroller unit 13 has been programmed to translate the voltage input from sensor 11 to a proportional pressure output, which will actuate a pneumatic balloon. Various prototype balloon actuators have been manufactured from, for example, Soda Clear Dragon Skin brand of silicone rubber film (Smooth-on®, Inc.) and macromolded polydimethylsiloxane (PDMS) base.
[0026] Testing has demonstrated a maximum actuation pressure of 15 psi over 75 actuation cycles for a 300 μm thick membrane. Investigators in research groups were able to consistently distinguish between three actuation levels over the 15 psi range. Artisans readily understand these parameters, and how they relate to the instant systems; as shown in FIG. 4 , user interface 3 allows the operator to react and to act on forces transmitted through various depicted system embodiments.
[0027] Membranes have been fabricated with thicknesses ranging from 100 μm to 500 μm, either in a single or multi-layer configuration. Substrates have been fabricated with various arrays, channels, and tubing configurations and dimensions—all a result of the modularity and scalability of the actuator design. Surgeons have already mastered use of the instant system and use it for numbers of procedures, in addition to training and education applications developed.
[0028] FIG. 2 and FIG. 3 shows an alternate design which is a more complex prototype consisting of multi-element sensor 11 and actuator arrays 16 , 17 . This added complexity improves the resolution of the system and will also allow the force sensor to act as a slip sensor, measuring shear as well as compressive forces; that is, the detection of objects or tissues slipping from the grasper, in one embodiment. The end result being that the instant system has a “hand” or “feel” allowing the user to operate the system as if there were nothing between the user and the object to be manipulated. Referring now to FIG. 3 , also the skilled in the art will understand based upon the foregoing discussion, figures and the claims which are appended hereto, how input from sensor becomes output from sensor traveling through chip 22 , which may be any customized or designed element as is available to then transfers output as depicted.
[0029] According to embodiments, for example, like that shown in FIG. 2 , micro fabrication of the instant teachings using micro-electro-mechanical systems (MEMS) technology has been accomplished. Psychomotor testing validated and enables the team to optimize the balloon array characteristics, including the balloon diameter, spacing, inflation pressure and maximum deflection. In their way, surgery, telementoring has become possible with use of interface 3 .
[0030] According to embodiments of these inventions, an optimized haptic feedback system is effective to be retrofitted onto the robotic surgical instruments for in vitro and in vivo clinical testing, on an ongoing basis. It is respectfully proposed that the instant improvements over the state of the art constitute progress in science and the useful arts, and permit users to have haptic input making many tasks easier.
[0031] While the apparatus and method have been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure need not be limited to the disclosed embodiments. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures. The present disclosure includes any and all embodiments of the following claims.
REFERENCES
[0032] The references listed below are incorporated herein by reference only as appropriate under National law, per the Paris Convention to the extent that they supplement, explain, provide a background for or teach methodology, techniques and/or processes employed herein. All cited publications referred to in this application are herein expressly incorporated by reference, as appropriate under national law mindful that those skilled in the art are aware of those systems described and how the present invention relates to and interfaces with them.
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[0069] Tekscan, Inc., http://www.tekscan.com/flexiforce/specs flexiforce.html. | A modular, scalable, layerable balloon actuator or actuator array. The miniaturized actuator array can be mounted on the hand controls of a surgical robotic system, and pressure or force input is applied to the surgeon's fingers. The input to the fingers is proportional to the applied force or pressure that is sensed on a separate sensor array, which is mounted on the surfaces of the object to be physically manipulated. The force is translated to pressure using a control system, which includes electronic and pneumatic components. The Novel enhanced haptic feedback system enables the detection of force and tactile information on tissues and sutures with high spatial and temporal resolution. This technology shortens the learning curve for MIS training, expands the application of MIS techniques in surgery, and enhances telementoring and teiesurgery applications. The actuator is modular scalable, Iayerable, compact, configurable, flexible, and conformable. It is therefore designed such that it can be adapted to future surgical robotic systems, and can be applied to prosthetics, orthotics, and persons with sensory neuropathy, as well as other robotic applications, simulating machines and apparatus and user-interfacing systems for video-gaming. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
The invention of the present application claims priority based on U.S. Provisional Application Ser. No. 60/490,624 filed on Jul. 28, 2003.
BACKGROUND OF THE INVENTION
This invention relates to EMD locomotive engine protection devices and more particularly to preventing conditions causing the trip of the device in an EMD locomotive engine during a computer controlled automatic engine restart.
Railway locomotives are off service for substantial periods of time and are generally shut down when they are not going to be in use for extended time periods. Since some locomotive systems may be harmed if the engine is shut down for too long, there are automated systems designed to stop and restart an engine automatically in the absence of personnel. Whether an engine is being started automatically or manually there are engine protective devices designed to sense certain conditions in an engine's systems during start up and running which will shut an engine down under certain conditions. Unfortunately, and especially after an EMD locomotive engine has been shut down for a long period of time, transient conditions on start-up may be sensed by such protective devices and result in the engine being immediately shut down again. This condition defeats the advantage of an automatic engine start/stop system (AESS) and may require the need for personnel to be available to restart such an engine by overriding the protective devices.
One protective device for engines manufactured by the Electro-Motive Division of General Motors (EMD) is a differential water and crankcase pressure detector system. This device monitors for abnormalities in the engine cooling system and crankcase pressure. If potentially harmful abnormalities are sensed the engine is shut down. Sometimes sensed abnormalities at engine start-up due to transient conditions, such as low coolant system pressure, cause this protective device to produce an unnecessary engine shutdown. In these EMD protective devices of Electro-Motive Division of General Motors locomotive engines there are manual resets which require the presence of qualified personnel to restart the engine, thus often defeating the advantage of an AESS system on such engines.
SUMMARY OF THE INVENTION
The present invention overcomes the above-described disadvantages and difficulties associated with EMD engine protective devices by providing systems and methods which temporarily inhibit their function on engine start-up while utilizing an AESS system.
One aspect of the present invention provides a system for overriding an EMD locomotive engine protective device which includes a low water pressure sensing device in communication with the engine cooling system for shutting down the engine when low water pressure in the engine is sensed, the override system comprising a water assist pump connected to a source of water and communicating with the protective device for supplying pressurized water to the low water pressure sensing device to maintain relatively high water pressure to prevent the device from shutting down the engine; and a controller for activating the water assist pump during start up of the engine. The controller preferably operates the water assist pump during priming and cranking of the engine and can be used in conjunction with an AESS system.
A further aspect of the present invention provides a system for overriding an EMD locomotive engine protective device which includes first and second interconnected diaphragms, one side of the first diaphragm in communication with a discharge from an engine water pump and an opposite side of the first diaphragm in communication with an inlet of the engine water pump and a first side of the second diaphragm in communication with an engine air box such that the diaphragms are moved by differential pressure across the diaphragms when the differential pressure across the first diaphragm becomes less than the pressure of the engine's air pressure box acting on the second diaphragm, indicating low water pressure in a cooling system of an EMD locomotive engine, the override system comprising a water assist pump connected to a source of water and communicating with the protective device for supplying pressurized water to the one side of the first diaphragm in the engine protective device; and a controller for activating the water assist pump during start up of the engine.
Another aspect of the present invention includes a method of overriding an EMD locomotive engine protective device which includes a low water pressure sensing device in communication with the engine cooling system for shutting down the engine when low water pressure in the engine is sensed, the override method comprising activating a water assist pump in communication with the engine cooling system during engine start-up to supply water pressure to the protective device such that the protective device will not shut down the engine. This aspect also preferably includes the step wherein the water assist pump is operated during priming and cranking of the engine. This method also preferably includes the activating step being used in conjunction with an automatic engine start/stop system activation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of the engine cooling system of an EMD engine with an AESS system and components including the preferred embodiment of the present invention;
FIG. 2 is a schematic view of a positive crankcase pressure condition in an EMD engine;
FIG. 3 is a schematic view of a low differential water pressure condition;
FIG. 4 is a schematic of activation of the system of FIG. 1 during engine priming mode;
FIG. 5 is a schematic of activation of the system of FIG. 1 during engine cranking mode; and
FIG. 6 is a timing chart for energizing and de-energizing various components of the system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As illustrated in FIG. 1 , during operation of the EMD engine (not shown) water is supplied to the engine from a water source such as water tank 10 through an engine water pump 12 and water supply line 14 . A low water pressure sensing device 16 is in communication with the water supply line 14 connected to the engine to detect a low water condition. As discussed more fully below, if a low water condition that could be harmful to the engine is detected, the engine is shut down. In one preferred embodiment of the present invention, connected to the water supply line and in communication with the low water pressure sensing device 16 is a water assist pump 20 . The water assist pump 20 is an electric pump controlled by the automatic engine start/stop (AESS) system computerized controller 22 . When activated, the pump 20 draws water from the water supply line 14 , such as at connection 15 coming from the water supply tank 10 , and through line 24 connected to the inlet 26 of the pump 20 . Water is then discharged from outlet 28 of pump 20 into the low water pressure sensing device supply line 30 as described in more detail below.
Referring now to FIG. 2 , a schematic representation of an EMD low water protective device is shown generally at 40 . Such an EMD protective device 40 is included in many locomotives equipped with EMD engines. The engine water pump discharge pressure is supplied at 42 ; the engine water pump inlet pressure is supplied at 44 ; the engine air box pressure is supplied at 46 and the oil inlet from the governor is at 48 . An oil relief valve 50 is shown in the latched position in FIG. 2 and in an unlatched position or tripped position in FIG. 3 . A first diaphragm 52 is positioned between the water pump discharge pressure 42 and the engine water pump inlet pressure 44 . A second diaphragm 54 is positioned on a side of the air box pressure, and the two diaphragms are interconnected such that a predetermined imbalance in the water pump pressure across the first diaphragm 52 causes the oil relief valve 50 to unlatch.
During standard operation of the low water protective device, when the differential pressure across the engine water pump 12 becomes less than the air box pressure the oil relief valve 50 is tripped as shown in FIG. 3 , causing the oil drain valve to open and dump engine oil from the low oil sensing device of the engine governor (not shown). The governor senses low oil pressure and initiates low oil shut down of the engine.
When, in one embodiment with the present invention, the water assist pump 20 is activated it adds water pressure to the engine water pump discharge pressure at 42 preventing it from falling sufficiently that the pressure differential across diaphragm 52 falls below the air box pressure thus preventing the low water detection device from triggering and shutting down the engine.
Generally speaking, when the AESS controller 22 activates the automatic start procedure it rings a warning bell 60 for 30 seconds and completes the circuit from the battery to the water assist pump 20 which causes pump 20 to pump cooling water and pressurize the cooling system. The priming period lasts for 15 to 20 seconds. The engine cranking procedure then occurs.
In accordance with AESS procedure the engine will crank for not more than 20 seconds. If the engine has started within that time period the AESS system will de-energize the water assist pump 20 . In a case when the engine did not start the AESS system will de-energize the water assist pump 20 and repeat the starting procedure in 2 minutes.
Referring now to FIGS. 4 and 5 , although the electrical connections for the water assist pump 20 can be done in many ways, these figures and the below disclosure illustrate one such connection system as an example only. When the AESS controller 22 activates the automatic engine start procedure it energizes Engine Start Relay 62 , and thus complete the circuit to water assist pump 20 from the battery switch via Local Control circuit breaker 64 , normally closed interlock of No Voltage Relay 66 and interlock of Engine Start Relay 62 and then returning to the Local Control circuit Breaker 68 and Battery Switch.
The priming period, as shown in FIG. 5 , lasts for 15 to 20 seconds. The engine cranking procedure then occurs as shown in FIG. 5 . During this procedure Engine Start Relay 70 is activated in addition to Engine Start Relay 62 . Interlocks of Engine start Relays 62 and 70 bypass a manual switch 72 and via interlocks of a Thermal Overload Relay 74 , Fuel Pump Relay 76 and second normally closed interlock of relay 78 energize Starting Auxiliary Contactor 80 . At the same time, Governor Assist Pump 82 is activated. The cranking lasts for 15 to 20 seconds. If the engine start was successful the relay 78 will pick up and open the circuit to the Water Assist Pump, the Governor Assist Pump 82 and the Starting Auxiliary Contactor 80 and AESS will de-energize Engine Start Relays 62 and 70 and Crank Setup Relay 84 . If the engine did not start AESS controller will de-energize Engine Start Relays 62 and 70 and repeat the starting procedure in 2 minutes.
In accordance with AESS procedure, the engine will crank for not more than 20 seconds. If the engine has started within that time period the AESS system will de-energize Engine Start Relays 62 and 70 and Crank Setup Relay 84 .
The above sequencing is shown in bar graph form in FIG. 6 to provide a better understanding of when the various components are activated and not activated. As shown in FIG. 6 by bar 90 , the water assist pump 20 is preferably activated during priming of the engine as well as during cranking. This allows the pressure to be developed in the low water pressure protective device 40 early in the starting process. As shown by bar 92 the Crank Setup Relay 84 is activated when the AESS system is stopped-as well as during the AESS priming period and the AESS cranking period. The Engine Start Relay 62 is engaged during AESS priming and cranking, as shown by bar 94 , and Engine Start Relay 70 is engaged only during the cranking period, as shown by bar 96 .
When introducing elements or features of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those listed.
As various changes could be made in the above embodiments without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | A system for overriding an EMD locomotive engine protective device which includes a low water pressure sensing device in communication with the engine cooling system for shutting down the engine when low water pressure in the engine is sensed, the override system comprising a water assist pump connected to a source of water and communicating with the protective device for supplying pressurized water to the low water pressure sensing device to maintain relatively high water pressure to prevent the device from shutting down the engine; and a controller for activating the water assist pump during start up of the engine. | 5 |
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to optical dispersion compensators and, more particularly, to a method and apparatus for implementing a colorless Mach-Zehnder-interferometer-based tunable dispersion compensator.
BACKGROUND OF THE INVENTION
Optical signal dispersion compensators can correct for chromatic dispersion in optical fiber and are especially useful for bit rates 10 Gb/s and higher. Furthermore, it is advantageous for the dispersion compensator to have an adjustable amount of dispersion, facilitating system installation. It is also advantageous if the tunable dispersion compensator (TDC) is colorless, i.e., one device can compensate many channels simultaneously or be selectable to compensate any channel in the system.
Previously proposed colorless TDCs include ring resonators [1] , the virtually imaged phased array (VIPA) [2] , cascaded Mach-Zehnder interferometers (MZIs) [3,4,5] , temperature-tuned etalons [6] , waveguide grating routers (WGRs) with thermal lenses [7] , and bulk gratings with deformable mirrors [0] . The bracketed references [1] refer to publications listed in the attached Reference list. The cascaded MZI approach is particularly promising since it exhibits low loss, can be made with standard silica waveguides, and can be compact. However, previous MZI-based TDCs required 8 stages and 17 control voltages in one case [3] and 6 stages with 13 control voltages in two others [4, 5] . This large number of stages and control voltages is expensive and power-consuming to fabricate and operate, especially when compensating 10 Gb/s signals. Because fabrication accuracy cannot guarantee the relative phases of such long path-length differences, every stage of every device must be individually characterized. Also, a large number of stages often results in a high optical loss and a large form factor. Additionally, the more the stages, the more difficult it is to achieve polarization independence.
What is desired is a simplified MZI-based TDCs having reduced number of stages and control voltages.
SUMMARY OF THE INVENTION
In accordance with the present invention, I disclose a method and apparatus for implementing a new type of colorless Mach-Zehnder-interferometer (MZI)-based tunable dispersion compensator (TDC) that has only three MZI stages (two in a reflective version) and two adjustable couplers which are responsive to one control voltage, making it compact, low power, and simple to fabricate, test, and operate. Such an MZI-based TDC with a 25-GHz-free-spectral-range version can compensate ˜±2100 ps/nm for 10 Gb/s signals. Having a free-spectral range equal to the system channel spacing divided by an integer makes it possible for the TDC to compensate many channels simultaneously.
More particularly, one embodiment of my tunable chromatic optical signal dispersion compensator comprises
three cascaded Mach-Zehnder interferometers, MZIs, a first MZI including a fixed 50/50 coupler for receiving an input optical signal, a second MZI including a first adjustable coupler that is shared with the first MZI and a second adjustable coupler that is shared a third MZI, and the third MZI including a fixed 50/50 coupler for outputting a dispersion-adjusted output optical signal,
wherein the path-length difference between the two arms in the second MZI is twice that of the first MZI, and the path-length difference between the two arms in the first MZI is equal to that of the third MZI and
wherein said first and second shared adjustable couplers are adjusted with equal coupling ratios using a single control signal to provide adjustable dispersion compensation to the output signal.
In a reflective embodiment, my tunable chromatic optical signal dispersion compensator comprises
a first MZI including a fixed 50/50 coupler for receiving an input optical signal at a first port and an adjustable coupler, that is shared with a second reflective MZI, the path-length difference between the two arms in the second MZI is equal to that of the first MZI and
wherein the adjustable coupler is responsive to a control signal for controlling the amount of signal dispersion added by said compensator to the input optical signal to form the output optical signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully appreciated by consideration of the following Detailed Description, which should be read in light of the accompanying drawing in which:
FIG. 1 illustrates, in accordance with the present invention, a tunable dispersion compensator (TDC) that has only three stages and one control voltage.
FIG. 2 illustrates the TDC of FIG. 1 where the adjustable couplers are each implemented using an MZI-based adjustable coupler.
FIG. 3 illustrates the electrical layout for using a single control signal, C 1 , to control the two MZI-based adjustable couplers of FIG. 2 .
FIG. 4 illustrates, in accordance with the present invention, a reflective design of a tunable dispersion compensator (TDC) that uses only one control voltage.
FIGS. 5A and 5B illustratively show the transmissivity and group-delay characteristics of my TDC at three different settings of the adjustable coupler(s).
FIGS. 6A and 6B show the use of my TDC in illustrative optical transmission systems.
FIGS. 7 a and 7 B show my TDC arranged together with an Erbium amplifier.
In the following description, identical element designations in different figures represent identical elements. Additionally in the element designations, the first digit refers to the figure in which that element is first located (e.g., 101 is first located in FIG. 1 ).
DETAILED DESCRIPTION
With reference to FIG. 1 there is shown, in accordance with the present invention, an illustrative diagram of my tunable dispersion compensator (TDC) that has only three stages and uses one control voltage. The three stages 103 , 105 , and 107 are implemented using Mach-Zehnder-interferometers (MZIs). The first and second MZIs 103 , 105 share an adjustable coupler 104 and the second and third MZIs 105 , 107 share an adjustable coupler 106 . The two adjustable couplers 104 , 106 are always set equally. The first and third MZI have path-length differences ΔL, and the center MZI has a path-length difference of 2ΔL (plus any phase offset from the couplers).
The TDC operates as follows. An input optical signal at port 101 is split equally to the two arms of the first MZI 103 by the y-branch coupler 102 . In the first MZI 103 , one arm is longer, by ΔL, than the other arm so that when the optical signals are recombined in the first adjustable coupler 104 , the amount of light sent to each of the two arms of the second MZI 105 depends on the wavelength. The first adjustable coupler 104 in response to a control signal C 1 controls the sign and amount of dispersion introduced to the signals outputted from the coupler 104 to the arms of the second MZI 105 . Similarly, the second adjustable coupler 106 in response to a control signal C 1 controls the sign and amount of dispersion introduced to the signals received from the arms of the second MZI 105 and outputted from the coupler 106 to the arms of the third MZI 107 . If positive dispersion is desired, a predetermined control signal C 1 to adjustable couplers 104 , 106 is used to enable the longer wavelengths to predominantly travel the longer arms of the second MZI 105 and third MZI 107 , respectively. The third MZI 107 then performs a function similar to the first MZI in that the wavelengths on its arms are recombined in the final y-branch coupler 108 and are sent to the output port 109 .
Note that when the TDC device is set for zero dispersion, the two adjustable couplers 104 , 106 are 100/0 (i.e., the couplers perform a simple cross-connect function—an input to the upper left-hand port of the adjustable coupler goes to the lower right-hand output port of the adjustable coupler and vice versa). In such a zero-dispersion case, the optical signals through the TDC traverse equal path lengths. While only the differential arm lengths are shown in FIG. 1 , in MZIs 103 and 107 , the actual arm lengths are L+ΔL and L and in MZI the actual arm lengths are L+2ΔL and L. Thus, the signal path from one output port of y-branch coupler 102 to the output port 109 of y-branch coupler 108 follows a path of length L+ΔL through MZI 103 , L through MZI 105 , and L+ΔL through MZI 107 , giving a total length of 3L+2ΔL; and the other path consists of L, L+2ΔL, and L, also giving a total length of 3L+2ΔL. Thus for the zero dispersion setting, the TDC device acts simply as a waveguide of length 3L+2ΔL and so introduces no significant chromatic dispersion.
In the above description ΔL determines the free spectral range (FSR) of the TDC. The FSR is equal to
FSR=C 0 /ΔL·n g
Where
C 0 is 300 km/s (vacuum speed of light)
n g is the group refractive index of the MZI waveguides.
In one illustrative design, for an optical signal data rate of 10 Gb/s, the FSR would be about 25-GHz. Such an MZI-based TDC with a 25-GHz-free-spectral-range version can compensate ˜±2100 ps/nm for 10 Gb/s signals. In a multi-wavelength channel system, having a FSR equal to the system wavelength channel spacing divided by an integer makes it possible for the TDC to compensate many channels simultaneously. Thus, my TDC is colorless, i.e., it can compensate many channels simultaneously or be selectable to compensate any channel in a multi-wavelength channel system
In a well-known manner, MZIs 103 , 105 , 107 may be implemented together as a planar optical integrated circuit or may be implemented using discrete optical elements mounted on a substrate.
The dispersion of TDC can be tuned positive or negative by adjusting couplers 104 and 106 toward 50/50 using a control signal C 1 . As will be discussed with reference to FIG. 3 , by selecting a control signal C 1 that is higher or lower that the zero dispersion control signal C 1 setting, TDC can be set to a positive or negative dispersion level. The design is similar to the birefringent crystal design of Ref. [9], except that the device of [9] was not tunable, using only a fixed 50/50 coupling ratio. Advantageously, my TDC design is colorless, i.e., it can compensate many channels simultaneously or be selectable to compensate any channel in the system.
Note that while the adjustable couplers 104 and 106 are controlled by a common control signal C 1 , if desirable separate control signals may be used. Separate controls could be useful, for example, if the couplers have unequal characteristics due to fabrication non-uniformities.
FIG. 2 illustrates, in accordance with the present invention, a TDC of FIG. 1 where the adjustable couplers 104 and 106 are implemented using two MZI-based adjustable couplers. As shown, the adjustable couplers 104 , 106 are implemented using small MZIs with controllable phase shifters. Each MZI includes a 50/50 fixed evanescent coupler 201 , upper phase shifter 202 , lower phase shifter 203 , and 50/50 fixed evanescent coupler 204 . Driving both the lower phase shifters 203 of both MZIs with the same control signal C 1 at a first level pushes the dispersion in one direction, and driving both upper phase shifters 202 at a second level pushes the dispersion in the other direction. Depending on the orientations of the main MZIs, there may be a small path-length difference between the two arms in the adjustable coupler MZI.
If the phase shifters 202 , 203 are thermooptic heaters, then a convenient electrical layout that requires only one control signal C 1 is shown in FIG. 3 . The control signal C 1 voltage is varied between the levels V 1 and V 2 , where V 2 is greater than V 1 . When control voltage C 1 is at a predetermined zero dispersion level Vz between V 1 and V 2 , then the same current flows through both the upper and lower phase shifters establishing zero dispersion and, hence, adjustable couplers 202 , 203 perform a simple cross-connect function as discussed previously. When control signal C 1 is at level V 1 then no current flows through the upper phase shifters 202 and current flows through the lower phase shifters 203 establishing the maximum amount of a dispersion of a first polarity. When the desired dispersion level is somewhere between zero dispersion level Vz and the maximum first polarity dispersion level V 1 , then control signal C 1 is suitably adjusted to a voltage level between V 1 and Vz. At control signal C 1 levels between V 1 and Vz, the upper 202 and lower 203 phase shifters are operated in a push-pull arrangement. That is, for example, in the upper phase shifter 202 current is increasing while in the lower phase shifter current is decreasing.
When control signal C 1 is at level V 2 then no current flows through the lower phase shifters 202 and current flows through the upper phase shifters 203 establishing the maximum amount of a dispersion of a second polarity. When the desired dispersion level is somewhere between zero dispersion level Vz and the maximum second polarity dispersion level V 2 , then control signal C 1 is suitably adjusted to a voltage level between Vz and V 2 . This push-pull operation of the upper 202 and lower 203 phase shifters results in a low worst-case thermooptic power consumption and roughly constant power dissipation for all tuning settings [10].
With reference to FIG. 4 there is shown, in accordance with the present invention, a reflective design of a tunable dispersion compensator (TDC) that also uses only one control voltage. Since the TDC arrangement of FIG. 1 is symmetric, as shown in FIG. 4 it can be implemented using a simpler reflective design, at the expense of requiring a circulator. In the reflective design of FIG. 4 , MZI 403 performs the function of the first 103 and third 107 MZIs of FIG. 1 and reflective MZI 405 performs the function of MZI 105 of FIG. 1 .
An input optical signal at port 400 passes through circulator 401 and is split equally to the two arms of the MZI 403 by the y-branch coupler 412 . In the MZI 403 , one arm is longer, by ΔL, than the other arm so that when the optical signals are recombined in the first adjustable coupler 404 , the amount of light sent to each of the two arms of the reflective MZI 405 depends on the wavelength. The adjustable coupler 404 operates in response to a control signal C 1 that controls both the sign and amount of dispersion introduced to the signals outputted from the coupler 404 to the arms 407 , 408 of the reflective MZI 405 and also establishes the same sign and amount of dispersion introduced to the signals outputted from the coupler 404 to the arms of MZI 403 . Note that the reflective MZI 405 has a reflective facet 406 for reflecting signals received from the two arms 407 and 408 back to these arms. Since the signal traverses twice through arms 407 , 408 , both left-to-right and then right-to-left, the length of arm 407 is need only be ΔL longer than arm 408 . The reflected signals then traverse MZI 403 in the right-to-left direction (to act like MZI 107 of FIG. 1 ) and are combined in y-branch coupler 402 (which acts like y-branch coupler 108 of FIG. 1 ). The output signal from y-branch coupler 402 then passes through circulator 401 to output port 409 . Reflective TDC of FIG. 4 , using control signal C 1 , can control the sign and amount of dispersion introduced to the signal outputted from output port 409 in the same manner that is achieved by TDC of FIG. 1 .
Note that one can create an adjustable coupler by other methods than as shown in FIG. 2 . For example, instead of two 50/50 evanescent couplers 201 and 204 one can use two 50/50 multi-section evanescent couplers. Multi-section evanescent couplers can give a more accurate 50/50 splitting ratio in the face of wavelength, polarization, and fabrication changes. Another possibility is to use multimode interference couplers.
Likewise, couplers 102 and 108 could be other 50/50 couplers than y-branch couplers. For instance, they could be multimode interference couplers.
FIG. 5A shows the simulated transmissivity and FIG. 5B shows chromatic dispersion (group delay characteristic) through my TDC at three different settings (0, +π/2, −π/2) of the adjustable couplers (s) of FIGS. 1 and 4 . In FIGS. 5A and 5B , the free-spectral range is 25 GHz, at the limits and center of the tuning range. The wavelength is 1550 nm. The marked phases denote the phase difference between the MZI arms in the tunable couplers of FIG. 2 . The loss is theoretically zero and does not increase at the channel center as the dispersion is tuned away from zero. At maximum dispersion, there is a transmissivity ripple of 1.25 dB peak-to-peak; the dispersion reaches ±2500 ps/nm. The bandwidth is not very wide, though: the transmitter frequency error must be less than ˜±2.5 GHz (±20 pm). This is achievable for wavelength-locked transmitters. Practically, for 10 Gb/s signals in this case the dispersion is limited to ˜±2100 ps/nm
FIGS. 6A and 6B show the use of my TDC in illustrative optical transmission systems. FIG. 6A shows a pre-transmission dispersion compensation system where the first location 600 includes an optical transmitter unit 601 , a TDC 602 used for pre-transmission dispersion compensation, an optical amplifier 603 , and a wavelength multiplexer 604 , if needed. The output signal is sent over the optical facility 610 to a second location 620 that includes a wavelength demultiplexer 621 (if needed), an amplifier 623 , and an optical receiver unit 622 . Since the illustrative optical transmission systems is bi-directional, the first location also includes a demultiplexer 621 (if needed), an amplifier 623 , and an optical receiver unit 622 connected over optical facility 630 to the second location 620 which includes an optical transmitter unit 601 , a TDC 602 used for pre-transmission dispersion compensation, an optical amplifier 603 , and a multiplexer 604 (if needed). Note that the optical transmitter unit 601 and the optical receiver unit 622 are typically packaged together as a transponder unit 640 .
FIG. 6B shows a post-transmission dispersion compensation system where the first location 600 includes an optical transmitter unit 601 , an optical amplifier 603 , and a wavelength multiplexer 604 (if needed). The output signal is sent over the optical facility 610 to a second location 620 that includes a wavelength demultiplexer 621 (if needed), an amplifier 623 , a TDC 602 for post-transmission dispersion compensation, an optical filter 605 [e.g., an amplified spontaneous emission (ASE) filter], and an optical receiver unit 622 . Since the illustrative optical transmission systems is bi-directional, the first location also includes a demultiplexer 621 (if needed), an amplifier 623 , a TDC 602 , an optical filter 605 , and an optical receiver unit 622 connected over optical facility 630 to the second location 620 which includes an optical transmitter unit 601 , an optical amplifier 603 , and a multiplexer 604 (if needed). The order of the TDC 602 and ASE filter 605 could be reversed without affecting system performance.
Note that for a system having a standard single mode fiber (SSMF) optical facility 610 less than about 80 Km, no dispersion compensation is typically needed. For a SSMF optical facility 610 in the range of about 80-135 Km the pre-transmission dispersion compensation system of FIG. 6A is preferable. For a SSMF optical facility 610 in the range of about 135-160 Km the pre-transmission dispersion compensation system of FIG. 6B is preferable.
In the system arrangements of FIGS. 6A and 6B , it should be noted that TDC 602 can be integrated together with one or more of the optical components, such as optical transmitter 601 , optical amplifier 603 , optical filter 605 , wavelength multiplexer 604 , wavelength demultiplexer 621 , and optical receiver 622 . For example, the TDC could be monolithically integrated in InGaAsP with a laser and an optical modulator to form an optical transmitter with built-in dispersion precompensation.
FIG. 7A shows on illustrative design of my TDC arranged together with an Erbium amplifier. In this arrangement, the TDC 700 is arranged in a polarization diversity scheme, in order to make the TDC function polarization independent even if the TDC device itself is polarization dependent, in which polarization-maintaining fibers (PMFs) 702 and 703 are spliced to a circulator/polarization splitter (CPS) 701 of the type described in Ref. [11]. In operation, an input optical signal 700 received by the circulator is split in the polarization splitter and coupled via PMF 702 to TDC 700 . The dispersion compensated optical signal from TDC 700 is coupled via PMF 703 to polarization splitter and the circulator to Erbium amplifier 710 . The circulator/polarization splitter (CPS) 701 eliminates the need for an input signal isolator 711 in Erbium amplifier 710 . Thus, the Erbium amplifier 710 need only include the Erbium fiber output isolator 713 and either forward pump and coupler 714 or back pump and coupler 714 . It should be noted that since the TDC of FIG. 1 has only three stages, it can relatively simply be made polarization independent on its own and therefore does not need the polarization diversity scheme using PMFs 702 and 703 and circulator/polarization splitter (CPS) 701 .
FIG. 7B shows a polarization independent reflective TDC 751 of FIG. 4 arranged together with Erbium amplifier 710 . A circulator 750 is used to couple the input optical signal 700 to TDC 751 and to couple the dispersion compensated optical signal to Erbium amplifier 710 .
With reference to FIG. 1 , I illustratively describe the initial setup of an exemplary prototype TDC that was made and tested. The TDC was temperature controlled with a thermoelectric cooler. Because the path-length differences in MZIs 103 , 105 , and 107 are so large, after fabrication the relative phase in each MZI stage was random. Thus the arms are permanently trimmed using hyper-heating [12 ]. The procedure is as follows: with no power applied, the adjustable couplers 104 , 106 are set for 100/0 (i.e., the couplers look like waveguide crossings in FIG. 1 ), and the transmissivity spectrum is flat. Then the left coupler 104 is adjusted to be 0/100, causing the transmissivity spectrum to have a full sinusoidal ripple. The position of a valley is marked. Then the left coupler 104 is restored to 0/100, and the right coupler 106 adjusted to 0/100. The path-length differences in the two outermost MZIs 103 , 107 are correct when the ripples from the two cases are wavelength-aligned. If they are not, one of the outer MZIs' arms is hyperheated to make them aligned. Then, with both couplers 104 , 106 at 100/0, the center MZI 105 arms are hyperheated in order to maximize the transmissivity. After trimming, the fiber-to-fiber loss of the TDC apparatus, including the CPS, is 4.0 dB.
Various modifications of this invention will occur to those skilled in the art. Nevertheless all deviations from the specific teachings of this specification that basically rely upon the principles and their equivalents through which the art has been advanced are properly considered within the scope of the invention as described and claimed.
REFERENCES
[1] C. K. Madsen, G. Lenz, A. J. Bruce, M. A. Cappuzzo, L. T. Gomez, and R. E. Scotti, “Integrated all-pass filters for tunable dispersion and dispersion slope compensation,” IEEE Photon. Technol. Lett., vol. 11, pp. 1623-1625, December 1999.
[2] M. Shirasaki, “Chromatic dispersion compensator using virtually imaged phased array,” IEEE Photon. Technol. Lett., vol. 9, pp. 1598-1600, December 1997.
[3] Koichi Takiguchi, Kaname Jinguji, Katsunari Okamoto, and Yasuji Ohmori, “Variable group-delay dispersion equalizer using lattice-form programmable optical filter on planar lightwave circuit,” IEEE J. Sel. Topics in Quant. Electron., vol. 2., pp. 270-276, 1996.
[4] M. Bohn, F. Horst, B. J. Offrein, G. L. Bona, E. Meissner, and W. Rosenkranz, “Tunable dispersion compensation in a 40 Gb/s system using a compact FIR lattice filter in SiON technology,” European Conference on Optical Communication, paper 4.2.3, 2002.
[5] S. Suzuki, T. Takiguchi, and T. Shibata, “Low-loss integrated-optic dynamic chromatic dispersion compensators using lattice-form planar lightwave circuits,” in Optical Fiber Communication Conf. Digest, pp. 176-177, 2003.
[6] D. J. Moss, M. Lamont, S. McLaughlin, G. Randall, P. Colboume, S. Kiran, and C. A. Hulse, “Tunable dispersion and dispersion slope compensators for 10 Gb/s using all-pass multicavity etalons,” IEEE Photon. Technol. Lett., vol. 15, pp. 730-732, May 2003.
[7] C. R. Doerr, L. W. Stulz, S. Chandrasekhar, L. Buhl, and R. Pafchek, “Multichannel integrated tunable dispersion compensator employing a thermooptic lens,” Optical Fiber Communication Conference, postdeadline paper FA6-1, 2002.
[8] D. Nielson, R. Ryf, D. Marom, S. Chandrasekhar, F. Pardo, V. Aksyuk, M. Simon, and D. Lopez, “Channelized dispersion compensator with flat pass bands using an array of deformable MEMS mirrors,” OFC postdeadline paper PD29, 2003.
[9] T. Ozeki, “Optical equalizers,” Opt. Lett., vol. 17, pp. 375-377, March 1992.
[10] C. R. Doerr, L. W. Stulz, R. Pafchek, and S. Shunk, “Compact and low-loss manner of waveguide grating router passband flattening and demonstration in a 64-channel blocker/multiplexer,” IEEE Photon. Technol. Lett., vol. 14, pp. 56-58, January 2002.
[11] C. R. Doerr, K. W. Chang, L. W. Stulz, R. Pafchek, Q. Guo, L. Buhl, L. Gomez, M. Cappuzzo, and G. Bogert, “Arrayed waveguide dynamic gain equalization filter with reduced insertion loss and increased dynamic range,” IEEE Photon. Technol. Lett., vol. 13., pp. 329-331, April 2001.
[12] K. Moriwaki, M. Abe, Y. Inoue, M. Okuno, and Y. Ohmori, “New silica-based 8×8 thermo-optic matrix switch on Si that requires no bias power,” in Optical Fiber Conf. Digest, pp. 211-212, 1995. | A method and apparatus for implementing a new type of colorless Mach-Zehnder-interferometer (MZI)-based tunable dispersion compensator (TDC) that has only three MZI stages (two in a reflective version) and two adjustable couplers which are responsive to one control voltage, making it compact, low power, and simple to fabricate, test, and operate. | 6 |
BACKGROUND OF INVENTION
The present invention relates to an apparatus useful for application of sheet material, especially self-adhesive, waterproofing sheet material. More particularly, the present invention relates to an apparatus whereby a roll of waterproofing sheet material can be readily placed on a substructure surface in an accurate manner and by a one-man operation.
Various types of sheet material are used in forming a waterproof roof or other substructure system. Included among such materials are bituminous impregnated sheet material commonly known as tar paper or felt. More recently, preformed, flexible, sheet-like membranes of waterproofing, pressure-sensitive adhesives such as are disclosed in U.S. Pat. Nos. 3,741,856; 3,853,683 and 3,900,102 have been formed. Each of these materials must be applied to the roof substructure in an accurate manner to insure complete abutment or, preferably, overlap of the successively applied layers. Normally such an operation is laborious, requiring an extensive amount of stooping, bending and the like, and at least two persons to attain accurate application.
Various types of apparatus have been devised for the application of roofing material or other stock material from storage rolls. U.S. Pat. Nos. 2,439,681 and 3,559,914 disclose such apparatus. These prior art apparatus have not found general acceptance because they are of complex design, are not capable of being operated by one person and do not permit change of direction during application of a single course of roofing material.
The presently described applicator permits easy application of rolls of tar paper, bituminous impregnated felt products and most especially, preformed waterproofing, pressure-sensitive adhesive sheet material used to cause waterproofing of various substructures such as roofs. The utilization of the subject applicator shall be described in relation to the application of a waterproofing, pressure-sensitive adhesive sheet material. The application of other rolled stock material onto substructures can also be readily performed in manners which will be obvious from the present teaching.
SUMMARY OF THE INVENTION
The subject invention is directed to a simple, yet effective one-man operable apparatus for application of sheet material and the like in roll form. The apparatus comprises a U-shaped body of continuous length having a handle portion and a pair of leg portions extending from the opposite ends of the handle portion. The free end of each leg portion has a mounting means connected thereto. The mounting means of each leg portion is perpendicularly connected to the respective leg portion and is in facing relationship with the other mounting means. The subject applicator further comprises a rigid, stabilizing member positioned between the leg portions and having, at the opposite free ends of said stabilizing member a slidable constraining means whereby the stabilizing member is slidable axially along the leg members in substantially parallel attitude with respect to said handle portion. The constraining means further permits the leg portions to be sprung outwardly and apart when the stabilizer member is close to the handle portion of the body and to be forced inwardly when in a predetermined closely spaced relationship to the free ends of the leg portions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an applicator apparatus according to a preferred embodiment of the present invention.
FIG. 2 is a sectional view of the stabilizing bar and slidable mounting of the applicator apparatus of FIG. 1 as taken along lines 2--2 therein.
FIG. 3 is a sectional view of the stabilizing bar, slidable mounting and leg portion of the body member shown in FIG. 2 as taken along line 3--3 therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Rolls of preformed, waterproofing, pressure-sensitive adhesive sheet material are generally applied by unrolling the material onto a roof or other substructure so that the adhesive membrane is adjacent to the substructure and its polymeric support membrane is on the resultant exposed side. Although the adhesive properties of the membrane enhance its waterproofing ability, they normally detract from its being readily applied in an accurate manner over long courses. Further, the adhesiveness and bulk of such material causes extensive twisting or torque forces to be exerted on the applicator when attempting even slight changes of direction of application. Such torque forces normally cause loss of control of the roll of material.
The present applicator permits a simple mode of application of such normally difficult-to-apply waterproofing material with accurate and correct alignment on a substructure. Further, the present applicator readily permits one-man application of such normally difficult-to-apply material. Finally, the present applicator securely holds the roll of roofing material under varying torque or twisting forces produced during the guidance and change of direction of application such as are especially incurred when applying adhesive membrane roofing material.
Referring to FIG. 1, there is illustrated an applicator apparatus 1 for applying rolls of sheet roofing material 12. The applicator body 2 is expediently made from metal rod or tubular material bent into a modified U-shape configuration to form a handle portion 3 and leg portions 4 and 4'. One end of each of the leg sections 4 and 4' is integrally connected at 5 and 5' with the opposite ends of handle portion 3. Each of the leg portions is slightly sprung in an outward manner, that is, the distance between the free ends 6 and 6' of leg portions 4 and 4' is greater than the distance between connections 5 and 5'. The applicator body can alternatively be formed from sections of metal rod or tubular material by securely connecting, such as by welding or equivalent means, the sections so as to form the desired integral configuration. The opposite free ends 6 and 6' of leg portions 4 and 4', respectively, have perpendicularly connected thereto mounting means 7 and 7'. Each of the mounting means is in face-to-face relationship with the other and comprises a chuck in the form of a cylindrical member 8 which extends axially along an imaginary line 11 connecting the free ends 6 and 6' of each leg portion 4 and 4'. The radius of the cylindrical member 8 should be substantially that of the inside radius of a standard cylindrical core (not shown) upon which the conventional sheet material is wound and shipped.
To aid in mounting the roll of roofing material on the chuck, it is preferable that the radius of cylindrical member 8 become smaller in direct relationship to the distance from the leg section to which the mounting means is connected. The mounting means may further comprise a collar member 9 having a radius extending outwardly from axis 11 which is greater than the radius of the cylindrical core of the roofing material and thereby aids in holding the roll of roofing material in its mounted position. Members 8 and 9 can be formed from any durable material such as wood, metal or plastic. Each mounting means further comprises a connector rod 10 to connect the cylindrical chuck 8 and collar 9 to the free end of a leg section. The connector rods 10 are connected to cylindrical chucks 8 or cylindrical collar member 9 in a manner to permit rotation of members 8 and 9 about axis 11 to facilitate the rotation of the roll of roofing material when being applied to the substructure as described hereinbelow.
The apparatus of the present invention further comprises a stabilizing means 15 which is located between leg portions 4 and 4' and is in the form of a rigid bar. The opposite ends of stabilizing bar 15 are each connected to leg sections 4 and 4' by slidable constraining means 16 and 16', respectively. The constraining means 16 and 16' are rigid members circumventing around each of the respective leg portions 4 and 4', and in slidable relationship therewith.
The stabilizing bar 15 is capable of axial movement via the constraining means along the leg portions in a manner which requires the stabilizing bar to be in substantially parallel attitude with respect to the handle portion 3. The movement of the stabilizing bar 15 is further limited to between special positions of close or adjacent to the handle portion 3 and of a predetermined lower position (close to the leg portion free ends) which is defined by a collar or other stoppage means.
Each leg section 4 and 4' has connected thereto a stop means 14 such as in the form of a collar extending radially outwardly from the leg section. Each stop means 14 is connected to the leg section at a point from the leg section's free end 6 of at least greater than the radius of a standard full roll of roofing material to about a distance of one-third of the leg section. The stop means arrests the downward movement and supports, at its lowest position, the stabilizing bar and its associated constraining mounting means as described hereinbelow.
Mounted on each leg section 4 and 4' in the neighborhood of the free ends 6 and 6', respectively, is a support means 13 which is shown in the form of a rocker stand member. Each support means 13 is mounted on a leg section substantially perpendicular to the axis line 11, at a right or oblique angle with the leg section 4 and extending in an outward radial direction a distance greater than the radius of a standard full roll of roofing material.
FIG. 2 shows a detailed view of a preferred slidable constraining means 16 and its relationship with the stabilizing bar 15, stop means 14 and leg portion 4. The same relationship exists with respect to leg portion 4'. Rigid stabilizing bar 15 has its end connected at 18 to rigid plate members 17 and 17'. Plate members 17 and 17' are parallel to and spaced from one another at a distance slightly greater than the diameter or width of leg section 4. The clearance 19 should be sufficient to allow free slidable movement of the plate members 17 and 17' along leg section 4. The distance between the plates should not be greater than about 1.5 times the radius of the leg section 4. Plate members 17 and 17' are to be a length sufficient to extend beyond and to have a member connecting the plates exterior to the outer portion of the leg portion 4. The connecting member is shown as a guide roller 20 mounted on axle pin 21 between plates 17 and 17' at a point outside of body 2. The opposite ends of pin 21 are connected to plates 17 and 17' substantially perpendicular thereto. Further, a guide roller 22 and its axle pin 23 are located between plates 17 and 17' at a point between leg portion 4 and stabilizing bar 15. The axle pin 23 is connected to plates 17 and 17' and substantially perpendicular thereto.
FIG. 3 is a cross-sectional view of constraining means 16, and illustrates the interrelationship of the stabilizing bar 15, the parts of the illustrated preferred constraining means 16, leg portion 4 and stop means 14. The leg portion 4 of the applicator body 2 has mounted thereon a stop means 14 which is shown in the form of a collar 24 and support sleeve 25. The collar 24 extends radially outwardly from leg 4 at a distance such that plates 17 and 17' of constraining means 16 rest thereon and are stopped thereby from going to a lower position with respect to leg 4. As stated hereinabove, leg 4 is part of applicator body 2 which is in a modified U-shape, that is, the leg members are sprung slightly outwardly from center. When the stabilizer bar is in the lower position, i.e., adjacent to stop means 14, the outer guide roller 20 and its counterpart on the opposite guide 16' are at a distance from each other so as to guide the leg sections of body 2 inwardly a distance to permit mounting means 7 and 7' to be inserted into the core (not shown) of the roll of sheeting material 12. In this position the interaction of the rigid bar 15 and the constraining means 16 causes a stabilization of the applicator against varying torque forces and the like, secures the mounting of the roll of sheet material and permits the one-man application of the sheet material on a substructure surface in an accurate manner. When stabilizing bar 15 is moved into an upper position, i.e., adjacent to handle 3, guide rollers 20 and 22 aid in guiding the movement without causing binding between leg 4 and mounting means 16.
The subject applicator has been found to permit easy, accurate, one-man application of roofing material. The applicator has been found to be especially useful in the application of adhesive, waterproofing bituminous sheet compositions, and such application will be discussed herein to illustrate the usefulness of the present applicator.
Waterproofing pressure-sensitive sheet compositions must be accurately laid to cause complete butting of the edges or a certain degree of overlap (depending on the type of material used) to form a watertight joint between adjacent courses of the laid sheet material. The body 2 of the present applicator is placed in a substantially horizontal position permitting supports 13 to raise the mounting members 7 above horizontal to aid in mounting the roll of roofing material 12 onto members 7. The stabilizing bar 15 is positioned adjacent to handle 3 to permit leg portions 4 and 4' to be sprung sufficiently outwardly to readily permit the mounting of the roll 12 onto mounting means 7 and 7'. Stabilizing bar 15 is then moved to its lower position, i.e., against stop 14, thus causing guide rollers 20 to force legs 4 and 4' to move inwardly and to cause the chucks of mounting means 7 and 7' to be substantially inserted and maintained in the core of sheet material 12.
The roll of waterproofing material, comprising a sheet of adhesive bituminous composition laminated with a support sheet, should be positioned on the applicator so that the adhesive bituminous composition is directly applied to the substructure when the applicator/roofing roll is rolled in a direction towards the support members 13. The body 2 of applicator 1 is raised to a position suitable for handling by the user and tilted away from the side of the support members 13. The stabilizing bar 15 and its accompanying slidable mounting means are held in the lower position by the force of gravity and by constraining means 16.
The roll of material 12 can be readily applied to a substructure by a single individual pushing the roll 12 along the desired course to deposit the sheet material 12' on the substructure. The adhesive properties of this waterproofing sheet material readily adhere to the substructure via the pressure exerted on it by the unconsumed roll. Changes and corrections of direction of application can be readily accomplished without loss of control of the roll of unused materials due to the unexpected rigidity and strength given to the applicator structure through the stabilizer bar and the constraining means associated therewith.
From the foregoing description it can be appreciated that the applicator of the present invention is adaptable to numerous variations and modifications to suit the needs of specific applications and while being described in connection with waterproofing sheet-like bituminous roofing material it can be used for application of other similar materials and for application of such materials to other substructures. | An applicator suitable for one-man application of sheet material in an accurate manner onto structural substrates wherein the applicator can direct changes in the path of application while readily maintaining control over the roll of sheet material. | 4 |
The present invention relates to concrete structures. An object of the invention is to provide a concrete structure suitable for constituting a ballastable base for an offshore platform.
Another object of the invention is to provide a concrete structure suitable for constituting a weight-carrying three-dimensional lattice.
BACKGROUND OF THE INVENTION
Ballastable concrete bases for offshore platforms are known which are constituted by solid concrete walls. These bases may be suitable for use in cold seas since they are strong enough to resist the pressure of ice, which may be very high, but they suffer from the drawback of being very heavy. Attempts have been made to lighten them by using lightweight concrete, but this solution is expensive and not entirely satisfactory.
Preferred embodiments of the present invention provide a base which may be made from normal concrete, which has high strength, and which is nevertheless of reasonable weight.
SUMMARY OF THE INVENTION
The base of the present invention is essentially constituted by a volume formed from a rigid three-dimensional lattice of concrete bars which are assembled in concrete nodes, some of the nodes being interconnected by cables which pass outside the bars and which may pass intermediate nodes, said cables providing three-dimensional prestressing for the lattice assembly as a whole, the base including means for making waterproof the sides and the bottom of the lattice.
The concept of a three-dimensional concrete lattice is known, but up to the present, such a lattice has not been used for the specific application outlined above in combination with prestressing cables for the lattice as a whole and in combination with waterproof sides and bottom.
Further, up to the present, there has not been a known industrial technique enabling a concrete lattice to be made under acceptable conditions, and one aim of the invention is also to provide such a technique and to apply it not only to the fabrication of a platform base, but also to any other structure.
In accordance with the invention, the lattice is constituted from an assembly of blocks which are prefabricated by molding, each block comprising a node and a plurality of arms radiating from the node, each arm having at least one longitudinal socket open at the free end of the arm, with arms being assembled in aligned pairs to constitute the bars of the lattice, the sockets of an assembled pair of arms being aligned and receiving a common metal reinforcing member, the junction zone between the assembled arms being surrounded by a sealing sleeve, the said sockets being filled with hardened mortar, and the said lattice being clamped by prestress cables which pass outside the bars of the lattice and which are fixed to same nodes of the lattice.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described by way of example with reference to the accompanying drawings, in which:
FIG. 1 is a vertical half-section through a platform base in accordance with the invention;
FIG. 2 is a set of horizontal sections through the base on planes at different levels;
FIG. 3 is a perspective view of a component block for the base lattice;
FIG. 4 is a diagram showing how two portions of a bar are assembled to build up a bar of the lattice.
FIG. 5 is a diagram of a bottom pyramid of the base;
FIG. 6 is a diagram of a portion of the lateral facade of the base;
FIG. 7 is a perspective view of another embodiment of a prefabricated block and of a portion of a base built up for such blocks;
FIG. 8 is a perspective view of a further embodiment of a prefabricated block in accordance with the invention;
FIG. 9 is a perspective view of a portion of the base in accordance with a variant of the invention and on which a portion of the facade has been shown; and
FIG. 10 is a diagram of prestress cables of the base.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The platform base shown in FIGS. 1 and 2 is a hexagonal base having a side of 72 meters (m). The base is constituted by a lattice which is provided with means for making watertight the lateral sides and the bottom of the lattice. In accordance with the invention, the lattice is constituted by concrete bars which are assembled at concrete nodes. The sides and the bottom of the lattice are provided with walls for making them watertight.
In a preferred embodiment, the lattice is an assembly of regular tetrahedra, with the nodes being constituted by the vertices of the tetrahedra and the bars being disposed along the sides of the tetrahedra.
In this assemby of tetrahedra, there are inclined planes in which the bars form a mosaic of equilateral triangles and inclined planes in which the bars form a mosaic of squares or rectangles. There are also horizontal planes in which the bars form a mosaic of equailateral triangles.
In the embodiment, shown the bars of the lattice form squares in planes inclined at 50° to 60°, they form equilateral triangles in planes inclined at 65° to 75°, and they form equilateral triangles in horizontal planes.
Preferably, the lateral sides of the lattice comprise planes in which the bars form equilateral or isoscele triangles alternating with planes in which the bars for squares or rectangles.
The plane of the section of FIG. 1 is a vertical plane and the figure shows one half of the section plane.
FIG. 2 shows a plurality of horizontal section planes. FIG. 2 is thus divided into six portions each representing a fraction of a horizontal section at a different level. For example, reference numerals 1, 2, 3, 4, 5, and 6 represent sections at levels which are approximately at 0 m, 5 m, 10 m, 15 m, 20 m, and 25 m respectively. In the fraction of the figure representing the 0 m level section plane, it can be seen that the bottom plane of the lattice is constituted by a mosaic of equilateral triangles A, B, C whose sides are constituted by bars of the lattice and whose vertices are constituted by nodes of the lattice. A part of the fraction of the figure relating to the level of about +5 m, is shaded to show the portion of the lateral facade which extends below the plane of the section. Similar shading is to be found on the fractions representing sections at about +10 m and at about +25 m.
The section of FIG. 1 is taken on a plane marked A--A in FIG. 2.
The lattice may be made by any suitable method, but is preferably made by the following method.
In this technique in accordance with the invention, blocks are injection molded in closed molds, which blocks comprise a central node and arms which radiate from the node. The node is intended to become one of the nodes of the lattice, and each arm is intended to constitute a portion of a lattice bar.
The arms are assembled in pairs with an arm from one block being disposed end-to-end with an arm from another block thereby constituting one bar of the lattice. The lattice is built up piece-by-piece in this manner. In a preferred embodiment, a portion of the bottom level of the lattice is made first, then the next level portion, and so on up to the top level portion, with block positioning devices running on the ground just ahead of where assembly is being performed. Each level is thus built up piece-by-piece.
It may be observed that the blocks may be prefabricated in a workshop, which is particularly advantageous for ballastable offshore platforms which usually have to be built in dry dock.
The invention enables a large portion of the work to be performed away from the dry dock, since only the actual assembly of the blocks needs to be done in the dry dock.
Any suitable means may be used to assemble two arms, and preferably the arms are prefabricated with respective sockets with openings in their end faces which coincide when the arms are placed end-to-end. Each socket is additionally provided with a passage enabling mortar to be inserted therein or enabling air to be evacuated therefrom. For assembly, a common reinforcing member is placed in the two sockets, a sealing sleeve is placed around the junction between the two arms and mortar is inserted into the sockets and is allowed to set therein.
The sleeve is preferably made of heatshrink material.
It may be observed that the mortar which fills the sockets may constitute a pad of greater or lesser thickness between the end faces of the arms. The position of each new node to be added to the structure can thus be accurately adjusted by injecting mortar to move the end faces of the arms apart, jacklike. The mortar then sets leaving a pad J of just the wanted thickness. It is thus easy to ensure that each node is correctly positioned during assembly, and this constitutes an important advantage of the method of the invention.
FIG. 4 is a diagram for explaining the technique of assembling two arms, as described above. In this diagram the arms are referenced 14 and 14', the corresponding nodes 15 and 15', the corresponding sockets 16 and 16', their passages 17 and 17', the sleeve is referenced 18 and the reinforcing member 19.
In a typical example, the arms are rods having a right cross section that can be inscribed in a circle of 20 cm to 100 cm diameter, and the bars are 2 m to 10 m long. The rods are preferably of circular section with a diameter in the range 30 cm to 80 cm, and the bars are preferably assembled using a mortar capable of withstanding high compression at pressures of up to 600 to 1000 bars.
Each arm preferably constitutes one half of a bar.
This preferred choice is not essential, and the arms could constitute fractions other one half of a bar in variant embodiments, however, the choice of one half makes for highly rationalized construction.
Further, two arms could be interconnected by an intermediate member rather than being directly interconnected. For example, if each arm constitutes one third of a bar, two arms would be interconnected by means of an intermediate member constituting the middle third of the bar.
The overall lattice is clamped by cables which provide three-dimensional prestressing. The cables are fixed at their ends to nodes of the lattice.
In a typical example, a given cable will repeatedly pass lattice bars which it crosses substantially in the middle and orthogonally, interspersed by lattice nodes which it also passes.
FIG. 3 is a perspective view of a single block given by way of example and constituting a node 1 from which 12 arms (2-13) radiate, which each arm being intended to constitute one half of a lattice bar.
Thus, in the lattice of FIGS. 1 and 2, there are eight-arm blocks, nine-arm blocks and twelve-arm blocks.
Naturally, it will readily be understood that the blocks situated in the outside planes of the lattice, ie. in the planes which constitute the bottom, the sides and the top of the lattice, have fewer arms.
The base is additionally provided with a watertight bottom and with a watertight facade.
The watertight bottom is preferably constituted by a mosaic of pyramids thus enabling the bottom to penetrate as far as required into the adjacent subsoil beneath the final position of the platform.
FIG. 5 is a perspective view of a pyramid component in one of the lattice tetrahedra.
The pyramid and the tetrahedron have a common base DEF, but the vertex G of the tetrahedron is above the vertex H of the pyramid. To construct the pyramid, it is convenient to have a portion of each face of the pyramid molded integrally with the corresponding node of the lattice. For example, one half of the face DHE should be molded with the node D, while the other half should be molded with the node E.
The two halves are then assembled by any suitable technique, eg. by a technique similar to that used to assemble two arms end-to-end to form a bar.
Thus the pyramids at the bottom of the base are installed at the same time as the nodes which constitute the bottom level of the lattice.
The facade of the base is preferably a corrugated concrete facade. To make the facade (see FIG. 6), is it convenient to prefabricate elongate concrete troughs each comprising two plane walls P1 and P2 at an angle to each other, and then to fix the troughs to the outside bars of the lattice to build up the facade. It is thus advantageous for the outside bars of the lattice to constitute rectangles extending upwards along the outside face of the lattice with the plane walls P1 and P2 being fixed in watertight manner to the bars b situated along the long sides of the rectangles and so forth from trough to trough.
FIGS. 7 to 10 show variant embodiments of the invention.
In FIG. 7, the molded block is constituted by a central spherical node 15 with cylindrical arms 14 radiating therefrom. To the left of the block there is a portion of assembled lattice built up from similar blocks, and sleeves 18 can be seen on the arms of the blocks in end-to-end pairs to constitute the bars of the lattice.
FIG. 8 is a perspective view of another variant of a lattice block.
FIG. 9 is a perspective view of a portion of a lattice. The bars of the lattice in the planes underlying the facade are disposed along the sides of squares Q and along the sides of triangles T, which may outline trapeziums. These dispositions are not limiting and are given merely by way of example. FIG. 9 also shows a portion of the lateral facade. In this example, the lateral facade is built up from portions of facade that correspond in size to and that are fixed to one of the tetrahedra of the lattice, and the different portions of the facade are successively joined together by mortar or by added on concrete.
FIG. 10 is a simplified view showing schematically two prestress cables 20,21. Prestress cable 20 is rectilinear and its ends are fixed to two nodes 22,23 of the lattice.
The cable crosses several bars of the lattice such as bars 24 and 25 but remains outside the bars. Prestress cable 21 also is attached at both ends at nodes 26 and 27 of the lattice but the cable is not rectilinear and is deviated by some nodes of the lattice, such as nodes 28 and 29. Node 28 is provided with a groove 30 and node 29 is provided with an internal channel 31 for deviating cable 21. Only a part of the arms of the nodes is shown on the drawing.
The invention is not limited to a specific geometric pattern of the bars but preferably the bars of the lateral faces of the lattice are disposed along the sides of equilateral or isosceles triangles and/or along the sides of rectangles or squares. The lateral faces are planes inclined with respect to the vertical, as in the shown embodiment; in other embodiments, the lateral faces are vertical.
The sides and the bottom of the lattice are made watertight by any means but, preferably, the watertightness is obtained by a plurality of concrete walls which are sealingly fixed to or integral with the bars of the lattice which are present in the side faces and in the bottom face of the lattice and preferably the concrete walls which make watertight a side of the lattice are disposed according to a corrugated pattern, which reduces the effect of difference of temperature between the part of the side which is in water and the part of the side which is above water. Such difference of temperature, which in iced seas may be 50° C. or more, might provoke dilatation stresses detrimental to the side walls if the walls were plane. | A ballastable concrete base for an offshore platform is essentially constituted by a volume formed by a three-dimensional lattice of concrete bars interconnected at concrete nodes. Some of the nodes are interconnected by prestress cables passing outside the bars and optionally past intermediate nodes. The cables three-dimensionally prestress the lattice as a whole, and the base further includes means for making watertight the side and the bottom of the lattice. | 4 |
FIELD OF THE INVENTION
This invention relates to a transparent, substantially rigid gel, substantially hydrocarbon-free, substantially stearic acid-free, and syneresis-free, pillar or supported candle article comprising a vegetable-based solvent admixed with an ester-terminated, or tertiary amide-terminated polyamide resin. A system-compatible functional composition which is one or more of a perfume composition, an insect repellent composition and/or an air freshener composition is preferably added to the candle.
BACKGROUND OF THE INVENTION
Transparent pillar or supported candles which release fragrances on use and which are fabricated from materials other than paraffin wax are known in the prior art and are commercially desirable. Such candles fabricated using non-aqueous ester-terminated polyamide resins are disclosed in U.S. Pat. Nos. 6,111,055, 6,242,509 and 6,214,063; U.S. patent application Ser. No. 2001/0029696 published on Oct. 18, 2001, the U.S. Patents and patent application hereby incorporated by reference; and PCT Application WO 00/73408 A1. However, all of the aforementioned disclosures require the use of the hydrocarbon, “mineral oil” as a solvent therefor or as included as a substantial part of the solvent which is necessary for the operation of the candle.
In addition, candles which release fragrance on use and which contain vegetable-based materials such as soy derivatives for all or a substantial portion of their structures are also commercially desirable and are known in the prior art, for example, the candles disclosed in the ECOWAX™ website, by NGI, Inc., P.O. Box 528097, Chicago, Ill. 60652-8097, and in U.S. Pat. Nos. 6,063,144, 6,086,644, and U.S. Published Patent Application 2001/0013195 published on Aug. 16, 2001, these patents and application hereby incorporated by reference. However, the aforementioned prior art does not disclose or suggest, transparent substantially rigid gel candles having structures that include vegetable-based solvents that are substantially hydrocarbon-free and substantially stearic acid free.
It is well known to those having ordinary skill in the art that inclusion of hydrocarbons such as mineral oil and paraffin wax, as well as stearic acid, either as a structural component and/or as a solvent component gives rise to emission of non-desirable substances into the environment surrounding the candle on use thereof.
Accordingly, a need exists for a transparent, substantially hydrocarbon-free, substantially stearic acid-free and syneresis-free candle article which, on use, releases to the environment surrounding the candle, one or more system-compatible functional compositions and which has, for its structure, a vegetable-based solvent admixed with an environmentally-acceptable and useful resin such as an ester-terminated polyamide or a tertiary amide-terminated polyamide.
SUMMARY OF THE INVENTION
Our invention provides a transparent, substantially rigid gel, substantially hydrocarbon-free, substantially stearic acid-free, and syneresis-free pillar or supported candle article having, for its structure, a vegetable-based solvent admixed with an ester-terminated and/or a tertiary amide-terminated polyamide resin, and further admixed with the resin and solvent, a system-compatible functional composition which is one or more of a perfume composition, an insect repellent composition and/or an air freshener composition. In addition, our invention provides a process for making such a candle article.
More particularly, our invention provides a transparent, substantially hydrocarbon-free, substantially stearic acid-free, syneresis-free candle article having consistently-maintained functional composition integrity on use thereof comprising at least one substantially upright wick partially imbedded in a stiff, monophasic, thermally reversible composition consisting essentially of:
(a) from about 75% by weight of said candle up to about 99% by weight of said candle of a gellant-solvent-surfactant/additional solvent system consisting essentially of:
(i) from about 20% to about 70% by weight of said candle of a gellant which is, in the alternative or in combination (A) at least one ester-terminated polyamide; and/or (B) at least one tertiary amide-terminated polyamide; (ii) from about 15% to about 60% by weight of said candle of a vegetable-based solvent which is, in the alternative or in combination: (A) at least one methyl ester of a vegetable-derived C 12 –C 18 carboxylic acid and/or (B) at least one glyceryl ester of a vegetable-derived C 10 carboxylic acid and, optionally admixed therewith, an additional solvent which is, in the alternative or in combination dipropylene glycol and/or isopropyl myristate; and (iii) optionally, from about 3% up to about 20% by weight of said candle of at least one surfactant having a hydrophile/lipophile balance in the range of from about 3 up to about 7, which is, in the alternative or in combination, di(hydroxyethoxy)coconut amine, (hydroxy-triethoxy)coconut amine, (hydroxydiethoxy)coconut amine, N-(hydroxyethoxy)-N-(hydroxydiethoxy)coconut amine, diethylene glycol mono(nonylphenyl)ether, hydroxytriethoxydodecane and/or hydroxytriethoxytridecane;
(b) from about 1% to about 25% by weight of said candle of a system-compatible functional composition which is, in the alternative or in combination, (A) a perfume composition;(B) an insect repellent composition and/or (C) an air freshener composition; and (c) optionally, one or more additives which is, in the alternative or in combination an antioxidant, a stabilizer, a colorant and/or a flame retardant which additives do not compromise the transparency of the candle.
The term, “substantially stearic acid-free” is intended herein to mean that the concentration of stearic acid is less than 1% of the weight of the candle article of our invention; more preferably, less than 0.5% of the weight of the candle article of our invention and most preferably less than 0.1% of the weight of the candle article of our invention.
The term “substantially hydrocarbon-free” is intended herein to mean that the concentration of any hydrocarbon in the candle article of our invention, e.g. paraffin wax or mineral oil, is less than 1% of the weight of the candle article of our invention; more preferably, less than 0.5% of the weight of the candle article of our invention; and most preferably less than 0.1% of the weight of the candle article of our invention.
The term “system-compatible functional composition” is herein intended to mean functional compositions, for example fragrance compositions which, when made part of the gellant-solvent system do not compromise the transparency of the candle by causing haze or cloudiness, due to, for example, phase separation, or syneresis to occur as a result of the composition being admixed with the gellant-solvent system.
The term, “consistently-maintained functional composition integrity” is intended herein to mean that when the candle is in use, the proportions of the constituents and the chemical properties of the constituents of the functional composition, e.g. the fragrance composition that is evolved into the environment on use of the candle article of our invention are substantially identical to the proportions and chemical properties of the constituents originally present in the candle article and originally admixed with the gellant-solvent system.
The term “stiff” is herein intended to mean that the container candle or pillar candle of our invention is self-supporting and non-flowable at ambient temperatures or less and at ambient pressures, e.g. at temperatures of <35° C. and at pressures of about 1 atmosphere absolute.
The term “monophasic” is herein intended to mean that the candle of our invention on use or when not in use exists in one unitary phase without any phase separation resulting from the inclusion in the gellant-solvent system of a functional composition, e.g. a fragrance composition.
The term “thermally reversible” is herein intended to mean that the candle of our invention retains the original proportions of the constituents of its composition and retains its original physical characteristics and its original dimensions on use thereof, and subsequent to use thereof.
Two alternative preferable embodiments exist for the aforementioned article:
(a) A surfactant-containing candle wherein the gellant-solvent-surfactant/additional solvent system consists essentially of:
(i) from about 20% to about 70% by weight of said candle of a gellant which is, in the alternative or in combination (A) at least one ester-terminated polyamide and/or (B) at least one tertiary amide-terminated polyamide; (ii) from about 15% to about 60% by weight of said candle of a vegetable-based solvent which is, in the alternative or in combination (A) at least one methyl ester of a vegetable-derived C 12 –C 18 carboxylic acid and/or (B) at least one glyceryl ester of a vegetable-derived C 10 carboxylic acid; and (iii) from about 3% to about 20% by weight of said candle of at least one surfactant having a hydrophile/lipophile balance in the range of from about 3 to about 7, which is, in the alternative, or in combination (hydroxytriethoxy)coconut amine, di(hydroxyethoxy)coconut amine, (hydroxydiethoxy)coconut amine, N(hydroxyethoxy)-N-(hydroxydiethoxy)coconut amine, diethylene glycol mono(nonylphenyl)ether, hydroxytriethoxydodecane and/or hydroxytriethoxytridecane.
(b) A surfactant-free isopropyl myristate-containing candle of wherein the gellant-solvent/additional solvent system consists essentially of:
(i) from about 20% to about 70% by weight of said candle of a gellant which is, in the alternative or in combination (A) at least one ester-terminated polyamide and/or (B) at least one tertiary amide-terminated polyamide; and (ii) from about 15% to about 60% by weight of said candle of a vegetable-based solvent which is, in the alternative or in combination, (A) at least one methyl ester of a vegetable-derived C 12 –C 18 carboxylic acid and/or (B) at least one glyceryl ester of a vegetable-derived C 10 carboxylic acid and, admixed therewith, an additional solvent, isopropyl myristate.
In the case where a surfactant is included in the gel matrix body of the candle article of our invention, the candle article of our invention is preferably prepared according to a process herein below, and in the Examples, herein, referred to as “Process α”, comprising the steps of:
(a) mixing the gellant, solvent and surfactant at a temperature in the range of from about 95° C. to about 110° C. for a sufficient time to cause the admixture to be a stable single liquid phase; (b) cooling the resulting gellant-solvent-surfactant system mixture to a temperature in the range of from about 75° C. to about 85° C.; (c) admixing a system-compatible functional composition with the resulting gellant-solvent-surfactant system mixture thereby forming a functional composition-gellant-solvent-surfactant system mixture; (d) optionally adding one or more additives such as an antioxidant, a stabilizer, a colorant and/or a flame retardant to the resulting functional composition-gellant-solvent-surfactant system mixture; (e) placing the resulting mixture into a mold while the resulting mixture is in the liquid phase; (f) causing at least 1 candle wick to be embedded in the resulting liquid phase mixture; and (g) cooling the resulting mixture to ambient temperature whereby a candle is formed which may, but need not, have two oppositely-situated substantially parallel horizontally-disposed planar surfaces, each of which is substantially perpendicular and juxtaposed to a substantially vertically-disposed surface.
In the case where the gel matrix includes isopropyl myristate, but may not include a surfactant, the process, herein below and in the Examples, infra, referred to as “Process β” for preparing the candle article of our invention comprises the steps of;
(a) mixing the gellant, solvent and isopropyl myristate at a temperature of about 100° C. for a time period sufficient to cause the admixture to be a stable single liquid phase; (b) cooling the resulting gellant-solvent-isopropyl myristate system mixture to a temperature of about 90° C.; (c) admixing a system-compatible functional composition with the gellant-solvent-isopropyl myristate mixture thereby forming a functional composition-gellant-solvent-isopropyl myristate system mixture; (d) optionally adding one or more additives such as an antioxidant, a stabilizer, a colorant and/or a flame retardant to the resulting mixture; (e) placing the resulting mixture in a molding while the resulting mixture is in the liquid phase; (f) causing at least 1 candle wick to be embedded in the resulting liquid phase mixture; and (g) cooling the resulting mixture to ambient temperature whereby a candle is formed which may, but need not, have two oppositely situated substantially parallel horizontally-disposed planar surfaces, each of which is substantially perpendicular and juxtaposed to a substantially vertically-disposed surface.
In each of the above-mentioned cases, the resulting candle may, if desired, be coated by means of inclusion in the process of our invention, herein below and in the Example, infra, referred to as “Process γ”, the following additional steps (h), (i) and (j):
(h) admixing a fatty acid-dimer based polyamide resin with a lower alkanol solvent at a temperature of about 60° C. for a time period sufficient to cause the polyamide resin to be dissolved in said lower alkanol solvent thereby forming a polyamide-lower alkanol solution, wherein the weight ratio of polyamide resin:lower alkanol solvent is from about 2:3 to about 3:2; (i) coating the resulting solution onto said vertically-disposed surface while maintaining the temperature of the solution at about 60° C.; and (j) cooling the resulting coated candle to ambient temperature.
DETAILED DESCRIPTION OF THE INVENTION
As stated herein, the gellant used in the candle article of our invention is, in the alternative or in combination (A) at least one ester-terminated polyamide or (B) at least one tertiary amide-terminated polyamide.
Preferable ester-terminated polyamides useful in the practice of our invention are those disclosed in U.S. Pat. No. 5,998,570 the disclosure of which is incorporated herein by reference, and include those ester-terminated polyamides prepared by reacting “x” equivalents of a dicarboxylic acid wherein at least 50% of those equivalents are from polymerized fatty acid, “y” equivalents of ethylenediamine and “z” equivalents of an alcohol which is in the alternative, or in combination, cetyl alcohol and/or stearyl alcohol wherein:
0.9≦{x/(y+z)}≦1.1 and 0.1≦{z/(y+z)}≦0.7.
More preferably, the ester-terminated polyamide is one of a group having a weight-average molecular weight of about 6000 and a softening point in the range of from 88° C. up to 94° C. prepared by reacting “x” equivalents of C 36 dicarboxylic acid, “y” equivalents of ethylenediamine and “z” equivalents of an alcohol which is, in the alternative or in combination cetyl alcohol and/or stearyl alcohol wherein 0.9≦{x/(y+z)}≦1.1 and 0.1≦{z/(y+z)}≦0.7 as disclosed in Published U.S. Patent Application 2001/0031280 published on Oct. 18, 2001, the specification incorporated herein by reference. Most preferable are the mineral oil-free ester-terminated polyamides, UNICLEAR™ 100 and UNICLEAR™ 100V, Arizona Chemical Company, Panama City, Fla.
Preferable tertiary amide-terminated polyamides useful in the practice of our invention are those disclosed in U.S. Pat. No. 6,268,466, the specification is incorporated herein by reference, and include those tertiary amide-terminated polyamides prepared by reacting “x” equivalents of dicarboxylic acid wherein at least 50% of those equivalents are from polymerized fatty acid, “y” equivalents of ethylenediamine and “z” equivalents of a monofunctional reactant having a secondary amine group as the only reactive functionality wherein 0.9≦{x/(y+z)}≦1.1 and 0.1≦{z/(y+z)}≦0.7. Most preferable are those tertiary amide-terminated polyamides disclosed in Example 1 of U.S. Pat. No. 6,268,466.
The solvents which are useful in the practice of our invention are methyl esters of C 12 –C 8 carboxylic acids or glyceryl esters of vegetable-derived C 10 carboxylic acids. The preferred vegetable-based solvents useful in the practice of our invention are (A) the methyl ester of soy fatty acid, referred to herein as “soybean methyl ester”, the soy fatty acid being a mixture containing about 26% oleic acid, about 49% of linoleic acid about 11% of linolenic acid and about 14% of saturated fatty acids, and (B) the tri-glyceride of a mixture of caprylic acid and capric acid, for example the composition marketed under the trademark NEOBEE®-M5, Stepan Chemical Company, Northfield, Ill.
A preferred solvent useful in the practice of our invention is a mixture of soy fatty acid methyl ester and isopropyl myristate with the weight ratio of soy fatty acid methyl ester:isopropyl myristate being from about 2:1 to about 20:1.
When a surfactant is used in the gellant-containing system of the candle article of our invention, such surfactant has a hydrophile/lipophile balance, referred to herein as “HLB”, in the range of from about 3 to about 7, and may be in the alternative, or in combination, di(hydroxyethoxy)coconut amine, for example, PEG-2 Cocamine marketed as PROTOX™ C-2, Protameen Chemicals, Inc., Totowa, N.J.; (hydroxy-triethoxy)coconut amine, PEG-3 Cocamine, (hydroxy-diethoxy)coconut amine, N-(hydroxyethoxy)-N-(hydroxydiethoxy)coconut amine, diethylene glycol mono(nonylphenyl)ether, such as, nonoxynol-2 having an HLB=4.6, marketed as IGEPAL® CO-210, Rhone-Poulenc Surfactants and Specialties, L.P., Cranbury, N.J.; hydroxytriethoxydodecane, such as, TOMADOL™ 23-1, Tomah Products, Inc., Milton, Wis. and hydroxytriethoxytridecane.
As stated herein, the candle of our invention includes a system-compatible functional composition, for example, a fragrance composition, an air freshener composition or an insect repellent composition. Each component of such composition preferably has a Clog 10 P of between 2.5 and 8.0, according to the inequality: 2.5≦Clog 10 P≦8.0, wherein the term “Clog 10 P” represents the calculated logarithm to the base 10 of the n-octanol/water partition coefficient of the said component.
The log 10 P of many perfume ingredients has been reported; for example, the Pomona92 database, available from Daylight Chemical Information Systems, Inc. (Daylight CIS), Irvine, Calif., contains many, along with citations to the original literature. However, the log 10 P value are most conveniently calculated by the “CLOGP” program, also available from Daylight CIS. This program also lists experimental log 10 P values when they are available in the Pomona92 database. The “calculated log 10 p” (Clog 10 P) is determined by the fragment approach of Hansch and Leo (cf., A. Leo in Comprehensive Medicinal Chemistry, Vol.4, C. Hansch, P. G. Sammens, J. B. Taylor and C. A. Ramsden, Eds., p.295, Pergamon Press, 1990. The fragment approach is based on the chemical structure of each perfume ingredient, and takes into account the numbers and types of atoms, the atom connectivity and the chemical bonding. The Clog 10 P value which are the most reliable and widely used estimates for this property, are preferably used instead of the experimental log 10 P values for the selection of perfume ingredients which are useful in the gel matrix air freshener articles of our invention.
Specific examples of preferred fragrance, air freshener and insect repellant composition components useful in the gellant system of the candle article of our invention is as follows:
Fragrance Component
Clog 10 P value
α-Terpineol
2.569
Dihydromyrcenol
3.03
δ-Undecalactone
3.830
Benzophenone
3.120
α-Irone
3.820
Nerol
2.649
6-Phenyl heptanol-2
3.478
1-Phenyl hexanol-5
3.299
α-Santalol
3.800
Iso-eugenol
2.547
Linalyl acetate
3.500
Amyl salicylate
4.601
β-Caryophyllene
6.333
Cedrol
4.530
Cedryl acetate
5.436
Cedryl formate
5.070
Ethyl undecylenate
4.888
Geranyl anthranilate
4.216
Linalyl benzoate
5.233
Patchouli alcohol
4.530
5-Acetyl-1,1,2,3,3,6-
5.977
hexamethyl indane
d-Limonene
4.232
Cis-p-t-butylcyclohexyl
4.019
acetate
The candle article of our invention can, if desired be coated, for example with a fatty acid dimer-based polyamide resin such as UNI-REZ® 2228, Arizona Chemical Company, Jacksonville, Fla. As a further example, the candle article of our invention may be substantially in the shape of an upright cylinder or conical frustum having substantially planar horizontally-disposed upper and lower surfaces, each of which surface is substantially perpendicular to a common substantially vertically-disposed surface juxtaposed to each of said horizontally-disposed surfaces, and the “substantially vertically-disposed surface” is the surface that is preferably coated with the aforementioned fatty acid dimer-based polyamide resin according to the process of our invention as set forth herein and as exemplified infra.
The following non-limiting examples are presented for purposes of illustration:
EXAMPLE A
Preparation of Air Freshener Fragrance for Gellant System of Candle Article
The following fragrance was prepared for use in Part “A” of Examples 1–4, infra:
Ingredients
Parts by Weight
α-Irone
7.0
Dihydromyrcenol
4.0
Benzophenone
3.0
β-Caryophyllene
2.0
Linalyl acetate
12.0
Nerol
7.0
Cedrol
8.0
Patchouli alcohol
2.0
EXAMPLE B
Preparation of Fragrance for Gellant System of Candle Article
The following fragrance was prepared for use in Examples 5 and 6, herein:
Parts by
Ingredients
Weight
Amyl salicylate
4.0
β-Caryophyllene
14.0
Cedryl acetate
16.0
Cyclohexyl salicylate
4.0
γ-Dodecalactone
3.0
Geranyl anthranilate
3.0
α-Irone
10.0
EXAMPLES 1 and 2
Container candles are prepared according to “Process β “described herein:
Example 1
Example 2
Ingredients
(Parts by Weight)
(Parts by Weight)
UNICLEAR ® 100 V
24
24
Soy Methyl Ester
58
60
Dipropylene Glycol
3
0
PEG-2 Cocamine
0
0.5
TOMADOL ® 23-1
5
5
Fragrance of Example A,
5
5
supra
Isopropyl myristate
5
5
Hexylene glycol
0
0.5
EXAMPLES 3 and 4
Pillar candles are prepared according to “Process α”, described herein:
Example 3
Example 4
Ingredient
(Parts by Weight)
(Parts by Weight)
UNICLEAR ™ 100 V
50
50
Soy Methyl Ester
40
0
NEOBEE ® M-5
0
30
IGEPAL ® CO-210
12.5
12.5
PEG-2 cocamine
2.5
2.5
Fragrance of Example A,
5
5
supra
Pillar candles are prepared according to “Process β” described herein as modified by “Process γ” as described herein:
Example 5
Example 6
Ingredients
(Parts by Weight)
(Parts by Weight)
UNICLEAR ™ 100 V
50
50
Soy Methyl Ester
40
37
Isopropyl Myristate
5
8
Fragrance of Example B,
5
5
supra
The candles of Examples 5 and 6 were coated with UNI-REZ® 2228 in accordance with the procedure of “Process γ” described herein.
Each of the candles of Examples 1–6, inclusive, showed no syneresis after 30 days. Each of the candles of Examples 1–6 was clear after 30 days. After 30 days, each of the candles was placed in a two ounce glass container and the containers were then stored in a freezer operating at 10° C. for a period of 10 days. None of the candles showed cracks at the end of the 10-day period.
Insect repellent candles were prepared using the same formulations as in Examples 1–6 with the exception that the fragrance formulations of Examples A and B were replaced by insect repellent formulations, containing nerol, citronellol, geraniol, 3,7-dimethyl octanol-1, and β-elemene as described in U.S. Pat. No. 6,255,356, the disclosure of which is incorporated herein by reference. Each of the “insect repellent” candles showed identical effects on storage as the candles of Examples 1–6.
Each of the candles of the aforementioned Examples 1–6, inclusive, can, optionally, contain an “additive” as set forth herein which does not compromise the transparency property of the candle: an antioxidant, a stabilizer, a colorant and/or a flame retardant. An example of a preferred colorant is a thermochromic colorant as disclosed in Hannington et al., Published U.S. Patent Application 2001/0031438 published on Oct. 18, 2001, the specification is incorporated herein by reference. Additional examples of preferred colorants useful in the practice of our invention are disazo dyestuffs as disclosed in U.S. Pat. No. 6,319,290, the specification for which is incorporated herein by reference. The range of use of such colorants is from about 0.01% up to about 0.5% by weight of the candle.
Each of the candles of the aforementioned Examples 1–6, inclusive can contain one or more icons, clear or “main fill” or “overpour” as disclosed in U.S. Pat. No. 6,214,063, cited herein, with the exception than in place of the UNICLEAR™ 80 ETPA shown to be used, for example in Tables 1, 2 and 3 thereof, UNICLEAR™ 100V is used. Other U.S. Patents disclosing icons include U.S. Pat. Nos. 5,679,334; 6,071,506; 6,294,162, 6,309,715, the specification of these patents as well as U.S. Pat. No. 6,214,063 are incorporated herein by reference.
From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. | Described is a transparent syneresis-free candle which is substantially hydrocarbon-free, e.g., mineral oil-free and paraffin wax-free; substantially stearic acid-free and consistently-maintained functional compositional integrity on use thereof. The candle composition contains a gellant that is an ester-terminated polyamide or a tertiary amide-terminated polyamide, a non-hydrocarbon solvent which is a vegetable-derived fatty acid ester, and a system-compatible functional fragrance composition, an insect repellent composition and/or an air freshener composition. The candle can be a pillar candle which is free-standing or a container candle. | 2 |
BACKGROUND OF THE INVENTION
Signal generation instruments perform many functions necessary to the testing, operation and maintenance of modern electronic applications. These signal generation instruments include pulse generators, pattern generators, data generators, pseudo-random bit sequence (“PRBS”) generators, controllable jitter injection, and timing generators. The digital waveforms and data signals generated by these instruments, such as generating digital pulses, high-speed clock signals, square waves, and flexible serial or parallel bit patterns and data streams, may be utilized in many applications requiring pulse and data generation. Applications include frequency upconversion, time-domain reflectometry, emissions testing, and phase coherency, among many other applications.
A typical pulse train generated by these signal generation instruments has some important features: (a) a frequency-domain spectrum with comb spacing equal to the inverse of the pulse-repetition frequency (“PRF”) rate; (b) a frequency-domain amplitude shape defined by the sinc function (with a max-to-null bandwidth equal to the inverse of the pulse width); and (c) a constant phase difference between adjacent combs.
However, other useful reference signals are also possible. For example, the pulse train may be modulated to spread the energy such that the peak amplitude is lower in the time domain while maintaining the same comb amplitude in the frequency domain. The pulse train may also be filtered so that only a portion of the frequency spectrum is utilized.
FIGS. 1A and 1B show the time and frequency-domain descriptions 100 , 120 , respectively, of an ideal pulse train. In FIG. 1A , the time-domain description 100 of an ideal pulse train 102 is shown. The separation of the rising edges, Δt 104 , generally known as the pulse period, is equal to the reciprocal of the PRF, f rep 122 , where Δt=1/f rep .
In FIG. 1B , the corresponding frequency-domain description 120 of the ideal pulse train is shown. That is, the periodic pulse train is Fourier-transformed. The amplitude spectrum of the pulse train consists of many equidistant spectral points 122 , which are denoted by the circles in FIG. 1B , where the amplitude values are represented by the amplitude axis 130 . The unwrapped phase spectrum of the pulse train consists of many equidistant spectral points 123 , which are denoted by the triangles in FIG. 1B , where the phase values are represented by the phase axis 132 . The spacing 124 of the spectral points 122 and 123 is equal to the repetition rate f rep of the periodic pulse train. The width of the amplitude spectrum 128 until the first null, f o 126 , is determined by the pulse width, t p 106 , where f o =1/t p . The spectral width 128 , therefore, increases with decreasing pulse width. The unwrapped phase spectrum 123 is constant up to the frequency of the first null 126 in the amplitude spectrum 122 .
Known methods of pulse generation include the use of step-recovery diodes (“SRDs”) and non-linear transmission lines (“NLTLs”). SRDs are used for pulse generation because when switched from forward bias to reverse bias, SRDs have fast recovery time, and as a result, are capable of producing pulses with sharp and fast rise times. NLTLs are also used for pulse shaping, i.e., pulse narrowing and edge sharpening. Unfortunately, both of these methods typically have poor phase responses, have varying output level with input drive level, have high PRFs or a narrow range of PRFs, and are not easily manufactured utilizing standard surface-mount technology (which results in higher manufacturing costs).
Another type of pulse generator that uses logic gates and logic delay elements is disclosed in U.S. Pat. No. 4,583,008 titled “Retriggerable Edge Detector for Edge-Actuated Internally Clocked Parts” to Grugett. This type of pulse generator is typically used to create clock signals in digital circuits. Unfortunately, as pulse widths of logic circuits decrease to tens of picoseconds, digital circuit processes require reduced voltage swings. The reduced voltage swing also reduces the available signal-to-noise ratio of the ouput pulse. Another disadvantage of the logic pulse generator is that the input signal must be a square wave or pulse train. These signals, however, are difficult to generate using microwave frequency signal generators.
Therefore, there is a need for an improved pulse generator that has lower manufacturing costs, better phase response and output characteristics, higher signal-to-noise ratio, and that allows for PRF rates that are lower or higher than conventional pulse generators. This improved pulse generator should also be usable with input signals from conventional microwave frequency signal generators.
SUMMARY
A split signal pulse generator (“SSPG”) that includes a signal splitter, signal lines of unequal time delay, and a difference amplifier is disclosed. The SSPG may also include a DC offset in signal communication with an input of the difference amplifier that suppresses a portion of the out-going signals from the difference amplifier. The difference amplifier may be a limiting difference amplifier that limits the amplitude of the out-going signals. Additionally, the SSPG may include an input amplifier or a divider in signal communication with the SSPG. These two optional additions may improve phase noise or jitter with certain input signals and also shape certain input signals to allow a larger range of input signals to be used, such as those created by conventional microwave sources.
In an example of operation of the SSPG, an input signal is input to the signal splitter, which generates two output split signals. One of the split signals is time-delayed, creating an amplitude difference between the split signals at the input of the difference amplifier. The amplitude difference is amplified by the difference amplifier, which outputs one or more output signals which may be limited in amplitude. One of the outputs may be a pulse train. Additionally, the SSPG may include a DC offset that is applied between the inputs to the difference amplifier. The application of the DC offset will suppress the opposite-outgoing pulse in the output pulse train, resulting in unidirectional outgoing pulses.
Other systems, methods and features of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
FIG. 1A shows a graphical representation of an example plot of a time-domain description of an ideal pulse train.
FIG. 1B shows a graphical representation of an example plot of a frequency-domain description of an ideal pulse train.
FIG. 2 shows a block diagram of an example of an implementation of a split signal pulse generator (“SSPG”).
FIG. 3 shows a schematic diagram of an example of an implementation of the SSPG shown in FIG. 2 .
FIG. 4A shows a graphical representation of an example of a plot of voltage versus time of the signals going into the difference amplifier shown in FIG. 3 .
FIG. 4B shows a graphical representation of an example of a plot of voltage versus time of the output signals from the difference amplifier shown in FIG. 3 .
FIG. 5A shows a graphical representation of an example of a plot of voltage versus time of the signals going into the difference amplifier shown in FIG. 3 with DC offset applied.
FIG. 5B shows a graphical representation of an example of a plot of voltage versus time of the output signals from the difference amplifier shown in FIG. 3 with DC offset applied.
FIG. 6 shows a block diagram of an example of another implementation of the SSPG that includes an input amplifier.
FIG. 7 shows a block diagram of an example of yet another implementation of the SSPG shown in FIG. 6 that includes a divider.
FIG. 8 shows a graphical representation of an example of a plot of a measurement of a negative pulse output of a SSPG.
FIG. 9 shows a graphical representation of an example of a plot of the amplitude and phase spectrum of the pulse shown in FIG. 8 .
FIG. 10 shows a flow diagram of the steps performed in an example of a process of operation of the SSPG shown in FIGS. 2 and 3 .
DETAILED DESCRIPTION
In the following description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and which show, by way of illustration, a specific embodiment in which the invention may be practiced. Other embodiments may be utilized and structural changes may be made without departing from the scope of this invention.
In general, the invention is a split signal pulse generator (“SSPG”) that allows pulse-repetition frequency (“PRF”) rates that are below (or above) conventional pulse generators. In an example of operation, the SSPG may operate at PRF rates that may be varied from as low as one millihertz to as high as multiple gigahertz clock rates.
In FIG. 2 , a block diagram of an example of an implementation of the SSPG 200 is shown. The SSPG 200 may include a splitter module 202 , delay module 204 , and difference amplifier 206 . In this implementation example, the splitter module 202 is in signal communication with both the difference amplifier 206 and delay module 204 via signal paths 210 and 212 , respectively. The difference amplifier 206 is also in signal communication with the delay module 204 via signal path 214 .
In an example of operation, the SSPG 200 receives an input signal 208 at the splitter module 202 and in response, the splitter module 202 splits the input signal 208 to produce two split signals (first split signal 216 and second split signal 218 ) that are passed to difference amplifier 206 and delay module 204 via signal paths 210 and 212 , respectively. In response to receiving the second split signal 218 , the delay module 204 delays the second split signal 218 to produce a delayed split signal 220 that is passed to the difference amplifier 206 via signal path 214 . The difference amplifier 206 receives the first split signal 216 and the delayed split signal 220 and in response produces an output 222 that is a function of the voltage difference between the first split signal 216 and the delayed split signal 220 . The output 222 may be proportional to the input and may be limited in amplitude.
In FIG. 3 , a schematic diagram of an example of an implementation of the SSPG 300 is shown. Similar to FIG. 2 , the SSPG 300 may include a splitter module 302 , delay module 304 , and difference amplifier 306 . The splitter module 302 may include a splitter circuit that includes, for example, resistors 308 , 310 , and 312 . The splitter module 302 may be in signal communication with the difference amplifier 306 via two transmission lines 314 and 316 . It is appreciated by those skilled in the art that the splitter module 302 and the delay module 304 may be passive or active and may include various types of circuitry.
In an example of operation, the SSPG 300 receives the input signal 318 at the splitter module 302 and in response the splitter module 302 splits the input signal 318 to produce two split signals (first split signal 320 and second split signal 322 ) that are passed to difference amplifier 306 via transmission lines 314 and 316 , respectively. It is appreciated that each transmission line 314 and 316 introduces a time delay in each split signal that is proportional to the length of the respective transmission line. As an example, the first transmission line 314 produces a first time delay on first split signal 320 to produce a first delayed split signal 324 and the second transmission line 316 produces a second time delay on the second split signal 322 , to produce a second delayed split signal 326 (i.e., such as the delayed split signal 220 in FIG. 2 ). The first time delay is proportional to the length of the first transmission line 314 and the second time delay is proportional to the length of the second transmission line 316 .
If the first transmission line 314 and the second transmission line 316 are of different lengths, the length difference creates a time delay between the first delayed split signal 324 and second delayed split signal 326 that is proportional to the difference in length between the first transmission line 314 and second transmission line 316 . It is appreciated by those skilled in the art that the difference in length may be mechanically or electrically tuned by physically stretching a transmission line or by modifying the effective capacitance and inductance of a transmission line. Examples of other means of adjusting lengths of transmission lines include variable or switched delay lines, variable capacitors, and tuning stubs.
The difference amplifier 306 receives the resulting first delayed signal 324 and second delayed signal 326 and in response, produces two differential outputs 328 and 330 that are proportional to the voltage difference between the first delayed split signal 324 and second delayed split signal 326 and that may also be limited in amplitude. The first difference output 328 may be a positive difference output and the second difference output 330 may be a negative difference output. It is appreciated, in this example, that the second difference output 330 is optional and may be utilized as an opposite-going pulse train.
As an example, when input signal 318 is a square wave signal, the difference amplifier 306 produces a positive pulsed output signal at the first difference output 328 and may produce a negative pulsed output signal at the second difference output 330 upon receiving the split signals 324 and 326 . FIG. 4A shows a graphical representation of an example of a plot 400 of voltage 402 (in millivolts) versus time 404 (in picoseconds) of the input split signals 324 and 326 . As an example, the first delayed split signal 324 may be shown in plot 400 as first signal plot 406 and the second delayed split signal 326 may be shown as second signal plot 408 .
Also shown in FIG. 4A is the time delay 440 (in picoseconds) between the first delayed split signal 324 and second delayed split signal 326 . During the duration of time delay 440 , there exists a difference in amplitude voltage 410 (in millivolts) between the first delayed split signal 324 and the second delayed split signal 326 as shown by the first signal plot 406 and the second signal plot 408 , respectively.
FIG. 4B shows a graphical representation of an example of a plot 420 of voltage 422 versus time 424 of the output signals 426 and 428 (corresponding to first differential outputs 328 and 330 ) from the difference amplifier 306 shown in FIG. 3 . The output signals 426 and 428 are the result of amplifying the amplitude difference 410 , which results in the output signals 426 and 428 having pulse widths 442 that correspond to the time delay difference 440 .
In this example, generally, a pulse 430 and an opposite-going pulse 432 will be generated as the first delayed split signal 324 and second delayed split signal 326 transition low and then high, respectively. The opposite-going pulse 432 may be suppressed by applying an optional DC offset 332 (through, for example, optional impedance 334 ) between the inputs of the difference amplifier 306 or by other means appreciated by those skilled in the art, such as, for example, a potentiometer connected to a voltage reference, a digitally-controlled voltage reference, or a current source connected to impedance 334 .
FIG. 5A shows a graphical representation of a plot 500 of voltage 502 (in millivolts) versus time 504 (in picoseconds) of the input split signals 324 and 326 when the DC offset 332 is applied. The DC offset creates a voltage difference between the split signals 324 and 326 . An example of this voltage difference 510 is plotted along with the input signals 506 and 508 .
When this voltage difference 510 and the voltage difference 512 caused by the time delay is amplified by the difference amplifier 306 and the amplifier is limited in amplitude, the opposite-going pulses 432 and 442 , FIG. 4B , will be suppressed, and the resulting pulses will always go in the same direction. FIG. 5B shows a graphical representation of an example of a plot 520 of voltage 522 versus time 524 of the output signals 526 and 528 with opposite-going pulses suppressed. As in the previous example, the width 542 of the pulses corresponds to the time delay difference 540 between the input signals to the difference amplifier 306 . The width 542 also depends on the value of applied DC offset 332 , FIG. 3 , which provides a means of adjusting the width of the pulses when the input signals are not ideal square waves.
In FIG. 6 , a block diagram of an example of another implementation of the SSPG 600 that includes an input amplifier 602 is shown. The input amplifier 602 may be a shaping amplifier that converts an arbitrary input signal 618 to an output signal 620 that more closely approximates a square wave. An example of the class of shaping amplifiers includes a limiting amplifier. Without an input shaping amplifier of sufficient gain, the characteristics of the output pulse train could vary with input drive level for input signals that do not approximate square waves. The addition of the input amplifier 602 allows the use of standard microwave sources, which generally only produce sinusoidal signals.
The SSPG 600 may include the input amplifier 602 and a splitter module 604 , delay module 606 , and difference amplifier 608 . In this implementation example, the input amplifier 602 is in signal communication with the splitter module 604 via signal path 610 . The splitter module 604 is in signal communication with the both the difference amplifier 608 and delay module 606 via signal paths 612 and 614 , respectively. The difference amplifier 608 is also in signal communication with the delay module 606 via signal path 616 .
In an example of operation, the SSPG 600 receives an input signal 618 at the input amplifier 602 , which shapes the input signal 618 and passes the shaped input signal 620 to the splitter module 604 . The splitter module 604 receives the shaped input signal 620 and in response splits the shaped input signal 620 to produce two split signals (first split signal 622 and second split signal 624 ) that are passed to difference amplifier 608 and delay module 606 via signal paths 612 and 614 , respectively. In response to receiving the second split signal 624 , the delay module 606 delays the second split signal 624 to produce a delayed split signal 626 that is passed to the difference amplifier 608 via signal path 616 . The difference amplifier 608 receives the first split signal 622 and the delayed split signal 626 and in response produces an output signal 628 that is proportional to the voltage difference between the first split signal 622 and delayed split signal 626 .
Similar to the example described in FIG. 3 , an opposite-going pulse may also be generated as the first delayed split signal 622 and second delayed split signal 626 transition in the opposite direction. This opposite-going pulse may be suppressed by applying an optional DC offset (not shown) between the inputs of the difference amplifier 608 or by other means.
In FIG. 7 , a block diagram of an example of yet another implementation of the SSPG 700 that includes a divider module 704 is shown. The divider module 704 reduces phase noise and jitter for the SSPG 700 and also shapes the input signal to more closely resemble a square wave. The SSPG 700 may also include a splitter module 706 , delay module 708 , and difference amplifier 710 . In this implementation example, the divider module 704 is in signal communication with splitter module 706 via signal path 714 . The splitter module 706 is in signal communication with the both the difference amplifier 710 and delay module 708 via signal paths 716 and 718 , respectively. The difference amplifier 710 is also in signal communication with the delay module 708 via signal path 720 .
In an example of operation, the SSPG 700 receives an input signal 722 at the divider module 704 , which produces a divided and shaped input signal 726 . The divider module 704 passes the divided input signal 726 to the splitter module 706 . The divider module 704 may be a device capable of lowering the repetition frequency of the input signal 722 by an integer value (i.e., a divide by 2, divide by 4, divide by 8, etc.) in such a manner as to reduce the phase noise and jitter of the amplified input signal 722 and produce a square wave output. Examples of devices that may be utilized as the divider module 704 include sequential logic circuits such as a static frequency divider, ripple counter or other similar type devices. The divider module 704 may include a trigger signal 736 that may be used as a reference to the decreased output repetition frequency of the divided input signal 726 .
The splitter module 706 receives the divided input signal 726 and in response splits the divided input signal 726 to produce two split signals (first split signal 728 and second split signal 730 ) that are passed to the difference amplifier 710 and delay module 708 via signal paths 716 and 718 , respectively. In response to receiving the second split signal 730 , the delay module 708 delays the second split signal 730 to produce a delayed split signal 732 that is passed to the difference amplifier 710 via signal path 720 . The difference amplifier 710 receives the first split signal 728 and the delayed split signal 732 and, in response, produces an output 734 that is proportional to the voltage difference between the first split signal 728 and delayed split signal 732 .
Again, similar to the example described in FIG. 3 , an opposite-going pulse may also be generated as the first delayed split signal 728 and second delayed split signal 732 transition in the opposite direction. This opposite-going pulse may be suppressed by applying an optional DC offset (not shown) between the inputs of the difference amplifier 710 .
The divider module 704 may be replaced by a multiplier module (not shown) that increases the repetition frequency of input signal 724 by an integer value and also produces a square wave output. This may result in more energy per output tone (in the frequency domain) in output signal 734 and may also allow lower frequency input signals 722 to be used.
As an example of operation, in FIG. 8 , a graphical representation of an example of a plot 800 of voltage 802 (in volts) versus time 804 (in nanoseconds) of a measurement of a negative pulse output 806 of the SSPG 200 , FIG. 2 , with a pulse width of about 35 picoseconds and the opposite-going pulse suppressed, is shown.
Additionally, FIG. 9 shows a graphical representation of an example of a plot 900 of the amplitude 902 (in dBV) versus frequency 906 (in gigahertz) of a measurement of the amplitude spectrum 908 for the pulse 806 shown in FIG. 8 with a repetition frequency of 10 MHz, and the phase 904 (in degrees) versus frequency 906 (in gigahertz) of a measurement of the phase spectrum 910 for the pulse 806 shown in FIG. 8 with a repetition frequency of 10 MHz.
FIG. 10 shows a flow diagram 1000 of the steps performed in an example of a process of operation of the SSPG 200 shown in FIG. 2 . The process begins in step 1002 , and in step 1004 , a splitter module of SSPG 200 , FIG. 2 , receives an input signal. In step 1006 , the splitter module splits the signal into two split signals, a first split signal and a second split signal. The second split signal is then time delayed, in step 1008 , to produce a delayed split signal that is input to the difference amplifier with the first split signal. In optional step 1010 , an optional DC offset is applied between the inputs of the difference amplifier, which amplifier amplifies the difference between the first split signal and the delayed split signal and limits the output amplitude, producing an output that is a pulse train with each pulse going in the same direction. The process then ends in step 1012 .
While the foregoing description refers to the use of an SSPG, the subject matter is not limited to such a system. Any signal generation instruments or systems that could benefit from the functionality provided by the components described above may be implemented in the SSPG.
Moreover, it will be understood that the foregoing description of numerous implementations has been presented for purposes of illustration and description. It is not exhaustive and does not limit the claimed inventions to the precise forms disclosed. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention. | A split signal pulse generator (“SSPG”) that generates a difference signal from two split signals from a splitter module, where one of the split signals may be time delayed by a delay module, where the delay module may be a transmission line having a time delay or an adjustable delay line. The SSPG may include an input amplifier configured to shape an input signal received by the splitter module. A method of generating a difference signal is also provided. | 6 |
This application is a continuation of application Ser. No. 07/700,223, now abandoned, filed May 14, 1991, which is a division of application Ser. No. 07/473,540, filed Feb. 1, 1990, now U.S. Pat. No. 5,045,165.
BACKGROUND OF THE INVENTION
This invention relates to carbon films used to protect magnetic media.
Metallic magnetic thin film disks used in memory applications typically comprise a substrate material which is coated with a magnetic alloy film which serves as the recording medium. Typically, the recording medium used in such disks is a cobalt-based alloy such as Co--Ni, Co--Cr, Co--Ni--Cr, Co--Pt or Co--Ni--Pt which is deposited by vacuum sputtering as discussed by J. K. Howard in "Thin Films for Magnetic Recording Technology: A Review", published in Journal of Vacuum Science and Technology in January 1986, incorporated herein by reference. Other prior art recording media comprises a Co--P or Co--Ni--P film deposited by chemical plating as discussed by Tu Chen et al. in "Microstructure and Magnetic Properties of Electroless Co--P Thin Films Grown on an Aluminum Base Disk Substrate", published in the Journal of Applied Physics in March, 1978, and Y. Suganuma et al. in "Production Process and High Density Recording Characteristics of Plated Disks", published in IEEE Transactions on Magnetics in November 1982, also incorporated herein by reference.
Usually it is necessary to protect such magnetic media by sputtering a protective overcoat such as a carbon overcoat. An example of such a sputtered carbon overcoat is described by F. K. King in "Data Point Thin Film Media", published in IEEE Transactions on Magnetics in July 1981, incorporated herein by reference. Unfortunately, bare carbon films typically exhibit an excessively high friction coefficient and poor wear resistance, thus necessitating the application of a lubricant layer to the carbon.
It is also known to provide a carbon film containing hydrogen by using a plasma chemical vapor deposition technique, e.g. as described by Ishikawa et al. in "Dual Carbon, A New Surface Protective Film For Thin Film Hard Disks", IEEE Transactions on Magnetics, September 1986 incorporated herein by reference. During such a process, a hard, durable carbon layer (which Ishikawa refers to as i-carbon) is magnetron-sputtered over a film of a magnetic alloy. Thereafter, a second carbon film (p-carbon), which exhibits a lower friction coefficient than the i-carbon, is deposited by plasma-decomposition of a hydrocarbon gas. (In a variation of this process, Ishikawa discusses plasma decomposing the hydrocarbon gas to form first and second p-carbon layers exhibiting different mechanical properties on the magnetic alloy.)
Unfortunately, Ishikawa's p-carbon layer is difficult to manufacture in a typical continuous in-line sputter deposition production machine. Such a machine is schematically illustrated in FIG. 1, in which a nickel-phosphorus underlayer, a magnetic alloy film and protective carbon overcoat are sputtered onto a substrate 1 in portions 2, 3 and 4 of a single sputtering chamber 5. Substrate 1 is continuously moved by a carrier pallet past nickel-phosphorus alloy sputtering targets 6a, 6b, magnetic alloy sputtering targets 7a, 7b and carbon sputtering targets 8a, 8b. Target shields 19 surround sputtering targets 6 to 8 as shown. Gas sources 9, 10 and 11 introduce argon gas into chamber 5 to facilitate sputtering, while pumps 12, 13 and 14 remove gas from chamber 5. Such in-line sputtering apparatus is widely used in industry today due to its lower cost of operations and simplicity. The Ishikawa plasma decomposition process cannot be performed in in-line sputtering apparatus because Ishikawa's process requires vacuum conditions considerably different than those used in magnetic alloy deposition. Further, gases used in Ishikawa's process (i.e. hydrocarbon gases) can have an adverse effect on the properties of the magnetic layer. This problem is discussed in U.S. Pat. No. 4,778,582, issued to J. K. Howard, which indicates that methane in his sputtering chamber adversely affected the magnetic coercivity of a resulting magnetic alloy. (Col. 2, lines 43-47).
It is also known to deposit carbon films in the presence of small quantities of hydrogen gas. The Howard patent advocates adding a very small quantity of hydrogen to a sputtering chamber in an attempt to render the resulting magnetic disk corrosion resistant. (The mechanism responsible for reduction in corrosion in Howard's process is not well understood.) Unfortunately, Howard does not provide any indication as to how one could improve the wear characteristics of his hydrogen-doped carbon film.
SUMMARY OF THE INVENTION
I have discovered that sputtering carbon onto a magnetic disk in the presence of a large amount of hydrogen causes the resulting carbon film to exhibit superior wear characteristics. Because of this, I can extend the useful life of a magnetic disk. The presence of hydrogen does not adversely affect deposition of other layers elsewhere in the sputtering chamber. Sputtering can be accomplished using DC or RF magnetron sputtering or DC or RF diode sputtering.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates prior art continuous in-line sputtering production apparatus.
FIG. 2 schematically illustrates sputtering apparatus used to form the films of FIGS. 3 to 10.
FIG. 3 illustrates in cross section a magnetic disk constructed in accordance with my invention.
FIG. 4 illustrates the relationship between hydrogen concentration adjacent targets 8a and 8b (FIG. 2) and the gas flow provided by gas source 22 when gas source 11 is off.
FIG. 5A illustrates the wear characteristics of a carbon overcoat sputtered onto a magnetic disk in which no hydrogen was present in the sputtering system.
FIG. 5B illustrates the wear characteristics of a carbon film formed on a magnetic disk in which 20 SCCM of a 20% hydrogen 80% argon gas mixture was introduced into the sputtering chamber during carbon deposition. (Percentages are by volume.)
FIG. 5C illustrates the wear characteristics of a carbon film formed on a magnetic disk in which 40 SCCM of the 20% hydrogen 80% argon gas mixture was introduced into the sputtering chamber during carbon deposition.
FIG. 5D illustrates the wear characteristics of a carbon film formed on a magnetic disk in which 60 SCCM of the 20% hydrogen 80% argon gas mixture was introduced into the sputtering chamber during carbon deposition.
FIG. 6 illustrates the relationship between the increase in friction coefficient between a read/write head and a carbon protective film and time elapsed during a drag test for carbon films sputtered in the presence of varying amounts of hydrogen.
FIG. 7 is a residual gas analysis mass spectrometer measurement of the hydrogen mass peak intensity as a function of calculated hydrogen concentration in a sputtering chamber with the plasma on and with the plasma off.
FIGS. 8A and 8C illustrate Raman spectroscopy curves of carbon films sputtered in the presence and absence of hydrogen, respectively. FIGS. 8B and 8D are deconvoluted spectra of FIGS. 8A and 8C respectively.
FIG. 9 illustrates the D/G peak height and area ratios for Raman spectra of carbon films sputtered in the presence of varying amounts of hydrogen.
FIG. 10 illustrates the positions of the D and G peaks in Raman spectra for varying amounts of hydrogen.
DETAILED DESCRIPTION
FIG. 2 schematically illustrates sputtering apparatus 20 typically used in accordance with my invention. It should be understood, however, that other types of sputtering apparatus could also be used in conjunction with my invention. Sputtering apparatus 20 includes a chamber 5 in which a substrate 1 is placed. Substrate 1 is typically an aluminum disk plated on both sides with a nickel-phosphorus alloy. Substrate 1 is mechanically coupled to a disk pallet carrier which moves substrate 1 past a first, second and third pair of targets 6a, 6b, 7a, 7b and 8a, 8b. Targets 6a, 6b are used to sputter a NiP alloy onto substrate 1 as discussed in U.S. Pat. No. 4,786,564, issued to Chen et al., and incorporated herein by reference. Targets 7a, 7b are thereafter used to sputter a cobalt-nickel-platinum alloy onto substrate 1, while targets 8a, 8b are thereafter used to sputter carbon onto substrate 1. The substrate is then removed from the sputtering chamber. FIG. 3 illustrates in cross section, the resulting disk.
Typical sputtering targets have a width W between 5 and 10 inches. In one embodiment, targets having a width of 8 inches are used. Targets 7a, 7b are separated from targets 8a, 8b and 6a, 6b by a distance D1 of about 1.5 meters. Targets 6a, 7a, 8a are separated from targets 6b, 7b, 8b by a distance D2 of about 6 inches or less. Because of the spacing of the pair of targets, sputtered particles from targets 6 to 8 do not interfere with sputtering from adjacent targets.
Apparatus 20 also includes gas sources 9 to 11 for introducing an inert gas such as argon in the vicinity of targets 6 to 8, respectively. (In other embodiments other inert gases such as krypton or xenon may be used.) Gas evacuation pumps 12 to 14 are provided to remove gas from the vicinity of targets 6 to 8, respectively.
In accordance with one important feature of my invention, a fourth gas source 22 introduces an argon hydrogen gas mixture into chamber 5 in the vicinity of targets 8a, 8b. Thus, during carbon deposition, hydrogen is present in chamber 5 in quantities sufficient to alter the mechanical characteristics of the carbon overcoat. By altering the amount of gas provided by sources 11 and 22, the amount and concentration of hydrogen in the vicinity of targets 8a, 8b are controlled. Of importance, even if hydrogen from gas source 22 diffuses into the vicinity of targets 6a, 6b, 7a or 7b, the hydrogen does not have an adverse effect on the sputtering of the nickel-phosphorus or cobalt-nickel-platinum alloys. In one embodiment, a barrier or wall may be provided to restrict the flow of hydrogen from gas source 22 towards targets 7a, 7b thereby enhancing the hydrogen concentration adjacent targets 8a, 8b.
In one embodiment, an 80:20 argon-hydrogen gas mixture is provided by gas source 22. The reason for this is that hydrogen is explosive, and the presence of tanks of pure hydrogen represent a hazard. In other embodiments, source 22 can provide a gas mixture with other hydrogen concentrations. However, a sufficiently high concentration of hydrogen in the hydrogen/argon gas mixture is required to maintain a high concentration of H 2 at carbon targets 8a and 8b.
FIGS. 5A through 5D illustrate the results of drag tests performed on carbon films formed on a 130 mm diameter magnetic disk. The disks included NiP plated to a thickness of 10 to 15 μm onto an aluminum substrate, and were textured with concentric patterns to a roughness of 40 Å RA. ("RA" is a well known parameter of surface roughness, and is described in the Metals Handbook, edited by H. E. Boyer and T. L. Gall, published by the American Society for Metals in 1985.) During the drag tests, the disks were rotated at 45 rpm while a read/write head dragged across the disk surface approximately 2.11 inches from the center of the disk. The read write heads were thin film heads composed of TiC and Al 2 O 3 , and were pushed against the carbon films in a direction perpendicular to the films with a force of 10 grams. The read-write heads were affixed to a piezo-electric sensor which sensed the strain that the head experienced. (No lubricant was applied to the carbon in these tests.) The X axis in FIGS. 5A through 5D is in units of time. The Y axis is in units of dynamic friction coefficient. The disk in FIG. 5A was manufactured by turning off gas source 11 and 22, so there was no hydrogen in chamber 5. (Any argon present at sputtering targets 8a, 8b originated from gas sources 9 and 10.) As can be seen, without any hydrogen present in the film, the friction coefficient rose to a value of over 1.0 in less than 6 minutes. (The test was terminated shortly after the friction coefficient reached 1.0 to avoid damaging the piezo-electric sensor attached to the read/write head.)
The trace of the friction coefficient has a certain amount of width in FIG. 5A. This is because the friction coefficient varies around the circumference of the disk.
The disk of FIG. 5B was manufactured with gas source 22 providing 20 SCCM of the 80% argon/20% H 2 mixture. (In other words, 4 SCCM of H 2 was introduced into chamber 5.) The friction exhibited by the resulting carbon film rose from a value of 0.2 to 1.0 in less than 8 minutes.
In FIG. 5C, 40 SCCM of the 80% argon/20% H 2 mixture was introduced into sputtering chamber 5 by source 22 while source 11 was off. The friction coefficient exhibited by the resulting carbon film rose to 1.0 in 12 minutes.
In FIG. 5D, 60 SCCM of the 80% argon/20% H 2 mixture was provided by gas source 22 while gas source 11 was off. The friction coefficient from the resulting carbon film rose to a level of about 0.7 and then stopped rising, even after 66 minutes, and the test was terminated.
Although during the above experiments gas source 11 was off, gas source 11 can be used to vary the hydrogen concentration adjacent targets 8a, 8b.
FIG. 4 illustrates the relationship between gas flow from source 22 (20% H 2 /80% argon) and the concentration of hydrogen at targets 8a, 8b. Because of diffusion and gas flow between the different target areas, the hydrogen concentration at targets 8a, 8b does not equal exactly 20%. The curve of FIG. 4 was estimated taking into account the geometry of the sputtering system and flow pattern of gases in the system. (The hydrogen concentration at targets 8a, 8b is substantially equal to the hydrogen concentration at the substrate when the substrate is between targets 8a and 8b.)
Typically, magnetic disks are unacceptable if the friction coefficient is greater than 1.0. Accordingly, the disks of FIGS. 5A, 5B and 5C wore out and became unacceptable relatively quickly. However, as mentioned above, the disk of FIG. 5D remained acceptable, even after 66 minutes. Accordingly, it is seen in FIGS. 5A-5D that the greater the hydrogen concentration in the sputtering chamber, the greater the carbon film performance.
FIG. 6 illustrates the time required during the drag tests for a disk to exceed a friction coefficient of 1.0. The disks produced under gas flows of 0, 20, 40 and 60 SCCM of the 80% argon/20% H 2 mixture in FIG. 6 were generated under the same gas flow conditions as FIGS. 5A, 5B, 5C and 5D, respectively. The Y axis of FIG. 6 is logarithmic. As can be seen, the lifetime of the carbon film is increased by more than an order of magnitude by introducing 60 SCCM of a 20% H 2 /80% argon gas flow hydrogen into the sputtering chamber. The data points for disks manufactured when gas source 22 provided 60 SCCM of the argon/H 2 mixture were estimated, based on slope of the friction vs. time curves from drag tests. The plot in FIG. 6 shows, for a group of samples prepared under different hydrogen concentrations, that a small amount of hydrogen will have almost no effect on the mechanical characteristics of the carbon film, whereas a large amount of hydrogen will have a very dramatic effect on the carbon.
The reason hydrogen affects the friction exhibited by the disks is not completely understood. I have three theories concerning why this result is achieved. According to the article entitled "Evidence for Tribochemical Wear on Amorphous Carbon Thin Films" by Bruno Marchon et al., published at the proceedings of the MRM Conference in Rimini, Italy in 1989 (incorporated herein by reference), carbon wears out primarily through an oxidation phenomenon. When a read/write head strikes a magnetic disk, a great amount of force is exerted on a small portion of the carbon film by the read/write head. This causes localized heating and oxidation of the carbon film. Thus, Marchon reported that carbon wear was prevented or drastically reduced by conducting contact-start-stop tests in a nitrogen (oxygen-free) atmosphere. It is possible that hydrogen doping the carbon film also drastically reduces localized oxidation.
Another possible reason why introduction of hydrogen into a carbon film retards the increase in friction is that as the read/write head and the carbon film wear, the amount of contact area between the read/write head and the disk increases. The presence of hydrogen in the carbon film reduces an attractive force between the read/write head and the carbon, and thus retards the increase in the friction coefficient even when the contact area between the read/write head and carbon increases due to wear.
A third theory as to why hydrogen in a carbon film retards the increase in friction is that hydrogen-doped films exhibit a greater degree of elasticity. (Experimental data pertaining to this effect is provided below.) Thus, the carbon film is more compliant (elastic), and may be able to absorb the shock loading of the film by the read/write head, thereby allowing the film to last longer.
The hydrogen introduced at targets 8a, 8b is actually incorporated into the sputtered carbon film. This was demonstrated by using a sampling gas mass spectrometer or residual gas analyzer (RGA) to monitor the consumption rate of hydrogen near the carbon sputtering targets. A plot of the hydrogen mass peak intensity versus calculated hydrogen concentration with the plasma on and off (i.e. when sputtering is taking place and not taking place, respectively) is shown in FIG. 7. The RGA output is in arbitrary units, but is proportional to the amount of hydrogen in the sputtering chamber near targets 8a, 8b. From this data, it can be determined that plasma at the carbon targets consumes approximately one half of the hydrogen introduced at the carbon cathode area, indicating that the plasma causes reaction of input hydrogen and results in incorporation of hydrogen into the carbon film. (Unless otherwise stated, hydrogen concentrations elsewhere in this specification and claims refer to concentrations calculated as if there were no hydrogen consumption during sputtering. It is believed, however, that the hydrogen concentration is about 50% of this calculated value at targets 8a, 8b when the plasma is on.)
Raman spectroscopy is a useful technique for obtaining information regarding the bonding characteristics of carbon atoms within the deposited film. See D. S. Knight, et al., "Characterization of Diamond Films", J. Mater. Res. Vol 4, No. 2, March/April 1989, and Willard et al., Instrumental Methods of Analysis, 6th Edition, published by Wadsworth Publishing Co. in 1981, incorporated herein by reference. Typical spectra of a carbon film with no hydrogen is shown in FIG. 8A. Typically the spectra is characterized by broad overlapping peaks around 1310/cm (generally known as the D-peak) and 1550/cm (generally known as the G-peak). The peaks can be deconvoluted to obtain more accurate peak position and intensity values. The deconvoluted spectra is shown in FIG. 8B. The Raman spectra of a film produced using 80 SCCM of the 20% H 2 /80% argon mixture is shown in FIG. 8C. There is a change in the ratio of the D to G peaks, as well as a slight shift in the peak positions as seen in the deconvoluted spectra of FIG. 8C, shown in FIG. 8D. The G and D peaks shift to lower frequencies as hydrogen is added. The change in peak ratio expressed in terms of height and area ratios as a function of the amount of hydrogen present during sputtering is plotted in FIG. 9, and height position is plotted in FIG. 10. Raman spectra shows a clear indication of the changes in chemistry of the carbon atoms within the film as more hydrogen is added. Based on changes in the SP3/SP2 peak intensity ratios, it is apparent that the carbon becomes more amorphous.
Typically, a carbon film lacking hydrogen has a brown to greyish color at a thickness of about 300 Å. The sheet resistance at this thickness is about 0.5MΩ/square, using a four point probe measurement. Resistivity of a 300 Å carbon film made with 20 SCCM of the 20% hydrogen/80% argon mixture was measured using a four point probe. The resistance was greater than 20MΩ/square. Further, the carbon film sputtered with 20 SCCM 20% H 2 /80% argon was yellow when formed on a metallic alloy, and colorless if formed on glass. This indicates that hydrogen in the sputtering chamber introduces chemical and structural changes in the resulting carbon film.
A specially made 2000 Å thick carbon coating was made in order that micro-hardness measurements can be taken of the carbon coating with various amounts of hydrogen. The method used for the hardness and elastic constant determination is described by M. F. Doerner et al. in "A Method For Interpreting The Data From Depth-Sensing Indentation Instruments", published in J. Mater. Res., July/August 1986, p. 601. Table 1 below lists the values which were obtained.
______________________________________Flow Rate of the20% Hydrogen/80% Armixture Hardness Elasticity______________________________________ 0 SCCM 8 GPa 140 GPa60 SCCM 8 GPa 92 GPa90 SCCM 8 GPa 85 GPa______________________________________
As can be seen, the hardness of the film does not change as more hydrogen is added. However, the elastic constant decreases drastically. The film becomes less stiff as more hydrogen is added. As mentioned above, this may explain the difference in wear.
From measurements of chemical, electrical, optical and mechanical properties it is clear that there is a significant change in the sputtered carbon film as high concentration of hydrogen is introduced into the plasma during deposition. It is strongly believed that consumption of hydrogen by the plasma as measured by residual gas analyzer clearly indicates incorporation of hydrogen into the carbon film. The large improvement in the mechanical performance of the carbon film as measured by continuous friction test occurs at a concentration of hydrogen at the carbon cathode of about 15% of the total gas present.
Although the above-described process uses H 2 , in other embodiments, gaseous compounds containing hydrogen, such as H 2 O and NH 3 , can be used in sputtering chamber 5. Such compounds decompose during sputtering and the hydrogen from the compound dopes the carbon film. Further, hydrogen or a gaseous compound containing hydrogen can be mixed with inert gases other than argon.
While the invention has been described with respect to specific embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. For example, a liquid or solid lubricant can be applied to the carbon layer after sputtering to further enhance mechanical performance. In addition, an intermediate layer may be provided between the magnetic alloy and the carbon film. The disk can be textured in a conventional manner to further reduce friction. Also, substrates other than aluminum, e.g. glass, may be used. Accordingly, all such changes come within the present invention. | A carbon film for protecting a magnetic disk is sputtered in the presence of hydrogen. If a sufficient amount of hydrogen is present in the sputtering chamber, the resulting carbon film will exhibit superior mechanical characteristics, i.e. an enhanced wear resistance during a contact-start-stop or drag test in a disk drive. Sputtering in the presence of hydrogen can be accomplished by either DC or RF magnetron sputtering, or DC or RF diode sputtering. | 8 |
The present application is a continuation-in-part of U.S. patent application Ser. No. 13/270,840 filed Oct. 11, 2011. U.S. patent application Ser. No. 13/270,840 is a continuation of U.S. patent application Ser. No. 13/035,777 filed Feb. 25, 2011. U.S. patent application Ser. No. 13/035,777 claims the benefit of priority of U.S. Provisional Application No. 61/308,884, filed Feb. 26, 2010, and is also a continuation-in-part of International Patent Application No. PCT/US09/68818, filed Dec. 18, 2009. International Patent Application No. PCT/US09/68818 claims the benefit of priority of U.S. Provisional Application 61/139,470, filed Dec. 19, 2008. The present application also claims the benefit of priority of U.S. Provisional Patent Application No. 61/678,458 filed Aug. 1, 2012.
STATEMENT OF GOVERNMENT INTEREST
This invention was made with Government support under R21EY018491 awarded by the National Institutes of Health (NIH)/National Eye Institute (NEI), under R21NS064328, awarded by the NIH/National Institute of Neurological Disorders and Stroke (NINDS) and under RC2 NS69476-01 awarded by the National Institutes of Health (NIH). The Government has certain rights in the invention.
INCORPORATION BY REFERENCE OF THE SEQUENCE LISTING
This application contains, as a separate part of disclosure, a Sequence Listing in computer-readable form (filename: 44125CIP_SubSeqListing.txt; 21,551 bytes; created Jun. 4, 2014—ASCII text file) which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The present invention relates to Adeno-associated virus 9 methods and materials useful for systemically delivering polynucleotides across the blood brain barrier. Accordingly, the present invention also relates to methods and materials useful for systemically delivering polynucleotides to the central and peripheral nervous systems. The present invention also relates to Adeno-associated virus type 9 methods and materials useful for intrathecal delivery (i.e., delivery into the space under the arachnoid membrane of the brain or spinal cord) of polynucleotides. Use of the methods and materials is indicated, for example, for treatment of lower motor neuron diseases such as spinal muscle atrophy and amyotrophic lateral sclerosis as well as Pompe disease and lysosomal storage disorders. Use of the methods and materials is also indicated, for example, for treatment of Rett syndrome.
BACKGROUND
Large-molecule drugs do not cross the blood-brain-barrier (BBB) and 98% of small-molecules cannot penetrate this barrier, thereby limiting drug development efforts for many CNS disorders [Pardridge, W. M. Nat Rev Drug Discov 1: 131-139 (2002)]. Gene delivery has recently been proposed as a method to bypass the BBB [Kaspar, et al., Science 301: 839-842 (2003)]; however, widespread delivery to the brain and spinal cord has been challenging. The development of successful gene therapies for motor neuron disease will likely require widespread transduction within the spinal cord and motor cortex. Two of the most common motor neuron diseases are spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), both debilitating disorders of children and adults, respectively, with no effective therapies to date. Recent work in rodent models of SMA and ALS involves gene delivery using viruses that are retrogradely transported following intramuscular injection [Kaspar et al., Science 301: 839-842 (2003); Azzouz et al., J Clin Invest 114: 1726-1731 (2004); Azzouz et al., Nature 429: 413-417 (2004); Ralph et al., Nat Med 11: 429-433 (2005)]. However, clinical development may be difficult given the numerous injections required to target the widespread region of neurodegeneration throughout the spinal cord, brainstem and motor cortex to effectively treat these diseases. Adeno-associated virus (AAV) vectors have also been used in a number of recent clinical trials for neurological disorders, demonstrating sustained transgene expression, a relatively safe profile, and promising functional responses, yet have required surgical intraparenchymal injections [Kaplitt et al., Lancet 369: 2097-2105 (2007); Marks et al., Lancet Neurol 7: 400-408 (2008); Worgall et al., Hum Gene Ther (2008)].
SMA is an early pediatric neurodegenerative disorder characterized by flaccid paralysis within the first six months of life. In the most severe cases of the disease, paralysis leads to respiratory failure and death usually by two years of age. SMA is the second most common pediatric autosomal recessive disorder behind cystic fibrosis with an incidence of 1 in 6000 live births. SMA is a genetic disorder characterized by the loss of lower motor neurons (LMNs) residing along the length of the entire spinal cord. SMA is caused by a reduction in the expression of the survival motor neuron (SMN) protein that results in denervation of skeletal muscle and significant muscle atrophy. SMN is a ubiquitously expressed protein that functions in U snRNP biogenesis.
In humans there are two very similar copies of the SMN gene termed SMN1 and SMN2. The amino acid sequence encoded by the two genes is identical. However, there is a single, silent nucleotide change in SMN2 in exon 7 that results in exon 7 being excluded in 80-90% of transcripts from SMN2. The resulting truncated protein, called SMNA7, is less stable and rapidly degraded. The remaining 10-20% of transcript from SMN2 encodes the full length SMN protein. Disease results when all copies of SMN1 are lost, leaving only SMN2 to generate full length SMN protein. Accordingly, SMN2 acts as a phenotypic modifier in SMA in that patients with a higher SMN2 copy number generally exhibit later onset and less severe disease.
To date, there are no effective therapies for SMA. Therapeutic approaches have mainly focused on developing drugs for increasing SMN levels or enhancing residual SMN function. Despite years of screening, no drugs have been fully effective for increasing SMN levels as a restorative therapy. A number of mouse models have been developed for SMA. See, Hsieh-Li et al., Nature Genetics, 24 (1): 66-70 (2000); Le et al., Hum. Mol. Genet., 14 (6): 845-857 (2005); Monani et al., J. Cell. Biol., 160 (1): 41-52 (2003) and Monani et al., Hum. Mol. Genet., 9 (3): 333-339 (2000). A recent study express a full length SMN cDNA in a mouse model and the authors concluded that expression of SMN in neurons can have a significant impact on symptoms of SMA. See Gavrilina et al., Hum. Mol. Genet., 17(8):1063-1075 (2008).
ALS is another disease that results in loss of muscle and/or muscle function. First characterized by Charcot in 1869, it is a prevalent, adult-onset neurodegenerative disease affecting nearly 5 out of 100,000 individuals. ALS occurs when specific nerve cells in the brain and spinal cord that control voluntary movement gradually degenerate. Within two to five years after clinical onset, the loss of these motor neurons leads to progressive atrophy of skeletal muscles, which results in loss of muscular function resulting in paralysis, speech deficits, and death due to respiratory failure.
The genetic defects that cause or predispose ALS onset are unknown, although missense mutations in the SOD-1 gene occurs in approximately 10% of familial ALS cases, of which up to 20% have mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1), located on chromosome 21. SOD-1 normally functions in the regulation of oxidative stress by conversion of free radical superoxide anions to hydrogen peroxide and molecular oxygen. To date, over 90 mutations have been identified spanning all exons of the SOD-1 gene. Some of these mutations have been used to generate lines of transgenic mice expressing mutant human SOD-1 to model the progressive motor neuron disease and pathogenesis of ALS.
De novo mutations in the X-linked gene encoding the transcription factor, Methyl-CpG binding protein 2 (MECP2), are the most frequent cause of the neurological disorder Rett syndrome (RTT). Hemizygous males usually die of neonatal encephalopathy. Heterozygous females survive into adulthood but exhibit severe symptoms including microcephaly, loss of purposeful hand motions and speech, and motor abnormalities which appear following a period of apparently normal development. Both male and female mouse models exhibit RTT-like behaviors [Guy et al., Nature Genetics, 27: 322-326 (2001); Chen et al., Nature Genetics 27: 327-331 (2001); and Katz et al., 5: 733-745 (2012)], but most studies have focused on males because of the shorter latency to and severity in symptoms. Despite encouraging studies on male mice, no therapeutic treatment has been shown yet to be effective in females, the more gender appropriate model.
AAV is a replication-deficient parvovirus, the single-stranded DNA genome of which is about 4.7 kb in length including 145 nucleotide inverted terminal repeat (ITRs). The nucleotide sequence of the AAV serotype 2 (AAV2) genome is presented in Srivastava et al., J Virol, 45: 555-564 (1983) as corrected by Ruffing et al., J Gen Virol, 75: 3385-3392 (1994). Cis-acting sequences directing viral DNA replication (rep), encapsidation/packaging and host cell chromosome integration are contained within the ITRs. Three AAV promoters (named p5, p19, and p40 for their relative map locations) drive the expression of the two AAV internal open reading frames encoding rep and cap genes. The two rep promoters (p5 and p19), coupled with the differential splicing of the single AAV intron (at nucleotides 2107 and 2227), result in the production of four rep proteins (rep 78, rep 68, rep 52, and rep 40) from the rep gene. Rep proteins possess multiple enzymatic properties that are ultimately responsible for replicating the viral genome. The cap gene is expressed from the p40 promoter and it encodes the three capsid proteins VP1, VP2, and VP3. Alternative splicing and non-consensus translational start sites are responsible for the production of the three related capsid proteins. A single consensus polyadenylation site is located at map position 95 of the AAV genome. The life cycle and genetics of AAV are reviewed in Muzyczka, Current Topics in Microbiology and Immunology, 158: 97-129 (1992).
AAV possesses unique features that make it attractive as a vector for delivering foreign DNA to cells, for example, in gene therapy. AAV infection of cells in culture is noncytopathic, and natural infection of humans and other animals is silent and asymptomatic. Moreover, AAV infects many mammalian cells allowing the possibility of targeting many different tissues in vivo. Moreover, AAV transduces slowly dividing and non-dividing cells, and can persist essentially for the lifetime of those cells as a transcriptionally active nuclear episome (extrachromosomal element). The AAV proviral genome is infectious as cloned DNA in plasmids which makes construction of recombinant genomes feasible. Furthermore, because the signals directing AAV replication, genome encapsidation and integration are contained within the ITRs of the AAV genome, some or all of the internal approximately 4.3 kb of the genome (encoding replication and structural capsid proteins, rep-cap) may be replaced with foreign DNA such as a gene cassette containing a promoter, a DNA of interest and a polyadenylation signal. The rep and cap proteins may be provided in trans. Another significant feature of AAV is that it is an extremely stable and hearty virus. It easily withstands the conditions used to inactivate adenovirus (56° to 65° C. for several hours), making cold preservation of AAV less critical. AAV may even be lyophilized. Finally, AAV-infected cells are not resistant to superinfection.
Multiple serotypes of AAV exist and offer varied tissue tropism. Known serotypes include, for example, AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10 and AAV11. AAV9 is described in U.S. Pat. No. 7,198,951 and in Gao et al., J. Virol., 78: 6381-6388 (2004). Advances in the delivery of AAV6 and AAV8 have made possible the transduction by these serotypes of skeletal and cardiac muscle following simple systemic intravenous or intraperitoneal injections. See Pacak et al., Circ. Res., 99(4): 3-9 (1006) and Wang et al., Nature Biotech., 23(3): 321-8 (2005). The use of AAV to target cell types within the central nervous system, though, has required surgical intraparenchymal injection. See, Kaplitt et al., supra; Marks et al., supra and Worgall et al., supra.
There thus remains a need in the art for methods and vectors for delivering genes across the BBB.
SUMMARY
The present invention provides methods and materials useful for systemically delivering polynucleotides across the BBB. The present invention also provides methods and materials useful for intrathecal delivery of polynucleotides to the central nervous system.
In one aspect, the invention provides methods of delivering a polynucleotide across the BBB comprising systemically administering a recombinant AAV9 (rAAV9) with a genome including the polynucleotide to a patient. In some embodiments, the rAAV9 genome is a self complementary genome. In other embodiments, the rAAV9 genome is a single-stranded genome.
In some embodiments, the methods systemically deliver polynucleotides across the BBB to the central and/or peripheral nervous system. Accordingly, a method is provided of delivering a polynucleotide to the central nervous system comprising systemically administering a rAAV9 with a self-complementary genome including the genome to a patient. In some embodiments, the polynucleotide is delivered to brain. In some embodiments, the polynucleotide is delivered to the spinal cord. Also provided is a method of delivering a polynucleotide to the peripheral nervous system comprising systemically administering a rAAV9 with a self-complementary genome including the polynucleotide to a patient is provided. In some embodiments, the polynucleotide is delivered to a lower motor neuron.
In another aspect, the invention provides methods of delivering a polynucleotide to the central nervous system of a patient in need thereof comprising intrathecal delivery of rAAV9 with a genome including the polynucleotide. In some embodiments, rAAV9 genome is a self-complementary genome. In some embodiments, a non-ionic, low-osmolar contrast agent is also delivered to the patient, for example, iobitridol, iohexol, iomeprol, iopamidol, iopentol, iopromide, ioversol or ioxilan.
Embodiments of the invention employ rAAV9 to deliver polynucleotides to nerve and glial cells. In some aspects, the glial cell is a microglial cell, an oligodendrocyte or an astrocyte. In other aspects the rAAV9 is used to deliver a polynucleotide to a Schwann cell.
Use of the systemic or intrathecal delivery methods is indicated, for example, for lower motor neuron diseases such as SMA and ALS as well as Pompe disease, lysosomal storage disorders, Glioblastoma multiforme and Parkinson's disease. Lysosomal storage disorders include, but are not limited to, Activator Deficiency/GM2 Gangliosidosis, Alpha-mannosidosis, Aspartylglucosaminuria, Cholesteryl ester storage disease, Chronic Hexosaminidase A Deficiency, Cystinosis, Danon disease, Fabry disease, Farber disease, Fucosidosis, Galactosialidosis, Gaucher Disease (Type I, Type II, Type III), GM1 gangliosidosis (Infantile, Late infantile/Juvenile, Adult/Chronic), I-Cell disease/Mucolipidosis II, Infantile Free Sialic Acid Storage Disease/ISSD, Juvenile Hexosaminidase A Deficiency, Krabbe disease (Infantile Onset, Late Onset), Metachromatic Leukodystrophy, Mucopolysaccharidoses disorders (Pseudo-Hurler polydystrophy/Mucolipidosis IIIA, MPSI Hurler Syndrome, MPSI Scheie Syndrome, MPS I Hurler-Scheie Syndrome, MPS II Hunter syndrome, Sanfilippo syndrome Type A/MPS III A, Sanfilippo syndrome Type B/MPS III B, Sanfilippo syndrome Type C/MPS III C, Sanfilippo syndrome Type D/MPS III D, Morquio Type A/MPS IVA, Morquio Type B/MPS IVB, MPS IX Hyaluronidase Deficiency, MPS VI Maroteaux-Lamy, MPS VII Sly Syndrome, Mucolipidosis I/Sialidosis, Mucolipidosis IIIC, Mucolipidosis type IV), Multiple sulfatase deficiency, Niemann-Pick Disease (Type A, Type B, Type C), Neuronal Ceroid Lipofuscinoses (CLN6 disease (Atypical Late Infantile, Late Onset variant, Early Juvenile), Batten-Spielmeyer-Vogt/Juvenile NCL/CLN3 disease, Finnish Variant Late Infantile CLN5, Jansky-Bielschowsky disease/Late infantile CLN2/TPP1 Disease, Kufs/Adult-onset NCL/CLN4 disease, Northern Epilepsy/variant late infantile CLN8, Santavuori-Haltia/Infantile CLN1/PPT disease, Beta-mannosidosis, Pompe disease/Glycogen storage disease type II, Pycnodysostosis, Sandhoff Disease/Adult Onset/GM2 Gangliosidosis, Sandhoff Disease/GM2 gangliosidosis—Infantile, Sandhoff Disease/GM2 gangliosidosis—Juvenile, Schindler disease, Salla disease/Sialic Acid Storage Disease, Tay-Sachs/GM2 gangliosidosis, Wolman disease.
In further embodiments, use of the systemic or intrathecal delivery methods is indicated for treatment of nervous system disease such as Rett Syndrome, Alzheimer's Disease, Parkinson's Disease, Huntington's Disease along with nervous system injury including spinal cord and brain trauma/injury, stroke, and brain cancers. In some embodiments, methods of treatment of Rett syndrome are contemplated where the methods deliver a polynucleotide to the central nervous system of a patient in need thereof by systemic delivery of rAAV9 with a genome including the polynucleotide. In some embodiments, methods of treatment of Rett syndrome are contemplated where the methods deliver a polynucleotide to the central nervous system of a patient in need thereof by intrathecal delivery of rAAV9 with a genome including the polynucleotide.
In yet another aspect, the invention provides rAAV genomes. The rAAV genomes comprise one or more AAV ITRs flanking a polynucleotide encoding a polypeptide (including, but not limited to, an SMN polypeptide) or encoding short hairpin RNAs directed at mutated proteins or control sequences of their genes. The polynucleotide is operatively linked to transcriptional control DNAs, specifically promoter DNA and polyadenylation signal sequence DNA that are functional in target cells to form a gene cassette. The gene cassette may also include intron sequences to facilitate processing of an RNA transcript when expressed in mammalian cells.
In some aspects, the rAAV9 genome encodes a trophic or protective factor. In various embodiments, use of a trophic or protective factor is indicated for neurodegenerative disorders contemplated herein, including but not limited to Alzheimer's Disease, Parkinson's Disease, Huntington's Disease along with nervous system injury including spinal cord and brain trauma/injury, stroke, and brain cancers. Non-limiting examples of known nervous system growth factors include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT-4/5), neurotrophin-6 (NT-6), ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), the fibroblast growth factor family (e.g., FGF's 1-15), leukemia inhibitory factor (LIF), certain members of the insulin-like growth factor family (e.g., IGF-1), the neurturins, persephin, the bone morphogenic proteins (BMPs), the immunophilins, the transforming growth factor (TGF) family of growth factors, the neuregulins, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor family (e.g. VEGF 165), follistatin, Hif1, and others. Also generally contemplated are zinc finger transcription factors that regulate each of the trophic or protective factors contemplated herein. In further embodiments, methods to modulate neuro-immune function are contemplated, including but not limited to, inhibition of microglial and astroglial activation through, for example, NFkB inhibition, or NFkB for neuroprotection (dual action of NFkB and associated pathways in different cell types) by siRNA, shRNA, antisense, or miRNA. In still further embodiments, the rAAV9 genome encodes an apoptotic inhibitor (e.g., bcl2, bclxL). Use of a rAAV9 encoding a trophic factor or spinal cord injury modulating protein or a suppressor of an inhibitor of axonal growth (e.g., a suppressor of Nogo [Oertle et al., The Journal of Neuroscience, 23(13):5393-5406 (2003)] is also contemplated for treating spinal cord injury.
In some embodiments, use of materials and methods of the invention is indicated for neurodegenerative disorders such as Parkinson's disease. In various embodiments, the rAAV9 genome may encode, for example, Aromatic acid dopa decarboxylase (AADC), Tyrosine hydroxylase, GTP-cyclohydrolase 1 (gtpch1), apoptotic inhibitors (e.g., bcl2, bclxL), glial cell line-derived neurotrophic factor (GDNF), the inhibitory neurotransmitter-amino butyric acid (GABA), and enzymes involved in dopamine biosynthesis. In further embodiments, the rAAV9 genome may encode, for example, modifiers of Parkin and/or synuclein.
In some embodiments, use of materials and methods of the invention is indicated for neurodegenerative disorders such as Alzheimer's disease. In further embodiments, methods to increase acetylcholine production are contemplated. In still further embodiments, methods of increasing the level of a choline acetyltransferase (ChAT) or inhibiting the activity of an acetylcholine esterase (AchE) are contemplated.
In some embodiments, the rAAV9 genome may encode, for example, methods to decrease mutant Huntington protein (htt) expression through siRNA, shRNA, antisense, and/or miRNA for treating a neurodegenerative disorder such as Huntington's disease.
In some embodiments, use of materials and methods of the invention is indicated for neurodegenerative disorders such as ALS. In some aspects, treatment with the embodiments contemplated by the invention results in a decrease in the expression of molecular markers of disease, such as TNFα, nitric oxide, peroxynitrite, and/or nitric oxide synthase (NOS).
In other aspects, the vectors could encode short hairpin RNAs directed at mutated proteins such as superoxide dismutase for ALS, or neurotrophic factors such as GDNF or IGF1 for ALS or Parkinson's disease.
In some embodiments, use of materials and methods of the invention is indicated for preventing or treating neurodevelopmental disorders such as Rett Syndrome. For embodiments relating to Rett Syndrome, the rAAV9 genome may encode, for example, methyl cytosine binding protein 2 (MECP2).
The rAAV genomes of the invention lack AAV rep and cap DNA. AAV DNA in the rAAV genomes (e.g., ITRs) may be from any AAV serotype for which a recombinant virus can be derived including, but not limited to, AAV serotypes AAV-1, AAV-2, AAV-3, AAV-4, AAV-5, AAV-6, AAV-7, AAV-8, AAV-9, AAV-10 and AAV-11. The nucleotide sequences of the genomes of the AAV serotypes are known in the art. For example, the complete genome of AAV-1 is provided in GenBank Accession No. NC_002077; the complete genome of AAV-2 is provided in GenBank Accession No. NC_001401 and Srivastava et al., J. Virol., 45: 555-564 {1983); the complete genome of AAV-3 is provided in GenBank Accession No. NC_1829; the complete genome of AAV-4 is provided in GenBank Accession No. NC_001829; the AAV-5 genome is provided in GenBank Accession No. AF085716; the complete genome of AAV-6 is provided in GenBank Accession No. NC_00 1862; at least portions of AAV-7 and AAV-8 genomes are provided in GenBank Accession Nos. AX753246 and AX753249, respectively; the AAV-9 genome is provided in Gao et al., J. Virol., 78: 6381-6388 (2004); the AAV-10 genome is provided in Mol. Ther., 13(1): 67-76 (2006); and the AAV-11 genome is provided in Virology, 330(2): 375-383 (2004).
In another aspect, the invention provides DNA plasmids comprising rAAV genomes of the invention. The DNA plasmids are transferred to cells permissible for infection with a helper virus of AAV (e.g., adenovirus, E1-deleted adenovirus or herpesvirus) for assembly of the rAAV genome into infectious viral particles. Techniques to produce rAAV particles, in which an AAV genome to be packaged, rep and cap genes, and helper virus functions are provided to a cell are standard in the art. Production of rAAV requires that the following components are present within a single cell (denoted herein as a packaging cell): a rAAV genome, AAV rep and cap genes separate from (i.e., not in) the rAAV genome, and helper virus functions. The AAV rep and cap genes may be from any AAV serotype for which recombinant virus can be derived and may be from a different AAV serotype than the rAAV genome ITRs, including, but not limited to, AAV serotypes AAV-1, AAV-2, AAV-3, AAV-4, AAV-5, AAV-6, AAV-7, AAV-8, AAV-9, AAV-10 and AAV-11. Production of pseudotyped rAAV is disclosed in, for example, WO 01/83692 which is incorporated by reference herein in its entirety. In various embodiments, AAV capsid proteins may be modified to enhance delivery of the recombinant vector. Modifications to capsid proteins are generally known in the art. See, for example, US 20050053922 and US 20090202490, the disclosures of which are incorporated by reference herein in their entirety.
A method of generating a packaging cell is to create a cell line that stably expresses all the necessary components for AAV particle production. For example, a plasmid (or multiple plasmids) comprising a rAAV genome lacking AAV rep and cap genes, AAV rep and cap genes separate from the rAAV genome, and a selectable marker, such as a neomycin resistance gene, are integrated into the genome of a cell. AAV genomes have been introduced into bacterial plasmids by procedures such as GC tailing (Samulski et al., 1982, Proc. Natl. Acad. S6. USA, 79:2077-2081), addition of synthetic linkers containing restriction endonuclease cleavage sites (Laughlin et al., 1983, Gene, 23:65-73) or by direct, blunt-end ligation (Senapathy & Carter, 1984, J. Biol. Chem., 259:4661-4666). The packaging cell line is then infected with a helper virus such as adenovirus. The advantages of this method are that the cells are selectable and are suitable for large-scale production of rAAV. Other examples of suitable methods employ adenovirus or baculovirus rather than plasmids to introduce rAAV genomes and/or rep and cap genes into packaging cells.
General principles of rAAV production are reviewed in, for example, Carter, 1992, Current Opinions in Biotechnology, 1533-539; and Muzyczka, 1992, Curr. Topics in Microbial. and Immunol., 158:97-129). Various approaches are described in Ratschin et al., Mol. Cell. Biol. 4:2072 (1984); Hermonat et al., Proc. Natl. Acad. Sci. USA, 81:6466 (1984); Tratschin et al., Mol. Cell. Biol. 5:3251 (1985); McLaughlin et al., J. Virol., 62:1963 (1988); and Lebkowski et al., 1988 Mol. Cell. Biol., 7:349 (1988). Samulski et al. (1989, J. Virol., 63:3822-3828); U.S. Pat. No. 5,173,414; WO 95/13365 and corresponding U.S. Pat. No. 5,658,776; WO 95/13392; WO 96/17947; PCT/US98/18600; WO 97/09441 (PCT/US96/14423); WO 97/08298 (PCT/US96/13872); WO 97/21825 (PCT/US96/20777); WO 97/06243 (PCT/FR96/01064); WO 99/11764; Perrin et al. (1995) Vaccine 13:1244-1250; Paul et al. (1993) Human Gene Therapy 4:609-615; Clark et al. (1996) Gene Therapy 3:1124-1132; U.S. Pat. No. 5,786,211; U.S. Pat. No. 5,871,982; and U.S. Pat. No. 6,258,595. Single-stranded rAAV are specifically contemplated. The foregoing documents are hereby incorporated by reference in their entirety herein, with particular emphasis on those sections of the documents relating to rAAV production.
The invention thus provides packaging cells that produce infectious rAAV. In one embodiment packaging cells may be stably transformed cancer cells such as HeLa cells, 293 cells and PerC.6 cells (a cognate 293 line). In another embodiment, packaging cells are cells that are not transformed cancer cells such as low passage 293 cells (human fetal kidney cells transformed with E1 of adenovirus), MRC-5 cells (human fetal fibroblasts), WI-38 cells (human fetal fibroblasts), Vero cells (monkey kidney cells) and FRhL-2 cells (rhesus fetal lung cells).
In still another aspect, the invention provides rAAV (i.e., infectious encapsidated rAAV particles) comprising a rAAV genome of the invention. In some embodiments, the rAAV genome is a self-complementary genome.
In some embodiments, the invention includes, but is not limited to, the exemplified rAAV named “rAAV SMN.” The rAAV SMN genome has in sequence an AAV2 ITR, the chicken β-actin promoter with a cytomegalovirus enhancer, an SV40 intron, the SMN coding DNA set out in SEQ ID NO: 1 (GenBank Accession Number NM_000344.2), a polyadenylation signal sequence from bovine growth hormone and another AAV2 ITR. Conservative nucleotide substitutions of SMN DNA are also contemplated (e.g., a guanine to adenine change at position 625 of GenBank Accession Number NM_000344.2). The genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome. SMN polypeptides contemplated include, but are not limited to, the human SMN1 polypeptide set out in NCBI protein database number NP_000335.1. Also contemplated is the SMN1-modifier polypeptide plastin-3 (PLS3) [Oprea et al., Science 320(5875): 524-527 (2008)]. Sequences encoding other polypeptides may be substituted for the SMN DNA.
Other rAAV9 are provided such as a rAAV9 named “scAAV9 MECP2.” Its genome has in sequence an AAV2 ITR missing the terminal resolution site, an approximately 730 bp murine MECP2 promoter fragment, SV40 intron sequences, murine MECP2 coding sequences, a bovine growth hormone polyadenylation signal sequence and an AAV2 ITR. The scAAV9 MECP2 genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome. Yet another rAAV9 provided is a rAAV9 named “scAAV9 hMECP2.” Its genome has in sequence an AAV2 ITR missing the terminal resolution site, an approximately 730 bp murine MECP2 promoter fragment, SV40 intron sequences, human MECP2α coding sequences, a bovine growth hormone polyadenylation signal sequence and an AAV2 ITR. The scAAV9 hMECP2 genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome. Substitution of human MECP2 promoter sequences for the corresponding murine MECP2 promoter sequences is specifically contemplated.
The rAAV of the invention may be purified by methods standard in the art such as by column chromatography or cesium chloride gradients. Methods for purifying rAAV vectors from helper virus are known in the art and include methods disclosed in, for example, Clark et al., Hum. Gene Ther., 10(6): 1031-1039 (1999); Schenpp and Clark, Methods Mol. Med., 69 427-443 (2002); U.S. Pat. No. 6,566,118 and WO 98/09657.
In another aspect, the invention contemplates compositions comprising rAAV of the present invention. In one embodiment, compositions of the invention comprise a rAAV encoding a SMN polypeptide. In another embodiment, compositions of the invention comprise a rAAV encoding a MECP2 polypeptide. In other embodiments, compositions of the present invention may include two or more rAAV encoding different polypeptides of interest.
Compositions of the invention comprise rAAV in a pharmaceutically acceptable carrier. The compositions may also comprise other ingredients such as diluents and adjuvants. Acceptable carriers, diluents and adjuvants are nontoxic to recipients and are preferably inert at the dosages and concentrations employed, and include buffers such as phosphate, citrate, or other organic acids; antioxidants such as ascorbic acid; low molecular weight polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as Tween, pluronics or polyethylene glycol (PEG).
Titers of rAAV to be administered in methods of the invention will vary depending, for example, on the particular rAAV, the mode of administration, the treatment goal, the individual, and the cell type(s) being targeted, and may be determined by methods standard in the art. Titers of rAAV may range from about 1×10 6 , about 1×10 7 , about 1×10 8 , about 1×10 9 , about 1×10 10 , about 1×10 11 , about 1×10 12 , about 1×10 13 to about 1×10 14 or more DNase resistant particles (DRP) per ml. Dosages may also be expressed in units of viral genomes (vg). Dosages may also vary based on the timing of the administration to a human. These dosages of rAAV may range from about 1×10 11 vg/kg, about 1×10 12 , about 1×10 13 , about 1×10 14 , about 1×10 15 , about 1×10 16 or more viral genomes per kilogram body weight in an adult. For a neonate, the dosages of rAAV may range from about 1×10 11 , about 1×10 12 , about 3×10 12 , about 1×10 13 , about 3×10 13 , about 1×10 14 , about 3×10 14 , about 1×10 15 , about 3×10 15 , about 1×10 16 , about 3×10 16 or more viral genomes per kilogram body weight.
Methods of transducing nerve or glial target cells with rAAV are contemplated by the invention. The methods comprise the step of administering an intravenous or intrathecal effective dose, or effective multiple doses, of a composition comprising a rAAV of the invention to an animal (including a human being) in need thereof. If the dose is administered prior to development of a disorder/disease, the administration is prophylactic. If the dose is administered after the development of a disorder/disease, the administration is therapeutic. In embodiments of the invention, an effective dose is a dose that alleviates (eliminates or reduces) at least one symptom associated with the disorder/disease state being treated, that slows or prevents progression to a disorder/disease state, that slows or prevents progression of a disorder/disease state, that diminishes the extent of disease, that results in remission (partial or total) of disease, and/or that prolongs survival. Examples of disease states contemplated for treatment by methods of the invention are listed herein above.
Combination therapies are also contemplated by the invention. Combination as used herein includes both simultaneous treatment or sequential treatments. Combinations of methods of the invention with standard medical treatments (e.g., riluzole in ALS) are specifically contemplated, as are combinations with novel therapies.
Route(s) of administration and serotype(s) of AAV components of rAAV (in particular, the AAV ITRs and capsid protein) of the invention may be chosen and/or matched by those skilled in the art taking into account the infection and/or disease state being treated and the target cells/tissue(s).
In some embodiments, administration of the rAAV9 to the patient is contemplated to occur at postnatal day 1 (P1). In some embodiments, administration is contemplated to occur at P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, P23, P24, P25, P26, P27, P28, P29, P30, P31, P32, P33, P34, P35, P36, P37, P38, P39, P40, P41, P42, P43, P44, P45, P46, P47, P48, P49, P50, P51, P52, P53, P54, P55, P56, P57, P58, P59, P60, P61, P62, P63, P64, P65, P66, P67, P68, P69, P70, P71, P72, P73, P74, P75, P76, P77, P78, P79, P80, P81, P82, P83, P84, P85, P86, P87, P88, P89, P90, P91, P92, P93, P94, P95, P96, P97, P98, P99, P100, P110, P120, P130, P140, P150, P160, P170, P180, P190, P200, P250, P300, P350, 1 year, 1.5 years, 2 years, 2.5 years, 3 years or older. While delivery to an individual in need thereof after birth is contemplated, intrauteral delivery and delivery to the mother are also contemplated.
Compositions suitable for systemic or intrathecal use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases the form must be sterile and must be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating actions of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol and the like), suitable mixtures thereof, and vegetable oils. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of a dispersion and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal and the like. In many cases it will be preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by use of agents delaying absorption, for example, aluminum monostearate and gelatin, and Tween family of products (e.g., Tween 20).
Sterile injectable solutions are prepared by incorporating rAAV in the required amount in the appropriate solvent with various other ingredients enumerated above, as required, followed by filter sterilization. Generally, dispersions are prepared by incorporating the sterilized active ingredient into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and the freeze drying technique that yield a powder of the active ingredient plus any additional desired ingredient from the previously sterile-filtered solution thereof.
Transduction with rAAV may also be carried out in vitro. In one embodiment, desired target cells are removed from the subject, transduced with rAAV and reintroduced into the subject. Alternatively, syngeneic or xenogeneic cells can be used where those cells will not generate an inappropriate immune response in the subject.
Suitable methods for the transduction and reintroduction of transduced cells into a subject are known in the art. In one embodiment, cells can be transduced in vitro by combining rAAV with the cells, e.g., in appropriate media, and screening for those cells harboring the DNA of interest using conventional techniques such as Southern blots and/or PCR, or by using selectable markers. Transduced cells can then be formulated into pharmaceutical compositions, and the composition introduced into the subject by various techniques, such as by injection into the spinal cord.
Transduction of cells with rAAV of the invention results in sustained expression of polypeptide. The present invention thus provides methods of administering/delivering rAAV (e.g., encoding SMN protein or MECP2 protein) of the invention to an animal or a human patient. These methods include transducing nerve and/or glial cells with one or more rAAV of the present invention.
Transduction may also be carried out with gene cassettes comprising tissue specific control elements. For example, promoters that allow expression specifically within neurons or specifically within astrocytes. Examples include neuron specific enolase and glial fibrillary acidic protein promoters. Inducible promoters under the control of an ingested drug may also be developed (e.g., rapamycin). By way of non-limiting example, it is understood that systems such as the tetracycline (TET on/off) system [see, for example, Urlinger et al., Proc. Natl. Acad. Sci. USA 97(14):7963-7968 (2000) for recent improvements to the TET system] and Ecdysone receptor regulatable system [Palli et al., Eur J. Biochem 270: 1308-1315 (2003] may be utilized to provide inducible polynucleotide expression. It will also be understood by the skilled artisan that combinations of any of the methods and materials contemplated herein may be used for treating a neurodegenerative disease.
The term “transduction” is used to refer to the administration/delivery of a polynucleotide (e.g., SMN DNA or MECP2 DNA) to a recipient cell either in vivo or in vitro, via a replication-deficient rAAV of the invention resulting in expression of a functional polypeptide (e.g., SMN or MECP2) by the recipient cell.
Thus, the invention provides methods of administering an effective dose (or doses, administered essentially simultaneously or doses given at intervals) of rAAV of the invention to a patient in need thereof.
In still another aspect, methods of the invention may be used to deliver polynucleotides to a vascular endothelial cell rather than across the BBB.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts GFP expression in the gastrocnemius muscle of AAV9-GFP or PBS treated mice.
FIG. 2 depicts widespread neuron and astrocyte AAV9-GFP transduction in CNS and PNS 10-days-post-intravenous injection of P1 mice. (A-B) GFP and ChAT immunohistochemistry of cervical (A) and lumbar (B) spinal cord. (C) High-power magnification shows extensive co-localization of GFP and ChAT positive cells. (arrow indicates a GFP-positive astrocyte). (D) Neurons and astrocytes transduced in the hippocampus. (E) Pyramidal cells in the cortex were GFP positive. (F) Clusters of GFP positive astrocytes were observed throughout the brain. Scale bars (A-B) 200 μm, (C) 50 μm, (D-F) 50 μm.
FIG. 3 shows that intravenous injection of AAV9 leads to widespread neonatal spinal cord transduction. Cervical (a-c) and lumbar (e-k) spinal cord sections ten-days following facial-vein injection of 4×10 11 particles of scAAV9-CB-GFP into postnatal day-1 mice. GFP-expression (a,e,i) was predominantly restricted to lower motor neurons (a,e,i) and fibers that originated from dorsal root ganglia (a,e). GFP-positive astrocytes (i) were also observed scattered throughout the tissue sections. Lower motor neuron and astrocyte expression were confirmed by co-localization using choline acetyl transferase (ChAT) (b,f,j) and glial fibrillary acidic protein (GFAP) (c,g,k), respectively. A z-stack image (i-k) of the area within the box in h, shows the extent of motor neuron and astrocyte transduction within the lumbar spinal cord. Scale bars, 200 μm (d,h), 20 μm (l).
FIG. 4 shows that intravenous injection of AAV9 leads to widespread and long term neonatal spinal cord transduction in lumbar motor neurons. Z-series confocal microscopy showing GFP-expression in 21-day-old mice that received 4×10 11 particles of scAAV9-CB-GFP intravenous injections on postnatal day-1. Z-stack images of GFP (a), ChAT (b), GFAP (c) and merged (d) demonstrating persistent GFP-expression in motor neurons and astrocytes (d) for at least three-weeks following scAAV9-CB-GFP injection. Scale bar, 20 μm (d).
FIG. 5 depicts in situ hybridization of spinal cord sections from neonate and adult injected animals demonstrates that cells expressing GFP are transduced with scAAV9-CB-GFP. Negative control animals injected with PBS (a-b) showed no positive signal. However, antisense probes for GFP demonstrated strong positive signals for both neonate (c) and adult (e) sections analyzed. No positive signals were found for the sense control probe in neonate (d) or adult (f) spinal cord sections. Tissues were counterstained with Nuclear Fast Red for contrast while probe hybridization is in black.
FIG. 6 depicts cervical (A), thoracic (B) and lumbar (C) transverse sections from mouse spinal cord labeled for GFP and ChAT. The box in (C) denotes the location of (D-F). GFP (D), ChAT (E) and merged (F) images of transduced motor neurons in the lumbar spinal cord. In addition to motor neuron transductions, GFP positive fibers are seen in close proximity and overlapping motor neurons (D and F). Scale bars=(A-C) 200 μm and (F) 50 μm.
FIG. 7 depicts GFP (A), ChAT (B) and merged (C) images of a transverse section through lumbar spinal cord of a P10 mouse that had previously been injected at one day old with scAAV9 GFP. (D) represents a z-stack merged image of the ventral horn from (C). (E) shows that the scAAV9 vector resulted in more transduced motor neurons when compared to ssAAV9 vector in the lumbar spinal cord. Scale bars=(C) 100 μm and (D) 50 μm.
FIG. 8 depicts AAV9-GFP targeting of astrocytes in the spinal cord of adult-mice. (A-B) GFP immunohistochemistry in cervical (A) and lumbar (B) spinal cord demonstrating astrocyte transduction following tail-vein injection. (hatched-line indicates grey-white matter interface). (C) GFP and GFAP immunohistochemistry from lumbar spinal cord indicating astrocyte transduction. Scale bars (A-B) 100 μm, (C) 20 μm.
FIG. 9 shows that intravenous injection of AAV9 leads to widespread predominant astrocyte transduction in the spinal cord and brain of adult mice. GFP-expression in the cervical (a-c) and lumbar (e-g) spinal cord as well as the brain (m-o) of adult mice 7-weeks after tail vein injection of 4×10 12 particles of scAAV9-CB-GFP. In contrast to postnatal day-1 intravenous injections, adult tail vein injection resulted in almost exclusively astrocyte transduction. GFP (a,e), ChAT (b,f) and GFAP (c,g) demonstrate the abundance of GFPexpression throughout the spinal grey matter, with lack of co-localization with lower motor neurons and white matter astrocytes. Co-localization of GFP (i), excitatory amino acid transporter 2 (EAAT2) (j), and GFAP (k) confirm that transduced cells are astrocytes. Tail vein injection also resulted in primarily astrocyte transduction throughout the brain as seen in the cortex (m-n), thalamus (o) and midbrain. Neuronal GFP-expression in the brain was restricted to the hippocampus and dentate gyrus (m-n, FIG. 11 e - f ).
FIG. 10 depicts diagrams of coronal sections throughout the mouse brain corresponding to the approximate locations shown in ( FIG. 9 m - o ). The box in (a) corresponds to the location shown in ( FIG. 9 m ). The smaller box in (b) corresponds to ( FIG. 9 n ) and the larger box to ( FIG. 9 o ).
FIG. 11 depicts high-magnification of merged GFP and dapi images of brain regions following neonate (a-d) or adult (e-f) intravenous injection of scAAV9-CB-GFP. Astrocytes and neurons were easily detected in the striatum (a), hippocampus (b) and dentate gyrus (c) following postnatal day-1 intravenous injection of 4×10 11 particles of scAAV9-CB-GFP. Extensive GFP-expression within cerebellar Purkinje cells (d) was also observed. Pyramidal cells of the hippocampus (e) and granular cells of the dentate gyrus (f) were the only neuronal transduction within the brain following adult tail vein injection. In addition to astrocyte and neuronal transduction, widespread vascular transduction (f) was also seen throughout all adult brain sections examined. Scale bars, 200 μm (e); 100 μm (f), 50 μm (a-d).
FIG. 12 depicts widespread GFP-expression 21-days following intravenous injection of 4×10 11 particles of scAAV9-CB-GFP to postnatal day-1 mice. GFP localized in neurons and astrocytes throughout multiple structures of the brain as depicted in: (a) striatum (b) cingulate gyms (c) fornix and anterior commissure (d) internal capsule (e) corpus callosum (f) hippocampus and dentate gyrus (g) midbrain and (h) cerebellum. All panels show GFP and DAPI merged images. Schematic representations depicting the approximate locations of each image throughout the brain are shown in ( FIG. 13 ). Higher magnification images of select structures are available in ( FIG. 11, 14 ). Scale bars, 200 μm (a); 50 μm (e); 100 μm (b-d,f-h).
FIG. 13 depicts diagrams of coronal sections throughout the mouse brain. corresponding to the approximate locations shown in FIG. 12 ( a - h ) for postnatal day-1 injected neonatal mouse brains. The box in (a) corresponds to the location of ( FIG. 12 a ). The smaller box in (b) corresponds to ( FIG. 12 b ) and the larger box to ( FIG. 12 c ). The larger box in (c) corresponds to ( FIG. 12 d ) while the smaller box in (c) represents ( FIG. 12 e ). Finally, (d-f) correspond to ( FIG. 12 f - h ) respectively.
FIG. 14 depicts co-localization of GFP positive cells with GAD67. Immunohistochemical detection of GFP (a,d,g,j) and GAD67 (b,e,h,k) expression within select regions of mouse brain 21-days following postnatal day-1 injection of 4×10 11 particles of scAAV9-CB-GFP. Merged images (c,f,i,l) show limited co-localization of GFP and GAD67 signals in the cingulate gyrus (a-c), the dentate gyrus (d-f) and the hippocampus (g-i), but numerous GFP/GAD67 Purkinje cells within the cerebellum (l). Scale bars, 100 μm (c), 50 μm (a-b,d-l).
FIG. 15 depicts gel electrophoresis and silver staining of various AAV9-CBGFP vector preparations demonstrates high purity of research grade virus utilized in studies. Shown are 2 vector batches at varying concentrations demonstrating the predominant 3 viral proteins (VP); VP1, 2, 3 as the significant components of the preparation. 1 μl, 5 μl, and 10 μl were loaded of each respective batch of virus.
FIG. 16 depicts direct injection of scAAV9-CB-GFP into the brain and demonstrates predominant neuronal transduction. Injection of virus into the striatum (a) and hippocampus (b) resulted in the familiar neuronal transduction pattern as expected. Co-labeling for GFP and GFAP demonstrate a lack of astrocyte transduction in the injected structures with significant neuronal cell transduction. Scale bars, 50 μm (a), 200 μm (b).
FIG. 17 is a schematic of scAAV9/MECP2 vector.
FIG. 18 shows that systemic injection of MECP2B null/y mice with scAAV9/MECP2 virus results in MECP2 expression in different cell types in brain. (a) Experimental paradigm. (b) MECP2 expression is expressed preferentially in brainstem of injected mice (n=3). (c) Expression of MECP2 in neurons and non neuronal cells varies with brain region (n=3). In panels b and c *P<0.05, **P<0.01 and ***P<0.001 by one way ANOVA (Newman-Keuls multiple comparison test). Data are means±s.e.m.
FIG. 19 shows MECP2 expressed from virus binds to DNA, restores normal neuronal somal size and improves survival. (f) Kaplan-Meier survival curve. (g) Observational scores. MECP2Bnull/y-scAAV9/MECP2 (n=5), MECP2Bnull/y-AAV9/Control (n=6), MECP2+/y (n=6). Data are means±s.e.m. (h) Field pixel intensities of MECP2-Cy3 immunofluorescence measured from brainstem sections of non-injected and scAAV9/MECP2-injected males (left) and females (right). n=10 fields each condition. ALU, Arbitrary Linear Unit.
FIG. 20 shows systemic delivery of scAAV9/MECP2 virus into Mecp2 Bnull/+ mice prevents progression, or reverses aberrant behaviors. (a) Experimental paradigm. Mice were analyzed five months post injection. (b) Average observational scores of Mecp2 Bnull/+ mice injected with scAAV9/MeCP2 (n=8), scAAV9/Control (n=5). Non-injected (Mecp2 +/+ ) mice (n=8). Arrow indicates time of behavioral analysis. (c) Rotorod activity on third day of test. (d) Inverted grid test. (e) Platform test. scAAV9/MeCP2 (n=8), scAAV9/Control (n=5). Mecp2 +/+ (n=8). (f) Nesting ability. scAAV9/MeCP2 (n=8), scAAV9/Control (n=5). Mecp2 +/+ (n=8). *P<0.05, **P<0.01, ***P<0.001 and ns=not significant by one way ANOVA (Newman-Keuls multiple comparison test for panel c and one way ANOVA (Dunn's multiple comparison test for panels d-f. Data are means±s.e.m.
FIG. 21 is a Kaplan-Meier survival curve showing that Mecp2 Bnull/+ mice injected with scAAV9/MECP2 do not die prematurely compared to non-injected Mecp2 +/+ mice. P>0.05 by Gehan-Breslow-Wilcoxon test.
FIG. 22 shows the sequence of the genome of the exemplary rAAV9 named “scAAV9 MECP2” (SEQ ID NO: 13). Its genome has in sequence an AAV2 ITR missing the terminal resolution site (nucleotides 662-767), an approximately 730 bp murine MECP2 promoter fragment (nucleotides 859-1597), SV40 late 19s and late 16s intron sequences (1602-1661), murine MECP2 coding sequences (nucleotides 1799-3304), a bovine growth hormone polyadenylation signal sequence (nucleotides 3388-3534) and an AAV2 ITR (nucleotides 3614-3754). The scAAV9 MECP2 genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome.
FIG. 23 shows the sequence of the genome of the exemplary rAAV9 named “scAAV9 hMECP2” (SEQ ID NO: 14) Its genome has in sequence an AAV2 ITR missing the terminal resolution site (nucleotides 662-767), an approximately 730 bp murine MECP2 promoter fragment (nucleotides 859-1597), SV40 late 19s and late 16s intron sequences (nucleotides 1602-1661), human MECP2α coding sequences (nucleotides 1765-3261), a bovine growth hormone polyadenylation signal sequence (nucleotides 3314-3460) and an AAV2 ITR (nucleotides 3540-3680). The scAAV9 hMECP2 genome lacks AAV rep and cap DNA, that is, there is no AAV rep or cap DNA between the ITRs of the genome.
DETAILED DESCRIPTION
The present invention is illustrated by the following examples relating to a novel rAAV9 and its ability to efficiently deliver genes to the spinal cord via intravenous delivery in both neonatal animals and in adult mice. Example 1 describes experiments showing that rAAV9 can transduce and express protein in mouse skeletal muscle. Example 2 describes experiments in which the expression of the rAAV9 transgene was examined. Example 3 describes the ability of rAAV9 to transduce and express protein in lumbar motor neurons (LMNs). Example 4 describes the evaluation of vectors that do not require second-strand synthesis. Example 5 describes experiments focused on examining whether rAAV9 vectors were enhanced for retrograde transport to target dorsal root ganglion (DRG) and LMNs or could easily pass the blood-brain-barrier (BBB) in neonates. Example 6 describes the evaluation of optimal delivery of rAAV9 expressing SMN for postnatal gene replacement in a mouse model of Type 2 SMA for function and survival. Example 7 describes the examination of the brains of mice following postnatal day-one intravenous injection of scAAV9-CBGFP. Example 8 describes the investigation of whether astrocyte transduction is related to vector purity or delivery route. Example 9 describes administration of scAAV9-GFP in a nonhuman primate. Example 10 describes experiments demonstrating that self complementary rAAV9 bearing MECP2 cDNA under control of a fragment of its own promoter (scAAV9/MECP2), was capable of significantly stabilizing or reversing disease phenotypes when administered systemically into female RTT mouse models.
Example 1
The ability of AAV9 to target and express protein in skeletal muscle was evaluated in an in vivo model system.
Intravenous administration of 1×10 11 particles of scAAV9-GFP was performed in a total volume of 50 μl to postnatal day 1 mice and the extent of muscle transduction was evaluated. The rAAV GFP genome included in sequence an AAV2 ITR, the chicken β-actin promoter with a cytomegalovirus enhancer, an SV40 intron, the GFP DNA, a polyadenylation signal sequence from bovine growth hormone and another AAV2 ITR. The ability of the AAV9 vectors to transduce skeletal muscle was evaluated using a GFP expressing vector. AAV9-GFP expressed at high levels in the skeletal muscles that were analyzed. Ten days following injections, animals were euthanized and gastrocnemius muscles were rapidly isolated, frozen using liquid nitrogen chilled isopentane, and sectioned on a cryostat at 15 μm. Analysis of muscle sections using a Zeiss Axiovert microscope equipped with GFP fluorescence demonstrated that AAV9-GFP expressed at very high levels, with over 90% of the analyzed gastrocnemius muscle transduced ( FIG. 1 ). No GFP expression was detected in PBS control treated animals ( FIG. 1 ). These results showed that AAV9 was effective at targeting and expressing in skeletal muscles.
Example 2
Transgene expression following intravenous injection in neonatal animals prior to the closure of the BBB and in adult animals was examined.
Mice used were C57Bl/6 littermates. The mother (singly housed) of each litter to be injected was removed from the cage. The postnatal day 1 (P1) pups were rested on a bed of ice for anesthetization. For neonate injections, a light microscope was used to visualize the temporal vein (located just anterior to the ear). Vector solution was drawn into a 3/10 cc 30 gauge insulin syringe. The needle was inserted into the vein and the plunger was manually depressed. Injections were in a total volume of 100 μl of a phosphate buffered saline (PBS) and virus solution. A total of 1×10 11 DNase resistant particles of scAAV9 CB GFP (Virapur LLC, San Diego) were injected. One-day-old wild-type mice received temporal vein injections of 1×10 11 particles of a self-complementary (sc) AAV9 vector [McCarty et al., Gene therapy, 10: 2112-2118 (2003)] that expressed green fluorescent protein (GFP) under control of the chicken-β-actin hybrid promoter (CB). A correct injection was verified by noting blanching of the vein. After the injection pups were returned to their cage. When the entire litter was injected, the pups were rubbed with bedding to prevent rejection by the mother. The mother was then reintroduced to the cage. Neonate animals were sacrificed ten days post injection, spinal cords and brains were extracted, rinsed in PBS, then immersion fixed in a 4% paraformaldehyde solution.
Adult tail vein injections were performed on ˜70 day old C57Bl/6 mice. Mice were placed in restraint that positioned the mouse tail in a lighted, heated groove. The tail was swabbed with alcohol then injected intravenously with a 100 μl viral solution containing a mixture of PBS and 5×10 11 DNase resistant particles of scAAV9 CB GFP. After the injection, animals were returned to their cages. Two weeks post injection, animals were anesthetized then transcardially perfused first with 0.9% saline then 4% paraformaldehyde. Brains and spinal cords were harvested and immersion fixed in 4% paraformaldehyde for an additional 24-48 hours.
Neonate and adult brains were transferred from paraformaldehyde to a 30% sucrose solution for cryoprotection. The brains were mounted onto a sliding microtome with Tissue-Tek O.C.T. compound (Sakura Finetek USA, Torrance, Calif.) and frozen with dry ice. Forty micron thick sections were divided into 5 series for histological analysis. Tissues for immediate processing were placed in 0.01 M PBS in vials. Those for storage were placed in antifreeze solution and transferred to −20° C. Spinal cords were cut into blocks of tissue 5-6 mm in length, then cut into 40 micron thick transverse sections on a vibratome. Serial sections were kept in a 96 well plate that contained 4% paraformaldehyde and were stored at 4° C.
Brains and spinal cords were both stained as floating sections. Brains were stained in a 12-well dish, and spinal cords sections were stained in a 96-well plate to maintain their rostral-caudal sequence. Tissues were washed three times for 5 minutes each in PBS, then blocked in a solution containing 10% donkey serum and 1% Triton X-100 for two hours at room temperature. After blocking, antibodies were diluted in the blocking solution at 1:500. The primary antibodies used were as follows: goat anti-ChAT and mouse anti-NeuN (Chemicon), rabbit anti-GFP (Invitrogen) and guinea pig anti-GFAP (Advanced Immunochemical). Tissues were incubated in primary antibody at 4° C. for 48-72 hours then washed three times with PBS. After washing, tissues were incubated for 2 hours at room temperature in the appropriate secondary antibodies (1:125 Jackson Immunoresearch) with DAPI. Tissues were then washed three times with PBS, mounted onto slides then coverslipped. All images were captured on a Zeiss laser-scanning confocal microscope.
Spinal cords had remarkable GFP expression throughout all levels with robust GFP expression in fibers that ascended in the dorsal columns and fibers that innervated the spinal gray matter, indicating dorsal root ganglia (DRG) transduction. GFP positive cells were also found in the ventral region of the spinal cord where lower motor neurons reside ( FIG. 2A-B ). Labeling of choline acetyl transferase (ChAT) positive cells with GFP demonstrated a large number of ChAT positive cells expressing GFP throughout all cervical and lumbar sections examined, indicating widespread LMN transduction ( FIG. 2C ). Approximately 56% of ChAT positive cells strongly expressed GFP in sections analyzed of the lumbar spinal cord (598 GFP+/1058 ChAT+, n=4) (Table 1, below). This is the highest proportion of LMNs transduced by a single injection of AAV reported. Stereology for total number of neurons in a given area and total number of GFP+ cells was performed on a Nikon E800 fluorescent microscope with computer-assisted microscopy and image analysis using StereoInvestigator software (MicroBrightField, Inc., Williston, Vt.) with the optical dissector principle to avoid oversampling errors and the Cavalieri estimation for volumetric measurements. Coronal 40 μm sections, 240 μm apart covering the regions of interest in its rostro-caudal extension was evaluated. The entire dentate gyrus, caudal retrosplenial/cingulate cortex; containing the most caudal extent of the dentate gyrus; extending medially to the subiculum and laterally to the occipital cortex, and the purkinje cell layer was sampled using ˜15-25 optical dissectors in each case. Fluorescent microscopy using a 60× objective for NeuN and GFP were utilized and cells within the optical dissector were counted on a computer screen. Neuronal density and positive GFP density were calculated by multiplying the total volume to estimate the percent of neuronal transduction in each given area as previously described [Kempermann et al., Proceedings of the National Academy of Sciences of the United States of America 94: 10409-10414 (1997)].
For motor neuron quantification, serial 40 μm thick lumbar spinal cord sections, each separated by 480 μm, were labeled as described for GFP and ChAT expression. Stained sections were serially mounted on slides from rostral to caudal, then coverslipped. Sections were evaluated using confocal microscopy (Zeiss) with a 40× objective and simultaneous FITC and Cy3 filters. FITC was visualized through a 505-530 nm band pass filter to avoid contaminating the Cy3 channel. The total number of ChAT positive cells found in the ventral horns with defined soma was tallied by careful examination through the entire z-extent of the section. GFP labeled cells were quantified in the same manner, while checking for co-localization with ChAT. The total number of cells counted per animal ranged from approximately 150-366 cells per animal. For astrocyte quantification, as with motor neurons, serial sections were stained for GFP, GFAP and EAAT2, then mounted. Using confocal microscopy with a 63× objective and simultaneous FITC and Cy5 filters, random fields in the ventral horns of lumbar spinal cord sections from tail vein injected animals were selected. The total numbers of GFP and GFAP positive cells were counted from a minimum of at least 24-fields per animal while focusing through the entire z extent of the section.
In addition to widespread DRG and motor neuron transduction, GFP-positive glial cells were observed throughout the spinal gray matter ( FIG. 2C ; arrow). The brains were next examined following P1 intravenous injection of AAV9-CB-GFP and revealed extensive GFP expression in all regions analyzed, including the hippocampus ( FIG. 2D ), cortex ( FIG. 2E ), striatum, thalamus, hypothalamus and choroid plexus, with predominant neuronal transduction. However, transduced astrocytes were also found in all regions of the brain examined ( FIG. 2F ).
The remarkable pattern of GFP expression observed following P1 administration suggests two independent modes of viral entry into the central nervous system (CNS). Due to the ubiquitous GFP expression throughout the brain, the virus likely crossed the developing BBB. However the GFP expression pattern in the neonate spinal cord is defined with respect to the specific DRG and LMN transduction. The DRG and the LMN have projections into the periphery which suggests retrograde transport may be the mechanism of transduction. In support of retrograde transport as the method of spinal cord neuronal transduction, there were no GFP positive interneurons observed in any section examined. Alternatively, the virus may have a LMN tropism after crossing the BBB, but this appears unlikely as ChAT positive cells still migrating from the central canal to the ventral horn were largely untransduced ( FIG. 2A-B ).
TABLE 1
Neonate
GFP (mean +/− s.e.m.)
NeuN (mean +/− s.e.m.)
% (mean +/− s.e.m.)
Brain
Retrosplenial/Cingulate
142,658.30 +/− 11124.71
762,104.30 +/− 38397.81
18.84 +/− 1.93
Dentate Gyrus
42,304.33 +/− 15613.33
278,043.70 +/− 11383.56
14.82 +/− 4.89
Purkinje cells
52,720.33 +/− 1951.33
73,814.66 +/− 5220.80
71.88 +/− 3.65
GFP (mean +/− s.e.m.)
ChAT (mean +/− s.e.m.)
% (mean +/− s.e.m.)
Lumbar
10 days post injection
149.5 +/− 31.65
264.5 +/− 53.72
56.18 +/− 1.95
spinal cord
21 days post injection
83.33 +/− 16.33
140.0 +/− 31.76
60.79 +/− 2.96
Adult
GFP (mean +/− s.e.m.)
GFAP (mean +/− s.e.m.)
% (mean +/− s.e.m.)
Lumbar
% GFP colabeled w/GFAP
48.00 +/− 10.12
43.00 +/− 7.00
91.44 +/− 4.82
spinal cord
% GFAP+ transduced
41.33 +/− 5.55
64.33 +/− 8.67
64.23 +/− 0.96
(grey matter)
Additional experiments were done on one-day-old wild-type mice where they were administered temporal vein injections of 4×10 11 particles of a self-complementary (sc) AAV9 vector [McCarty et al., Gene therapy 10: 2112-2118 (2003)] that expressed green fluorescent protein (GFP) under control of the chicken-β-actin hybrid promoter (CB).
Histological processing was performed as above. Brains and spinal cords were both stained as floating sections. Brains were stained in a 12-well dish, and spinal cords sections were stained in a 96-well plate to maintain their rostral-caudal sequence. Tissues were washed three-times for 5-minutes each in PBS, then blocked in a solution containing 10% donkey serum and 1% Triton X-100 for two hours at room temperature. After blocking, antibodies were diluted in the blocking solution at 1:500. The primary antibodies used were as follows: goat anti-ChAT and mouse anti-NeuN (Millipore, Billerica, Mass.), rabbit anti-GFP (Invitrogen, Carlsbad, Calif.), guinea pig anti-GFAP (Advanced Immunochemical, Long Beach, Calif.) and goat anti-GAD67 (Millipore, Billerica, Mass.). Tissues were incubated in primary antibody at 4° C. for 48-72 hours then washed three times with PBS. After washing, tissues were incubated for 2 hours at room temperature in the appropriate secondary antibodies (1:125 Jackson Immunoresearch, Westgrove, Pa.) with DAPI. Tissues were then washed three times with PBS, mounted onto slides then coverslipped. All images were captured on a Zeiss-laser-scanning confocal microscope.
Animals were sacrificed 10- or 21-days post-injection, and brains and spinal cords were evaluated for transgene expression. Robust GFP-expression was found in heart and skeletal muscles as expected. Strikingly, spinal cords had remarkable GFP-expression throughout all levels, with robust GFP-expression in fibers that ascended in the dorsal columns and fibers that innervated the spinal grey matter, indicating dorsal root ganglia (DRG) transduction. GFP-positive cells were also found in the ventral region of the spinal cord where lower motor neurons reside ( FIGS. 3 a and e ). Co-labeling for choline acetyl transferase (ChAT) and GFP-expression within the spinal cord demonstrated a large number of ChAT positive cells expressing GFP throughout all cervical and lumbar sections examined, indicating widespread LMN transduction ( FIG. 4 ). Approximately 56% of ChAT positive cells strongly expressed GFP in sections analyzed of the lumbar spinal cord of 10 day-old animals and ˜61% of 21 day-old animals, demonstrating early and persistent transgene expression in lower motor neurons (Table 1). Similar numbers of LMN expression were seen in cervical and thoracic regions of the spinal cord. This is the highest proportion of LMNs transduced by a single injection of AAV reported. In addition to widespread DRG and motor neuron transduction, we observed GFP-positive glial cells throughout the spinal grey matter, indicating that AAV9 could express in astrocytes with the CB promoter. The remarkable pattern of GFP-expression observed following postnatal day-one administration suggests two independent modes of viral entry into the CNS. Due to the ubiquitous GFP-expression throughout the brain, the virus likely crossed the developing BBB. However the GFP-expression pattern in the neonate spinal cord is defined with respect to the specific DRG and LMN transduction. The DRG and the LMN have projections into the periphery which suggests retrograde transport may be the mechanism of transduction. In support of retrograde transport as the method of spinal cord neuronal transduction, there were no GFP-positive interneurons observed in any section examined. Alternatively, the virus may have a LMN tropism after crossing the BBB, but this appears unlikely as ChAT positive cells still migrating from the central canal to the ventral horn were largely untransduced.
In situ hybridization confirmed that viral transcription, and not protein uptake, was responsible for the previously unseen transduction pattern ( FIG. 5 ).
Example 3
The ability of AAV9 to transduce and express protein in LMN was evaluated.
LMN transduction in the lumbar ventral horn was evaluated following intravenous administration of 1×10 11 particles of ss or scAAV9 GFP to postnatal day 1 mice in an effort to effectively deliver a transgene to spinal cord motor neurons. Both single-stranded and self-complementary AAV9-GFP vectors were produced via transient transfection production methods and were purified two times on CsCl gradients. The AAV9 GFP genomes are identical with the exception that scAAV genomes have a mutation in one ITR to direct packaging of specifically self-complementary virus. The single stranded AAV constructs do not contain the ITR mutation and therefore package predominantly single stranded virus. Viral preps were titered simultaneously using TAQMAN Quantitative PCR. P1 mice (n=5/group) were placed on an ice-cold plates to anesthetize and virus was delivered using 0.3 cc insulin syringes with 31 gauge needles that were inserted into the superficial facial vein. Virus was delivered in a volume of 50 μl. Animals recovered quickly after gene delivery with no adverse events noted. Animals were injected with a xylazine/ketamine mixture and were decapitated 10-days following injection and spinal cords were harvested then post-fixed in 4% paraformaldehyde, sectioned using a Vibratome and immunohistochemistry was performed using co-labeling for ChAT and GFP. Analysis of GFP expression was performed using a Zeiss Confocal Microscope.
Intravenous injection of single stranded AAV9-GFP resulted in widespread DRG transduction as evidenced by GFP positive fibers innervating the spinal grey matter and ascending in the dorsal columns ( FIG. 6A-C ). Numerous sections showed strong GFP staining in motor neurons as assessed by co-labeling GFP with Choline acetyltransferase (ChAT) ( FIG. 3E-F ). Counting the total number of motor neurons in treated animals demonstrated approximately 8% of total motor neurons residing in the lumbar region of the spinal cord were transduced. This finding was remarkable given that motor neuron transduction has typically been very low (less than 1% of total motor neurons), particularly by remote delivery approaches such as retrograde transport.
Example 4
Self-complementary scAAV9 vectors that do not require second-strand synthesis (a rate limiting step of AAV vectors) which would allow for greater efficiencies of expression in motor neurons, were evaluated.
Viral particles were prepared as in Example 3. Intravenous injections into the facial vein of P1 pups were performed as described above and the animals as described above 10 days post-injection. As with ssAAV9 injections significant transduction of DRG was observed throughout the spinal cord. Remarkably, significant motor neuron transduction in treated animals was found in the two areas of the spinal cord that were evaluated including the cervical and lumbar spinal cord. Quantification of GFP+/ChAT+ double labeled cells expressed as a percentage of total ChAT+ cells within the lumbar spinal cord showed that ˜45% of LMN were transduced by dsAAV9 compared with ˜8% of ssAAV9 ( FIG. 7E ). Indeed, some regions of the spinal cord showed >90% motor neuron transduction ( FIG. 7D ) and other regions may have greater amounts of GFP positive motor neurons, given that dim GFP positive cells were not counted due to a conservative GFP positive scoring used in the counting. This amount of LMN transduction following a single injection of AAV has not previously been reported.
Example 5
Further investigation focused on whether AAV9 vectors were enhanced for retrograde transport to target DRG and LMNs or could easily pass the BBB in neonates.
The pattern of transduction was examined to determine if it was consistent between neonates and adult animals. Adult mice were injected via tail vein delivery using 4×10 11 to 5×10 11 particles of scAAV9-CB-GFP. A strikingly different transduction pattern was seen in adult treated animals compared to the treated neonates. Most noticeably, there was an absence of GFP positive DRG fibers and a marked decrease in LMN transduction in all cervical and lumbar spinal cord sections examined. GFP-positive astrocytes were easily observed throughout the entire dorsal-ventral extent of the grey matter in all regions of the spinal cord ( FIG. 8 a - b and FIGS. 9 a - c and e - g ) with the greatest GFP-expression levels found in the higher dosed animals. Co-labeling of GFP-positive cells with astroglial markers excitatory amino acid transporter 2 (EAAT2) and glial fibrillary acidic protein (GFAP) ( FIG. 8C ) demonstrated that approximately 90% of the GFP-positive cells were astrocytes. Counts of total astrocytes in the lumbar region of the spinal cord by z-series collected confocal microscopy showed over 64% of total astrocytes were positive for GFP ( FIG. 9 i - k and Table 1). FIG. 10 depicts diagrams of coronal sections throughout the mouse brain corresponding to the approximate locations shown in ( FIG. 9 m - o ). The box in (a) corresponds to the location shown in ( FIG. 9 m ). The smaller box in (b) corresponds to ( FIG. 9 n ) and the larger box to ( FIG. 9 o ).
Viral transcription was again confirmed in adult tissues with in situ hybridization ( FIG. 5 ). Furthermore, whereas neonate intravenous injection resulted in indiscriminate astrocyte and neuronal transduction throughout the brain, adult tail-vein injections produced isolated and localized neuronal expression only in the hippocampus and dentate gyrus ( FIG. 9 m - n and FIG. 11 e - f ) in both low and high dose animals. Low-dose animals had isolated patches of transduced astrocytes scattered throughout the entire brain. Of significance, high-dose animals had extensive astrocyte and vascular transduction throughout the entire brain ( FIG. 9 m - o and FIG. 11 e - f ) that persisted for at least seven-weeks post-injection (n=5), suggesting a dose-response of transduction, without regional specificity.
To date, efficient glial transduction has not been reported for any AAV serotype indicating that AAV9 has a unique transduction property in the CNS following intravenous delivery. An occasional neuron transduced in the spinal cord, although these events were scarce in adult animals. Furthermore, whereas neonate intravenous injection resulted in indiscriminate transduction throughout the brain, adult tail vein injections produced isolated and localized neuronal expression in the hippocampus with isolated patches of glial transduction scattered throughout the entire brain. The scarcity of LMN and DRG transduction seen in the adult paradigm suggests there is a developmental period in which access by circulating virus to these cell populations becomes restricted. Assuming a dependence on retrograde transport for DRG and LMN transduction following intravenous injection, Schwann cell or synapse maturation may be an important determinant of successful rAAV9 LMN and DRG transduction.
The results demonstrate the striking capacity of AAV9 to efficiently target neurons, and in particular motor neurons in the neonate and astrocytes in the adult following intravenous delivery. A simple intravenous injection of AAV9 as described here is clinically relevant for both SMA and ALS. In the context of SMA, data suggests that increased expression of survival motor neuron (SMN) gene in LMNs may hold therapeutic benefit [Azzouz et al., The Journal of Clinical Investigation, 114: 1726-1731 (2004) and Baughan et al., Mol. Ther. 14: 54-62 (2006)]. The importance of the results presented here is that with a single injection SMN expression levels are effectively restored in LMN. Additionally, given the robust neuronal populations transduced throughout the CNS in neonatal animals, this approach also allows for overexpressing or inhibiting genes using siRNA [see, for example, Siegel et al., PLoS Biology, 2: e419 (2004)]. The results also demonstrated efficient targeting of astrocytes in adult-treated animals and this finding is relevant for treating ALS where the non-cell autonomous nature of disease progression has recently been discovered and astrocytes have been specifically linked to disease progression [Yamanaka et al., Nature Neuroscience, 11: 251-253 (2008)]. Targeting these cells with trophic factors or to circumvent aberrant glial activity is useful in treating ALS [Dodge et al., Mol. Ther., 16(6):1056-64 (2008)].
Example 6
Optimal delivery of AAV9 expressing SMN is described for postnatal gene replacement in a mouse model of Type 2 SMA.
Studies of the SMA patient population and the various SMA animal models have established a positive correlation between amounts of full-length SMN protein produced and lessened disease severity. Histone deacetylase (HDAC) inhibitors and small molecules are currently being investigated for their ability to increase transcript production or alter exon 7 inclusion from the remaining SMN2 gene [Avila et al., J. Clin. Invest., 117(3):659-71 (2007) and Chang et al., Proc. Natl. Acad. Sci. USA, 98(17):9808-9813 (2001)]. Data presented herein demonstrates that a large percentage of LMNs can be targeted with a scAAV9 vector, and SMN gene replacement to treat SMA animals is therefore contemplated.
Mendelian inheritance predicts 25% of the pups in the litters of SMA breeders to be affected. Affected SMA mice are produced by interbreeding SMN2 +/+ , SMNΔ7 +/+ , Smn +/− mice. Breeders are maintained as homozygotes for both transgenes and heterzygotes for the knockout allele. Mice were genotyped by PCR following extraction of total genomic DNA from a tail snip (see below). One primer set was used to confirm the presence of the knockout allele while the second primer set detected an intact mouse Smn allele. Animals were treated with either scAAV9 SMN or scAAV9 GFP as controls.
SMA parent mice (Smn +/− , SMN2 +/+ , SMNΔ7 +/+ ) were time mated [Monani et al., Human Molecular Genetics 9: 333-339 (2000)]. Cages were monitored 18-21 days after visualization of a vaginal plug for the presence of litters. Once litters were delivered, the mother was separated out, pups were given tattoos for identification and tail samples were collected. Tail samples were incubated in lysis solution (25 mM NaOH, 0.2 mM EDTA) at 90° C. for one hour. After incubation, tubes were placed on ice for ten minutes and then received an equal volume of neutralization solution (40 mM Tris pH5). After the neutralization buffer, the extracted genomic DNA was added to two different PCR reactions for the mouse Smn allele (Forward 1: 5′-TCCAGCTCCGGGATATTGGGATTG (SEQ ID NO: 2), Reverse 1: 5′-AGGTCCCACCACCTAAGAAAGCC (SEQ ID NO: 3), Forward 2: 5′-GTGTCTGGGCTGTAGGCATTGC (SEQ ID NO: 4), Reverse 2: 5′-GCTGTGCCTTTTGGCTTATCTG (SEQ ID NO: 5)) and one reaction for the mouse Smn knockout allele (Forward: 5′-GCCTGCGATGTCGGTTTCTGTGAGG (SEQ ID NO: 6), Reverse: 5′-CCAGCGCGGATCGGTCAGACG (SEQ ID NO: 7)). After analysis of the genotyping PCR, litters were culled to three animals. Affected animals (Smn −/− , SMN2 +/+ , SMNΔ7 +/+ ) were injected as previously described with 5×10 11 particles of self complementary AAV9 SMN or GFP [Foust et al., Nat Biotechnol 27: 59-65 (2009)].
AAV9 was produced by transient transfection procedures using a double stranded AAV2-ITR based CB-GFP vector, with a plasmid encoding Rep2Cap9 sequence as previously described [Gao et al., Journal of Virology 78: 6381-6388 (2004)] along with an adenoviral helper plasmid; pHelper (Stratagene, La Jolla, Calif.) in 293 cells. The serotype 9 sequence was verified by sequencing and was identical to that previously described [Gao et al., Journal of Virology 78: 6381-6388 (2004)]. Virus was purified by two cesium chloride density gradient purification steps, dialyzed against phosphate-buffered-saline (PBS) and formulated with 0.001% Pluronic-F68 to prevent virus aggregation and stored at 4° C. All vector preparations were titered by quantitative-PCR using Taq-Man technology. Purity of vectors was assessed by 4-12% SDS-Acrylamide gel electrophoresis and silver staining (Invitrogen, Carlsbad, Calif.).
To determine transduction levels in SMA mice (SMN2 +/+ ; SMNΔ7 +/+ ; Smn −/− ), 5×10 11 genomes of scAAV9-GFP or -SMN (n=4 per group) under control of the chicken-β-actin hybrid promoter were injected into the facial vein at P1. Forty-two ±2% of lumbar spinal motoneurons were found to express GFP 10 days post injection. The levels of SMN in the brain, spinal cord and muscle in scAAV9-SMN-treated animals are shown in. SMN levels were increased in brain, spinal cord and muscle in treated animals, but were still below controls (SMN2 +/+ ; SMNΔ7 +/+ ; Smn +/− ) in neural tissue. Spinal cord immunohistochemistry demonstrated expression of SMN within choline acetyl transferase (ChAT) positive cells after scAAV9-SMN injection.
Pups were weighed daily and tested for righting reflex every other day from P5-P13. Righting reflex is analyzed by placing animals on a flat surface on their sides and timing 30 seconds to evaluate if the animals return to a upright position [Butchbach et al., Neurobiology of Disease 27: 207-219 (2007)]. Every five days between P15 and P30, animals were tested in an open field analysis (San Diego Instruments, San Diego, Calif.). Animals were given several minutes within the testing chamber prior to the beginning of testing then activity was monitored for five minutes. Beam breaks were recorded in the X, Y and Z planes, averaged across groups at each time point and then graphed.
Whether scAAV9-SMN treatment of SMA animals improved motor function was then evaluated. SMA animals treated with scAAV9-SMN or -GFP were evaluated for the ability of the animals to right themselves compared to control and untreated animals (n=10 per group). Control animals were found to right themselves quickly, whereas the SMN- and GFP-treated SMA animals showed difficulty at P5. By P13, however, 90% of SMN treated animals could right themselves compared to 20% of GFP-treated controls and 0% of untreated SMA animals, demonstrating that SMN-treated animals improved. Evaluating animals at P18 showed SMN-treated animals were larger than GFP-treated but smaller than controls. Locomotive ability of the SMN-treated animals were nearly identical to controls as assayed by x, y and z plane beam breaks (open field testing) and wheel running. Age-matched untreated SMA animals were not available as controls for open field or running wheel analysis due to their short lifespan.
Survival in SMN-treated SMA animals (n=11) compared to GFP-treated SMA animals (n=11) was then evaluated using Kaplan Meier survival analysis. No GFP-treated control animals survived past P22, with a median lifespan of 15.5 days. The body weight in treated SMN- or GFP-treated animals compared to wild-type littermates was analyzed. The GFP-treated animal's weight peaked at P10 and then precipitously declined until death. In contrast, SMN-treated animals showed a steady weight gain to approximately P40, where the weight stabilized at 17 grams, half of the weight of controls. No deaths occurred in the SMN-treated group until P97. Furthermore, this death appeared to be unrelated to SMA. The mouse died after trimming of long extensor teeth. Four animals (P90-99) were euthanized for electrophysiology of neuromuscular junctions (NMJ). The remaining six animals remain alive, surpassing 250 days of age.
For electrophysiology analysis, a recording chamber was continuously perfused with Ringer's solution containing the following (in mmol/l): 118 NaCl, 3.5 KCl, 2 CaCl 2 , 0.7 MgSO 4 , 26.2 NaHCO 3 , 1.7 NaH 2 PO 4 , and 5.5 glucose, pH 7.3-7.4 (20-22° C., equilibrated with 95% O 2 and 5% CO 2 ). Endplate recordings were performed as follows. After dissection, the tibialis anterior muscle was partially bisected and folded apart to flatten the muscle. After pinning, muscle strips were stained with 10 μM 4-Di-2ASP [4-(4-diethylaminostyryl)-Nmethylpyridinium iodide] (Molecular Probes) and imaged with an upright epifluorescence microscope. At this concentration, 4-Di-2ASP staining enabled visualization of surface nerve terminals as well as individual surface muscle fibers. All of the endplates were imaged and impaled within 100 μm. Two-electrode voltage clamp were used to measure endplate current (EPC) and miniature EPC (MEPC) amplitude. Muscle fibers were crushed away from the endplate band and voltage clamped to −45 mV to avoid movement after nerve stimulation.
To determine whether the reduction in endplate currents (EPCs) was corrected with scAAV9-SMN, EPCs were recorded from the tibialis anterior (TA) muscle [Wang et al., J Neurosci 24, 10687-10692 (2004)]. P9-10 animals were evaluated to ensure the presence of the reported abnormalities within our mice. Control mice had an EPC amplitude of 19.1±0.8 nA versus 6.4±0.8 nA in untreated SMA animals (p=0.001) confirming published results [Kong et al., J Neurosci 29, 842-851 (2009)]. Interestingly, P10 scAAV9-SMN-treated SMA animals had a significant improvement (8.8±0.8 vs. 6.4±0.8 nA, p<0.05) over age-matched untreated SMA animals. Gene therapy treatment, however, had not restored normal EPC at P10 (19.1±0.8 vs. 8.8±0.8 nA, p=0.001). At P90-99, there was no difference in EPC amplitude between controls and SMA mice that had been treated with scAAV-SMN. Thus, treatment with scAAV9-SMN fully corrected the reduction in synaptic current. Importantly, P90-99 age-matched untreated SMA animals were not available as controls due to their short lifespan.
The number of synaptic vesicles released following nerve stimulation (quantal content) and the amplitude of the muscle response to the transmitter released from a single vesicle (quantal amplitude) determine the amplitude of EPCs. Untreated SMA mice have a reduction in EPC due primarily to reduced quantal content [Kong et al., J Neurosci 29, 842-851 (2009)]. In our P9-10 cohort, untreated SMA animals had a reduced quantal content when compared with wild-type controls (5.7±0.6 vs. 12.8±0.6, p<0.05), but scAAV9-SMN treated animals were again improved over the untreated animals (9.5±0.6 vs. 5.7±0.6, p<0.05), but not to the level of wild-type animals (9.5±0.6 vs. 12.8±0.6, p<0.05). At P90-99, when quantal content was measured in treated SMA mice, a mild reduction was present (control=61.3±3.5, SMA-treated=50.3±2.6, p<0.05), but was compensated for by a statistically significant increase in quantal amplitude (control=1.39±0.06, SMA treated=1.74±0.08, p<0.05). Quantal amplitudes in young animals had no significant differences (control=1.6±0.1, untreated SMA=1.3±0.1, treated SMA=1.1±0.1 nA, p=0.28).
The reduction in vesicle release in untreated SMA mice was due to a decrease in probability of vesicle release, demonstrated by increased facilitation of EPCs during repetitive stimulation [Kong et al., J Neurosci 29: 842-851 (2009)]. Both control and treated SMA EPCs were reduced by close to 20% by the 10th pulse of a 50 Hz train of stimuli (22±3% reduction in control vs 19±1% reduction in treated SMA, p=0.36). This demonstrates that the reduction in probability of release was corrected by replacement of SMN. During electrophysiologic recording, no evidence of denervation was noted. Furthermore, all adult NMJs analyzed showed normal morphology and full maturity. P9-10 transverse abdominis immunohistochemistry showed the typical neurofilament accumulation in untreated SMA NMJs[Kong et al., J Neurosci 29: 842-851 (2009)], whereas treated SMA NMJs showed a marked reduction in neurofilament accumulation.
A recent study using an HDAC inhibitor to extend survival of SMA mice reported necrosis of the extremities and internal tissues [Narver et al., Ann Neurol 64: 465-470 (2008)]. In the studies described herein, mice developed necrotic pinna between P45-70. Pathological examination of the pinna noted vascular necrosis, but necrosis was not found elsewhere.
To explore the therapeutic window in SMA mice, systemic scAAV9-GFP injections were performed at varying postnatal time points to evaluate the pattern of transduction of motor neurons and astrocytes. scAAV9-GFP systemic injections in mice on P2, P5 or P10 showed distinct differences in the spinal cord. There was a shift from neuronal transduction in P2-treated animals toward predominantly glial transduction in older, P10 animals, consistent with previous studies and knowledge of the developing blood-brain barrier in mice [Foust et al., Nat. Biotechnol. 27: 59-65 (2009); Saunders et al., Nat. Biotechnol. 27: 804-805, author reply 805 (2009)].
To determine the therapeutic effect of SMN delivery at these various time points, small cohorts of SMA-affected mice were injected with scAAV9-SMN on P2, P5 and P10 and evaluated for changes in survival and body weight. P2-injected animals were rescued and indistinguishable from animals injected with scAAV9-SMN on P1. However, P5-injected animals showed a more modest increase in survival of approximately 15 days, whereas P10-injected animals were indistinguishable from GFP-injected SMA pups. These findings support previous studies demonstrating the importance of increasing SMN levels in neurons of SMA mice [Gavrilina et al., Hum. Mol. Genet. 17: 1063-1075 (2008)]. Furthermore, these results suggest a period during development in which intravenous injection of scAAV9 can target neurons in sufficient numbers for benefit in SMA.
The above results demonstrate robust, postnatal rescue of SMA mice with correction of motor function, neuromuscular electrophysiology, and increased survival following a one-time gene delivery of SMN. Intravenous scAAV9 treats neurons, muscle and vascular endothelium. Vascular delivery of scAAV9 SMN in the mouse was safe, and well tolerated.
Example 7
The brains of mice were examined following postnatal day-one intravenous injection of scAAV9-CBGFP and extensive GFP-expression was found in all regions analyzed, including the striatum, cortex, anterior commisure, internal capsule, corpus callosum, hippocampus and dentate gyrus, midbrain and cerebellum ( FIG. 12 a - h , respectively, FIG. 11 ). GFP-positive cells included both neurons and astrocytes throughout the brain. To further characterize the transduced neurons, brains were co-labeled for GFP and GAD67, a GABAergic marker. FIG. 13 depicts diagrams of coronal sections throughout the mouse brain corresponding to the approximate locations shown in FIG. 12 a - h for postnatal day-1 injected neonatal mouse brains. The box in ( 13 a ) corresponds to the location of ( FIG. 12 a ). The smaller box in ( 13 b ) corresponds to ( FIG. 12 b ) and the larger box to ( FIG. 12 c ). The larger box in ( 13 c ) corresponds to ( FIG. 12 d ) while the smaller box in ( 13 c ) represents ( FIG. 12 e ). Finally, ( 13 d - f ) correspond to ( FIG. 12 f - h ) respectively.
The cortex, hippocampus and dentate had very little colocalization between GFP and GAD67 labeled cells ( FIG. 14 a - i ), while Purkinje cells in the cerebellum were extensively co-labeled ( FIG. 14 j - l ). Finally, unbiased-estimated stereological quantification of transduction showed that 18.8+/−1.9% within the retrosplenial/cingulate cortex, 14.8+/−4.8% within the dentate gyrus and 71.8+/−3.65% within the Purkinje layer of total neurons were transduced following a one-time administration of virus (Table 1).
Example 8
Efficient astrocyte transduction by an AAV8-, but not an AAV9-vector, following direct brain injection has been previously reported. Astrocyte transduction, however, was suggested to be related to viral purification [Klein et al., Mol Ther 16: 89-96 (2008)]. To investigate whether AAV9 astrocyte transduction was related to vector purity or delivery route, multiple AAV9 preparations were evaluated for vector purity by silver-stain and 8×10 10 particles of the same scAAV9-CB-GFP vector preparations from the intravenous experiments were injected into the striatum and dentate gyrus of adult mice. Silver-staining showed that vector preparations were relatively pure and of research grade quality ( FIG. 15 ). Two-weeks post-intracranial injection, we observed significant neuronal transduction within the injected regions using these vector preparations. However, no evidence for colocalization was found between GFP and GFAP labeling throughout the injected brains (n=3) ( FIG. 16 ), as previously reported [Cearley et al., Mol Ther 16: 1710-1718 (2008)], suggesting the astrocyte transduction in this work may be injection route- and serotype-dependent and not due to vector purity.
The scarcity of LMN and DRG transduction seen in the adult paradigm suggests there is a developmental period in which access by circulating virus to these cell populations becomes restricted. Assuming a dependence on retrograde transport for DRG and LMN transduction following intravenous injection, Schwann cell or synapse maturation may be an important determinant of successful AAV9 LMN and DRG transduction. Direct intramuscular injection of AAV9 into adults did not result in readily detectable expression in motor neurons by retrograde transport. These results suggest that AAV9 escapes brain vasculature in a similar manner as skeletal and cardiac muscle vasculature. Once free of the vasculature, these data suggest that AAV9 infects the astrocytic-perivascular-endfeet that surround capillary endothelial cells [Abbott et al., Nat Rev Neurosci 7: 41-53 (2006)].
In summary, these results demonstrate the unique capacity of AAV9 to efficiently target cells within the CNS, and in particular widespread neuronal and motor neuron transduction in the neonate, and extensive astrocyte transduction in the adult following intravenous delivery. A simple intravenous injection of AAV9 as described herein may be clinically relevant for both SMA and ALS. In the context of SMA, data suggest that increased expression of survival motor neuron (SMN) gene in LMNs may hold therapeutic benefit [Azzouz et al., The Journal of Clinical Investigation 114: 1726-1731 (2004); Baughan et al., Mol Ther 14: 54-62 (2006)]. The importance of the results presented here is that a single injection may be able to effectively restore SMN expression levels in LMNs. Additionally, given the robust neuronal populations transduced throughout the CNS in neonatal animals, this approach may also allow for rapid, relatively inexpensive generation of chimeric animals for gene overexpression, or gene knock-down [Siegel et al., PLoS Biology 2: e419 (2004)]. Additionally, constructing AAV9 based vectors with neuronal or astrocyte specific promoters may allow further specificity, given that AAV9 targets multiple non-neuronal tissues following intravenous delivery [Inagaki et al., Mol Ther 14: 45-53 (2006); Pacak et al., Circulation Research 99: e3-9 (2006)]. The results also demonstrate efficient targeting of astrocytes in adult-treated animals, and this finding is relevant for treating ALS, where the non-cell autonomous nature of disease progression has recently been discovered, and astrocytes have been specifically linked to disease progression [Yamanaka et al., Nature Neuroscience 11: 251-253 (2008)]. The ability to target astrocytes for producing trophic factors, or to circumvent aberrant glial activity may be beneficial for treating ALS24. In sum, these data highlight a relatively non-invasive method to efficiently deliver genes to the CNS and are useful in basic and clinical neurology studies.
Example 9
The ability of scAAV9 to traverse the blood-brain barrier in nonhuman primates [Kota et al., Sci. Transl. Med 1: 6-15 (2009)] was also investigated. A male cynomolgus macaque was intravenously injected on P1 with 1×10 14 particles (2.2×10 11 particles/g of body weight) of scAAV9-GFP and euthanized it 25 days after injection. Examination of the spinal cord revealed robust GFP expression within the dorsal root ganglia and motor neurons along the entire neuraxis, as seen in P1-injected mice. This finding demonstrated that early systemic delivery of scAAV9 efficiently targets motor neurons in a nonhuman primate.
Example 10
Self complementary (sc) rAAV9 bearing MECP2 cDNA under control of a fragment of its own promoter (scAAV9/MECP2), was shown to be capable of significantly stabilizing or reversing disease phenotypes when administered systemically into female RTT mouse models.
To counteract possible over-expression and better mimic the expression pattern of virally-mediated MECP2, a rAAV9 containing MECP2 (E1) cDNA under control of an ˜730 bp fragment of its own promoter was constructed [Rastegar et al., PloS One, 4: e6810 (2009)] (scAAV9 MECP2; FIG. 17 ).
Mouse MECP2-α polynucldeotide was cloned in a plasmid downstream of a 730 bp fragment of MECP2 promoter. Recombinant AAV9 was produced by transient transfection procedures using a double-stranded AAV2-ITR-based MECP2 minimal promoter-MECP2 (E1) vector, with a plasmid encoding Rep2Cap9 sequence as previously described along with an adenoviral helper plasmid pHelper (Stratagene) in 293 cells [Gao et al., J. Virol. 78: 6381-6388 (2004) and Fu et al., Mol Ther., 8(6): 911-917 (2003)]. Virus was purified by cesium chloride density gradient purification steps as previously described, dialyzed against PBS and formulated with 0.001% Pluronic-F68 to prevent virus aggregation and stored at 4° C. [Ayuso et al., Gene Ther., 17(4):503-510 (2010)]. All vector preparations were titered by quantitative PCR using Taq-Man technology. Purity of vectors was assessed by 4-12% SDS-acrylamide gel electrophoresis and silver staining (Invitrogen). The resulting rAAV9 was named “scAAV9/MECP2.” The sequence of its genome is shown in FIG. 22 and has in sequence: a mutated AAV2 ITR lacking the terminal resolution site, an approximately 730 bp murine MECP2 promoter fragment, SV40 intron sequences, murine MECP2α cDNA, a bovine growth hormone polyadenylation signal sequence and an AAV2 ITR.
Mice were group housed with littermates in standard housing on a 12:12 h light:dark cycle. MECP2 Stop (Stock number: 006849) [Guy et al., Science, 315: 1143-1147 (2007)] and MECP2 Bird.knockout (Stock number: 003890; MECP2 Bnull ) [Guy et al., Nature Genetics, 27: 322-326 (2001)] mice were obtained from Jackson Laboratories and were on a C57BL/6 background. The wild type male mice were crossed to female MECP2 +/Stop and MECP2 +/Bnull mice to yield male and female MECP2 Stop and MECP2 Bnull genotypes. The floxed Stop sequence was identified from tail biopsies using the following primers: common 5′-AACAGTGCCAGCTGCTCTTC-3′ (SEQ ID NO: 8), WT 5′-CTGTATCCTTGGGTCAAGCTG-3′ (SEQ ID NO: 9), and mutant 5′-GCCAGAGGCCACTTGTGTAG-3′ (SEQ ID NO: 10). For Bird null following primers were used 5′-CCACCCTCCAGTTTGGTTTA-3′ (SEQ ID NO: 11) and 5′-GACCCCTTGGGACTGAAGTT-3′ (SEQ ID NO: 12) [Lioy et al., Nature, 475: 497-500 (2011)].
Mice were placed in a restraint that positioned the mouse tail in a lighted, heated groove. The tail was swabbed with alcohol then injected intravenously with a 300 μl viral solution containing 3×10 12 DNase-resistant particles of scAAV9 in PBS ( FIG. 20 , panel A). After the injection, mice were returned to their cages. All animal procedures were approved by Oregon Health and Science University Institutional Animal Care and Use Committee.
For phenotype scoring, mice were removed from their home cage and placed onto a metal laminar flow hood for observation.
For mobility: 0=wild type; 1=reduced movement when compared to wild type, with extended freezing periods or extended delay to movement when first placed on the surface; 2=complete loss of movement when placed on the surface.
For gait: 0=wild type; 1=hind limbs spread wider than wild type when ambulating and/or a lowered pelvis when ambulating; 2=lack of full strides by hind limbs resulting in a dragging of hindquarters.
For hind limb clasping: 0=WT; hind limbs splay outward when suspended by the tail; 1=one hind limb is pulled into the body or forelimbs are stiff and splayed outward without motion; 2=one hind limb is pulled into the body and forelimbs are stiff and splayed outward without motion and might form a widened bowl shape, or both hind limbs are pulled into the body with or without abnormal forelimb posture.
For tremor: 0=no tremor; 1=intermittent mild tremor; 2=continuous tremor or intermittent violent tremor.
For general condition: 0=shiny coat, clear and opened eyes, normal body stance; 1=dull or squinty eyes, dull or ungroomed coat, somewhat hunched stance; 2=piloerection, hunched stance.
For behavioral testing, all tests were performed at the same time of day (12.00 to 18.00 hrs) and in the same dedicated observation room. Mice were never subjected to multiple tasks on the same day.
Open field activity—Mice were placed singly into the center of an open field arena (14×14 inches) equipped to record live images from the top. Activity was recorded for 20 minutes using StereoScan Software (Clever Systems) on a Dell computer fitted with a window operating system. Software calculated the total distance travelled and average velocity of the movements from recorded movies. The mice could not see the experimenter during recordings.
Rotorod—Mice were placed on an elevated rotating rod (diameter: 7 cm, elevated: 45 cm, Economex, Columbus Instruments, Columbus, Ohio, USA), initially rotating at 5.0 rpm. The rod accelerated 5.0 rpm/s. The latency to fall (s) was recorded manually by using individual mouse specific stopwatches. Each mouse receives three trials per day, with no delay between trials, on three consecutive days.
Platform test—Performed as described in Grady et al., J. Neuroscience, 26: 2841-2851 (2006) with some modifications. Each mouse was timed for how long it remained on an elevated, circular platform (3.0 cm in diameter) with rounded edges. A maximum score of 60 s was assigned if the mouse remained on the platform for the entire test trial without falling. Two trials were administered for each test with 4 h intervening between trials, and means were calculated across the trials for each mouse.
Inverted screen test—Performed as described in Grady et al., 2006 with some modifications. Each mouse was placed in the middle of wire grid (parallel metal wires 0.5 cm apart) that was inverted to 180°. A mouse was timed for how long it remained upside down on the screen, with a maximum score of 60 s being given if the animal did not fall. Two trials were administered for each test with 4 h intervening between trials, and means were calculated across the trials for each mouse.
Nesting ability—Mice were placed in individual cages and provided with a nest building material (5 cm×5 cm×0.5 cm). The material was placed in top left corner of cage and nesting ability was scored over night based on the interaction of individual mouse with nesting material. The score of 0, 1, 2 and 3 were assigned. The score 0 was assigned to mouse that not at all interacted with material, score 3 was assigned to mouse that completely used the material to build a nest.
Novel Object recognition test—Test is conducted in open field arena used to evaluate motor activity. The two objects (a sphere and a box) were selected based on similar volume and unbiased interaction of wild type mice. During habituation, the mice were allowed to explore an empty arena for 5 minutes. Twenty-four hours after habituation, the mice were exposed to the familiar arena with two identical objects (sphere) placed at an equal distance for 5 minutes. The next day, same exercise was repeated. On third day of the test, the mice are allowed to explore the open field in the presence of the familiar and a novel object (Box) for 5 minutes to test cognition. The time spent exploring each object on second and final day of test was recorded to estimate the extent of novel object recognition by calculating discrimination index (DI)=(Tn−Tf)/(Tn+Tf). Tn; time with novel object and Tf; time with familiar object. The DI value can vary between +1 and −1, where a positive score indicates more time spent with the novel object, a negative score indicates more time spent with the familiar object, and a zero score indicates a null preference.
After phenotypic scoring and behavioral testing, mice were anaesthetized by intraperitoneal injection of Avertin (2-2-2 Tribromoethanol) and sacrificed by transcardial perfusion of 4% parafomaldehyde in phosphate-buffered saline. Brains were equilibrated in 30% sucrose overnight at 4° C. Sagittal sections (40 μm) were cut at −20° C. using a cryostat (Leica) and stored at −20° C. Sections were immunolabeled overnight at 4° C. using the following primary antibodies: rabbit-MECP2 (1:500, Covance), mouse-GFAP (1:500, Abcam), chicken-GFAP (1:200, Abeam), mouse-NeuN (1:200, Millipore). Appropriate Alexa/Dylight Fluor secondary antibodies (1:500, Molecular Probes) were used for 1 h at room temperature. DAPI was present in the ProLong Gold Antifade (Invitrogen) mounting reagent. Nissl staining (at either 594 nm or 640 nm) was performed as instructed by the manufacturer (NeuroTrace, Invitrogen). All images were collected on a Zeiss confocal laser scanning LSM 510 microscope.
MECP2 expressing cells were identified as described in Lioy et al. (2011) with some modifications: nuclei of astrocytes (GFAP+ at 555 nm or 640 nm; NeuN− at 555 nm or 640 nm) and neurons (NeuN+ at 555 nm or 640 nm) were first identified by DAPI staining. Cells with clearly identified nuclei were then assessed for MECP2 expression by analyzing 505 nm signal (excitation: 488 nm) in the nucleus.
The following measurements were analyzed using one-way ANOVA followed, when appropriate (P<0.05), by Newman-Keuls post-hoc test: anatomical and cell-type expression patterns of transduced MECP2, whole body and brain weights, respiratory parameters, open field activity and time on rotarod. The following measurements were analyzed using Kruskal-Wallis test followed, when appropriate (P<0.05), by Dunn's multiple comparisons test: phenotype severity scores, nesting scores, time on an inverted grid, time on a platform, and novel object recognition. Survival curves were compared using the Log-Rank method. All statistics were performed using PRISM 5.0 software.
The scAAV9/MECP2 construct is expressed in both neurons and glia in vitro, and in MECP2Bnull/y mice, virally-expressed MECP2 was detected immunochemically in heterochromatic puncta of both cell types, indicating wild type DNA binding function. Notably, MECP2-positive neurons in the CA3 region of scAAV9/MECP2-injected males had significantly larger somal sizes than MECP2-negative neurons.
The MECP2 expressed from scAAV9/MECP2 was detected throughout the brain. However, with the exception of cerebellum, MECP2 expression was not over represented in astrocytes, ( FIG. 18 ). This could reflect, in part, the specific cell specific regulatory elements in the cloned promoter fragment because MECP2 is expressed generally at lower levels in astocytes than neurons [Ballas et al., Nature Neuroscience, 12: 311-317 (2009) and Skene et al., Molecular Cell, 37: 457-468 (2010)]. Consistent with all of these metrics, the injected male mice had prolonged lifespans and improved observational scores compared to control injected mice ( FIG. 19 , panels a and b).
A potential concern with virally-mediated gene transfer of MECP2 is over-expression, because MECP2 duplication gives rise to a neurological disease [del Gaudio et al., Genetics in Medicine, 8: 784-792 (2006) and Friez et al., Pediatrics, 118: e1687-1695 (2006)]. To assess this issue, in an unbiased manner, the average MECP2 expression level was determined in transduced brains by recording field pixel intensities of MECP2-Cy3 fluorescence in hindbrain sections selected randomly. The results indicated that scAAV9/MECP2 injection resulted in physiological levels of MECP2 protein ( FIG. 19 , panel c). Interestingly, WT brains showed two peaks of MECP2 fluorescence that were precisely recapitulated in the MECP2 transduced brains, although the cellular nature of the fluorescence is not identified by this method of analysis.
Having established that scAAV9/MECP2 programmed MECP2 expression to approximately physiological levels in multiple cell types in brain, rescue parameters were examined in 10 to 12 month-old symptomatic MECP2Bnull/+ mice that were systemically injected with scAAV9/MECP2 or control virus ( FIG. 21 ). Like the males, there was no evidence for over-expression of MECP2 and viral therapy did not compromise survival ( FIG. 19 , panel c; FIG. 21 ). The observational scores increased initially from two to three. Strikingly, by 12-weeks, scAAV9/MECP2 injected females stabilized at an improved score of one until the end of scoring at 24-weeks, while females injected with control virus progressed to a score of nearly six ( FIG. 20 , panel b). The scAAV9/MECP2 injected MECP2Bnull/+ mice also performed significantly better than scAAV9/control females in rotorod, inverted grid and platform tests, and nesting ability ( FIG. 20 , panels c-f). None of the injected females exhibited seizures, unlike the females injected with control virus (2/5).
Previous gene therapy work has shown modest, but encouraging, improvement of symptoms in male mouse models of RTT [Gadalla et al., Mol. Ther., 21: 18-30 (2013)]. However, the disease initiates and progresses differently in females and males, due to the mosaic nature of MECP2 loss of function in females. Therefore, therapeutics designed especially for affected females are required. The results presented herein are important because they suggest, for the first time, that symptoms in human RTT female patients may be reversible by ectopic expression of MECP2 in a rAAV9 virus that infects peripheral tissue and multiple cell types within the CNS. Interestingly, the experiments also indicate that not every cell needs to be repaired with MECP2 in order to stabilize or reverse phenotypes in female mice, consistent with the finding that an ˜5% increase in MECP2 levels over WT levels is sufficient to mediate longer lifespans [Robinson et al., Brain, 135: 2699-2710 (2012) and Lioy et al. (2011).
While the present invention has been described in terms of various embodiments and examples, it is understood that variations and improvements will occur to those skilled in the art. Therefore, only such limitations as appear in the claims should be placed on the invention.
All documents referred to in this application, including priority documents, are hereby incorporated by reference in their entirety with particular attention to the content for which they are referred. | The present invention relates to Adeno-associated virus 9 methods and materials useful for systemically delivering polynucleotides across the blood brain barrier. Accordingly, the present invention also relates to methods and materials useful for systemically delivering polynucleotides to the central and peripheral nervous systems. The present invention also relates to Adeno-associated virus type 9 methods and materials useful for intrathecal delivery of polynucleotides. Use of the methods and materials is indicated, for example, for treatment of lower motor neuron diseases such as spinal muscle atrophy and amyotrophic lateral sclerosis as well as Pompe disease and lysosomal storage disorders. Use of the methods and materials is also indicated, for example, for treatment of Rett syndrome. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to an input device, and more particularly it relates to a membrane-type of input device for introducing electrical signals into a microcomputer-based circuit or other circuits.
To accomplish a wide range of functions in a variety of household appliances including microwave ovens, microcomputers are in increasing use. A number of key switches, variable resistors of rotary or slide type and the like are used in conjunction with those microcomputers for introduction of electrical signals thereto. In the case of microwave ovens, variable resistors are more advantageous than key switches for entering numerical representations of heating parameters such as time and temperature because the former demands merely selecting a desired resistance value while the latter requires actuation of a desired number of key switches. Even though it is advantageous in the above aspect, the variable resistor has inherent disadvantages in that the structure is complex and costly and its protruding knob is difficult to clean. The last problem is critical especially in microwave ovens which should be constantly kept clean.
OBJECT AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an electric signal input device which is capable of introducing a number of information bits selectively through a simple operation and a minimum of expenditures.
To accomplish the above mentioned object, the present invention provides an electric signal input device which comprises an actuator means composed of a generally flat plate having a plurality of elongated actuator sections on a surface thereof and carrying a plurality of first electrodes disposed wholly through an opposite surface thereof and facing against said plurality of actuator sections. A substrate is disposed in conjunction with said actuator means and has a plurality of second electrodes one corresponding to each of said first electrode. Said first and second electrodes are brought into electric contact when the corresponding one of said actuator sections is depressed and becomes bent. Means are provided for sensing where said first and second electrodes are in electric contact along the length of said actuator sections.
Therefore, the input device includes the elongated array of first electrodes disposed along the opposite surface of the actuator means also carrying the corresponding number of actuator sections and the elongated array of the second electrodes disposed on the substrate each in opposing relationship with the respective one of said first electrodes so that an electric signal descriptive of where the first and second electrodes are brought into electric contact may be derived through only one depression of the corresponding one of the actuator sections. A number of information bits may be, therefore, selectively introduced through simple operation. Further, the input device embodying the present invention is simpler in structure than the conventional variable resistor of either the rotary or slide type. The actuator means is flat, easy to clean and useful widely for home appliances where cleanliness is of importance.
BRIEF DESCRIPTION OF THE DRAWING
For a more complete understanding of the present invention and for appreciating further objects and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawing, in which:
FIG. 1 is a perspective view of a cooking appliance having a built-in electrical signal input device constructed according to an embodiment of the present invention;
FIG. 2 is an exploded perspective view of the electrical signal input device of FIG. 1;
FIG. 3 is a cross-sectional view of the electrical signal input device shown in FIG. 2;
FIG. 4 is a perspective view of the electrical signal input device as viewed from back;
FIG. 5 is a partial plan view of an electrode sheet 15;
FIG. 6 is a cross-sectional view of another embodiment of the present invention;
FIG. 7 is a cross sectional view of still another embodiment of the present invention;
FIG. 8 is a partially exploded perspective view of the electrical signal input device as illustrated in FIG. 7; and
FIG. 9 is a perspective view for explanation of the procedure by which the spacers 24 are disposed on a protective film 20.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, there is illustrated a perspective view of a cooking appliance 2 having a built-in electrical signal input device 1 constructed according to an embodiment of the present invention. The electrical signal input device 1 has an actuator region 3 for selection of either microwave or dielectric heating of food, an actuator region 4 for selection of grill heating as is necessary in simmering food and an actuator region 5 for selection of oven heating as is needed for browning food. Further, disposed respectively below those actuator region 3 to 5 are an actuator regions 6 for setting microwave heating time, an actuator region 7 for setting grill heating time and an actuator region 8 for setting oven heating temperature, all of which are designed according to the present invention. An actuator region 9 is depressed when food is to be heated and an actuator region 10 is depressed when heating is to stop. Electrical signals from the electrical signal input device 1 are introduced into a microcomputer 39 (see FIG. 2) contained in the appliance 2 for controlling the heating of food.
FIG. 2 is an exploded perspective view of the electrical signal input device 1 and FIG. 3 is a longitudinal cross-sectional view of the input device 1. The electrical signal input device 1 generally includes an actuator member 11 and a substrate 12 disposed behind the actuator member 11. The actuator member 11 is made of a flexible and elastic plate with a generally flat laminated structure which includes a cover sheet 13, a spacer 14 and an electrode sheet 15. The cover sheet 13 includes a transparent plastic film 16 carrying on its rear surface indicia 17 characteristic of the actuator region 8 as formed by printing of elastic ink or adhering. An aluminum foil 18 is adhered, printed, deposited or otherwise affixed on cover sheet 13 in such a manner as to screen the film 16 and the indicia 17.
The spacer 14 is made of electrically insulating plastic material having punched or perforated portions corresponding to the respective actuator regions 3 to 10. When a particular one of the actuator regions is not actuated, the spacer 14 keeps its associated pusher or pushers 21 out of contact with the aluminum foil 18 and holds the film 16 flat. It is understood that the actuator regions 6 to 8 extend preferably along the vertical direction of the cooking appliance 2.
The rear electrode sheet 15 includes a protective film 20 typically of electrically insulating and flexible plastic material. On a surface of the protective film 20 facing against the cover sheet 13 there are equally spaced and aligned a plurality of pushers 21 along the length of the actuator region 8. The pushers are made of plastic material having a rigidity high enough not to collapse when being depressed by the operator's finger 40. An alumimum foil 22 is adhered, deposited, printed or otherwise affixed entirely on the opposite surface of the protective film 20 adjacent the substrate 12.
FIG. 4 is a perspective view of the electrode sheet 15 as viewed from the side of the substrate 12. On the aluminum foil 22 there is a plurality of first electrodes 23 aligned at a given interval along the length of the actuator region 8, which electrodes are typically made of a electrically conductive material with low resistance such as carbon. These electrodes may be disposed thereon by painting, printing or other conventional manners. The first electrodes 23 are located beneath the respective pushers 21. Spacers 24, typically formed of an electrically insulating material such as a plastic are interposed between each two adjacent first electrodes 23 along the length of the actuator region 8. The spacers 24 extend along the width of the actuator region 8 and have a rigidity high enough not to collapse when being depressed. In conjunction with the remaining actuator regions 6 and 7, the pushers 21, the first electrodes 23 and the spacers 24 are provided in a likewise manner. To set up the actuator regions 5 and 9, pushers 25 and 26 are mounted on the protective film 20 of the electrode sheet 15 and electrodes 27 and 28 are disposed beneath the pushers 25 and 26 together with spacers 29 and 35. The architecture of the remaining actuator regions 3 and 4 are similar to that of the actuator region 5 and the architecture of the actuator region 10 is similar to that of the actuator region 9. An electrode 34 corresponds to the actuator region 10. The spacers 24 have a thickness greater than the sum of the thicknesses of the first electrodes 23 and second electrodes 31 described hereinafter so that the first and second electrodes 23 and 31 may be kept in non-contacting relationship when a particular one of the actuator regions is not being actuated.
The substrate 12 is disposed face-to-face with the actuator member 11. On a support film 30 typically of an electrically insulating plastic material there is disposed a plurality of the second electrodes 31 typically formed of a conductive material such as carbon by painting, printing or other conventional manners. The respective ones of the second electrodes 31 are aligned along the length of the actuator region 8 to correspond to the respective ones of the first electrodes 23. The second electrodes 31 are connected in a serpentine fashion by means of conductors 32 which are also formed of an electrically conductive material such as carbon and are disposed on the support film 30 by painting, printing or other conventinal manners.
FIG. 5 is a plan view of a portion of the substrate 12 carrying the second electrodes 31 and the conductors 32. The second electrodes 31 have a low resistance and the conductors 32 have a high resistance. It is preferred that the transparent film 16, the protective film 20 and the support film 30 be made by of materials having substantially the same coefficient of thermal expansion, e.g., polyester and polyvinyl chloride.
An electrode 33 is provided in connection with the electrode 27 in the actuator region 5 and an electrode 35 is provided which may come into contact with the electrode 35 in the actuator region 10. The second electrodes 31 are connected to the electrode 33 by way of a conductor 37 having a high resistance. Further, the second electrodes 31 are connected to the electrode 34 by way of a conductor 36 having a high resistance. The resistance extending between a terminal 38 leading from the second electrodes 31 and the electrodes 33 and 34 connected via the conductors 32, 36 and 37 and the aluminum foil 22 is sensed by a microcomputer 39 which governs the heating operation of the cooking appliance. If any one of sections in the actuator region 8 along its length is depressed by the finger 40, then the cover sheet 13 depresses selectively the corresponding one of the pushers 21 so that the first electrode 23 beneath the depressed one of the pushers 21 comes into contact with the second electrode 31. The resistance between the terminal 38 and the aluminum foil 22 is lower when a pair of the first and second electrodes 23 and 31 near to the terminal 38 are in contact with each other and higher when first and second electrodes remote from the terminal 38 are in contact. With such measurements of the resistance, it is possible to detect discrete resistance values as a function of the finger-actuated position along the length of the actuator region 8. It is, therefore, possible to select a heating temperature along the length of the actuator region 8 and to introduce selectively the desired temperature for the cooking appliance. Whether the electrodes 27 and 33 and the electrodes 28 and 34 are in contact is determined in a similar manner.
The spacers 24, 29 and 35 mounted on the electrode sheet 15 are islands with no closed space and spaces 41 (see FIG. 3) defined by the electrode sheet 15 and the substrate 12 are open to the atmosphere. This leads to certainty that the first electrodes 23 may be brought into electrical contact with the associated second electrodes 31.
FIG. 6 is a sectional view similar to FIG. 3 but shows another embodiment of the present invention. This alternative embodiment is analogous to the above illustrated embodiment and components similar to those in the previous embodiment are represented by the same reference numbers. Attention is invited to the provision of a pressure-sensible conductive rubber member 42 interposed between the aluminum foil 22 secured on the protective film 20 of the electrode sheet 15 and the substrate 12. The pressure-sensible conductive rubber member 42 has elasticity and the electrical property that its local resistance becomes lower when being depressed. The pressure-sensible conductive rubber member 42 may be set up by a composite including 6 parts by weight of neoprene rubber and 4 parts by weight of conductive material powders such as silver powders. Respective portions of the aluminum foil 22 immediately above the second electrodes serve as the first electrodes 23. When the actuator region 8 is depressed in part by the finger, the portion of the alumimum foil 22 directly below the finger-depressed portion depresses and deforms as the first electrode the pressure-sensible rubber member 42 and moves the deformed portion of the rubber member close to the second electrode 31 so that a path is bridged having a low value of resistance between the aluminum foil 22 and the second electrode 31. Provided that the resistance between the aluminum foil 22 and the terminal 38 (see FIG. 2) may now be measured, it is possible to sense the finger-actuated position along the length of the actuator region 8.
FIG. 7 is a cross-sectional view of still another embodiment and FIG. 8 is a partially exploded perspective view thereof. This embodiment is analogous to the previous embodiment, but is featured by that an elongated, strip-like electric conductor 43 of high resistance carbon or other similar electrically conductive material is painted, printed or otherwise disposed on the support film 30 on the substrate 12 and a predetermined number of second electrodes 44 of a low resistance are set up on the conductor 43 and equally spaced along the length of the actuator region 8. As described previously, the aluminum foil 22 is adhered on the protective film 20 of the electrode sheet 15 and a predetermined number of contactors 45 are mounted on the aluminum foil 22 in such a manner as to be directed toward the substrate 12. On the aluminum foil 22, there is further disposed a spacer 46 which keeps the second electrodes 44 away from the aluminum foil 22 and the contactors 45 away from the conductor 43 when any section of the actuator region is not being actuated. Upon actuation of any one of the sections of the actuator region 8, the second electrode 44 comes into contact with the portion of the aluminum foil 22 which serves as the first electrode 47 immediately above the second electrode 44. The resistance extending between the aluminum foil 22 and one end of the conductor 43 varies as a function of the position where electrical contact is established. The contactors 45 may also come into contact with the conductor 43 and their positions measured similarly.
Referring to FIG. 9, there is illustrated the procedure by which the spacers 24 are disposed and aligned on the aluminum foil 22 on the protective film 20. As seen in FIG. 9(1), an adhesive is applied to both surfaces of a film 50 forming the spacers 21 and strip sheets 51 and 52 are adhered thereon. When the strip sheets 51 and 52 are removed, the adhesive remains on the film 50 with which the film 50 may be adhered in the following manner. Slits 53 are defined in the strip sheet 51 and the film 30 by means of a Thomson model or the like as shown in FIG. 9(2). It is noted that the slits 53 are formed in the strip sheet 52. A sheet 54 with an adhesive applied thereon is secured on a surface of the strip sheet 51 with the aid of the adhesive on the sheet 54 as seen in FIG. 9(3). Thereafter, the sheet 54 and the strip sheet 51 are peeled off at the same time. The result is illustrated in FIG. 9(4). Provided that the film 50 is removed from the strip sheet 52, the insulator islands 24 remain on the strip sheet 52 as seen in FIG. 9(5), with the adhesive on the summits 24a thereof. While the strip sheet 52 is held upside down, the summits 24a are adhered to the aluminum foil 22 on the protective film 20 of the electrode sheet 15. FIG. 9(7) shows the situation after the strip sheet 52 has been removed, wherein the spacers 24 are equally aligned on the aluminum foil 22. The bottom surfaces 24b of the spacers 24 opposite the summit surfaces 24b are fixedly secured on the support film 30 by means of the adhesive remaining on the bottom surfaces 24b.
Although in the above-illustrated embodiments the second electrodes 31 are connected in series by means of the conductors 32, it will be obvious to those skilled in the art that electrical signals are introduced into the microcomputer 39 by way of individual lines leading to the respective ones of the second electrodes 31. The cover sheet 13 may be made of a single flexible film or the indicia may be printed or otherwise disposed on the foil for the actuator regions 3 to 10.
While only certain embodiments of the present invention have been described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as claimed. | There is disclosed an electrical signal input device suitable for use in a microwave oven or other household appliance for introducing a setting into those appliances through a simple one-touch actuation. The input device is of the membrane type which includes an actuator member composed of a generally flat plate having a plurality of elongated actuator sections on a surface thereof and carrying a plurality of first electrodes disposed wholly through an opposite surface thereof and facing against the plurality of the actuator sections, a substrate disposed in conjunction with the actuator member and having a plurality of second electrodes each corresponding to one of the first electrode. The first and second electrodes are brought into electrical contact when the corresponding one of the actuator sections is depressed and becomes bent. Discrete values of electrical resistance are sensed as a function of where the first and second electrodes are in electric contact along the length of the actuator sections. | 7 |
This is a continuation, of application Ser. No. 874,735, filed Feb. 3, 1978, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to practical, inexpensive mortars and aluminous high temperature cements and concretes which will withstand multiple freeze-thaw cycles without crazing, cracking or spalling to a much greater degree than have the prior art materials. Mortar and concrete that are exposed to the freezing and thawing cycle, particularly in areas where water stands thereon craze and crack when subjected to freezing, and spall when thawed thereafter. The crazing becomes more pronounced and deeper as the mortar or concrete is exposed to successive cycles. This is a major cause of the deterioration of the concrete highway system in the Northern part of the United States, and hundreds of millions of dollars are required for patching operations each year in the areas where the freeze-thaw cycle exists.
It is an object of the present invention, therefore, to provide new and improved mortars and concrete which are competitive in price to that currently used for pavement and/or building products such as shingles, siding and panels, and which will withstand the freeze-thaw cycle with considerably less damage than have prior art materials.
The prior art has experimented with all types of reinforcing materials in mortars and concrete for the purpose of increasing its strength and in some instances to try to reduce the crazing and cracking produced by the freeze-thaw cycle. To my knowledge, reinforcements have not appreciably reduced the crazing and cracking but some hold cracked areas in place so that the spalling thereof is less apparent. Water in the cracked areas, however, when frozen, spreads the cracking regardless of prior art reinforcements, so that conventional reinforcements have not been the answer to the freeze-thaw problem.
Glass fibers are produced commercially in two general types, one being blown fibers, and the other being pulled fibers. Blown fibers comprise random lengths of twisted interlocking fibers that are formed into mats or batts. Pulled fibers are made by simultaneously pulling from 200 to 2,000 molten streams of glass, grouping them when solidified into a strand, and coiling them around a rotating drum to produce a package. These pulled fibers must be coated with a size before coming together, otherwise they will break when they pass over the winding apparatus that guides them onto the rotating drum. The sizes used in practically all instances are water base sizes which cool the molten streams and prevent the mutual abrasion.
Both types of fibers have been available for over 30 years and pulled glass fiber strand has been used extensively as reinforcements in plastics. They have not proven successful in reinforcing mortars and cements, however, because the strand which was commercially available in the past has been deteriorated by alkali attack from the lime that exists in Portland cement. From the work that was done with glass fiber reinforcements in thermoset plastics, it was learned that strand having high strand integrity gave the highest flexural strength, tensile strength and impact strength; while those strands which were loosely united gave inferior strengths. Practically all strand which was produced for reinforcing purposes therefore has been sized with aqueous emulsions of plastics. These plastics help prevent deterioration from alkali attack if they remain around the strand. Strands of even high strand integrity, however, are attacked by Portland cement. Recently, so called alkali resistant glass strands have been developed. These strands even though they survive for a number of years in Portland cement mortar and concrete do not overcome the freeze-thaw problem.
According to principles of the present invention, it has been discovered that: if glass filaments are used which have a water dispersible binder and a surface which is devoid of organosilanes or lubricants which permanently make the surface of the filaments hydrophobic; and if such filaments are chopped and agitated to substantially completely disperse the filaments generally uniformly throughout, the mortar or concrete will have vastly improved resistance to the crazing, cracking and spalling produced by the freeze-thaw cycle. This is accomplished when more than approximately 0.01 percent by weight of the strand, based on the solids of the mortar or concrete are utilized, and little freeze-thaw improvement is gained by using more than approximately 1.0 percent by weight of the strand. It has been found that 0.2 percent or less of such strand is the generally preferred amount, and that it is very difficult to incorporate more than approximately 1 percent of such strand into thick mortars or concretes. It has been observed that mortar or concrete utilizing the filamentizable strand dries out much faster than conventional mortar or concrete, or mortar or concrete that is reinforced by nonfilamentizable strand; and in fact, the mortar and concrete of the present invention utilizing the filamentizable strand crumbles excessively if the surface is not kept wet during the setting of the materials.
It is now theorized that due to the packing of the sand and/or aggregate, there are minute void areas throughout mortar and concrete in which water remains after hydration is complete. When the filaments of the present invention are not used, these voids may remain full of water or may become full of water, which when frozen, expands and produces crazing and cracking.
Since only filaments that are wetted by water produce the improvements discovered by the present invention, it is further theorized that the individual filaments are so numerous that they run through these void areas. In addition, they are so numerous as to in some instances touch each other, or are sufficiently close to each other that water from voids runs along the surface of the filaments from one to another until it reaches the surface of the material. Mortar or concrete that sets with such filaments in place may also tend to produce smaller void areas. Furthermore, even if the fibers are deteriorated by alkali attack so that their strength is greatly decreased, the skeleton of the filament remains to remove water from the center of the material by means of the surface energy of the glass.
It has long been known that glass surfaces which are not "poisoned" cause water to spread out almost indefinitely, and that the angle of contact of water on nascent glass or "non-poisoned" glass approaches zero. Individually dispersed filaments, therefore, pass through or are sufficiently close to all voids of the material that they extract freezable water therefrom. Any free water that remains does not fill the voids so that freezing does not produce cracking or crazing. Even glass filaments which are badly deteriorated by alkali greatly reduce the cracking and crazing normally produced by the freeze-thaw cycle. Preferably, however, the filaments will be of an alkali resistant glass, so that the filaments remain sufficiently intact to add to the strength of the material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Example 1
A strand was produced by drawing 408 molten streams of AR glass to an average diameter of approximately 0.00036 inch, by coating the same with the following aqueous solution and coiling the strand into a package:
______________________________________Polyvinyl acetate containing a 7.5%sufficient minor amount of poly-vinyl alcohol groups to make itdispersibleCationic lubricant (fatty acid- 0.2%tetraethylene pentamine condensate)Glacial acetic acid 0.15%Ammonium hydroxide 0.05%Nonionic wetting agent (octyl 0.1%phenoxy polyethoxyethanol)Water Balance______________________________________
The strand after drying at 220° F. was chopped into one half inch lengths, and mortars were made according to the following formulations in parts by weight:
______________________________________Material Preferred Range______________________________________Portland cement 100 100Silica Sand 100 50-700Water 40 30-100Chopped strand 0.4 0.01-2.0______________________________________
Such mortars were cast into 11/2"×11/2"×61/2" test specimens. The test specimens were kept moist and cured at 80° F. for 28 days. Thereafter the test samples were placed in pans and fully soaked in water. The pans were then placed in a freezer at 0° F. for two hours and frozen, and were then placed in a room at 80° F. for two hours and thawed. After 100 such cycles, the test specimens were intact and had only a slight surface irregularity.
Example 2
The process of Example 1 was repeated excepting that no glass strand or filaments were used in the mortars. The test samples after 100 test cycles had completely crumbled.
Example 3
The process of Example 1 is repeated excepting that the strand is made using a non-dispersible size of the following composition:
______________________________________Materials Percent By Weight______________________________________Water soluble epoxy 1.5%Polyvinyl alcohol normal 3.85%methylolacrylamide copolymerEmulsified particles of vinyl 3.85%acetate-ethylene copolymerstabilized with acetylated poly-vinyl alcoholGammamethoxypropyltrimethoxy 0.10%silaneGlacial acetic acid 0.30%Carbowax 0.10%Lubricant 0.30%Paintable fluid, silicone emulsions 0.50%______________________________________
The test samples made from this composition when tested have far inferior freeze-thaw characteristics than did the material of Example 1.
Example 4
The process of Example 1 is repeated excepting that 1% of the 1/2 inch lengths of chopped strand is utilized. Considerable difficulty is had in mixing this amount of chopped strand into the mortar. The test samples after 100 freeze-thaw cycles are intact and have less surface irregularity than do the test specimens of Example 1.
Example 5
The process of Example 1 is repeated excepting that 0.05% of the chopped strand was utilized in making this sample. This material showed the beginning of crazing and cracking after 100 freeze-thaw cycles.
Example 6
The process of Example 1 is repeated excepting that 0.2% of AR glass filament (U.S. Pat. No. 3,840,379) sized with the sizing of Example 1 is substituted. This material has substantially the same performance characteristics as those of Example 1.
In order that filaments can be produced commercially, they must be coated at forming. The filaments to be useful in the present invention must be sized with a water dispersible material that is substantially devoid of oils, greases, silicones, and organosilanes unless they are emulsified or are dispersed by alkali so that they leave the surface of the glass upon the disruption of the size. What is more, it is preferable that the filaments be so sized in order to prevent the filaments from picking up oils and greases out of the air during their formation, storage and shipping to the point where they are chopped and are incorporated into the mortar or concrete. Suitable samples of binder materials for the sizes are starches, polyvinylacetates that are made water dispersible by the inclusion of polyvinyl alcohol in the polymer chain, etc. The mortar or concrete preferably has a cement to sand ratio of from 0.5 to 1.0. Preferably, the mortar or concrete is mixed with no more water than is necessary to make it pourable so that free water does not stand on the surface. After pouring, the surface should be prevented from drying out as by covering with plastic, or artificially wetting the same periodically, etc. The filaments preferably have a diameter of between 0.00020 and 0.00070 inches. No advantages are obtained from larger diameters since the filaments become relatively stiff and the surface area per pound is considerably less.
A preferred material is formed using both filamentizable strand and non-filamentizable strand. It appears that the glass filaments, in addition to improving resistance to the freeze-thaw cycle, improve shatter resistance and crack propagation, while the fibers of a non-filamentized strand improve flexural and compressive strengths. The filaments when added to mortar containing non-filamentizable strand, therefore, provide a strength over and above that produced by the strand alone. In general, the amount of filamentizable strand for cast slurries may comprise from 0.01 to 0.70 and the strand will comprise 0.05 to 5 percent of lengths 1/16" to approximately 1" long. For slurries that are to be filter pressed, the filamentizable strand may comprise between 0.01 to 5.0% and the strands will comprise between 0.5% and 10.0%.
Example 7
The process of Example 1 was repeated excepting that 1.0% of a non-filamentizable AR strand composed of the fibers of Example 1 sized with the size of Example 3 was also included. The strand has a chopped length of 3/4 inch. The specimens so produced have an improvement over the specimens of Example 1 in flexural strength, tensile strength and impact strength of approximately 20%.
Example 8
Spalling resistant refractory insulating cements are made from the following materials in parts by weight:
______________________________________Material Preferred Range______________________________________Clay 25 to 50Bentonite 20.0Ball 15.0Portland cement 20.0 15 to 30Siliceous filler 10 to 30Diatomaceous earth 5.0Flyash 15.0Mineral wool 25.0 10 to 30Glass strand .2 .01 to 1.0______________________________________
The glass strand that was used was similar to that of Example 1, excepting that the strand was made of E-glass. The test specimens so produced have greatly improved resistance to spalling due to the freeze-thaw cycle than do specimens of the same formulation which do not include the filamentized glass fibers. In addition, the insulating cements have better resistance to slumping, crazing, cracking, and fissuring during drying than do cements devoid of the filaments. Insulating cements usually have a density of no more than approximately 65 pounds per cubic foot.
Example 9
A spalling resistant high alumina cement mortar is prepared from the following materials in percent by weight:
______________________________________Materials Preferred Range______________________________________High alumina cement 30 10 to 50Sand 69.8 50 to 90Strand of Example 8 0.2 .05 to 1.0______________________________________
The specimens are made using a water to cement ratio of 0.35. The test specimens produced have the same improvement in resistance to spalling during the freeze-thaw cycle test as do the specimens of Example 1.
The network of filaments that is utilized in the method and materials of the present invention must be formed by substantially completely filamentized strand since strand that is not filamentized has voids between the filaments which attract and hold water. On the other hand, individual filaments retain only a very thin layer of water, perhaps several molecules thick, and this water spreads almost indefinitely along its surface since the angle of wetting on nascent glass approaches zero. Since this is necessary, the surface of the individual filaments must not be permanently poisoned by silicones, organic polymers, oils or other nonwetting materials. It is known that nascent glass fibers in water have identical negative charges which repell each other, and this phenomenon is believed utilized to disperse the individual filaments into the criss-crossing fiber network that is necessary to pass through or adjacent all interstitial voids in the mortar. The filaments used in the present invention, in an aqueous media, develop a zeta potential of mutually repelling negative charges on the individual filaments which causes them to repell each other and spread throughout ionically neutral or similarly charged organic or inorganic body building fibers or particles. In those instances where the body building fibers are positively charged, it is possible to treat the glass filaments with acid and/or counter ions such as di or tri valent positive ions, as for example aluminum sulfate, or alum, to spread the glass filaments throughout the positively charged body building fibers.
Filaments that are held together as strands do not provide the improvement in water extraction of the present invention. Strands cannot form the necessary network of the present invention since strands are too big and cumbersome to be distributed by reason of zeta potential. With strands, the charges or the filaments are largely offset by being held together by the binder. Furthermore, water is held in the voids between the filaments of the strand to mitigate against the drying effect of the present invention. As previously stated, the reduced spalling and cracking achieved by the present invention occurs by reason of water being moved from interstitial voids to the surface of the article by travel along the surface of the fiber network. This leaves the interstitial voids only partly full of water so that expansion therein can occur during freezing without cracking the article. It is essential that the filaments be jackstrawed in a three dimensional, random fashion, and that at least 50% of the water wetting filaments be present as monofilaments completely separated from the strand from which they were added to the slurry.
The following is a table of the amount of 0.00036 inch diameter filaments per cubic inch of product for various weight percentages, based on a produce density of 120 pounds per cubic foot.
______________________________________ Inches of monofilament perPercent by Weight cubic inch of product______________________________________0.01 6750.05 3,3750.2 14,3180.5 33,750______________________________________
The network of filaments that is utilized in the method and materials of the present invention must be formed by substantially completely filamentized strand, since strand that is not filamentized has voids between the filaments which attract and hold water. On the other hand, individual filaments retain only a very thin layer of water, perhaps several molecules thick, and this water spreads almost indefinitely along its surface since the angle of wetting on nascent glass approaches zero. Since this is necessary, the surface of the individual filaments most not be permanently poisoned by silicones, organic polymers, oils, or other nondispersible nonwetting materials. It is known that nascent glass fibers in water have identical negative charges which repell each other, and this phenomenon is believed utilized to disperse the individual filaments into a criss-crossing three dimensional fiber network that passes through or adjacent all interstitial voids in the mortar. The filaments used in the present invention, in an aqueous media, develop a zeta potential of mutually repelling negative charges on the individual filaments which causes them to repell each other and spread throughout the mortar.
It will be seen that a filament network wherein filaments extend through the product to adjacent the surface of the material will have utility in all types of inorganic cementitious materials, be they plastic mixes: such as mortars, cements, concrete, insulating cements, and pan cast products; or be they wet process products made from dilute slurries having no more than approximately 10% solids. Such processes include filter press processes and the Hatscheck process that is commonly used to produce cement pipe, cement board and pipe insulation, etc. In the case of plastic mixes, it becomes very difficult to mix more than approximately 1%, based on total solids, of glass filaments with the mixes as is apparent from the above table. Therefore, for plastic mixes, the preferred range will be from 0.01% to 1.0%. Also, as pointed out above, chopped strand may be included in these plastic mixes for strength considerations, in which case it is possible to use up to approximately 8% of chopped strand in addition to the amount of filaments given above. In the case of wet process products, it is, of course, possible to disperse greater amounts of the monofilaments throughout the greater amount of water that is being used. In such cases, it is possible to disperse up to approximately 10% based on solids, of chopped glass filaments into the water, so that in these processes it is possible to use from 0.01 to 10%. Also in these products, where it is desired to increase flexural strength, compressive strength and impact strength, it is possible to incorporate up to 10% of nonfilamentizable chopped glass strand. In general, the ware that is produced by filtration processes will comprise the following materials in parts by weight:
______________________________________Ingredients Broad Preferred______________________________________Cement (Portland) 100 100Filler (Sand) 10-200 30-100Glass monofilament 0.05-10 0.1-8.0Strands (glass) 0-10 2-5Organic fibers 0-10 2-5______________________________________
Where insulation products such as pipe insulation is to be made by the filtering process, the products may have a density up to 65 lbs./ft. 3 and will generally comprise the following solids on a weight basis:
______________________________________Ingredient Broad Preferred______________________________________Mineral fiber (mineral wool) 10-50 20-40Lightweight filler 0-30(Flyash) 10-20(Diatomaceous Earth) 2-10Cement (Portland) 10-30 15-20Clay 0-49 30-40Glass monofilaments .01-1.0 0.05-0.2Glass strand 0-10.0 1-5.0______________________________________
Where the insulation materials are to be made from the pan casting operations, the materials will generally comprise the following solids on a weight basis:
______________________________________Ingredient Broad Preferred______________________________________Mineral fiber 19-39 20-30Particulate filler 0-60 50-60(Sand)Hydraulic setting binder 3-60(Portland) 10-20(Slag) 10-50Glass monofilaments 0.01-1.0 0.05-0.2______________________________________
As previously indicated, the filament network of the present invention will have great application in concrete. Typical formulations for such concretes will generally comprise the following on a weight basis:
______________________________________Ingredient Broad Preferred______________________________________Sand 10-40 25-40Cement (Portland) 3-30 15-25Coarse Aggregate 30-59 40-60Glass Monofilaments 0.01-1.0 0.1-0.3Glass Strands 0-8.0 2-4______________________________________
To the above enough water (approximately 30 parts) to make a plastic mix is added; and when a lightweight product is desired, sufficient air entraining agent may be added to encorporate from 1/4 to 2 percent by volume of air in the product. AR glasses (alkali resistant glasses) may be made from various compositions and are now produced commercially with the compositions in mol percent of materials given below:
______________________________________Material Preferred Range______________________________________SiO.sub.2 66.6 62-75CaO 6.0 1-10Na.sub.2 O 15.2 13-21M.sub.2 O 1.8 13-21ZrO.sub.2 5.5 5-11TiO.sub.2 4.9 0-6.5Al.sub.2 O.sub.3 0-4Fe.sub.2 O.sub.3 0-5______________________________________
Such glasses are preferred glasses for the monofilaments where alkali containing cements are utilized.
It should be emphasized, that particularly beneficial results are had in dense mortars and concretes, with respect to an improvement in the freeze-thaw cycle by assuring that some voids exist when the mortars or concretes are first made. The desired porosity can be produced in various ways; but the combining of the filaments of the present invention and an air entraining agent is particularly desirable in assuring the results of the present invention.
While the invention has been described in considerable detail, I do not wish to be limited to the particular embodiments shown and described; and it is my intention to cover hereby all novel adaptations, modifications, and arrangements thereof which come within the practice of those skilled in the art to which the invention relates. | Inorganic mortars, cements, and concrete are subject to crazing, cracking and spalling when subjected to alternate freezing and thawing. The present invention significantly decreases this affect by providing a network of tiny glass filaments having a hydrophilic surface throughout the mortars and cements. Preferably there should be more than approximately 675 lineal inches of network forming filament per cubic inch of mortar. | 2 |
FIELD OF THE INVENTION
The invention relates generally to bipolar transistors and other semiconductor structures and their method of making. In particular, the invention relates to such structures having a lateral conduction path across the heterojunction between two different materials and to the method of making the structures.
BACKGROUND OF THE INVENTION
A heterojunction bipolar transistor is one in which the emitter, base and collector regions are made of different semiconducting materials. In contrast, a homojunction bipolar transistor is made of a single crystalline composition with the regions and junctions therebetween defined by variations in the doping type and concentrations. In particular, there has been much recent effort directed toward the fabrication of InP/GaInAs heterojunction bipolar transistors for inclusion as optical receivers or transmitters in InP/GaInAsP optoelectronic integrated circuits (OEICs). However, to date such heterojunction structures have been fabricated vertically, usually in some sort of mesa structure. Such a vertical structure makes it difficult to reduce parasitic effects, such as extrinsic base resistance and collector capacitance, and to planarize the mesa.
Thornton et al have recently disclosed a lateral bipolar heterojunction transistor in a technical article entitled "Unified planar process for fabricating heterojunction bipolar transistors and buried-heterostructure laser utilizing impurity-induced disordering" appearing in Applied Physics Letters, volume 53, 1988 at pages 2669-2671. In this device, a 0.1 μm undoped GaAs layer is formed between two thicker p-type Al 0 .4 Ga 0 .6 As layers. A central base region is then masked and Si is thermally diffused at 850° C. into the emitter and collector regions. Impurity-induced disordering causes the GaAs in the emitter and collector regions to convert to n-type AlGaAs while the thermal treatment simultaneously converts the GaAs in the base region to become p-type. However, this technique requires a large impurity density to accomplish the disordering and is further considered to be incompatible with optoelectronic fabrication technique.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a lateral bipolar heterojunction transistor.
A further object of the invention is to fabricate such a structure which is compatible with other optoelectronic fabrication procedures.
The invention can be summarized as the device and method of making of a lateral bipolar heterojunction transistor or other semiconductor structure in which a first semiconductor layer is epitaxially formed on an insulating substrate. The first layer is then masked and etched away in such a manner as to expose one or more clean crystalline side faces of the first layer as well as to expose the substrate. Then, in a regrowth step, a second epitaxial semiconductor layer is deposited onto the substrate and adjacent to the side face or faces of the first layer so as to be epitaxial both to the substrate on the bottom and to the first layer on the side. The lateral epitaxial structure across the heterojunction provides a low-resistance current path through a heterojunction of small area and therefore low capacitance.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-section of a transistor of a first embodiment of the present invention during an early fabrication stage, taken along a sectional line I--I of FIG. 2.
FIG. 2 is a plan view of the transistor of FIG. 1.
FIG. 3 is a plan view of the transistor of FIGS. 1 and 2 during a later fabrication stage.
FIG. 4 is a cross-section of the transistor of FIG. 3, taken along the sectional line I--I of FIG. 3.
FIG. 5 is a perspective view of the transistor of FIGS. 3 and 4.
FIGS. 6 and 7 are cross-sections of a transistor of a second embodiment of the present invention at two points in its fabrication, taken along sectional line VI--VI of FIG. 8.
FIG. 8 is a plan view of the transistor of the second embodiment during its fabrication.
FIG. 9 is a cross-sectional view of a third embodiment of the invention, which is an improvement of the second embodiment.
DETAILED DESCRIPTION
The first embodiment of the invention involves a lateral heterojunction bipolar transistor having an InGaAsP base layer epitaxially deposited on a substrate. The base layer is first photolithographically etched to roughly define the base and then further etched in situ to finally define the base before InP emitter and collector regions are regrown, that is, epitaxially grown on the substrate.
An example of the first embodiment is illustrated in FIG. 1. A 0.75 μm thick InGaAsP layer doped p-type with Zn to 5×10 17 cm -3 was epitaxially grown by low-pressure organometallic chemical vapor (OMCVD) deposition on an Fe-doped semi-insulating substrate 10 of (100)-oriented InP. The composition of the layer was In 1-x Ga x As y P 1-y , where x=0.29 and y=0.60, which corresponds to a wavelength of λ g =1.3 μm. Trimethylindium and trimethylgallium were used as the organometallic sources and arsine and phosphine as the hydride gas. Diethylzinc was used as the p-type dopant. The InGaAsP layer would eventually serve as the base. The base width was then roughly defined to a distance W R by photolithography and wet chemical etching, using H 2 SO 4 :H 2 O 2 :H 2 O (3:1:1 by volume), to form a roughly defined base 12. The exact value of W R is not critical but was set to about 10 μm. As illustrated in the plan view of FIG. 2, the roughly defined base 12 had an area of about 10×10 μm and was connected by a 2×2 μm neck 14 to a large base contact area 16.
The wafer was then covered with 200 nm of an SiO 2 layer 18 applied with a plasma-enhanced chemical vapor deposition method. As illustrated in the cross-section of FIG. 1 and the plan view of FIG. 3, two windows 20 of about 100×100 μm were opened in the SiO 2 layer 18 using an AZ1512 photolithographic mask and buffered HF as an etchant. The remaining portion of the SiO 2 layer 18 overlying the roughly defined base 12 had a width W B corresponding to the final base width, namely 2 μm. Widthwise sides 22 of the SiO 2 windows 20 extended further than corresponding sides 24 of the roughly defined base 12 so that the alignment was not critical.
The sidewalls of the roughly defined base 12 were then etched through the windows 20 by in situ melt-back to reduce the base width to approximately W B to thereby form an InGaAsP base 26, as illustrated in FIG. 4. The melt-back was accomplished in an LPE (liquid phase epitaxy) chamber, used for subsequent growth, by placing the wafer in contact at a first station with a Ga-In-As-P melt just prior to regrowth of the emitter and collector. At 588° C., the temperature of the melt-back, the melt was undersaturated with Ga, As and P and contained an excess of In. The melt would have been saturated at 583° C. The composition of the melt was calculated by the formulas given by Kuphal in an article entitled "Phase diagrams of InGaAsP, InGaAs and InP lattice matched to (100) InP" appearing in Journal of Crystal Growth, volume 67, 1984 at pages 441-457. If this melt had been used at 577° C., it would have yielded an InGaAsP layer lattice matched to InP with λ g =1.3 μm. A calibration run of the melt-back etch, using the same conditions as for the transistor fabrication, yielded an etch depth of 200 nm after 10 seconds for an undersaturation of ˜5° C., for which no undercutting of the SiO 2 was observed. The effectiveness of melt-back etching of selected crystallographic planes for providing optically flat surfaces has already been reported by T-K. Yoo et al in an article entitled "Surface-Emitting AlGaAs/GaAs DH LED with Buried-Window Cylindrical Lens" appearing in Japanese Journal of Applied Physics, volume 27, 1988 at pages L2357-L2360. It is noted that an attempt to use an etchant of H 2 SO 4 :H 2 O 2 :H 2 O (3:1:1 by volume), which selectively etches InGaAsP relative to InP, did not produce equally good transistor characteristics.
After the in situ etch-back, the sample remained in the LPE chamber but was moved to a second station therein and an InP layer was grown by LPE to simultaneously form an emitter region 32 and a collector region 30, corresponding to the two windows 20 in the SiO 2 layer 18. The InP was grown n-type with a concentration of 1×10 17 cm -3 of tin. The In-P melt at the second station was supersaturated in P. The InP was selectively grown only in the windows 20 because LPE growth has a much greater growth rate for epitaxial growth over the InP substrate 10 than over the amorphous SiO 2 layer 18. For the InP LPE growth, a two-phase solution method (polycrystalline InP immersed in the InP melt) was used to control the supersaturation. The melt homogenization temperature was 600° C. and the growth temperature was 588° C. The cooling rate during growth was maintained at 1.5° C./min so that surface planarization was obtained in about 1 minute. This epitaxial growth after removal of another layer is referred to as regrowth and has presented major technical difficulties in the prior art because the removal tends to introduce surface defects and therefore interface states. Past problems with regrowth have prevented selective area epitaxial growth. It is further noted that the in situ etch-back allowed the emitter and collector regions 30 and 32 to be not only epitaxial to the underlying InP substrate 10 but also to have an epitaxial interface with the InGaAsP base 26.
A perspective view of the fabricated transistor is shown in FIG. 5, which does not show the SiO 2 covering all the exposed substrate 10 and all portions of the base region 26 and base contact 16 and does not illustrate the non-rectangular shapes of the emitter and base regions 30 and 32, which correspond to the shapes of the windows 22. Ohmic contacts were applied by alloying the respective regions. A contact area was opened in the SiO 2 overlying the GaInAsP base contact using photolithography and buffered HF etchant. With the photoresist mask left in place, Au-Be was then evaporated to surface alloy part of the GaInAsP base contact. When the photoresist was removed, the Au-Be overlying the photoresist was lifted off. Contact areas in a new layer of photoresist were then photographically defined over the InP emitter and collector regions 30 and 32. Au-Ge-Ni was then evaporated to surface alloy part of the emitter and collector regions 30 and 32. Again, the excess Au-Ge-Ni was lifted off with the photoresist. Gold wires could have been ohmically bonded to the surface alloyed regions. However, the fabricated transistors were characterized using movable probes contacting the three contact areas.
There resulted a lateral bipolar heterojunction transistor having an emitter area adjacent the base of 0.75 μm×8 μm and a base width of 2 μm. The transistor exhibited a maximum current gain of 6 at low current levels in a common-emitter configuration. This gain was considerably better than that previously available in transistors with regrown active regions. However, it was still considerably less than that available from vertical mesa structures. The ideality factor was typically found to be 1.36. It is anticipated that surface passivation of the base region would enhance the minority carrier lifetime and thus the gain. Furthermore, it appears desirable to perform all processing in one chamber so that the junctions are never exposed to ambient conditions, that is, air.
The inventors have described the first embodiment in print in two technical articles by H-J. Yoo et al entitled "Fabrication of lateral planar InP/GaInAsP heterojunction bipolar transistor by selective area epitaxial growth" appearing in Electronics Letters, volume 25, 1989 at pages 191 and 192 and "Fabrication and characterization of lateral InP/InGaAsP heterojunctions and bipolar transistors" appearing in Applied Physics Letters, volume 54, 1989 at pages 2318-2320.
The above-embodiment involved in In melt-back etch performed in situ with the subsequent LPE regrowth of InP. Thereby, the sample remained in the environmentally and pressure controlled chamber between the etching and the regrowth. If the InP regrowth were performed by OMCVD, the in situ etching could be performed by an etching gas, such as HCl:HBr, injected into the OMCVD chamber. The chamber would not be vented to ambient between etching and regrowth. Similar in situ etching is available for molecular beam epitaxy (MBE).
The previously described embodiment relies upon regrowth of the emitter and collector. A second embodiment relies upon regrowth of the base. As illustrated in cross-section in FIG. 6, on a semi-insulating InP substrate 40, having the same composition and orientation as the substrate 10 of the first embodiment, there was grown by OMCVD an n-type InP layer 42 of 0.75 μm thickness doped with 1×10 17 cm -3 of silicon. A 0.2 μm SiO 2 layer 44 was then deposited by plasma-enhanced CVD. As illustrated in cross-section in FIG. 7 and in plan view in FIG. 8, the SiO 2 layer 44 was then photolithographically patterned to form two SiO 2 islands 46 and 48 corresponding to the later defined emitter and collector and their contact areas. The islands 46 and 48 in the vicinity of the base were separated by a groove 50 of width 2 μm. That is, the patterned and formed SiO 2 layer 44 acts as a mask comprising the two SiO 2 islands 46 and 48 separated by the base-region groove 50. The sample was then etched in HCl:H 3 PO 4 (3:1 by volume) for 8 to 10 seconds at 20° C. so as to completely etch through the InP layer 42. The etching produced a truncated V-shaped groove 52 (55° inclination angle) penetrating through the InP layer 42 between the islands 46 and 48 so as to expose a portion of the substrate 10. The etching also removed the surrounding InP layer 42 so as to produce an emitter region 54 and a collector region 56, both of n-type InP. The V-shaped groove 52 is illustrated as truncated but it may extend into the insulating substrate 40 and form a sharp point without affecting the invention.
The selective-area regrowth was then performed to form the base. A p-type InGaAsP layer 58 was grown by the same process and with the same composition as the InGaAsP regions 30 and 32 of the first embodiment. The InGaAsP layer 58 had a doping concentration from Mn of 1×10 18 cm -3 .
The regrowth formed not only the base and its contact area but also formed over the surrounding exposed InP layer 40. In an isolation etching step, the InGaAsP was photographically masked in the area of the emitter, the collector, the base, and the base contact. The exposed InGaAsP was then etched through with H 2 SO 4 :H 2 O 2 :H 2 O (3:1:1 by volume) so as to provide a transistor very similar to that illustrated for the first embodiment in FIG. 5 except for the inclined junctions between the base and emitter and between the base and collector. By means of the lift-off surface alloying technique described for the first embodiment, the emitter and collector regions 54 and 56 were provided ohmic contact areas of Au-Ge-Ni. Similarly, the V-groove area and the base contact area were coated with Au-Be. Alloying was done with a rapid thermal annealing system for 20 seconds.
The transistor was tested and it showed transistor action although the gain was approximately one. It is believed that performance will be improved with the structure of the third embodiment shown in FIG. 9. Just as in the second embodiment, the n-type InP layer 42 is epitaxially grown on the semi-insulating InP substrate 40. However, in the third embodiment a semi-insulating InP surface layer 60 is epitaxially grown on the n-type InP layer 42. A V-shaped groove is then etched through both the semi-insulating surface layer 60 and the n-type InP layer 42 with an anisotropic etchant. A base region 62 of p-type InGaAsP is then regrown in the groove. Contact vias 64 and 66 are formed through the semi-insulating surface layer 60, for example, by a heavy n-type ion implantation. Transistor performance should be improved because only a small edge of the V-shaped base region 62 is connected to the emitter or the collector region 42. | A method of fabricating a lateral bipolar heterojunction transistor and the transistor itself. In a first embodiment a first semiconductor layer of, for instance, InGaAsP is epitaxially grown on an insulating substrate with the subsequent selective area epitaxial regrowth of a second semiconductor layer, of for instance, InP on the substrate and adjacent to the base. The selective area regrowth forms the collector and emitter. Alternatively, the emitter and collector can be grown first and the base is regrown. In both cases, the semiconductor regrowth is epitaxial to the underlying substrate and to the semiconductor material at the side. Thereby, interface damage at the interface between the base and the emitter or collector is reduced so as to allow lateral minority carrier transport across the junction and small area junctions at low capacitance. | 7 |
FIELD OF INVENTION
This invention relates to a pulp mill bleach plant, and in particular, relates to a bleach plant construction and operation for use in a liquid effluent free bleached pulp mill.
BACKGROUND OF THE INVENTION
In a liquid effluent free bleached pulp mill, in which bleached pulp is formed by digesting cellulosic fibrous material and bleaching and purifying the pulp and in which spent pulping liquors are subjected to recovery and regeneration to form fresh pulping liquor, liquid effluents from the bleaching and purification operations (bleach plant effluent) are discharged into the recovery and regeneration operation.
The organic materials content of the bleach plant effluent is burned off in the recovery furnace of the recovery and regeneration operation and the aqueous phase is evaporated in the recovery and regeneration operation.
Owing to the high cost of evaporating water in a pulp mill, in the interests of minimizing operating costs, it is desirable to decrease the total volume of bleach plant effluent which must be discharged into the pulp mill recovery and regeneration operation and hence minimize the total evaporation load. It is also desirable that any bleach plant effluent volume decrease not significantly adversely affect the pulp quality obtained.
SUMMARY AND GENERAL DESCRIPTION OF INVENTION
In accordance with the present invention, there is provided a bleach plant operation in which water conservation is practised by controlling the use of wash water in the bleach plant, controlling the design and operation of washers, deckers and other mechanical devices used in the bleach plant, and controlling the inflow of water with chemicals.
The invention is particularly applicable to a bleach plant operation using a D/CEDED sequence, in which D/C means bleaching with an aqueous solution of chlorine dioxide and chlorine wherein the chlorine dioxide provides the majority of the available chlorine of the solution, D means bleaching with an aqueous solution of chlorine dioxide and E means caustic extraction with aqueous sodium hydroxide solution.
The bleach plant operation of the invention produces two liquid effluents from the bleach plant, one acid and the other alkaline. These effluents then pass to the recovery operation, preferably in accordance with the teachings of copending U.S. application Ser. No. 665,240 filed Mar. 9, 1976, entitled "Bleach Plant Filtrate Recovery," Douglas W. Reeve et al. (J32) now U.S. Pat. No. 4,039,372 and assigned to the assignee of this application.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic flow sheet of a liquid effluent free pulp mill;
FIG. 2 is a schematic flow sheet of a bleach plant in accordance with one embodiment of the invention; and
FIG. 3 is a schematic flow sheet of a pulp mill recovery and regeneration operation for use in this invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIG. 1, wood chips are digested in pulping liquor in a digester 1 and pass to a brown stock washer 2 wherein the pulp is freed from entrained pulping liquor. The pulp then passes to the bleach plant 3 for bleaching and purification with intermediate washing operations, using chlorine dioxide and chlorine, chlorine dioxide and sodium hydroxide solutions and water, and bleached pulp is recovered by line 4.
Spent pulping liquor from the brown stock washer 2 in line 5 and two aqueous effluents from the bleach plant 3 in line 6 pass to a recovery and regeneration operation 7 wherein combustible organic materials are combusted, pulping liquor is regenerated and sodium chloride, arising from the sodium atoms and the chlorine atoms in the bleach plant effluents, is removed by line 8 to prevent its build up in the system. Regenerated pulping liquor is recycled to the digester 1 by line 9.
In the aqueous effluent-free pulp mill as illustrated in FIG. 1, noxious aqueous effluents from the pulp mill are eliminated by discharge of the bleach plant effluents into the recovery and regeneration operation 7. The organic materials content of the bleach plant effluent is burned off in the recovery furnace of the recovery and regeneration operation 7 while the aqueous phase is evaporated.
In FIG. 2, there is illustrated a detailed flow sheet which includes a bleach plant 3 constructed and operated in accordance with the present invention for use in the effluent-free pulp mill illustrated in FIG. 1.
Referring to FIG. 2, a pulp treatment operation 10, incorporating a bleach plant designed to use a D/CEDED bleaching and caustic extraction sequence, includes a D/C bleaching tower 12, an E 1 caustic extraction tower 14, a D 1 bleaching tower 16, an E 2 caustic extraction tower 18 and a D 2 bleaching tower 20.
Drum washers are provided for each bleaching and caustic extraction stage including a D/C washer 22, an E 1 washer 24, a D 1 washer 26, an E 2 washer 28 and D 2 washer 30. Seal tanks are associated with each of the washers, including a D/C seal tank 32, an E 1 seal tank 34, a D 1 seal tank 36, an E 2 seal tank 38 and a D 2 seal tank 40.
An unbleached decker 42 in the form of a displacement washer is provided along with an associated seal tank 44. A similar bleached decker 46 is provided with an associated seal tank 48. Unbleached pulp and bleached pulp storage towers 50 and 52 respectively are provided. Screens and cleaners 54 and 56 are provided for unbleached pulp and bleached pulp respectively.
Unbleached pulp from the brown stock washing is passed by line 58 through the screens and cleaners 54 and via line 60 to the unbleached decker 42 and thence by line 62 to the storage tank 50. The pulp is passed from the storage tank 50 by line 64 to a sensor 66 which senses chlorine dioxide and chlorine required by the pulp. From the sensor the pulp passes by line 68 to the D/C bleaching tower 12.
After D/C bleaching, the pulp passes by line 70 to the D/C washer 22. From the D/C washer the pulp passes by line 72 through an E 1 mixer 73 and by line 74 to the E 1 extraction tower 14. The pulp passes from the E 1 tower 14 by line 76 to the E 1 washer 24 and thence by line 78 to a D 1 mixer 80 and by line 82 to the D 1 bleaching tower 16.
Following D 1 bleaching, the pulp next passes by line 84 to the D 1 washer 26 and by line 86 to the E 2 extraction tower 18. From E 2 extraction, the pulp passes by line 88 to the E 2 washer 28, by line 90 to a D 2 mixer 92 and by line 94 to the D 2 bleaching tower 20.
The pulp next passes by line 96 to the D 2 washer 30 before passage by line 98 to the screens and cleaners 56, by line 100 to the bleached decker 46 and by line 102 to bleached pulp storage 52. From the bleached pulp storage 52 the pulp is passed forward by line 104, such as, to a pulp drying machine, not shown.
Each of the washers 22, 24, 26, 28 and 30 and each of the deckers 42 and 46 is a rotating foraminous drum type having wash water shower bars 106 arranged adjacent the periphery thereof for the application of wash water to the pulp mat as it is transported on the drum surface, the water displaced from or passing through the mat passing to the appropriate seal tank by lines 108, 110, 112, 114, 116, 118 and 120 respectively. Wire cleaners 122 also are provided for each of the washers and deckers.
A complete countercurrent flow wash water system is utilized. Thus, fresh water passes to the pulp drying machine and pulp drying machine white water or other relatively fresh water is passed by line 124 to the showers 106 on the bleached decker 46 to displacement wash the pulp mat on the bleached decker. Part of the displaced liquor collected in the seal tank 48 is passed by lines 126 and 128 to the showers 106 of the D 2 washer 30, with the remainder passing by lines 126 and 130 for dilution of the pulp in line 98 before passage of the diluted pulp to the screens and cleaners 56.
Part of the liquor collected in the D 2 seal tank 40 passes by lines 132 and 134 to the washing showers 106 on the E 2 washer 28. Part of this liquor passes by lines 132 and 136 to pulp passing from the D 2 bleaching tower 20 to the D 2 washer 30 in line 96. Part of the collected liquor passes from the seal tank 40 by line 138 to the D 2 bleaching tower 20.
The liquor collected in the E 2 seal tank 38 partially passes by lines 140, 142 and 144 to the washing shower 106 of the D 1 washer 26. Another portion of this liquor passes by lines 140 and 146 to the pulp passing in line 88 from the E 2 extraction tower 18 to the E 2 washer 28. Further quantities of the collected liquor pass by line 148 to the E 2 extraction tower 18.
A small quantity of the liquor collected in the E 2 seal tank is used to dilute caustic extraction chemical and is passed to the caustic extraction chemical inlet feed line for this purpose by lines 140, 142 and 150.
The D 1 seal tank liquor is partially passed by line 152 to the D 1 bleaching tower 16. A portion of the liquor passes by lines 154, 156 and 158 to the showers 106 on the E 1 washer 24, while another portion of the liquor passes by lines 154, 156 and 160 to the first showers 106 on the D/C washer 22. Part of the D 1 seal tank liquor passes by lines 154 and 162 to the pulp in line 84 passing from the D 1 bleaching tower to the D 1 washer 26.
From the E 1 seal tank 34, part of the liquor passes by lines 163, 164 and 166 to the last showers 106 on the D/C washer 22 while another part passes by lines 163, 164 and 168 to the pulp passing in line 76 from the E 1 extraction tower 14 to the E 1 washer 24. Another part passes by line 170 to the E 1 extraction tower 14 while the remainder is discharged from the bleach plant by lines 163 and 172 for passage to the pulp mill recovery system.
Liquor from the D/C seal tank 32 partly passes by lines 174 and 176 to dilute the pulp passing by line 64 from the storage 50 to the sensor 66 with another part passing by lines 174 and 178 to the pulp passing by line 70 from the D/C bleaching tower 12 to the D/C washer 22. Another part of the liquor is passed by lines 180, 182 and 184 to the showers 106 of the unbleached decker 42. The liquor passing in this way of the showers 106 of the unbleached decker 42 is neutralized by sodium hydroxide solution fed by line 186. The remainder of the liquor passes out of the bleach plant 10 by line 188 for passage to the pulp mill recovery system.
The bleach plant effluents in lines 172 and 188 and the unbleached decker seal tank liquor in line 190 may be utilized as described in the aforementioned copending U.S. application Ser. No. 665,240 filed Mar. 9, 1976.
From the unbleached decker seal tank 44 liquor passes by line 190 for use as wash water in the brown stock washer of the pulp mill and liquor passes by line 192 to the unbleached pulp entering the unbleached screens and cleaners 54 by line 58.
It will be seen, therefore, that there is a general countercurrent flow of wash water and pulp through the pulp treatment operation 10.
Each of the cleaner showers 122 on the washers and deckers is fed by hot water. An inlet feed in line 194 feeds the cleaner 122 on the decker 42 by line 196, the cleaner 122 on the D/C washer 22 by lines 198 and 200, the cleaner 122 on the E 1 washer 24 by lines 198, 202 and 204, the cleaner 122 on the D 1 washer 26 by lines 198, 202, 206 and 208 the cleaner 122 on the E 2 washer 28 by lines 198, 202, 206, 210 and 212, the cleaner 122 on the D 2 washer 30 by lines 198, 202, 206, 210, 214 and 216 and the cleaner 122 on the bleached decker 46 by lines 198, 202, 206, 210 214 and 218.
Steam for heating purposes also is used. Thus, steam is fed by lines 220 and 222 to the E 1 mixer 72, by lines 220, 224 and 226 to the D 1 mixer 80, by lines 220, 224, 228 and 230 to an injection ring 232, and by lines 220, 224, 228 and 234 to the D 2 mixer 92.
To accommodate emergency overflow conditions, the seal tanks are connected in a countercurrent flow overflow arrangement. Thus, overflow from the bleached decker seal tank 48 passes by line 236 to the D 2 seal tank 40, the overflow from the D 2 seal tank 40 passes by line 238 to the E 2 seal tank 38, the overflow from the E 2 seal tank 38 passes by line 240 to the D 1 seal tank 36 and the overflow from the D 1 seal tank 36 passes by line 242 to the E 1 seal tank 34.
From the E 1 seal tank 34, the overflow passes by line 244 to a first spill storage tank 246 while overflow from the D/C seal tank 32 and the unbleached decker seal tank 44 pass to a second spill tank 248 by lines 249 and 250 and lines 252 and 250 respectively.
The overflow collected in the second spill tank 248 under emergency conditions may be returned to the system, after neutralization with sodium hydroxide solution, at a convenient time by lines 254, 256 and 258 while the overflow collected in the first spill tank 246 passes to the recovery system for use in brown stock washing or white liquor dilution.
With this seal tank overflow arrangement, when there is a temporary discharge of a pulp mat of lower than normal consistency from one washer to another, the excess water is returned to the preceding stage by seal tank overflow.
High density pumps are used for pumping the pulp through the bleach plant and such pumps use water-fed seal glands. Hot water fed from line 194 is used for such seal glands. Thus, seal glands of a pump 260 conveying the pulp by line 74 are fed by hot water in line 262, seal glands of a pump 264 conveying the pulp by line 82 are fed by hot water in line 266, seal glands of a pump 268 conveying the pulp by line 86 are fed by hot water in line 270, and seal glands of a pump 272 conveying the pulp by line 94 are fed by hot water in line 274. The pressure on the pump glands is controlled to minimize the flow of fresh water into the pulp passing through the pump.
Chemical feed for the bleaching and caustic extraction operations is provided by dilute sodium hydroxide solution, aqueous solutions of chlorine dioxide and chlorine and sodium hypochlorite solution. Sodium hydroxide solution in concentrated form (typically 50% by wt.) is fed by line 276 to the system and is diluted by the E 2 seal tank liquor in line 140 to the concentration required. The diluted sodium hydroxide solution then is passed by lines 278 and 280 to the pulp leaving the D/C washer 22. Sodium hydroxide solution also is passed by lines 278, 282 and 284 to the pulp leaving the E 1 washer 24 by lines 278, 282, 286 and 288 to the pulp leaving the D 1 washer 26, lines 278, 282, 286, 290 and 291 to the pulp leaving the E 2 washer 28. Dilute sodium hydroxide solution also passes by line 292 to the sodium hydroxide neutralization feed 186, provision also being made for emergency flow to the second spill tank 248 in line 293.
An aqueous solution of chlorine dioxide and chlorine is fed by line 294 to the pulp passing by line 64 from the pulp to storage 50 to the sensor 66. Sodium hypochlorite solution is fed by line 296 to the pulp in line 64.
An aqueous chlorine dioxide solution is fed by lines 298 and 300 to the pulp in line 82 before passage thereof into the D 1 bleaching tower 16. A mixer, not shown, is located immediately after the injection point of the chlorine dioxide solution to ensure even mixing of the solution with the pulp.
Chlorine dioxide solution is also fed by lines 298 and 302 to the pulp in line 94 before passage thereof into the D 2 bleaching tower 20. A mixer, not shown, is located immediately after the injection point of the chlorine dioxide solution to ensure even mixing of the solution with the pulp.
The chlorine dioxide solution fed by line 298 is one having a low concentration of dissolved chlorine whereby over 90% of the available chlorine content of the chlorine dioxide solution is provided by chlorine dioxide. A typical solution is one having a chlorine dioxide concentration of 10 gpl and chlorine concentration of 2 gpl.
The chlorine dioxide and chlorine solution fed by line 294 is one having a higher dissolved chlorine concentration than the chlorine dioxide solution in line 298, whereby about 70% of the available chlorine content of the solution is provided by chlorine dioxide and the remainder of the available chlorine is provided by the chlorine. A suitable solution contains about 10 gpl ClO 2 and about 6 gpl Cl 2 .
The sodium hypochlorite solution in line 296 breaks down under the acid condition of the pulp in line 64 to produce chlorine for the bleaching of the pulp in the D/C bleaching tower 12.
The chlorine dioxide solution in line 298, the chlorine dioxide and chlorine solution in line 294 and the sodium hypochlorite solution in line 296 all may be produced from a single chlorine dioxide and chlorine generator, for example, using the procedure outlined in U.S. Pat. No. 4,010,112. By the use of the latter chlorine dioxide generation system, the most efficient use of bleaching chemicals is obtained while the volume of water entering the bleach plant with chlorine dioxide and chlorine is minimized.
OPERATION
In operating the pulp mill system described above, steps are taken to ensure optimum bleaching, caustic extraction and washing, minimal consumption of water, energy and chemicals and the discharge of a minimal volume of liquid effluent, in the region of about 4000 U.S. gallons/air dried ton (USG/ADT) of pulp, as compared with the liquid effluent discharge from a conventional bleach plant operation of up to about 25,000 USG/ADT while the bleached pulp produced has properties at least comparable to those of pulp produced in conventional operations.
The fresh water consumption in the bleach plant is very small, with the principal inputs of fresh water to the bleach plant being pulp machine white water, chlorine dioxide solutions and the water in the unbleached pulp. Thus, not only does this bleach plant operation decrease the effluent volume to a level which is suitable for feed to the recovery system, but also decreases fresh water and hot water use from typically 20,000 USG/ADT to a negligible value.
Steam consumption is also decreased considerably from the conventional 5,000 to 7000 lbs/ADT to less than 1000 lbs/ADT, a considerable saving.
In the bleach plant operation, the pulp leaving line 64 is diluted with D/C seal tank filtrate in line 176 to the required consistency, typically about 4%, before mixing with the chlorine dioxide and chlorine solution in line 294, with additional chlorine being supplied by the sodium hypochlorite solution in line 296. In this way, the necessity for conventional chlorine gas injection is eliminated. While the use of sodium hypochlorite solution to provide part of the first stage chlorine requirement raises the pH of the D/C bleaching, it has been found that efficient bleaching chemical utilization is maintained even up to 1% of sodium hypochlorite (determined as available Cl 2 on the pulp).
Owing to the heat in the filtrate used in the dilution and arising from the elimination of conventional discharge of unbleached decker filtrate, the pulp fed to the bleaching tower 12 has a temperature of about 120° to 140° F (50° to 60° C). As is well known, pulp chlorination is usually carried out at temperatures less than 90° F (30° C) and higher temperatures increase the rate of reaction of the chlorine with the pulp. To control against overchlorination of the pulp with consequent strength losses, the chlorine dosage to the pulp is controlled in accordance with the sensor 66 which senses the kappa number of the pulp passing therethrough. This control, which may be by an optical or oxidation-reduction potential sensor, also results in no residual chlorine values and effective chemical usage.
The D/C bleaching tower 12 may be a conventional upflow tower having about 30 to 60 minutes retention time or a two-stage upflow-downflow tower with a retention time of about 20 minutes in the upflow and 0 to 25 minutes in the downflow. The variation in retention time achieved by an upflow-downflow tower allows ready compensation for variations in temperature and %ClO 2 substitution.
The substitution of chlorine dioxide for about 70 percent of the chlorine in the first stage bleaching operation is an important feature of the bleach plant operation. Since all the sodium and chlorine atoms in the recovered effluent must be matched, providing part of the oxidizing power with chlorine dioxide decreases the total chlorine atoms and hence the required matching sodium atoms, enabling the overall quantity of sodium hydroxide required to be decreased.
It follows, therefore, that the use of 70/30 D/C bleaching decreases the total quantity of sodium chloride discharged by the recovery system as compared with 100% C. Hence, any detrimental effects which may result from the discharge of sodium chloride containing liquors into the recovery system are decreased.
The use of 70/30 D/C first stage bleaching also produces brighter, stronger pulp with greater stability to yellowing with age as compared with 100% C first stage bleaching and results in an improved yield of bleached pulp.
In each of the other stages, conventional towers are used, operating at conventional temperatures of about 160° F (70° C), while the consistency is about 13%, which is higher than the conventionally achieved value of 10 to 12%.
The use of the E 2 seal tank filtrate to dilute the 50% NaOH solution for use in the system results in water and steam savings, the resulting solution being hotter than is usually used. It is also preferred to use a concentration of about 10 to 13% NaOH, which is more concentrated than conventionally used.
In the countercurrent washing operation, the wash water for a given stage is obtained from the seal tank of the following stage. Good washing is required on the E 1 washer to minimize the carry over of E 1 stage solids which would result in increased chlorine dioxide consumption in the D 1 stage. Hence a dilution factor of at least 3 is used in the E 1 washer and on all other washers a dilution factor of at least 2 is used.
The showers 106 on each of the washers are placed and oriented for optimum wash water distribution on the pulp mat and hence most efficient washing on each of the washers. The washer size is such as to provide a consistency of at least 13% on each washer for greatest washing efficiency.
The washing on the D/C washer is split between first D 1 filtrate and then E 1 filtrate with the E 1 filtrate application being controlled to about 75% of the water contained in the pulp mat in order to prevent passage of E 1 filtrate through the mat and into the D/C filtrate. The presence of E 1 filtrate in the D/C filtrate increases chemical consumption in the D/C stage and operation in the described manner avoids this problem.
On each of the washers an air doctor is used in place of a conventional external water-fed hydraulic doctor to remove the pulp mat from the screen after washing, although it may be possible to use a hydraulic doctor which uses filtrate recycled within the particular stage.
The wire cleaning showers 122 which are used in place of conventional hydraulic doctors which also remove the pulp mat from the washer screen are high pressure low volume wire cleaning showers. Each of the wire cleaning showers 122 is timer controlled so that they operate for only a small percentage of the time in order to decrease fresh hot water usage, typically to an overall volume of about 10 USG/min on the D/C and E 1 washers and to an overall volume of about 5 USG/min on the D 1 , E 2 and D 2 and bleached decker washers. Conventional hydraulic doctors use about 100 USG/min.
The use of hot water on the showers 122 decreases the thermal shock of conventional cold water hydraulic doctors, thereby improving the effective washer life and decreasing the overall steam heating requirement.
The liquid level in the bleached decker seal tank 48 is controlled by the addition of pulp machine white water in line 304 while the levels in the seal tanks 32, 34, 36, 38 and 40 are controlled by level control valves which feed the shower water to the preceding stage, providing a positive control on these levels, in place of the conventional overflow system. The seal tanks only overflow under emergency conditions.
The seal tanks have a tangential drop leg entry. The use of tangential entry releases entrained air and minimizes foaming tendencies. A parallel tangential entry of overflow from the following seal tank may be used to prevent reverse overflow.
The seal tanks are sized to allow sufficient time for entrained air separation, the sizing typically being such as to provide a filtrate retention time of about 120 seconds for the unbleached decker, D/C and E 1 seal tanks and of about 60 seconds for the D 1 , E 2 , D 2 and bleached decker seal tanks. A large freeboard space also is provided in each seal tank to allow for air separation, typically about 8 feet.
Turning now to consideration of FIG. 3, there is illustrated a bleached kraft pulp mill operation in which the overall material flow within an effluent-free pulp mill is illustrated. With the elimination of the toxic effect of bleach plant effluent by introducing the same to the pulp mill recovery operation, black liquor condensates become the potential dominant effluent. While the total BOD of the black liquor condensates is moderate, typically about 20 lbs of methanol ADT of pulp, when compared with that of bleach plant effluent, within the context of an "effluent-free" pulp mill, the value is quite high.
In the pulp mill operation illustrated in FIG. 3, the BOD level of the black liquor condensates is decreased to a very low level acceptable for discharge from the mill in the "effluent-free" environment. This is achieved by combining the most contaminated condensates and them steam stripping methanol from this mixture. The methanol removed in this way then may be used for its fuel value or otherwise. The stripped condensate then may be used in various locations in the mill.
As seen in FIG. 3, wood chips are fed by line 510 to a digester 512 to which white liquor is fed by line 514 and steaming vessel steam is fed by line 516. Pulp wash water also is fed to the digester 512 by line 518. The brown stock pulp is fed from the digester 512 by line 520 to a brown stock washer 522 to which wash water is fed by line 524. The washed pulp passes by line 526 through cleaners and screens 528 and line 530 to a bleach plant 532, such as that described above in connection with FIG. 2 and including the unbleached decker 42.
Wash water from the bleach plant 532 passes by line 534 to the cleaners and screens 528 and E 1 stage effluent from the bleach plant 532 passes by line 536 to join the wash water in line 524 passing to the brown stock washer 522. Wire cleaning water also passes to the cleaners and screens 528 by line 538.
Chlorine chemical preparation 540 provides chlorine dioxide and chlorine solutions to the bleach plant 532 by line 542 and sodium hypochlorite solution by line 544. The chemical preparation is fed by water in line 545 and is typically in accordance with the aforementioned procedure of U.S. Pat. No. 4,010,112.
Sodium hydroxide for the bleach plant 532 is fed by line 546 while wash water in the form of pupl machine dryer white water is fed by line 548 to the bleach plant. Other inputs for the bleach plant 532 are heating steam by line 550 and washer screen cleaner water by line 552.
The bleached pulp passing out of the bleach plant 532 passes by line 554 to the pulp machine dryer 556. Bleached pulp exits the dryer by line 558 while any excess white water not required in line 546 is passed to sewer by line 560, while some moisture passes to atmosphere through the dryer stack 562. Water for a variety of purposes enters to pulp machine dryer 556 by line 563, including vacuum pump seal water, condensate cooler water, trim jet water and steam shower steam.
The dilute black liquor and flash steam from the digester 512 pass by lines 564 and 566 to black liquor evaporators 568. Additional heating steam is fed to the evaporators 568 by line 570. The black liquor evaporators takes the form of sextuple effect evaporators which produce concentrated black liquor which passes by line 572 to the recovery furnace 574. Various other liquid effluents are produced and these will be described further below. Moisture is lost through weak black liquor oxidation stack 576.
In the recovery furnace 574 all the organic materials are burned and there is formed a smelt in line 578 containing sodium carbonate, sodium sulphide, sodium chloride and sodium sulphate. Stack gases are vented by line 580. Steam is generated in the furnace and the blow down is passed by line 582 to the evaporators 568.
The smelt in line 578 then is passed to liquor preparation 584 wherein white liquor is regenerated. D/C effluent from the bleach plant 532 passes by line 586 to liquor preparation 584 for kiln scrubbing therein. Smelt spray water is fed to the liquor preparation 584 by line 588. Solid green liquor dregs are removed from the liquor preparation 584 by line 590 as are dregs from the causticization by line 592.
The white liquor resulting from chemical preparation passes to a salt recovery process 594 by line 596. In the salt recovery process, which typically may be that outlined in U.S. Pat. No. 3,950,217, solid sodium chloride is removed from the white liquor by an evaporative procedure and recovered by line 598. The concentrated white liquor is diluted by E 1 filtrate from the bleach plant 532 fed by line 600 to the desired concentration to the digester 512 by line 514, as described in our copending application Ser. No. 665,240 mentioned above.
Burkeite also deposited in the salt recovery process 594 passes by line 602 to the liquor preparation 584, while excess condensate from the salt recovery process 594 is passed to sewer by line 604. Water for salt leaching in the salt recovery process 594 is fed by line 605.
The only liquid effluents being sewered from the system are excess white water in line 560 and excess condensate from the salt recovery process in line 604. Both of these liquors are pure water and hence their discharge is not harmful.
As mentioned above, there are a number of condensates from the black liquor evaporators 568. Those most contaminated with methanol from the black liquor, the hotwell condensate, the flash heat double evaporator condensate and the sextuple surface condenser condensate pass by lines 606, 608 and 610 respectively to a methanol stripper 612 along with turpentine underflow from the digester 512 in line 614. In the methanol stripper 612, steam, fed by line 616, strips methanol from the contaminated condensate. The methanol is recovered by line 618 while the purified condensate passes by line 620 to the brown stock washer 522 for use as wash water therein.
Part or all of the purified condensate may be used in a variety of other locations within the mill, for example, in wire cleaning in the cleaners and screens 528, for chlorine dioxide adsorption in chemical preparation 540, or as wash water in the bleach plant, or by line 621 in the bleach plant of FIG. 2.
The condensate from the fifth and sixth effect evaporators in the black liquor evaporators 568 is passed by line 622 to liquor preparation 584, while condensate from the second, third and fourth effect evaporators being relatively free of contaminants may be discharged or may join with the purified condensate in line 620 by line 624.
SUMMARY
The present invention, therefore, provides a bleach plant process which results in a low efficient volume and yet produces good pulp quality. The present invention also provides a bleached kraft mill water utilization system which eliminates noxious aqueous effluents. Modifications are possible within the scope of the invention. | A pulp mill bleach plant operation having a low effluent volume, a low consumption of water, energy and chemicals, and yet provides efficient bleaching, caustic extraction and washing is described. Water conservation is practised by controlling the use of wash water in the bleach plant, controlling the design and operation of washers, deckers and other mechanical devices used in the bleach plant and controlling the inflow of water with chemicals. An aqueous polluting effluent-free pulp mill water utilization system is also described. | 3 |
FIELD OF THE INVENTION
This invention relates in general to molecular biological systems created with color beads and, more particularly to a means by which a micro-array reader can determine the colors used for encoding random beads.
BACKGROUND OF THE INVENTION
Ever since it was invented in the early 1990s (Science, 251, 767-773, 1991), high-density arrays formed by spatially addressable synthesis of bioactive probes on a 2-dimensional solid support has greatly enhanced and simplified the process of biological research and development. The key to current micro-array technology is deposition of a bioactive agent at a single spot on a microchip in a “spatially addressable” manner.
Current technologies have used various approaches to fabricate micro-arrays. For example, U.S. Pat. No. 5,412,087, issued May 2, 1995, McGall et al., and U.S. Pat. No. 5,489,678, issued Feb. 6, 1996, Fodor et al., demonstrate the use of a photolithographic process for making peptide and DNA micro-arrays. The patent teaches the use of photolabile protecting groups to prepare peptide and DNA micro-arrays through successive cycles of deprotecting a defined spot on a 1 cm×1 cm chip by photolithography, then flooding the entire surface with an activated amino acid or DNA base. Repetition of this process allows construction of a peptide or DNA micro-array with thousands of arbitrarily different peptides or oligonucleotide sequences at different spots on the array. This method is expensive. An inkjet approach is being used by others e.g., U.S. Pat. No. 6,079,283, issued Jun. 27, 2000, Papen et al., U.S. Pat. No. 6,083,762, issued Jul. 4, 2000, Papen et al., and U.S. Pat. No. 6,094,966, issued Aug. 1, 2000, Papen et al., to fabricate spatially addressable arrays, but this technique also suffers from high manufacturing cost in addition to the relatively large spot size of 40 to 100 μm. Because the number of bioactive probes to be placed on a single chip usually runs anywhere from 1000 to 100000 probes, the spatial addressing method is intrinsically expensive regardless how the chip is manufactured. An alternative approach to the spatially addressable method is the concept of using fluorescent dye-incorporated polymeric beads to produce biological multiplexed arrays. U.S. Pat. No. 5,981,180, issued Nov. 9, 1999, Chandler et al., discloses a method of using color coded beads in conjunction with flow cytometry to perform multiplexed biological assay. Micro-spheres conjugated with DNA or monoclonal antibody probes on their surfaces were dyed internally with various ratios of two distinct fluorescence dyes. Hundreds of “spectrally addressed” micro-spheres were allowed to react with a biological sample and the “liquid array” was analyzed by passing a single micro-sphere through a flow cytometry cell to decode sample information. U.S. Pat. No. 6,023,540, issued Feb. 8, 2000, Walt et al., discloses the use of fiber-optic bundles with pre-etched microwells at distal ends to assemble dye loaded micro-spheres. The surface of each spectrally addressed micro-sphere was attached with a unique bioactive agent and thousands of micro-spheres carrying different bioactive probes combined to form “beads array” on pre-etched microwells of fiber optical bundles. More recently, a novel optically encoded micro-sphere approach was accomplished by using different sized zinc sulfide-capped cadmium selenide nanocrystals incorporated into micro-spheres (Nature Biotech. 19, 631-635, (2001)). Given the narrow band width demonstrated by these nanocrystals, this approach significantly expands the spectral bar coding capacity in micro-spheres.
Even though the “spectrally addressed micro-sphere” approach does provide an advantage in terms of its simplicity over the old fashioned “spatially addressable” approach in micro-array making, there are still needs in the art to make the manufacture of biological micro-arrays less difficult and less expensive and to simplify the process for identifying the color spectrum used to encode the beads (micro-spheres) used in micro-array receivers.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a solution to the problems and fulfillment of the needs discussed above.
According to a feature of the present invention, there is provided an apparatus for calibrating a micro-array receiver comprising;
a micro-array receiver including a substrate having coated a biologically active region with a composition including a first set of micro-spheres modified with a biological probe and containing an optical bar code generated from at least one colorant associated with said micro-spheres; and
a calibration region associated with said substrate, said region being outside said biologically active region and having an area containing said optical bar code color.
ADVANTAGEOUS EFFECT OF THE INVENTION
The invention has the following advantages.
1. A robust means is provided by which a micro-array reader can identify the color spectrum used to encode micro-spheres (beads) used in random array structures.
2. A calibration color region is provided on the micro-array receiver having identifying marks adjacent thereto to facilitate location of the calibration region by the micro-array reader.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of an embodiment of the present invention.
FIG. 2 is a diagrammatic view of another embodiment of the present invention.
FIG. 3 is a block diagram of a system for utilizing the present invention.
FIG. 4 is a diagrammatic view of another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In general, the present invention relates to a biological analysis system including a micro-array receiver having random or predetermined array of biologically functional sites which can form a repetitive pattern on the receiver. An exemplary micro-array receiver is described in U.S. patent application Ser. No. 09/942,241, Chari et al., the contents of which are hereby incorporated by reference. A general description of the micro-array receiver will now be given but reference is made to the latter patent application for a more complete description.
The micro-array receiver includes a substrate coated with a composition comprising micro-spheres (beads) dispersed in a fluid containing a gelling agent or a precursor to a gelling agent, wherein the micro-spheres are immobilized in a random or ordered position on the substrate. The substrate is free of receptors designed to physically or chemically interact with the micro-spheres. One or more sub-populations of the population of micro-spheres contain a unique optical bar code generated from at least one colorant associated with the micro-spheres and including a unique biological functionality or probe which react with analytes with which they come in contact.
The distribution or pattern of micro-spheres on the substrate may be entirely random (a spatial distribution showing no reference or bias) or be attracted or held to sites that are pre-marked or predetermined on the substrate. Each micro-sphere in the array has a distinct signature based on color which may be derived from mixing three dyes representing the primary colors Red (R), Green (G), and Blue (B) to create thousands of distinguishable micro-spheres with distinct color addresses (unique RGB values, e.g., R=0, G=204, B=153). The micro-spheres are made with active sites on their surface to which are attached a specific bioactive probe. Therefore, each color address can correspond to a specific bioactive probe.
A micro-array or population of micro-spheres can include a few or hundreds or more of sub-populations of micro-spheres, where each sub-population comprises the same color code and the same bio-active probe. Each micro-array of micro-spheres occupies a sub-area of the substrate and is repeated in a pattern over the area of the substrate. The dimensional area of the micro-array sub-area may be comparable to the dimensional area of a microtiter well or multiple wells may overlay a micro-array sub-area.
The micro-spheres are preferably coated onto the substrate as disclosed in U.S. patent application Ser. No. 09/942,241, Chari et al.
In order to use a micro-array having bioactive probes to analyze an unknown biological target sample, the sample to be analyzed has to be nonselectively labeled by using fluorescent dyes or chemiluminescent active molecules.
A biological target sample is placed into contact with the micro-array bioactive probes. The fluorescently/chemiluminescently signals which result from the hybridization of the unknown biological target sample with bioactive probes on the surface of the coated micro-spheres are detected and analyzed by an electronic camera/image processor system.
The invention provides a robust means by which a micro-array reader can identify the color spectrum used to encode beads (micro-spheres) used in random array structures. The array reader will know, apriori, the color spectrum of the beads used to produce the array, and thus will be able to discern with greater accuracy the spectrum of the bead under investigation. An implementation may include a target that includes a region having a series of areas, each containing a specific bead color. The areas will be printed on the micro-array receiver, preferably in a linear array away from the diagnostic region. As envisioned, the reader will locate the calibration target through identifying datum(s) or fiducial mark(s) and determine the color spectrum of each region within the target. This concept provides a means to determine with high-accuracy the specific bead under investigation. The robust nature or higher-accuracy comes about because in a random array of colored beads, there is a finite probability that two or more beads will overlap (agglomerate). In this instance, the detector would integrate the signal from all the beads and produce a color signature that would be different from the signature of a stand alone one. With the calibration areas, software could determine the color signature from each unique color and combinations of each and could de-convolve the unique colors and thus identify the bead(s). Otherwise, in this instance, the agglomerated beads would have to be identified and ignored. This would reduce the diversity of the array.
It is understood that the calibration area would contain every color used to encode the beads and include small areas of these unique colors. Each area is preferably 500 um×500 um and more preferably 2 mm×2 mm. The areas can be created by various printing means including inkjet deposition.
Referring now to FIG. 1, there is shown an embodiment of the present invention. As shown, micro-array receiver 10 includes a biologically active area 12 containing colored beads 14 having attached biological probes distributed in a random or orderly way. Micro-array receiver 10 also includes, according to the invention, a calibration region 16 outside of said biologically active region 12 . Region 16 includes a plurality of discrete color areas 18 , each area containing one color corresponding to a color used in the colored beads. Thus, area 12 contains beads of fifteen different colors representing fifteen different biological probes, region 16 has fifteen areas 18 of fifteen colors matching the fifteen bead colors.
As shown in FIG. 2, the calibration region 16 is provided with identifier(s) (marks) 20 adjacent to region 16 to facilitate location of region 16 by a micro-array receiver reader.
Region 16 can be placed anywhere on the front or back of receiver 10 outside the region of biological activity.
FIG. 3 shows a block diagram of a system for utilizing the present invention. Block 30 represents a micro-array receiver after it has come into contact with a sample analyte containing one or more unknown biological targets that can hybridize biological probes on the receiver. Those probes that have been hybridized can be processed for luminescence or phosphorescence by reader 32 . Reader 32 also reads the color areas 18 in calibration region 16 or receiver 12 . Processor 34 can match the known colors from calibration region 16 with the colors read from the hybridized colored bead 14 to identify the unknown biological targets in the analyte.
FIG. 4 illustrates a micro-array receiver that can be used in the present invention. As shown, micro-array receiver 10 includes a pattern of 24 regions 60 in a matrix of 4 rows and 6 columns. Each region includes an identical micro-array of randomly distributed biological probe sites, a portion of which are shown in the exploded view. In this view, 16 different biological probes attached to micro-spheres are randomly distributed throughout the portion 62 of region 60 . According to the invention, each probe is attached to a micro-sphere of a color unique to that probe so that micro-spheres of 16 different colors are present in portion 62 . If, for example, an analyte containing each of the 16 complimentary targets to the 16 probes is brought into contact with portion 62 , the hybridization of the 16 targets with the 16 probes would produce luminescence or fluorescence of 16 different colors which are detected by an appropriate detection system. Calibration region 64 includes sixteen areas 66 each of a color corresponding to the sixteen colors unique to the probes attached to the micro-spheres.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
PARTS LIST
10 micro-array receiver
12 biological active area
14 colored beads
16 calibration region
18 discrete color areas
20 identifiers marks
30 micro-array receiver with color beads
32 reader
34 processor
60 pattern of 24 regions
62 16 probes
64 calibration region
66 16 areas | Apparatus calibrates a micro-array receiver. The apparatus includes a micro-array receiver including a substrate having coated a biologically active region with a composition including a first set of micro-spheres modified with a biological probe and containing an optical bar code generated from at least one colorant associated with the micro-spheres; and a calibration region associated with the substrate, the region being outside the biologically active region and having an area containing the optical bar code color. | 2 |
BACKGROUND OF THE INVENTION
The invention relates to a door for a vehicle, particularly a motor vehicle.
The German Auslegeschrift (DAS) No. 1,480,089 discloses a door having a frame surrounding a window cutout constituting an upper region, and a supporting device which is potted in a synthetic resin body constituting a lower region. Viewed from outside the door, this synthetic resin body extends upward as fas as the lower edge of the window cutout.
A door with its lower part made of plastic has the advantage of reducing the possibility of corrosion. It is precisely the lower part of the door which is most exposed to corrosion and this part is made of a material which does not exhibit a tendency to corrode as does sheet metal. In addition, the weight of the door is reduced, in comparison with the weight of a door made completely of metal. However, in the mass production of such a door, these advantages are offset by disadvantages which make it practically unfeasible. During the potting process, the upper area of the door--i.e., the part made of sheet metal--must also be placed in the mold, resulting in considerable expenditure for large molds which are occupied for long periods of time during curing.
This known construction is also unsatisfactory because any damage to the door, when mounted in a vehicle, makes it necessary to replace the entire door since the two areas cannot be separated from one another.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a door for a vehicle, particularly a motor vehicle, having an upper region provided with a window opening and made of sheet metal, and a lower region made of plastic material which exhibits all the advantages of the prior doors of this type and which can be manufactured at a cost which is acceptable, even for large scale mass production.
It is a further object of the present invention to provide a door of the type noted above which may be easily repaired, if damaged, without requiring replacement of the entire door panel.
These objects, as well as other objects which will become apparent from the discussion that follows are achieved, according to the present invention, by assembling the door from two prefabricated components which are separately manufactured and constitute the upper and lower door regions, respectively. The upper component is made of sheet metal, and the lower component is made of a suitable plastic which can be reinforced, for example by means of glass fibers. The components are connected together at the level of the vehicle bumper or bumpers by boundary zones on each component which overlap and face one another.
Thus, an essential feature of the vehicle door according to the present invention lies in the choice of the height of the connection between the two components. The connection is located at the level of the vehicle bumper, and hence of the bumpers of other vehicles, so that the overlapping boundary zones of the two components of the door automatically produce a reinforcement at this vulnerable level, as if a longitudinal member were present. Since the lower component naturally extends only up to this level, only small molds are required for its manufacture. Such molds may be uncomplicated, especially where this lower component is, in turn, constructed as a multi-component unit.
The fact that the lower component is initially manufactured separately from the upper component, and only later combined therewith, has the additional advantage that the lower component can easily be replaced if damaged.
The separate manufacture of the two components of the door according to the invention also has a favorable effect upon production in quite a different sense. Since the doors intended for various types of vehicles differ from one another primarily in their lower areas in the vicinity of the sill, the upper component used in the door according to the invention can be employed for all doors for different types of vehicles, whereby the individual shape of the door can be provided for the individual type of vehicle by selecting an appropriately prefabricated lower component, which is releasably connected with the upper component. A releasable connection will be understood to be any connection which can be released without destroying one of the two components of the door according to the invention. For example, adhesive connections can be used; in addition, rivets, screws, and even clips can be used to join the upper and lower components.
If the lower component extends with its boundary zones into the upper component of the door, the boundary zones may be constructed as reinforcing support shapes extending substantially horizontally--i.e., lengthwise in the door--which stiffen the door at this particularly critical bumper height. The door may also be stiffened at this level by providing on the lower component and externally-projecting, substantially horizontal support surface for the upper component.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-section through a vehicle door, according to the present invention, showing the leading edge of the door from its inside.
FIG. 2 is a cross-sectional view of a portion of the door of FIG. 1 taken along the line II--II.
FIG. 3 is a vertical cross-section through a vehicle door, according to the present invention, having a pocket for a window and a window crank disk.
FIG. 4 is a vertical cross-section through a vehicle door, according to an alternative embodiment of the present invention, having a pocket for a window and a window crank disk.
FIG. 5 is a side view of a vehicle having a door in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiment shown in FIG. 1, the door is constructed in the usual manner with an upper component 1 made of sheet metal with an outside panel 2 and an inside panel 3, as well as a lower component 4 made of an appropriate plastic. The lower part rests against the usual door sill 6 of a vehicle, stressing a door seal 5, when the door is closed. The two components 1 and 4, as indicated by the fact that they are made of different materials, are therefore manufactured separately and assembled as finished components in such a manner that boundary zones 7, which may be discontinuous if desired, of the lower component 4 are pushed upward from below into corresponding boundary zones 8 of the upper component 1. The upper and lower components 1 and 4 are joined together in the region of these boundary zones 8 and 7, respectively, by connecting means indicated at 9 and 10. As an example, the connecting means may be an adhesive or a number of rivets. Boundary zones 7, 8 are in the height range of the bumpers of the vehicle, assuming that the vehicle is provided with bumpers of at least approximately the same height so that, in its particularly vulnerable height range, the door is reinforced by the connecting area with a double wall thickness (produced by the overlapping boundary zones).
The design of the boundary zones 7 and 8 at the leading edge wall of the door is shown in cross-section in FIG. 2.
Reinforcement in this height range is also provided by a substantially horizontal surface 11 of the lower component 4 which supports the outside door panel 2. At this point, the lower component 4 projects slightly beyond outside panel 2.
As is already apparent from this description of the door according to the invention, the door is made of corrosion-resistant plastic in its lower area which is the area most susceptible to corrosion and damage; in addition, the lower component 4 is relatively easily removed from the door, making the door less expensive to repair.
In the embodiment shown in FIG. 1, the lower component 4 is also comprised of two parts 4' and 4", which are joined together in a plane parallel to the plane of the door, with their boundary zones 12 and 13 overlapping. Not only does this result in a simplification of the molds for manufacturing lower component 4, but as is discussed in greater detail with reference to FIG. 4, it also makes possible the provision of an insert which forms a support shape in the boundary zones 7 and 8.
In FIG. 1, the numerals 14 and 15 designate openings (weep holes) to allow water to escape from the door.
Turning to the embodiment according to FIG. 3, the door will be seen again to consist of two components 20 and 21, of which only the lower component 21 is made of plastic. It has basically the same form as the lower component 4 in FIG. 1, but in this case the cross section is through the middle of the door; i.e., at the point where a pocket 22 for the crank-operated window indicated by 23 must be provided. Also in this embodiment the boundary zones of the lower component 21 are extended to form a lengthwise support which reinforces the door. In addition, the outer boundary zones 24 and inner boundary zones 25 are extended by essentially horizontal walls or ribs 26, 27 or 28, 29, running across practically the entire width of the door, as well as by vertical walls or ribs 30 or 31, which constitute support channels open toward the crank-operated window 23. The upper wall 27 has an approximately hook-shaped projection 32 in this vertical cross section, by means of which, as indicated at 32', it fits over the wall 29 in the event of an impact, possibly after destruction of the crank-operated window. This produces a "hooking effect," which simultaneously allows the lower component 21 to become a closed support channel.
While in the embodiment according to FIG. 3, discussed above, the boundary zones 24 and 25 of lower door component 21 are in turn components of a side-member arrangement, in the design according to FIG. 4 the side-member arrangement is obtained by an insert 40 which is mounted between the outer boundary zone 41 and the inner boundary zone 42 of the lower component 43. This insert 40 extends partially into the upper component 44 and partially into the lower component 43 of the door, thereby effecting a reinforcement or stiffening of the door over a relatively large height range. The insert 40 also extends essentially over the entire width of the door. It is formed by horizontal and vertical walls or ribs in such manner that open-channel supports are produced facing the pocket 45 for the crank-operated window 46. This area of the insert 40, which projects into the lower door component 43, is provided on one side only with walls or ribs to form half-closed support members, and is provided also with a projection 48 facing toward the inside wall 47 of the lower component which, upon impact, abuts the inside wall 47 with its edge 49 over as great a length as possible.
FIG. 5 shows a vehicle in accordance with the invention wherein the upper door portion 51 and the plastic lower door portion 52 meet along a junction 50 which is at the same height h as the vehicle bumpers 53 and 54.
In all of the embodiments, the lower door component at its upper end projects slightly over or outward from the outside panel of the upper door component, thereby not only producing greater strength, but also blending the different finishes resulting from the use of different materials. Of course, a trim strip can be provided at this point, or all problems relating to the slightly different surfaces of the two components can be overcome by using different colors for the two different components.
While there have been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that various changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such embodiments as fall within the true scope of the invention. | A door for a vehicle, particularly a motor vehicle having a bumper, has an upper region made of sheet metal provided with a window opening and a lower region made of plastic material. Each region is formed by an individual, prefabricated component which is separately manufactured and subsequently assembled together with the other component. When assembled, the two components have overlapping, facing boundary zones which are connected together at the level of the vehicle bumper. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device. Specifically, the invention relates to a semiconductor device with densely stacked semiconductor chips and a manufacturing method thereof.
[0003] 2. Description of the Background Art
[0004] Most conventional methods of mounting a semiconductor chip(s) have employed die bonding of one semiconductor chip to a single lead frame. Referring to FIG. 36, a semiconductor chip 101 is attached directly onto a die pad 103 integrated with a lead frame by means of adhesive or double-faced tape. A terminal electrode (not shown) of the semiconductor chip and a lead terminal 104 are connected by a wire 105 and they are further encapsulated by an encapsulating resin for the purpose of protection from moisture, impact and the like. Although this type of semiconductor device can be manufactured in a simple manner and its many advantages have been proved, it has a problem of a low ratio of the semiconductor chip relative to a unit volume in which the semiconductor chip is housed.
[0005] Accordingly, as shown in FIG. 37, a semiconductor device has been proposed including two stacked semiconductor chips 101 a and 101 b (Japanese Patent Laying-Open No. 2000-156464). This semiconductor device includes a lower semiconductor chip 101 b attached to one frame 104 a by adhesive 107 and an upper semiconductor chip 101 a attached to the other frame 104 b . The semiconductor chips are further bonded to each other by adhesive 107 . Respective terminal electrodes (not shown) of the semiconductor chips and lead terminals (not shown) are connected by means of wires (not shown) and encapsulated by an encapsulating resin 106 . In plan view, the semiconductor chips of the semiconductor device shown in FIG. 37 mostly overlap one another with a small displacement therebetween. In this way, the semiconductor device shown in FIG. 37 achieves a dramatic densification as compared with the semiconductor device shown in FIG. 36.
[0006] Through never-ending progress in downsizing of semiconductor chips, a semiconductor chip is now almost thinner than a lead frame. Such semiconductor chips have become highly dense, while densification of a semiconductor device mounting these semiconductor chips is insufficient. In particular, current semiconductor devices are not thin enough as thinning thereof has rarely received attention. Then, with a rapid prevalence of mobile data terminals like mobile phone, digital camera, video camera and the like, there arise strong demands for downsizing and densification in consideration of the thickness of a semiconductor device. Downsizing and densification of a semiconductor device with its thickness reduced without increase in area would provide desirable effects not only to such uses as mentioned above but to many other uses.
SUMMARY OF THE INVENTION
[0007] The present invention aims to provide a semiconductor device and a manufacturing method thereof achieving downsizing and densification by reducing the thickness of the semiconductor device without increase in area.
[0008] According to a first aspect of the present invention, a semiconductor device has terminal electrodes arranged, in plan view, outside a region where semiconductor chips are arranged. The semiconductor device includes a lower semiconductor chip located to overlap in the range of height with the terminal electrodes, an upper semiconductor chip located above the lower semiconductor chip, a wire connecting the upper and lower semiconductor chips to the terminal electrodes, and an encapsulating resin encapsulating the upper and lower semiconductor chips and the wire. The encapsulating resin and the terminal electrodes have respective bottom surfaces coplanar with each other.
[0009] The semiconductor chips and the terminal electrodes are arranged so that the terminal electrodes do not increase the thickness of the semiconductor device by their full thickness dimension. Namely, the thickness of terminal electrodes does not affect the thickness of the semiconductor device or merely a part thereof adds the thickness of the semiconductor device. It is thus possible to make the semiconductor device thinner regardless of the thickness of a lead frame where the terminal electrodes are formed. Consequently, downsizing and densification of products such as mobile data terminal can be promoted. Further, as the bottom surfaces of the encapsulating resin and terminal electrodes are coplanar, the terminal electrodes can be affixed onto an adhesive tape to form the semiconductor device having the above-described structure and use the adhesive tape as an outer surface of the encapsulating resin serving also as a resin-leak-prevention sheet thereby accomplishing resin encapsulation, for example. In this way, manufacture can be simplified.
[0010] Regarding the semiconductor device according to the first aspect of the invention, the upper semiconductor chip may be supported by a die pad portion coplanar with the terminal electrodes and the lower semiconductor chip may be arranged without overlapping in plan view with the die pad portion, for example.
[0011] This structure enables the upper semiconductor chip to firmly be supported. The upper semiconductor chip together with the die pad portion may be bonded to the lower semiconductor chip. Alternatively, the upper and lower semiconductor chips may be separated to fill the space between the chips with the encapsulating resin. Here, “support” means that the chip is supported by the die pad portion by adhering them together using adhesive, die bonding material or the like.
[0012] Regarding the semiconductor device according to the first aspect of the invention, the lower semiconductor chip and the encapsulating resin may have respective bottom surfaces coplanar with each other and the bottom surface of the lower semiconductor chip may be exposed from the encapsulating resin, for example.
[0013] With this structure, it is possible, for example, to affix the lower semiconductor chip together with the terminal electrodes onto an adhesive tape so as to fabricate the semiconductor device, so that manufacture is simplified. Further, the lower semiconductor chip only may be used to support the upper semiconductor chip to eliminate the die pad portion, reducing a manufacturing cost.
[0014] Regarding the semiconductor device according to the first aspect of the invention, the upper semiconductor chip may be supported by a die pad portion located higher than the terminal electrodes, and the lower semiconductor chip may have its bottom surface encapsulated by the encapsulating resin, for example.
[0015] With this structure, the lower semiconductor chip is supported such that it suspends from the upper semiconductor chip supported by the die pad portion, and accordingly the lower semiconductor chip can be arranged inwardly spaced from the bottom surface of terminal electrodes. The lower semiconductor chip is thus encapsulated by the encapsulating resin to enable the entire semiconductor device to be protected from moisture, direct impact and the like.
[0016] The semiconductor device according to the first aspect of the invention is of QFN (Quad Flat Non-Lead Package) type having the terminal electrodes arranged outside to surround the semiconductor chips, for example.
[0017] The terminal electrodes arranged to surround the semiconductor chips and the semiconductor chips and the electrodes are nearly located. Consequently, wiring of the electrodes and chips becomes simplified. Then, there is a higher degree of freedom for partially overlapping two semiconductor chips.
[0018] Regarding the semiconductor device according to the first aspect of the invention, the upper and lower semiconductor chips may be rectangles respectively in shape, connection terminals of the semiconductor chips may be arranged along shorter sides opposing each other of the rectangles, and the upper and lower semiconductor chips being rectangles in shape may be arranged to cross each other in plan view, for example.
[0019] Connection terminals are thus distributed over four sides so that wires on the semiconductor chips are not closely located in space and never interfere with each other. In particular, for the QFN type semiconductor device with terminal electrodes surrounding the chips, the connection terminals arranged on four sides and the surrounding terminal electrodes can neatly be connected with short wires.
[0020] Regarding the semiconductor device according to the first aspect of the invention, the terminal electrodes arranged outside may be leads arranged along two opposing sides with the semiconductor chips therebetween, for example.
[0021] This structure can be used to manufacture a thin TSOP type semiconductor device in a simple manner easily, with manufacturing cost reduced by enhancement of efficiency and yield.
[0022] According to a second aspect of the invention, a semiconductor device is of TSOP (Thin Small Outline Package) type having semiconductor chips arranged between a first lead portion and a second lead portion provided respectively on two sides opposing in plan view. The semiconductor device includes a first die pad portion integrated with and noncoplanar with the first lead portion and located higher relative to a reference plane passing through central position between the highest surface and the lowest surface of the first and second lead portions, a second die pad portion integrated with and noncoplanar with the second lead portion and located lower relative to the reference plane, and a lower semiconductor chip supported by the first die pad portion and an upper semiconductor chip supported by the second die pad portion. The two semiconductor chips are partially overlapped and located to overlap in the range of height with the first and second lead portions.
[0023] The semiconductor chips and the terminal electrodes are arranged so that the terminal electrodes do not increase the thickness of the semiconductor device by their full thickness dimension. Namely, the thickness of the lead frame does not affect the thickness of the semiconductor device or merely a part thereof adds the thickness of the semiconductor device. It is thus possible to make the semiconductor thinner. Further, components are arranged symmetrically in the vertical direction with respect to the reference plane and accordingly thermal stress and residual stress are not likely to be uneven in the vertical direction. Then, distortion like warp and the like rarely occurs. The upper and lower semiconductor chips may be bonded or may be spaced with an encapsulating resin filling the gap therebetween. It is noted that “support” means that the die pad portion is directly bonded to one of the bonded semiconductor chips to support the chip, and means, from an all-round and dynamical point of view, that the two die pad portions cooperate to eventually support both semiconductor chips. The reference plane is in parallel with planes that constitute the lead portions.
[0024] Regarding the semiconductor device according to the second aspect of the invention, the first die pad portion may be provided to a first lead frame located including the first lead portion above the reference plane, and the second die pad portion may be provided to a second lead frame located including the second lead portion below the reference plane, for example.
[0025] With this structure, two stacked lead frames can be employed to manufacture a semiconductor device. Two semiconductor chips can thus be stacked readily and efficiently on the two lead frames.
[0026] Regarding the semiconductor device according to the second aspect of the invention, for example, the first die pad portion may be L-shaped including a first extension extending from an end of the first lead portion toward the second lead portion and a first opposing portion continuing from the first extension and extending in parallel with the first lead portion. The second die pad portion may be arranged in plan view opposite the first die pad portion and L-shaped including a second extension extending from an end of the second lead portion toward the first lead portion and a second opposing portion continuing from the second extension and extending in parallel with the second lead portion. The first extension and the first opposing portion may have their bottom surface supporting the lower semiconductor chip and the second extension and the second opposing portion may have their upper surface supporting the upper semiconductor chip.
[0027] Such L-shaped die pad portions can be used to manufacture a thin and dense semiconductor device efficiently.
[0028] Regarding the semiconductor device according to the second aspect of the invention, the first and second lead portions and the first and second die pad portions may be integrated into a common lead frame, the reference plane passing through center of thickness of the lead frame, the first die pad portion may support the lower semiconductor chip of the partially overlapped semiconductor chips, and the second die pad portion may support the upper semiconductor chip, for example.
[0029] This simple and plain structure can be produced with high yield and efficiency as well as an earlier delivery. In addition, as components are arranged symmetrically in the vertical direction with respect to the reference plane, warp caused by thermal strain, residual stress and the like is unlikely to occur.
[0030] Regarding the semiconductor device according to the second aspect of the invention, center of thickness of the first die pad portion and center of thickness of the second die pad portion are preferably spaced vertically from the reference plane in respective directions opposite to each other, each by a distance equal to the sum of a half of thickness of the lead frame and a half of thickness of an adhesive layer bonding the upper and lower semiconductor chips, for example.
[0031] A precise symmetry relative to the reference plane is thus maintained to achieve a great resistance to warp and the like described above.
[0032] According to the first aspect of the invention, a method of manufacturing a semiconductor device having terminal electrodes arranged, in plan view, outside a region where semiconductor chips are arranged, includes, an affix-onto-sheet step of affixing the terminal electrodes and a lower semiconductor chip onto an adhesive sheet, a semiconductor chip stacking step of bonding an upper semiconductor chip onto the lower semiconductor chip, a wire connecting step of connecting the lower and upper semiconductor chips respectively to the terminal electrodes by wires, a resin encapsulating step of encapsulating the terminal electrodes, lower semiconductor chip, upper semiconductor chip and wires arranged on the adhesive sheet by resin, and an adhesive sheet stripping step of stripping the adhesive sheet from components resin-encapsulated in the resin encapsulating step.
[0033] With this structure, the adhesive sheet on which the terminal electrodes and semiconductor chips are arranged can be used as a sheet for preventing resin leakage and forming the outer surface of encapsulating resin. Then, the thickness of terminal electrodes does not add the thickness of the semiconductor device or just partially adds the thickness of the semiconductor chip. A resultant thin semiconductor device can accordingly be manufactured simply and with a low cost.
[0034] Regarding the method of manufacturing a semiconductor device according to the first aspect of the invention, a die pad portion may be affixed onto the sheet together with the terminal electrodes and lower semiconductor chip in the affix-onto-sheet step to bond the upper semiconductor chip to the die pad portion in the semiconductor chip stacking step, for example.
[0035] The upper semiconductor chip in this structure is supported by the die pad portion so that the lower semiconductor chip can be positioned with a greater degree of freedom. Specifically, the lower semiconductor chip supported by an adhesive tape in course of manufacture may be exposed on the bottom surface after the manufacture. Alternatively, the lower semiconductor chip may be supported by being suspended from the upper semiconductor chip. Consequently, the lower semiconductor chip is spaced inward from the bottom surface and the outer surface is formed by the encapsulating resin and thus the structure resistant to moisture and impact can be achieved.
[0036] Regarding the method of manufacturing a semiconductor device according to the first aspect of the invention, only the terminal electrodes and a die pad portion may be affixed onto the adhesive sheet in the affix-onto-sheet step to bond the upper semiconductor chip to the die pad portion in the semiconductor chip stacking step, the upper semiconductor chip and lower semiconductor chip being bonded in advance to constitute stacked semiconductor chips, for example.
[0037] This manufacturing method may be used to position the lower semiconductor chip spaced inward from the bottom surface.
[0038] Regarding the method of manufacturing a semiconductor device according to the first aspect of the invention, only the lower semiconductor chip may be affixed onto the adhesive sheet in the affix-onto-sheet step to affix a die pad portion to which the upper semiconductor chip is bonded in advance onto the adhesive sheet together with the terminal electrodes, for example.
[0039] According to conditions of manufacture sites, thin semiconductor devices can efficiently be produced by using this manufacturing method. The upper and lower semiconductor chips may be bonded with adhesive or spaced with the gap therebetween filled with the encapsulating resin.
[0040] A method of manufacturing a semiconductor device according to the second aspect of the invention includes: a lead frame stacking step of stacking a first lead frame on a second lead frame, the first lead frame including a first lead portion and a first die pad portion extending in L-shape from an end of the first lead portion along periphery of a region where a lower semiconductor chip is arranged, the second lead frame including a second lead portion and a second die pad portion opposing the first die pad portion in plan view and extending in L-shape from an end of the second lead portion along periphery of a region where an upper semiconductor chip is arranged, the first and second lead portions opposing in plan view with the upper and lower semiconductor chips therebetween; a semiconductor chip bonding step of bonding the lower semiconductor chip to the first die pad portion and bonding the upper semiconductor chip to the second die pad portion; a welding step of welding together the first lead frame and the second lead frame at their overlapping portion; a wire bonding step of connecting the upper and lower semiconductor chips to a terminal electrode by a wire; a resin encapsulating step of encapsulating by means of a resin a region inside the overlapping portion being welded; and a cutting off step of cutting off a portion outside the resin encapsulated first and second lead portion and the upper and lower semiconductor chips in the resin encapsulating step.
[0041] This manufacturing method enables a thin and dense semiconductor device to be produced efficiently by using two lead frames and welding.
[0042] Regarding the method of manufacturing a semiconductor device according to the second aspect of the invention, sub steps of the lead frame stacking step and sub steps of the semiconductor chip bonding step are preferably combined and partially changed in their order to be performed, for example.
[0043] Depending on manufacture sites, it could be efficient to preliminarily bond a semiconductor chip to one die pad portion in the lead frame stacking step. Such a change in order of sub steps is preferably made over the main steps, not just in one main step as described above.
[0044] Regarding the method of manufacturing a semiconductor device according to the second aspect of the invention, the lead frame stacking step and the semiconductor chip bonding step may include as a whole a die bonding material arranging step of arranging a die bonding material bonding the upper and lower semiconductor chips to the first and second die pad portions, for example.
[0045] The die bonding material is desirably employed instead of adhesive with a high flowability since it inevitably occurs that one of the lead frames is caused to face downward or both lead frames are tilted. A manufacturing process can thus be constituted to provide a high stability.
[0046] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] [0047]FIG. 1 is a schematic perspective view showing a semiconductor device according to a first embodiment of the present invention.
[0048] [0048]FIG. 2 is a perspective view showing the semiconductor device in FIG. 1 in a stage of manufacturing method A with a lower semiconductor chip affixed to an adhesive sheet.
[0049] [0049]FIG. 3 is a perspective view of the semiconductor device in a following stage relative to the state in FIG. 2 with adhesive applied to a predetermined region of the semiconductor chip.
[0050] [0050]FIG. 4 is a perspective view of a lead frame having a lead and a die pad in a separate stage from those in FIGS. 2 and 3.
[0051] [0051]FIG. 5 is a perspective view of the semiconductor device in a stage having an upper semiconductor chip attached onto the die pad in FIG. 4.
[0052] [0052]FIG. 6 is a perspective view of the semiconductor device having the upper semiconductor chip in FIG. 5 bonded to be located above and cross the lower semiconductor chip in FIG. 3.
[0053] [0053]FIG. 7 is a perspective view of the semiconductor device in FIG. 1 in a stage of manufacturing method B with the lead frame and lower semiconductor chip bonded onto the adhesive sheet.
[0054] [0054]FIG. 8 is a perspective view of the semiconductor chip in the state in FIG. 7 with a predetermined region to which adhesive is applied.
[0055] [0055]FIG. 9 is a plan view showing the semiconductor device in FIG. 1 together with a surrounding lead frame that is in course of manufacture according to the first embodiment.
[0056] FIGS. 10 to 13 respectively show cross sections along A-A′, B-B′, C-C′ and D-D′ in FIG. 9.
[0057] FIGS. 14 to 17 respectively show cross sections of a semiconductor device according to a first modification of the first embodiment of the present invention corresponding to respective cross sections along A-A′, B-B′, C-C′ and D-D′ in FIG. 9.
[0058] FIGS. 18 to 21 respectively show cross sections of a semiconductor device according to a second modification of the first embodiment of the present invention corresponding to respective cross sections along A-A′, B-B′, C-C′ and D-D′ in FIG. 9.
[0059] [0059]FIG. 22 is a schematic perspective view of a semiconductor device according to a second embodiment of the present invention.
[0060] [0060]FIG. 23 is a cross sectional view of the semiconductor device according to the second embodiment.
[0061] [0061]FIG. 24 is a plan view of an upper lead frame in FIG. 22.
[0062] [0062]FIG. 25 is a plan view of a lower lead frame in FIG. 22.
[0063] [0063]FIG. 26 shows the upper lead frame in FIG. 22 supposing that its die pad portion has its bottom surface to which a lower semiconductor chip is attached.
[0064] [0064]FIG. 27 shows the lower lead frame in FIG. 22 supposing that its die pad portion has its upper surface to which an upper semiconductor chip is attached.
[0065] [0065]FIG. 28 is a plan view showing the upper lead frame in FIG. 24 and the lower lead frame in FIG. 25 that overlap each other.
[0066] [0066]FIG. 29 is a plan view showing the upper and lower lead frames to which respective semiconductor chips are attached and which are overlapped and spot-welded together.
[0067] FIGS. 30 to 33 respectively show cross sections along A-A′, B-B′, C-C′ and D-D′ in FIG. 29.
[0068] [0068]FIG. 34 is a plan view of a semiconductor device according to a third embodiment of the invention.
[0069] [0069]FIG. 35 shows a cross section along A-A′ in FIG. 34.
[0070] [0070]FIG. 36 is a cross sectional view of a conventional semiconductor device.
[0071] [0071]FIG. 37 is a cross sectional view of another conventional semiconductor device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0072] Embodiments of the present invention are now described in conjunction with the drawings.
First Embodiment
[0073] Referring to FIG. 1, a semiconductor device shown still has an adhesive sheet 8 used in manufacturing thereof that should be stripped off. In FIG. 1, a die pad 4 b , a lead 4 a as a terminal electrode, and a lower semiconductor chip 1 b are in contact with the upper surface of adhesive sheet 8 . It is noted that lead 4 a should be arranged having contact with adhesive sheet 8 while die pad 4 b may be in contact with the adhesive sheet or located above and separated from the adhesive sheet. Die pad 4 b and lead 4 a are identical in thickness and can be formed through stamping or the like from one sheet. An upper semiconductor chip l a is arranged having contact with adhesive 7 on lower semiconductor chip 1 b as well as adhesive 7 on die pad 4 b . Respective connection terminals (not shown) of upper and lower semiconductor chips 1 a and 1 b are connected to leads 4 a by wires 5 to provide a predetermined wiring. Encapsulating resin 6 secures and covers entirely these chips, terminals and wires except for the portion contacting the adhesive sheet for protecting them from moisture and external force.
Manufacturing Method A
[0074] Manufacturing method A of the semiconductor device shown in FIG. 1 is described. Referring to FIG. 2, lower semiconductor chip 1 b is affixed to adhesive sheet 8 . Then, as shown in FIG. 3, adhesive 7 is applied to a predetermined region on semiconductor chip 1 b . Referring to FIG. 4, in a separate flow from that shown through FIGS. 2 to 3 , a lead frame including die pad 4 b and lead 4 a is affixed to adhesive sheet 8 , adhesive 7 is applied onto die pad 4 b , and upper semiconductor chip 1 a is put thereon to be secured thereto. Then, upper semiconductor chip 1 a in FIG. 5 is aligned with respect to adhesive 7 in FIG. 3 such that upper semiconductor chip 1 a is positioned on and secured to adhesive 7 , and lead 4 a and die pad 4 b are then affixed to adhesive sheet 8 (FIG. 6). Through subsequent steps (not shown), respective connection terminals of upper semiconductor chip 1 a and lower semiconductor chip 1 b are coupled by wires to be encapsulated by means of an encapsulating resin and each component is fixed. Then, the adhesive sheet is peeled off. According to the first embodiment, the adhesive sheet is stripped off to expose the lead, the die pad and the lower semiconductor chip.
Manufacturing Method B
[0075] A modification of manufacturing method A discussed above, namely manufacturing method B is now described. Referring to FIG. 7, a lead frame including a lead 4 a and a die pad 4 b as well as a lower semiconductor chip 1 b are affixed to an adhesive sheet 8 . The semiconductor chip to which this embodiment is applied has its thickness almost identical to or smaller than that of the lead frame as described above, so that the top surface of semiconductor chip 1 b is nearly at the same height as, or lower than, that of lead 4 a and die pad 4 b shown in FIG. 7. Referring to FIG. 8, adhesive 7 is applied with an appropriate thickness onto a predetermined region of the top surface of lower semiconductor chip 1 b as well as the top surface of the die pad. An upper semiconductor chip 1 a is put on the adhesive to be fastened, producing an intermediate product having the structure shown in FIG. 6. Subsequent wiring and resin encapsulation steps are the same as those of manufacturing method A.
Structural Detail
[0076] The semiconductor device shown in FIG. 1 is described below in more detail. FIG. 9 is a plan view of the semiconductor device according to the first embodiment that is in course of manufacture including the edge portion of a lead frame 4 before cutting. The double line Lm extending through the middle of leads 4 a to surround two semiconductor chips 1 a and 1 b indicates the outer shape of a mold corresponding to the outer surface of a resin encapsulation. A cutting line for cutting out each semiconductor device is appropriately positioned in a region including the mold line outside the semiconductor device. A slit 12 spaced from the perimeter of leads is made for easily cutting out a semiconductor device. In an actual manufacture by manufacturing method B for example, tape-shaped lead frames and lower semiconductor chips are successively affixed to a tape-shaped adhesive sheet and accordingly respective intermediate products of semiconductor devices are manufactured one after another through a production line.
[0077] FIGS. 10 to 13 show respective cross sections along A-A′, B-B′, C-C′ and D-D′ in FIG. 9. Components that are exposed after the adhesive tape is removed are encapsulated and fastened by means of an encapsulating resin. Although FIGS. 10 to 13 show no wire connecting semiconductor chips la and 1 b with leads 4 a , the encapsulating resin has a thickness sufficient to encapsulate wires.
[0078] The structure described above houses a semiconductor chip between leads and a semiconductor chip is further arranged thereon to overlap it. Accordingly, it is possible to efficiently reduce the thickness of the semiconductor device without increasing area.
First Modification
[0079] A first modification of the first embodiment according to the present invention is described below. FIGS. 14 to 17 respectively show cross sections of a semiconductor device corresponding to those along respective lines A-A′, B-B′, C-C′ and D-D′ in FIG. 9. In the first modification, a die pad 4 b is processed such that it is shifted upward slightly. Naturally, according to the upward shifting of the die pad, upper and lower semiconductor chips 1 a and 1 b are both shifted upward. Other components are identical in structure to those of the first embodiment. An encapsulating resin thus extends under lower semiconductor chip 1 b . Therefore, when an adhesive sheet is removed, lower semiconductor chip 1 b and die pad 4 b are never exposed on the rear side.
[0080] The semiconductor device of the first modification is manufactured in the following way. In the stage shown in FIG. 7 of manufacturing method B explained above, lower semiconductor chip 1 b is not affixed to adhesive sheet 8 and only a lead frame including lead 4 a and die pad 4 b is affixed to the adhesive sheet. Upper and lower semiconductor chips 1 a and 1 b are then crossed and bonded with adhesive so as to integrate them in advance. The upper chip of the integrated semiconductor chips is placed on the die pad to which adhesive is applied, and fastened to the die pad.
[0081] Although the semiconductor device of the first modification has its thickness which is not so remarkably reduced compared with the semiconductor device in FIGS. 10 to 13 , the former semiconductor device is advantageous in that a more extensive protection from moisture and outer force is possible since the semiconductor chip is not exposed on the rear side.
Second Modification
[0082] FIGS. 18 to 21 respectively show cross sections of a semiconductor device according to a second modification of the first embodiment, corresponding to those along respective lines A-A′, B-B′, C-C′ and D-D′ in FIG. 9. The second modification is characterized by the difference in thickness between upper and lower semiconductor chips 1 a and 1 b as compared with the embodiment discussed above. Other components are identical in structure to those of the first modification. A die pad 4 b of the second modification is also shifted upward and thus the manufacturing method of the first modification can be applied.
[0083] With this structure, the present invention is applicable to any combination of various types of semiconductor chips. Accordingly, many semiconductor devices having a small thickness can be achieved with versatility.
Second Embodiment
[0084] Referring to FIG. 22, lead frames 14 and 15 include lead portions 14 a and 15 a and die pad portions 14 b and 15 b . While lead portions 14 a and 15 a actually have many lead pins, in order to show the entire structure plainly, respective lead pins are not depicted distinguishably. While lead portion 14 a and die pad portion 14 b are almost coplanar with each other, one of them may be shifted upward or downward. Die pad portion 14 b includes an extension 44 b and an opposing portion 54 b. Die pad portion 15 b of lead frame 15 also includes an extension 45 b and an opposing portion 55 b.
[0085] A semiconductor chip 1 b is adhered via a die bonding material 17 to die pad portion 14 b of the upper lead frame 14 while a semiconductor chip 1 a is adhered via die bonding material 17 to die pad portion 15 b of the lower lead frame 15 . Two semiconductor chips 1 a and 1 b are thus fastened and further adhered to each other by means of die bonding material 17 . A connection terminal (not shown) of the upper semiconductor chip 1 a and a lead pin (not shown) of lead portion 14 a are connected by a wire 5 . These components are entirely encapsulated by an encapsulating resin to protect the components in the semiconductor device from moisture and external force.
[0086] Referring to FIG. 23, die pad portion 14 b of the upper lead frame 14 supports the lower semiconductor chip 1 b via die bonding material 17 and die pad portion 15 b of the lower lead frame 15 supports the upper semiconductor chip 1 a via die bonding material 17 . Here, a reference plane P passes through respective centers of thicknesses of upper and lower lead frames 14 and 15 . One of wires 5 is coupled to die pad portions 14 b and 15 b for grounding. As shown in FIG. 23, two lead frames are displaced in the vertical direction relative to reference plane P and two overlapping semiconductor chips are arranged between those two lead frames. Consequently, semiconductor chips 1 a and 1 b and lead frames 14 and 15 do not overlap in plan view and thus the entire thickness is not the combination of respective thicknesses. In this way, the semiconductor device can have a reduced thickness.
[0087] A method of manufacturing the semiconductor device shown in FIGS. 22 and 23 is described. FIGS. 24 and 25 show upper and lower lead frames 14 and 15 respectively. Lead portions 14 a and 15 a and die pad portions 14 b and 15 b of respective lead frames 14 and 15 are formed between upper frames 14 c and 15 c and lower frames 14 d and 15 d . FIG. 26 shows that lower semiconductor chip 1 b is supposed to be attached to the bottom surface of die pad portion 14 b of upper lead frame 14 . FIG. 27 shows that upper semiconductor chip 1 a is attached to the top surface of die pad portion 15 b of lower lead frame 15 . In an actual manufacture, before these lead frames are overlapped, to only one of the lead frames, a semiconductor chip is attached. If the semiconductor chips are fastened to both lead frames respectively that have not been overlapped, any inconvenience would occur in alignment.
[0088] [0088]FIG. 28 is a plan view showing the positional relation between upper and lower lead frames 14 and 15 overlapping each other with no semiconductor chip attached thereto. Referring to FIG. 28, die pad portion 14 b of upper lead frame 14 is located above die pad portion 15 b of lower lead frame 15 . When lower semiconductor chip 1 b is attached to the bottom surface of die pad portion 14 b , lower semiconductor chip 1 b and die pad portion 15 b are nearly at the same height. Further, when upper semiconductor chip 1 a is attached to the top surface of lower die pad portion 15 b , upper semiconductor chip 1 a and die pad portion 14 b are nearly at the same height.
[0089] [0089]FIG. 29 is a plan view showing that respective semiconductor chips are attached to die pad portions 14 b and 15 b of two lead frames 14 and 15 (one chip to each die pad portion) and they are overlapped and spot-welded at four corners. Die bonding material is not shown here. The two lead frames are thus firmly coupled by the spot-welding and thereafter upper semiconductor chip 1 a and lower semiconductor chip 1 b are connected respectively to upper lead portion 14 a and lower lead portion 15 a by respective wires. The region enclosed by the mold line Lm shown in FIG. 29 is filled with an encapsulating resin to cover the upper side and the lower side and accordingly encapsulate semiconductor chips, wires and the like. Then, a semiconductor device is cut out along the cutting line Lc in FIG. 29.
[0090] FIGS. 30 to 33 are cross sections respectively along A-A′, B-B′, C-C′ and D-D′ in FIG. 29. It can be understood from these drawings that the thickness of a semiconductor device of TSOP type can be reduced by arranging two semiconductor chips in the region surrounded by lead frames. In addition, the manufacturing method of the second embodiment employing spot welding to accomplish efficient production is suitable for low cost and mass production of semiconductor devices.
Third Embodiment
[0091] [0091]FIG. 34 is a plan view of a semiconductor device according to a third embodiment of the present invention in an intermediate stage. FIG. 35 is a cross section along A-A′ of the semiconductor device shown in FIG. 34. A lead frame 24 includes lead portions 24 a and die pad portions 24 b and 24 c . Read portions 24 a on the right and left are located on the same plane. A reference plane P passes through the center of thickness of lead frame 24 . Die pad portion 24 b is processed such that it is shifted upward relative to the right lead portion 24 a and die pad portion 24 c is processed such that it is shifted downward relative to the left lead portion 24 a . The die pad portions are shifted by distance S as shown in FIG. 35 that is equal to the sum of a half of the thickness of lead frame 24 from reference plane P and a half of the thickness of a die bonding material 17 . A lower semiconductor chip 1 b is attached via die bonding material 17 to the bottom surface of up-shifted die pad portion 24 b and an upper semiconductor chip 1 a is attached via die bonding material 17 to the upper surface of down-shifted die pad portion 24 c.
[0092] Regarding the structure discussed above, the overlapping portions of two semiconductor chips and the lead frame do not overlap and semiconductor chips and the like are vertically symmetrical with respect to the lead frame. Accordingly, thermal strain and nonuniform stress distribution rarely occur and a great resistance to deformation like warp is accomplished. Additionally, there is no extra thickness of encapsulating resin.
[0093] Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | A semiconductor device and a manufacturing method thereof are provided with downsizing and densification achieved by reducing the thickness of the semiconductor device without increase in area. Terminal electrodes are arranged, in plan view, outside a region where semiconductor chips are arranged. A lower semiconductor chip is placed to overlap in the range of height with the terminal electrodes, an upper semiconductor chip is placed above the lower semiconductor chip, a wire connects the upper and lower semiconductor chips to the terminal electrodes, and an encapsulating resin encapsulates the upper and lower semiconductor chips and wire. The encapsulating resin has its bottom surface coplanar with the bottom surface of the terminal electrodes. | 7 |
REFERENCE TO PENDING PRIOR PATENT APPLICATION
[0001] This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 60/939,615, filed May 22, 2007 by Tov Vestgaarden for PERCUTANEOUS SPINAL FACET FIXATION DEVICE FOR FACET FUSION (Attorney's Docket No. VG-1 PROV), which patent application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to surgical methods and apparatus in general, and more particularly to surgical methods and apparatus for fusing spinal facets.
BACKGROUND OF THE INVENTION
[0003] Disc herniation is a condition where a spinal disc bulges from between two vertebral bodies and impinges on adjacent nerves, thereby causing pain. The current standard of care for surgically treating disc herniation in patients who have chronic pain and who have (or are likely to develop) associated spinal instability is spinal fixation. Spinal fixation procedures are intended to relieve the impingement on the nerves by removing the portion of the disc and/or bone responsible for compressing the neural structures and destabilizing the spine. The excised disc or bone is replaced with one or more intervertebral implants, or spacers, placed between the adjacent vertebral bodies.
[0004] In some cases, the spinal fixation leaves the affected spinal segment unstable. In this case, the spinal facets (i.e., the bony fins extending upwardly and downwardly from the rear of each vertebral body) can misengage with one another. The misengagement of the spinal facets can cause substantial pain to the patient. Furthermore, when left untreated, such misengagement of the spinal facets can result in the degeneration of the cartilage located between opposing facet surfaces, ultimately resulting in osteoarthritis, which can in turn lead to worsening pain for the patient.
[0005] Thus, where the patient suffers from spinal instability, it can be helpful to stabilize the facet joints as well as the vertebral bodies. The facet joints are frequently stabilized by fusing the spinal facets in position relative to one another.
[0006] In addition to providing stability, fusing the spinal facets can also be beneficial in other situations as well. By way of example but not limitation, osteoarthritis (a condition involving the degeneration, or wearing away, of the cartilage at the end of bones) frequently occurs in the facet joints. The prescribed treatment for osteoarthritis disorders depends on the location, severity and duration of the disorder. In some cases, non-operative procedures (including bed rest, medication, lifestyle modifications, exercise, physical therapy, chiropractic care and steroid injections) may be satisfactory treatment. However, in other cases, surgical intervention may be necessary. In cases where surgical intervention is prescribed, spinal facet fusion may be desirable.
[0007] A minimally-invasive, percutaneous approach for fusing spinal facets was proposed by Stein et al. (“Stein”) in 1993. The Stein approach involved using a conical plug, made from cortical bone and disposed in a hole formed intermediate the spinal facet joint, to facilitate the fusing of opposing facet surfaces. However, the clinical success of this approach was limited. This is believed to be because the Stein approach did not adequately restrict facet motion. In particular, it is believed that movement of Stein's conical plug within its hole permitted unwanted facet movement to occur, thereby undermining facet fusion. Furthermore, the Stein approach also suffered from plug failure and plug migration.
[0008] Thus there is a need for a new and improved approach for effecting spinal facet fusion.
SUMMARY OF THE INVENTION
[0009] The present invention provides a novel method and apparatus for effecting spinal facet fusion. More particularly, the present invention comprises the provision and use of a novel spinal facet fusion implant for disposition between the opposing articular surfaces of a facet joint, whereby to immobilize the facet joint and facilitate fusion between the opposing facets.
[0010] More particularly, in one form of the present invention, there is provided a spinal facet fusion implant comprising:
[0011] an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile characterized by a primary axis and a secondary axis; and
[0012] at least one stabilizer extending radially outwardly from the elongated body in the secondary axis;
[0013] wherein the elongated body has a length along the primary axis which is less than the combined width of the spinal facets making up a facet joint;
[0014] and further wherein the at least one stabilizer has a width which is sized to make a press fit into the gap between the spinal facets making up a facet joint.
[0015] In another form of the present invention, there is provided a method for fusing a spinal facet joint, the method comprising the steps of:
[0016] providing a spinal facet fusion implant comprising:
an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile characterized by a primary axis and a secondary axis; and at least one stabilizer extending radially outwardly from the elongated body in the secondary axis; wherein the elongated body has a length along the primary axis which is less than the combined width of the spinal facets making up a facet joint; and further wherein the at least one stabilizer has a width which is sized to make a press fit into the gap between the spinal facets making up a facet joint;
[0021] deploying the spinal facet fusion implant in the facet joint so that the elongated body is simultaneously positioned within both of the facets of the facet joint and the at least one stabilizer is positioned within the gap between the spinal facets; and
[0022] maintaining the spinal facet fusion implant in this position while fusion occurs.
[0023] In another form of the present invention, there is provided a spinal facet fusion implant comprising:
[0024] an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile which is characterized by a primary axis and a secondary axis;
[0025] wherein the elongated body has a length along the primary axis which is less than the combined width of the spinal facets making up a facet joint;
[0026] and further wherein the cross-sectional profile is non-circular.
[0027] In yet another form of the present invention, there is provided a method for fusing a spinal facet joint, the method comprising the steps of:
[0028] providing a spinal facet fusion implant comprising:
an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile which is characterized by a primary axis and a secondary axis; wherein the elongated body has a length along the primary axis which is less than the combined width of the spinal facets making up a facet joint; and further wherein the cross-sectional profile is non-circular;
[0032] deploying the spinal facet fusion implant in the facet joint so that the elongated body is simultaneously positioned within both of the facets of the facet joint; and
[0033] maintaining the spinal facet fusion implant in this position while fusion occurs.
[0034] In still another form of the present invention, there is provided a joint fusion implant comprising:
[0035] an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile characterized by a primary axis and a secondary axis; and
[0036] at least one stabilizer extending radially outwardly from the elongated body in the secondary axis;
[0037] wherein the elongated body has a length along the primary axis which is less than the combined width of the bones making up the joint;
[0038] and further wherein the at least one stabilizer has a width which is sized to make a press fit into the gap between the bones making up the joint.
[0039] In an additional form of the present invention, there is provided a method for fusing a joint, the method comprising the steps of:
[0040] providing a fusion implant comprising:
an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile characterized by a primary axis and a secondary axis; and at least one stabilizer extending radially outwardly from the elongated body in the secondary axis; wherein the elongated body has a length along the primary axis which is less than the combined width of the bones making up the joint; and further wherein the at least one stabilizer has a width which is sized to make a press fit into the gap between the bones making up the joint;
[0045] deploying the fusion implant in the joint so that the elongated body is simultaneously positioned within both of the bones of the joint and the at least one stabilizer is positioned within the gap between the bones; and
[0046] maintaining the fusion implant in this position while fusion occurs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:
[0048] FIGS. 1-3 illustrate fusion implants formed in accordance with the present invention;
[0049] FIGS. 4 and 5 illustrate a fusion implant being installed in a facet joint;
[0050] FIGS. 6-12 illustrate instrumentation which may be used to install a solid fusion implant in a facet joint;
[0051] FIGS. 13-26 illustrate a preferred method for installing a solid fusion implant in the facet joint;
[0052] FIGS. 27-28 illustrate instrumentation which may be used to install a hollow fusion implant in a facet joint; and
[0053] FIGS. 29-74 illustrate alternative fusion implants formed in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In General
[0054] Looking first at FIG. 1 , there is shown a novel spinal facet fusion implant 5 formed in accordance with the present invention. Fusion implant 5 generally comprises a body 10 and at least one stabilizer 15 .
[0055] Body 10 comprises an elongated element having structural integrity. Preferably the distal end of body 10 (and the distal end of stabilizer 15 as well) is chamfered as shown at 20 to facilitate insertion of fusion implant 5 into the facet joint, as will hereinafter be discussed. Preferably, and as seen in FIG. 1 , body 10 has a rounded rectangular cross-section, or an ovoid cross-section, a laterally-extended cross-section, or some other non-round cross-section, so as to inhibit rotation of body 10 about a longitudinal center axis. If desired, body 10 may include a plurality of barbs (i.e., forward biting teeth) 25 extending outwardly therefrom. Barbs 25 are designed to permit body 10 to be inserted into the facet joint and to impede retraction of body 10 out of the facet joint.
[0056] The at least one stabilizer 15 is intended to be received in the gap located between the opposing facet surfaces, whereby to prevent rotation of fusion implant 5 within the facet joint. In one preferred form of the present invention, two stabilizers 15 are provided, one disposed along the upper surface of body 10 and one disposed along the lower surface of body 10 . Stabilizers 15 preferably have a width just slightly larger than the gap between the opposing articular surfaces of a facet joint, so that the stabilizers can make a snug fit therebetween.
[0057] If desired, and looking now at FIG. 2 , fusion implant 5 may also be configured so that its body 10 lacks barbs 25 on its outer surface.
[0058] Alternatively, if desired, and looking now at FIG. 3 , fusion implant 5 may comprise a hollow body 10 having an internal cavity 30 . Hollow body 10 may also have a plurality of openings 35 extending through the side wall of body 10 and communicating with cavity 30 . Internal cavity 30 and openings 35 can facilitate facet fusion by permitting bone ingrowth into and/or through fusion implant 5 .
[0059] Fusion implant 5 is intended to be inserted into a facet joint using a posterior approach. The posterior approach is familiar to spine surgeons, thereby providing an increased level of comfort for the surgeon, and also minimizing the possibility of damage to the spinal cord during fusion implant insertion.
[0060] In use, and looking now at FIG. 4 , an instrument is first used to determine the vertical plane 40 of the facet joint. Identifying the vertical plane of the facet joint is important, since this is used to identify the proper position for a cavity 45 which is to be formed in the facet joint to receive the fusion implant.
[0061] To this respect it should be appreciated that at least one of the instruments comprises a directional feature which is used to maintain the alignment of the instrumentation with the vertical plane of the facet joint. By way of example but not limitation, a directional cannula may comprise a flat portion and the remaining instruments may comprise a flat portion on an opposite portion of the instrument so that the instruments may only be inserted through the cannula at 0 degrees and/or 180 degrees.
[0062] After the proper position for cavity 45 has been identified, a drill (or reamer, punch, dremel, router, burr, etc.) is used to form the cavity 45 in the facet joint. Cavity 45 is formed across vertical plane 40 so that substantially one-half of cavity 45 is formed in a first facet 50 , and substantially one-half is formed in its opposing facet 55 .
[0063] After cavity 45 has been formed in (or, perhaps more literally, across) the facet joint, fusion implant 5 is inserted into cavity 45 . See FIG. 5 . More particularly, fusion implant 5 is inserted into cavity 45 so that (i) body 10 spans the gap between opposing facets 50 , 55 , and (ii) stabilizers 15 extend between the opposing facet surfaces. Preferably, fusion implant 5 is slightly oversized relative to cavity 45 so as to create a press fit. Fusion implant 5 provides the stability and strength needed to immobilize the facet joint while fusion occurs. Due to the positioning of stabilizers 15 between the opposing facet surfaces, and due to the non-circular cross-section of body 10 , fusion implant 5 will be held against rotation within cavity 45 , which will in turn hold facets 50 , 55 stable relative to one another.
[0064] It should be appreciated that where the hollow fusion implant 10 of FIG. 3 is used, and where the implant is formed out of a sufficiently strong and rigid material, cavity 45 need not be pre-formed in the opposing facets. In this case, the hollow fusion implant can be simply tapped into place, in much the same manner that a punch is used.
[0065] Thus it will be seen that the present invention provides a new and improved fusion implant for facilitating facet fusion. This new fusion implant is able to withstand greater forces, prohibit motion in all directions and drastically reduce the risk of implant failure. The new fusion implant also eliminates the possibility of slippage during spinal motion, greatly improves facet stability and promotes better facet fusion.
[0066] It should be appreciated that the new fusion implant combines two unique “shapes” in one implant (i.e., the shape of body 10 and the shape of stabilizer 15 ) in order to limit motion in a multi-directional joint. More particularly, the shape of body 10 limits motion (e.g., in flexion/extension for the lumbar facets and in axial rotation for the cervical facets), while the shape of stabilizer 15 (i.e., the “keel”) rests between two bony structures (i.e., in the gap of the facet joint) and limits lateral bending. This construction eliminates the possibility of eccentric forces inducing motion in the facet joint.
[0067] Furthermore, it has been found that while the present invention effectively stabilizes the joint, it still allows the “micro motion” which is required for the fusion process to begin.
[0068] It should be appreciated that the new fusion implant may be manufactured in a wide range of different sizes in order to accommodate any size of facet joint. Furthermore, the scale and aspect ratio of body 10 , stabilizers 15 , barbs 25 , openings 35 , etc. may all be varied without departing from the scope of the present invention. Additionally, the new fusion implant may be constructed out of any substantially biocompatible material which has properties consistent with the present invention including, but not limited to, allograft, autograft, synthetic bone, simulated bone material, biocomposites, ceramics, PEEK, stainless steel and titanium. Thus, the present invention permits the surgeon to select a fusion implant having the appropriate size and composition for a given facet fusion.
Detailed Surgical Technique
Solid Fusion Implant
[0069] A preferred surgical technique for utilizing a solid fusion implant 5 will now be described. The preferred surgical technique preferably uses a guide pin 100 ( FIG. 6 ) a facet distractor 105 ( FIG. 7 ), a directional cannula 110 ( FIG. 8 ), a drill guide 115 ( FIG. 9 ), a cavity cutter 117 ( FIG. 9A ), an implant loading block 120 ( FIG. 10 ), an implant holder 125 ( FIG. 11 ) and an implant tamp 130 ( FIG. 12 ).
[0070] First, the facet joint is localized indirectly by fluoroscopy, or directly by visualization during an open procedure. Next, a guide pin 100 ( FIG. 13 ) is inserted into the gap between the opposing facet surfaces. The position of guide pin 100 is verified by viewing the coronal and sagittal planes. Then guide pin 100 is lightly tapped so as to insert the guide pin approximately 5 mm into the facet joint, along vertical plane 40 . In this respect it will be appreciated that the inferior facet is curved medially and will help prevent the guide pin from damaging the nerve structures.
[0071] Next, a cannulated facet distractor 105 is slid over guide pin 100 ( FIG. 14 ) so that it is aligned with the vertical plane of the facet joint. Then facet distractor 105 is lightly tapped into the facet joint, along vertical plane 40 ( FIG. 15 ).
[0072] Next, a directional cannula 110 is placed over facet distractor 105 ( FIG. 16 ). Then the tip of directional cannula 110 is pushed into the facet joint ( FIG. 17 ). Once the tip of directional cannula 110 has entered the facet joint, the directional cannula is lightly tapped so as to seat the cannula in the facet joint. This aligns directional cannula 110 with the vertical plane of the facet joint. After verifying that directional cannula 110 has been inserted all the way into the facet joint and is stabilized in the joint, facet distractor 105 is removed ( FIG. 18 ).
[0073] Next, a drill guide 115 is inserted into directional cannula 110 ( FIG. 19 ). Drill guide 115 is advanced within directional cannula 110 until a drill guide stop is resting on directional cannula 110 . Then, with drill guide 115 in place, irrigation (e.g., a few drops of saline) is placed into drill guide. Next, a drill bit 135 is used to drill a cavity in the inferior facet ( FIG. 20 ). This is done by drilling until drill bit 135 reaches the mechanical stop on drill guide 115 ( FIG. 21 ). Then drill guide 115 and drill bit 135 are pulled out of directional cannula 110 , drill guide 115 is rotated 180 degrees, and then drill guide 115 is reinserted into directional cannula 110 in order to drill the superior facet. With drill guide 115 in place, irrigation (e.g., a few drops of saline) is placed into drill guide 115 , and then drill bit 135 is used to drill a cavity in the superior facet ( FIG. 22 ). Again, drilling occurs until drill bit 135 reaches the mechanical stop on drill guide 115 . Then drill bit 135 is removed ( FIG. 23 ).
[0074] A cavity cutter 117 is then used to make an opening having the perfect shape for fusion implant 5 .
[0075] Using implant loading block 120 shown in FIG. 10 , fusion implant 5 is then inserted into implant holder 125 . Then implant holder 125 , with fusion implant 5 in place, is placed into directional cannula 110 ( FIG. 24 ). Next, implant holder 125 is lightly tapped so as to insert fusion implant 5 into the cavity created in the facet joint ( FIG. 25 ). Once the implant has been positioned in the cavity created in the facet joint, implant tamp 130 is inserted into implant holder 125 . Next, implant tamp 130 is lightly tapped so as to drive the implant into the cavity created in the facet joint ( FIG. 26 ). The implant is preferably countersunk 1-2 mm into the facet joint.
[0076] Then the foregoing steps are repeated for the contralateral facet joint.
[0077] Finally, implant tamp 130 , implant holder 125 and directional cannula 110 are removed from the surgical site and the incision is closed.
Detailed Surgical Technique
Hollow Fusion Implant
[0078] A preferred surgical technique for utilizing a hollow fusion implant 5 will now be described. The preferred surgical technique preferably uses guide pin 100 ( FIG. 6 ), facet distractor 105 ( FIG. 7 ), and an implant punch 140 ( FIG. 27 ).
[0079] First, the facet joint is localized indirectly by fluoroscopy or directly by visualization during an open procedure. Next, guide pin 100 is inserted in the gap between the opposing facet surfaces. The position of guide pin 100 is verified by viewing the coronal and sagittal planes. Then guide pin 100 is lightly tapped so as to insert guide pin 100 approximately 5 mm into the facet joint, along the vertical plane of the facet joint. In this respect it will be appreciated that inasmuch as the inferior facet curves medially, this will help prevent the guide pin from damaging the nerve structures.
[0080] Then the cannulated facet distractor 105 is slid over guide pin 100 so that it is aligned with the vertical plane of the facet joint. Facet distractor 105 is lightly tapped into the facet joint, along the vertical plane of the facet joint.
[0081] Next, implant punch 140 ( FIG. 27 ), with a hollow fusion implant 5 mounted thereto ( FIG. 28 ) is pushed (or hammered or otherwise advanced) downwards so as to drive hollow fusion implant 5 into the facet joint.
[0082] Finally, implant punch 140 and guide pin 100 are removed, leaving hollow fusion implant 5 in the facet joint, and the incision is closed.
Alternative Constructions
[0083] The configuration of fusion implant 5 may be varied without departing from the scope of the present invention.
[0084] In one configuration, and looking now at FIGS. 29-31 , there is provided a fusion implant 5 comprising a rounded rectangular elongated body and two stabilizers. Preferably, the body comprises a groove extending circumferentially around the exterior surface of the body.
[0085] Looking next at FIGS. 32-34 , there is shown a fusion implant 5 comprising a rounded elongated body, which is similar to the embodiment shown in FIGS. 29-31 , however, the elongated body has a different aspect ratio and the elongated body is formed with a substantially smooth outer surface (e.g., without grooves or barbs).
[0086] FIGS. 35-37 illustrate a fusion implant 5 having an elongated body which is similar to the elongated body shown in FIGS. 29-31 , but without a stabilizer and with an elongated body which is formed with a substantially smooth outer surface (e.g., without grooves or barbs).
[0087] FIGS. 38-40 illustrate a fusion implant 5 having an elongated body with a smaller radius on the rounded edges than the embodiment shown in FIGS. 29-31 . Furthermore, the elongated body is formed with a smooth outer surface.
[0088] FIGS. 41-43 illustrate a fusion implant 5 which is similar to the implant of FIGS. 29-31 , but with the main body having a substantially circular configuration.
[0089] FIGS. 44-47 illustrate a fusion implant 5 which is similar to the implant of FIGS. 29-31 and further comprises a through-hole extending through the elongated body. The through-hole allows a bone growth promoter to be packed through and across the width of the fusion implant, thereby enabling rapid fusion through the implant.
[0090] FIGS. 48-50 illustrate a fusion implant 5 which is similar to the implant of FIGS. 29-31 . However, in this embodiment, the grooves are replaced with barbs (i.e., forward biting teeth) extending around the surface of the body.
[0091] FIGS. 51-54 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 48-50 , however, the fusion implant comprises a hollow body having an internal cavity and plurality of openings extending through the side wall of the body and communicating with the cavity.
[0092] FIGS. 55-57 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 , however, the fusion implant comprises a hollow body having an internal cavity and plurality of openings extending through the side wall of the body and communicating with the cavity.
[0093] FIGS. 58-60 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 and further comprises a hole for attaching the implant to the facet joint. The attachment may be effected by K-Wire, suture, staple, screw or other fixation device.
[0094] FIGS. 61-64 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 and further comprises a hole for attaching the implant to the facet joint. The attachment may be effected by K-Wire, suture, staple, screw or other fixation device. Preferably, a screw is used to attach the implant to the facet joint.
[0095] FIGS. 65-68 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 and further comprises a hole for attaching the implant to the facet joint. The attachment may be effected by an integrated screw. Like FIGS. 29-31 , this embodiment may also comprise grooves.
[0096] FIGS. 69-71 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 and further comprises rectangular, sharp spikes for attaching the implant to the facet joint.
[0097] FIGS. 72-74 illustrate a fusion implant 5 which is similar to the embodiment shown in FIGS. 29-31 and further comprises round, sharp spikes for attaching the implant to the facet joint.
ADVANTAGES OF THE INVENTION
[0098] Numerous advantages are achieved by the present invention. Among other things, the present invention provides a fast, simple, minimally-invasive and easily reproduced approach for effecting facet fusion.
Applications to Joints Other than Facet Joints
[0099] While fusion implant 5 has been discussed above in the context of fusing a facet joint, it should also be appreciated that fusion implant 5 may be used to stabilize and fuse any joint having anatomy similar to the facet joint, i.e., a pair of opposing bony surfaces defining a gap therebetween, with the stabilizer of the fusion implant being sized to be positioned within the gap. By way of example but not limitation, the fusion implant may be used in small joints such as the fingers, toes, etc.
MODIFICATIONS OF THE PREFERRED EMBODIMENTS
[0100] It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention. | A spinal facet fusion implant comprising:
an elongated body having a distal end, a proximal end and a longitudinal axis extending between the distal end and the proximal end, the elongated body having a cross-sectional profile characterized by a primary axis and a secondary axis; and at least one stabilizer extending radially outwardly from the elongated body in the secondary axis; wherein the elongated body has a length along the primary axis which is less than the combined width of the spinal facets making up a facet joint; and further wherein the at least one stabilizer has a width which is sized to make a press fit into the gap between the spinal facets making up a facet joint. | 0 |
RELATED APPLICATION DATA
[0001] This application claims priority to Provisional Application Serial No. 60/466,949, filed May 2, 2003, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to fence covering systems, and in particular, to an apparatus and method for mounting onto and covering at least one side of existing or new fences.
SUMMARY OF THE INVENTION
[0003] A fence covering system includes a frame configured and dimensioned to cover a portion of an existing fence. A panel is connected to the frame to provide a visual effect. A connector secures the frame on a portion of the fence, the connector providing an attachment position for the frame.
[0004] Advantageously, the present invention provides an efficient, convenient and relatively inexpensive way of converting, for example, a “plain” see-through chain-link fence or other fence into a fence offering more privacy, noise reduction and an immediate upscale and decorative appearance. Such effect is achieved without the hassle and expense of excavating an existing fence, and in the case of new fences to be constructed, standard fence posts, piping and fittings provide a sufficient frame onto which a fence covering system according to the present invention may be mounted.
[0005] Further, the fence covering system according to the present invention is easily removable, so that alternate designs and configurations may be freely interchanged and installed as desired. Advantageously, the present invention may be adapted to be used with virtually any type of fence or fence frame, and is not limited to use with, e.g., chain-link fences.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] This disclosure will present in detail the following description of preferred embodiments with reference to the following figures wherein:
[0007] [0007]FIG. 1A is an exploded perspective view showing a panel frame and panel in accordance with one embodiment of the present invention;
[0008] [0008]FIG. 1B is an assembled perspective view showing a panel frame and panel in accordance with an embodiment of the present invention;
[0009] FIGS. 2 A-G are perspective views showing panel frames being assembled on a chain link fence in accordance with different embodiments of the present invention;
[0010] [0010]FIG. 3 is an assembled perspective view showing a panel frame with additional height in accordance with an embodiment of the present invention;
[0011] [0011]FIG. 4A is a perspective view showing panel frames cascaded in accordance with an embodiment of the present invention;
[0012] [0012]FIGS. 4B and 4D are perspective views showing adjustable mounting plates in accordance with an embodiment of the present invention;
[0013] [0013]FIG. 4C is a perspective view showing a panel frame mounted on a chain link fence in accordance with an embodiment of the present invention;
[0014] [0014]FIG. 4E is a perspective view showing mounting plates secured to poles of a fence in accordance with one embodiment of the present invention;
[0015] FIGS. 5 A-C are perspective views showing adjustable pole covers and ornamental poles used in accordance with an embodiment of the present invention;
[0016] [0016]FIGS. 6A-6L are perspective views showing a plurality of different assemblies to be employed in accordance with embodiments of the present invention;
[0017] [0017]FIGS. 7A-7C are perspective views showing hardware employed on gates in accordance with embodiments of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] [0018]FIGS. 1A and 1B depict an exemplary fence covering panel 100 according to an aspect of the present invention. Preferably, the fence covering panel 100 is constructed of a rigid but somewhat flexible and resilient material, e.g., aluminum, vinyl, plastic, etc. In one embodiment, the present invention is generally comprised of at least one panel frame 102 having an interior panel 104 fitted therein which may include, e.g., optional openings/perforations 106 , etc. It is to be noted that the interior panel 104 may include, for example, various graphics (e.g., “artwork”) on its outer face. In addition, the interior panel 104 may be constructed in various configurations and designs (e.g., picket or slot designs 108 ).
[0019] [0019]FIGS. 2A-2G show various alternative embodiments wherein two of the fence covering panels 100 are combined to be fitted over both sides of a chain-link fence 200 . It is to be noted that the chain link fence 200 shown here is for exemplary purposes only and use of the present invention with other types of fences may be contemplated.
[0020] In one embodiment, each covering panel 100 is placed over either side of the fence 200 and then joined to each other at, for example, a top end via, e.g., snaps, screws, bolts, etc. (not shown). In another embodiment, as shown e.g., in FIGS. 2B and 2C, one or more pairs of mounting plates 202 are first installed and fixed onto the fence 200 or a top fence bar 201 via, e.g., snaps, screws, etc. At least one of the pair of mounting plates 202 may include, for example, protrusions 204 shaped to at least fit through, for example, links of the chain-link fence 200 , and be mated with appropriately shaped receiving cavities (not shown) on a corresponding mounting plate 202 on the other side of the fence (see FIG. 2D). Alternatively, at least one of a pair of mounting plates 202 may be adapted for attachment on the top fence bar 201 (e.g., may have a hollow cavity formed therein shaped to receive a portion of the top fence bar 201 ) and then be attached to a corresponding mounting plate 202 on the other side of the top fence bar 201 . In these ways, for example, each mounting plate 202 may be snapped into place and secured onto the fence 200 as well as be secured to each other.
[0021] In yet another alternate embodiment, it is to be noted that each covering panel 100 may include attachment points for attachment of various mounting plates 206 thereon as desired (e.g., plates mounting over fence bar 201 or through the chain-link fence 200 ) that are removable and independently interchangeable as desired (see FIG. 2E).
[0022] Next, each covering panel 100 can then be attached to the fence 200 via each installed mounting plate 202 . For example, each covering panel 100 may be snapped, screwed onto, or otherwise fastened onto each mounting plate 202 . The mounting plates 202 also serve to ensure and simplify correct alignment of each covering panel 100 with each other and with respect to the fence 200 prior to installation of each covering panel 100 .
[0023] In yet another embodiment, each covering panel 100 is first attached to each other at a top end (via, e.g., screws, snaps, etc.) and then slidably installed over the fence 200 (see FIG. 2F). FIG. 2G shows a segment of two fence covering panels 100 according to the present invention as installed on, for example, both sides of the chain-link fence 200 . It is to be noted that each of the fence covering panels 100 may include a fastening means (not shown) to secure the panels 100 to the fence 200 . Such fastening means may comprise, e.g., a clip to secure the bottom of each panel 100 to the bottom of the fence 200 . Alternately, two covering panels are integrally formed to provide a single piece, which can be fitted over the top of a fence 200 . The two panels may be hingedly connected to fit over the fence and be attached to or through the fence at a lower portion.
[0024] [0024]FIG. 3 depicts an exemplary embodiment of the fence covering panel 100 having an optional extended detailing feature 300 according to an aspect of the present invention. The detailing 300 may comprise, e.g., railings, posts, arches, walls, etc. in any shape, size or configuration to extend the height of the overall fence as desired.
[0025] [0025]FIGS. 4A and 4B show exemplary arrangements wherein multiple fence covering panels 100 are installed on either sides of the fence 200 as well as adjacent to each other along the fence 200 . It is to be noted that the fence covering panels 100 may include, e.g., interlocking/mating features (not shown) for side-by-side attachment to each other when they are adjacently installed.
[0026] The installation of the panels 100 onto the fence 200 may be accomplished using, e.g., individual mounting plates 202 as described above or upper and lower adjustable mounting plates 400 and 401 , respectively. The upper and lower adjustable mounting plates 400 and 401 may be, for example, slideable to provide for adjustment of their length as desired along each side of the fence 202 (see FIG. 4B). Thus, in an alternate embodiment as shown in FIG. 4C, a single extended fence covering system 402 may be installed onto the fence 200 on appropriately extended adjustable mounting plates 400 and 401 (not shown).
[0027] In yet another alternate embodiment, FIG. 4D depicts installation of upper and lower adjustable mounting plates 400 and 401 on a standard fence frame comprising fence posts 404 and top fence bar 201 . It is to be noted that in this embodiment, the lower adjustable mounting plate 401 may be used alone without an additional bottom fence bar for reinforcement. FIG. 4E shows yet another embodiment wherein frame mounting plates 406 are installed onto the top fence bar 201 and a bottom fence bar 408 for mounting of the fence covering panels 100 .
[0028] Thus advantageously, it is to be noted that it is not required to construct an actual fence in its entirety for installation and attachment of a fence covering system according to the present invention. Instead, a simple fencing frame can provide sufficient structural support for installation, mounting and utilization of the present invention.
[0029] [0029]FIGS. 5A-5C show exemplary embodiments wherein a fence post covering system 500 is installed onto a fence 200 . It is to be noted that the fence post covering system 500 may be used to cover fence posts or fences of any type, and is not limited to chain-link fences. In one embodiment, the fence post covering system 500 is comprised of at least one fence post mounting plate 501 and at least one fence post covering panel 503 . It is to be noted that the mounting plate 501 may be adapted so as to be removably attachable to a fence post (see FIG. 5A) or at any point along the fence (see FIG. 5B). In another embodiment as shown in FIG. 5C, each fence post covering panel 503 includes removable mounting pieces 505 attached therein that are shaped/positioned accordingly for attachment of the panel 503 to the fence post 404 or to any point along the fence 200 .
[0030] [0030]FIGS. 6A-6L depict various embodiments of a combined fence and fence post covering system according to the present invention. It is to be noted that the fence and fence post covering system may be adapted for use on either one of both sides of the fence 200 as desired. Preferably, each of the components of the fence and fence post covering system is constructed of a rigid but somewhat flexible and resilient material, e.g., aluminum, vinyl, plastic, etc.
[0031] In FIG. 6A, a combination fence and fence post covering system 600 is shown comprising fence post coverings 503 , a side panel 601 and a cap 603 . The fence post coverings 503 may be attached to each fence post 404 via e.g., fence post mounting plates 501 or mounting pieces 505 , as described above. The side panel 601 is preferably cut and sized to fit between each post covering 503 and may be attached to the fence 200 by e.g., partially inserting/sliding each edge 602 of the panel 601 under/into each post covering 503 . The cap 603 is also preferably cut and sized to fit between the post coverings 503 and preferably has an interior cavity 604 appropriately sized/shaped to fit over and receive the top fence bar 201 . The cap 603 may be secured if desired to the fence bar 201 and/or to either or both of the fence covering posts 503 via any conventional means e.g., suction, snaps, clips, bolts, screws, etc.
[0032] Alternatively, the cap 603 may be attached to the fence bar 201 via mounting onto at least one cap mount 605 (see FIG. 6B). Preferably, for optimal stability, at least two cap mounts 605 are used for mounting the cap 603 thereon. Each cap mount 605 may be attached to the fence bar 201 by any conventional means, e.g., screws, bolts, snaps, suction, etc.
[0033] In another embodiment as shown in FIG. 6C, a modified post mount 607 may be provided for attachment to a top end of the fence post 404 . Preferably, each post mount 607 is designed to secure at least one or, alternatively, both post coverings 503 on either side of the fence 200 , as well as the cap 603 to the fence 200 . The post mount 607 may be affixed to the post 404 via conventional means, e.g., bolts, pressure screws, snaps, etc. It is to be noted that the modified post mount 607 may be used in a similar fashion on a bottom end of the fence bar 404 .
[0034] It is to be noted that the side panel 601 may be comprised of individual panels 609 that are integrated (e.g., attached) to each other (see FIG. 6D). The individual panels 609 may be pre-cut in various sizes/shapes and may each have identical or varying widths and dimensions. The individual panels 609 are preferably designed to fit together and include means for attaching to each other. For example, each panel 609 may be secured to each other by various conventional means, e.g., via snaps, by being slid into place and secured via interlocking mechanisms, etc. The individual panels 609 are removable/attachable to each other as desired to adjust the width of the overall side panel 601 . A lower bar panel 611 may also be added, for example, along the lower portion of the fence between each post covering 503 . The lower bar panel 611 may be secured to the fence 200 via snaps, screws, bolts, etc.
[0035] In another embodiment, the side panel 601 having the cap 603 and the lower bar panel 611 attached thereon may be provided as a single side panel unit 613 for ease of installation (see FIG. 6E). The single side panel unit 613 may be mounted onto one or both sides of the fence 200 . In yet another embodiment, the single side panel unit 613 may be further combined with at least one post covering 503 to provide a combined panel and post unit 615 (see FIG. 6F). The combined panel post unit 615 may include one or two post coverings 503 . It is to be noted that the side panel 601 , whether or not it is combined with the cap 603 , the lower bar panel 611 or the post covering 503 , may be constructed in various designs (e.g., cross-panels 617 (see FIG. 6G), picket design, etc.) and/or further customized to include various graphics (e.g., as described above for the interior panel 104 ).
[0036] In an alternate embodiment, the combined panel and post unit 615 may be modified, e.g., to have a removable lower section 619 as well as a removable lower post covering 621 (see e.g., FIG. 6H). It is to be noted that either the lower section 619 and/or the lower post covering 621 may be removed or added as desired. Preferably, the post covering 503 is attached at at least one point on the upper portion of the fence post 404 (see e.g., FIG. 6C) via, e.g., post mount 501 , mounting pieces 505 or modified post mount 607 as described above, such that even if the lower post covering 621 is removed, the remaining portion of the post covering 503 is supported by and affixed to the fence post 404 (not shown).
[0037] In another embodiment as shown in FIG. 6I, extended post coverings 623 may be provided which extend upwards a desired height beyond the height of the fence 200 . An upper panel 621 may be added which fits between the extended post coverings 623 to extend the height of the fence 200 as desired. The upper panel 621 may be removably attached to the top of the cap 603 or to the top of the fence covering panel 100 , or be combined with the fence covering panel 100 as one unit. In addition, the extended post coverings 623 may optionally include attachment points (not shown) for securing each end of the upper panel 621 to the extended post coverings 623 .
[0038] In another embodiment as shown in FIG. 6J, a removable planter box 625 may be mounted between the extended posts 623 . The planter box 625 may be permanently affixed or integrally formed with the side panel 601 . It is to be noted that the planter box 625 may be affixed, for example, atop the cap 603 or directly atop the side panel 601 , and may further be secured to the extended posts 623 at each end. The extended posts 623 may further optionally include lamps 627 or other ornamental features attached, for example, at a top end.
[0039] Alternatively, the planter box 625 may be permanently/removably attached to the bottom end of the fence 200 between each post covering 503 (see e.g., FIG. 6 K). In this embodiment, the side panel 601 may include, for example, a removable panel 629 for providing pass-through of light through the fence 200 when the planter box 625 is used. It is to be noted that the side panel 601 may be comprised of openings, perforations, etc., in any configuration to also permit pass-through of light as desired.
[0040] A corner post covering 631 may be provided having slots 633 enabling the covering 631 to be slid into place over a fence corner post 635 (see FIG. 6L). Alternatively, an extended version of the corner post covering 631 may be provided and the slots 633 may serve as receiving points on at least two adjacent sides of the corner post covering 631 for permitting attachment of, for example, the upper panels 621 (see FIG. 6I). The slots 633 may comprise, e.g., openings sufficient for insertion of one end of the upper panel 621 and may include locking mechanisms to secure the upper panels 621 therein. Any other conventional means (e.g., snaps, bolts, etc.) for attachment of the upper panel 621 to the extended version of the corner post covering 631 may be contemplated.
[0041] [0041]FIGS. 7A-7C depict various embodiments of the present invention as adapted for fence gates. At a basic level, a gate side panel 701 , gate post coverings 703 and a gate cap 705 may be provided for covering a fence gate 700 . Alternatively, 701 , 703 and 705 may be provided as a combined single fence covering unit 707 (see FIG. 7B). It is to be noted that the fence post covering 503 which covers a fence post adjacent to the opening point of the fence gate 700 may be modified to include, e.g., a slot 709 or other means for receiving a gate locking hinge or other locking/closing mechanism on the fence gate 700 .
[0042] Having described preferred embodiments for fence covering systems (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the invention disclosed which are within the scope and spirit of the invention as outlined by the appended claims. Having thus described the invention with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims. | A fence covering system includes a frame configured and dimensioned to cover a portion of an existing fence. A panel is connected to the frame to provide a visual effect. A connector secures the frame on a portion of the fence, the connector providing an attachment position for the frame. | 4 |
FIELD OF THE INVENTION
[0001] The present invention relates to a process for the preparation of delmopinol, as well as to new intermediates useful in such a preparation process.
BACKGROUND ART
[0002] Delmopinol is the International Non-proprietary Name (INN) of 3-(4-propylheptyl)-4-morpholinethanol with CAS No. 79874-76-3. Delmopinol hydrochloride salt (CAS No 98092-92-3) is intended to be used in the treatment of gingivitis. The structure of delmopinol hydrochloride corresponds to the formula:
[0000]
[0003] Different processes for the preparation of delmopinol and its salts are known in the art. EP 038785-A describes several preparation processes of this compound. According to EP038785-A, delmopinol can be prepared by alkylation of a 3-substituted morpholine, by dialkylation of a primary amine with a substituted bis(haloethypether or a substituted diethyleneglycol disulfonate, by reduction of a morpholone, or by transformation of the N-substituent of the morpholine into a hydroxyethyl group. EP 0426826-A describes a process for the preparation of delmopinol which comprises a cycloaddition of a morpholine nitrone to obtain a morpholine-isoxazolidine or morpholine-isoxazoline, a reductive ring opening followed by transformation of functional groups present in the side chain, and finally alkylation of the nitrogen to yield delmopinol.
[0004] Despite the teaching of this prior art, research into new preparation processes of delmopinol is still an active field since the known processes are long and require the use of harsh hydrogenation conditions, some very toxic and/or flammable reagents or solvents which make their industrial exploitation difficult and expensive. Therefore, the provision of a new preparation process of delmopinol is highly desirable.
SUMMARY OF THE INVENTION
[0005] The inventors have found an efficient process for the preparation of delmopinol, as well as its pharmaceutically acceptable salts and/or solvates, which avoids the use of harsh hydrogenation conditions and extremely toxic and flammable reagents and solvents.
[0006] Thus, according to an aspect of the present invention, there is a process for the preparation of delmopinol of formula (I), or a pharmaceutically acceptable salt and/or a solvate thereof, including a hydrate,
[0000]
[0000] which comprises treating the compound of formula (II) either with a base in an appropriate solvent system, effecting both a deprotection of the amino ethanol and a cyclisation to yield the compound of formula (I) or, alternatively, treating the compound of formula (II) first with an acid in an appropriate solvent system at room temperature performing the deprotection of the amino ethanol, and than with a base effecting the cyclisation of the compound thus obtained to yield the compound of formula (I).
[0000]
[0007] In the previous formula (II), R1 and R2 are a radical, same or different, independently selected from the group consisting of H, (C1-C6) alkyl or, alternatively, R1 and R2 form, together with the carbon atom to which they are attached, a (C5-C6) cycloalkyl radical; and R3 is a radical selected from the group consisting of CF3, (C1-C4) alkyl, phenyl, and phenyl mono- or disubstituted by a radical selected from the group consisting of (C1 C4)-alkyl, halogen, and nitro.
[0008] The compound of formula (II) as defined above is previously prepared by reaction of a compound of formula (III) with a sulphonyl chloride of formula Cl-SO2-R3, where R1, R2, and R3 have the same meaning defined above for the compound of formula (II).
[0000]
[0009] The compound of formula (III) is previously prepared by a process which comprises reacting a compound of formula (IV) where R1 and R2 have the meaning defined above, with a compound of formula (V) in the presence of a base, and recovering the compound of formula (III) obtained by treating the reaction mixture with a mixture of water and at least one water-immiscible solvent at approximately 0-5° C., followed by separating the organic phase, which contains the product, from the aqueous phase. The compound of formula ((II), where R1 is H and R2 is a radical selected from the group consisting of H and (C1-C6) alkyl, can also be recovered in two steps through the formation of the compound of formula (VI) by treating the reaction mixture with an acid in the presence of water, followed by basification to isolate a compound of formula (VI) in neutral form. Subsequently, compound (VI) is subjected to a protection reaction characterised in that said compound (VI) is reacted with an aldehyde of formula R4CHO wherein R4 is selected from the group consisting of H and (C1-C6) alkyl to yield a compound of formula (III) wherein R1 is H and R2 is a radical selected from the group consisting of H and (C1-C6) alkyl.
[0000]
[0010] The compound of formula (V) is previously prepared by a process which comprises subjecting the compound of formula (VII) to an epoxidation reaction with an appropriate epoxidising agent.
[0000]
[0011] The compound of formula (VII) is previously prepared by subjecting the compound of formula (VIII) to an elimination reaction in the presence of an alkali metal alkoxide.
[0000]
[0012] Among the advantageous features of the processes of the present invention, the following can be mentioned: the process uses cheap and non-toxic starting materials, the reagents and solvents used are also of low toxicity, the process is carried out under mild reaction conditions, yields of every reaction step are high, several steps of the process can be carried out in one pot, and delmopinol is obtained with high purity.
[0013] Compounds of formula (II), (III), (V), (VI), (VII) and (VIII) are new. Thus, another aspect of the present invention is the provision of said new intermediate compounds as defined above.
DETAILED DESCRIPTION OF THE INVENTION
[0014] As described above, delmopinol can be obtained by subjecting a compound of formula (II) as defined above to a deprotection and to a cyclisation reaction in an appropriate solvent system. In a preferred embodiment, the compound of formula (II) is that where R3 is methyl. Preferably, the solvent system is a mixture of a (C6-C8)-aromatic hydrocarbon and water. Examples of suitable hydrocarbons are toluene and xylene.
[0015] The transformation can be carried out by treating the compound of formula (II) with a base preferably at a temperature between 50° C. and reflux temperature of the biphasic solvent system employed. Alternatively, the process can be accelerated by treatment of the compound of formula (II) with a dilute acid such as hydrochloric acid at room temperature, thereby effecting the deprotection of the amino ethanol, followed by reaction with a base at a temperature preferably between 50° C. and reflux temperature of the solvent system employed, thereby effecting the cyclisation. The base in both cases can be either an inorganic base or an organic base, for example sodium hydroxide or triethylamine.
[0016] The most adequate conditions for carrying out said processes vary depending on the parameters considered by an expert in the art, such as, for example, the concentration of the reaction mixture, temperature, the solvent used, and the like. These can be readily determined by said skilled person in the art with routine tests and with the help of the teachings of the examples given in this description.
[0017] Delmopinol obtained by the process of the present invention may be converted into pharmaceutically acceptable salts, and salts may be converted into the neutral form, by standard procedures described in the art. For instance, delmopinol can be converted into its hydrochloride salt by treating delmopinol with hydrochloric acid in an appropriate solvent. Suitable solvents to carry out the crystallisation of the salt obtained are, for instance, (C2 C10)-ethers such as methyl tert-butyl ether or di-n-butyl ether, (C6-C8)-aliphatic hydrocarbons such as heptane or hexane, aromatic hydrocarbons such as toluene or xylene, and (C2 C10)-esters such as ethyl acetate, and mixtures thereof.
[0018] The compound of formula (II) can be previously prepared from the corresponding alcohol by reaction with a sulphonyl chloride of formula Cl-SO2-R3, where R3 has the same meaning as defined above. In a preferred embodiment, the sulfonyl chloride is that where R3 is —CH3, C6H4CH3, —C6H5 and —CF3. In a more preferred embodiment, R3 is methyl.
[0019] Generally, the reaction is carried out in the presence of a tertiary amine in an appropriate inert solvent such as a (C6-C8)-aromatic hydrocarbon such as toluene or xylene, or a chlorine-containing solvent such as methylene chloride or 1,2 dichloroethane, at a temperature between approximately 0° C. and room temperature. Preferably, the reaction is carried out at low temperatures.
[0020] The preparation of the alcohol of formula (III) can be carried out by reacting a compound of formula (IV) as defined above with a compound of formula (V) in the presence of a base.
[0000]
[0021] Preferably, the base is selected from the group consisting of an alkali metal alkoxide such as potassium tert-butoxide and an alkali metal hydride such as lithium hydride or sodium hydride. Generally, the reaction is carried out at a temperature between approximately 50° C. and 90° C.
[0022] Best results are obtained when the reaction is carried out using an excess of the compound of formula (IV). Preferably the molar ratio between (IV) and (V) is at least 4:1. More preferably, the molar ratio is at least 5:1 resulting in a yield of at least 90%.
[0023] The compound of formula (III) obtained can be isolated by treating the reaction mixture with a mixture of water and at least one water-immiscible solvent such as toluene at 0-5° C., followed by separating the organic phase containing the product from the aqueous phase.
[0024] The compound of formula (III) where R1 is H and R2 is a radical selected from H and (C1-C6) alkyl can also be isolated from the compound of formula (VI). After the reaction between compound (IV) and (V), the reaction mixture is treated with an acid in the presence of water, followed by addition of a base, yielding a compound of formula (VI) which is isolated in neutral form.
[0000]
[0025] After isolation, for instance by elimination of the solvent, compound (VI) is subjected to a protection reaction characterised in that said compound (VI) is reacted with an aldehyde of formula R4CHO where R4 is selected from H and (C1-C6)-alkyl. Preferably, the aldehyde is selected from formaldehyde and propionaldehyde.
[0026] It is possible to carry out two or more of the steps of the process in one pot, as is illustrated in the Examples. Thus, the reaction between the compounds of formula (IV) and (V) to give the compound of formula (III), followed by the work-up based on the treatment of the reaction mixture with a mixture of water and at least one water-immiscible solvent at 0-5° C., the subsequent conversion into the compound of formula (II) and the final formation of the compound of formula (I), can be carried out in one pot without isolation of any intermediate. Likewise, the conversion of the compound of formula (VI) into the compound of formula (III), the subsequent conversion into the compound of formula (II) and the final formation of the compound of formula (I) can also be performed in one pot, without isolation of any intermediate.
[0027] The compound of formula (IV) can be prepared from diethanolamine by means of a protection reaction. The process comprises the reaction of diethanolamine with an aldehyde or a ketone. Examples of suitable aldehydes are formaldehyde and propionaldehyde. Examples of suitable ketones are acetone, cyclopentanone, cyclohexanone, methyl isobutylketone, and methyl ethylketone.
[0028] The compound of formula (V) can be prepared by epoxidation of 6-propylnon-1-ene (VII) with an epoxidising agent such as 3-chloroperoxybenzoic acid or peroxyacetic acid. The compound of formula (VII) is previously prepared by submitting the corresponding alkyl bromide (VIII) to an elimination reaction in the presence of an alkali metal alkoxide, preferably potassium tert-butoxide. Said compound (VIII) is previously obtained by bromination of the corresponding alcohol (IX).
[0000]
[0029] The bromination can be carried out with a brominating agent in the presence of a suitable solvent. It can also be carried out, for instance, with hydrobromic acid and sulfuric acid without any solvent, preferably at reflux temperature. The 6-propylnonan-1-ol (IX) is known and can be prepared as described in Examples from methods known in the art.
[0030] Throughout the description and claims the word “comprise” and variations of the word, such as “comprising”, are not intended to exclude other technical features, additives, components or steps. Additional objects, advantages and features of the invention will become apparent to those skilled in the art upon examination of the description or may be learned by practice of the invention.
[0031] The following examples are provided by way of illustration and are not intended to limit the scope of the present invention.
EXAMPLES
Example 1
Preparation of 6-propylnonane-1,6-diol
[0032] To a 250 mL two necked flask equipped with a condenser containing e-caprolactone (3,3 mL, 30 mmol) and anhydrous tetrahydrofuran (60 mL) under nitrogen atmosphere, was added at 0° C. dropwise propylmagnesium chloride (33 mL, 66 mmol, 2,2 eq., 2.0 M solution in diethyl ether). After addition, the reaction was stirred for 10 minutes at room temperature before heating to reflux for 2 hours. The reaction was monitored by thin layer chromatography. The reaction was cooled to 0° C. and saturated aqueous ammonium chloride (18 mL) was added followed, at room temperature, by hydrochloric acid (18 mL, 1 M aqueous). The organic phase was decanted and the aqueous phase extracted with dichloromethane (3×140 mL). The combined organic phases were washed with saturated aqueous sodium bicarbonate (100 mL) before drying over magnesium sulfate. Evaporation of the solvent gave the title compound (6,543 g, 96%) as a viscous yellow oil. 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,64 (t, J=6,7 Hz, 2H); 1,59 (tt, J=6,7 Hz, J=6,7 Hz, 2H); 1,46-1,24 (m, 15H); 0,88 (t, J=7,2 Hz, 6Hd). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 68,5; 64,2; 42,0(2C′); 39,8; 33,1; 26,8; 23,7; 17,1 (2C′); 14,5 (2C′). MS (IC+) m/z (%): 220,2 [M+18] (99); 202,2 (75); 203,3 [M+1] (30); 185,2 (100); 176,2 (60); 141,2 (25).
Example 2
Preparation of 6-propylnon-5-en-1-ol and (Z)- and (E)-6-propylnon-6-en-1-ol
[0033] To a 100 mL flask equipped with a Dean-Stark collector containing 6-propylnonane-1,6-diol (94% purity, 6,5 g, 30 mmol) in solution with 60 mL toluene, was added para-toluenesulfonic acid (285 mg, 1,5 mmol, 0,05 eq) before heating to reflux. The reaction was monitored by thin layer chromatography. After 2 hours the reaction is cooled to room temperature 160 mL toluene was added and the organic phase was washed with sodium bicarbonate (½sat. aq., 3×15 mL). The organic phase was dried with magnesium sulfate and evaporation gave of a mixture of the three title isomers (5,43 g, 98% yield) as a pale yellow oil. 1H NMR (CDCl3, 400 MHz) d?(ppm): 5,14-5,08 (m, 3H); 3,67-3,61 (m, 6H); 2,07-1,90 (m, 18H); 1,64-1,53 (m, 6H); 1,46-1,31 (m, 21H); 0,94 (t, J=7,4 Hz, 3H′); 0,93 (t, J=7,4 Hz, 3H); 0,88 (t, J=7,4 Hz, 6H); 0,87 (t, J=7,4 Hz, 3H); 0,86 (t, J=7,4 Hz, 3H′). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 139,6; 138,5 (2C); 126,8; 126,7; 63,0; 39.0; 36,8; 32,8; 32,7; 32,5; 32,1; 32,0; 29,9; 28,3; 28,0; 27,4; 26,2; 25,8; 25,5; 21,7; 21,6; 21,3; 21,0; 14,7; 14,2; 13,9. MS (IC+) m/z (%): 202,3 [M+18] (80); 185,3 [M+1] (100); 104,1 (59); 77,1 (50).
Example 3
Preparation of 6-propylnonan-1-ol
[0034] To a 100 mL flask containing a mixture of the three isomers obtained in Example 2 (5,43 g, 29,5 mmol) and absolute ethanol (70 mL) under nitrogen atmosphere, was added Pd/C 10% (543 mg, 10% mass). The vessel was purged with nitrogen followed by hydrogen with good stirring. The flask was equipped with a balloon containing hydrogen and the reaction was stirred at room temperature for 24 h. The reaction was monitored by 1H NMR. The reaction was purged with nitrogen and the catalyst was filtered off with a filter funnel (n o 3) containing Celite® and washed several times with absolute ethanol. Evaporation gave 6-propylnonan-1-ol (4,92 g, 90% yield) as a colorless oil. 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,64 (t, J=6,7 Hz, 2H); 1,58 (tt, J=6,7 Hz, J=6,7 Hz, 2H); 1,39-1,14 (m, 15H); 0,88 (t, J=6,8 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 63,0; 36,9; 36,0 (2C′); 33,6; 32,8; 26,5; 26,2; 19,8 (2C); 14,5 (2C).
Example 4
Preparation of 1-bromo-6-propylnonane
[0035] To a 50 mL flask containing 6-propylnonan-1-ol (4,92 g, 26,4 mmol) was added hydrobromic acid 48% (12 mL, 105,6 mmol, 4 eq.) and conc. sulfuric acid (1,4 mL, 26,4 mmol, 1 eq.) and the mixture was heated to reflux (95 ° C.) for 14 h. The reaction was cooled to room temperature before adding H2O (40 mL). The mixture was extracted with dichloromethane (3×120 mL) and the combined organic phases were washed with aqueous sodium bicarbonate (40 mL, 1 M). Drying over magnesium sulfate and evaporation gave 1-bromo-6-propylnonane (5,87 g, 89% yield) as a brown liquid. 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,40 (t, J=6,8 Hz, 2H); 1,86 (tt, J=6,8 Hz, J=6,8 Hz, 2H); 1,45-1,35 (m, 2H); 1,34-1,15 (m, 13H); 0,88 (t, J=6,8 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 36,9; 36,0 (2C); 34,0; 33,5; 33,9; 28,7; 25,8; 19,8 (2C); 14,5 (2C).
Example 5
Preparation of 6-propylnon-1-ene
[0036] To a 250 mL flask containing potassium tert-butoxide (13,27 g, 108,7 mmol, 4,6 eq.) under nitrogen atmosphere was added anhydrous tetrahydrofuran (100 mL) and via cannula 1-bromo-6-propylnonane (5,87 g, 23,54 mmol) in solution with anhydrous tetrahydrofuran (20 mL) was transferred at 0° C. The mixture was then stirred at room temperature for 2 h. Hydrochloric acid (230 mL, 1 M) was added slowly and the mixture was extracted with cyclohexane (300 mL+3×100 mL). The combined organic phase was washed with aqueous sodium bicarbonate (100 mL, 1 M) and dried over magnesium sulfate. The solvent was carefully evaporated under moderate vacuum (at room temperature because of the high volatility of the alkene) to give 3,3 g (84%) of 6-propylnon-1-ene as a brown liquid. 1H NMR (CDCl3, 400 MHz) d?(ppm): 5,82 (ddt, J=6,8 Hz, J=10,2 Hz, J=16,9 Hz, H); 5,00 (broad d, J=16,9 Hz, H); 4,93 (broad d, J=10,2 Hz, H); 2,02 (dt, J=6,8 Hz, J=6,8 Hz, 2H); 1,41-1,30 (m, 2H); 1,32-1,15 (m, 11H); 0,88 (t, J=7,1 Hz, 6H′). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 129,3; 114,1; 36,8; 36,1 (2C); 34,3; 33,2; 26,0; 19,8 (2C); 14,5 (2C ). MS (IE) m/z (%): 169,1 [M+] (25); 141,1 (30); 125,0 (57); 113,0 (40); 99,0 (44); 85,0 (67); 71,0 (73).
Example 6
Preparation of 2-(4-propyl-heptyl)-oxirane
[0037] To a 250 ml flask containing 6-propylnon-1-ene (4 g, 23,76 mmol, purified by distillation) and anhydrous dichloromethane (260 mL) under nitrogen atmosphere, was added at 0 ° C. meta-chloroperoxybenzoic acid (77%, 10,65 g, 47,53 mmol, 2 eq) and the reaction was stirred for 20 minutes at 0 ° C. before warming to room temperature. The disappearance of starting material is monitored by TLC. The reaction was evaporated almost to dryness and cyclohexane (260 ml) was added and the remaining solid in the flask was extracted several times with cyclohexane. The combined organic phases were then washed with saturated aqueous sodium bicarbonate (5×25 mL). After evaporation of the solvent, the crude was purified by column chromatography (eluent dichloromethane) to give the desired product (3,86 g, 88%) as a colourless oil.
[0038] To a solution of 6-propylnon-1-ene (16.35 g, 97.34 mmol) in toluene (90 ml) and aqueous sodium acetate (4.87 ml, 1 M, 4.87 mmol) at ambient temperature was added peroxyacetic acid (24.55 ml, 32 wt % in dilute acetic acid, 116.81 mmol) dropwise over 10 min. The mixture was heated to 60° C. and the reaction progress followed by gas chromatography (GC). After 5 h, GC indicated 3% remaining alkene and the mixture was left stirring at ambient temperature for 16 h, after which only 1% alkene remained (85.7% overall purity, containing 8.7% saturated hydrocarbon contaminant from alkene). On completion, the biphasic mixture was treated with aqueous sodium bisulfite (10%, 80 ml) and the organic phase was separated. The aqueous phase was extracted with toluene (2×40 ml) and the combined organic phases were washed with water (2×40 ml), dried over sodium sulfate, filtered and concentrated in vacuo to give a pale yellow oil (20.9 g, 117%). Purification by chromatography (silica, dichloromethane) gave 2-(4-propyl-heptyl)-oxirane (14.42 g, 81%) as a colourless oil. 0,42 Eluent (CH2Cl2); Rev.: Anisaldehyde; Colour: blue-green. 1H NMR (CDCl3, 400 MHz) d?(ppm): 2,94-2,87 (m, H); 2,74 (dd, J=3,9 Hz, J=4,9 Hz, H); 2,46 (dd, J=2,7 Hz, J=4,9 Hz, H); 1,55-1,47 (m, 2H); 1,49-1,36 (m, 2H); 1,36-1,17 (m, 11H); 0,88 (t, J=6,8 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d??(ppm): 52,4; 47,1; 36,9; 35,9 (2C); 33,4; 32,9; 23,1; 19,8 (2C); 14,5 (2C).
Example 7
Preparation of 2,2-dimethyl-3-(2-hydroxyethyl)-oxazolidine
[0039] To a 100 mL flask containing diethanolamine (19,2 mL, 200 mmol) was added acetone (29,4 mL, 400 mmol, 2 eq.) and potassium carbonate (pulverised and dried at 160° C., 27,6 g, 200 mmol, 1 eq.). The reaction was stirred at room temperature for one day. The mixture was filtered through a sinter funnel (no. 3) and the collected solid was washed with acetone. The filtrate and the washes were combined and the solvent evaporated. The 1H NMR indicated a conversion of 85%. Distillation at 125-132 ° C./20 mmHg of the crude reaction gave the title product (20,89 g, 72% yield) as a colourless oil. 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,93 (t, J=6,6 Hz, 2H); 3,62 (t, J=5,3 Hz, 2H); 2,96 (t, J=6,6 Hz, 2H); 2,65 (t, J=5,3 Hz, 2H); 1,23 (s, 6H). 13C NMR (CDCl3, 129,9 MHz) d??(ppm): 94,2; 63,5; 59,3; 50,8; 49,1; 23,3 (2C).
Example 8
Preparation of 2-(1-oxa-4-aza-spiro [4.5]dec-4-yl)-ethanol
[0040] To a 50 mL flask containing diethanolamine (9,7 mL, 100 mmol) was added cyclohexanone (10,4 mL, 100 mmol, 1 eq.) and potassium carbonate (pulverized and dried at 160° C., 13,8 g, 100 mmol, 1 eq.). The reaction was stirred at 80° C. for 12 h. The reaction was cooled to room temperature and diluted with dichloromethane before filtering off potassium carbonate. The crude mixture diluted in cyclohexane was washed with water at 0° C. Drying with sodium sulfate and evaporation afforded the title product (8,4 g, 45% yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,91 (t, J=6,7 Hz, 2H); 3,60 (m, 2H); 3,00 (t, J=6,7 Hz, 2H); 2,70 (t, J=5,3 Hz, 2H); 1,72-1,50 (m, 7H); 1,43-1,30 (m, 2H); 1,21-1,04 (m, 1H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 94,9; 63,2; 59,2; 50,3; 49,0; 32,6 (2C); 25,6; 23,3 (2C).
Example 9
Preparation of 2-oxazolidin-3-yl-ethanol
[0041] To a 250 mL flask containing paraformaldehyde (11,41 g, 380 mmol, 1 eq.) in toluene (76 mL), was added diethanolamine (36,5 mL, 380 mmol d=1,0955) diluted with isopropanol (76 mL) before heating to reflux with a Dean-Stark trap for 19 h. The reaction was cooled to room temperature and, after evaporation, 47,57 g of crude product was obtained. The crude obtained was purified by distillation with vacuum to give the title compound (38,33 g, 86% yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 4,32 (s, 2H); 3,78 (t, J=6,7 Hz, 2H); 3,64 (t, J=5,3 Hz, 2H); 3,00 (t, J=6,7 Hz, 2H); 2,73 (t, J=5,3 Hz, 2H).
Example 10
Preparation of 2-(2-ethyl-oxazolidin-3-yl)-ethanol
[0042] To a 250 mL flask containing diethanolamine (2,9 mL, 30 mmol d=1,0955) in dichloromethane (60 mL) under nitrogen atmosphere, was added potassium carbonate (8,3 g, 60 mmol, 2 eq.) before adding at 0° C. dropwise propionaldehyde (2,73 mL, 37,5 mmol, 1,25 eq.). The reaction was warmed to room temperature and stirred for 3 h. The potassium carbonate was filtered with a sinter funnel and washed several times with dichloromethane. After evaporation of the combined organic phases, 4,994 g of crude product was obtained. The product was purified by distillation under vacuum to give the title compound (3,87 g, 87% yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,93 (dd, J=4,3 Hz, J=6,4 Hz, H); 3,92-3,82 (m, 2H); 3,71-3,58 (m, 2H); 3,26 (ddd, J=5,5 Hz, J=6,5 Hz, J=12,2 Hz, H); 2,83 (ddd, J=4,9 Hz, J=8,2 Hz, J=12,7 Hz, H); 2,66 (dt, J=7,0 Hz, J=10,0 Hz, H); 2,55 (dt, J=3,9 Hz, J=12,2 Hz, H); 1,60 (ddq, J=4,3 Hz, J=7,4 Hz, J=14,1 Hz); 1,51 (ddq, J=6,4 Hz, J=7,4 Hz, J=14,1 Hz); 0,95 (t, J=7,4 Hz, 3H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 97,5; 64,1; 60,0; 55,1; 51.7; 26,8; 8,9.
Example 11
Preparation of 1-[2-(2-hydroxy-ethylamino)-ethoxyl]-6-propyl-nonan-2-ol
[0043] To a 10 mL Schlenk tube containing potassium tert-butoxide (125 mg, 1 mmol, 0,5 eq.) under nitrogen atmosphere, was added freshly distilled 2,2-dimethyl-3-(2-hydroxyethyl)-oxazolidine (1,4 mL, 10 mmol, d 1,035, 5 eq.) before heating at 75° C. until complete dissolution. To the solution was added slowly 2-(4-propyl-heptyl)-oxirane (0,43 mL, 2 mmol, d 0,856) over 1 h at 75° C. The reaction was stirred at 75° C. After 6 h, the reaction was cooled to room temperature before adding diethyl ether (40 mL). The organic phase was extracted with aqueous hydrochloric acid (1 M, 3×12 mL). Then, a solution of aqueous sodium hydroxide (25%) was added to bring the mixture to pH 14 before extracting it with diethyl ether (4×16 mL). The combined organic phases were dried over sodium sulfate and concentrated to afford the title compound (515 mg, 90% yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,83-3,74 (m, H); 3,67 (t, J=5,2 Hz, 2H); 3,67-3,56 (m, 2H); 3,52 (dd, J=2.7 Hz, J=9,9 Hz, H); 3,30 (dd, J=8,2 Hz, J=9,9 Hz, H); 3,05-2,96 (m, 2H+2H); 1,50-1,15 (m, 15H); 0,87 (t, J=7,0 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 75,9; 70,3; 70,2; 60,9; 51,1; 48,9; 36,9; 36,0 (2C); 33,7; 33,6; 22,7; 19,8 (2C); 14,5 (2C).
Example 12
Preparation of 1-[2-(2,2-dimethyl-oxazolidin-3-yl)-ethoxyl]-6-propyl)-nonan-2-ol
[0044] To a 250 mL flask containing sodium methoxide (1,35 g 25 mmol, 0,25 eq) under nitrogen atmosphere, was added freshly distilled 2,2-dimethyl-3-(2-hydroxyethyl)-oxazolidine (70,15 mL 500 mmol, d 1,035, 5 eq.) before heating at 50° C. until complete dissolution (20 min). The reaction was then connected to a vacuum line (3-4 mBar) for 90 min to remove the methanol formed in situ. To the solution was added slowly 2-(4-propyl-heptyl)-oxirane (21,53 mL 100 mmol, d 0,856) over 1 h at 75° C. The reaction was stirred overnight at 75° C. After 17 h, the reaction was cooled to room temperature before adding toluene (125 mL). To the mixture cooled to 0° C. was added water (100 mL, precooled to 0° C.) before stirring for 1 h at 0° C. The organic phase was recovered and the aqueous phase was extracted with toluene (2×35 mL, precooled to 0° C.). The combined organic phases were washed with 25 mL water (precooled to 0° C.) and partially evaporated (by 15% vol.) at 35° C. with vacuum (30 mBar) to effect azeotropic drying. The organic phase was diluted with toluene (32 mL) and was used directly in the next step. It was possible to isolate the product by evaporating the solvent on a rotavapor. 1H NMR (CDCl3, 400 MHz) d?(ppm): 3,91 (t, J=6,6 Hz, 2H); 3,81-3,73 (m, H); 3,67 (dt, J=5,6 Hz, J=10,2 Hz, H); 3,61 (dt, J=5,6 Hz, J=10,2 Hz, H); 3,56 (dd, J=2,7 Hz, J=10,2 Hz, H); 3,30 (dd, J=8,2 Hz, J=10,2 Hz, H); 3,05-2,96 (m, 2H); 2,67 (t, J=5,6 Hz, 2H4); 1,50-1,15 (m, 21H); 0,87 (t, J=7,0 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 94,5; 76,0; 70,7; 70,5 ; 63,5; 50,4; 49,5; 36,9; 36,0 (2C); 33,7; 33,5; 23,1; 23,0; 22,7; 19,7 (2C); 14,5(2C).
Example 13
Preparation of 1-(2-oxazolidin-3-yl-ethoxy)-6-propyl-nonan-2-ol
[0045] To a 10 mL flask containing paraformaldehyde (52 mg, 1,73 mmol, 1 eq.) in toluene (1 mL), was added 1-[2-(2-hydroxy-ethylamino)-ethoxy]-6-propyl-nonan-2-ol (500 mg 1,73 mmol) diluted with isopropanol (1mL) before heating to reflux with a Dean-Stark trap for 17 h. The reaction was cooled to room temperature and, after evaporation, 520 mg of a mixture of products was obtained with the title compound as the major component (100% crude yield). 1H NMR (CDCl3, 400 MHz) d?(ppm); 4,33 (s, 2H); 3,78 (t, J= 6,8 Hz, 2H); 3,83-3,74 (m, H); 3,70-3,57 (m, 2H); 3,55 (dd, J=2,7 Hz, J=10,0 Hz, H); 3,29 (dd, J=8,2 Hz, J=10,0 Hz, H); 3,02 (t, J=6,8 Hz, 2H); 2,81-2,74 (m, 2H); 1,50-1,12 (m, 15H); 0,87 (t, J=7,0 Hz, 6H′). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 87,0; 76,0; 70,5; 70,3; 63,3; 54,3; 52,7; 36,9; 36,0 (2C); 33,7; 33,5; 22,7; 19,8 (2C); 14,5 (2C)
Example 14
Preparation of 1-[2-(2-ethyl-oxazolidin-3-yl)-ethoxy]-6-propyl-nonan-2-ol
[0046] To a 10 mL flask containing 1-[2-(2-hydroxy-ethylamino)-ethoxy]-6-propyl-nonan-2-ol (510 mg, 1,76 mmol, 1 eq.) in toluene (3 mL) was added dropwise at room temperature propionaldehyde (0,14 mL 1,85 mmol, 1,05 eq., d=0,798) before heating to reflux with a Dean-Stark trap for 2h. The reaction was cooled to room temperature and concentrated to afford the title compound as 2 stereoisomers (50:50) (580 mg, 100% yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 4,09-4,03 (m, H); 3,92-3,81 (m, 2H); 3,81-3,73 (m, H); 3,73-3,50 (m, 2H+2H); 3,35-3,21 (m, 2H); 2,92-2,74 (m, 2H); 2,72-2,63 (m, H); 2,62-2,52 (m, H); 1,69-1,14 (m, 15H+2H); 0,96 (m, 3H); 0,87 (t, J=7,0 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 98,0; 97,9; 78,1; 75,7; 70,6 (2C); 70,2 (2C); 64,2 (2C); 53,2; 53,1; 52,6 (2C); 36,9 (2C); 36,0 (2C+2C); 33,7 (2C); 33,6; 33,5; 26,9; 26,8; 22,7 (2C); 19,8 (2C+2C); 14,5 (2C+2C); 9,2 (2C).
Example 15
Preparation of Methanesulfonic Acid 1-[2-(2,2-dimethyl-oxazolidin-3-yl)-ethoxymethyl]-5-propyl)-octyl ester
[0047] To a 500 mL flask containing the crude solution of 1-[2-(2,2-dimethyl-oxazolidin-3-yl)-ethoxy]-6-propyl)-nonan-2-ol was added at 0° C. triethylamine (distilled over calcium hydride and stored over molecular sieves 3Å, 33,6 mL, 240 mmol, 2,4 eq.) and methanesulfonyl chloride (9,29 mL 120 mmol, 1,2 eq.). The reaction was stirred at 0° C. and monitored by TLC. After 90 min, TLC indicated complete conversion and the reaction mixture was directly used for the next step.
[0048] The isolation of the title compound (1.8 mmol scale) could be carried out by evaporating the solvent, diluting the residue with dichloromethane (15 mL), and washing the organic phase with water (3×3mL) followed by saturated aqueous sodium chloride (4mL). Drying over sodium sulfate and evaporation furnished the title compound (586 mg, 80% Yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 4,83-4,76 (m, H7); 3,89 (t, J=6,8 Hz, 2H); 3,69-3,52 (m, 2H+2H); 3,09 (s, 3H); 3,04-2,94 (m, 2H); 2,70-2,60 (m, 2H); 1,72-1,54 (m, 2H); 1,47-1,10 (m, 19H); 0, 88 (t, J=6,8 Hz, 6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 94,7; 82,7; 72,9; 71,2; 63,8; 50,7; 49,1; 38,9; 37,0; 36,1 (2C); 33,7; 32,4; 23,4; 23,1; 22,4; 19,9 (2C); 14,7 (2C).
Example 16
Preparation of Methanesulfonic Acid 1-[2-(2-ethyl-oxazolidin-3-yl)-ethoxymethyl]-5-propyl-octyl ester
[0049] To a 1O mL flask containing the crude solution of 1-[2-(2-ethyl-oxazolidin-3-yl)-ethoxyl-]6-propyl-nonan-2-ol (1,71 mmol) in toluene (3,5 mL) was added at 0° C. triethylamine (distilled over CaH2 and stored over molecular sieves 3Å, 575 μL, 4,1 mmol, 2,4 eq.) and methanesulfonyl chloride (158 μL, 2 mmol. 1,2 eq.). The reaction was stirred at 0° C. and monitored by TLC. After 60 min, TLC indicated complete conversion and the reaction mixture was directly used for the next step.
[0050] The isolation of the title compound was carried out by evaporating the solvent, diluting the residue with dichloromethane (15 mL), and washing the organic phase with water (3×3mL) followed by saturated aqueous sodium chloride (4mL). Drying over sodium sulfate and evaporation furnished the title compound as 2 stereoisomers (524 mg, 75%yield). 1H NMR (CDCl3, 400 MHz) d?(ppm): 4,83-4,73 (m, 2×H); 4,06-3,96 (m, 2×H); 3,90-3,80 (dd, J=5,9 Hz, J=7,2 Hz, 2×2H); 3,70-3,54 (m, 2×2H5+2×2H); 3,31-3,22 (m, 2H); 3,08 (s, 2×3H); 2,88-2,77 (m, 2H); 2,70-2,59 (m, 2H); 2,59-2,48 (m, 2H); 1,74-1,52 (m, 2×2H8); 1,52-1,14 (m, 2×15H); 0,94 (t, J=7,4 Hz, 2×3H); 0,88 (t, J=6,8 Hz, 2×6H). 13C NMR (CDCl3, 129,9 MHz) d?(ppm): 94,80; 94,75; 82,38; 82,29; 72,6 (2C); 70,7 (2C); 64,23; 64,19; 52,71; 52,66; 52,58; 52,57; 38,55; 38,54; 36,7 (2C); 35,84 (2C′); 35,82 (2C); 33,4(2C); 32,1 (2C); 26,81; 26,77; 22,1 (2C); 19,7 (4C); 14,4 (4C); 905; 9,03.
Example 17
Preparation of Delmopinol
[0051] To a 500 mL flask containing the crude mesylation reaction obtained in Example 15, was added deionised water (65 mL) before heating to reflux (approx. 95° C.), After 17 h, the reaction was cooled to room temperature and the aqueous phase was separated from the organic phase. The aqueous phase was extracted with toluene (25 mL). The combined organic phases were evaporated to a volume of 200 mL (approx. 5 vol.) before adding water (120 mL). To the well stirred mixture, was added sufficient concentrated sulfuric acid to bring the mixture to pH 1. The two phases were separated and the aqueous phase was washed with toluene (2×20 mL). An organic solvent (120 mL of toluene, xylene or di-n-butyl ether) was added to the aqueous phase, followed, with good stirring, by a solution of aqueous sodium hydroxide (25%) to bring the mixture to pH 14. The mixture was heated at 60° C. for 10 min before separating the phases. The aqueous phase was extracted with 20 mL of the corresponding organic solvent using the same procedure as before (60° C. for 10 min before separating the phases). The combined organic phases were washed with aqueous ammonia (0,5%, 2×15 mL). After each wash, the mixture was heated to 60° C. for 10 min. The organic phase was half evaporated to remove traces of ammonia. Active carbon (5 wt %, Norit SX Plus) was added, and the mixture was heated to 50° C. for 20 min. The active carbon was filtered off and the solvent was evaporated to give crude delmopinol (24 g, 89% crude yield) as a yellow oil.
Example 18
Preparation of Delmopinol
[0052] To a 25 mL flask containing the crude mesylation reaction obtained in Example 16 (1,78 mmol product), was added deionised water (3,5 mL) before heating to reflux (approx. 95° C.). After 17 h, the reaction was cooled to room temperature and the aqueous phase was separated from the organic phase. The aqueous phase was extracted twice with toluene (2×7 mL). The combined organic phases were washed with aqueous sodium chloride (3×9 mL, 20% saturated). After drying over sodium sulfate the purification was carried out by column chromatography (eluent methanol/dichloromethane: 0/100 to 5/95) to furnish delmopinol (337 mg, 70% yield).1H NMR (CDCl3, 400 MHz) d?(ppm): 3,79-3,70 (m, 2H); 3,69-3,60 (m, 2H); 3,59 (m, 1H); 3,45 (dd, J=7,0 Hz, J=11,3 Hz, H); 2,98-2,89 (m, 1H); 2,88-2,78 (m, 1H); 2,45-2,30 (m, 3H); 1,56-1,36 (m, 2H); 1,36-1,11 (m, 13H); 0,88 (t, J=7,0 Hz, 6H). 13C NMR (CDCl3, 400 MHz) d?(ppm): 70,5; 67,1; 59,8; 57,8; 54,6; 49,8; 36,9; 36,0 (C); 35,9 (C); 34,0; 27,3; 23,3; 19,8 (C); 19,7 (C); 14,5 (2C).
Example 19
Preparation of Delmopinol Hydrochloride
[0053] To a 25 mL flask containing the crude delmopinol in solution with toluene or xylene coming from the last work-up, was added hydrochloric acid (37%, 1 eq.) before distilling a part of the solvent to eliminate the water. Toluene or xylene was added at 60° C. to obtain a homogeneous organic phase (to obtain 4 mL/g delmopinol in total). Then, heptane (5 mL/g delmopinol) or di-n-butyl ether (4 mL/g delmopinol) was added before cooling the mixture to room temperature. After seeding, the mixture was stirred 1 h at room temperature and 3 h at 0° C. The solid was filtered with a sinter funnel and washed at 0° C. with the same solution used for the crystallisation (1 mL/g delmopinol). Drying under vacuum gave delmopinol hydrochloride (50-70% yield) as a white powder.
Example 20
Preparation of Delmopinol Hydrochloride
[0054] To a 25 mL flask containing 2 g crude delmopinol in solution with toluene, xylene or dibutyl ether coming from the last work-up, was added hydrochloric acid (37%, 1 eq.) before distilling partially or to dryness (if toluene or xylene) to eliminate water. Di-n-butyl ether (to obtain 5 mL/g delmopinol in total) was added to delmopinol hydrochloride before heating at 60° C. Then a polar solvent (ethyl acetate 1.3 mL/g delmopinol) was added dropwise to the solution to effect complete dissolution, and the mixture was cooled to room temperature before seeding and stirring 1 h at room temperature and 2 h at 0° C. The solid was filtered with a sinter funnel and was washed at 0° C. with the same solution used for the crystallisation (1 mL/g delmopinol). Drying under vacuum gave delmopinol hydrochloride (1,51 g, 67% yield, 60% overall yield from (V)) as a white powder. 1H NMR (CDCl3, 400 MHz) d??(ppm): 11,98-11,69 (m, 1H); 4,42-4,29 (m, 1,3H); 4,14-3,91 (m, 4,5H); 3,89-3,73 (m, 1,3H); 3,64-3,55 (m, 1H); 3,48-3,37 (m, 1H); 3,24-2,89 (m, 3H); 2,01-1,78 (m, 2H); 1,61-1,12 (m, 13H); 0,88 (t, J=7,0 Hz, 6H).13C NMR (CDCl3, 400 MHz)) d?(ppm): 67,7 (C-O); 65,1 (C-N min.); 63,6 (C-O); 63,2 (C maj.); 59,9 (C min.); 57,1 (C-N maj.); 55,9 (C); 53,2 (C-N maj.); 48,3 (C-N min.); 36,6 (C); 35,6 (C); 35,5 (C); 33,3; 27,1; 22,9; 19,5 (2C′) ; 14,3 (2C) | It comprises a process for the production of delmopinol or a pharmaceutically acceptable salt and/or a solvate thereof, by subjecting the compound of formula (II) where R1 and R2 are the same or different, independently selected from the group consisting of H, (C1-C6) alkyl or, alternatively, R1 and R2 form, together with the carbon atom to which they are attached, a (C5-C6) cycloalkyl radical; and R3 is a radical selected from the group consisting of CF3, (C1-C4) alkyl, phenyl, and phenyl mono- or disubstituted by a radical selected from the group consisting of (C1-C4)-alkyl, halogen and nitro to a deprotection and cyclisation reaction. The process is useful to prepare delmopinol or its salts on an industrial scale. The compound of formula (II) is new and also forms part of the present invention, as well as its preparation process and other new intermediates of said preparation process. | 2 |
BACKGROUND OF THE INVENTION
It is known that certain materials will change their color and their ability to transfer light under the influence of an electrical field. This property is widely used in liquid crystal display electronic devices such as watches. However, the material is relatively expensive and has not been generally applied in greenhouses or other buildings. It has also been suggested that certain chemicals will reversibly change their state and their light transmission properties with changes in temperature.
A series of patents has issued which indicate that certain specific organic chemicals will reversibly change their state and their light transmission properties with changes in temperature. These patents indicate that specific organic polymers will, at a "cloud point", go into, or out of, solution when their temperature is raised. At their cloud point, when they are deposited out of the solution, the color or light transmission will change. However, commercially these materials have not been incorporated in flexible plastic resin films.
In U.S. Pat. Nos. 3,953,110 and 4,307,942 to Day Charoudi, a temperature responsive visible radiation control, polyvinylmethylether (PVME) is ". . . incorporated into a gel matrix by crosslinking or applied as an emulsion in a paint"(U.S. pat. No. 3,953,110, column 4, lines 54-56). Charoudi uses PVME and "cross linked hydroxyethyl methacrylate-hydroxyethyl acrylate copolymer" as the "gel or matrix" (U.S. Pat. No. 4,307,942, column 3, lines 44-53). In U.S. Pat. No. 4,260,225 to Walles a cloud-point polymer, i.e., having inverse solubility with a temperature rise, based on N-vinyl-5-methyl-2-oxazolidinone (PVO-M).
In a greenhouse, when the temperature rises past a certain point, the plants may be damaged. It would be useful if the greenhouse wall could change its light transmission property at a predetermined temperature point to avoid an excessive amount of sunlight from entering the greenhouse and raising its temperature. Similarly, in other buildings, if the windows or walls could reflect more sunlight, at a predetermined rise in ambient temperature, it may be possible to reduce the air conditioning load, control the sunlight entering the building or, in other ways, improve the building's functions.
OBJECTIVES AND FEATURES OF THE INVENTION
It is a feature of the present invention to provide a relatively rigid plastic structure sheet having parallel and connected hollow cells which sheet will reversibly alter its light transmission properties when subjected to changes in ambient temperature.
It is a further objective of the present invention to provide such a composite flexible film material and a plastic structure, both of which will be relatively longer lived and will not dry out or crack or otherwise fail in usage for at least one year under room temperature conditions.
It is a further objective of the present invention to provide such a composite film material and plastic structure, both of which will be relatively low in cost and light in weight as compared to glass sheets, so that it may be used in greenhouses, domes and other architectural uses in which the cost or weight of glass sheets would make their use impractical.
It is a further objective of the present invention to provide such a composite film material and plastic structure, both of which will be relatively stable over the period of its use and will not permit sagging, i.e., collection of the fluid material in spots, or gapping, i.e., the absence of the fluid material from other spots.
It is a further objective of the present invention to provide a relatively rigid plastic structure, which will reversibly change its light reflective property at a predetermined temperature and which will give a higher "black-out", i.e., the prevention of light being transmitted.
It is a feature of the present invention, in one embodiment, to provide a semi-rigid plastic resin channel sheet structure which has a top sheet, a bottom sheet and a series of parallel side walls forming elongated enclosed cells. The cells contain a gel including polyvinyl methyl ether (PVME) and one or more non-ionic surfactants to provide a wide range of temperature control, depending upon the temperature control additives. The temperature control is primarily determined by the choice of non-ionic surfactant by varying the ratio of non-ionic surfactants to PVME and by varying the concentration of both the PVME and the non-ionic surfactants. The gel also contains two gelling agents; the first provides a polymer matrix and the second, which is a hydroscopic polymer, binds the water within the gel and helps prevent evaporation.
It is a feature of the present invention, in one embodiment, to provide a method of forming a heat-responsive sheet. The sheet, after formation, is transparent to light when cool and reflective when it is heated. The method comprises, in order, the steps of coating one side of a transparent plastic resin film with a liquid composition which contains bentonite and a water solution of polyvinyl methyl ether having a predetermined cloud point, preferably a plastic resin film.
The next steps are to dry the coated film, transport it in its dried state and, at the location of assembly, add water to wet the coating. The wetted coated surface is then applied to a transparent sheet to form a sandwich. Preferably both the plastic resin films are low water vapor permeability films. The coating, when applied, may also contain salts to lower the cloud point.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objectives and features of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.
In the drawings:
FIG. 1 is an enlarged cross-sectional view of the composite film material of the first embodiment of the present invention;
FIG. 2 is a view of the material of FIG. 1 installed in face-to-face contact with a heat-responsive sheet;
FIG. 3 is a cross-sectional and perspective view of a second embodiment of the present invention employing a single layer of a channel sheet;
FIG. 4 is a cross-sectional and perspective view of a third embodiment utilizing two layers of channel sheets; and
FIG. 5 is a cross-sectional and perspective view of a fourth embodiment utilizing a single honeycomb channel sheet.
DETAILED DESCRIPTION OF THE INVENTION
The present invention utilizes a material which is responsive to changes in ambient temperature. The material has a "cloud point" at which the color of the material changes at a predetermined temperature. The preferred material is poly(vinyl methyl ether), which is a linear homopolymer methyl vinyl ether (hereinafter PVME). The PVME material is available as a resin under the trademark Gantrez M polymer from GAF Corporation (New York City). More specifically, the preferred material is GAF Gantrez M154, which is a solution of poly(vinyl methyl ether) in water at a 50% solids level. An alternative PVME polymer is "Lutonal" M40 from BASF (Wyandotte, Michigan).
The "cloud point" indicates the temperature at which the material will change its color, due to precipitation out of solution. Generally, materials, as they are heated, become more soluble in solution and, as the material is cooled, may at a certain critical temperature precipitate from the solution. However, with PVME the reaction to temperature change is opposite. It is in solution at the lower temperature and precipitates out at higher temperatures. At lower temperatures the PVME material is almost perfectly transparent. However, at higher temperatures, after the cloud point is reached, the material becomes white and will reflect light. Similarly, certain non-ionic surfactants also exhibit cloud point behavior. In addition, non-ionic surfactants, as a chemical group, could be used by themselves, without PVME, to give a white-out or haze control.
Preferably, a special composition is mixed which consists of the PVME, which is poly(vinyl methyl ether), Bentonite clay and other materials in the following proportions:
______________________________________ Part by Volume______________________________________Poly(vinyl methyl ether) 211 ccM154 - GAFWater 211 ccSH, a surfactant wetting agent 4 ccfrom DuPontMethyl alcohol 36 ccGlycolic acid 3 ccBentonite (EW Bentone) 11 cc______________________________________
Bentonite is a soft, porous, moisture-absorbing clayey mineral. It essentially contains montmorillonite (RMg Al 5 Si 12 O 30 (OH) 6 . n H 2 O, where R represents exchangeable bases, i.e., hydrous aluminum silicate. The preferred bentonite is "EW Bentone" available from NL Industries (New Jersey) and is in the range 2-8% (vol.).
This mixture is then applied on one side of a transparent plastic resin film, for example, by spraying or rolling. The mixture at that point has the consistency of a thick paste. The mixture is then dried, forming a thin tan-colored coating on the plastic film. The film is now ready for shipment and may be rolled onto itself to form a roll. The dried coating is not tacky and does not stick to the material onto which it is rolled. Consequently, an intermediate separation sheet is not required. The coated film is shipped to the field in its dried and rolled status.
In the field the coating is reconstituted by the addition of water which is preferably added by spraying the coating with a fine water spray. As shown in FIG. 1, the film 10, with its wetted coating 11, is then applied to a transparent sheet 12 which is preferably a rigid or flexible sheet of plastic. As shown in FIG. 2, the plastic sheet 12 to which it is applied may also be a plastic resin film. Consequently, the wetted cloud point mixture 10 is sandwiched between two layers of plastic resin film. Preferably both the films 10,12 are of low-water-pressure permeability, i.e., a moisture barrier. The preferred films are Mylar (TM of Dow Chemical Corp.) and Tedlar (TM of DuPont) and Saran (TM of Dow Chemical Corp. for a vinylidene chloride-vinyl chloride copolymer having copolymer crystals). The preferred thickness of the plastic resin film is 2 mils, although film in the range 1-10 mils may be used.
In the second embodiment of the present invention, as shown in FIG. 3, material which is responsive to change in ambient temperature is captured in a gel which is held within channels in a relatively structural sheet. As shown in FIG. 3, the sheet member 20 consists of a plurality of elongated cells 21a through 21e. Each cell forms an internal channel and has four walls, so that its cross-sectional shape is a square. Preferably the entire structural sheet 20 is formed, for example, by plastic extrusion from a clear, semi-rigid plastic such as an acrylic polymer or polycarbonate, polyacrylate or co-extrusions of materials having complementary physical characteristics, i.e., polysulfone and polyacrylate; the first would protect the second from chemical attack at temperatures about 60° C. The second would act as the UV shield and structural container.
The material within the cells is a special cloud-point mixture which utilizes two gelling agents. The first preferred gelling agent is "Carbopol 940" (TM of B.F. Goodrich), which is a high molecular weight carboxy vinyl polymer. It forms a polymer matrix. The second preferred gelling agent is a hydroscopic polymer, to retain the water in the polymer matrix. A suitable second gelling agent is "Carbopol 910" (TM of B.F. Goodrich).
The cloud-point mixture also contains a non-ionic surfactant. The use of a suitable non-ionic surfactant, in tests, has provided a "black-out", i.e., non-transmittal of light, of over 99% when the cloud-point is reached. Alternatively, by placing the temperature at the cloud-point a partial effect is obtained and the sheet appears hazy, i.e., between white and clear. Also, the use of non-ionic surfactants permits a wide range of temperature control, at least in the temperature range 25°-40° C. The preferred non-ionic surfactants are (i) alkoxylates of linear fatty alcohols; (ii) nonylphenoxy poly (ethyleneoxy) ethanols; and (iii) octylphenoxy poly (ethyleneoxy) ethanols. For example, suitable non-ionic surfactants are LF 600 and LF 711, both available from BASF.
A neutralizer-base, preferably PLURIOL-Q, performs the following functions: (i) it aids in cross-linking the polymers; (ii) it neutralizes the polymer, i.e., maintains a desired pH; and (iii) it helps protect the system against metal-ion contamination. The system also preferably contains a suitable UV inhibitor and antioxidant such as Goodrite 3114 and EDTA (ethylene diamine tetra acetic acid) to help protect against metal ion contamination.
The formula given is by way of an example and does not imply a limitation or restriction to this formula only.
The preferred formula for the cloud-point mixture, for an instantaneous response, is:
______________________________________Non-ionic surfactant BASF-LF 600 5% by weight BASF-LF 711 5% by weightPVME M40 6-8% in 50% water solution - by weightNeutralizer PLURIOL-Q 0.5% by weightGelling agent Goodrich 940 0.3% by weightHydroscopic polymer Goodrich 910 0.05% by weightAntioxidant Goodrite 3114 50 ppmAnti-metal ion EDTA 20-30 ppmThe remainder isdistilled water______________________________________
The structural sheet 20 may be used, for example, as the well of a greenhouse. In one embodiment, the structure sheet 20 has applied to it a thin flexible sheet 23, of 2-6 mils in thickness, which is electrically resistive and produces heat when an electrical charge is applied. The sheet 23 is transparent, such as a polyester film, and may have a thin coating of electrically responsive material, preferably indium tin oxide, applied on its surface. When an electrical charge is applied to the sheet 23, its temperature rises. The rise in temperature of the sheet 23 will cause a color change in the structure 20, provided that the rise in temperature of the sheet 23 is sufficient to reach the cloud point of the material within the cells. Alternatively, heat may be obtained from electricity, by screenprinting an electro-conductive ink having a certain resistance, on a top or bottom surface of the sheet 20. The conductive layer may also provide an effective low emissivity layer which reflects infra-red radiation, at night, to help retain heat within a structure. Alternatively, such a low emissivity layer may be used without being used for electrical heating.
An alternative structure is shown in FIG. 4. In this embodiment the cellular structure 30 comprises a first layer 31, which is the same as the cellular structure 20 of FIG. 3. A second structure 32 is connected to the first cellular structure 31. However, the vertically oriented ribs 33a through 33e of the first layer 31 are staggered, i.e., offset, relative to the ribs 34a through 34e of the underlying second cellular structure 32. In this way, any light which may be transmitted by the ribs is not transmitted through the entire structure as each of the ribs is applied with the center of the temperature responsive field material filling the cell aligned with that rib.
Alternatively, and as shown in FIG. 3 by the dark band 35, the ribs at their ends may be painted with a dark, preferably black, band so as to prevent light transmission through the cellular structure. The black bands prevent light transmission through the transparent ribs (side walls).
A similar structure to that of FIG. 4 is shown in FIG. 5. However, in this embodiment the cellular structure 40 is formed as a single unit preferably by means of plastic extrusion. In this case each rib 41a through 41e is centered on a corresponding cell 42a through 42e. This arrangement prevents light transmission, through the vertically aligned ribs 41a through 41e, from being transmitted through the structure 40. In this embodiment a single horizontal wall 43 separates the top row of cells 44 from the bottom row of cells 45.
The elongated cells of the embodiments in FIGS. 3-5 are closed and sealed at both of the ends of each of the cells. Such sealing prevents loss of water from the gel.
Alternatively, the cells may be sealed at their ends but interconnected by internal holes 45 through their ribs 41a-41e and 42a-42e, see FIG. 5. A drip mechanism 47, which may be a wick connected to a water supply, slowly adds water to the structure 40 to prevent drying of the gel. Such drying may occur due to water vapor loss through the exterior walls (top wall 48 and bottom wall 49).
In an alternative embodiment the side walls - ribs 21a-21e (FIG. 3) are formed of an opaque plastic resin to prevent light transmittal through the sheet.
Preferably the gel is relatively viscous, at least as hard as a gelatin product and preferably as viscous as soft putty.
The gelling of the cloud-point mixture is highly advantageous. It has been found, particularly in vertically aligned structures, that a cloud-point material in a liquid form will tend to migrate, over repeated cycles, and leave gaps. The gaps, instead of turning white with increased temperature, remain transparent. The gel prevents such migration, prevents gaps and maintains the mixture homogeneous.
The gel also prevents or slows-up the loss of water and thereby extends the life of the product. A loss of water through water vapor transmission through the cell walls would cause the cloud point mixture to become dried out and fail.
It has been found that the gel, to be most effective, should be formed into a plurality of layers of cells, preferably three layers. Tests have shown that with a single layer 9 mm thick, light transmittance of 80% below the cloud point (clear) and 2% light transmittance above the cloud point (white and opaque). In contrast, with three layers superimposed, each of 3mm (total thickness 9 pmm) the light transmittance was 55% clear and 0.2% opaque.
Another advantage of the present invention is that it provides a fire retardant property to the structure. The gel is preferably water-based and so helps prevent the plastic cell structure from spreading fire. | In greenhouses and other stuctures an excessive amount of sunlight on a hot day may cause overheating or may cause uneven lighting. A sheet is provided which is normally transparent but which becomes white and light-reflective at a predetermined temperature to help keep the structure cooled or help keep its lighting at a constant level. This color is reversible so that the sheet becomes transparent when the temperature falls. In one embodiment, the sheet consists of a unitary transparent plastic resin structure formed with elongated cells which are filled with a thick and viscous gel containing poly (vinyl methyl ether) or other suitable "cloud point" material. The gel helps prevent loss of water through the cell walls and prevents gaps which may occur from migration over repeated cycles of precipitation of the cloud point material, i.e., it helps keep the mixture homogeneous. In another embodiment the sheet comprises a plastic resin film which is coated with a liquid mixture including bentonite and a water solution of poly (vinyl methyl ether) and the mixture is dried and later re-wetted at the assembly site. | 8 |
CLAIM OF PRIORITY
[0001] This is a continuation in part application and claims priority to U.S. Utility application Ser. No. 11/561,191 titled “POLYMER OBJECT OPTICAL FABRICATION PROCESS” filed on Nov. 17, 2006.
FIELD OF TECHNOLOGY
[0002] This invention relates, generally, to microstereolithography. More particularly, it relates to a non-degenerate two-photon approach to projection microstereolithography.
BACKGROUND
[0003] Microstereolithography enables the manufacturing of small and complex three-dimensional components from plastic materials. One-photon polymerization is a process that causes a photo-initiator monomer concentration to induce a photochemical reaction, which in turn causes the concentration to cross-link and solidify.
[0004] The process is the basis for most commercially available stereolithography systems. Two-photon polymerization is a technique for the fabrication of three dimensional micron and sub-micron structures. A beam of ultra fast infrared laser is focused into a container holding a photo-sensitive material to initiate the polymerization process by non-linear absorption within the focal volume. By focusing the laser in three dimensions and moving the laser through the resin, a three dimensional structure can be fabricated. Two-photon microstereolithography enables three dimensional processing as well as high complexity micro-fabrication.
[0005] Researchers have demonstrated experimental two-photon micro/nano stereolithography but have not incorporated projection technology into the two-photon fabrication process and have not combined non-degenerate two-photon photopolymerization based on intersecting femtosecond pulsed projected images with picosecond pulsed laser light sheet at the focal plane. Existing two-photon stereolithography techniques enable unlimited complexity in the part geometries that can be fabricated by polymerizing a single focal volume voxel inside the bulk volume of photopolymer via the two-photon absorption process. However, these systems are limited in the volume that can be fabricated in a timely manner due to the point-by-point fabrication approach.
[0006] These systems also require ultra-precision control of translation or minor steering systems to generate parts of adequate resolution at the micro scale. The trend of everincreasing two-photon absorbing cross-sections of photoinitiators explicitly tailored for two-photon processes in recent years suggests that the speed of the scanning minor systems will also present some limitations in two-photon stereolithography now and in the future.
[0007] One-photon based microstereolithography techniques fabricate in a surface layer-by-layer approach that ultimately limits the process to rapid prototyping and some small production runs of micropolymer structures. The surface layer-by-layer approach also limits the geometries of objects that can be fabricated due to surface tension or release layer issues, and requires an extensive network of support structure to be digitally inserted into three-dimensional models via support structure insertion algorithms. All of these factors limit the fabrication process and slows the overall throughput of micropolymer structures.
[0008] There also exists a gap between prototyping of complex micro geometries using microstereolithography and mass production of complex geometries. The ideal microstereolithography device would allow any complexity in geometry, need no support structure, and enable rapid prototyping, mass-production, and mass customization from a single machine. Two-photon absorption can occur in two forms: degenerate and non-degenerate. The process is known as degenerate if the photons absorbed are of the same wavelength. The process is known as non-degenerate when the photons absorbed are of two-different wavelengths. Nearly all of the research conducted on two-photon polymerization has been limited to degenerate schemes using a single focused laser beam.
[0009] Non-degenerate two-photon polymerization, using two lasers of two different wavelengths, increases set-up costs, requires optical hardware having a more complex configuration and dual laser pulse synchronization. However, a non degenerate configuration offers distinct advantages that have an impact on the overall throughput and versatility of the fabrication system. Non-degenerate systems offer more control over the geometry of the reaction volume due to the fact that the reaction volume is confined only to the overlapping beams of the appropriate wavelengths.
[0010] The rate of degenerate two-photon absorption, in a dual intersecting beam degenerate two-photon configuration, increases where the two beams intersect but photo-absorption also occurs in the light path prior to the desired reaction volume if the beams enter a sample already tightly collimated, or at a low numerical aperture. This configuration causes some two-photon absorption (TPA) in the beam delivery paths with an increase in absorption occurring at the intersection of the two beams, thus limiting the overall irradiance that is deliverable to the desired fabrication volume. This situation also limits the achievable speed of photopolymerization and feature size resolution.
[0011] For two-photon polymerization photon absorption in the beam's delivery path is an undesired effect and is solved by implementing a focusing scheme with a high numerical aperture. The increase in the probability for absorption to occur as the beam approaches the focal point reduces the possible degenerate configurations to designs that have a high numerical aperture objective lens. Thus there is a need for a two-photon projection microstereolithography method that incorporates a non-degenerate two-photon approach to projection micro stereolithography but which is not subject to the limitations of the known methods. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in this art how the identified needs could be met.
SUMMARY
[0012] The long-standing but heretofore unfulfilled need for improvements in microstereolithography is now met by a new, useful and nonobvious invention. The novel two-photon projection microstereolithography process_incorporates an innovative non-degenerate two-photon approach to projection_microstereolithography.
[0013] More particularly, non-degenerate two-photon_absorption enables single-step, all digital, mass fabrication of micro-polymer or_polymer-derived-ceramic structures of virtually any three-dimensional geometry_directly from computer model design files. This single-step fabrication process is for convenience referred to as the Polymer Object Optical Fabrication (POOF)_process, which acronym suggests the extremely fast microfabrication of three-dimensional_micro polymer structures of unlimited complexity in part geometry_including virtually any aspect ratio desired.
[0014] The POOF process further evolves the known stereolithography process by taking a projection-based, non-degenerate two photon induced photopolymerization (TPIP) approach to stereolithography. Incorporating a spatial light modulator such as Texas Instrument's Digital Light Processor (DLP™) projection technology into the two-photon fabrication process introduces a highly parallel approach to microstereolithography that substantially reduces or eliminates the need for support structure, provides unlimited part geometrical complexity (within a finite range of micro resolution smallest feature sizes) in resulting parts, and provides the optical and mechanical configuration that enables rapid prototyping, high-volume mass-production, and mass-customization of micro polymer and micro-polymerderived-ceramic structures from a single machine in a single step.
[0015] This process is used in conjunction with photoinitiators with a high two-photon absorption cross-section combined with various acrylates, vinyl ethers, epoxies, bio-degradable hydrogels, elastomers, or polymer-derived-ceramics to make complex microstructures for Micro Electro Mechanical Systems (MEMS) and integrated complex three-dimensional optical circuitry for MicroOptoElectroMechanical (MOEMS) devices for a wide range of industries. POOF technology will be an integral tool in the development of polymer and ceramic-based MEMS and MOEMS technologies with a special emphasis on packaging fabrication for current and emerging MEMS and MOEMS' devices.
[0016] The fabrication capability of the POOF process enables the fabrication versatility and throughput of micro geometries currently not feasible with existing fabrication techniques.
BRIEF DESCRIPTION OF THE VIEWS OF DRAWINGS
[0017] FIG. 1 is a diagrammatic side elevational view of a first embodiment;
[0018] FIG. 2 is a diagrammatic end view of the FIG. 1 structure;
[0019] FIG. 3 is a diagrammatic top plan view of the FIG. 1 structure;
[0020] FIG. 4 is a diagrammatic end view of a second embodiment;
[0021] FIG. 5 is a diagrammatic side elevational view of the second embodiment;
[0022] FIG. 6 is a diagrammatic side elevational view of a third embodiment; and
[0023] FIG. 7 is a diagrammatic top plan view of said third embodiment.
DETAILED DESCRIPTION
[0024] This invention includes a method for the patterned solidification, desolidification, or modification of the index of refraction of a photo reactive material by non-degenerate two-photon absorption thereby providing rapid fabrication of three-dimensional micro-structures directly from computer models.
[0025] The steps of the novel method include: Placing a medium capable of selective solidification, desolidification, or refractive index modification via non-degenerate two-photon absorption into a container having at least one optically transparent window so that the medium within the container is accessible by laser light. In the alternative, the entire container may be made of an optically transparent material; Providing an array of controllable pixel elements; Selecting two synchronized pulsed laser sources having respective wavelengths to induce non-degenerate two-photon polymerization; Providing an optical projection system for projecting patterned images of femtosecond pulsed laser light; Directing femtosecond laser pulses onto the array of pixel elements, so that a desired patterned portion of source light travels through the window of the container and into the photoreactive material and focuses inside the photoreactive material;
[0026] Providing an optical system for producing the sheet of light of picosecond pulsed laser light so that sheet has an optimal thinness and flatness, Aiming the femtosecond patterned light and the picosecond sheet of light so that they intersect one another orthogonally with the two focal planes overlapping. More particularly, directing picosecond pulses in a thin, flat sheet so that said picosecond pulses intersect with the femtosecond pulses, such that the thin, flat sheet of picosecond pulses intersects the source light perpendicular to the projected source from the array of pixel elements so that select regions of the photoreactive material are cured at the intersection;
[0027] Positioning the container and the photoreactive material therewithin relative to the intersecting focal planes at an angle less than the critical angle of the container material and photoreactive material; Monitoring the real-time velocity of the container through the light intersection region by employing a velocity sensor; Providing a computer control system that sends electronic data for each image pattern to be projected from the controllable pixel element where the refresh rate of the controllable pixel array is throttled according to the velocity data obtained from the velocity sensor. In the alternative, the feedback could alter the conveyor speed, control the laser repetition rate, the light path length, or the controllable pixel array. A finely tuned system may not require feedback;
[0028] Providing a computer-executable program for extracting a series of slices of a three-dimensional computer model data into a series two-dimensional image files that are compatible with the controllable pixel elements; Sequentially sending the sequence of two-dimensional images extracted from the three-dimensional computer model file to the controllable pixel array, thereby enabling projection of the slices of the computer model file into the medium as the medium volume translates through the intersecting focal planes at a velocity determined by the photo reactive cure time of the photoreactive material and the real-time velocity feedback data; and Synchronizing overlapping pulses operating at two different wavelengths that are of preselected energies to meet the combined energy requirements necessary to achieve non-degenerate two-photon absorption in the beam intersection volume within the photoreactive material.
[0029] The array of controllable pixel elements may include a spatial light modulator and the spatial light modulator may include a plurality of mirrored surfaces each independently pivotable from a first to a second position or state allowing directional control of the area of light reflecting from each mirror. The spatial light modulator is controlled by digital electronics that modify each mirror state by loading a binary array of data. Each bit of data in the binary image array determines the directional pivot of the mirror thus providing spatially patterned projection of laser pulses. The binary array of mirror state data is provided by two-dimensional slice plane image data that is programmatically extracted from a three-dimensional computer model.
[0030] The two-dimensional slice plane data extracted from the computer model is in some cases an exact two-dimensional cross-section replica of the desired fabrication geometry and in other cases the extracted slice plane data is processed in such a way as to use the spatial light modulator as a digital programmable holographic grating capable of projecting a holographic image into the medium. The illuminating pulsed laser light of the spatial light modulator is a femtosecond pulsed laser source.
[0031] An optical system couples with the spatial light modulator to form a laser illuminated projector that has an aspheric beam shaping condenser lens placed prior to and directed onto the spatial light modulator, a micromirror array spatial light modulator, and a reducing imager lens placed post spatial light modulator and focused to intersect sheet of light. This invention is not limited to a micromirror array spatial light modulator. There are many types of spatial light modulators and all of them are within the scope of this invention.
[0032] The aspheric condenser lens redistributes the Gaussian energy distribution of the femtosecond laser light to form a more even energy distribution across the spatial light modulator and thus across the projected focal plane, and the projected image is directed into a region that will allow intersection with the picosecond light sheet and allow the medium and windowed container/cuvette to pass through the intersection region.
[0033] Alternatively, the optical imager lens can be used to expand or reduce the total area of the projected image thus decreasing or increasing the build resolution respectively. The sheet of light optical system is capable of creating a thin sheet of pulsed radiance energy from the picosecond source using an aspheric beam shaping cylindrical lens set placed between the picosecond laser source and the beam intersection volume or “fabrication plane.” The aspheric beam-shaping cylindrical lens set redistributes the picosecond laser light Gaussian energy distribution to form a more even energy distribution across the thin light sheet.
[0034] The thin sheet of pulsed energy is directed into the vat perpendicular to the focal plane of the femtosecond projected image. Alternatively, the sheet of light optical system can be designed from a diffractive optical element that forms a sheet of light that intersects the focal volume of the projected source. The photoreactive material includes a highly efficient two-photon photoreactive initiator material combined with compatible fast reacting monomers such as acrylates, vinyl ethers, epoxies, biodegradable hydrogels, elastomers, or polymer-derived-ceramics.
[0035] The medium may be a liquid resin that is solidified upon exposure to the intersecting beams thus allowing microstructure fabrication. It may also be a solid that is desolidified upon exposure to the intersecting beams thus allow microstructure fabrication. It may also be a material with the capability of altering the index of refraction thus enabling the fabrication of waveguides.
[0036] The novel POOF process incorporates a spatial light modulator such as Texas Instrument's digital light processor @LP™) Projection technology into a two-photon fabrication process. It requires a non-degenerate approach to the TPIP process due to the geometry of the projected light entering the bulk volume of the polymer. The POOF process further requires that the projection system be illuminated by a high peak-power, femtosecond, pulsed, laser source operating at a specific wavelength λ i which projects a series two dimensional slices of a three dimensional computer model.
[0037] The pulsed image is projected into the bulk fabrication volume of photopolymer material through a reducing imager lens of approximately 1.1:1 or greater reduction A high peak-power, nanosecond, pulsed, very thin, flat sheet of laser light operating at a specific wavelength λ 1 , orthogonally intersects the pulsed image at the focal plane of the projection imager lens. At this junction of the femtosecond pulsed image and the thin sheet of picosecond pulsed light the two different wavelengths of light, λ 1 and. λ 2 , will induce non-degenerate TPA thus initiating the free-radical or cationic TPIP process of an entire digitally patterned two-dimensional slice of a computer model in each synchronized dual pulse intersection.
[0038] This intersection of femtosecond projected pulsed images intersecting with picosecond pulsed sheet of light is a significant feature of the invention. Non-degenerate two-photon absorption increases the overall complexity of the machine design by requiring two synchronized pulsed lasers. However, another advantage in implementing this configuration exists in the versatility to alter the beam intersection geometry. This allows alteration of the fabricated voxel geometry. Non-degenerate two-photon scheme also enables utilization of lower numerical apertures in a two-photon polymerization process.
[0039] This versatility is inherent in the non-degenerate two-photon absorption process because two-photon absorption will only occur in the volume of the pulses intersection where the combined irradiance of each beam plays a contribution to meeting the quadratic irradiance dependence required for TPIP. To ensure an optimized microstereolithography process capable of high volume mass production, the projected image is directed into a vat or cuvette at an angle less than the critical angle of the a transparent vat/cuvette wall and the photopolymer material. This critically important aspect of the POOF configuration meets five crucial conditions during the fabrication of the desired object: A) a static focal plane, B) substantially static optical components in the optical path (excluding minute vat vibration), C) constant velocity translation in a single axis, D) substantially turbulence free photopolymer build volume, and E) an array of up to 4.1 million fabricated voxels digitally projected via a high performance spatial light modulator such as the extremely high performance Texas Instrument's Digital Micromirror Device (DMD).
[0040] From an optical, mechanical, and software design perspective, meeting these five important design constraints produces a microstereolithography process that is optimized for high-speed, high-volume microfabrication. Meeting these design constraints also identifies the overall novelty of the POOF technology in an all digital, high-speed, non-degenerate two photon, projection, microstereolithography device for high-volume 3D microfabrication of any geometry.
[0041] The basic POOF system includes an enclosed transparent vat containing a two-photon photoinitiator monomer concentration that is meets the criteria of one-photon optical transparency of each of the POOF process's dual synchronized lasers.
[0042] The vat is mounted to a low vibration translation system that translates the vat at a constant velocity through the fabrication plane where the pulsed image and sheet of light intersect. The DLP™ Projection system projects a series of high peak power femtosecond pulsed cross-sectional CAD model slice image at a refresh rate defined by the velocity of the translation system and the polymerization rate of the photoreactive material. A picosecond pulsed thin sheet of light is synchronized to intersect the projected pulsed image in the focal plane. Because of numerical apertures of the light entering the photopolymer volume, the wavelength of light, and the irradiance of the pulsed laser light neither single beam alone can induce immediate TPIP. A liquid volume goes in and “POOF,” the three-dimensional part is produced. The thickness of each fabrication slice is determined by the non-degenerate TPIP dynamics of the spatial thickness of the sheet of light interacting with the temporal length of the femtosecond projected pixel in the physical intersection geometry and also by any diffusion of the light as photopolymerization occurs and the termination coefficient of the polymer chain during the reaction.
[0043] Further empirical exploration of the intersection beam geometries, with each of the best material candidates, is required to determine the optimal balance of intersecting femtosecond pulse energy dose and picosecond pulse energy dose range that will induce non-degenerate TPIP without causing thermal damage during the fabrication process while maintaining the highest possible throughput of the system.
[0044] The POOF process laser systems and optical systems are chosen by meeting the criteria that TPIP occurs only in the intersection volume of the laser beams. Exposing the photopolymer material to either the projected femtosecond pulsed image of wavelength. λ 1 or the picosecond pulsed sheet of light of wavelength λ 2 , alone will not induce immediate TPIP. Only where the beam operating at λ 1 intersects with a second beam operating at λ 2 , where λ 1 and. λ 2 , are of the appropriate combined energies, will the energies sum to induce immediate TPIP.
[0045] The picosecond pulse sheet thickness and collimation is constrained to an irradiance limitation below the irradiance induced damage threshold of the photopolymer materials. The optimal theoretical light delivery system working in conjunction with the optimal chemical and hardware configuration facilitates a process capable of high volume production of polymer-based micro-structures with the unprecedented combination of three-dimensional complexity, feature size resolution, and volume throughput. Several conceptual TPIP projection POOF design configurations for mass production are depicted in the drawings that include designs for rapid prototyping or rapid manufacturing of polymer or polymer-derived-ceramic microstructures and a design for high resolution rapid prototyping of micro-feature build resolution of macrostructures.
[0046] To fully optimize the overall throughput of this system an optional hardware addition to the overall system is realized by incorporating a magnet that creates a thin, sheet-like, magnetic field across the pulsed light intersection region also called the fabrication region. It is known that photopolymers located in a moderate magnetic field can have an increase in the overall photoefficiency of the photopolymerization process. However, no prior art in the field of stereolithography or TPIP configurations has incorporated a thin magnetic field into the focal region of the incoming light. Increasing the overall photoefficiency of the process results in either lower pulse power requirements to achieve TPIP or an increase in the overall fabrication throughput of the process.
[0047] FIGS. 1-3 depict a typical set-up, which is denoted as a whole by the reference numeral 10 . Conveyor system 12 carries container 14 through the fabrication region. As mentioned above, at least part of container 14 is optically transparent. The depicted conveyor system includes a sprocketed belt 16 that makes a continuous path of travel around sprocket pulleys 18 a , 18 b that are longitudinally spaced apart from one another and which are respectively supported by vibration isolation base members 19 a , 19 b having support legs 20 a , 20 b . Optically flat glass tracks 22 provide a guided path for container 14 through the fabrication region is itself supported by base members 21 a , 2 1 b and support legs 23 a , 23 b.
[0048] Of course, the art of machine design includes numerous equivalent structures for carrying a container along a predetermined path of travel and all of such equivalent structures are within the scope of this invention. The femtosecond pulsed laser is denoted 24 and the picosecond pulsed laser is denoted 26 . The spatial light modulation (SLM) projection system associated with femtosecond pulsed laser 24 is denoted 28 and the femtosecond pulsed laser 24 illuminated projection optics is denoted 30 .
[0049] The femtosecond pulsed laser images projected by SLM projection system 28 are denoted 32 . These images are also referred to as the image source light. The flat sheet of picosecond pulsed laser light is denoted 34 is illuminated by the picosecond pulsed laser denoted 26 and formed by the sheet of light optics denoted 35 .
[0050] The intersection where the synchronized laser pulses meet, i.e., where images 32 meet flat sheet 34 , is denoted 36 . Intersection 36 is the fabrication region. Thin magnet 38 is positioned in an inclined plane and intersects fabrication region 36 . The structure diagrammatically depicted in FIGS. 4 and 5 differs from the structure of FIGS. 1-3 in that no magnet 38 is provided in this embodiment.
[0051] In all other respects, the structure is the same as indicated by the reference numerals, which are common to FIGS. 1-5 . A third embodiment is depicted in FIGS. 6 and 7 . Most of the functional parts are the same as in the first two embodiments as indicated by the common reference numerals. However, instead of a relatively small container 14 that contains the photoreactive material, a large vat 40 contains said material.
[0052] Vertical lifting platform 42 is positioned inside said large vat and suitable means are provided for elevating said platform 42 in increments that correspond to the vertical height of the fabrication region 36 as the inventive method is performed. Vat 42 is supported by a dual axis translation system that includes rigid arms 44 , 46 disposed at a right angle relative to one another at the base of vat 42 , externally of said vat. Translation of vat 42 along an x-axis is controlled by arm 44 , along a y-axis by arm 46 , and along a z-axis by vertical lifting platform 20 42 . The z-axis is perpendicular to the plane of the paper in FIG. 7 . In this way the photoreactive material is moved through fabrication region 36 as vat 40 is translated along said axes under the control of a computer.
[0053] It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
[0054] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall there between. Now that the invention has been described. | High-volume mass-production and customization of complex three-dimensional polymer and polymer-derived-ceramic microstructures are manufactured in a single step directly from three dimensional computer models. A projection based non-degenerate two-photon induced photopolymerization method overcomes the drawbacks of conventional one and two-photon fabrication methods. The structure includes dual, synchronized, high-peak power, pulsed femtosecond and picosecond lasers combined with spatial light modulation. Applications include high-resolution rapid prototyping and rapid manufacturing with an emphasis on fabrication of various Micro-Electro-Mechanical Systems (MEMS) devices, especially in the area of MEMS packaging. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention refers to a liquid crystal display and drive method thereof, and particularly to a TFT active matrix display and drive method thereof for low power consumption.
2. Related Background Art
A prior art liquid crystal display is disclosed, for example, as a liquid crystal display to get a high definition display image in the Official Gazette of Japanese Patent Laid-Open NO. 133629/1998 discloses. Another example is disclosed in the Official Gazette of Japanese Patent Laid-Open NO. 113876/1997 where a polarity inversion circuit is connected to an opposite electrode to ensure stable operation and low power loss. The Official Gazette of Japanese Patent Laid-Open NO.104246/1995 discloses an active matrix liquid crystal drive for lower power consumption.
The following describes the prior art TFT active matrix drive system:
A line sequential scanning system is used to drive the TFT active matrix liquid crystal display, and one scanning pulse is applied to each scanning electrode for each frame time. About 1/60 second is appropriate as one frame time. These pulses are applied downwardly from the top of the panel to the bottom in sequence at differently timed intervals. Consequently, 480 gate wires are scanned in one frame in a liquid crystal display having a 640×480-dot pixel configuration, so the time range of the scanning pulse is about 35 microseconds.
Meanwhile, the liquid crystal drive voltages applied to liquid crystals for one-row pixels where scanning pulses are applied are simultaneously applied to the signal electrode in synchronization with scanning pulses. In the selection pixel where gate pulses are applied, the gate electrode voltage of the TFT connected to the scanning electrode is increased to turn on the TFT. In this case, liquid crystal drive voltage is applied the display electrode via the source and drain of the TFT to charge the pixel capacity comprising the liquid crystal capacity formed between the display electrode and opposite electrode formed on the opposite substrate, plus load capacity assigned to the pixel. This operation is repeated to allow liquid crystal application voltage to be applied repeatedly to the pixel capacity of the all panel surfaces for each frame time.
Since a.c. voltage is required to drive the liquid crystal, the voltage with the polarity inverted for each frame time is applied to the signal electrode. As a result, even if the image to be displayed does not change, much of the power to drive the panel is consumed to repeatedly charge or discharge, at every gate selection, the capacity at the crossing portion between scanning and signal lines or the capacity of the liquid crystal between the line and the opposite electrode formed on all surfaces of on the opposite substrate.
The Official Gazette of Japanese Patent Laid-Open NO.258168/1997 discloses a technology to solve said problem and to implement a liquid crystal display of lower power consumption.
The liquid crystal display disclosed in the Official Gazette of Japanese Patent Laid-Open NO.258168/1997 has the following components in each of the pixel areas enclosed by multiple scanning electrodes and multiple signal electrodes of a substrate; (1) a display data retention circuit connected to corresponding scanning electrodes and signal electrodes to capture and retain the display data from signal electrodes in response to scanning signals, (2) a switching element connected to the display data retention circuit wherein switching operation is controlled by said circuit, and (3) a display electrode connected to the switching element. Display electrode drive voltage is changed in response to the data retained by the display data retention circuit, thereby controlling pixel indications.
The display data retention circuit has a sampling TFT where the gate is connected to the corresponding scanning electrode and the drain is connected to the corresponding electrode, and a sampling capacitor connected to the sampling TFT source. The switching element has a switching TFT where the gate is connected to the source of the display data retention circuit and the source is connected to said display electrode. The sampling capacitor comprising said display data retention circuit and the drain of the switching TFT connected to the display electrode are connected to the common electrode.
The display data retention circuit sends to the sampling capacitor via the sampling TFT the display data signal voltage fed from the signal electrode in synchronism with the scanning signal to select the scanning electrode, and retains the pixel display data as voltage information.
The liquid crystal drive voltage controlling the light and dark pattern of the pixel is determined by a.c. voltage applied to the liquid crystal held closely between the display electrode and opposite electrode. When liquid crystal drive power voltage is applied to the opposite electrode, the voltage is applied to the liquid crystal if the switching TFT is on, but not applied to the liquid crystal if said switching TFT is off. This arrangement allows liquid crystal applied voltage of each pixel to be controlled by the display data signal voltage in the pixel.
In this case, the display data retention circuit can continue to retain the display data until voltage across the sampling capacitor as display data signal voltage is discharged below the threshold voltage of the switching TFT due to leakage of switching TFT or the like. Time until said discharge occurs depends on the leakage current value of the switching TFT and the capacity of the sampling capacitor. Normally, the TFT leakage current value is very small, but is sufficiently longer than 16.6 ms—a representative value of frame time. Moreover, liquid crystal drive voltage can be applied to all pixels in one operation from the opposite electrode. For pixels where display contents do not change, display can be maintained by application of liquid crystal drive voltage alone if the display data signal voltage is changed and the switching TFT is turned on or off. Scanning signal and display data signal voltage should be applied only when display contents are to be rewritten. This ensures excellent display while keeping low power consumption inside the panel.
However, said prior art has a problem that much is required to rewrite the image in response to changes of display contents.
Voltage across the sampling capacitor changes in response to changes of display contents, and this involves changes in the state of the switching TFT. In this case, if the switching TFT changes from OFF to ON state, the voltage of the display electrode will become the same as that of the common electrode immediately. Voltage will be applied to the liquid crystal to get the desired display.
However, if switching TFT is changed from the ON to OFF state, the display electrode is in the floating mode while voltage between the display electrode and opposite electrode is retained, so d.c. voltage will be applied to the liquid crystal between the display electrode and opposite electrode. The desired display cannot be obtained. This d.c. voltage is reduced by liquid crystal leakage, but the time constant for this reduction is long. Complete switching takes much time.
Although the TFT leakage current is very small, it is not zero. The voltage stored in the sampling capacitor cannot be retained for a long time. This makes it necessary to make up for the voltage reduced by leakage whenever required, even if there is no change in display contents. In other words, overwriting is sometimes necessary. When overwriting, the voltage of the sampling capacitor is changed by making up for it. However, if this change affects the state of the switching TFT, the image will change; this is not preferred. In other words, this requires the sampling capacitor voltage to be overwritten without changing the state of the switching TFT.
When overwriting, pulse signals are normally applied to the scanning electrode, and voltage corresponding to the display of pixels for one row is applied to the signal electrode in one operation in synchronism with pulse signals. In this case, a latch circuit is required to output the synchronized voltage to the signal electrode. If the drive circuits of the signal electrode and scanning electrode are built in the liquid crystal panel using a polysilicon or the like, it is preferred to omit the use of the latch circuit, thereby reducing the circuit size. In this case, the voltage of the scanning electrode in the corresponding row is reduced below the threshold value of the sampling TFT, and the signal electrode voltage is rewritten into voltage corresponding to the display for the row. However, the following operation error will occur in this case.
According to the method where the latch circuit, voltage corresponding to the display of pixels on the same column of the preceding row remains in the signal electrode when the voltage of the scanning electrode is reduced below the threshold value of the sampling TFT. Consequently, the data corresponding to pixels on the same column of the preceding row will be written into the sampling capacitor. Normally, the desired data are written immediately thereafter, so there is no problem. If the display data in the same column of the preceding row is on, and the display data to be written is off, then an operation error will occur.
Namely, the switching TFT changes from ON to OFF state with a.c. voltage applied to the liquid crystal. So d.c. voltage is applied to the liquid crystal between the display electrode and opposite electrode as described above, with the result that the desired display cannot be obtained.
According to said technology, the switching TFT may be turned off depending on the screen to be displayed. Since the power of the liquid crystal display is turned on, for example, unwanted d.c. voltage having occurred when power is turned on will remain applied to the electrode of the pixel where the switching TFT is off. If the pixel electrode is always kept is in the floating mode during the drive, the voltage will become unstable. This is not to be preferred.
Problems described above are unique to said technology where display is given with the pixel electrode kept in the floating mode. Such problems do not occur in the prior art technologies disclosed in the Official Gazette of Japanese Patent Laid-Open NO.133629/1998, Official Gazette of Japanese Patent Laid-Open NO.113876/1997 and Official Gazette of Japanese Patent Laid-Open NO.104246/1997 where switching elements are not used.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a liquid crystal display and drive method thereof, featuring a lower power consumption and high speed display switching, based on the method where display is performed with the pixel electrode kept in the floating mode.
Another object of the present invention is to provide a liquid crystal display and drive method thereof, featuring a lower power consumption and high speed display switching, based on the method where display is performed with the pixel electrode kept in the floating mode; said liquid crystal display further characterized by a simple circuit configuration and a function of preventing d.c. voltage from being applied to the liquid crystal when the switching TFT is changed from ON to OFF state.
Still another object of the present invention is to provide a liquid crystal display and drive method thereof, featuring a lower power consumption and high speed display switching, based on the method where display is performed with the pixel electrode kept in the floating mode; said liquid crystal display further characterized by a function of preventing d.c. voltage from being applied to the liquid crystal of the pixel where the switching TFT is always off.
The present invention is characterized a liquid crystal display comprising (1) a switching element connected to a display data retention circuit, common electrode and display electrode, said switching element controlling said common electrode and said display electrode according to the voltage retained in said display data retention circuit, and (2) an opposite electrode installed opposite to said display electrode where a.c. voltage vibrating in response to the voltage of said common electrode is applied; wherein display is performed based on the fact that a.c., voltage is applied to a liquid crystal layer when said switching element connects between said display electrode and common electrode, and a.c. voltage is not applied to said liquid crystal layer when said switching element releases connection between said display electrode and said common electrode; said liquid crystal display further characterized in that the state of said switching element is changed from connection between said display electrode and said common electrode to release of said connection, when the voltages of said opposite electrode, said display electrode and said common electrode are made substantially the same by stopping said a.c. voltage applied to said opposite electrode.
The liquid crystal display according to the present invention has the following components in each of the pixel areas enclosed by multiple scanning electrodes and multiple signal electrodes of a substrate; (1) a display data retention circuit connected to corresponding scanning electrodes and signal electrodes to capture and retain the display data from signal electrodes in response to scanning signals, (2) a switching element connected to the display data retention circuit wherein switching operation is controlled by said circuit, and (3) a display electrode connected to the switching element. Display electrode voltage is changed in response to the data retained by the display data retention circuit, thereby controlling pixel indications.
The display data retention circuit has a sampling TFT where the gate is connected to the corresponding scanning electrode and the drain is connected to the corresponding signal electrode, and a sampling capacitor connected to the sampling TFT source. The switching element has a switching TFT where the gate is connected to the source of the sampling TFT of the display data retention circuit and the source is connected to said display electrode. The sampling capacitor comprising said display data retention circuit and the switching TFT connected to the display electrode are connected to the common electrode.
The display data retention circuit captures into the sampling capacitor and retains therein the display data signal voltage fed from the corresponding signal electrode by making the voltage of the corresponding scanning electrode equal to or greater than the threshold value of the sampling TFT. This operation is repeated by scanning row by row to write display data to all pixels. The liquid crystal drive voltage controlling the light and dark pattern of the pixel is determined by a.c. voltage applied to the liquid crystal held closely between the display electrode and opposite electrode.
When liquid crystal drive power voltage is applied to the opposite electrode, the voltage is applied to the liquid crystal if the switching TFT is on, but not applied to the liquid crystal if said switching TFT is off.
The liquid crystal display according to the present invention is characterized in that voltages of the opposite electrode and display electrode are made substantially the same as that of the common electrode when the switching TFT is changed from ON to OFF state. In this case, voltages of the display electrode voltage and common electrode are the same with each other when the switching TFT is on. Consequently, voltages of these three components are made substantially the same if the opposite electrode voltage is made substantially the same as those of the display electrode and common electrode. Said expression “Voltages of these three components are made substantially the same” also means that the voltage applied to the liquid crystal layer, namely, the difference of voltages between the opposite electrode and display electrode (and common electrode) is made not to exceed the threshold value, in addition to the fact that the opposite electrode voltage is made the same as the display electrode voltage (and common electrode voltage).
As described above, if the opposite electrode and display electrode voltages are made substantially the same as that of the common electrode when the switching TFT is changed from ON to OFF state, the display electrode voltage is the same as the common electrode voltage, even if the switching TFT is changed from ON to OFF to keep the display electrode in the floating mode. So d.c. voltage is not applied to the liquid crystal as discussed in the above description of problems.
Drive is given to ensure data of the data retention circuit is rewritten without voltage applied to the liquid crystal, by making the voltages of the opposite electrode and display electrode the same as that of the common electrode when display has switched. As a result, voltage applied to the liquid crystal is zero, even if the switching TFT is changed from ON to OFF state to keep the display electrode in the floating mode. So d.c. voltage is not applied to the liquid crystal as discussed in the above description of problems. If a.c. voltage is applied to the opposite electrode after all data have been rewritten, a.c. voltage is applied to the liquid crystal where the switching TFT is on, and no voltage is applied to the liquid crystal where the switching TFT is off. Then a desired display is selected.
Another type of the liquid crystal display according to the present invention uses a circuit which turns off all switching TFTs after display electrode voltages in all pixel areas are simultaneously made the same as common electrode voltage. When display is switched, switching TFTs are turned off after display electrode voltages in all pixel areas are made the same as common electrode voltage. Under this condition, data stored in the display data retention circuit are rewritten. In this case, the state of the switching TFT is changed while a.c. voltage is applied to the liquid crystal. All switching TFTs are off before data are rewritten. During data rewriting, the state does not change from ON to OFF. In other words, this eliminates the possibility of the problem which may occur when the switching TFT is changed from ON to OFF state.
When the display data of the display data retention circuit is rewritten with a.c. voltage applied to the liquid crystal, or the same display data is overwritten with a.c. voltage applied to the liquid crystal in order to make up for the voltage stored in the sampling capacitor reduced by leakage, data corresponding to the pixel in the same column of the preceding row may be written, if the scanning electrode has reached the threshold value or has exceeded it while the display data signal voltage corresponding to the pixel in the same column of the preceding row still remains in the signal electrode. Normally, the desired data are written immediately thereafter, so there is no problem. If the display data on the same column of the preceding row is on, and the display data to be written is off, then said problem will occur. Namely, the switching TFT changes from ON to OFF state with a.c. voltage applied to the liquid crystal. So d.c. voltage is applied to the liquid crystal as described above, with the result that the desired display cannot be obtained.
To solve this problem, still another type of the liquid crystal display according to the present invention has a latch circuit installed to the signal data write circuit to synchronize the scanning electrode voltage with signal electrode voltage. This ensures that voltage not exceeding the threshold value of the sampling TFT will not be applied to the scanning electrode, when the data of the preceding row remains in the signal electrode.
However, installation of a latch circuit increases the circuit size of the signal data write circuit, so this is not appropriate when the circuit is built in the liquid crystal panel using polysilicon or the like. To solve this problem, the present invention proposes a method which does not use a circuit; a method of resetting the signal electrode voltage to the OFF display data signal voltage for each writing into one row. This ensures all signal electrode voltages are OFF display signal voltage when the scanning electrode voltage is equal to or greater than the threshold value of the sampling TFT, so all the switching TFTs of that row will be turned off. If the original state is on in this case, the state will change from ON to OFF, said problem will occur. However, “ON” will be written immediately thereafter and d.c. voltage is applied only momentarily, so there is no problem.
Another method of solving this problem according to other characteristic of the present invention without installing a latch circuit provides a driving scheme which makes the scanning electrode voltage equal to or greater than the threshold value of the sampling TFT after desired display data signal voltages have been written to all signal electrodes. Furthermore, said problem can be solved, without installation of a latch circuit, by a drive scheme of making the opposite electrode voltage equal to the common electrode voltage at the time of rewriting and overwriting.
The liquid crystal display according to the present invention reduces power consumption by reducing the time period of rewriting or overwriting the display data of the display data retention circuit. The present invention provides a liquid crystal display which reduces the time period of rewriting or overwriting the display data by inputting the address data of the black or white display pixel, instead of inputting the display data corresponding to all pixels.
A further type of the liquid crystal display according to the present invention has a circuit which turns off the switching TFT in said pixel area for at least one row after the display electrode voltages in the pixel area for at least one row are simultaneously made equal to the common electrode voltage. When data is written into the display data retention circuit, the switching TFT is turned off after the display electrode voltage in said pixel area for at least one row is made equal to the common electrode voltage. In that state, data are written to the display data retention circuit in the pixel area for at least one row. In this case, the state of the switching TFT is changed while a.c. voltage is applied to the liquid crystal. The switching TFT is off before data is rewritten. During data rewriting, the state does not change from ON to OFF. In other words, this eliminates the possibility of the problem which may occur when the switching TFT is changed from ON to OFF state. The above operations are performed for all rows and data are written to data retention circuits in all pixel areas. As described above, driving the liquid crystal display allows all display electrodes to be electrically connected with the common electrode every time data is always written to the corresponding display data retention circuit. This eliminates the possibility of the problem of d.c. voltage which may occur the switching TFT based on said technology is off.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram representing the configuration of the first Embodiment according to the present invention;
FIG. 2 shows a circuit configuration of the pixel unit given in FIG. 1;
FIG. 3 is a drawing representing a mask pattern of the pixel given in FIG. 2;
FIG. 4 is a cross sectional view of the pixel given in FIG. 3;
FIG. 5 represents the drive waveform according to the present invention of the first Embodiment;
FIG. 6 shows the voltage level of the drive waveform given in FIG. 5;
FIG. 7 depicts voltage waveforms of the Embodiment and Reference Example according to the present invention;
FIG. 8 is a block diagram representing the configuration of the second Embodiment according to the present invention;
FIG. 9 represents the drive waveform according to the present invention of the second Embodiment;
FIG. 10 is a block diagram representing the configuration of the third Embodiment according to the present invention;
FIG. 11 represents the drive waveform according to the present invention of the third Embodiment;
FIG. 12 is a block diagram representing the configuration of the fourth Embodiment according to the present invention;
FIG. 13 represents the drive waveform according to the present invention of the fourth Embodiment;
FIG. 14 is a block diagram representing the configuration of the fifth Embodiment according to the present invention;
FIG. 15 represents the drive waveform according to the present invention of the fifth Embodiment;
FIG. 16 is a block diagram representing the scanning line selection circuit of the sixth Embodiment according to the present invention; and
FIG. 17 represents the drive waveform according to the present invention of the sixth Embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Embodiments of the liquid crystal display according to the present invention will be described with reference to Figures:
Embodiment 1
FIG. 1 is a block diagram representing the first Embodiment of the liquid crystal display according to the present invention, and FIG. 2 is a circuit configuration view representing the pixel unit given in FIG. 1. A pixel unit 2 are arranged in a matrix of N-row×M-column dots on display unit 1 formed on the TFT substrate. Inside the pixel unit 2 , a display data retention circuit 5 comprising a sampling TFT 10 and a sampling capacitor 11 , a switching TFT 6 , and display electrode 7 used for display are laid out at the crossing point between a scanning electrode 3 and a signal electrode 4 . Each scanning electrode is connected to a scanning line selection circuit, and each signal electrode is connected to the signal data write circuit.
The signal data write circuit comprises a shift register to issue outputs in response to clock signal 1 , a display data signal sampling TFT 101 to sample display data signal in response to shift register outputs, and a data latch circuit which synchronizes the display data signal sampling TFT 101 output with the latch signal and issues voltage VD (i) to the signal electrode in the first column. The scanning line selection circuit consists of a shift register which produces VG(j) to the scanning electrode of the J-th row in response to clock signal 2 .
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Forming these circuits integrally on the TFT substrate using the TFT is effective in reducing the size of the display. It is also possible to use combination with the LSI individually.
Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflective type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The mask pattern of the pixel shown in FIG. 2 is given in FIG. 3, and cross sectional views of A-B and C-D in FIG. 3 are illustrated in FIG. 4 . The following describes the overview of the process forming this TFT substrate:
The amorphous silicon layer is first formed according to the LPCVD method, and is then polycrystallized by laser annealing; then island-formed silicons 50 of the switching TFT 6 and sampling TFT 10 are formed by patterning. Then silicon dioxide layer is formed as gate insulation layer 51 by APCVD method, and the metallic layer is then formed by LPCVD method. After that, two layers of the metallic layer and gate insulation film 51 are patterned by dry etching method, and a gate electrode 52 and bottom electrode 53 of sampling capacity are formed.
Then dopant such as phosphorus ion is implanted into the source and drain areas of the island-formed silicon by ion implantation. This is followed by heat treatment to provide activation for conversion into low resistant n-type silicon, thereby forming a drain electrode 54 a and source electrode 54 b . After formation of a silicon dioxide layer as a TFT protection layer 55 , the first contact hole is formed. After formation of a metallic layer such as Cr, patterning is provided to form signal electrode 4 , top electrode 56 of sampling capacity, connection unit 57 , and connection unit 58 . Via said contact hole, signal electrode 4 is connected to the drain electrode 54 a of the sampling TFT 10 , the top electrode 56 of the sampling capacity to the source electrode 54 b of the sampling TFT 10 , connection unit 57 to the bottom electrode 53 of the sampling capacity and the drain electrode 54 a of the switching TFT 6 , and connection unit 58 to the source electrode 54 b of the switching TFT 6 , respectively.
Furthermore, a second contact hole is formed after an insulation layer 61 is formed using the photosensitive organic film or the like. Similarly, after patterning the photosensitive organic film or the like on the insulation layer 61 by photolithography, irregular shaped layer 62 with smooth irregularities formed on the surface is formed by heating, and a metallic layer having a high reflection factor is formed thereon. Then display electrode 7 is formed by patterning. The process of TFT substrate formation is now complete.
This production process is a low temperature p-Si TFT process. The high temperature p-Si TFT process may be used to get a TFT having excellent mobility and to reduce the TFT size. This has an advantage of providing an easier way of building the peripheral scanning line selection circuit or the like into TFT. In all of the mask patterns shown in FIG. 3, the sampling TFT 10 and switching TFT 6 have a coplanar structure. The sampling capacitor 11 is formed via the TFT protection layer 55 between the top electrode 56 formed by using the same layer as signal electrode 4 and the bottom electrode 53 formed by using the metallic layer of common electrode 8 .
FIG. 3 shows the configuration where no other component is present between adjacent display electrodes 7 . If TFT is formed on the glass substrate, it is transparent between display electrodes; therefore, light reflected on this portion will not be reflected. This portion has no display electrode, so a desired voltage is not applied. Therefore, if there is any component reflecting light it will result in increase of unwanted reflected light component, thereby reducing contrast. However, unwanted reflection will be eliminated by layout of the display electrode as shown in FIG. 3, thereby allowing a high contrast ratio to be ensured.
The following describes the operation principle of the first Embodiment of the liquid crystal display by the present invention comprising N-row×M-column pixels, using the drive waveform shown in FIG. 5 and voltage level shown in FIG. 6 . Here the display data signal voltage to write i-column by j-row pixels into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) denotes either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by three periods; write period, retention period and overwrite period. When display has switched, it is driven in the order of write period, retention period, overwrite period, retention period, overwrite period, etc. If display does not change, it is driven in the order of retention period and overwrite period repeatedly. Write period are used only when display has been switched.
During the write period, the voltage VC of the opposite electrode is made equal to the voltage VCOM of the common electrode. Therefore, the voltage VS of the display electrode 7 will be VS=VC=VCOM, so voltage is not applied to the liquid crystal (VC−VCOM=VLC=0).
Signals which select the signal electrode 4 sequentially are issued from the shift register in response to clock signal 1 . The display data signal is synchronized with the clock signal 1 . Display data signals V (i, j) are produced when the signal electrode in the i-th column is selected. Accordingly, display data signal V (i, j) is captured into the data latch circuit corresponding to specified signal electrode by the display data signal sampling TFT 101 . After display data signals corresponding to the M signal electrodes have been captured, display data signal VD (i)=V (i, j) (i=1 through N) are output simultaneously to all signal electrodes synchronously with latch signal. VD (i′)=V (i′, j)=VDH is issued to the signal electrode connected to the pixel (i′, j) where display is on, while VD(i″)=V(i″, j)=VDL is issued to the signal electrode connected to the pixel (i″, j) where display is off. In this case, the scanning line selection circuit selects the corresponding scanning electrode to produce the VG (j)=VGH, concurrently as display data signals are issued from the latch circuit in response to clock signal 2 . (Voltages of other scanning electrodes are VGL). Namely, voltage not less than the threshold value Vth of the sampling capacitor is applied to the scanning electrode. The sampling TFT 10 of pixel (i, j) where the voltage VG(j) of the connected scanning electrode has become VGH captures voltage VD (i) of the connected signal electrode 4 , and stores voltage VD(i)=V (i,j) in the sampling capacitor 11 . The above operations are repeated N times equivalent to the number of the scanning electrodes, and data of the display data retention circuit for all pixels are rewritten, thereby terminating the write period.
Then the operations of clock signal 1 , display data signal, latch signal, and clock signal 2 are stopped (low level signals are issued), and a.c. voltage VC is applied to the opposite electrode (retention period). During this retention period, voltage VM retained in the sampling capacitor 11 is changed by the leakage of sampling TFT or the like. However, the length of the period is set to ensure that the voltage VDH written into the pixel where display is on is not less than voltage VMH required to turn on the switching TFT 6 throughout the retention period, and the voltage VDL written into the pixel where display is off does not exceed voltage VML required to turn off the switching TFT 6 throughout the retention period. Accordingly, during the retention period, the switching TFT 6 of the pixel where display is on is in the state of connection (ON state), while the switching TFT 6 of the pixel where display is off is in the state of non-connection (OFF state). So as shown in FIG. 5, the voltage VS (i, j) of the display electrode 7 of the pixel where display is on is equal to the voltage VCOM of the common electrode (solid line), whereas the voltage VS (i, j) of the display electrode 9 of the pixel where display is off is equal to the voltage VC of the opposite electrode 9 (broken line). Since voltage VLC (i, j)=VC−VS (i, j) is applied to the liquid crystal, a.c. voltage with amplitude V0 is applied to the liquid crystal of the pixel where display is on (solid line), while voltage is not applied to the liquid crystal of the pixel where display is off (broken line).
In the ensuing overwrite period, voltage changed due to leakage and stored in the sampling capacitor 10 is written again. In this case, since display does not change, a.c. voltage is applied to the opposite electrode, as in the case of retention period. In other words, the operation is the same as that in the write period, except that VC is a.c. voltage. Similarly to the write period, voltage synchronous with scanning electrode voltage from the latch circuit is issued to the signal electrode, and is captured by the corresponding sampling TFT 10 to be stored in the sampling capacitor 11 . In this case, voltage stored in the sampling capacitor 11 changes from VMH to VDH or from VML to VDL in response to display. This change does not affect the state of switching capacitor 6 , so the voltage applied to the liquid crystal does not change. In other words, the display is not affected.
According to the prior art, display data signal voltage written into the pixel via the signal electrode is written into the display electrode, and is applied directly to the liquid crystal. According to the present invention, voltage to control display state is applied to the sampling capacitor, unlike the prior art. After having been written into the sampling capacitor, the stored display data signal voltage is changed gradually by leakage of the sampling TFT during the period before the scanning electrode is selected again in the overwrite period. However, display quality does not change until change is made in excess of the threshold value voltage of the switching TFT. This makes it possible to provide a sufficiently long retention period.
According to the present Embodiment, the voltage VC of the opposite electrode is made equal to voltage VCOM of the common electrode during the write period as described above, so that voltage is not applied to the liquid crystal. This arrangement permits immediately switching of display. FIG. 7 in a Reference Example shows the waveform of the voltage applied to the liquid crystal when display is switched with a.c. voltage applied to the opposite electrode VC, and voltage waveform according to the present Embodiment. It shows a voltage waveform when voltage VM stored in the sampling capacitor 11 has switched from VDH to VDL, namely, display has switched from ON to OFF.
The case of Reference Example corresponds to the state where the switch is opened when a.c. voltage VC is applied to the liquid crystal, as shown in the equivalent circuit in FIG. 7 .
In this Figure, VC changes by 2V from −V0 to +V0 immediately after the switch is opened. In this case, the circuit is released, so voltage applied to the liquid crystal is retained (VLC=VC−VS=−V0). Namely, the voltage VS of display electrode 7 is VS=VC+VO=2V0. This d.c. voltage is damped by the time constant ερ determined by the dielectric constant ε of the liquid crystal and resistivity ρ. The dielectric constant of normal liquid crystal material is approximately ρ=10×ε0 (ε0=8.854×10 −12 F/m, dielectric constant of free space). The resistivity is approximately ρ=10 12 Ωcm, with time constant of about 0.8854 sec. In other words, about one second is required for switching of display. By contrast, the present invention allows display to be switched immediately after write period. Normally, all pixels are rewritten in 1 frame period (16.6 ms) or less, so the image is switched almost instantly according to the prior art method.
As described above, use of the present Embodiment provides a liquid crystal display featuring lower power consumption and high speed display switching.
In the present Embodiment, voltage VC of the opposite electrode and voltage VS of the display electrode are made equal the voltage VCOM of the common electrode when display is changed from ON to OFF. Here it is sufficient that these three voltages are virtually the same; it is sufficient that voltage equal to or greater than the threshold value is not applied to the liquid crystal layer. This holds good for the following Embodiments.
Use of the first Embodiment allows makes write period as short as 16.6 ms when the number of pixels is 640 by 480 dots, where display is switched almost instantly. However, increase in the number of pixels prolongs write period, and display switching is felt to be slow. For example, to get a 4000×4000-dot high definition display, it will take about 16.6 ms×(4000×4000)/(640×480)=0.9 sec. This means that the write period is very long; one second will be required until the new screen appears. If clock signal frequency is made higher, the write period will be shortened. However, power consumption will increase in proportion to the clock signal frequency. Thus, this is not fitted to implement a lower power consumption and high speed screen switching function.
Embodiment 2
The second Embodiment described below enables high speed display of a new screen at a lower power consumption rate even when there is an increase in the number of pixels. FIG. 8 is a block diagram of the second Embodiment of a liquid crystal display according to the present invention.
The configuration of display unit 1 is the same as the first Embodiment. The signal data write circuit comprises a shift register to produce output in response to clock signal 1 , an OR circuit 102 to issue the output of the shift register and OR signal of reset signal 1 , and a display data sampling TFT 101 to sample display data signal in response to the output of OR circuit 102 and to issue it to the signal electrode. The scanning line selection circuit comprises a shift register to produce output in response to clock signal 2 , an AND circuit 104 to issue the AND signal between the output of the shift register and inversion signal of the reset signal 1 and an OR circuit 103 to issue the output of AND circuit 104 and OR signal of the reset signal 1 .
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflective type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The following describes the operation principle of a second Embodiment of the liquid crystal display comprising N-row by M-column pixels according to the present invention using a drive waveform shown in FIG. 9 . Display data signal voltage to write the i-column by j-row pixel into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) is either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by four periods; reset period, write period, retention period, and overwrite period. When the display has been switched, it is driven in the order of reset period, write period, retention period, and overwrite period, retention period, overwrite period, etc. If display does not change, it is driven in the order of retention period and overwrite period repeatedly. Reset period and write period are used only when display has been switched.
Reset signal 1 and reset signal 2 go high during the reset period. In this case, the outputs of the OR circuit 102 and OR circuit 103 go high despite the state of the shift register, etc. Since the output of OR circuit 102 is of high level, the display data signal is written into all signal electrodes through display data sampling TFT 101 . Since the output of OR circuit 103 is at the high level, voltage of all scanning electrode is VG(j)=VGH, and the display data signals of the signal electrodes are written into the sampling capacitor of all the pixels. The display data signal becomes VDL after having become VDH once during the reset period. So the switching TFTs of all pixels are turned off after having been turned on once. During the reset period, voltage VC of the opposite electrode is equal to voltage VCOM of the common electrode, so display electrode 7 is kept in the floating mode after voltage has become VCOM, thereby retaining voltage VCOM.
In the ensuing write period, voltage V(i, j) in response to display is written into the sampling capacitor of pixel (i ,j) while a.c. voltage is applied to the opposite electrode, unlike in the first Embodiment. In this case, the switching TFT is set to off in the reset period, so there is no change to the OFF state from the ON state where the d.c. voltage is applied to the liquid crystal as explained with reference to FIG. 7 .
Signals to select the signal electrode sequentially are output from the shift register in response to clock signal 1 . Display data signal is synchronized with clock signal 1 , and corresponding display data signal V (i, j) is output when the specified signal electrode is selected. Consequently, display data signal VD (i) (i=1 through N) is sequentially issued to the specified signal electrode by the display data signal sampling TFT 101 . VD(i′)=VDH is issued to the signal electrode connected to the pixel (i′, j) where display is on, while VD(i″)=VDL is output to the signal electrode connected to the pixel (i″, j) where display is off. (See FIG. 6 ).
After above operations have been repeated M times, clock signal 1 stops and VD (i) is retained at the M signal electrodes for a specified time. After that, the reset signal 1 goes high, and display data signals are written into all signal electrodes through the display data signal sampling TFT 101 .
(This period is defined as a horizontal reset period). In this case, display data signals are at the low level (VDL), and VDL is written into all signal electrodes. This period is defined as a horizontal period.
If there is no horizontal reset period in this case, voltage V (i, J-i) written during (j−1)-th horizontal period will remain in the signal electrode, when voltage of the j-th scanning electrode becomes VGH in the j-th horizontal period. As a result, an operation error may occur in the case of V (i, j)≠V(i, j−1). For example, when V (i, j−1)=VDH and V (i ,j)=VDL, the switching TFT 6 of the pixel (i, j) is turned on, since the voltage of the gate becomes V (i, j−1)=VDH through sampling TFT 10 immediately when the voltage of j-th scanning electrode has become VGH. However, the original display data signal V (i, j)=VDL is written during the j-th horizontal period, so the switching TFT is turned off. In this way, the switching TFT changes from ON state to OFF state when a.c. voltage is applied to the opposite electrode. This leads to an operation error where d.c. voltage is applied to the liquid crystal (called operation error caused by the preceding row), as described above. To solve this problem, the present Embodiment makes the voltage of all signal electrodes VGL at the close of the horizontal period of the horizontal reset period, thereby preventing said operation error. Similarly to the first Embodiment, no operation error can possibly be caused by said data in the preceding row even if a latch circuit is installed in the signal data write circuit. Use of the present Embodiment avoids operation errors resulting from said data of the preceding row in a small circuit, without having to employ a latch circuit.
If the shift register output VG′ (j) is directly applied to the scanning electrode when display data signal is written into the sampling capacitor 11 of the j-th row pixel in the j-th horizontal period of the write period, then display data signals v (i, j) written during the horizontal reset period will be rewritten and VGL will be written into all the sampling capacitors of the j-th row pixel. To solve this problem, the present Embodiment applies voltage the scanning electrode in the following manner: During the horizontal period, the shift register of the scanning line selection circuit selects the scanning electrode in response to clock signal 2 in the horizontal period, so high level output is issued to the VG′ (j) in order to select the scanning electrode. The inversion level of the reset signal 1 and the AND signal of the VG′ (j) are output to the scanning electrode So in the horizontal period, VG (j)=VGH is output only during the period where the reset signal is of low level. The sampling TFT of the pixel (i, j) where voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD (i) of the connected signal electrode, and the voltage is retained at the sampling capacitor. Since VG (j)=VGL in the ensuring horizontal reset period, the connected sampling TFT turns off, and VD (i) in response to display is retained, without voltage VDL of the signal electrode during the horizontal reset period being written to the sampling capacitor 11 . The above horizontal period is repeated N times which correspond to the number of the scanning electrodes, and the data of display data retention circuit of all pixels are rewritten, thereby terminating the write period.
In the write period of the second Embodiment, a.c. voltage is applied to the opposite electrode. So before termination of the write period, display is given sequentially, starting from the pixel where display data signal voltage V(i, j) is written into the sampling capacitor. This ensures faster display than that in the first Embodiment when display has switched.
Then the operations of clock signal 1 , display data signal, clock signal 2 , reset signal 1 and reset signal 2 are stopped, and a.c. voltage VC continues to be applied to the opposite electrode (retention period). Voltage VM retained in the sampling capacitor during this retention period varies according to the leakage of the sampling TFT and others. The length of the retention period is set to ensure that voltage VDH written into the pixel when display is on is equal to or greater than the VMH throughout retention period, while voltage VDL written into the pixel when display is off is equal to or greater than the VMH does not exceed VML throughout the retention period. Accordingly, during the retention period, the switching TFT of the pixel where display is on is in the state of connection (ON state), while the switching TFT of the pixel where display is off is in the state of non-connection (OFF state). So as shown in FIG. 9, the voltage VS of the display electrode of the pixel where display is on is equal to the voltage VCOM of the common electrode (solid line), whereas the voltage VS of the display electrode of the pixel where display is off is equal to the voltage VC of the opposite electrode (broken line). Since voltage VLC=VC−VS is applied to the liquid crystal, a.c. voltage with amplitude V0 is applied to the liquid crystal of the pixel where display is on (solid line), while voltage is not applied to the liquid crystal of the pixel where display is off (broken line).
The operation in the ensuing overwrite period is the same as that in the write period. Unlike the write period, an operation error occurs in the overwrite period, but this covers only a very short time without affecting the display. In the overwrite period when display data signal V (i, j)=VDH is overwritten into the sampling capacitor of the j-th pixel during the j-th horizontal period, voltage VGL written into the (j−1)-th horizontal reset period remains in the signal electrode when the voltage of the j-th scanning electrode becomes VG(j)=VGH. Since voltage of VMH or more is retained to the sampling capacitor before the overwrite period, the switching TFT changes from ON to OFF state when a.c. voltage is applied to the opposite electrode immediately when the voltage of the j-th scanning electrode has become VGH. This allows d.c. voltage to be applied to the liquid crystal as described above. In this case, however, V (i, j)=VDH is written immediately thereafter, and the switching TFT is turned on. So d.c. voltage is applied to the liquid crystal only for a very short time, without affecting the display.
In the present Embodiment, this voltage is retained for a specified time period after VD (i) has been issued to all signal electrodes during the horizontal period of the write period and overwrite period; then the voltage of the scanning electrode is made VGL, and reset signal 1 is set to the high level. The operation is also possible if the scanning electrode voltage is made VGL and reset signal 1 is set to the high level, immediately after all signal electrodes VD (i) are output. In this case, however, the period where specified voltage VD(M)=V(M, j) is applied to the M-th signal electrode will be very short. So to write VD(M) into the sampling capacitor 11 , the sampling TFT is required to have a very high performance. The operation is possible when a low performance TFT is used if the scanning electrode voltage is kept at VGH for some time even after the specified voltage VD(M)=V(M, j) is applied to the M-th signal electrode, and a longer time is assigned to write into the sampling capacitor, as in the present Embodiment.
As described above, the present Embodiment provides a liquid crystal display characterized by high definition, lower power consumption, and a high speed display when display has switched.
Embodiment 3
The operation error caused by data in the preceding row can also be solved by a third Embodiment according to the present invention to be described below. FIG. 10 is a block diagram of the third Embodiment of the liquid crystal display according to the present invention.
Display unit 1 is arranged in the same configuration as that of the first Embodiment. The signal data write circuit is arranged in the same configuration as that of the second Embodiment. The scanning line selection circuit comprises (1) a shift register to produce outputs in response to clock signal 2 , (2) an AND circuit 104 to issue AND signals between the output of said shift register and control signal, and (3) an OR circuit 103 to issue OR signals between the output of said AND circuit 104 and reset signal 1 .
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflector type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The following describes the operation principle using the drive waveform shown in FIG. 11 . Here the display data signal voltage to write i-column by j-row pixels into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) denotes either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by four periods; reset period, write period, retention period, and overwrite period. The operations in reset period and retention period are the same as those in the second Embodiment.
In the write period, voltage v (i, j) in response to display is written into the sampling capacitor of the pixel (i, j) while a.c. voltage is applied to the opposite electrode, unlike the case in the first Embodiment. In this case, the switching TFT is off in the reset period, so there is no change to the OFF state from the ON state where the d.c. voltage is applied to the liquid crystal.
Similarly to the case of the second Embodiment, operation errors resulting from said data of the preceding row are avoided without using a latch circuit.
Signals to selects scanning electrodes sequentially in response to clock signal 1 are issued from the shift register. Display data signals are synchronized with clock signal 1 , and a corresponding display data signal V (i, j) is output when a specified signal electrode is selected. Consequently, display data signals VD(i) (i=1 through N) are sequentially output to the specified signal electrode by the display data signal sampling TFT 101 . VD(i′)=VDH is issued to the signal electrode connected to the pixel (i′, j) where display is on, while VD(i″)=VDL is output to the signal electrode connected to the pixel (i″, j) where display is off. (See FIG. 6 ). After above operations have been repeated M times, clock signal 1 stops and VD (i) is retained at the M signal electrodes for a specified time. This period is defined as a horizontal period.
In the horizontal period, the shift register of the scanning line selection circuit issues a high level to VG′ (j) in response to clock signal 2 synchronized with horizontal period to select the scanning electrode. The AND signal between control signal and VG (j) is issued to the scanning electrode, so VG (j)=VGH is output for the period where the control signal is high, namely only for the specified period where said VD (i) is retained. The sampling TFT of the pixel (i, j) where voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD (i) of the connected signal electrode, and the voltage is retained at the sampling capacitor.
The above horizontal period is repeated N times which correspond to the number of the scanning electrodes, and the data of display data retention circuit of all pixels are rewritten, thereby terminating the write period.
In the write period, voltages of all signal electrodes become VGH after the voltage of the j-th scanning electrode has become VD (i)=VD(i, j), so voltage written into the (j−1)-th horizontal period does not affect the j-row pixel.
Operations in the overwrite period are the same as those in the write period. Display data signal in the preceding row does not give any influence. The present Embodiment also provides a liquid crystal display characterized by high definition, lower power consumption, and a high speed display when display has switched.
By using a latch circuit, OR circuit or AND circuit in the signal write circuit and scanning line selection circuit in the Embodiment described above, it is possible to provide a liquid crystal display characterized by high definition, lower power consumption, and a high speed display when display has switched.
Embodiment 4
The fourth Embodiment provides a liquid crystal display which permits the same operations as above Embodiments, using a small-sized signal data write circuit and a scanning line selection circuit without using a latch circuit, OR circuit or AND circuit. The small size of the signal data write circuit and scanning line selection circuit effectively increases the yield when manufacturing these circuits the TFT substrate using a polysilicon TFT or the like.
FIG. 12 is a block diagram representing the fourth Embodiment of a liquid crystal display according to the present invention. Display unit 1 formed on the TFT substrate is the same as that of the first Embodiment. The signal data write circuit comprises a shift register to issue outputs in response to clock signal 1 , and a display data signal sampling TFT 101 to sample display data signals in response to the output of the shift register. The scanning line selection circuit comprises a shift register which issues VG(j)=VGH to the scanning electrode in response to clock signal 2 .
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflector type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The following describes the operation principle of the fourth Embodiment of the liquid crystal display according to the present invention comprising N-row×M-column pixels, using the drive waveform shown in FIG. 13 . Here the display data signal voltage to write i-column by j-row pixels into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) denotes either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by three periods; write period, retention period and overwrite period. When display has switched, it is driven in the order of write period, retention period, overwrite period, retention period, overwrite period, etc. If display does not change, it is driven in the order of retention period and overwrite period repeatedly. Write period is used only when display has been switched. During the write period and overwrite period, the voltage VC of the opposite electrode is made equal to the voltage VCOM of the common electrode. So no voltage is applied to the liquid crystal (VLC=0).
Signals which select the signal electrode sequentially are issued from the shift register in response to clock signal 1 . The display data signal is synchronized with the clock signal 1 . Display data signals V (i, j) are produced when the signal electrode in the i-th column is selected. Accordingly, display data signal v (i, j) is captured into the specified signal electrode by the display data signal sampling TFT. Display data signal VD(i)=V (i, j) (i=1 through N) is sequentially output. VD (i′)=V (i′, j)=VDH is issued to the signal electrode connected to the pixel (i′, j) where display is on, while VD (i″)=V (i″, j)=VDL is output to the signal electrode connected to the pixel (i″, j) where display is off. In this case, the scanning line selection circuit selects the scanning electrode in response to clock signal 2 , and issues VG (j)=VGH. (The voltage of other scanning electrodes is VGL). In other words, voltage equal to or greater than the threshold value of the sampling capacitor is applied to the scanning electrode. The sampling TFT of the pixel (i, j) where voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD (i) of the connected signal electrode, and the voltage VD(i)=V(i,j) is retained at the sampling capacitor. This operation is repeated N times which correspond to the number of the scanning electrodes, and the data of display data retention circuit of all pixels are rewritten, thereby terminating the write period.
Then the operations of clock signal 1 , display data signal and clock signal 2 are stopped, and a.c. voltage VC continues to be applied to the opposite electrode (retention period). Voltage VM retained in the sampling capacitor during this retention period varies according to the leakage of the sampling TFT and others. The length of the retention period is set to ensure that the voltage VDH written into the pixel where display is on is not less than voltage VMH required to turn on the switching TFT throughout the retention period, and the voltage VDL written into the pixel where display is off does not exceed voltage VML required to turn off the switching TFT throughout the retention period. Accordingly, during the retention period, the switching TFT of the pixel where display is on is in the state of connection (ON state), while the switching TFT of the pixel where display is off is in the state of non-connection (OFF state). So as shown in FIG. 13, the voltage VS (i, j) of the display electrode of the pixel where display is on is equal to the voltage VCOM of the common electrode (solid line), whereas the voltage VS of the display electrode of the pixel where display is off is equal to the voltage VC of the opposite electrode (broken line). Since voltage VLC (i, j)=VC−VS (i, j) is applied to the liquid crystal, a.c. voltage with amplitude V0 is applied to the liquid crystal of the pixel where display is on (solid line), while voltage is not applied to the liquid crystal of the pixel where display is off (broken line).
In the ensuing overwrite period, voltage changed due to leakage and stored in the sampling capacitor is written again. Unlike the cases in the first, second and third Embodiments, the opposite electrode voltage is made equal to the common electrode voltage. In other words, no voltage is applied to the liquid crystal. VD (i)=V (i, j) (i=1 through N) are sequentially output to the specified signal electrode. The scanning line selection circuit selects the scanning electrode in response to clock signal 2 , and issues VG (j)=VGH. (The voltage of other scanning electrodes is VGL). In other words, voltage equal to or greater than the threshold value of the sampling capacitor is applied to the scanning electrode. The sampling TFT of the pixel (i, j) where voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD (i) of the connected signal electrode, and the voltage VD (i)=V (i, j) is retained at the sampling capacitor. In the write period, this operation is repeated N times which correspond to the number of the scanning electrodes, and V (i, j) is written into the sampling capacitors of all pixels, but in the overwrite period, the N electrodes are separated into several segments for this writing. In the first overwrite period, for example, clock signal 1 and clock signal 2 are stopped after overwriting into the sampling capacitors of pixels from 1st to k-th rows, and a retention period is provided. In the ensuing second overwrite period, overwriting is made to the sampling capacitors of the pixels from k+1st to 2 k -th. Then the retention period and overwrite period are repeated, and sampling capacitors of all pixels are overwritten using the multiple overwrite period.
Said operation error of d.c. voltage applied to the liquid crystal or said operation error caused by data in the preceding row does not occur in the overwrite period since a.c. voltage is not applied to the liquid crystal.
A longer overwrite period means a longer time when voltage is not applied to the liquid crystal, and a flicker problem is caused by reduced contrast resulting from reduced effective voltage applied to the liquid crystal or intermittent voltage applied to the liquid crystal. There will be a slight reduction of effective voltage if the overwrite period is made sufficiently shorter than the retention period. Then reduced contract does not raise any problem. No flicker occurs if the overwrite period is set, for example, to about 1 ms which is sufficiently shorter than liquid crystal response time. To reduce the overwrite period, however, the number of rows to be rewritten in one overwrite period must be reduced. As a result, a very long time will be required from the first overwriting to the next overwriting, when viewed in terms of one pixel. This requires the leakage of the display data retention circuit to be reduced to a very small amount. In other words, this requires use of a sampling TFT featuring a high performance. To perform the equivalent operation with the sampling TFT used in the first Embodiment, the ratio between the retention period and overwrite period should be the same as that in the first Embodiment, as described below. For example, if operations in the first Embodiment are possible in the retention period of 100 ms and the overwrite period of 100 ms, the retention period is set at 1 ms and overwrite period at 1 ms in the present Embodiment. The voltage of the sampling capacitors of all pixels should be overwritten in 100 overwrite periods. This step allows one overwriting to be performed every 200 ms in any cases, when viewed in terms of one pixel. This enables the operation using the sampling TFT of the same performance.
In the present Embodiment, a.c. voltage is not applied to the liquid crystal in the overwrite period, so effective voltage is reduced to a half. However, the same display is enabled by doubling the amplitude of the a.c. voltage applied to the opposite electrode.
The present Embodiment provides a liquid crystal display using a small-sized circuit characterized by lower power consumption, and a high speed display when display has switched.
Embodiment 5
FIG. 14 is a block diagram representing the firth Embodiment of a liquid crystal display according to the present invention.
The configuration of display unit 1 is the same as that in the first Embodiment. The signal data write circuit decodes the address data signal, and comprises a decoder circuit to select the signal electrode corresponding to the address data signal, an OR circuit 102 to issue the output of the decoder circuit output and OR signal of the reset signal 1 , and a drain signal sampling TFT 105 to sample drain signals in response to the output of the OR circuit 102 and to issue them to the signal electrode. The scanning line selection circuit comprises a shift register to produce output in response to clock signal 2 , an AND circuit 104 to produce AND signal VG′ (j) between the output of the shift register and the inversion signal of the reset signal 1 , and an OR circuit 103 to produce an OR signal between the output of the AND circuit 104 and output of the reset signal 2 .
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflector type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The following describes the operation principle of the fourth Embodiment of the liquid crystal display according to the present invention comprising N-row×M-column pixels, using the drive waveform shown in FIG. 15 . Here the display data signal voltage to write i-column by j-row pixels into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) denotes either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by four periods; reset period, write period, retention period, and overwrite period. When the display has been switched, it is driven in the order of reset period, write period, retention period, and overwrite period, retention period, overwrite period, etc. If display does not change, it is driven in the order of retention period and overwrite period repeatedly. Reset period and write period are used only when display has been switched.
Reset signal 1 and reset signal 2 go high during the reset period. In this case, the outputs of the OR circuit 102 and OR circuit 103 go high despite the state of the shift register, etc. Since the output of OR circuit 102 is of high level, the drain signal is written into all signal electrodes through drain signal sampling TFT 105 . Since the output of OR circuit 103 is at the high level, voltage of all scanning electrodes is VG(j)=VGH, and the display data signals of the signal electrodes are written into the sampling capacitor of all the pixels. The display data signal becomes VDL after having become VDH once during the reset period. So the switching TFTs of all pixels are turned off after having been turned on once. During the reset period, voltage VC of the opposite electrode is equal to voltage VCOM of the common electrode, so display electrode 7 is kept in the floating mode after voltage has become VCOM, thereby retaining voltage VCOM.
In the ensuing write period, voltage V(i, j) in response to display is written into the sampling capacitor of pixel (i ,j) while a.c. voltage is applied to the opposite electrode. In the reset period, V (i,j)=VDL is stored into all sampling capacitors, so the address of column i of the pixel where v (i, j)=VDH is written is input as an address data signal. Only the voltage of the sampling capacitor of the pixel where VDH is written is rewritten. This step reduces the write period.
In the write period, address data signals corresponding to address i of the pixel where VDH is written are input sequentially, and the signal to select the i-th signal electrode is issued from the decoder circuit. The drain signal voltage is VDH while address data signal in the j-th row is sent, and VDHs are sequentially issued into the signal electrode selected from the decoder circuit by drain signal sampling TFT 105 . The initial VDL is stored in other signal electrodes. The address data signal stops after the above operation is repeated the number of times equivalent to the number m(j) of the pixels in the jth row where VDH is written. The voltage of the signal electrode is retained for a specified time. Then the reset signal 1 goes high, and drain signals are written into all signal electrodes through drain signal sampling TFT 105 . (This period is defined as a horizontal period). In this case, the drain signal is VDL, and VDL is written into all signal electrodes. This period is defined as a horizontal period. In this case, horizontal period changes according to m(j).
In the horizontal period, the shift register of the scanning line selection circuit selects the scanning electrode in response to clock signal 2 synchronized with the horizontal period. So the high level is output to VG′ (J). Since AND signals between the inversion level of reset signal 1 and VG′ (j) are issued to the scanning electrode, VG (j)=VGH is output in the horizontal period only when the reset signal is at the low level. The sampling TFT of the pixel (i,j) where voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD (i) of the connected signal electrode, and the voltage is retained to the sampling capacitor. VG (j)=VGL in the horizontal reset period, and the connected sampling TFT is turned off.
So the VD (i) in response to display is retained without single electrode voltage VDL written into the sampling capacitor. This operation is repeated N times which correspond to the number of the scanning electrodes, and the data of display data retention circuit of all pixels are rewritten, thereby terminating the write period.
Similarly to the case of the second Embodiment, voltages all signal electrodes are forcibly set to VDL at the end of each horizontal period in the present Embodiment, so said operation error resulting from data in the previous row does not occur.
Then the operations of drain signal, address data signal, clock signal 2 , reset signal 1 and reset signal 2 are stopped, and a.c. voltage vC continues to be applied to the opposite electrode (retention period). Voltage VM retained in the sampling capacitor during this retention period varies according to the leakage of the sampling TFT and others. The length of the retention period is set to ensure that the voltage VDH written into the pixel where display is on is not less than voltage VMH throughout the retention period, and the voltage VDL written into the pixel where display is off does not exceed voltage VML throughout the retention period. Accordingly, during the retention period, the switching TFT of the pixel where display is on is in the state of connection (ON state), while the switching TFT of the pixel where display is off is in the state of non-connection (OFF state). So as shown in FIG. 15, the voltage VS of the display electrode of the pixel where display is on is equal to the voltage VCOM of the common electrode (solid line), whereas the voltage VS of the display electrode of the pixel where display is off is equal to the voltage VC of the opposite electrode (broken line). Since voltage VLC=VC−VS is applied to the liquid crystal, a.c. voltage with amplitude V0 is applied to the liquid crystal of the pixel where display is on (solid line), while voltage is not applied to the liquid crystal of the pixel where display is off (broken line).
The operation in the ensuring overwrite period is the same as that in the write period. Similarly to the second Embodiment, said operation error due to data in the previous row occurs in the overwrite period, unlike the case in the write period. However, it occurs in a very short time, without affecting display. In the overwrite period, when display data signal V (i, j)=VDH is overwritten into the sampling capacitor of the pixel in the j-th row in the j-th horizontal period, voltage VGL written to the signal electrode in the (j−1)-th horizontal reset period remains when the voltage of the j-th scanning electrode becomes VGH. Before the overwrite period, voltage not less than VMH is retained in the sampling capacitor. Immediately when the voltage of the j-th scanning electrode has become VGH, the switching TFT changes from ON to OFF state while a.c. voltage is applied to the opposite electrode. Then d.c. voltage will be applied to the liquid crystal as described above. In this case, However, V (i, j)=VDH is written immediately thereafter, the switching TFT is turned on. The d.c. voltage is applied to the liquid crystal only for a very short time, without affecting the display.
In the present Embodiment, VDH is output to the m(j) signal electrodes in the horizontal period of write period and overwrite period, wherein the number of signal electrodes corresponds to that of pixels where VDH is written. After this voltage is retained for a specified time, scanning electrode voltage is changed to VGL, and reset signal 1 is set to the high level. Immediately after VDH is issued to m(j) signal electrodes, scanning electrode voltage is changed to VGL, and the reset signal 1 is set to the high level. Operation is possible according to these steps. In this case, however, VDH is applied to m(j)-th signal electrodes only for a very short time. This requires the sampling TFT to have a high performance. If scanning electrode voltage is kept at VGH after VDH is applied to the m(j)-th signal electrode as in this Embodiment, and this state is retained for some time to prolong the time to write into the sampling capacitor, operation is possible even with the TFT of poorer performances.
As described above, use of the fifth Embodiment of the liquid crystal display according to the present invention reduces the write period and the time from appearance to disappearance of display. It also reduces power consumption.
Said second or third Embodiment almost completely eliminates the time for a new display to appear when display has switched. All the displays appear completely when display data signals V(i, j) have been written into the sampling capacitors of all pixels. So increase in the number of pixels will take a long time before all displays appear. Furthermore, a greater number of pixels means a longer write period. In the liquid crystal display according to the present invention, much time is required for writing. Increase in the number of pixels will result in increased power consumption.
By contrast, the present Embodiment provides a liquid crystal display characterized by high definition, lower power consumption, and a high speed display when display has switched.
Embodiment 6
FIG. 16 is a block diagram representing the scanning line selection circuit of the sixth Embodiment of the liquid crystal display according to the present invention. Display unit 1 formed on the TFT substrate and signal data write circuit are the same as those of the second Embodiment.
The scanning line selection circuit comprises;
(1) a shift register to produce output VG′ (j) in response to clock signal 2 ,
(2) an AND circuit 104 to produce AND signal VG′ (j) between the output VG′ (j) of the shift register and the inversion signal of the reset signal 1 , (3) an AND circuit 106 to produce output VG′ (mk+1) (m=0, 1, 2, . . .) of the (mk+1)-th shift register for each k-th and reset signal 2 , and
(4) an OR circuit 103 to output the OR signal between the output of the AND circuit 104 which is input by VG′(j) from j=mk+1 to j=(m+1) k-th rows (m=0, 1, 2, . . .), and the output of AND circuit 106 which is input by VG′ (mk+1).
Common electrodes 8 are arranged in common for each row in parallel with scanning electrodes 3 , and are connected with one another for connection of all pixels in common. Voltage VCOM is applied by the common electrode drive circuit. From the opposite electrode drive circuit, voltage VC is applied to opposite electrode 9 on the opposite substrate installed opposite to a display electrode 7 on the TFT substrate holding the liquid crystal in-between. Although not illustrated except for the opposite substrate, a phase plate and polarizing plate are arranged to constitute a reflector type liquid crystal display. In the present Embodiment, a quarter wave plate is used as a phase plate to ensure that black is displayed while voltage is applied to the liquid crystal, and white is displayed when not applied. Setting is made so that the optical axis of the phase plate and the absorption plate of the polarizing plate have an angle of 45 degrees.
The following describes the operation principle of the sixth Embodiment of the liquid crystal display according to the present invention comprising N-row×M-column pixels, using the drive waveform shown in FIG. 17 . Here the display data signal voltage to write i-column by j-row pixels into the sampling capacitor of pixel (i, j) and pixel (i, j) is defined as V (i, j), where V (i, j) denotes either voltage level VDH or VDL shown in FIG. 6 .
The liquid crystal display is driven by two periods; write period and retention period. When display has switched, it is driven in the order of write period, retention period, overwrite period, retention period, etc. If display does not change, it is driven in the order of write period and retention period repeatedly. There is not difference between the write period and overwrite period, unlike the Embodiments mentioned above. The same write period and drive waveform are applied both when display has switched to rewrite sampling capacitor voltage and when the voltage reduced by leakage is replenished.
The write period is divided into said m sub-periods, and voltage is captured into the sampling capacitors of k-row pixels in one sub-period. This sub-period is repeated m times to capture voltages into the sampling capacitors of all m×k=N rows. The sub-period consists of the periods from the first to k-th horizontal periods.
The first horizontal period comprises the reset period and data write period. Reset signal 1 and reset signal 2 go high during the reset period. Since reset signal 1 is high, the output of OR circuit 102 is high, independently of the state of the shift register of the signal data write circuit. Since the output of the OR circuit 102 is high, display data signal is into all signal electrodes through the display data sampling TFT 101 . Meanwhile, since reset signal 2 is high level, the output voltage VG (j) from j=mk+1 to j=(m+1) k-th row (m=0, 1, 2, . . .) of the scanning selection circuit is high only when the output VG′ (k+1) of shift register is high. Accordingly, display data signals written into all signal electrodes in this case are written into the sampling capacitors from mk+1st row to (m+1) k-th row. During the reset period, display data signal becomes VDL after becoming VDH. So the switching TFT of the pixels from mk+1st row to (m+1) k-th row is turned off and reset after having been turned on once.
During the reset period, the voltage VC of the opposite electrode is made equal to the voltage VCOM of the common electrode, so display electrode 7 is in the floating mode after voltage becomes VCOM, and voltage VCOM is retained. In the second Embodiment, voltages of the sampling capacitors of pixels in all rows are reset. In the present Embodiment, resetting is made in separate m-steps for every k rows, as described above.
In the ensuing data write period, voltage V(i, j) in conformity to display is written into the sampling capacitor of pixel (i, j) in the mk+1st row while a.c. voltage is applied to the opposite electrode. In this case, the switching TFT of the pixel in mk+1st row is off during the reset period, so there is no change to the OFF from ON state where d.c. voltage is applied to the liquid crystal, as described with reference to FIG. 7 .
In the data write period, the signals which select signal electrodes sequentially are output from the shift register in response to clock signal 1 . The display data signal is synchronous with clock signal 1 , and the corresponding display data signal V (i, j) is output when the specified signal electrode is selected. Consequently, display data signals VD (i) (i=1 through N) are output sequentially to the specified signal electrode by the display data signal sampling TFT 101 . VD(i′)=VDH is issued to the signal electrode connected to the pixel (i′, j) where display is on, while VD(i″)=VDL is output to the signal electrode connected to the pixel (i″, j) where display is off. (See FIG. 6 ). The data write period terminates when above operations have been repeated M times.
The second through k-th horizontal periods comprise the horizontal reset period and data write period. In the horizontal reset period, reset signal 1 goes high, and display data signals are written into all signal electrodes via the display data signal sampling TFT 101 . In this case, the display data signal is low (VDL), and the VDL is written into all signal electrodes. In the horizontal reset period, the reset signal 2 is low unlike the reset period. So voltage VG(j) of the scanning electrode=VGL. VDL written into the signal electrode is not written into the sampling capacitor. After that, display data for one row is written into the signal electrode in data write period, similarly to the case of the first horizontal period.
In the horizontal period, the shift register of the scanning line selection circuit outputs high level to the VG′(j) in order to select the scanning electrode in response to clock signal 2 synchronized with the horizontal period. (j=mk+j′, m=0, 1, 2, . . . , j′=1, 2, . . . k) Since the OR signal of the AND signal between the inversion signal of the reset signal 1 and VG′ (j), and the AND signal between output VG′ (mk+1) of the shift register and reset signal 2 is output to the scanning electrode, VG (j)=VGH is output to the scanning electrode in the j=mk+j′-th row in the reset period of the first horizontal period when the reset signal 2 is high and output VG′ of the shift register (mk+1) is high, and in the data write period of the j′-th horizontal period when reset signal 1 is low and output VG′ (mk+j′) of the shift register is high. The sampling TFT of the pixel (i, j) where the voltage VG (j) of the connected scanning electrode has become VGH captures the voltage VD(i) of the connected signal electrode, and retains the voltage in the sampling capacitor. Since VG (j)=VGL in the horizontal reset period, the connected sampling TFT is turned off and VD (i) in conformity to display is retrained, without the voltage VDL of the signal electrode being written into the sampling capacitor 11 in the horizontal reset period.
As described above, the operation error caused by data in the preceding row can be avoided by assigning the horizontal reset period where the voltages of all signal electrodes is made VDL, before VGH is output to the scanning electrode, similarly to the case of the second Embodiment.
In the retention period, the operations of clock signal 1 , display data signal, clock signal 2 , reset signal 1 , and reset signal 2 are stopped, and a.c. voltage VC continues to be applied to the opposite electrode.
Other Embodiments described above prevent the picture quality from being deteriorated by unwanted d.c. voltage applied to the liquid crystal by adopting the drive method which does not change the switching TFT from ON to OFF state, while a.c. voltage is applied to the opposite electrode. However, when d.c. voltage is applied to the liquid crystal due to some influence on the pixel where display is off, the switching TFT remains off so long as the display s off, and there is no rapid decrease in d.c. voltage applied to the liquid crystal. This may occur, for example, when the display switch has been turned on.
In the present Embodiment, the switching TFT turns on once in the write period when the voltage of the opposite electrode agrees with that of the common electrode independently of display. The pixel electrode is connected to the common electrode. Consequently, even if d.c. voltage is applied to the liquid crystal layer, it will be disappear in one write period, without raising any problem, as described above.
The drive frequency of the liquid crystal is preferred to be 60 Hz or more when flicker problems are taken into account. In the present Embodiment, the polarity of the opposite electrode voltage VC is reversed for each sub-period. So the sub-period is preferred to be 16.6 ms or less in order to drive the liquid crystal at 60 Hz or more.
The present invention provides a liquid crystal display and drive method thereof characterized lower power consumption and high speed display switching, where display is made by keeping the pixel electrode in the floating mode. It also provides a liquid crystal display with a simple circuit configuration and drive method thereof characterized lower power consumption and high speed display switching, where display is made by keeping the pixel electrode in the floating mode. | A liquid crystal display wherein display is performed based on the fact that an a.c. voltage is applied to a liquid crystal layer when a switching element establishes a connection between a display electrode and a common electrode, and the a.c. voltage is not applied to the liquid crystal layer when the switching element releases the connection between the display electrode and the common electrode. A state of the switching element changes from connection between the display electrode and the common electrode to release of the connection under a condition that respective voltages of an opposite electrode, the display electrode, and the common electrode are made substantially the same, the condition being produced by stopping an a.c. voltage applied to the opposite electrode. | 6 |
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