Cooling system using positive displacement cryogenic liquid pump
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F17C-003/08
F17C-013/02
F04B-037/00
F04B-043/00
F04B-039/00
출원번호
US-0338501
(2008-12-18)
등록번호
US-8418480
(2013-04-16)
발명자
/ 주소
Danley, Robert L.
Traini, Patrick
출원인 / 주소
Waters Technologies Corporation
인용정보
피인용 횟수 :
1인용 특허 :
12
초록▼
A cooling system employs a single-acting positive displacement bellows pump to transfer a cryogenic liquid such as liquid nitrogen from a storage dewar to a heat exchanger coupled to a measurement chamber of an instrument, wherein cooling takes place by vaporizing the liquid. Preferably, the capacit
A cooling system employs a single-acting positive displacement bellows pump to transfer a cryogenic liquid such as liquid nitrogen from a storage dewar to a heat exchanger coupled to a measurement chamber of an instrument, wherein cooling takes place by vaporizing the liquid. Preferably, the capacity of the pump is greater than the maximum cooling requirement of the instrument, wherein both vapor resulting from vaporizing of the cryogenic liquid circulated through the heat exchanger and liquid that does not vaporize when circulated through the heat exchanger are returned to the storage dewar, wherein the vapor is subsequently vented from the dewar. Preferably, with the aid of a weir in a return line, the level of liquid in the heat exchanger is maintained full and constant, and the cooling demands are automatically met without the need for other control of the flow rate or level of the liquid. Also, unlike conventional systems, liquid transfer from the dewar does not require dewar pressurization, so that the dewar may be refilled whenever necessary without interrupting the experiment in progress.
대표청구항▼
1. A cryogenic liquid cooling system, comprising: a dewar configured to store unpressurized cryogenic liquid, said dewar comprising at least one vent portal for venting the cryogenic liquid in the dewar to the ambient atmosphere outside the dewar;a positive displacement pump configured to pump the u
1. A cryogenic liquid cooling system, comprising: a dewar configured to store unpressurized cryogenic liquid, said dewar comprising at least one vent portal for venting the cryogenic liquid in the dewar to the ambient atmosphere outside the dewar;a positive displacement pump configured to pump the unpressurized cryogenic liquid from the dewar through a transfer line without interruption when the positive displacement pump is submerged within the cryogenic liquid; anda drive assembly mechanically coupled to the positive displacement pump, wherein the drive assembly is configured to provide a reciprocating motion to the positive displacement pump, and wherein the drive assembly is configured to attach to the dewar, whereby the drive assembly is disposed outside the dewar during operation of the positive displacement pump;a heat exchanger comprising an annular cavity for receiving the cryogenic liquid;a sample stage of a scientific instrument coupled to the heat exchanger by being mounted on a mounting surface in a central cavity of the heat exchanger, said heat exchanger configured to:receive the cryogenic liquid pumped through the transfer line into the annular cavity; transfer heat away from the mounting surface and thus from the sample stage of the scientific instrument, wherein heat is transferred away from the mounting surface and thus from the sample stage of the scientific instrument by vaporization of the cryogenic liquid within the annular cavity in the heat exchanger; wherein the positive displacement pump operates to supply a continuous flow of cryogen to the heat exchanger that is sufficient to compensate for a maximum heat load applied to the heat exchanger by the sample stage andreturn unvaporized cryogenic liquid and vapor evolved from the cryogenic liquid to the dewar,wherein the at least one portal remains open to the atmosphere to allow excess cryogen vapor to vent to the outside atmosphere during operation of the pump; wherein the heat exchanger includes an exhaust tube configured such that a level of cryogenic liquid in the heat exchanger during operation corresponds an elevation of the exhaust tube. 2. The cooling system of claim 1, wherein the cooling system is configured to supply the cryogenic liquid to the heat exchanger at a flow rate that is sufficient to keep cryogenic liquid at a full level in the heat exchanger. 3. The cooling system of claim 1, wherein the positive displacement pump comprises: a bellows;an inlet head containing an inlet port configured to receive liquid into the pump when the bellows is extended; andan outlet head containing a discharge port coupled to the transfer line and configured to discharge cryogenic liquid from the pump when the bellows is compressed,wherein the inlet port is configured to close when the bellows is compressed, and wherein the discharge port is configured to close when the bellows is extended. 4. The cooling system of claim 3, wherein the inlet port is a suction check valve assembly and the discharge port is a discharge check valve assembly. 5. The cooling system of claim 3, wherein the outlet head and inlet head comprise stainless steel, and the bellows comprises nickel. 6. The cooling system of claim 1, wherein the drive assembly is configured to attach to a cover of the dewar, whereby the drive assembly is disposed outside the dewar during operation of the positive displacement pump. 7. The cooling system of claim 1, wherein the drive assembly comprises: a motor affixed to a mounting plate;an eccentric mounted to an output shaft of the motor; an antifriction bearing mounted on the eccentric and configured to engage a crosshead;a pair of drive rods substantially parallel to each other, the drive rods each affixed to the crosshead on respective upper ends, and each affixed to the positive displacement pump inlet head on respective lower ends,wherein, when the motor is energized, the antifriction bearing rotates eccentrically on the motor output shaft, wherein a reciprocating motion is imparted to the crosshead and thereby to the drive rods and to the positive displacement pump along a direction parallel to the drive rods. 8. The cooling system of claim 7, further comprising a pair of shafts affixed to the mounting plate, the shafts being parallel to the pair of drive rods, wherein the crosshead is constrained to move parallel to an axis of the drive rods,wherein the antifriction bearing is configured to engage a slot in the crosshead, and wherein the motor is a gear motor. 9. The cooling system of claim 1, wherein the cryogenic liquid is liquid nitrogen. 10. A cryogenic liquid cooling system for providing continuous cooling to a sample stage of a scientific instrument, comprising: a dewar configured to store unpressurized cryogenic liquid, said dewar comprising at least one vent portal for venting the cryogenic liquid in the dewar to the atmosphere;a positive displacement pump configured to pump the cryogenic liquid stored in a storage dewar through a transfer line as a continuous flow as long as the positive displacement pump is submerged within the cryogenic liquid; anda heat exchanger comprising an annular cavity, and a central cavity wherein a mounting surface in the central cavity is thermally coupled to the sample stage of the scientific instrument and the heat exchanger is configured to: receive the cryogenic liquid pumped from the transfer line; transfer heat from the sample stage coupled to the mounting surface by vaporization of the cryogenic liquid within the annular cavity; and return unvaporized cryogenic liquid and vapor evolved in the annular cavity from the cryogenic liquid to the dewar;wherein the at least one vent portal remains open to the atmosphere to allow excess vapor to vent to the outside atmosphere during operation of the pump;wherein cryogenic liquid is returned to the dewar through a discharge tube at all points of the pump's cycle; and a weir disposed in the discharge tube, wherein a level of the cryogenic liquid in the annular cavity during operation of the positive displacement pump corresponds to a height of the weir. 11. The cryogenic liquid cooling system of claim 10, wherein the cryogenic liquid cooling system is configured to supply the cryogenic liquid to the heat exchanger at a flow rate at least sufficient to balance a maximum heat load supplied by the sample stage. 12. The cryogenic cooling system of claim 11, wherein the wherein the positive displacement pump comprises: a bellows;an inlet head containing a suction check valve assembly configured to receive liquid into the pump when the bellows is extended; andan outlet head containing a discharge check valve assembly coupled to the transfer line and configured to discharge cryogenic liquid from the pump when the bellows is compressed,wherein the suction check valve assembly is configured to close when the bellows is compressed, and wherein the discharge check valve assembly is configured to close when the bellows is extended. 13. The cryogenic liquid cooling system of claim 10, further comprising a drive assembly mechanically coupled to the positive displacement pump, wherein the drive assembly is configured to provide a reciprocating motion to the positive displacement pump, andwherein the drive assembly is configured to attach to a cover outside the dewar during operation of the positive displacement pump. 14. The cryogenic cooling system of claim 10, wherein the cryogenic liquid is liquid nitrogen. 15. A cryogenic liquid cooling system for cooling a sample stage of a scientific instrument, comprising: a dewar configured to store a cryogenic liquid;a positive displacement pump configured to pump the cryogenic liquid in the dewar through a transfer line as a continuous flow as long as the positive displacement pump is submerged within the cryogenic liquid; anda drive assembly mechanically coupled to the positive displacement pump, configured to introduce a reciprocating motion into the positive displacement pump, and configured to mount to a cover on an outside of the storage dewar, said cover comprising at least one vent portal for venting the liquid nitrogen in the dewar to the atmosphere;a heat exchanger comprising an annular cavity for receiving cryogenic liquid and a central cavity with a mounting surface; andwherein the mounting surface is thermally coupled to the sample stage of the scientific instrument and the annular cavity is configured to receive cryogenic liquid from the transfer line and maintain a predetermined level of cryogenic liquid during operation of the positive displacement pump, said heat exchanger transferring heat by vaporization of the cryogenic liquid within the annular cavity in the heat exchanger,wherein the pump is configured to supply an excessive flow of cryogenic liquid to the cavity in the heat exchanger, such that a continuous flow of liquid is returned to the dewar after passing through the heat exchanger. 16. The cryogenic liquid cooling system of claim 15, wherein the cryogenic liquid comprises liquid nitrogen. 17. The cryogenic liquid system of claim 15, wherein the heat exchanger is configured to return unvaporized liquid and vapor evolved from the cryogenic liquid to the dewar. 18. The cryogenic liquid system of claim 15, wherein the positive displacement pump comprises: a bellows; an inlet head containing a suction check valve assembly configured to receive liquid into the pump when the bellows is extended; and an outlet head containing a discharge check valve assembly coupled to the transfer line and configured to discharge cryogenic liquid from the pump when the bellows is compressed, wherein the suction check valve assembly is configured to close when the bellows is compressed, and wherein the discharge check valve assembly is configured to close when the bellows is extended. 19. The cryogenic liquid cooling system of claim 15, wherein the drive assembly comprises: a motor affixed to a mounting plate; an eccentric mounted to an output shaft of the motor; an antifriction bearing mounted on the eccentric and configured to engage a crosshead; a pair of drive rods substantially parallel to each other, the drive rods each affixed to the crosshead on respective upper ends, and each affixed to the positive displacement pump inlet head on respective lower ends, wherein, when the motor is energized, the antifriction bearing rotates eccentrically on the motor output shaft, wherein a reciprocating motion is imparted to the crosshead and thereby to the drive rods and to the positive displacement pump along a direction parallel to the drive rods. 20. A cryogenic liquid cooling system, comprising: a dewar configured to store unpressurized cryogenic liquid, said dewar comprising at least one vent portal for venting the liquid nitrogen in the dewar to the atmosphere;a positive displacement pump configured to pump the unpressurized cryogenic liquid from the dewar through a transfer line without interruption when the positive displacement pump is submerged within the cryogenic liquid,wherein the positive displacement pump comprises: a bellows;an inlet head containing an inlet port configured to receive liquid into the pump when the bellows is extended; andan outlet head containing a discharge port coupled to the transfer line and configured to discharge cryogenic liquid from the pump when the bellows is compressed,wherein the inlet port is configured to close when the bellows is compressed, and wherein the discharge port is configured to close when the bellows is extended;a drive assembly mechanically coupled to the positive displacement pump, wherein the drive assembly is configured to provide a reciprocating motion to the positive displacement pump;a heat exchanger comprising an annular cavity for receiving cryogenic liquid, and a central cavity with a mounting surfacewherein said mounting surface is thermally coupled to the sample stage of the scientific instrument and the annular cavity is configured to receive cryogenic liquid from the transfer line and maintain a predetermined level of cryogenic liquid during operation of the positive displacement pump, said heat exchanger transferring heat by vaporization of the cryogenic liquid within the annular cavity in the heat exchanger, said positive displacement pump supplying a continuous flow of cryogenic liquid to the heat exchanger; and said annular cavity has a discharge tube conveying a continuous flow of liquid cryogen to the dewar. 21. The cooling system of claim 20, wherein the drive assembly is configured to attach to the dewar, whereby the drive assembly is disposed outside the dewar during operation of the positive displacement pump. 22. The cooling system of claim 20, wherein the inlet port is a suction check valve assembly that comprises: a suction port configured to pass liquid into the pump when the bellows is extended;a check ball configured to reversibly cover the suction port, wherein during extension of the bellows the check ball is displaced from the suction port; anda check ball retainer configured to limit motion of the check ball, wherein when the bellows is compressed the check ball closes the suction port, wherein the discharge port is a discharge check valve assembly that comprises:a discharge port configured to pass liquid from the pump when the bellows is compressed;a second check ball configured to reversibly cover the discharge port, wherein during compression of the bellows the second check ball is displaced from the discharge port;a second check ball retainer configured to limit motion of the second check ball, wherein when the bellows is extended the second check ball closes the discharge port.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (12)
Achermann Heinz (Uster CH), Apparatus for thermoanalytical investigations.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.