JP2004514095A - Ultra low temperature liquid transfer device and transfer method - Google Patents

Abstract

A method and apparatus for transferring a cryogenic fluid is disclosed. The composite, coaxial transport line has a lower pressure than the inner tube, with the first part of the cryogenic fluid flowing through the inner tube and the second part being the annulus between the inner and outer tubes. Used to flow through the annulus. The inner tube is substantially impermeable and flow control means for distributing at least a portion of the first and second portions of the cryogenic fluid to the inner tube and annulus, respectively, is provided upstream of the transport line. . In a second embodiment, the inner tube allows both gas and liquid penetration, and both the gaseous and liquid portions of the first portion penetrate into the annulus and at least one of the second portions. Form a part.

Description

[0001]
BACKGROUND OF THE INVENTION In many cases of transporting cryogenic fluids, it is important to move the fluid in as perfect a liquid state as possible. Conventionally, it has been necessary to first separate the phase of the fluid, to supercool the fluid in a heat exchanger, and to keep the line insulated by vacuum jacketing. Otherwise, heat leaks in the transport line will lead to boil-off and thus cause generally undesirable flows, such as waves, instability, pulsations, etc. in the transport line. On long transport lines, heat leakage is a particular problem.
[0002]
The present invention provides that the first portion of the cryogenic fluid flows in the inner tube, the second portion flows in the annulus between the inner and outer tubes, and the annulus in the outer tube is the inner portion. It relates to a cryogenic transfer line having a lower pressure than a tube and a coaxial or "tube-in-tube" structure. Due to this pressure difference, the liquid in the inner tube (such as boiling) can be easily cooled by the fluid in the annulus, and the liquid is kept in a saturated liquid state. It is desirable to further cool the liquid so that it can respond to heat leaks as a cooling "cushion".
[0003]
It is also important for many cryogenic fluid transfer devices that the transport line be lightweight and flexible. This provides maximum flexibility during installation, operation and maintenance, and prevents repeated bending of the line. The present invention secondly relates to a cryogenic transfer line that forms at least a portion of the line from a flexible material (such as a polymeric material).
[0004]
The prior art does not solve both of these important problems of cryogenic transfer lines.
The cryogenic transfer system of U.S. Pat. No. 3,696,627 (Longsworth) discloses the subcooling and stabilization of cryogenic flow through a rigid coaxial piping configuration. Similarly, US Pat. No. 4,296,610 (Davis), US Pat. No. 4,336,689 (Davis), US Pat. No. 4,715,187 (Stearns), and US Pat. No. 5,477,691 (White). Discloses a system.
[0005]
The non-metallic, flexible cryogenic transfer line disclosed by Chang et al. Uses cryogenic temperatures in cryogenic systems that cool cryoprobes in cryosurgery systems ("Development of high performance multi-probe cryosurgery devices"). Biomedical Instrumentation and Technology, September / October 1994 pp. 383-390. These lines needed to be short and subcooled enough to operate properly due to inherently poor heat insulation due to heat leakage boil-off due to Chang's flexible line design (−214 ° C.) needs to be filled with ultra low temperature liquid. This requires a complicated and expensive ultra-low temperature storage device and a supply and control system upstream.
[0006]
It is also known that cryogenic transfer lines are used for machining. In machining, cryogens are used as interfaces for cutting tools and workpieces. By way of example, US Pat. No. 2,635,399 (West), US Pat. No. 5,103,701 (Lundin), US Pat. No. 5,509,335 (Emerson), US Pat. No. 5,592,863 (Jaskowiak) U.S. Pat. No. 5,761,974 (Wagner) and U.S. Pat. No. 5,901,623 (Hong). Like Chang, these lines are short and require the flow of supercooled cryogenic liquid to prevent heat leak boil-off, and thus require expensive subcooling systems upstream.
[0007]
U.S. Patent No. 3,433,028 (Klee) discloses a coaxial system that carries a cryogenic fluid over a distance in a pure monolayer. The use of a sized, cryogenic conveying inner line) inlet orifice allows the liquid to pass to the outer line to evaporate if affected by external heat leaks. The flow control unit, consisting of a temperature sensor located at the exit end of the coaxial line, stops the flow of steam in the external line when the required temperature (typically 50-100 ° F) is reached. As a result, the pressure of the external line approaches the pressure of the cryogenic source. Also, the vapor in the outer line is always warmer than the liquid in the inner line. Furthermore, high heat leakage cannot be completely prevented, since the amount of liquid passing to the external line for evaporation is always limited by a non-variably provided orifice provided at the inlet. These operating principles require the use of high pressure resistant materials, non-flexible metal tubing, and heat insulating materials during line installation work.
[0008]
Japanese Patent Application Publication No. 06210105 discloses a non-ultra low temperature degassing coaxial transfer line. Due to the characteristics of the material of the tube, it is difficult to use a transfer line used at an extremely low temperature.
[0009]
SUMMARY OF THE INVENTION The present invention relates to an ultra-low temperature fluid transfer method and transfer apparatus. A coaxial transport line is used to allow a first portion of the cryogen to flow through the inner conduit, and a second portion of the cryogen to flow through the annulus between the inner and outer conduits. The pressure in the annulus is lower than the pressure in the inner conduit. In one embodiment, the inner conduit is substantially non-porous and a flow control is provided upstream of the transport line. The flow control means distributes the first portion and the second portion of the cryogenic fluid to an inner conduit and an annulus. In a second embodiment, at least a portion of the inner conduit is permeable to accommodate gas and liquid penetration of the first portion of the cryogenic fluid, and the gas and liquid portions of the first portion are annular. Permeates the body to form at least a portion of the second part.
[0010]
DETAILED DESCRIPTION OF THE INVENTION The composite, coaxial transport line of the present invention has a transport line 22 located downstream of a flow control box 20, as shown in FIG. In the transfer line 22, an outer pipe 74 is arranged around the inner pipe 72. A heat insulator 70 is provided around the outer tube 74, and a flexible protective case 68 is provided around the heat insulator 70. A first portion of the cryogenic fluid flows in the inner tube and a second portion flows in the annulus between the inner and outer tubes. The first part has a higher pressure than the second part.
[0011]
At least a portion of the transport line is formed of a flexible material, such as a composite material. It is also possible to make substantially all the inner tubes and almost all the outer tubes from a flexible composite material. Further, substantially all outer tubes are formed of a flexible composite material, and substantially all inner tubes are non-composite materials that are not brittle and flexible at ultra-low temperatures, such as, for example, (I) copper and its alloys; (ii) aluminum and its alloys; (iii) nickel and its alloys; (iv) austenitic stainless steel; (v) high-concentration graphite; and (vi) ceramic fiber braided products. It is possible. Furthermore, almost all inner tubes and almost all outer tubes are (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys (iv) austenitic stainless steel, v) It can also be formed from a flexible non-composite material selected from, for example, high-concentration graphite (vi) ceramic fiber braided tubular products. In addition, it is possible for almost all outer tubes to be formed of a flexible insulating material. Further, at least one of the inner conduit and the outer conduit may be substantially quadrilateral, polygonal, elliptical, or any other shape having a general geometric cross-section.
[0012]
The inner tube is substantially non-porous, so that the second portion of the fluid within the annulus is not a result of penetration through the inner tube. Alternatively, a plurality of holes are formed in at least a portion of the inner tube, or a plurality of holes are formed in the permeate so as to allow gas permeation and liquid permeation, and the gaseous portion and the liquid portion of the first portion are annular. And form at least a portion of the second portion. Also, portions of the inner tube, more specifically, portions that are equally spaced along the length of the inner tube, may have enhanced permeability.
[0013]
Upstream of the transport line, flow control means for distributing at least a predetermined amount of the first and second portions of the cryogenic fluid to the inner conduit and annulus, for example, a flow control box 20 shown in FIG. Have been. The flow control means is generally integrated with a means (such as a valve) for reducing the pressure of at least a portion of the second portion of the fluid distributed to the annulus. This differential pressure allows the liquid in the annulus to cool the fluid inside the inner tube. Where the inner tube is at least partially formed into permeate, penetration from the inner tube into the annulus gas complements at least a portion of the fluid distribution performed by the flow control box. The flow control box and internal components are equipped with three on / off (solenoid) valves 61, 62, 63 and a manual metering valve 64, which communicate with the flow control box via inlets to receive ultra-cold flow. Control the pressure. A key component within flow control box 20 is a three-way coupler 66, which introduces a first portion and a second portion of cryogenic fluid into the inner tube and annulus, respectively. A screw 78 connects the three-way connector 66 to the outer tube 74. The clamp member 76 is used for fixing the screw to the outer tube so as to sandwich the screw. The flow control box 20 has an insulating casing and optionally includes an insulating filter. A pressure relief valve 84 may be provided. The on / off valves 62 and 63 have openings formed in their inner walls or valve seats, and are provided with bypass orifices (86, 88).
[0014]
At least a portion of the second portion of the fluid in the annulus is transported with the liquid in the inner tube to the destination and / or to be cooled. Optionally, at least a portion of the second portion of the fluid in the annulus emanates from the point of transport and / or the object to be cooled. The former case is achieved by the use of a coaxial nozzle consisting of an inner tube communicating with the conduit inside the conveying line and an outer tube communicating with the annulus of the conveying line. In the latter case, all of the fluid in the annulus is vented. Preferably, the nozzle, which prevents the flow direction in the annulus from being the same as the flow direction of the inner tube, is provided with a heat-shrinkable connector to prevent leakage between the interface of the transfer line and the nozzle tube.
[0015]
Composite materials suitable for the transport line of the present invention include carbon-based polymers, carbon-fluorine-based polymers, copolymers and mixtures thereof, such as Teflon (trade name of EI DuPont).
[0016]
Examples of the cryogenic fluid flowing through the transfer line in the present invention include nitrogen, argon, and a mixture thereof.
The apparatus and method for transporting an ultra-low temperature fluid according to the present invention are particularly suitable for use when the transport destination or the object to be cooled has a relatively low flow rate and requires high liquid responsiveness. Examples of the transfer destination and / or cooling object in which the transfer line of the present invention is used include the following.
[0017]
(I) environmental test chambers used for stress screening electronic components (ii) shrink-fitted components (iii) specimen storage containers used for biological preservation (iv) nitrogen droplet dispensers ( v) Cryoprobe of cryosurgery system [Brief description of drawings]
FIG. 1 is a schematic diagram showing an embodiment of the present invention.

Claims (28)

A cryogenic fluid transfer line comprising an inner conduit surrounded by an outer conduit,
(A) a first portion of the cryogenic fluid flows through the inner conduit, a second portion flows through the annulus between the inner and outer conduits,
(B) the first part has a higher pressure than the second part;
(C) at least a part of the transfer line is formed of a flexible material,
(D) a transport line, wherein at least a fraction of the second portion of fluid inside the annulus is a liquid that cools the first portion of fluid inside the inner conduit. The transport line according to claim 1, wherein the outer conduit is a tube, and the inner conduit is a tube formed of a substantially non-permeable composite material. At least a portion of the inner conduit is impregnated with the gas and liquid such that both the gaseous portion and the liquid portion of the first portion penetrate into the annulus forming at least a portion of the second portion. The transfer line according to claim 1, wherein the transfer line is formed of a composite material having a property. The transport line of claim 1, wherein the inner conduit and annulus are each preceded by flow control means for distributing at least a portion of the first and second portions of the cryogenic fluid. A flow control box having (i) an inlet suitable for receiving a cryogenic fluid;
(Ii) a plurality of at least one valve disposed in the fluid path, having an inlet, receiving the flow of the cryogenic fluid and suitable for pressure regulation, being an on / off switching valve, and at least one valve being a measurement valve; And the valve
(Iii) a control box comprising: a first end disposed in a fluid path, and at least one valve connected to a second end in three directions communicating with a transport line. 5. The transport line according to claim 4, wherein: At least a small amount of the second portion of the fluid in the annulus is conveyed to the conveying destination or cooling object together with the liquid flow in the inner conduit by the action of the coaxial nozzle, and the coaxial nozzle is connected to the inner conduit. The transport line according to claim 1, further comprising an inner passage communicating with the outer ring, and an outer passage communicating with the ring. The transport line according to claim 1, wherein at least a small amount of the second portion is emitted from the target body and / or the annulus separated from the object to be cooled. The transport line according to claim 1, wherein the flexible material is selected from carbon-based polymers, carbon and mixtures thereof. The transport line according to claim 1, wherein the cryogenic fluid is selected from nitrogen, argon and mixtures thereof. An environmental test chamber wherein a transfer line is used to deliver at least a portion of the cryogenic fluid to a transfer destination and / or a cooling target, wherein the transfer destination and / or the cooling target are used for (i) a stress screening electronic component. (Ii) shrink-fitted components after contraction; (iii) specimen storage containers used for biological preservation; (iv) nitrogen droplet dispensers; (v) cutting tools used for machining. The transport line according to claim 1, wherein the workpiece (vi) comprises a cryoprobe of a cryosurgery system. An outer conduit surrounding the inner conduit, a first portion of the cryogenic fluid flowing through the inner conduit, and a second portion flowing through the annulus between the inner conduit and the outer conduit;
(A) the first part has a higher pressure than the second part,
(B) at least a part of the transfer line is formed from a flexible composite material;
(D) at least one fraction of the second portion of fluid inside the annulus cools the first portion of fluid inside the inner conduit;
Moving a cryogenic fluid using a transport line comprising: The method of claim 11, wherein the outer conduit is a tube, and the inner conduit is a tube formed of a substantially impermeable material. At least a portion of the inner conduit is permeable to gas and liquid so that both the gaseous portion and the liquid portion of the first portion penetrate into the annulus forming at least a portion of the second portion. The method according to claim 11, wherein the method is formed of a composite material having: 12. The method of claim 11, wherein the flow control means for distributing at least a portion of the first and second portions of the cryogenic fluid to each of the inner conduit and the annulus is a preceding transport line. A flow control box having (i) an inlet suitable for receiving a cryogenic fluid;
(Ii) a plurality of at least one valve disposed in the fluid path, having an inlet, receiving the flow of the cryogenic fluid and suitable for pressure regulation, being an on / off switching valve, and at least one valve being a measurement valve; And the valve
(Iii) a first end disposed in the fluid path, comprising at least one valve, and a second end connected in three directions communicating with the transport line;
15. The method of claim 14, wherein the control box comprises: The method according to claim 11, wherein at least a small amount of the second part is emitted from an annulus spaced from the point of transport and / or from the cooling object. The method according to claim 11, wherein at least a small amount of the second portion is emitted from an annulus spaced from a transfer destination and / or an object to be cooled. The method according to claim 11, wherein the flexible material is selected from carbon-based polymers, carbon and mixtures thereof. The method of claim 11, wherein the cryogenic fluid is selected from nitrogen, argon, and mixtures thereof. A transfer line used to deliver at least a portion of the cryogenic fluid to a transfer destination and / or a cooling target, wherein the transfer target and the target are (i) an environmental test chamber used for stress screening electronic components (ii). Shrink-fitted components (iii) Specimen storage containers used for biological preservation (iv) Nitrogen droplet dispensers (v) Cutting tools and / or workpieces used for machining 12. The method according to claim 11, comprising the object (vi) a cryoprobe of a cryosurgery system. The transport line according to claim 1, wherein substantially all inner conduits and substantially all outer conduits are made of a flexible composite material. Almost all outer conduits are formed of a flexible composite material, and almost all inner conduits are (i) copper or its alloy, (ii) aluminum or its alloy, (iii) nickel or its alloy. 2. The carrier of claim 1 formed from a flexible non-composite material selected from: (iv) austenitic stainless steel, (v) dense graphite (vi) ceramic fiber braided tubular products. line. The method of claim 11, wherein substantially all of the inner conduits and substantially all of the outer conduits are formed from a flexible composite material. Almost all outer conduits are formed of a flexible composite material, and almost all inner conduits are (i) copper or its alloy, (ii) aluminum or its alloy, (iii) nickel or its alloy. 12. The method of claim 11, formed from a flexible non-composite material selected from: (iv) austenitic stainless steel, (v) a high concentration of graphite, (vi) a ceramic fiber woven tubular product. 4. The transport line of claim 3, wherein the permeability of certain portions of the inner conduit along the length of the inner conduit is enhanced. 14. The method of claim 13, wherein a predetermined portion of the inner conduit has increased permeability along its length. Almost all inner conduits and almost all outer conduits are (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys (iv) austenitic stainless steel, (v) high The transport line of claim 1, wherein the line is formed from a flexible, non-composite material selected from a concentration of graphite (vi) ceramic fiber braided tubular product. Almost all outer conduits are formed of a flexible insulating material, and almost all inner conduits are (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys The transport line of claim 1, wherein the transport line is formed from a flexible, non-composite material selected from: (iv) austenitic stainless steel; (v) a high concentration of graphite; (vi) a ceramic fiber braided tubular product.