JP4242645B2 - Transport line and transport method for moving cryogenic fluid - Google Patents

Abstract

A method and apparatus are set forth for transferring a cryogenic fluid. A polymeric, coaxial transfer line is utilized where a first portion of the cryogenic fluid flows through the inner tube while a second portion flows through an annulus between the inner tube and outer tube which annulus is at a lower pressure than the inside tube. In one embodiment, the inner tube is substantially non-porous and the transfer line is preceded by a flow control means to distribute at least part of the first and second portions of the cryogenic fluid to the inner tube and annulus respectively. In a second embodiment, the inner tube is porous with respect to both gas permeation and liquid permeation such that both a gaseous part and a liquid part of the first portion permeates into the annulus to form at least a part of the second portion.

Description

[0001]
Background of the Invention In many cases of transporting cryogenic fluids, it is important to move the fluid in as complete a liquid state as possible. In the past, it was necessary to phase-separate the fluid first, to supercool it with a heat exchanger, or to keep the line in an adiabatic state by vacuum jacketing. Otherwise, heat leaks in the transfer line can result in boil-off and, in turn, cause generally undesired flows such as waves, instabilities, and pulsations in the transfer line. In long transport lines, heat leakage is a problem.
[0002]
In the present invention, the first portion of the cryogenic fluid flows through the inner tube, the second portion flows through the annulus between the inner tube and the outer tube, and the annulus in the outer tube is the inner tube. The present invention relates to an ultra-low temperature conveying line having a pressure lower than that of a tube and having a coaxial or “tube-in-tube” structure. Due to the difference in pressure, the fluid in the inner tube (such as boiling) can be easily cooled by the fluid in the annulus and can be 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]
In many ultra-low temperature fluid transfer devices, it is important that the transfer line is lightweight and flexible. This provides maximum freedom during introduction, operation and maintenance, and prevents the line from bending repeatedly. 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 polymer material ).
[0004]
The prior art has not solved both of these important problems in the cryogenic transfer line.
U.S. Pat. No. 3,696,627 (Longsworth) ultracold transport system discloses supercooling and stabilization of a cryogenic flow with a rigid coaxial piping configuration. The same applies to U.S. Pat. No. 4,296,610 (Davis), U.S. Pat. No. 4,336,689 (Davis), U.S. Pat. No. 4,715,187 (Stearns), and U.S. Pat. No. 5,477,691 (White). The system is disclosed.
[0005]
The non-metallic, flexible cryogenic transfer line disclosed by Chang et al. Uses ultra-low temperatures for cryogenic systems that cool cryoprobes in cryosurgical systems (“Development of high performance multiple probe cryosurgical devices”) Biomedical Instrumentation and Technology, September / October 1994, pages 383-390). Due to heat leak boil-off due to Chang's flexible line design, these lines need to be shortened, coupled with their inherently poor thermal insulation, and are sufficiently subcooled to operate properly (−214 ° C.) Need to be filled with ultra low temperature liquid. This requires a complex and expensive ultra-low temperature storage device, a supply device and a control system upstream.
[0006]
It is also known that ultra-low temperature transfer lines are used for machining. In machining, cryogens are used as interfaces for cutting tools and workpieces. Examples include U.S. Pat. No. 2,635,399 (West), U.S. Pat. No. 5,107,701 (Lundin), U.S. Pat. No. 5,509,335 (Emerson), U.S. Pat. No. 5,592,863 (Jaskowiac). ), US Pat. No. 5,761,974 (Wagner), US Pat. No. 5,901,623 (Hong). Like Chang, these lines are short and require a supercooled cryogenic liquid to flow to prevent heat leak boil-off, thus requiring an expensive supercooling system upstream.
[0007]
U.S. Pat. No. 3,433,028 (Klee) discloses a coaxial system that carries cryogenic fluid over a distance in a pure monolayer. By using the inlet orifice of the sized cryogenic transfer inner line , when affected by external heat leakage, the liquid is allowed to pass to the external line to evaporate. A flow control unit consisting of a temperature sensor installed at the outlet end of the coaxial line will cause the vapor in the external line to reach a temperature (usually 50-100 ° F.) that needs to be higher than the boiling point of the liquid in the internal line. Stop the flow. As a result, the pressure in the external line approaches the pressure in the cryogenic source. Also, the external line vapor is always warmer than the internal line liquid. Furthermore, the amount of liquid that passes to the external line to evaporate is always limited by a non-variably provided orifice at the inlet, so high heat leakage cannot be completely prevented. These operating principles require the use of high pressure resistant materials, inflexible metal tubing, and insulation materials during line installation work.
[0008]
Japanese Patent Application No. 06210105 discloses a non-ultra low temperature degassing polymer coaxial transport line. Due to the properties of the tube material, it is difficult to use a transfer line that is used at ultra-low temperatures.
[0009]
The present invention relates to the transport method and conveying apparatus for the cryogenic fluid. The polymer coaxial transport line is used such that the first portion of the cryogenic fluid flows through the inner conduit and the second portion of the cryogenic fluid flows 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 means is provided upstream of the transfer line. The flow control means distributes at least a portion of the first and second portions of the cryogenic fluid into the inner conduit and the annulus . In the second embodiment, at least a portion of the inner conduit is permeable to accommodate gas permeation and liquid permeation of the first portion of the cryogenic fluid, with the gas and liquid portions of the first portion being in the annulus. Permeates and constitutes at least part of the second part.
[0010]
DETAILED DESCRIPTION OF THE INVENTION The polymer coaxial conveyance line of the present invention has a conveyance line 22 disposed on the downstream side of the flow control box 20 as shown in FIG. In the transfer line 22, an outer pipe 74 is disposed around the inner pipe 72. A heat insulating material 70 is provided around the outer pipe 74, and a flexible protective case 68 is provided around the heat insulating material 70. The first part of the cryogenic fluid flows in the inner tube and the second part flows in the annulus between the inner and outer tubes. The first portion has a higher pressure than the second portion.
[0011]
At least a portion of the transport line is formed of a flexible material, such as a polymer material . It is also possible to form almost all inner tubes and almost all outer tubes from flexible polymeric materials . Furthermore, almost all outer tubes are formed of a flexible polymeric material , and almost all inner tubes are not brittle under ultra-low temperatures and are flexible non- polymeric materials , for example, (I) Copper and alloys thereof, (ii) Aluminum and alloys thereof, (iii) Nickel and alloys thereof (iv) Austenitic stainless steel, (v) High concentration graphite (vi) Ceramic fiber braided products Is possible. In addition, 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 flexible non- polymeric materials selected from high concentrations of graphite (vi) ceramic fiber braided tubular products and the like. In addition, almost all outer tubes can be formed of a flexible insulating material. Furthermore, at least one of the inner conduit and the outer conduit may have a substantially quadrilateral, polygonal, elliptical, or other general geometric cross-sectional shape.
[0012]
Inner tubes can have a substantially non-permeable, a second portion of the fluid at this end ring body is not the result of penetration through the inner tube. Or, at least a portion of the inner tube may be formed a plurality of holes, and / or can have a permeability to allow gas permeation and liquid permeation, gaseous portion of the first portion And the liquid part penetrates into the ring body and forms at least a part of the second part. Further, the plurality of portions of the inner tube, which will be described in more detail, can have their permeability enhanced by a plurality of portions arranged at equal intervals in the length direction of the inner tube.
[0013]
Effectively disposed upstream of the transfer line is a flow control means for distributing at least a portion of the first and second portions of the cryogenic fluid to the inner conduit and ring, for example, the flow control box 20 shown in FIG. Has been. The flow control means is generally integrated with means (such as a valve) for reducing the pressure of the second portion of fluid distributed to the annulus, and at least a small amount of the second portion of fluid is distributed as a liquid into the annulus. This differential pressure allows the liquid in the annulus to cool the fluid inside the inner tube. If the inner tube is at least partially permeable, permeation from the inner tube into the annulus gas can complement at least a portion of the fluid distribution performed by the flow control box. The connection and internal components of the flow control box include three on / off (solenoid) valves 61, 62, 63 and a manual metering valve 64, which communicate with the flow control box via the inlet 30 and are very cold. Accepts flow and controls pressure. The main component inside the flow control box 20 is a three-way coupler 66, which introduces a first and second portion of cryogenic fluid into the inner tube and ring respectively. A screw connection 78 connects the three-way connector 66 to the outer tube 74. An optional linear clamp member 76 can be used to secure the outer tube to the threaded connection. The flow control box 20 has a heat insulating casing and is optionally provided with a heat insulating filter. A pressure relief valve 84 may be provided. The on / off valves 62 and 63 have openings in their inner walls or valve seats, and are provided with bypass orifices (86 and 88).
[0014]
At least a small amount of the second portion of the fluid in the annulus is transported along with the liquid in the inner tube to the transport destination and / or to be cooled. Optionally, at least a small amount of the second part of the fluid in the annulus is emitted from the delivery destination and / or the object to be cooled. In the former case, this is achieved by using a coaxial nozzle comprising an inner pipe communicating with the inner conduit of the transport line and an outer pipe communicating with the ring of the transport line. In the latter case, all the fluid in the annulus will diverge, which will eliminate the restriction that the flow direction in the annulus is the same as the flow direction in the inner tube . It is desirable for any nozzle to include a heat shrink connector to prevent leakage between the transport line interface and the nozzle .
[0015]
As polymeric substances suitable for conveying line of the present invention, the carbon-based polymer over, fluorocarbon polymer - over, copolymer over and mixtures thereof, for example, Teflon (E. I. Du Pont trade name) and the like.
[0016]
Examples of the cryogenic fluid that can be transported on the transport line in the present invention include nitrogen, argon, and mixtures thereof.
The apparatus and method for transporting a cryogenic fluid in the present invention are particularly suitable for use when the transport destination and the object to be cooled have a relatively low flow rate and require high liquid responsiveness. Such transfer line of the present invention include those shown below as an example of a target site feed transportable that is used and / or cooling target.
[0017]
(I) Environmental test chambers used for stress screening electronic components (ii) Components that have been crimped after shrinking (iii) Containers for specimen storage used for biological preservation (iv) Nitrogen spray dispensers ( v) Cutting tools and / or workpieces used for machining
( Vi ) Cryoprobe of cryosurgery system [Brief description of the drawings]
FIG. 1 is a schematic diagram showing an embodiment of the present invention.

Claims (12)

An ultra-low temperature fluid transfer line, wherein the transfer line is used to deliver at least a part of the ultra-low temperature fluid to at least one of a transfer destination and a cooling target, and at least a part of the transfer line is flexible. Formed of a conductive material, the transport line is
(A) an inner conduit (72) configured to pass a first portion of the cryogenic fluid;
(B) an outer conduit (74) surrounding the inner conduit (72), the second portion of the cryogenic fluid being between the outer conduit (74) and the inner conduit (72). Compartmentalizing the passing ring;
(C) flow control means for distributing the first portion through the inner conduit (72) and distributing the second portion through the annular body;
The flow control means includes
(I) a flow path inlet (30) suitable for receiving said cryogenic fluid;
(Ii) a three-way coupler (66);
(Iii) a first flow path extending from the flow path inlet (30) to the three-way coupler (66), wherein the first flow path is connected to the inner conduit (72) by the three-way coupler (66). The first flow path has a first branch part and a first coupling part in order from the flow path inlet (30) toward the three-way coupler (66);
(Iv) A first on / off valve (63) provided in the first flow path between the first branch portion and the first connecting portion, wherein the first on / off valve (63) is a first bypass orifice (63). 86), and the first bypass orifice (86) restricts the first flow path in the closed state of the first on-off valve (63);
(V) a second flow path that branches from the first flow path at the first branch portion and extends to the three-way coupler (66), wherein the second flow path is the three-way coupler (66). The three-way coupler introduces the first part into the inner conduit, the second part into the outer conduit, and the second flow path is connected to the first branch. And having a second branch between the three-way connector (66);
(Vi) A second on / off valve (62) provided in the second flow path between the first branch portion and the second branch portion, wherein the second on / off valve (62) is a second bypass valve.
The second bypass orifice (88) restricts the second flow path in the closed state of the second on / off valve (62);
(Vii) a third flow path branched from the second flow path at the second branch portion and connected to the first flow path at the first coupling portion;
(Viii) a manual metering valve (64) provided in the third flow path;
With
Distributing the cryogenic fluid received in said first flow path from the flow path inlet (30) to said second portion and said first portion, reducing at least a portion of the pressure of said second portion, said ring body At least a small amount of the second part is distributed as a liquid in the annulus and cools the first part in the inner conduit (72), and at least a part of the second part includes the transport destination and the part. The flow of the cryogenic fluid is adjusted by adjusting the manual metering valve (64) in a closed state of the second on / off valve (62) so as to be conveyed to at least one of the objects to be cooled. Conveying line.   The transport line of claim 1, wherein the outer conduit (74) is a tube and the inner conduit (72) is a tube formed by a substantially non-permeable polymer material. At least a small amount of the second portion of the fluid in the annular body is transported to the at least one of the transport destination and the object to be cooled together with the liquid flow in the inner conduit (72) by the action of the coaxial nozzle,
The coaxial nozzle is
An inner passage communicating with the inner conduit (72);
The conveyance line according to claim 1, further comprising an outer passage communicating with the ring body.   The conveyance line according to claim 1, wherein at least a small amount of the second portion is diverged from the ring body that is separated from at least one of the conveyance destination location and the cooling target.   The transport line of claim 1, wherein the flexible material is a polymer material selected from carbon-based polymers, fluorocarbon-based polymers, copolymers, and mixtures thereof.   The transfer line of claim 1, wherein the cryogenic fluid is selected from nitrogen, argon, and mixtures thereof. At least one of the transfer destination and the cooling object is (i) an environmental test chamber used for a stress screening electronic component;
(Ii) components that have been crimped after being shrunk;
(Iii) specimen storage containers used for biological storage;
(Iv) Nitrogen splash dispenser,
The transfer line according to claim 1, selected from (v) at least one of a cutting tool and a workpiece used for machining, and (vi) a cryoprobe of a cryosurgical system.   The transport line of claim 1, wherein substantially all of the inner conduits (72) and substantially all of the outer conduits (74) are made of a flexible polymeric material. Almost all the outer conduit (74) is formed by a flexible polymeric material;
Almost all the inner conduits (72) consist of (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys, (iv) austenitic stainless steel, and (v) high-concentration graphite. The delivery line of claim 1 formed by a flexible non-polymeric material selected from (dense graphite) and (vi) a ceramic fiber braided tubular product.   Almost all the inner conduits (72) and almost all the outer conduits (74) are (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys, (iv) The delivery line of claim 1 formed from a flexible non-polymeric material selected from austenitic stainless steel, (v) high concentrations of graphite, and (vi) ceramic fiber braided tubular products. Almost all the outer conduit (74) is formed by a flexible insulating material;
Almost all the inner conduits (72) consist of (i) copper and its alloys, (ii) aluminum and its alloys, (iii) nickel and its alloys, (iv) austenitic stainless steel, and (v) high-concentration graphite. And (vi) the transfer line of claim 1 formed from a flexible non-polymeric material selected from ceramic fiber braided tubular products. A method for transporting the cryogenic fluid using the transport line according to any one of claims 1 to 11, wherein the method comprises:
Flowing the first portion through the inner conduit (72) and flowing the second portion through the annulus;
Distributing the cryogenic fluid received in said first flow path from the flow path inlet (40) to said first portion and before Symbol second portion reduces at least a portion of the pressure of said second portion, said ring At least a small amount of the second part in the body is distributed as a liquid in the annulus and cools the first part in the inner conduit (72), and at least a part of the second part is separated from the transport destination point. Adjusting the manual metering valve (64) in a closed state of the on-off valve (62) to be conveyed to at least one of the objects to be cooled .

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