JPH0362999B2 - - Google Patents

Abstract

PURPOSE:To keep the heat transfer efficiency of the titled heat exchanger in a favorable condition by a method wherein the formation of a gas between a sealing and a vessel at an extremely low temperature is prevented by the force of a backup spring. CONSTITUTION:A backup spring 19 is fitted between a seal ring 18 and the bottom of a groove 20 for the seal ring 18 so as to thrust the seal ring 18 constantly against the inner wall of a tubular section 10 of the vessel. In other words, when the temperature of a laminated member 9 becomes extremely low and the seal ring 18 contracts so that a gap is produced between the inner wall of the tubular section 10 and the seal ring 18, the seal ring 18 is expanded by the force of the backup spring 19 and thrusted constantly against the inner wall of the tubular section 10. As a consequence, a low temperature gas does not bypass through the gap between the laminated member 9 and the tubular section 10 of the vessel and the backup spring 19 performs a compensatory function with respect to the low temperature contraction of the seal ring 18.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated heat exchanger, and particularly to a laminated heat exchanger suitable for cryogenic generation devices such as helium refrigerators.

One of the required functions for heat exchangers applied to cryogenic generation devices (eg, air separation devices, helium refrigerators) is compactness. In order to make the heat exchanger compact, the quickest way is to increase the heat transfer area per unit volume of the heat exchanger, and as one specific measure, various laminated heat exchangers have been proposed.

The basic form of a laminated heat exchanger is a metal heat transfer plate (perforated plate or screen) with good thermal conductivity and a spacer (plastic) with relatively poor thermal conductivity to partition the fluid passage into high temperature and low temperature sides. Or resin-impregnated paper) are generally laminated and bonded alternately.

On the other hand, the heat exchanger in a cryogenic generator is usually placed in a vacuum-insulated cold box, so there is no tolerance for leakage of the working fluid flowing through the laminated heat exchanger, even in the slightest. This is common. Although many prototypes of laminated heat exchangers have been announced, the reason why they have not been applied to actual products is that when applied to cryogenic generators,
If even the slightest crack occurs in the adhesive layer between the heat exchanger plate and the spacer as the temperature changes from room temperature to extremely low temperatures over a long period of time, the working fluid will leak from there, and the leakage will cause damage to the laminated layers. This is because gas that does not contribute to heat exchange is generated in the cold box, reducing heat exchange efficiency.Also, leaking gas may cause heat to enter the heat exchanger and other equipment housed in the cold box. This is because the generation equipment cannot operate normally at extremely low temperatures.

An object of the present invention is to provide a laminated heat exchanger that can prevent a decrease in heat exchange efficiency and a decrease in the degree of vacuum in a vacuum atmosphere. A laminate in which heat exchanger plates and spacers are alternately stacked and a header is provided at the inlet and outlet end of the working fluid,
A space is maintained in a sealed container between the header and both end portions of the container, and one supply/discharge pipe for the working fluid is connected to the container by communicating with the space, and the end portion is connected to the space. At least one of the other supply and discharge pipes for the working fluid connected to the container is connected to the header via a telescoping means, and a space is formed in the space from which one of the working fluids is discharged. One of the sealing members for the working fluid is slidably disposed between a side surface of the header and an inner wall surface of the container.

An embodiment of the present invention will be described with reference to FIG.

1 is a metal heat transfer plate (perforated plate or screen), 2 is a plastic spacer, and 3 is a high-temperature working fluid constituted by alternately stacking the heat transfer plate 1 and the spacer 2, e.g. , the high-temperature gas flow path 4 through which the high-temperature gas flows is also a low-temperature working fluid, for example, a low-temperature gas flow path through which low-temperature gas flows;
5 and 6 are headers, 7 and 8 are high-temperature gas pipes, 9 is a laminate constituted by a heat exchanger plate 1 and a spacer 2, 10 is a container cylinder portion for housing the laminate 9, 11,
12 is the end of the container, 13 and 14 are low temperature gas pipes connected to the end of the container, and 15 and 16 are headers 5 and 6.
17 is a hole for relaxing the thermal stress of the piping since the laminate 9 contracts when the temperature becomes low; 18 is a gap between the laminate 9 and the container cylindrical portion 10; , a seal ring to prevent cold gas from bypassing.

Next, to explain the operation of this laminated heat exchanger, high temperature gas is supplied from one high temperature gas pipe 7, and passes through the bellows 17, header 5, high temperature gas passage 3, header 6, and high temperature gas pipe 8 on the other side. and then sent to the next device. In addition, the low temperature gas pipe 14
The cold gas is supplied from the header 6 to the space formed by the header 6 and the container end 12, and the low temperature gas flow hole 1 of the header 6
6. The low temperature gas flow path 4, the low temperature gas flow hole 15 of the header 5, the space between the header 5 and the container end 11, and the other low temperature gas pipe 13 are sent to the next device. In such a laminated heat exchanger, heat is transferred from high-temperature gas flowing through high-temperature gas flow path 3 to heat exchanger plate 1, and from low-temperature gas flowing oppositely through heat exchanger plate 1 to low-temperature gas flow path 4. transferred to the gas.

In this example, the laminate is provided in the container so that it can expand and contract in the direction of flow of low-temperature gas and high-temperature gas using bellows, so even if the laminate is repeatedly subjected to temperature changes from room temperature to extremely low temperatures, cracks will not occur in the laminate. It is possible to prevent leakage of low-temperature gas, etc. from the laminate. Therefore, it is possible to prevent a decrease in heat exchange efficiency due to this. In addition, in this case, due to the structure, some of the low-temperature gas enters between the header 6, the laminate 9, the header 5, and the container cylindrical portion 10, passes between the header 5 and the container cylindrical portion 10, and reaches the header 5. Although an attempt is made to bypass the space formed by the container end 11,
This bypass is prevented by the seal ring 18 and contributes to heat exchange in the laminate 9, so
A decrease in heat exchange efficiency can be prevented. Furthermore, even if gas leaks from the laminate for some reason, the leakage of the leaked gas into the cold box can be prevented by the container, and bypassing of the leaked gas can be prevented by the seal ring.

In the above embodiment, when a laminated heat exchanger using a container made of metal as a container and a seal ring made of a polymeric material as a seal ring is applied to a cryogenic generator, In this case, since the radial contraction of the seal ring made of a polymeric material is larger than the radial contraction of the container made of metal, a gap is created between the seal ring and the container, and therefore, Part of the low temperature gas leaks from the layered bodies of the stacked body and bypasses through the gap, and also bypasses through the gap without passing through the low temperature gas flow path. This bypassed leakage gas and low-temperature gas do not contribute to heat exchange, resulting in problems such as a decrease in the efficiency of the stacked heat exchanger.

An embodiment that can solve such problems will be described next.

A second embodiment of the present invention will be explained with reference to FIG. Note that in FIG. 2, parts that are the same as those in FIG.

Reference numeral 19 denotes a back-up spring made of metal and formed into an annular shape. The back-up spring 19 is interposed between the seal ring 18 and the bottom surface of the seal ring groove 20, and always applies a spring force to the seal ring 18 against the inner wall of the container cylindrical portion 10. It has the role of pushing. That is, according to this embodiment, when the laminate 9 becomes extremely low temperature and the seal ring 18 contracts and a gap is created between it and the inner wall of the container cylindrical portion 10, the spring force of the back-up spring 19 causes the seal ring 18 to contract. The laminate 9 is always pressed against the inner wall of the container cylindrical portion 10.
The leaked gas and low-temperature gas will no longer bypass through the gap between the stacked body 9 and the container cylindrical portion 10, and a decrease in efficiency of the heat exchanger can be prevented. The width of the back-up spring 19 is preferably narrower than the width of the seal ring groove 20 with some margin. Thereby, it is possible to prevent the backup spring 19 from being trapped in the seal ring groove 20 in the form of a cold fit due to the difference in the amount of contraction due to the difference in linear expansion coefficient between the header 5 and the backup spring 19.

A third embodiment of the present invention will be explained with reference to FIG. In FIG. 3, the backup spring 19 is divided into at least two parts in the width direction, and the seams 21 and 21' are shifted in the circumferential direction so that they are not in the same position.

According to this embodiment, leakage of gas or low-temperature gas from the laminate through the seams of the back-up springs is reduced, and by shifting the seams, there is only one part to support the seal ring. The seal ring will not be damaged by the joint.

A fourth embodiment of the present invention will be described with reference to FIG. In FIG. 4, the seal ring groove 20 is equipped with a spring-loaded seal ring having a leaf spring 22 installed inside the seal ring 18', and the seal ring 18' and the bottom of the seal ring groove 20 are connected to each other for back-up. Spring 1
9 is interposed. In this case, since the seal ring 18' with the leaf spring 22 installed therein cannot be expanded, a part of the header 5 is divided and the presser plate 23 is
In addition, a set screw 24 is required.

According to this embodiment, since the spring is doubled, the correction function for low-temperature shrinkage can be further increased.

In each of the above embodiments, a seal ring or the like is used to prevent the bypass of the working fluid, but metallurgical sealing may also be performed using welding, brazing, etc. Alternatively, the sealing may be performed using, for example, an epoxy resin, which has a coefficient of thermal expansion relatively close to that of the container member and is unlikely to cause problems such as cracking even at extremely low temperatures.

According to the present invention, it is possible to prevent a decrease in heat exchange efficiency of a laminated heat exchanger and a decrease in the degree of vacuum of a vacuum atmosphere.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a laminated heat exchanger according to an embodiment of the present invention, and FIGS. 2 to 4 are sections of a laminated heat exchanger according to second to fourth embodiments of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Heat exchanger plate, 2... Spacer, 5, 6... Header, 7, 8... High temperature gas piping, 9... Laminated body, 10... Container cylinder part, 11, 12... Container end part, 13, 14...Low temperature gas piping, 18, 18'
... Seal ring, 19 ... Backup spring, 20 ... Seal ring groove, 22 ... Leaf spring,
23... Pressing plate, 24... Set screw.

Claims (1)

[Claims] 1. A stacked body in which heat transfer plates and spacers are alternately stacked to form passages through which high-temperature working fluids and low-temperature working fluids flow, and headers are provided at the inlet and outlet ends of the working fluids. A space is provided in a sealed container between the header and both end portions of the container, one supply/discharge pipe for the working fluid is connected to the container by communicating with the space, and the end portions are connected to the container. At least one of the other supply and discharge pipes for the working fluid located in the space and connected to the container is connected to the header via a telescoping means, and one of the working fluids is discharged from the space. 1. A laminated heat exchanger characterized in that one sealing member for the working fluid is slidably disposed between a side surface of the header forming the header and an internal curved surface of the container. 2 A patent claim in which a flow path through which the low-temperature working fluid flows is formed around the flow path through which the high-temperature working fluid flows, and the low-temperature working fluid can be supplied to and discharged from the flow path through the header and the space. The laminated heat exchanger according to item 1. 3. A seal ring groove is formed on the entire circumference of a side surface of the header that forms the space from which the low-temperature working fluid is discharged, and corresponds to the inner wall surface of the container, and a seal ring is encircled in the seal ring groove. A laminated heat exchanger according to scope 2. 4. A seal ring groove is formed on the entire circumference of the side surface of the header that corresponds to the metal inner wall surface of the container of the header forming the space from which the low-temperature working fluid is discharged, and a seal ring made of a polymeric material is provided in the seal ring groove. 3. The laminated heat exchanger according to claim 2, wherein a back-up spring made of metal is interposed between the seal ring and the bottom surface of the seal ring groove. 5. Claim 4, wherein the width of the back-up spring is narrower than the width of the seal ring groove.
The laminated heat exchanger described in . 6. The laminated heat exchanger according to claim 5, wherein the backup spring is divided into at least two parts in widthwise direction, and the joints of the divided backup springs are shifted in the circumferential direction. 7. The laminated heat exchanger according to claim 3 or 4, wherein the seal ring is a spring-loaded seal ring.