JPH0552569U - Laminated heat exchanger - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention aims to improve the reliability of the spacer-header joint portion and reduce the gas leakage to improve the heat exchange performance. [Structure] This is achieved by alternately stacking porous heat transfer plates 1 and plastic spacers 2 and installing plastic headers 5 and 6 (same material as the spacers 2) at both ends thereof. [Effect] It is effective in improving the reliability of the joint and improving the heat exchange performance.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a laminated heat exchanger, and more particularly to the structure of a laminated heat exchanger suitable for a cryogenic generator such as a helium liquefier refrigerator.

[0002]

[Prior Art]

 Conventionally, as described in the literature concerning the development of laminated heat exchangers in Sumitomo Heavy Industries Tech. Vol.32, No.95, August, 1984, a porous heat transfer plate made of a high heat conductor and a low heat conductor were used. A heat exchanger structure in which a plurality of heat insulating partition plates are stacked alternately and headers are provided at both ends, and all of these are joined by an adhesive. Each material is a porous heat transfer plate made of industrial pure aluminum, and a heat insulating partition plate is made of epoxy. An example is shown in which the glass laminated plate and the header are made of the same material as the porous heat transfer plate or a metal material (analogous to the surface treatment process).

[0003]

[Problems to be solved by the device]

In the above prior art, the headers located at both ends of the laminated product formed by alternately laminating the porous heat transfer plates and the spacers are made of the same metal material as the porous heat transfer plate material. Further, structurally, the heat transfer performance, strength, and compactness make the porous heat transfer plate and spacer as thin as possible, and the header is made relatively thick due to the influence of the gas distribution flow path and the pipe connection part. The problem is the thermal stress between the spacer and the header that occurs when a temperature difference from low to very low temperature is added. That is, the relationship between the plate thickness t per unit length of the porous heat transfer plate, the spacer and the header is t _P ≈t _S << t _H (subscripts P, S and H are the multi-hole heat transfer plate, the spacer and the header, respectively). It is assumed that various quantities will be treated in the same manner), and the relationship between the Young's modulus E of the material is E _S <E _P <E _H (Even if the materials of P and H are the same, since P is porous, the effective Young's modulus is substantially effective. When the relation of linear expansion coefficient α is α _S <α _P ≈ α _H , the relation of stress between members is divided into header and spacer, porous heat transfer plate and spacer and expressed by the following equation. It However, this formula expresses the tensile stress of the low linear expansion coefficient member (spacer) when both ends are fixed by rigid bodies, although the properties of the members are different, and ΔT is the temperature difference from normal temperature to extremely low temperature. .

[0004]

[Equation 1]

[0005]

[Equation 2]

From the above equation, comparing the stress (σ _HS ) due to the combination of the header and the spacer and the stress (σ _PS ) due to the combination of the porous heat transfer plate and the spacer, the relationship of σ _HS > σ _PS is established, and the stress between the header and the spacer is It can be seen that the thermal stress of is high. Therefore, in general, in a laminated heat exchanger that supplies high-pressure / high-temperature gas and low-pressure / low-temperature gas facing each other, gas leakage between high and low, between high and outer peripheral parts, or between low and outer peripheral parts is caused by spacers and headers. It seems to occur frequently in the meantime. Further, it is necessary to apply a pressing force to the laminated body (including the header) as a means for improving the joining performance of the laminated heat exchanger. However, from the relationship between the plate thickness and Young's modulus of each member described above, comparing the member rigidity with the following formula,

[0007]

[Equation 3]

The rigidity of the header is several steps higher than that of the porous heat transfer plate and the spacer. For example, when undulations occur on the member contact surface, it is difficult to correct the undulations of the header (header (Because the perforated heat transfer plate may be deformed if a pressure is applied to correct the undulations). Therefore, gas leakage between the spacer and the header becomes a problem as in the above.

An object of the present invention is to improve the reliability of the spacer-header joint, which has problems in terms of thermal stress and rigidity, reduce gas leakage, and improve heat exchange performance.

[0010]

[Means for Solving the Problems]

 The above object is achieved by using the same header material as the spacer material.

[0011]

[Action]

For example, a porous material of aluminum heat transfer plate _{(> 99% Al: E P} = 3000kg / mm 2: α P = 2.4 × 10- 5 / ℃: t P = 0.6mm), the spacer material GFRP ( ^{_{E S = 2000kg / mm 2:}} α S = 2 × 10- 5 / ℃: t S = 0.3mm) and was, when adding the temperature difference from room temperature (3 00K) to a cryogenic temperature (77K), the spacer member The shear stress acting on σ is σ _S = 13.1 MPa (note that the value of E _{P is} a value that takes into account the decrease in rigidity due to the porous aluminum material). Further, the shear adhesive force of the thermosetting epoxy adhesive is 30 to 40 MPa, and interlayer leakage between the spacer and the porous heat transfer plate can be prevented. On the other hand, when the header material is the same GFRP as the spacer material, the thermal stress between the spacer and the header becomes zero. Further, from the viewpoint of rigidity, the header material has a rigidity that is about 1/4 lower than that of aluminum material when the thickness is the same. As a result, it is relatively easy to correct the waviness of the header.

From the above, the reliability of the spacer-header joint, which has problems in thermal stress and rigidity, is improved, gas leakage is reduced, and the heat exchange performance is improved because the header has a heat insulating structure. ..

[0013]

【Example】

 Hereinafter, a cross-sectional view of a laminated heat exchanger according to an embodiment of the present invention is shown in FIG. 1 is a multi-hole heat transfer plate made of metal, 2 is a spacer made of plastic, 3 is a high temperature gas flow path formed by alternately stacking porous heat transfer plates 1 and spacers 4, and 4 is also a low temperature The gas flow path 5 has a flow path port for distributing different kinds of fluids and a gas dispersion flow path, and is a header made of the same material as the spacer 2. 6 is a gas short path (the high temperature gas flow path 3 is not A plastic header having a groove for mounting a seal ring 6a provided to prevent the passage, and 7 is a plastic header having the same structure as the header 5, and 7 is a porous heat transfer plate 1, a spacer 2 and headers 5 and 6. A laminated body formed by adhering or joining the respective contact surfaces, 8 and 9 are high temperature gas pipes, 10 and 11 are low temperature gas pipes, and 12 is connected to the low temperature gas pipe 10, and when the laminated body 7 is thermally contracted (the laminated body 7 contracts when the temperature becomes low) A bellows for relieving the thermal stress, a container cylinder portion for accommodating the laminated body 7, a container end portion 14 to which the high temperature gas pipe 8 and the low temperature gas pipe 10 are connected, 15 a high / low temperature gas pipe 9, The end portions of the container to which 11 is connected, and 16 and 17 are high temperature gas flow ports provided in the headers 5 and 6.

Next, the operation of this laminated heat exchanger will be described. High-temperature gas is supplied from one high-temperature gas pipe 8, and the high-temperature gas flow port 16 of the header 5, the high-temperature gas flow path 3, and the header 6 It is sent to the next device through the hot gas flow port 17 and the other hot gas pipe 9. The low-temperature gas is supplied from one low-temperature gas pipe 11 so as to face the high-temperature gas, passes through the header 6, the low-temperature gas flow path 4, the header 5, the bellows 12 and the other low-temperature gas pipe 10 to the next device. Sent. In this laminated heat exchanger, heat is transferred from the low temperature gas flowing through the low temperature gas passage 4 to the porous heat transfer plate 1, flows through the porous heat transfer plate 1 into the high temperature gas flow passage 3 in opposition to the low temperature gas. Transmitted to the hot gas that is present. By repeating such a cycle, the laminate 7 is cooled and the temperature difference laminate 7 from the initial temperature shrinks. At this time, since the constituent materials of the laminated body 7 are different (differences in mechanical and thermal properties), the respective shrinkage ratios are different and thermal stress is generated between the respective members. Among them, there is a drawback that high thermal stress is generated between the headers 5 and 6 and the spacer 2.

Therefore, the present invention is to improve the reliability of the header joint portion by applying a plastic product of the same material as the spacer 2 to the headers 5 and 6 which have relatively high thermal stress. Also, due to the improvement in reliability, it is possible to mitigate gas leaks between high- and low-temperature gases, low-temperature gas leaks from low-temperature gas passages to the outside, and high-temperature gas leaks from high-temperature gas passages to the outside. Since it is made of a heat insulating structure, it also contributes to the improvement of heat exchange performance.

Next, FIG. 2 shows another embodiment of the present invention. In FIG. 2, the same parts as those in FIG. 1 are omitted from the reference numerals and explanations (the same applies to other drawings below). Reference numeral 18 is a plastic header provided with a flow passage port for distributing different kinds of fluid and a gas dispersion flow passage, and provided with a seal ring installation groove and a connection portion, and 20 is a header 18 and a pipe connection A seal ring for sealing gas between the headers 19 and a connecting bolt 21 for maintaining the sealing property of the seal ring 20. The effect is almost the same as that of the embodiment shown in FIG. 1, but is particularly effective in improving the reliability of the gas pipe and the header connecting portion.

Next, FIG. 3 shows another embodiment of the present invention. Reference numeral 22 is a header with piping, in which the low temperature gas piping and the header are made of plastic, and both are integrated. The effect is almost the same as that of the embodiment shown in FIGS. 1 and 2, but it is further effective in improving the reliability of the gas pipe and the header connecting portion.

FIG. 4 shows still another embodiment of the present invention. Reference numeral 23 is a header with a seal ring, which is provided with a ring-shaped projection on the outer periphery of the header so as to be in close contact with the container, in order to prevent a short path of gas from flowing between the container housing the header and the laminated body. The effect is almost the same as that of the embodiment of FIG. 1, but further, there is an effect that the number of parts can be reduced to prevent the short path of gas, which contributes to the cost reduction and the reliability improvement due to the reduction of the number of parts.

[0019]

[Effect of the device]

 According to the present invention, there are effects such as improvement of reliability of the joint portion and improvement of heat exchange performance, and further, there are effects such as improvement of reliability of the header and the gas pipe connecting portion and cost reduction.

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated heat exchanger showing an embodiment of the present invention.

FIG. 2 is a sectional view of the vicinity of a header showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of the vicinity of a header showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a laminated heat exchanger showing still another embodiment of the present invention.

[Explanation of symbols]

1 ... Porous heat transfer plate, 2 ... Spacer, 3 ... High temperature gas flow path, 4
... low temperature gas flow path, 5, 6, 18 ... plastic header, 7 ... laminated body, 19 ... pipe connection header, 20 ...
Seal ring, 21 ... Connection bolt, 22 ... Header with piping, 23 ... Header with seal ring.

Claims (1)

[Scope of utility model registration request] 1. A laminate comprising a heat transfer plate having a flow passage for passing a fluid and spacers for forming a fluid passage alternately laminated, a passage opening for distributing different kinds of fluid and a gas Headers having dispersion channels and located at both ends of the laminate, a container for accommodating the laminate, a bellows for relieving thermal stress due to thermal contraction of the laminate, and a header passage port connected A laminated heat exchanger comprising the above pipe, wherein the material of the header is the same as the material of the spacer.