JP2838079B2 - Heat exchanger and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for exchanging heat by bringing a plurality of members having a large surface area into contact with a gas moving inside, and for example, a heat exchanger used as a regenerator in a pulse tube refrigerator. About.

[0002]

2. Description of the Related Art Conventionally, a heat exchanger for exchanging heat by bringing a moving gas into contact with a member having a large surface area has been known. For example, in a heat exchanger used as a regenerator of a pulse tube refrigerator, cooling has been known. The heat of the part is transferred to the outside. For example, in the pulse tube refrigerator shown in FIG. 4, as the regenerator 1, a member is packed between the pulse tube 2 and the cylinder 3 so as to increase the surface area while allowing the movement of gas (gas). In this pulse tube refrigerator, the piston 4 reciprocates in the cylinder 3 to repeatedly compress and expand the gas in the pulse tube 2 and to control the movement of the piston 4 and the compression and expansion of the gas. By providing a phase difference between them (ideally 90 °), heat is exchanged between the gas and the cooling section 2a at one end of the pulse tube 2, and the heat is similarly stored in the regenerator 1. After the exchange, the heat removed from the cooling unit 2a is transferred to the outside.

In FIG. 4, reference numeral 5 denotes an orifice, and reference numeral 6 denotes a buffer tank, which constitutes means for controlling a phase difference between movement of the piston 4 and compression / expansion of gas.

[0004]

However, in such a conventional heat exchanger, in order to efficiently perform heat exchange while allowing gas to pass through, a spherical member is packed.
Although the mesh is laminated, the members performing the heat exchange are in contact with each other in the gas moving direction. For this reason, when used in a pulse tube refrigerator, even if heat is removed from the cooling section 2a, a loss (return) due to heat conduction occurs.
Since the temperature on the opposite side is about room temperature, the effect of heat conduction loss due to contact between the heat exchange members is large, and one of the factors that hinders the improvement of the cooling capacity and cooling efficiency.
Has become one.

Therefore, the present invention reduces heat conduction loss in the direction of gas movement by eliminating heat conduction due to contact between members that come into contact with the gas moving inside, for example, in a pulse tube refrigerator. When mounted, the purpose is to improve the cooling capacity and cooling efficiency. At the same time, by providing an easy manufacturing method, without increasing the cost,
The purpose is to be able to adopt.

[0006]

In order to achieve the above object, the invention according to claim 1 is directed to a gas moving passage and a plurality of plates stacked in the passage so as to intersect the gas moving direction. A heat exchanger that allows the gas in the passage to move in the plate and forms a plurality of holes that increase the contact area with the gas, and performs heat exchange between the plate and the gas. , The plate defining a moving path
It is characterized in that it is held in contact only with the inner surface of the container, and the plates are stacked so as not to contact other plates.

According to the first aspect of the present invention, the plate is stacked in the gas passage in a non-contact manner with another plate. For example, when the plate is mounted as a regenerator in a pulse tube refrigerator, Without causing heat conduction between
Heat exchange can take place between the plate and the gas. According to a second aspect of the present invention, there is provided the method for manufacturing a heat exchanger according to the first aspect, wherein the plate is moved in a state where a sacrificial layer made of a material capable of changing a state from a solid to a fluid is sandwiched in the passage. After stacking impossible, the sacrificial layer is liquefied or vaporized and removed, and a plate is stacked in the passage in a non-contact manner.

According to the second aspect of the present invention, the plate is easily immovable by, for example, press-fitting the plate into a passage with a sacrificial layer formed of a material that can be dissolved by a solvent for etching sandwiched therebetween. After that, the sacrificial layer can be easily removed by flowing a solvent for etching into the passage to change the state of the sacrificial layer from a solid state to a liquid state, and the plates can be laminated in a non-contact manner. This sacrificial layer is not limited to a material soluble in a solvent for etching, and may be made of a material that is liquefied or vaporized by heat or the like, and is formed in advance on the entire surface or a part (edge or center) of the plate. Alternatively, a granular or powdered version of the material may be layered on a plate.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the sacrificial layer is formed by forming an ice film on the surface of the plate. According to the third aspect of the present invention, plates having a sacrificial layer formed of an ice film on the surface are immovably laminated by, for example, press-fitting into a passage, and thereafter, are left alone, heated as a whole, or heated with hot air. The sacrifice layer can be easily removed from between the plates by liquefying or evaporating the sacrifice layer by blowing (hot air) or evacuating the sacrifice layer.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 3 are views showing one embodiment of a heat exchanger manufactured by a manufacturing method according to the present invention. In this embodiment, a regenerator of a pulse tube refrigerator described in the related art using FIG. An example used as will be described.

In FIG. 1, reference numeral 1 denotes a regenerator (heat exchanger). The regenerator 1 is mounted on, for example, a pulse tube refrigerator shown in FIG. A plate 12 produced by punching a mesh into the plate is provided so as to be orthogonal to the extending direction (axial direction). Container 11
Is opened so that both ends communicate with the pulse tube 2 and the cylinder 3, and the inner diameter of the end portion 11a on the pulse tube 2 side is made smaller than the plate 12 to limit the further fitting of the plate 12. On the other hand, the piston 4 side from the end 11a is formed so as to have a smaller diameter than the diameter of the plate 12 with a minus error so as to keep the plate 12 immovable when the plate 12 is fitted.

The plate 12 is made by punching a mesh. The plate 12 is formed so as to obtain an area in contact with the gas as much as possible without excessively restricting the movement of the gas in the container (passage). The aperture ratio is set so that the position in the container 11 is not moved by the gas, and the plates 12 are stacked with a gap 13 therebetween so that the plates 12 do not contact each other. Note that the thickness of the gap 13 may be set as appropriate, and may be, for example, about the same as the plate 12.

For this reason, the pulse tube refrigerator has the piston 4
By adjusting the orifice 5 so that there is a phase difference between the compression and expansion of the gas on the pulse tube 2 side with respect to the movement in the cylinder 3, the gas in contact with the cooling unit 2a and the plate 12 expands, moves and compresses. Is repeated to transfer the heat that has been sequentially heat-exchanged to the plate 12 on the side of the piston 4 and carried out to the outside. However, since the plates 12 are individually stacked in a non-contact manner, they are received by heat conduction due to contact with each other. Does not return heat. Therefore, for example, in order to cool the superconducting material, even when the cooling part 2a is cooled to 70 K ° while the piston 4 side is at about room temperature, heat conduction between the plates 12 is not generated. That is, the heat conduction loss in the direction of gas movement is reduced,
The cooling unit 2a can be efficiently cooled to a very low temperature.

The thickness, aperture ratio, and shape of the plate 12 may be determined according to the required characteristics. For example, when the diameter of the pulse tube 2 is approximately 5 mm to 30 mm, 3
Desired characteristics can be obtained by punching out a stainless steel mesh having a thickness of about 0 μm to 50 μm and an opening ratio of about 30% to 50%. Further, the plate 12 is not limited to the mesh, and may be formed by forming a large number of holes by so-called etching in, for example, a thin stainless steel sheet material. By forming a slit having a shape and disposing the slit inside the container 11, the gas can be easily swirled between the plates 12.

Here, the regenerator 1 is provided with the piston 4 of the container 11.
By adjusting the distance for fitting the plate 12 from the side so as to be gradually reduced and press-fitting the plate 12, the plates 12 may be immovably laminated at regular intervals so as not to contact each other. Can be opened so that both sides can communicate with each other, so that a liquid or gaseous fluid can be circulated. Therefore, it is easy and easy to manufacture by any of the following first to third manufacturing methods, and the cost is increased. It won't be.

First, as a first manufacturing method, as shown in FIG. 2, a gap 13 is formed on the surface of the plate 12 with a material that can be melted by an etching solvent that does not damage the container 11 or the plate 12. A sacrificial layer 15 having a thickness of about a predetermined thickness is formed in advance, and the plate 12 is sequentially press-fitted (fitted) from the piston 4 side of the container 11 until the plate 12 abuts against the end 11a. The sacrifice layer 15 is melted by immersing the container 11
11 Remove from inside. Therefore, the sacrificial layer is pressed into the container 11 without worrying about the distance in which the plate 12 is pressed.
By simply dissolving and removing the plate 15, the plate 12 can be kept in a non-contact state at regular intervals in the container 11. In the first manufacturing method, the sacrifice layer 15 is formed on the entire surface of the plate 12, but is not limited to this. The sacrifice layer 15 may be a part of the center as shown in FIG.
For example, it may be formed as necessary, such as around, or around and center. In another embodiment of the first manufacturing method, the sacrificial layer 15 is not formed on a part of the plate 12, so that the etching solvent can quickly spread to the inside, and the manufacturing time can be reduced. it can.

Next, as a second manufacturing method, although not shown, the sacrificial layer 15 is not formed on the surface of the plate 12 but is manufactured separately from the plate 12 in a disk or ring shape. The sacrificial layer 15 when laminating
After that, work can be performed in the same manner as in the first manufacturing method. Thereby, the step of forming the sacrificial layer 15 on the surface of the plate 12 can be omitted, and the sacrificial layer 15
It is not necessary to match the inner diameter of the container 11, so only one kind or several kinds need to be prepared. In the second manufacturing method, the sacrifice layer 15 is formed in a disk or ring shape, but is not limited to this. ) May be sandwiched between the plates 12, or a powder layer (sacrifice layer) may be deposited on the plate 12 so that the thickness of the gap 13 is made. In another embodiment of the second manufacturing method, since the size and thickness of the sacrifice layer can be freely adjusted, it is not necessary to prepare the sacrifice layer 15 in advance.

Next, as a third manufacturing method, although not shown, the sacrificial layer in the first and second manufacturing methods may be formed of ice, and a part or all of the surface of the plate 12 may be formed. The sacrificial layer 15 made of an ice film may be formed, the disc-shaped or ring-shaped sacrificial layer 15 may be separately formed, or the thickness of the gap 13 may be made using granular ice. by this,
After press-fitting the plate 12 sequentially across the sacrificial layer 15 made of ice, the plate 12 may be left as it is, the container 11 itself may be immersed in warm water, or warm air may be blown into the container 11, and thereafter the vacuum container It is also possible to completely remove water by evacuating it inside.

As described above, in the present embodiment, the container 11
Only by stacking the plates 12 in a non-contact manner inside the cooling unit 2a
Can eliminate heat conduction between the plates 12 due to a temperature gradient in the regenerator 1 when heat is transferred from the regenerator 1, thereby efficiently setting the cooling unit 2a to extremely low temperatures, and Cooling capacity and cooling efficiency can be improved. Further, since the plate 12 has a simple configuration in which the layers are simply stacked in a non-contact manner, a sacrificial layer 15 made of a material or ice that can be removed by a solvent for etching is formed on the surface of the plate 12, Can be easily pressed into the plate 12,
The regenerator 1 can be manufactured at low cost.

[0020]

According to the first aspect of the present invention, since the plates are laminated in a gas passage in a non-contact manner, heat conduction between the plates due to the contact can be eliminated, and the gas is not lost due to the heat conduction. A temperature gradient can be provided in the moving direction. Therefore, for example, when mounted as a regenerator in a pulse tube refrigerator, heat can be efficiently transferred from the cooling unit to improve its cooling capacity and cooling efficiency. In addition, since the plate has a simple configuration in which the plates are simply laminated in a non-contact manner, the plate can be easily manufactured and can be adopted without increasing the cost.

For example, as in the invention described in claim 2,
A sacrificial layer made of a material that can be dissolved by a solvent for etching is previously formed on the entire surface or a part of the plate, or a layer of particles or powder made of the material is put on the plate, and the plate is pressed into the plate. After the stack is immovably laminated, the sacrificial layer can be easily removed only by pouring the etching solvent into the passage, and the passage in which the plate to be laminated in a non-contact manner can be easily fabricated. . The sacrificial layer is not limited to this, and may be any material that can change the state from a solid to a fluid (liquid, gas). For example, as in the invention according to claim 3, an ice film is formed on the surface of the plate. A sacrificial layer may be formed, in which case
The sacrificial layer can be more easily removed by leaving, heating, warm air, evacuation or the like.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a heat exchanger according to the present invention, and is a longitudinal sectional view showing a schematic overall configuration thereof.

FIG. 2 is a view showing one embodiment of a method for manufacturing a heat exchanger according to the present invention, and is a longitudinal sectional view showing a state during the manufacturing.

FIG. 3 is a view showing another embodiment of the method of manufacturing the heat exchanger according to the present invention, and is a longitudinal sectional view showing a state in the middle of the manufacturing.

FIG. 4 is a diagram showing a pulse tube refrigerator using the heat exchanger, and is a conceptual diagram showing a schematic overall configuration thereof.

[Explanation of symbols]

 Reference Signs List 1 regenerator (heat exchanger) 2 pulse tube 3 cylinder 4 piston 11 container (passage) 12 plate 13 gap 15 sacrifice layer

Claims (3)

(57) [Claims] 1. A gas moving passage, and a plurality of plates stacked in the passage so as to intersect with a moving direction of the gas, wherein the plate permits the movement of the gas in the passage and the gas. A plurality of holes for increasing a contact area with the plate, and performing heat exchange between the plate and gas, wherein the plate is in contact only with an inner surface of a container defining a moving passage.
Held, the heat exchanger, characterized in that a laminate of the plate so as not to contact the other plate. 2. The method for manufacturing a heat exchanger according to claim 1, wherein a plate is immovably laminated with a sacrificial layer made of a material capable of changing a state from a solid to a fluid in the passage. After that, the sacrificial layer is removed by liquefaction or vaporization, and a plate is laminated in the passage in a non-contact manner. 3. The method according to claim 2, wherein the sacrificial layer is formed by forming an ice film on the surface of the plate.