JP2006090648A - Cold accumulator and cold accumulating type refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold accumulator and a cold accumulating type refrigerator improving the heat exchanging efficiency of the cold accumulator by relieving the ununiformity of flow velocity of refrigerant gas on the same face right-angled to the flow direction of the cold accumulator to reduce the dispersion of temperature on the low temperature side. <P>SOLUTION: The cold accumulator 4 is provided with a case 40 having the high temperature side 4H through which refrigerant gas of high temperature passes, the low temperature side 4L through which refrigerant gas of low temperature passes, and storage chambers communicating with the high temperature side 4H and the low temperature side 4L and storing cold storage materials; and the cold storage materials 4a, 4b stored in the storage chambers of the case 40. The case 40 is formed in stepped shape having at least one step part 44 between the high temperature side and the low temperature side, and a passage cross-sectional area on the relatively low temperature side is set smaller than a passage cross-sectional area on the relatively high temperature side by the step part 44. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a regenerator and a regenerative refrigerator. INDUSTRIAL APPLICABILITY The present invention can be used for a regenerator used in a regenerative refrigerator such as a Stirling refrigerator, a GM refrigerator, a pulse tube refrigerator, or the like.

  As a conventional technique, as shown in FIG. 10, a Stirling refrigerator 500 in which a regenerator 120 is incorporated is known (Patent Document 1). According to the Stirling refrigerator 500, as shown in FIG. 10, the compression unit 113a is connected in series to the regenerator 120, the heat exchanger 118, and the expansion unit 115a. The compression portion 113a is defined by the compression piston 113. The expansion portion 115a is defined by the expansion piston 115. When the drive source 111 rotates in the arrow A1 direction, the driving force of the drive source 111 is transmitted to the compression piston 113 and the expansion piston 115 through the transmission mechanisms 112 and 114 while giving a predetermined phase angle, respectively. Thus, the Stirling refrigerator 500 is realized. According to the Stirling refrigerator 500, the regenerator 120 has a conical cylinder shape whose diameter is continuously reduced along the flow direction of the refrigerant gas discharged from the compression unit 113a. The cross-sectional shape of the regenerator 120 has a circular shape.

For the regenerator 120 having the conical shape described above, the flow path cross-sectional area is set to be small on the low temperature side 120L and continuously increase toward the high temperature side 120H. As another conventional technique, a regenerator 130 shown in FIG. 11 is also known. The regenerator 130 has the same right cylindrical shape over the entire length. The regenerator 130 has a circular cross section of the flow path from the low temperature side 130L to the high temperature side 130H, and the cross section area of the flow path is set to the same value. The regenerator 130 is arranged by being filled with a metal mesh 135.
JP-A-4-288455

  The above-described regenerator 130 shown in FIG. 11 has a right cylindrical shape as described above. From the low temperature side 130L to the high temperature side 130H, the cross section of the flow path is circular and the cross section area of the flow path has the same value. Is set. For this reason, when the wire mesh 135 is used as an element of the regenerator material of the regenerator 130, the wire mesh 135 basically has the same diameter, so that the production cost of the wire mesh 135 is suppressed. Furthermore, the regenerator 130 having a right cylindrical shape has an advantage that it is easier to manufacture than the conical shape. However, according to the regenerator 130 having a straight cylindrical shape, when the diameter is increased, temperature variations are likely to occur on the same plane perpendicular to the flow direction of the refrigerant gas. In particular, in the regenerator 130, temperature variation tends to occur on the same plane perpendicular to the flow direction of the refrigerant gas from the intermediate temperature side 130M to the low temperature side 130L. That is, temperature variation is likely to occur in the radial central region and the outer peripheral region from the intermediate temperature side 130M to the low temperature side 130L of the regenerator 130. In this case, the efficiency of heat exchange of the regenerator 130 is significantly lowered, and the original performance of the refrigerator may not be sufficiently exhibited.

  The reason why the temperature variation occurs in the regenerator 130 is presumed as follows. That is, because the temperature is considerably different between the low temperature side 130L and the high temperature side 130H of the regenerator 130, the refrigerant gas density is considerably different between the low temperature side 130L and the high temperature side 130H of the regenerator 130. Here, on the low temperature side 130L of the regenerator 130, since the refrigerant gas is at a low temperature, the density of the refrigerant gas is large. Further, since the refrigerant gas is high temperature on the high temperature side 130H of the regenerator 130, the density of the refrigerant gas is small. For this reason, even if the refrigerant gas has the same flow rate, the flow volume of the refrigerant gas is large on the high temperature side 130H but small on the low temperature side 130L. For this reason, the flow velocity of the refrigerant gas flowing through the regenerator 130 generally tends to be faster on the high temperature side 130H and slower on the low temperature side 130L of the regenerator 130.

  Thus, in the low temperature side 130L of the regenerator 130 where the flow rate of the refrigerant gas is slow, the influence of the positions of the central region and the outer edge region in the radial direction of the regenerator 130 is greatly expressed. As a result, on the low temperature side 130L of the regenerator 130, there is a difference between the flow rate of the refrigerant gas flowing in the central region in the radial direction of the regenerator 130 and the flow rate of the refrigerant gas flowing in the outer peripheral region in the radial direction of the regenerator 130. growing. Therefore, in the regenerator 130 having a straight cylindrical shape, the difference in heat transfer coefficient between the regenerator material and the refrigerant gas in the central region and the outer edge region, and between the regenerator material and the refrigerant gas in the same circumferential region. The difference of the heat transfer coefficient of becomes large.

  For this reason, in the low temperature side 130L of the regenerator 130, it is speculated that the temperature difference between the radial center region and the outer edge region of the regenerator 130 increases, and the heat exchange efficiency of the regenerator 130 decreases.

  Further, since the conical regenerator 120 shown in FIG. 10 is formed so that the low temperature side 120L has a smaller inner diameter, the low temperature side 120L of the regenerator 120 is more than the case of the straight cylindrical regenerator 130. However, the difference in the flow rate of the refrigerant gas between the central region and the peripheral region in the radial direction is suppressed. Therefore, the conical regenerator 120 has an advantage that the temperature difference between the central region and the outer edge region can be reduced on the low temperature side 120L.

  However, the regenerator 120 having the conical shape described above is not always easy to manufacture as compared to the case of the regenerator 130 having a straight cylindrical shape. Furthermore, according to the conical regenerator 120, when a metal mesh is used as an element of the regenerator material, a large number of metal meshes (for example, about 300 to 3000, but not limited thereto) are laminated in the thickness direction. Therefore, the size of the outer diameter of the wire mesh must be changed one by one. For this reason, a large number of wire meshes having different outer diameter sizes must be used, resulting in a disadvantage that the production cost of the wire mesh that is an element of the regenerator material is considerably increased.

  As a measure to suppress the rise in wire mesh production costs, it is conceivable to use a spherical regenerator material assembly. However, in this case, if an attempt is made to obtain a heat transfer surface area (heat exchange area) similar to that of a wire mesh using an assembly of spherical regenerator materials used in a temperature range of approximately 300K to approximately 40K, a spherical regenerator The diameter of the material is reduced. As a result, there is a problem that the pressure loss of the refrigerant gas becomes considerably larger than that in the case of the wire mesh.

  The present invention has been made in view of the above situation, and can reduce the non-uniformity in the flow rate of the refrigerant gas on the same plane perpendicular to the flow direction of the regenerator, and the radial direction of the regenerator on the low temperature side of the regenerator It is an object of the present invention to provide a regenerator and a regenerative refrigerator that are capable of reducing the temperature difference between the central region and the outer edge region of the heat exchanger and thereby improving the heat exchange efficiency of the regenerator. .

A regenerator according to the present invention includes a case having a high temperature side through which a high temperature refrigerant gas passes, a low temperature side through which a low temperature refrigerant gas passes, a high temperature side and a low temperature side, and a storage chamber for storing a regenerator material; A regenerator used in a regenerative refrigerator, comprising a regenerator material housed in a case storage chamber,
The case is formed in a step holding shape having at least one step between the high temperature side and the low temperature side, and the flow path cross-sectional area on the relatively low temperature side is on the relatively high temperature side It is characterized by being set to be smaller than the flow path cross-sectional area.

The regenerative refrigerator according to the present invention is a regenerative refrigerator having a refrigerating system that generates a cryogenic temperature, the refrigerating system has a regenerator, and the regenerator has a high temperature side through which a high-temperature refrigerant gas passes. And a low temperature side through which a low-temperature refrigerant gas passes, a high temperature side and a low temperature side and a case having a storage chamber for storing a cold storage material, and a cold storage material stored in the storage chamber of the case,
The case is formed in a step holding shape having at least one step between the high temperature side and the low temperature side, and the flow path cross-sectional area on the relatively low temperature side is on the relatively high temperature side It is characterized by being set smaller than the flow path cross-sectional area.

  The density of the refrigerant gas is basically inversely proportional to the temperature. That is, the lower the temperature, the higher the density of the refrigerant gas, and the higher the temperature, the lower the density of the refrigerant gas. Therefore, the lower the temperature, the smaller the refrigerant gas flow volume, and the higher the temperature, the larger the refrigerant gas flow volume.

  According to the regenerator according to the present invention, the flow path cross-sectional area on the relatively low temperature side (i.e., the side where the refrigerant gas flow volume is relatively small) has the relatively high temperature side (i.e., the refrigerant). It is set smaller than the cross-sectional area of the flow path on the side where the gas flow volume is relatively large. For this reason, the difference between the flow rate of the refrigerant gas having a relatively low temperature and the flow rate of the refrigerant gas having a relatively high temperature is reduced as compared to the case of using a straight cylindrical regenerator. Can do.

  As a result, compared with the case where a straight cylindrical regenerator having a large diameter size is used, in the regenerator, the flow rate of the refrigerant gas is less likely to be uneven on the same plane perpendicular to the flow direction of the refrigerant gas. Therefore, compared to the case of using a straight cylindrical regenerator, the temperature variation in the radial direction between the central region and the outer edge region in the regenerator and the temperature variation in the circumferential direction in the same circumferential region. Less. In particular, variation in temperature between the radial central region and the outer edge region is reduced on the low temperature side of the regenerator. For this reason, the efficiency of heat exchange of the regenerator is good.

  According to the present invention, the non-uniformity in the flow velocity of the refrigerant gas on the same plane perpendicular to the flow direction of the regenerator is alleviated. Therefore, the difference in the temperature in the radial direction between the central region and the outer edge region in the radial direction of the regenerator and the difference in the temperature in the circumferential direction in the same circumferential region can be reduced. In particular, on the low temperature side of the regenerator, the temperature difference between the radial center region and the outer edge region can be reduced. Thereby, the efficiency of heat exchange of the regenerator can be improved.

  Furthermore, according to the present invention, the case is formed in a step holding shape having at least one step portion between the high temperature side and the low temperature side. When a wire mesh is used as the cold storage material, the size of the outer diameter of the wire mesh can be reduced as compared to a conical regenerator. For this reason, the manufacturing cost of the wire mesh which is a cool storage material can be reduced, and it becomes advantageous to reduce the cost of a cool storage material, and by extension, the whole cost of a cool storage device.

  According to the preferable form of this invention, a cool storage material makes a wire mesh a base material. The term “base material” means that the weight ratio accounts for 20% or more of the total weight of the regenerator material. The wire mesh may occupy 50% or more by weight of the total weight of the regenerator material. The wire mesh is a combination of wire rods so as to form a passage through which refrigerant gas passes. Compared to granular regenerators such as spheres, the wire mesh can increase the surface area of the wire mesh, that is, the area involved in the heat exchange of the wire mesh, while suppressing the pressure loss of the refrigerant gas, so that the efficiency of heat exchange in the regenerator is improved. . Therefore, if a wire mesh is used as a base material for the regenerator material, the heat transfer surface area of the wire mesh, that is, heat exchange with the refrigerant gas is reduced while reducing the pressure loss of the refrigerant gas compared to a granular regenerator material such as a sphere. There is an advantage that the surface area to be touched can be increased.

  The viscosity of the refrigerant gas increases as the temperature increases, and the viscosity of the refrigerant gas decreases as the temperature decreases. Therefore, the viscosity of the refrigerant gas is high on the high temperature side of the regenerator, and the pressure loss due to the viscosity of the refrigerant gas tends to increase. The mesh opening of the wire mesh is finer as the mesh number of the wire mesh is larger, and the mesh opening of the wire mesh is coarser as the mesh number of the wire mesh is smaller. Therefore, according to a preferred embodiment of the present invention, the number of meshes of the wire mesh disposed on the high temperature side of the case, that is, the side having a large flow path cross-sectional area, It is set smaller than the number of meshes. For this reason, the mesh opening of the wire mesh arranged on the high temperature side, that is, the side having the larger flow path cross-sectional area of the case is coarser than the mesh opening of the metal mesh arranged on the low temperature side, that is, the side having the smaller flow area of the case. Is set. Thereby, the pressure loss resulting from the viscosity of the refrigerant gas on the high temperature side is suppressed, which can contribute to the improvement of the performance of the refrigerator.

  Further, the heat transfer coefficient of the refrigerant gas generally decreases as the temperature decreases because the heat conductivity of the refrigerant gas decreases and the flow velocity decreases. In addition, a wire mesh having a large number of meshes has a larger heat transfer surface area than a wire mesh having a small number of meshes if the wire diameter of the wire mesh is the same. Even when the wire diameter of the wire mesh having a large mesh number is smaller than the wire diameter of the wire mesh having a small mesh number, the number of filled sheets is increased, so that the heat transfer surface area is larger than that of the wire mesh having a small mesh number. In this case, since the wire diameter is small, the thermal responsiveness of the wire mesh as the cold storage material is good. Therefore, according to a preferred embodiment, if a wire mesh having a large mesh number (that is, a wire mesh having a large heat transfer surface area) is arranged on the low temperature side of the regenerator, that is, on the side where the flow passage cross-sectional area of the regenerator is small, the regenerator The heat transfer area of the wire mesh on the low temperature side is ensured, and the problem that the heat transfer coefficient of the refrigerant gas decreases on the low temperature side of the regenerator can be reduced. As a result, heat transfer between the regenerator material and the refrigerant gas of the regenerator is improved, the heat exchange efficiency in the regenerator can be increased, and the performance of the refrigerator can be improved.

  By the way, the area | region which faces a step part among cases is a location where the flow-path cross-sectional area of a case changes a lot. There is a possibility that refrigerant gas stagnation occurs at a location where the flow path cross-sectional area of the case changes greatly, or in the vicinity of the location. Therefore, according to a preferred embodiment of the present invention, a distributor is provided in a region of the case facing the stepped portion or in the vicinity thereof. The distributor has a function of guiding the refrigerant gas. The distributor improves the uniformity of the refrigerant gas flow. Thereby, the element of the cool storage material accommodated in the storage chamber of the case of the regenerator is used efficiently, and the heat exchange efficiency of the regenerator is improved. Also, the pressure loss of the refrigerant gas is reduced.

  As a distributor, the form which has a some hole which guides refrigerant gas can be illustrated. Such a distributor is easy to assemble, and a plurality of holes formed in the distributor can efficiently communicate a portion having a large channel cross-sectional area and a portion having a small channel cross-sectional area. The passage of the refrigerant gas is ensured between the portion having a large flow path and the portion having a small flow path cross-sectional area. Thereby, it is possible to suppress the stagnation of the refrigerant gas in the region facing the step portion in the case or in the vicinity of the region. Moreover, the distributor can illustrate the form which has the some slit opened to an outer peripheral side so that refrigerant gas may be guided.

  The distributor includes a first distributor part and a second distributor part arranged in parallel in a direction connecting the high temperature side and the low temperature side of the regenerator, and a refrigerant is provided between the first distributor part and the second distributor part. The form in which the space which can flow in gas is formed can be illustrated. The space can function as a mixing chamber that improves the uniformity by mixing the refrigerant gas, which is advantageous for reducing the temperature unevenness of the refrigerant gas.

  The distributor can be exemplified by a configuration constituted by an aggregate of a plurality of granular members. Since the distributor is composed of an aggregate of a plurality of granular members, and the heat transfer surface area of the distributor is increased, the heat storage efficiency of the regenerator is further improved by having a function as a regenerator material. The granular member is preferably formed of a metal material. For example, a fine sphere based on a metal material such as copper, copper alloy (for example, bronze), or lead may be used. The diameter of the sphere can be, for example, 0.1 to 1 millimeter, particularly 0.2 to 0.5 millimeter, but is not limited thereto.

  The distributor can be exemplified by a form formed of a porous member having a plurality of pores through which the refrigerant gas passes. The pores are sized so that the refrigerant gas can pass through. As a porous member, the form which combined the aggregate | assembly of the granular member with sintering or the binder is illustrated. In particular, a sintered member such as a sintered metal obtained by sintering an aggregate of granular members is exemplified. In this case, since the heat transfer surface area between the sintered member having pores and the refrigerant gas is increased, the heat exchange efficiency can be increased.

  Hereinafter, Example 1 of the present invention will be described in detail with reference to FIG. FIG. 1 shows an embodiment in which a regenerator 4 having a two-stage shape is applied to a Stirling refrigerator 100. The compression space 1 of the cylinder 1a is sequentially connected to a heat exchanger 6 provided at a low temperature end of the expansion space 7 via a high temperature pipe 2, a radiator 3, a two-stage regenerator 4, and a low temperature pipe 5. It is communicated. A compression piston 10 forming the compression space 1 is connected to a drive unit (not shown) via a rod 11. The expansion piston 8 of the cylinder 8 a forming the expansion space 7 is connected to a drive unit (not shown) via a rod 9. The phase of the compression piston 10 is delayed by approximately 60 to 120 degrees with respect to the phase of the expansion piston 8. In this way, the Stirling refrigerator 100 (cold storage refrigerator) is configured. It is well known that the refrigerant gas reciprocates as the compression piston 10 and the expansion piston 8 reciprocate out of phase to generate refrigeration at a low temperature in the expansion space 7.

  As shown in FIG. 1, the case 40 of the regenerator 4 has a stepped shape, and a large-diameter first tube 41 that forms a large-diameter first accommodating chamber 41 a of the regenerator 4 and a small-diameter second tube. And a small-diameter second cylinder 42 that forms a storage chamber 42a. The first cylinder 41 has a right cylindrical shape having the same diameter D1 over the axial length direction of the first cylinder 41. The second cylinder 42 has a right cylindrical shape having the same diameter D2 over the axial length direction of the second cylinder 42. The boundary between the first cylinder 41 and the second cylinder 42 is a ring-shaped step 44. As shown in FIG. 1, the end of the large-diameter first tube 41 is a high temperature side 4H (for example, a normal temperature region) and is connected to the radiator 3. The end of the second cylinder 42 having a small diameter is a low temperature side 4L (for example, 30 to 80K), and is connected to the heat exchanger 6 through the pipe 5.

  As shown in FIG. 1, a conical surface 48 for facilitating the flow of the refrigerant gas is formed at the tip of the second tube 42 of the case 40. Further, a porous member 49 having a plurality of through holes 49 a is disposed so as to face the conical surface 48.

  The wire mesh 4a, which is an element of the cold storage material, has a large outer diameter size. The wire mesh 4a is disposed in a filled state in the large-diameter first accommodating chamber 41a of the large-diameter first cylinder 41. The outer diameter size of the wire mesh 4b which is an element of the cold storage material is set smaller than the outer diameter size of the wire mesh 4a. The plurality of wire meshes 4 b are arranged in a filled state in the small-diameter second storage chamber 42 a of the small-diameter second cylinder 42 of the regenerator 4. Since the small-diameter second storage chamber 42a is close to the expansion space 7, the step-reserved shape regenerator 4 is set so that the flow path cross-sectional area decreases stepwise as the temperature decreases. Therefore, the temperature of the wire mesh is lower in the order of the wire meshes 4a and 4b.

  As described above, the density of the refrigerant gas is basically inversely proportional to the temperature. That is, the density of the refrigerant gas increases as the temperature decreases, and the density of the refrigerant gas decreases as the temperature increases. Accordingly, the lower the temperature, the smaller the refrigerant gas flow volume, and the higher the temperature, the larger the refrigerant gas flow volume. Thus, even if the refrigerant gas has the same mass, the flow volume of the refrigerant gas differs between the low temperature side 4L and the high temperature side 4H of the regenerator 4.

  As described above, according to the prior art, according to the regenerator having a straight cylindrical shape having no step portion, the flow rate of the refrigerant gas in the central region and the outer edge region in the radial direction of the regenerator on the intermediate temperature side to the low temperature side. The difference becomes larger. Therefore, among the regenerators, the temperature variation in the radial direction between the central region and the outer edge region in the radial direction and the temperature variation in the circumferential direction in the same circumferential region occur, and the heat exchange efficiency of the regenerator is remarkably high. May decrease.

  In this regard, the regenerator 4 according to the present embodiment is set in a stepped cylindrical shape, and the flow path cross-sectional area on the low temperature side 4L in the regenerator 4 where the flow volume of the refrigerant gas becomes small is the flow volume of the refrigerant gas. Is set smaller than the flow path cross-sectional area of the high temperature side 4H. For this reason, the difference between the flow rate of the refrigerant gas on the low temperature side 4L of the regenerator 4 and the flow rate of the refrigerant gas on the high temperature side 4H can be made as small as possible. Here, it is preferable that the flow rate of the refrigerant gas on the low temperature side 4L of the regenerator 4 is approximately the same as the flow rate of the refrigerant gas on the high temperature side 4H.

  According to the regenerator 4 according to the present embodiment, the flow velocity on the same plane perpendicular to the flow direction of the refrigerant gas is unlikely to be uneven on the low temperature side 4L. That is, in the low temperature side 4L of the regenerator 4, the difference in the flow rate of the refrigerant gas between the central region and the outer edge region in the radial direction and the difference in the flow rate of the refrigerant gas in the circumferential direction in the same circumferential region are reduced. . As a result, in the regenerator 4, the temperature difference between the radial direction and the circumferential direction becomes small. In particular, the temperature variation in the radial direction and the circumferential direction is reduced from the middle temperature side to the low temperature side 4L of the regenerator 4. Therefore, the efficiency of heat exchange of the regenerator 4 is improved.

  Moreover, since the element of the above-mentioned cool storage material is the metal nets 4a and 4b, pressure loss becomes small compared with the aggregate | assembly of granular cool storage materials, such as a ball | bowl. Furthermore, since the metal meshes 4a and 4b have a larger surface area, that is, an area involved in heat exchange, compared to an aggregate of granular cold storage materials such as spheres, heat exchange efficiency is improved.

  The viscosity of the refrigerant gas increases as the temperature increases, and the viscosity of the refrigerant gas decreases as the temperature decreases. Therefore, the viscosity of the refrigerant gas is high on the high temperature side 4H of the regenerator 4, and the pressure loss due to the viscosity of the refrigerant gas tends to increase. In this regard, according to the regenerator 4 according to the present embodiment, the number of meshes of the wire mesh 4a filled in the large-diameter first cylinder 41 which is the side (the high temperature side 4H) of the case 40 having the larger flow path cross-sectional area. Ma is set to be smaller than Mb, where Ma is the number of meshes of the wire mesh filled in the second cylinder 42 having a small diameter on the side (low temperature side 4L) of the case 40 where the flow path cross-sectional area is small. Has been. Here, the smaller the mesh number, the rougher the mesh opening and the lower the pressure loss. The larger the number of meshes, the finer the mesh opening and the higher the pressure loss due to the wire mesh. Therefore, according to the present embodiment, the mesh opening of the wire mesh 4a disposed on the high temperature side 4H is set to be coarser than the mesh opening of the wire mesh 4b disposed on the low temperature side 4L, and the pressure loss caused by the wire mesh is reduced. It is supposed to be. As a result, the pressure loss due to the high viscosity of the refrigerant gas on the high temperature side 4H can be compensated. Therefore, the balance of the pressure loss between the low temperature side 4L and the high temperature side 4H of the regenerator 4 is improved, which can contribute to ensuring the refrigeration performance.

  According to the present embodiment, as shown in FIG. 1, the case 40 of the regenerator 4 has a step-holding shape, and the first cylindrical 41 and the second cylindrical 42 are substantially coaxial. Are connected to each other. Such a coaxial straight cylindrical regenerator 4 is easier to manufacture than the conical regenerator 120 shown in FIG.

  Further, according to the present embodiment, as shown in FIG. 1, a step 44 having a ring collar shape, which is a boundary region between the first cylinder 41 and the second cylinder 42 constituting the regenerator 4, is inserted with a wire mesh 4a. It is along the direction perpendicular to or substantially perpendicular to the direction (arrow Y direction). Therefore, the stepped portion 44 can function as a stopper surface when a large number of wire meshes 4a are filled in the first storage chamber 41a of the case 40. Therefore, it is advantageous for filling a large number of metal meshes 4a into the first storage chamber 41a of the case 40 with high density.

  Furthermore, according to the present embodiment, the outer diameter of the metal mesh 4a corresponds to the inner diameter of the first storage chamber 41a, and the outer diameter of the metal mesh 4b corresponds to the inner diameter of the second storage chamber 42a. For this reason, it is advantageous to fill a large number of metal meshes 4b into the second storage chamber 42a with high density. Similarly, it is advantageous to fill a large number of metal meshes 4a into the first storage chamber 41a with high density. Thereby, the filling number of the metal meshes 4a and 4b can be secured, and the heat exchange area of the metal meshes 4a and 4b can be secured.

  Moreover, according to the present Example, the 1st cylinder 41 and the 2nd cylinder 42 which comprise the regenerator 4 have comprised not a cone shape but the right cylinder shape. For this reason, the metal mesh 4b can be pushed into the second storage chamber 42a by effectively using the pushing force for pushing the metal mesh 4b into the second storage chamber 42a, which is suitable for high-density filling of the metal mesh 4b, and the heat transfer surface area by the metal mesh 4b is increased. It is advantageous to secure. Similarly, the wire mesh 4a can be pushed into the first storage chamber 41a by effectively utilizing the pushing force for pushing the wire mesh 4a into the first storage chamber 41a, which is suitable for high-density filling of the wire mesh 4a and ensures a heat transfer surface area. This is advantageous.

  In the case of the conical regenerator 120 according to the prior art, when a regenerator material such as a wire mesh is pushed into the regenerator 120 with a pushing force FE (see FIG. 10) and filled, the conical wall 121 of the regenerator 120 is filled. As a result, the pushing force FE generates the force F1 in the radial direction as a component force, so that the pushing force that pushes the regenerator material such as a wire mesh or a ball into the regenerator 120 in the axial direction thereof is reduced. Although the regenerator 4 has a step holding shape having one step portion 44, it is needless to say that a step holding shape having two step portions and a step holding shape having three step portions may be used. In addition, the refrigerator is a Stirling refrigerator in this embodiment, but any cycle may be used as long as it is a regenerative refrigerator such as a GM refrigerator or a pulse tube refrigerator.

  FIG. 2 shows a second embodiment. The present embodiment basically has the same configuration and the same function and effect as the first embodiment. Hereinafter, the description will focus on the different parts. As shown in FIG. 2, it is the Example which applied the cool storage 4B which makes a step-holding shape to the pulse tube refrigerator 200 which is a cool storage type refrigerator. A heat exchanger 26 is connected to the low temperature end 27 </ b> L of the pulse tube 27. A heat radiator 28 is connected to the high temperature end 27 </ b> H of the pulse tube 27. The heat radiator 28 is connected to the buffer tank 30 through an inertance tube 29. The refrigerant gas in the pulse tube 27 moves back and forth with respect to the buffer tank 30 via the inertance tube 29, whereby the phase of the pressure waveform of the refrigerant gas is adjusted. Therefore, the inertance tube 29 and the buffer tank 30 function as a pressure waveform phase control element that adjusts the phase of the refrigerant gas and the pressure amplitude. The inertance tube 29 and the buffer tank 30 have functions corresponding to inductance and capacitance, respectively, when the refrigeration system is considered as an electric circuit.

  As shown in FIG. 2, the case 240 of the regenerator 4 </ b> B has a stepped shape, and a large-diameter first tube 241 that forms a large-diameter first housing chamber 241 a of the regenerator 4 </ b> B and a small-diameter second cylinder 241. A small-diameter second cylinder 242 that forms the storage chamber 242a and a medium-diameter third cylinder 243 that forms the medium-diameter third storage chamber 243a are provided. A ring-shaped step 244 is formed between the first cylinder 241 and the second cylinder 243. A ring-shaped step 245 is formed between the second cylinder 242 and the third cylinder 243.

  The wire mesh 4a, which is an element of a cold storage material, has an outer diameter size set larger than that of the wire mesh 4b. The wire mesh 4a is disposed in a filled state in the large-diameter first accommodating chamber 241a of the large-diameter first cylinder 241. The wire mesh 4b, which is an element of the regenerator material, has a smaller outer diameter than the wire mesh 4a. The wire mesh 4 b is disposed in a filled state in the small-diameter second storage chamber 242 a of the small-diameter second cylinder 242 of the regenerator 4. Moreover, the outer diameter size of the metal mesh 4c which is an element of a cool storage material is set smaller than the outer diameter size of the metal mesh 4a, and larger than the outer diameter size of the metal mesh 4b. This medium-diameter wire mesh 4 c is disposed in a filled state in the medium-diameter third accommodating chamber 243 a of the medium-diameter third cylinder 243 of the regenerator 4.

  As the temperature of the wire mesh, the temperature decreases in the order of the wire meshes 4a, 4c, and 4b. In the regenerator 4B having a three-stage holding shape, the flow passage cross-sectional area is gradually reduced as the temperature decreases.

  As described above, the density of the refrigerant gas is inversely proportional to the temperature. That is, the density of the refrigerant gas increases as the hot side 24H of the regenerator 4B increases, and the flow volume increases, and the density of the refrigerant gas increases as the low temperature side 24L of the regenerator 4B decreases. According to the regenerator 4B having a stepped shape according to the present embodiment, as shown in FIG. 2, the flow path cross-sectional area of the low temperature side 24L is made smaller than the flow path cross sectional area of the high temperature side 24H. For this reason, the difference between the flow rate of the refrigerant gas on the low temperature side 24L and the flow rate of the refrigerant gas on the high temperature side 24H can be reduced. As a result, also in the regenerator 4, the flow velocity on the same plane perpendicular to the flow direction of the refrigerant gas is unlikely to be uneven. As a result, in the regenerator 4B, the temperature difference between the central region and the outer edge region in the radial direction becomes small, and the temperature difference in the circumferential direction in the same circumferential region becomes small. In particular, on the low temperature side 24L of the regenerator 4B, the temperature difference between the radial central region and the outer edge region is small, and the temperature difference in the circumferential direction in the same circumferential region is small. Therefore, the efficiency of heat exchange of the regenerator 4B becomes good.

  Further, since the elements of the cold storage material described above are the metal meshes 4a, 4b, and 4c, the surface area of the metal meshes 4a, 4b, and 4c, that is, the heat, while reducing the pressure loss of the refrigerant gas as compared with the granular cold storage material such as a sphere. The area involved in exchange can be increased, and the efficiency of heat exchange can be improved.

  Further, according to the regenerator 4B according to the present embodiment, the number of meshes of the metal mesh 4a filled in the large-diameter first tube 241 on the side of the case 240 having the larger flow path cross-sectional area (high temperature side 24H) is set to Ma. In the case 4, the mesh number of the wire mesh filled in the second cylinder 242 having a small diameter which is the side where the flow path cross-sectional area is small (the low temperature side 24L) is Mb. When the number of meshes of the wire mesh filled in the middle-diameter third cylinder 243 (medium temperature side 24 m) is Mc, the magnitude of the number of meshes is set to a relationship of Ma> Mc> Mb. In other words, the size of the mesh opening is set such that the mesh opening of the wire mesh 4a> the mesh opening of the wire mesh 4c> the mesh opening of the wire mesh 4b. As a result, in the regenerator 4B, the wire mesh 4a on the high temperature side 24H is larger than the wire mesh 4b on the low temperature side 24L with respect to the cross-sectional area of the flow path through which the refrigerant gas flows. As a result, the balance of pressure loss over the entire length of the regenerator 4 is good.

  FIG. 3 shows a regenerator 4C according to the third embodiment. This embodiment basically has the same configuration and the same function and effect as the first and second embodiments. Hereinafter, the description will focus on the different parts. As shown in FIG. 3, the case 440 of the regenerator 4C includes a large-diameter first cylinder 441 that forms a first cylindrical chamber 441a that forms the large-diameter first storage chamber 441a of the regenerator 4C, and a small-diameter second storage chamber. A small-diameter second cylinder 442 having a right cylindrical shape forming 442a and a conical third cylinder 443 forming a conical third housing chamber 443a are provided. A conical third tube 443 connects the first tube 441 and the second tube 442. A metal mesh 4a is arranged in a filled state in the first storage chamber 441a having a large diameter. Further, a metal mesh 4b is arranged in a filled state in the small-diameter second storage chamber 442a.

  A distributor 340 having a refrigerant gas guiding function is disposed in a portion where the flow path cross-sectional area of the regenerator 4C changes, that is, in the third storage chamber 443a of the third cylinder 443 having a conical shape. As shown in FIG. 3, a plurality of straight holes 340 a that guide the refrigerant gas are formed in a through state in a central region in the radial direction of the distributor 340. A plurality of holes 340b having bent portions 340c are provided in the radially outer peripheral region of the distributor 340. The bent portion 340c extends from the first storage chamber 441a having a large channel cross-sectional area toward the second storage chamber 442a having a small channel cross-sectional area. As a result, even if the conical third tube 443 exists, the flow of the refrigerant gas from the first storage chamber 441a toward the second storage chamber 442a is made as uniform as possible. Thereby, the temperature unevenness in the regenerator 4C is reduced, and in particular, the temperature unevenness on the low temperature side 44L of the regenerator 4C is reduced.

  4 and 5 show a regenerator 4D according to the fourth embodiment. This embodiment basically has the same configuration and the same function and effect as the third embodiment. Hereinafter, the description will focus on the different parts. As shown in FIG. 4, the case 440 of the regenerator 4 </ b> D includes a large-diameter first cylinder 441 that forms a first cylindrical storage chamber 441 a of the regenerator 4 and a small-diameter second storage chamber. A small-diameter second cylinder 442 having a right cylindrical shape forming 442a and a conical third cylinder 443 forming a conical third housing chamber 443a are provided. Also in this embodiment, as shown in FIG. 4, the metal mesh 4a is arranged in a filled state in the first storage chamber 441a having a large diameter. The metal mesh 4b is arranged in a filled state in the second-diameter second storage chamber 442a.

  The third cylinder 443 having a right conical shape connects the first cylinder 441 and the second cylinder 442 having a right cylindrical shape. A distributor 500 having a refrigerant gas guiding function is disposed in a portion where the flow path cross-sectional area of the regenerator 4D changes, that is, in the conical third storage chamber 443a.

  As shown in FIG. 5, the distributor 500 has a circular shape in plan view. A large number of slits 501 are formed in the radial direction in the radially outer peripheral region of the distributor 500. The slit 501 has an opening 502 on the outer peripheral side. A large number of circular holes 505 are provided in a through state in a central region in the radial direction of the distributor 500. As a result, in the regenerator 4D, the gas flow between the large-diameter first storage chamber 441a having a large channel cross-sectional area and the small-diameter second storage chamber 442a having a small channel cross-sectional area is made as uniform as possible. .

  As shown in FIG. 4, the opening 502 on the outer peripheral side of the slit 501 directly faces the inner wall surface 443 f of the conical third tube 443. For this reason, even if the refrigerant gas is stagnant due to contact with the inner wall surface 443f and tends to stagnate, the refrigerant gas can be circulated through the slit 501. Therefore, it is advantageous to reduce the stagnation of the refrigerant gas in contact with the inner wall surface 443f, and it is further advantageous to reduce temperature unevenness in the regenerator 4D. In particular, it is advantageous for reducing temperature unevenness at the low temperature end 44L of the regenerator 4D.

  FIG. 6 shows a regenerator 4E according to the fifth embodiment. The present embodiment basically has the same configuration and the same function and effect as the first and second embodiments. Hereinafter, the description will focus on the different parts. As shown in FIG. 6, the case 40 of the regenerator 4 </ b> E has a step-holding shape, and a large-diameter first tube 41 that forms a straight cylindrical shape that forms a large-diameter first storage chamber 41 a of the regenerator 4 </ b> E and And a small-diameter second cylinder 42 having a right cylindrical shape forming a small-diameter second storage chamber 42a. The first cylinder 41 has the same right cylindrical shape over the entire length of the first cylinder 41. The second cylinder 42 has the same right cylindrical shape over the entire length of the second cylinder 42. The boundary between the first cylinder 41 and the second cylinder 42 is a ring-shaped step 44.

  As shown in FIG. 6, two distributors, that is, a first distributor part 60 and a second distributor part 61, are provided in the part where the flow path cross-sectional area of the refrigerant gas changes, that is, the step part 44. Are arranged in series in the flow direction. As shown in FIG. 6, the 1st distributor part 60 is addressed and faced to the metal mesh 4a with which the larger flow-path cross-sectional area was filled. A plurality of holes 60p are formed in the first distributor portion 60 in a penetrating state. The second distributor 61 is directed to face the wire mesh 4b filled in the smaller flow path cross-sectional area. A plurality of holes 61p are formed in the second distributor portion 61 in a penetrating state. As shown in FIG. 6, the holes 60p and 61p allow the large-diameter first housing chamber 41a and the small-diameter second housing chamber 42a to communicate with each other.

  As shown in FIG. 6, a circular space 68 is provided between the first distributor unit 60 and the second distributor unit 61. The space 68 communicates with the holes 60p and 61p. The space 68 is arranged in the vicinity of the stepped portion 44 or the stepped portion 44 that is a portion of the regenerator 4E where the flow path cross-sectional area changes suddenly. The space 68 can function as a mixing chamber that improves the uniformity by mixing the refrigerant gas in order to make the unevenness of the flow of the refrigerant gas uniform. Further, the space 68 also functions to make the flow rate of the refrigerant gas as uniform as possible in the central region and the outer edge region in the radial direction. Therefore, it is advantageous for reducing temperature unevenness in the regenerator 4E. In particular, it is advantageous for reducing temperature unevenness at the low temperature end 4L of the regenerator 4E.

  FIG. 7 shows a regenerator 4F according to the sixth embodiment. The present embodiment basically has the same configuration and the same function and effect as the first and second embodiments. Hereinafter, the description will focus on the different parts. As shown in FIG. 7, the case 440 of the regenerator 4F includes a large-diameter first tube 441 that forms a straight cylindrical shape that forms a large-diameter first storage chamber 441a of the regenerator 4F, and a small-diameter second storage chamber. A small-diameter second cylinder 442 having a right cylindrical shape forming 442a and a conical third cylinder 443 forming a conical third housing chamber 443a are provided. The third cylinder 443 having a conical shape connects the first cylinder 441 and the second cylinder 442 having a right cylindrical shape.

  An assembly 701 of a plurality of granular members 700 is arranged in a portion of the regenerator 4F where the flow path cross-sectional area changes, that is, the third cylinder 443. A space between adjacent granular members 700 is a passage 704. The passage 704 has a three-dimensional mesh opening shape. The aggregate 701 of the plurality of granular members 700 serves as a distributor. Since the aggregate 701 of a large number of granular members 700 is provided, the heat transfer surface area is increased, so that the heat storage efficiency of the regenerator 4F is further improved by having a function as a cold storage material. The granular member 700 is preferably formed of a metal material. For example, a fine sphere based on a metal material such as copper, copper alloy (for example, bronze), or lead may be used.

  FIG. 8 shows a regenerator 4M according to the seventh embodiment. The present embodiment basically has the same configuration and the same function and effect as the sixth embodiment. Hereinafter, the description will focus on the different parts. As shown in FIG. 8, a sintered member 750 (porous member) formed by sintering an aggregate 701 of a large number of granular members 700 is provided. The sintered member 750 has a plurality of pores 754, and is provided in a portion of the regenerator 4M where the flow path cross-sectional area changes, that is, the third cylinder 443. The pores 754 of the sintered member 750 allow the refrigerant gas to pass through. The sintered member 750 serves as a distributor.

  FIG. 9 shows an eighth embodiment. The present embodiment basically has the same configuration and the same function and effect as the first embodiment. Hereinafter, the description will focus on the different parts. As shown in FIG. 9, the case 40 of the regenerator 4 has a stepped shape, and includes a large-diameter first tube 41 that forms a large-diameter first accommodating chamber 41 a and a small-diameter second accommodating chamber 42 a. A small-diameter second cylinder 42 to be formed. The wire mesh 4a is disposed in a filled state in the large-diameter first accommodating chamber 41a of the large-diameter first cylinder 41. The plurality of spheres 4e, which are elements of the cold storage material, are disposed in a filled state in the small-diameter second storage chamber 42a of the small-diameter second cylinder 42.

(Other)
According to the second embodiment shown in FIG. 2, the metal mesh 4b is filled in the second storage chamber 242a of the small-diameter second cylinder 242 of the case 240 of the regenerator 4B, but a spherical regenerator is used instead of the metal mesh 4b. A material may be used. In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications without departing from the scope of the invention.

  The present invention can be used for a regenerative refrigerator equipped with a regenerator.

FIG. 4 is a circuit diagram according to the first embodiment in which a two-stage regenerator is applied to a Stirling refrigerator. FIG. 6 is a circuit diagram according to Example 2 in which a three-stage regenerator is applied to a pulse tube refrigerator. FIG. 10 is a cross-sectional view according to a third embodiment in which a distributor having a large number of holes is arranged in a two-stage regenerator. FIG. 10 is a cross-sectional view of a distributor having a slit in the outer peripheral region and a plurality of holes in the central region arranged in a two-stage regenerator according to the fourth embodiment. FIG. 10 is a plan view of a distributor according to the fourth embodiment. FIG. 10 is a cross-sectional view according to the fifth embodiment, in which two distributors having a plurality of holes are combined in a two-stage shape regenerator so as to form a space. It is sectional drawing which provided the distributor comprised by the aggregate | assembly of many granular members concerning Example 6 in the two-stage regenerator. It is sectional drawing which provided the distributor comprised by the sintered member which concerns on Example 7 and which comprised many granular members in the two-stage shape regenerator. FIG. 10 is a circuit diagram according to Example 8 in which a two-stage regenerator is applied to a Stirling refrigerator. It is a circuit diagram which applied to the Stirling refrigerator the regenerator which makes | forms the cone shape which concerns on a prior art, and makes a flow-path cross-sectional area gradually increase as it goes to a high temperature side from a low temperature side. It is a block diagram of the regenerator which makes a right cylindrical shape in connection with a prior art.

Explanation of symbols

  In the figure, 4 is a regenerator, 4a and 4b are wire meshes, 40 is a case, 41 is a first cylinder, 41a is a first storage chamber, 42 is a second cylinder, 42a is a second storage chamber, 43 is a third cylinder, 43a is a 3rd storage chamber, 44 is a step part, 700 is a granular member, 701 is an aggregate | assembly, 750 shows a sintered member.

Claims (10)

A high-temperature side through which a high-temperature refrigerant gas passes, a low-temperature side through which a low-temperature refrigerant gas passes through, a case having a storage chamber that communicates with the high-temperature side and the low-temperature side and that stores a regenerator, and the storage chamber of the case In a regenerator used for a regenerative refrigerator, comprising a regenerative material housed therein,
The case is formed in a step-holding shape having at least one step portion between the high temperature side and the low temperature side, and the flow path cross-sectional area on the relatively low temperature side is relatively high in temperature. A regenerator for use in a regenerator type freezer characterized in that it is set smaller than the cross-sectional area of the flow path on the higher side.   The regenerator according to claim 1, wherein the regenerator material uses a wire mesh as a base material.   In Claim 1 or Claim 2, the number of meshes of the wire mesh disposed on the side having the larger flow path cross-sectional area in the housing chamber of the case is disposed on the side having the smaller flow path cross-sectional area in the housing chamber of the case. The regenerator is characterized by being set smaller than the number of meshes of the wire mesh.   The regenerator according to any one of claims 1 to 3, wherein a distributor is provided in a region facing the stepped portion in the case or in the vicinity of the region.   5. The regenerator according to claim 4, wherein the distributor has a plurality of holes for guiding the refrigerant gas.   6. The regenerator according to claim 4 or 5, wherein the distributor has a plurality of slits opened to the outer peripheral side so as to guide the refrigerant gas.   The distributor according to claim 4, comprising a first distributor part and a second distributor part arranged in parallel in a direction connecting the high temperature side and the low temperature side of the regenerator, A regenerator having a space through which refrigerant gas can flow is formed between the second distributor and the second distributor.   The regenerator according to any one of claims 4 to 7, wherein the distributor is configured by an aggregate of a plurality of granular members.   The regenerator according to any one of claims 1 to 8, wherein the distributor is formed of a porous member having a plurality of pores. In a regenerative refrigerator having a refrigeration system that generates a cryogenic temperature, the refrigeration system has a regenerator, and the regenerator passes a high temperature side through which a high-temperature refrigerant gas passes and a low-temperature refrigerant gas through. A case having a storage room for accommodating a cold storage material and communicating with the low temperature side and the high temperature side and the low temperature side; and a cold storage material accommodated in the accommodation chamber of the case,
The case is formed in a step-holding shape having at least one step portion between the high temperature side and the low temperature side, and the flow path cross-sectional area on the relatively low temperature side is relatively high in temperature. A regenerative refrigerator that is set smaller than the cross-sectional area of the flow path on the higher side.

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