JP6224676B2 - Parallel and distributed cooling system - Google Patents

Description

  The present invention relates to a parallel and distributed cooling system including a plurality of Stirling refrigerators and a plurality of thermosiphons in an ultra-low temperature large vertical freezer (ultra-low temperature tank).

  Conventionally, cooling systems using large compressors and CFC substitutes as refrigerants have been the mainstream for large freezers. However, ultra-low temperature tanks require high power and energy savings are desired. At the same time, special gases such as CFC-based gas and CFC substitutes are also required. Since the use of refrigerants is also restricted due to restrictions, making it difficult to use them, switching to a next-generation type cooling system using new refrigerants has been desired.

  Therefore, a Stirling refrigerator using helium gas as a refrigerant has been proposed as a next-generation energy-saving cooling device. As an example, an air cooling system has been proposed in which a Stirling refrigerator is disposed inside a freezer and a refrigerator is cooled using a thermosiphon condenser provided in the heat absorption part (see Patent Document 1).

  In addition, a drinking water cooling method has been proposed in which a thermosiphon has a plurality of paths, and the plurality of paths are arranged in a multiple spiral shape with respect to the outer periphery of the container (see Patent Document 2).

  Further, the thermosiphon has a plurality of paths, at least one path is disposed to descend along the half circumference of the container, and at least one other path descends along the other half circumference of the container. A cooling system is disclosed in which these paths are arranged so that the vicinity of the end part extending along the half circumference of the container is the lowest part (see Patent Document 3).

  However, none of the methods discloses an application example to an ultra-low temperature bath of −80 ° C. or lower. In particular, the air cooling system has a problem of freezing in the forced air circulation system (internal fan motor), which is difficult to realize in the ultra-low temperature field. In addition, it is suitable for refrigerators and refrigerators in multiple spiral and semi-circular loop piping routes applied to chillers and cold storage, etc., but it can be applied to vertical ultra-low temperature large vertical freezers with doors on the front side. It was difficult to achieve with a spiral or looped piping route. In addition, since the length of the piping path becomes long in a single-pipe loop shape or multiple spiral-shaped piping, there is a problem that it takes time for the refrigerant to circulate in the piping and cooling cannot be performed in a short time. .

Japanese Patent Laid-Open No. 2005-156011 JP 2005-308357 A JP 2007-93055 A

  The conventional techniques shown in the above-mentioned Patent Documents 1 to 3 are cooling systems that can be applied to household refrigerator-freezers, water coolers, small portable refrigerator-freezers, and the like, and can be adequately supported.

  However, in a vertical type ultra-low temperature large freezer of −80 ° C. or lower, the cooling wall is wide and long, so a large refrigerator is required. As this large refrigerator, a large special compressor type refrigerator or a large Stirling refrigerator having an output of about 500 W (watt) to 1 kW (kilowatt) is used, but the large special compressor type refrigerator has a large heat load. High power is required at startup. In addition, large Stirling refrigerators have a drawback that the cooling device is expensive and both have high running costs.

  In addition, if the thermosiphon is a single pipe or multiple pipes, if the pipe length becomes long, it takes time for the condensed and liquefied refrigerant to descend, and it takes time for the vaporized refrigerant to rise, so it is cooled to a predetermined temperature. In addition to extending the time required to perform the process, it is technically difficult to reach the ultra-low temperature range and to cool uniformly over the entire interior of the cabinet, and is not suitable for energy saving. Similarly, if the thermosyphon is tilted, the bend interval is widened, so that the temperature distribution on the cooling surface may be uneven, the internal temperature may not be uniform, and a temperature difference may occur. It was.

  For this reason, in order to achieve uniform temperature distribution and ultra-low temperature in a large-scale freezer, there is a limit to the cooling method using one large-scale refrigerator and the conventional piping path, improving the quality of ultra-low temperature refrigeration and improving the cooling efficiency. Improvement and energy saving were issues.

  The present invention has been made in view of such a situation, and a plurality of small or medium-sized Stirling refrigerators are dispersed in an ultra-low temperature large vertical freezer, and piping paths by a plurality of thermosiphons are simultaneously vertically divided. By arranging them in parallel, the cooling heat sources are distributed, the cooling piping paths are paralleled, the length per thermosiphon that is the piping path is shortened, the cooling speed is increased, and the piping path with a narrow pitch is made. It is an object of the present invention to provide a parallel distributed cooling system that is an energy-saving next-generation cooling method that makes it possible to equalize the temperature in the cabinet and improve cooling performance and cooling efficiency. Small or medium-sized Stirling refrigerators having an output of about 100 W to 200 W are widely spread in the market, and since the price is low, this system can be realized at low cost even when a plurality of units are used.

  In order to solve the above-described problems, a parallel and distributed cooling system including a plurality of Stirling refrigerators and a thermosiphon including a plurality of pipes according to the present invention employs the following means.

The parallel distributed cooling system of the present invention is a cooling system that directly cools the inside of an ultra low temperature large vertical freezer having a heat insulating layer made of a vacuum heat insulating material and a high density foam heat insulating material by a Stirling refrigerator and a thermosyphon. The ultra-low temperature large vertical freezer includes an inner shell formed in a hollow rectangular shape with an opening on the front side, the inner shell is disposed inside the heat insulating layer, and the Stirling refrigerator is disposed in the ultra-low temperature large vertical freezer. A plurality of units are arranged on the ceiling part of the mold freezer, a plurality of pipes are fixed to the heat absorption part of the Stirling refrigerator , the refrigerant is enclosed in the pipes, and the liquid that is liquefied with the refrigerant vaporized by heat exchange in the pipes refrigerant circulates mixed, left side, right side surface of the inner shell, the range is divided into a plurality rear of the transverse directions, front Sharing, ABS pipe continuously maintaining a predetermined tilt angle and spacing meander Do you Is disposed in contact with the inner shell to al descends, the plurality of the pipe which is disposed on the left side are arranged in parallel, a plurality of the pipe disposed on the right side is in parallel A plurality of the pipes arranged on the back surface are arranged in parallel, and when the Stirling refrigerator is driven, the inside of the ultra-low temperature large vertical freezer is cooled through the plurality of pipes. And

  Further, in the parallel distributed cooling system of the present invention, two or three of the Stirling refrigerators are arranged, and two or more pipes are fixed to a heat absorption part of one of the Stirling refrigerators, A fixing base for detachably attaching the pipe to the heat absorption part of the machine is provided.

In the parallel distributed cooling system of the present invention, the inner shell body has an inner shell wall formed of a composite material of two layers made of different materials, and the inner side of the inner shell wall has good rust prevention properties. A material is used, and a material having good thermal conductivity is used on the outside of the inner shell wall, and the piping is fixed in close contact with the outer surface of the inner shell wall.

  In the parallel distributed cooling system of the present invention, the upper ends or the lower ends of the plurality of pipes or both of them are connected, and a refrigerant inlet for injecting a refrigerant is provided at one place of the connected pipes. It is characterized by being covered with a heat insulating layer.

  According to the parallel distributed cooling system of the present invention, the inside of the ultra-low temperature large vertical freezer can be efficiently cooled, and the temperature distribution in the inside can be made uniform.

1 is a perspective view showing a first embodiment of a parallel distributed cooling system according to the present invention. It is sectional drawing which shows the principal part of the 1st Example of the parallel distributed cooling system which concerns on this invention. It is an expanded view which shows the inner shell of the 1st Example of the parallel distributed cooling system which concerns on this invention. It is an expanded view which shows the 2nd Example of the parallel distributed cooling system which concerns on this invention. It is a perspective view which shows the 3rd Example of the parallel distributed cooling system which concerns on this invention. It is a perspective view which shows the 4th Example of the parallel distributed cooling system which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention. In the present invention, the ultra-low temperature large vertical freezer is not limited to one in which the vertical length (height) of the freezer is longer than the horizontal length (horizontal width), and the ratio of the vertical and horizontal lengths is not limited. .

  Hereinafter, a first embodiment of a cooling system according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the ultra-low temperature large vertical freezer 1 according to this embodiment as viewed from the upper right on the back side. The ultra-low temperature large vertical freezer 1 includes an inner shell 2, an outer shell 3 that covers the upper side, lower side, left side, right side, and rear side of the inner shell 2, and a front door 4 that covers the front side of the inner shell 2. Two Stirling refrigerators 5A and 5B and a thermosiphon 6 are provided.

  The inner shell body 2 is formed in a hollow rectangular shape having an opening on the front side, and a storage portion 7 for storing an object to be cooled (not shown) is formed inside. The inner shell body 2 has a double wall structure in which an inner wall 11 and an outer wall 12 as inner shell walls are laminated. The inner wall 11 is made of stainless steel and has excellent rust prevention, and the outer wall 12 is made of copper and is thermally conductive. Are better. Thus, by using a double wall structure with two kinds of materials, both mechanical strength and excellent thermal conductivity can be provided. In this embodiment, the outer wall 12 completely covers the outer surface of the inner wall 11, but the outer wall 12 is disposed outside the inner wall 11 in order to efficiently cool the inside of the storage portion 7, and has an area of a certain degree or more. The inner wall 11 may not be completely covered.

  The outer shell 3 is formed in a hollow shape with an electrogalvanized steel sheet. The inner shell 2 is disposed inside the outer shell 3, and a gap between the inner shell 2 and the outer shell 3 is filled with a vacuum heat insulating material 28 described later. The outer surface of the outer shell 3 is baked with acrylic resin.

  The front door 4 is a hinged door that can be opened and closed forward. The front door 4 is formed by applying an acrylic resin baking coating on the surface of an electrogalvanized steel plate, like the outer shell 3.

  Two Stirling refrigerators 5 </ b> A and 5 </ b> B are installed symmetrically on the ceiling 13, which is the upper surface of the outer shell 3, located at the upper part of the ultra-low temperature large vertical freezer 1. The Stirling refrigerators 5A and 5B are so-called FPSC (free piston Stirling cooler). The Stirling refrigerators 5 </ b> A and 5 </ b> B are driven by electrical energy supplied from the electrical unit 8 using the electrical unit 8 similarly disposed on the ceiling 13 of the outer shell 3 as a drive source.

  As shown in FIG. 2, each of the Stirling refrigerators 5A and 5B is formed with an endothermic portion 14 whose temperature is reduced to about −90 ° C. to −120 ° C., and the endothermic portion 14 is an ultra-low temperature large vertical freezer 1. It protrudes in the back direction. A pipe fixing base 18 constituting a cooling part 15 of the thermosiphon 6 described later is attached to the heat absorbing part 14.

  The thermosiphon 6 includes two cooling units 15 and six pipes 16A to 16F. The cooling unit 15 includes a plate-shaped pipe fixing base 18 attached in contact with the front end surface 17 of the heat absorption part 14 of the Stirling refrigerators 5A and 5B, and a plate-shaped pipe that sandwiches the pipes 16A to 16F together with the pipe fixing base 18. The fixing plate 19 includes a plurality of fixing screws 20 that fix the pipe fixing base 18 and the pipe fixing plate 19.

  Three concave grooves (not shown) having a semicircular cross section extending in the vertical direction are formed on the surface of the pipe fixing base 18 that contacts the pipe fixing plate 19. On the other hand, three similar concave grooves (not shown) are formed on the surface of the pipe fixing plate 19 that contacts the pipe fixing base 18. Therefore, when the pipe fixing base 18 and the pipe fixing plate 19 are brought into contact with each other, three through holes (not shown) are formed by the concave grooves of the two, and the pipes 16A to 16F are inserted into the through holes one by one to be sandwiched. Is done.

  The pipe fixing base 18 and the pipe fixing plate 19 are made of copper, which is a metal having high thermal conductivity, and the surface thereof is plated with nickel. Therefore, the pipe fixing base 18 and the pipe fixing plate 19 can be efficiently cooled by the heat absorption part 14. The pipes 16A to 16C are fixed in contact with the pipe fixing base 18 and the pipe fixing plate 19 attached to the heat absorbing part 14 of the Stirling refrigerator 5A, and the pipes 16D to 16F are connected to the heat absorbing part 14 of the Stirling refrigerator 5B. The pipe fixing base 18 and the pipe fixing plate 19 to be attached are fixed in contact with each other.

  The pipes 16 </ b> A to 16 </ b> F are vertically extended and are sandwiched between a pipe fixing base 18 and a pipe fixing plate 19, and fixing screws 20 are inserted into screw holes (not shown) formed in the pipe fixing base 18 and the pipe fixing plate 19. It is fixed to the cooling unit 15 by screwing. Therefore, the Stirling refrigerators 5A and 5B can be attached and detached from the pipes 16A to 16F by attaching and detaching the fixing screw 20.

  In conventional large compressors, piping is directly connected, so if the refrigerator breaks down, repairs using welders and vacuum equipment are difficult, making it difficult to respond on-site and difficult to recover in a short time. On the other hand, although the Stirling refrigerators 5A and 5B of the present embodiment have high reliability, if there is a failure due to long-term use or the like, the pipes 16A to 16F and the Stirling refrigerators 5A and 5B are used. Is removable and separable, so that the failed Stirling refrigerator 5A, 5B itself can be replaced. Moreover, by using a plurality of Stirling refrigerators 5A and 5B as in this embodiment, the other Stirling refrigerators 5A and 5B continue to be cooled until the failed Stirling refrigerators 5A and 5B are replaced. Therefore, it is possible to avoid an abrupt increase in temperature and prevent the frozen sample or the frozen material stored in the storage unit 7 from being damaged by the increase in temperature. Therefore, not only the ease of assembly but also the redundancy and maintainability are improved.

  The pipes 16A to 16F are annealed copper pipes that are formed into thin tubes, have excellent pressure resistance, heat transfer, gas leakage resistance, and corrosion resistance, and can be easily bent. Can do. In addition, the pipes 16 </ b> A to 16 </ b> F are efficiently cooled by the heat absorbing unit 14 by being brought into contact with the pipe fixing base 18 and the pipe fixing plate 19. Hereinafter, a portion of the pipes 16 </ b> A to 16 </ b> F that is in contact with the pipe fixing base 18 and the pipe fixing plate 19 is referred to as a cooled portion 21.

  As shown in FIG. 2, portions of the heat absorbing unit 14, the cooling unit 15, and the pipes 16 </ b> A to 16 </ b> F that protrude from the outer shell 3 are disposed in rectangular cases 22 </ b> A and 22 </ b> B. In the cases 22A and 22B, a foam heat insulating material 23 such as high-density foam urethane is accommodated so as to cover a portion protruding from the outer shell 3 in the heat absorbing portion 14, the cooling portion 15, and the pipes 16A to 16F. The temperature rise of the heat absorption part 14, the cooling part 15, and piping 16A-16F by the heat outside the shell 3 is suppressed. Therefore, a heat insulating layer 29A is formed by the foam heat insulating material 23 in the cases 22A and 22B.

  The cases 22A and 22B can be divided into front and rear (front and rear of the ultra-low temperature large vertical freezer 1) at a substantially middle portion in the front and rear direction, and the foam heat insulating material 23 can also be divided into front and rear together with the cases 22A and 22B. The front side and the rear side of the cases 22A and 22B are fixed in contact with each other with screws or the like (not shown). When the rear sides of the cases 22A and 22B are removed, the pipe fixing plate 19 and the fixing screw 20 are exposed, and the fixing screw 20 can be attached and detached. Therefore, assembly work and replacement work of the Stirling refrigerators 5A and 5B can be easily performed.

  The pipes 16A to 16F fixed to the cooling unit 15 include a case hole 24 that is a through hole formed in the bottom surface of the cases 22A and 22B and an outer shell body that is a through hole formed in the ceiling portion 13 of the outer shell 3. The hole 25 is inserted into contact with the inner shell body 2. The case hole 24 and the outer shell hole 25 have such a size that the three pipes 16A to 16C and 16D to 16F can be inserted, and the case hole 24 and the outer shell body hole 25 are inserted in the state where the pipes 16A to 16C and 16D to 16F are inserted. The outer shell hole 25 is closed by a spacer 26 formed of a foam heat insulating material or a synthetic resin.

  As shown in FIG. 2, a heat insulating layer 29B in which a vacuum heat insulating material 28 is embedded in a high density foam heat insulating material 27 such as high density foamed urethane is formed in the gap between the inner shell 2 and the outer shell 3. By this heat insulation layer 29B, the temperature rise of the accommodating part 7 and piping 16A-16F is suppressed by the heat from the outside of the ultra-low temperature large vertical freezer 1. The vacuum heat insulating material 28 is disposed on the outer shell 3 side in the heat insulating layer 29B. However, since the vacuum heat insulating material 28 is embedded in the high density foam heat insulating material 27, the outer shell 3 and the vacuum heat insulating material 28 are disposed. A high-density foam heat insulating material 27 is disposed between them.

  Of the outer surface of the inner shell 2, pipes 6 </ b> A to 6 </ b> F are disposed in contact with the left side surface 31, the right side surface 32, and the back surface 33. The pipes 6 </ b> A to 6 </ b> F are fixed to the left side surface 31, the right side surface 32, and the back surface 33 with a heat conductive tape 34 such as copper or aluminum. Since the heat conductive tape 34 is affixed so that the part which contact | abuts the inner shell 2 among piping 6A-6F may be covered completely, the inner shell 2 can be cooled also with the heat conductive tape 34. It can be done.

  A refrigerant inlet 37 for injecting a cryogenic refrigerant gas selected from ethylene, ethane, propane, or the like, which is a natural refrigerant, is formed at the upper end 35A of the pipe 16A located above the portion to be cooled 21. This refrigerant is selected according to the cooling temperature of the ultra-low temperature large vertical freezer 1 and is sealed at a predetermined pressure, for example, a pressure of 1 MPa to 5 MPa. The refrigerant inlet 37 is sealed by a sealing member (not shown) after injecting the refrigerant.

  Hereinafter, the arrangement of the pipes 16A to 16F will be described with reference to FIGS. FIG. 3 is a development view of the inner shell 2 of the present embodiment, and shows only the pipes 16 </ b> A to 16 </ b> F and the cooling unit 15.

  The pipe 16A extends vertically downward from the cooling unit 15 disposed in the case 22A, and has a predetermined slope toward the left side 31 along the back surface 33 of the inner shell 2 and is downward. Is curved at the left connecting portion 38, which is a connecting portion between the left side surface 31 and the back surface 33, and extends downward along the left side surface 31 toward the front door 4 with a predetermined inclination. Yes. Then, it is bent and folded on the front door 4 side, is formed in a sinusoidal shape, and extends downward. In the present embodiment, the folded portion 39 that is bent and folded is formed at six locations on the front door 4 side and five locations on the rear surface 33 side, and more are formed on the front door 4 side. This is because when the front door 4 is opened, the front door 4 side of the storage unit 7 is most affected by the external temperature and the temperature is likely to rise, so that the cooling power on the front door 4 side is increased. .

  The pipe 16B is vertically extended downward from the cooling unit 15 disposed in the case 22A, and has a predetermined inclination toward the left side 31 along the back surface 33 of the inner shell 2 and downward. And is curved at the left connection portion 38, and extends downward along the left side surface 31 toward the pipe 16 </ b> A with a predetermined inclination. And it is formed in the shape of a sine curve substantially parallel to 16 A of piping, and is extended toward the downward direction.

  The lower end 40A of the pipe 16A and the lower end 40B of the pipe 16B are connected by a thin tubular lower connecting pipe 41 extending in the horizontal direction.

  The pipe 16C extends vertically downward from the cooling unit 15 disposed in the case 22A, is formed in a sinusoidal shape along the back surface 31 of the inner shell 2, and extends downward. ing.

  The pipe 16D extends vertically downward from the cooling unit 15 disposed in the case 22B, is formed in a sinusoidal shape along the back surface 31 of the inner shell 2, and extends downward. ing.

  The lower end 40C of the pipe 16C and the lower end 40D of the pipe 16D are connected by a thin tubular lower connecting pipe 42 extending in the horizontal direction. As shown in FIG. 3, the piping 16 </ b> C and the piping 16 </ b> D are arranged symmetrically with respect to the center line C in the left-right direction of the back surface 31 of the inner shell body 2.

  The pipe 16E extends vertically downward from the cooling unit 15 disposed in the case 22B, and has a predetermined inclination toward the right side 32 along the back surface 31 of the inner shell body 2 and below. Is curved at the left connecting portion 43, which is a connecting portion between the right side surface 32 and the back surface 31, and extends downward along the right side surface 32 toward the front door 4 with a predetermined inclination. Yes. Then, it is bent and folded on the front door 4 side, is formed in a sinusoidal shape, and extends downward.

  The pipe 16F extends vertically downward from the cooling unit 15 disposed in the case 22B, and has a predetermined inclination toward the right side surface 32 along the back surface 31 of the inner shell body 2 and below. And is curved at the left connection portion 43 and extends downward along the right side surface 32 toward the front door 4 with a predetermined inclination. And it forms in the shape of a sine curve substantially parallel to piping 16D, and is extended toward the downward direction. For the inclination of the pipes 16A to 16F, an angle at which the liquefied refrigerant smoothly flows downward, such as 45 ° or 60 °, is selected.

  The lower end 40E of the pipe 16E and the lower end 40F of the pipe 16F are connected by a thin tubular lower connecting pipe 44 extending in the horizontal direction. The material, inner diameter, and outer diameter of the lower connecting pipes 41, 42, 44 are the same as the material, inner diameter, and outer diameter of the pipes 16A to 16F. In the present embodiment, the pipes 16A to 16F have an outer diameter of 12 mm and a wall thickness of 1.5 mm, but the outer diameter and wall thickness can be changed as appropriate. About thickness, it can select according to the pressure in piping 16A-16F after enclosing a refrigerant | coolant.

  Since the lower connecting pipes 41, 42, 44 are all extended in the horizontal direction, when the liquefied refrigerant is stored in the lower ends 40A-40F of the pipes 16A-16F and the lower connecting pipes 41, 42, 44, all Since the water levels of the refrigerant in the pipes 16A to 16F are equal, the temperature of the stored refrigerant is uniform, the refrigerant circulation is not biased, and the cooling effect by the pipes 16A to 16F can be kept uniform.

  The upper end 35B of the pipe 16B and the upper end 35C of the pipe 16C are connected by a thin tubular upper connecting pipe 45, and the upper end 35D of the pipe 16D and the upper end 35E of the pipe 16E are connected by a thin tubular upper connecting pipe 46. Yes. Further, the upper end 35F of the pipe 16F is closed. Accordingly, the pipes 16A to 16F form a single pipe 16 that is all connected. As described above, the pipes 16A to 16F are all connected, and the refrigerant injection port 37 is provided only at one place, so that the refrigerant can be injected into the pipe 16 only once, and the pressures in the pipes 16A to 16F are made uniform. be able to. The material, inner diameter and outer diameter of the upper connecting pipes 45 and 46 are the same as the material, inner diameter and outer diameter of the pipes 16A to 16F.

  The pipe 16A is disposed on the front side surface 31A, which is the front side surface of the dividing line L obtained by dividing the left side surface 31 of the inner shell body 2 into the front and rear, and the pipe 16B is disposed on the left side surface 31 of the inner shell body 2 in the front and rear direction. It is disposed on the rear side surface 31B, which is the rear side surface of the dividing line L divided into two. The pipe 16C is disposed on the left side 33A, which is the left side of the center line C obtained by dividing the back 33 of the inner shell 2 into left and right, and the pipe 16D has the back 33 of the inner shell 2 left and right. It is arranged on the right side surface 33B which is the right side surface of the center line C divided into two. The pipe 16E is disposed on the rear side surface 32B, which is the rear side surface of the dividing line R obtained by dividing the right side surface 32 of the inner shell body 2 into the front and rear, and the pipe 16B is connected to the right side surface 32 of the inner shell body 2. Is arranged on the front side surface 32A, which is the front surface of the dividing line R divided into two in the front-rear direction. As described above, the inner shell body is formed by dispersing the six pipes 16 </ b> A to 16 </ b> F on the left side surface 31, the right side surface 32, and the back surface 33, which are the respective surfaces of the inner shell body 2, and extending in the vertical direction. The left and right side surfaces 31 and 32 and the back surface 33 of the two are substantially equally divided into six and cooled. In order to cool the left side surface 31, the right side surface 32, and the rear surface 33 of the inner shell 2 by arranging two pipes 16A and 16B, pipes 16C and 16D, and pipes 16E and 16F in parallel, the pipes Since the distance from the cooled portion 21 of 16A to 16F to the lower end 40A to 40F is shortened and the pipe pitch 47, which is the interval between adjacent portions of the folded pipes 16A to 16F, is narrowed, the temperature in the storage section 7 Can be rapidly cooled, and the inside of the storage unit 7 is uniformly cooled, so that temperature unevenness in the storage unit 7 can be suppressed.

  In this embodiment, the cooled parts 21 of the pipes 16A to 16F are vertically held between the pipe fixing base 18 and the pipe fixing plate 19, but the cooled parts 21 may be held at a predetermined inclination angle. The inclination of the cooled portion 21 can be selected in consideration of the fluidity of the refrigerant.

  Here, the cooling method of the inner shell 2 by the thermosiphon 6 will be described. When the electric energy is supplied from the electrical unit 8 and the Stirling refrigerators 5A and 5B start to drive, the temperature of the heat absorption unit 14 decreases, and the cooling unit 15 attached to the heat absorption unit 14 is cooled. And the to-be-cooled part 21 of piping 16A-16F which contact | abutted to the piping fixing stand 18 and the piping fixing plate 19 is cooled. When the cooled part 21 is cooled, the temperature of the refrigerant sealed in the pipes 16A to 16F decreases. The refrigerant cooled to the condensation temperature is liquefied and descends inside the pipes 16A to 16F due to gravity. Since the pipes 16A to 16F are in contact with the inner shell body 2, the refrigerant in the pipes 16A to 16F absorbs heat from the inner shell body 2, the temperature rises, and when the evaporation temperature is reached, the vaporized refrigerant is The pipes 16A to 16F are raised. The raised refrigerant reaches the cooled part 21 and is cooled again, and is condensed and liquefied to descend again in the pipes 16A to 16F. As described above, the refrigerant is formed inside the inner shell body 2 by repeating heat exchange and circulating inside the pipes 16 </ b> A to 16 </ b> F to absorb the heat of the inner shell body 2 to cool the inner shell body 2. The storage unit 7 can be cooled to the target temperature.

As described above, in this embodiment, the storage portion 7 as the inside of the ultra-low temperature large vertical freezer 1 having the heat insulating layer 29B made of the vacuum heat insulating material 28 and the high density foam heat insulating material 27 is used as the Stirling refrigerator 5A, 5B and the thermostat. A cooling system that directly cools by a siphon 6, wherein a plurality of Stirling refrigerators 5A, 5B are arranged on the ceiling of the ultra-low temperature large vertical freezer 1, and a plurality of pipes 16A- 16F is fixed, and the plurality of pipes 16A to 16F meander continuously with a predetermined inclination angle and interval, and the inner wall 11 as the inner shell wall and the rear wall 33 of the outer wall 12 and the left and right side surfaces 31, 32 descends in parallel along the Stirling refrigerator 5A, 5B are storage portion 7 is cooled via a plurality of pipes 16A~16F is driven cryogenic large vertical freezers 1 Thus, the pipes 16A to 16F are formed in an S shape with a length that is approximately half the width of each of the left side surface 31, the right side surface 32, and the rear surface 33 so that the predetermined inclination angle and interval are maintained from the lower end 40A to 40F. It becomes a continuous arrangement meandering and bent, the distance to the lower ends 40A to 40F is shortened, and the piping pitch 47 can be narrowed. That is, since the range in which one of the pipes 16A to 16F is cooled is narrow, the temperature difference in the temperature distribution of the inner shell 2 is reduced, and the inside of the storage unit 7 can be cooled in a short time.

  Further, in this embodiment, two Stirling refrigerators 5A and 5B are arranged, and two or more pipes 16A to 16C and 16D to 16F are fixed to the heat absorption part 14 of one Stirling refrigerator 5A and 5B. The pipes 16A to 16F are arranged in parallel by providing the pipe fixing base 18, the pipe fixing plate 19, and the fixing screw 20 as fixing parts for detachably attaching the pipes 16A to 16F to the heat absorbing part 14 of the Stirling refrigerators 5A and 5B. Moreover, since it is configured in a distributed manner, energy saving operation with high cooling efficiency is possible even with a large ultra-low temperature vertical freezer.

  Further, in this embodiment, the inner wall 11 and the outer wall 12 as the inner shell wall of the ultra-low temperature large vertical freezer 1 are formed of a two-layer composite material made of different materials, and the inside of the inner wall 11 and the outer wall 12 is rustproof. A good material is used, and the outside of the inner wall 11 and the outer wall 12 is made of a material having good thermal conductivity, and the pipes 16A to 16F are in close contact with the left side surface 31, the right side surface 32, and the rear surface 33 as the outer surfaces of the inner wall 11 and the outer wall 12. Thus, the inner surface of the inner shell 2 is enhanced in rust prevention, and the outer surface can be improved in thermal conductivity. Further, since the pipes 16A to 16F are in close contact with the left side surface 31, the right side surface 32, and the back surface 33, the inner shell body 2 can be efficiently cooled.

  In the present embodiment, the upper ends 35A to 35F and / or the lower ends 40A to 40F of the plurality of pipes 16A to 16F are connected to each other, and the refrigerant inlet 37 for injecting the refrigerant into one place of the connected pipes 16A to 16F is provided. The pipes 16A to 16F are covered with the heat insulating layers 29A and 29B, so that the pipes 16A to 16F become one pipe 16 and the refrigerant can be injected all at once, and the pressure inside the pipe 16 is increased. Can be made uniform, and the temperatures of the pipes 16A to 16F can be made uniform. Moreover, it can suppress that the temperature of piping 16A-16F rises with external heat by covering piping 16A-16F with the heat insulation layers 29A and 29B.

  In this embodiment, three pipes 16A to 16C and 16D to 16F are provided for the Stirling refrigerators 5A and 5B, respectively. However, the number of pipes provided for the Stirling refrigerators 5A and 5B is one, two. There may be four, five or more, and the Stirling refrigerator 5A and the Stirling refrigerator 5B may have different numbers of pipes.

  FIG. 4 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the lower connecting portions 41, 42, 44 and the upper connecting portions 45, 46 are not provided, and the pipes 16A to 16F are provided independently. Refrigerant injection ports 51A to 51F are respectively formed at the upper ends 35A to 35F of the pipes 16A to 16F, and the pipes 16A to 16F can individually inject the refrigerant. Further, the lower ends 40A to 40F of the pipes 16A to 16F are closed.

  Since the pipes 16A to 16F of the present embodiment are independent of each other, when repairing or replacing a part of the pipes 16A to 16F, only the pipes 16A to 16F to be repaired or replaced are removed. Often, repair and replacement work is simplified. Moreover, the kind and pressure of a refrigerant | coolant can be arbitrarily selected for every piping 16A-16F.

  In this embodiment, three pipes 16A to 16C and 16D to 16F are provided for the Stirling refrigerators 5A and 5B, respectively. However, the number of pipes provided for the Stirling refrigerators 5A and 5B is one, two. There may be four, five or more, and the Stirling refrigerator 5A and the Stirling refrigerator 5B may have different numbers of pipes.

  FIG. 5 shows a third embodiment of the present invention, in which the same parts as those in the first and second embodiments are denoted by the same reference numerals and detailed description thereof is omitted.

  The present embodiment is an ultra-low temperature large vertical freezer 1A that is larger than the first and second embodiments, and includes three Stirling refrigerators 61A to 61C and nine pipes 62A to 62I. That is, three pipes 62A to 62C, 62D to 62F, and 62G to 62I are fixed to the Stirling refrigerators 61A to 61C, and three pipes are provided on the left side surface 31, the right side surface 32, and the back surface 33 of the inner shell body 2, respectively. Piping 62A to 62C, 62D to 62F, and 62G to 62I.

  Upper ends 64A to 64C of the pipes 62A to 62C fixed to the Stirling refrigerator 61A are connected by an upper connecting pipe 65A. Further, upper ends 64D to 64F of the pipes 62D to 62F fixed to the Stirling refrigerator 61B are connected by an upper connecting pipe 65B. Further, upper ends 64G to 64I of the pipes 62G to 62I fixed to the Stirling refrigerator 61C are connected by an upper connecting pipe 65C. The material, inner diameter and outer diameter of the upper connecting pipes 65A to 65C are the same as those of the pipes 62A to 62I.

  Lower ends 67A to 67I (the lower ends 67G to 67I are not shown) of the pipes 62A to 62I are connected to a lower connecting pipe 68 that extends in the horizontal direction. The lower connecting pipe 68 extends from the vicinity of the front door 4 on the left side surface 31 to the vicinity of the front door 4 on the right side surface 32 along the left side surface 31, the back surface 33, and the right side surface 32. Curved and bent. The material, inner diameter and outer diameter of the lower connecting pipe 68 are the same as those of the pipes 62A to 62I.

  As described above, the pipes 62A to 62I are connected by the upper connecting pipes 65A to 65C and the lower connecting pipe 68, and the pipes 62A to 62I, the upper connecting pipes 65A to 65C, and the lower connecting pipe 68 are all connected. 62 is formed. In addition, since the refrigerant inlet 66 for injecting the refrigerant into the pipe 62 is formed in the upper connecting pipe 65B, the refrigerant can be injected into the pipe 62 at one time, and the pressure in the pipe 62 is reduced. It can be made uniform.

  Next, the arrangement of the pipes 62A to 62I will be described. The pipes 62 </ b> A to 62 </ b> C are vertically extended downward from the cooling unit 15 (not shown in FIG. 5), are curved at a position reaching the upper surface 69 of the inner shell 2, and are upper surfaces 69 toward the left side surface 31. And is curved at the connecting portion 70 between the upper surface 69 and the left side surface 31, and extends downward along the left side surface 31 with a predetermined inclination toward the front door 4. Then, it is bent and folded on the front door 4 side, is formed in a sinusoidal shape, and extends downward. Therefore, the pipes 62 </ b> A to 62 </ b> C are formed in substantially the same shape on the left side surface 31 substantially in parallel.

  The pipes 62D to 62F extend vertically downward from the cooling unit 15 (not shown in FIG. 5), abut against the back surface 33 of the inner shell 2, and the pipe 62D has a predetermined direction toward the left side surface 31. The pipe 62 </ b> E extends vertically downward, and the pipe 62 </ b> E extends downward with a predetermined slope toward the right side surface 32. And piping 62D-62F is formed in the shape of a sine curve, and is extended toward the downward direction. Accordingly, the pipes 62 </ b> D to 62 </ b> F are formed in substantially the same shape on the back surface 33 in substantially parallel.

  The pipes 62 </ b> G to 62 </ b> I extend vertically downward from the cooling unit 15 (not shown in FIG. 5), bend at a position reaching the upper surface 69 of the inner shell 2, and move toward the right side surface 32. And is curved at the connecting portion 71 between the upper surface 69 and the right side surface 32, and extends downward along the right side surface 32 toward the front door 4 with a predetermined inclination. Then, it is bent and folded on the front door 4 side, is formed in a sinusoidal shape, and extends downward. Accordingly, the pipes 62G to 62I are formed in substantially the same shape on the right side surface 32 substantially in parallel.

  As described above, in this embodiment, three Stirling refrigerators 61A to 61C are arranged, and three pipes 62A to 62C, 62D to 62F, and 62G to 62I are provided in the heat absorption part 14 of one Stirling refrigerator 61A to 61C. Are fixed, and the pipe fixing base 18, the pipe fixing plate 19, and the fixing screw 20 are provided as fixing parts for detachably attaching the pipes 62A to 62I to the heat absorbing parts 14 of the Stirling refrigerators 61A to 61C. Since 62I is configured in parallel and in a distributed manner, an energy saving operation with high cooling efficiency is possible even with a further ultra-low temperature vertical freezer.

  In this embodiment, three pipes 61A to 61C, 61D to 61F, and 61G to 61I are provided in the Stirling refrigerators 61A to 61C, respectively, but the number of pipes provided in the Stirling refrigerators 61A to 61C is one. The number may be two, four, five, or more, and each Stirling refrigerator 61A to 61C may include a different number of pipes.

  FIG. 6 shows a fourth embodiment of the present invention, in which the same parts as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, two pipes 62A and 62C, pipes 62D and 62F, and pipes 62G and 62I are provided in each of the Stirling refrigerators 61A to 61C of the ultra-low temperature large vertical freezer 1A of the third embodiment. That is, the pipes 62B, 62E, and 62H are not provided. Further, the Stirling refrigerator 61A is arranged so that the cooling unit 15 faces the left side surface 31, and the Stirling refrigerator 61C is arranged so that the cooling unit 15 faces the right side 32.

  In the present embodiment, the pipes 62A, 62C, 62G, and 62I do not need to be brought into contact with the upper surface 69, but may be extended vertically downward and brought into contact with the left side surface 31 and the right side surface 32. , 62C, 62G, and 62I are not required to bend for contacting the upper surface 69.

  The pipe 62A is arranged in a sinusoidal shape in the range of the front half of the left side surface 31, and the pipe 62C is arranged in a sinusoidal shape in the range of the rear half of the left side surface 31, both being substantially the same in parallel. It is formed into a shape.

  The pipe 62D is arranged in a sinusoidal shape in the range of the left half of the back surface 33, and the pipe 62F is arranged in a sinusoidal shape in the range of the right half of the back surface 33, and both are formed in substantially the same shape in parallel. Has been. The pipe 62D and the pipe 62F may be arranged so as to be bilaterally symmetric as in the pipes 16C and 16D of the first embodiment shown in FIGS. 1 and 3 and the second embodiment shown in FIG.

  The pipe 62G is disposed in a sinusoidal shape in the range of the rear half of the right side surface 32, and the pipe 62I is disposed in a sinusoidal shape in the range of the front half of the right side surface 32. It is formed into a shape.

  In the present embodiment, two pipes 62A and 62C, pipes 62D and 62F, and pipes 62G and 62I are provided for the Stirling refrigerators 61A to 61C, respectively, but the number of pipes provided for the Stirling refrigerators 61A to 61C. May be one, three, four, five or more, and each Stirling refrigerator 61A-61C may be provided with a different number of pipes.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, the pipe is not limited to a single pipe, and a wick may be formed inside to promote circulation of the refrigerant in the pipe. The pipe may be formed of stainless steel. The number of Stirling refrigerators may be four, five, or more depending on the size of the ultra-low temperature vertical freezer.

1,1A cryogenic large vertical location freezers 5A, 5B Stirling refrigerator 6 Thermo siphon down
7 storage (inside)
8 electrical units
11 inner wall (inner shell wall)
12 Outer wall (inner shell wall)
16A-F Piping 18 Piping fixing base (fixing part)
19 Piping fixing plate (fixing part)
20 Fixing screw (fixing part)
27 High-density foam heat insulating material 28 Vacuum heat insulating material 29A, 29B Heat insulating layer 31 Left side surface (outer surface of inner shell wall)
32 Right side (outer surface of inner shell wall)
33 Back (outer surface of inner shell wall)
35A-35F Upper end 37 Refrigerant inlet 40A-40F Lower end 47 Piping pitch (interval)
61A to 61C Stirling refrigerator 62A to 62I Piping 64A to 64I Upper end 66 Refrigerant inlet 67A to 67I Lower end

Claims (4)

A cooling system that directly cools the inside of an ultra-low temperature large vertical freezer having a heat insulating layer made of a vacuum heat insulating material and a high-density foam heat insulating material by a Stirling refrigerator and a thermosyphon,
The ultra-low temperature large vertical freezer includes an inner shell formed in a hollow rectangular shape with an open front, and the inner shell is disposed inside the heat insulating layer,
A plurality of the Stirling refrigerators are arranged on the ceiling of the ultra-low temperature large vertical freezer,
A plurality of pipes are fixed to the heat absorption part of the Stirling refrigerator,
The pipe is filled with a refrigerant, and the refrigerant vaporized by heat exchange in the pipe and the liquefied refrigerant are mixed and circulated.
Left side of the inner shell, a right side, the range is divided into a plurality rear of the transverse directions, front Sharing, ABS pipe said to descend while meandering continuously maintaining a predetermined tilt angle and spacing Arranged in contact with the shell ,
A plurality of the pipes arranged on the left side surface are arranged in parallel,
A plurality of the pipes arranged on the right side surface are arranged in parallel,
A plurality of the pipes arranged on the back surface are arranged in parallel,
When the Stirling refrigerator is driven, the inside of the ultra-low temperature large vertical freezer is cooled via the plurality of pipes. Two or three Stirling refrigerators are arranged,
Two or more pipes are fixed to the heat absorption part of one Stirling refrigerator,
The parallel distributed cooling system according to claim 1, further comprising a fixing unit that detachably attaches the pipe to the heat absorption unit of the Stirling refrigerator. The inner shell has an inner shell wall formed of a two-layer composite material made of different materials,
The inside of the inner shell wall uses a material with good rust prevention, the outside of the inner shell wall uses a material with good thermal conductivity,
The parallel distributed cooling system according to claim 1 or 2, wherein the piping is fixed in close contact with an outer surface of the inner shell wall. The upper end or lower end of the plurality of pipes or both are connected,
Providing a refrigerant inlet for injecting the refrigerant into one of the connected pipes;
The parallel distributed cooling system according to claim 1, wherein the pipe is covered with the heat insulating layer.

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