KR20090008343A - Freezing device - Google Patents

Abstract

A freezing device where the temperature etc. in a storage room can be measured by using a measurement hole without affecting an installation environment. The freezing device (1) has a low temperature side refrigerant circuit (38) constructed from a compressor (20), an evaporation pipe (62), etc. and cools the storage room (4), formed in an heat insulation box body (2) by using the evaporation pipe (62), down to extreme cold temperature. A machine room (3) is provided beside the heat insulation box body (2) and has the compressor (20) etc. installed in it. The measurement hole (19) communicating with the inside of the storage room (4) is formed in the side wall on the machine room (3) side of the heat insulation box body (2).

Description

Refrigeration unit {FREEZING DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device having a refrigerant circuit composed of a compressor, an evaporator, and the like, wherein the storage compartment formed in the heat insulating housing is cooled by an evaporator at an extremely low temperature.

Conventionally, in the refrigerating apparatus which keeps a high temperature in a cryogenic body, the main body is comprised by the heat insulation housing comprised by filling a foam heat insulating material in the space comprised by combining an inner case and an outer case, and is stored in the storage compartment formed in the said heat insulation housing, for example, For example, a cryogenic space such as -80 ° C. or less is formed by a two-dimensional refrigeration apparatus (see Patent Document 1).

In general, a refrigerating device that maintains the inside of a storage compartment at an extremely low temperature such as −80 ° C. or less is constituted by an insulating housing having an opening on its upper surface and an insulating door that closes and closes the opening of the upper surface so as to be two-dimensional on the side of the insulating housing. The machine room which arranges the refrigeration system of a refrigeration system is formed. The heat insulating housing is filled with a considerably thick heat insulating material between the inner case and the outer case in consideration of the temperature difference in the outer case and the inner case in order to reduce the leakage amount of cold heat in the inner case.

On the other hand, the refrigerating device is used for preservation of living cells and the like in a chemistry laboratory and the like, and may sometimes accurately measure and record the temperature at which the sample housed in the storage chamber is actually stored. In such a case, it is necessary to install a temperature sensor for measuring the temperature in the actual storage chamber, rather than a temperature control temperature sensor installed in the refrigerating device, for example in a sample in the storage chamber, and a measurement hole for introducing the temperature sensor. Become.

10 shows a perspective view of a conventional refrigeration apparatus 100. The refrigeration apparatus 100 is constituted by a heat insulating housing 101 having an opening on an upper surface thereof, and forming a storage compartment therein, and a machine chamber 102 formed adjacent to the side of the heat insulating housing 101, and insulated. The top opening of the housing 101 is closedly openable by the heat insulation door 103. And the measurement hole 105 is formed in the side surface 101A located in the side opposite to the side in which the machine room 102 of this heat insulation housing 101 is formed.

The measurement hole 105 can insert a temperature sensor from the outside into the storage chamber, and the wiring drawn out from the temperature sensor is connected to the external recording apparatus main body via the measurement hole 105. This measuring hole 105 is closed by a stopper 106 made of a sponge-like deformable special material to form a gap with the wiring. In addition, in the state in which the temperature sensor is not provided, the measurement hole 105 is thermally closed by the said stopper 106. As shown in FIG.

Patent Document 1: Japanese Patent Application Laid-open No. 62-73046

Since the refrigeration unit is often installed along a wall or other device in a chemistry laboratory or the like, if a measurement hole is formed in the back of the reservoir, it becomes difficult to put in and out a recording temperature sensor, thereby forming a machine room of an insulated housing. It is often formed in the side which is located on the opposite side to become a side.

However, in such a structure, when the said refrigeration apparatus is installed, if the side surface of the heat insulation housing of the side in which the measurement hole is formed is not provided predetermined distance from the wall or other apparatus, such as a laboratory, the said measurement hole will be used. There was a problem that became difficult.

On the other hand, this refrigeration apparatus needs to use a heat insulating housing filled with a heat insulating material of a predetermined thickness in order to keep the inside of the storage chamber at a predetermined cryogenic temperature as described above. As a result, the overall size of the volume in the storage compartment is increased. In addition to this, in order to use the measuring hole, a refrigeration apparatus must be provided at a predetermined distance from a wall or other equipment such as a laboratory, and thus there is a problem that the area required for installation of the refrigeration apparatus is enlarged.

Accordingly, an object of the present invention is to provide a refrigerating device that enables measurement of a temperature and the like in a storage chamber using a measurement hole without affecting the installation environment.

The refrigerating device of the present invention includes a refrigerant circuit composed of a compressor, an evaporator, and the like, which is formed by cooling a storage compartment configured in an insulating housing by an evaporator at an extremely low temperature, and has a machine room configured on the side of the insulating housing and installed with a compressor. The measurement hole which communicates in a storage chamber is comprised in the side wall of the machine room side of a heat insulation housing, It is characterized by the above-mentioned.

In the refrigeration apparatus of Claim 2, in the said invention, the heat insulation housing is formed in the composite structure of a vacuum heat insulation panel and a foam heat insulating material, and arrange | positioned the vacuum heat insulation panel in the front and back walls of a heat insulation housing, and the side wall on the opposite side to a machine room. It is characterized by.

In the above-mentioned each invention, the refrigeration apparatus of Claim 3 provided the opening and closing panel which conceals a measuring hole in the machine room. It is characterized by the above-mentioned.

The refrigeration apparatus of Claim 4 was comprised in the said invention WHEREIN: The ceiling panel of a machine room was comprised so that opening and closing was possible, and the measurement hole was made operable in the state which opened the said ceiling panel.

According to the present invention, there is provided a refrigerant circuit comprising a compressor, an evaporator, and the like, wherein the storage compartment configured in an insulating housing is cooled by an evaporator at an extremely low temperature. And a measuring hole communicating with the storage chamber on the side wall of the machine room side of the heat insulating housing, thereby inserting the measuring device which is the above-mentioned temperature sensor for recording into the measuring hole from the machine room side, thereby easily installing the measuring device in the storage chamber. It becomes possible.

As a result, even when the refrigeration apparatus is installed adjacent to a wall or other equipment of the installation environment, there is no need for a space necessary for using the measurement holes. Therefore, the area required for installation of the refrigeration apparatus can be narrowed. It becomes possible to plan. It becomes suitable for the layout of a laboratory etc.

According to the invention of claim 2, in the invention, the heat insulating housing is formed of a composite structure of a vacuum heat insulating panel and a foamed heat insulating material, and the vacuum heat insulating panel is disposed in the front and rear walls of the heat insulating housing and in the side walls opposite to the machine room. Since it does not affect the position of the measurement hole formed in the heat insulation housing, it becomes possible to arrange | position a vacuum heat insulation panel in a heat insulation housing, and can reduce the leakage amount of the cooling heat in a storage chamber, and suppress waste of unnecessary cooling energy. It becomes possible.

In particular, by arranging the vacuum insulation panel in the front and rear walls of the insulation housing configured to face the outside and the side wall on the side opposite to the machine room, even when the inside of the storage compartment becomes an ultra low temperature such as -150 ° C or lower, the insulation is insulated. It is possible to improve the thermal insulation performance of the housing itself, and to reduce the size, and to increase the storage volume in the storage compartment even in the same external dimensions as in the prior art. Or even if it is the same storage volume as before, it becomes possible to reduce an external dimension, and also by this, it becomes possible to aim at the narrowing of the area required for installation of a refrigeration apparatus.

Moreover, according to invention of Claim 3, in each said invention, by providing the opening and closing panel which hides a measurement hole in a machine room, it can be set as the structure which does not expose a measurement hole to an external appearance, and aims at improvement of an external appearance. It becomes possible.

According to the invention of claim 4, in the above invention, the machine room ceiling panel is configured to be openable and closed, and the measurement hole can be operated with the ceiling panel open. Therefore, the workability can be improved. In addition, operation to other equipment in the machine room becomes easy, and maintenance work can be improved.

1 is a perspective view of a refrigeration apparatus to which the present invention is applied.

2 is a front view of the refrigeration apparatus of FIG.

3 is a plan view of the refrigeration apparatus of FIG.

4 is a side view of the storage chamber of the refrigerating device of FIG.

Fig. 5 is a perspective view of the refrigeration apparatus with the ceiling panel open.

6 is a refrigerant circuit diagram of the refrigeration apparatus of FIG.

7 is a perspective view of the thermal insulation structure.

8 is a perspective view of a state in which the heat insulating material of the heat insulating structure is removed.

9 is a rear perspective view of the refrigerating device showing a state in which a heat insulating structure is provided.

10 is a perspective view of a conventional refrigeration apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings. 1 is a perspective view of a refrigerating apparatus 1 to which the present invention is applied, FIG. 2 is a front view of the refrigerating apparatus 1, FIG. 3 is a plan view of the refrigerating apparatus 1, and FIG. 4 is a storage chamber 4 of the refrigerating apparatus 1. Fig. 5 shows a perspective view of the refrigerating device 1 in a state where the ceiling panel 5 is opened. The refrigerating device 1 of the present embodiment is suitable for cryogenic storage such as biological tissues or specimens for long-term low temperature storage, and is provided on the side of the heat insulating housing 2 open to the top and the heat insulating housing 2. The main body is comprised by the machine room 3 which locates and the compressor 10 etc. are installed in it.

This insulating housing 2 is connected between the outer case 6 made of steel plate which opened the upper surface, the inner case 7 made of metal, such as aluminum with good thermal conductivity, and the upper ends of these boxes 6 and 7. The breaker 8 made of synthetic resin, and the polyurethane resin insulating material 9 filled in the space surrounded by the outer case 6, the inner case 7 and the breaker 8 by the field foam method. The inner case 7 is configured as a storage compartment 4 having an open top surface.

In the present embodiment, the heat insulating housing 2 partitioning the inside of the storage compartment 4 and the outside air in order to set the temperature (hereinafter, referred to as a high internal temperature) in the target storage compartment 4 to be −150 ° C. or less, for example. Compared with the low temperature which sets the internal temperature of high temperature to near 0 degreeC, large heat insulation ability is needed. Therefore, in order to ensure the said heat insulation capability only by the heat insulating material 9 made of polyurethane resin as mentioned above, it must form very thick, and the problem that the storage amount in the storage chamber 4 cannot fully be secured by the limited main body dimension is made. There is.

Therefore, the heat insulation housing 2 in this embodiment has side walls 6C which are located on the opposite side to the side where the front wall 6A, the back wall 6B, and the machine room 3 of the outer case 6 are installed. After the glass insulation vacuum insulation panel 12 is arrange | positioned at each inner wall surface of a), and one end is temporarily fixed by double-sided adhesive tape, the heat insulating material 9 is foamed between these boxes 6 and 7 on-site. To charge.

This vacuum heat insulating panel 12 accommodates the glass wool which has heat insulation in the container comprised by the multilayer film which consists of aluminum, synthetic resin, etc. which do not have air permeability. Thereafter, the air in the container is discharged by a predetermined vacuum evacuation means, and the opening of the container is joined by thermal welding. Therefore, the vacuum insulation panel 12 can obtain the same heat insulation effect by making the thickness dimension of the heat insulating material 9 thinner than the conventional one by the said heat insulation performance.

On the other hand, the evaporator (evaporation pipe) 62 which comprises the refrigerant circuit of the cooling apparatus R mentioned later in detail is provided in the circumferential surface by the heat insulating material 9 side of the inner case 7 so that heat exchange is possible.

In addition, the upper surface of the breaker 8 of the heat insulation housing 2 comprised as mentioned above is shape | molded in step shape as shown in FIG. 2 or FIG. 4, and the heat insulation door ( 13) is rotatably installed by the pivot members 14 and 14 around one end, and in this embodiment, the rear end. In addition, the upper surface opening of the said storage chamber 4 is provided so that the inner cover 15 which consists of a heat insulating material can be opened and closed. Moreover, the lower part of the heat insulation door 13 is provided with the press part which protrudes below, and the press part of the heat insulation door 13 presses the inner cover 15, and thereby the upper surface of the storage chamber 4 by this. The opening is closed to be openable. In addition, the handle 16 is provided in the other end part of the heat insulation door 13, and in this embodiment, the front end part, and the heat insulation door 13 is opened and closed by operating the said handle 16. As shown in FIG.

On the other hand, in the side of the heat insulating housing 2, the machine room is formed by a side panel 3B constituting a side of the front panel 3A, a rear panel (not shown) and a side opposite to the side on which the heat insulating housing 2 is installed. (3) is installed. The machine room 3 in this embodiment is provided with partition plates 17 for dividing the interior up and down. The compressor 10, 20 etc. which comprise the cooling apparatus R are accommodated under the partition board 17, and the front panel 3A located under the said partition board 17 is provided. And 3 C of ventilation slits are formed in the side panel 3B.

Above the partition plate 17, it becomes the upper machine room 18 by which an upper surface is opened. In the upper surface opening of the upper machine room 18, the ceiling panel 5 is rotatably provided around one end, and in the present embodiment, the rear end part, whereby the inside of the upper machine room 18 is closed to be opened and closed. Moreover, the panel located and installed in the front surface of the upper machine room 18 is the operation panel 21 for operating the said refrigeration apparatus 1.

The measurement hole 19 is formed in the side surface of the heat insulating housing 2 side which comprises this upper machine room 18. As shown in FIG. This measuring hole 19 is an outer case 6, a heat insulating material 9, and an inner case 7 constituting the heat insulating housing 2 so as to communicate with a storage compartment 4 formed in the heat insulating housing 2 which is adjacently installed. It is formed through. The measurement hole 19 can insert a temperature sensor into the storage chamber 4 from the outside, and the wiring drawn out from the temperature sensor is connected to the external recording apparatus main body via the measurement hole 19. The measuring hole 19 is closed by a stopper 19A made of a special material that can be deformed in a sponge shape and has heat insulation. In addition, in the state in which the temperature sensor is not provided, the measurement hole 19 is adiabaticly closed by the said stopper 19A.

As a result, when using a device that measures, records, or the like in the storage compartment 4, the heat insulating housing located in the upper machine chamber 18 by opening the ceiling panel 5 provided in the machine chamber 3. Through the measuring hole 19 formed in the side surface of 2) side, it becomes possible to insert the said measuring instrument in the storage chamber 4. Therefore, the work which installs a measuring instrument in the storage chamber 4 cooled to predetermined | prescribed ultra low temperature becomes easy.

In particular, since the measurement hole 19 in this embodiment is formed in the side surface of the machine room 18 side of the heat insulation housing 2 unlike the measurement hole provided in the conventional refrigeration apparatus, the said refrigeration apparatus 1 Even if the sensor is installed adjacent to a wall or other equipment of an installation environment such as a laboratory, there is no need for a gap necessary for using the measuring hole 19 particularly. Thereby, it becomes possible to narrow the area required for installation of the refrigerating device 1, and it becomes suitable for layout of a laboratory etc.

Moreover, since the measurement hole 19 is formed in the wall surface of the heat insulation housing 2 of the side adjacent to the machine room 3, heat insulation comprised in the side surface other than adjacent to the machine room 3, ie, facing the outside, is comprised. On the front and rear walls and side surfaces of the housing 2, it becomes possible to arrange | position the vacuum heat insulation panel 12 as mentioned above without affecting the formation position of the measurement hole 19. FIG.

Moreover, the heat insulation structure in which the cascade heat exchanger 43, each intermediate heat exchanger 48, etc. were integrally formed with the heat insulating material in the wall surface of the heat insulation housing 2 in which the said measurement hole 19 is formed as mentioned later in detail. Since 70 is arrange | positioned, even if the vacuum heat insulation panel 12 is not provided, it becomes possible to heat-insulate the inside of the storage chamber 4 by the said heat insulation structure 70 effectively.

Thereby, the leakage amount of the cooling heat in the storage chamber 4 can be reduced, and it becomes possible to suppress waste of unnecessary cooling energy.

Therefore, even when the inside of the storage chamber 4 is made into the ultra low temperature like -150 degrees C or less like this embodiment, it becomes possible to improve the heat insulation performance of the heat insulation housing 2 itself, It is possible to reduce the size and to increase the storage volume in the storage chamber 4 even in the same external dimensions as in the prior art. Or even if it is the same storage volume as the conventional one, it becomes possible to reduce an external dimension, and also by this, it becomes possible to narrow the area for the installation of the refrigeration apparatus 1 required.

In addition, since the measurement hole 19 in this embodiment can be concealed by the ceiling panel 5 which can open and close the upper surface opening of the upper machine room 18, the measurement hole 19 is not exposed to the external appearance. It is possible to improve the appearance. In addition, by opening the ceiling panel 5, the operation to the measurement hole 19 can be easily performed, and workability can be improved. Moreover, by removing the partition plate 17, the operation by the apparatus which comprises the other cooling apparatus R provided below the partition plate 17 also becomes easy, and it becomes possible to improve maintenance work. The ceiling panel 5 can be used also as a working base by leaving the inside of the machine room 18 closed except for the operation to the measurement hole 19. It becomes suitable for the operation | work of taking-out of articles, such as a sample, in the storage chamber 4, etc.

In addition, in this embodiment, although the measurement hole 19 is concealed by the ceiling panel 5 which obstruct | occludes the upper surface opening of the upper machine room 18, it is not limited to this, It is not limited to the measurement hole 19 vicinity. It may be provided with a cover member or the like for concealing the measurement hole 19.

Next, the refrigerant circuit of the refrigerating device 1 of this embodiment will be described with reference to FIG. The refrigerant circuit of the refrigerating device 1 in this embodiment is a multi-stage multistage refrigerant circuit, each having a high temperature side refrigerant circuit 25 as an independent first refrigerant circuit and a low temperature side refrigerant circuit 38 as a second refrigerant circuit. Is composed of a two-way two-stage refrigerant circuit.

The compressor 10 constituting the high temperature side refrigerant circuit 25 is an electric compressor using one-phase or three-phase AC power, and the discharge-side piping 10D of the compressor 10 is connected to the auxiliary condenser 26. . This auxiliary condenser 26 is connected to the refrigerant pipe 27 (henceforth a frame pipe) arrange | positioned on this side of this opening edge in order to heat the storage edge of the storage chamber 4, and to prevent dew condensation. In addition, the frame pipe 27 is connected to the oil cooler 29 of the compressor 10 and then to the condenser 28. After the refrigerant pipe leaving the condenser 28 is connected to the oil cooler 30 of the compressor 20 constituting the low temperature side refrigerant circuit 38, the refrigerant pipe is connected to the condenser 31 to connect the condenser 31. The exit refrigerant pipe is connected to the evaporator 34 as the evaporator part constituting the evaporator in turn through the dryer 32 and the capillary tube 33 as the pressure reducing device. An accumulator 35 serving as a refrigerant liquid storage part is connected to the outlet refrigerant pipe of the evaporator 34, and the refrigerant pipe leaving the accumulator 35 is connected to a suction side pipe 10S of the compressor 10. In addition, the auxiliary condenser 26 and the condenser 28 and 31 in this embodiment are comprised as an integral condenser, and are cooled by the blower 36 for condenser.

The high temperature side refrigerant circuit 25 is filled with a refrigerant composed of R407D and n-pentane as an azeotropic refrigerant having a different boiling point. R407D is R32 (difluoromethane: CH ₂ F ₂ ), R125 (pentafluoroethane: CHF ₂ CF ₃ ), and R134a (1,1,1,2-tetrafluoroethane: CH ₂ FCF ₃ ) The composition is 15 weight% of R32, 15 weight% of R125, and 70 weight% of R134a. The boiling point of each refrigerant | coolant is -51.8 degreeC of R32, -48.57 degreeC of R125, and -26.16 degreeC of R134a. In addition, the boiling point of n-pentane is +36.1 degreeC.

The hot gaseous refrigerant discharged from the compressor 10 is the oil cooler of the compressor 20 of the auxiliary condenser 26, the frame pipe 27, the oil cooler 29, the condenser 28, and the low temperature side refrigerant circuit 38. 30, after condensation by the condenser 31 to liquefy the heat dissipation, the water contained in the dryer 32 is removed, depressurized by the capillary tube 33, continuously introduced into the evaporator 34, and the refrigerant R32, R125 and R134a evaporate, absorb the heat of vaporization from the surroundings, cool the evaporator 34, and return to the compressor 10 via the accumulator 35 as the refrigerant liquid storage unit.

At this time, the capacity of the compressor 10 is, for example, 1.5 HP, and the final attained temperature of the evaporator 34 during operation is -27 ° C to -35 ° C. Under such low temperatures, since n-pentane in the refrigerant has a boiling point of + 36.1 ° C., it does not evaporate in the evaporator 34 and remains in a liquid state, and thus contributes little to cooling, but the lubricant or the dryer 32 of the compressor 10 is not. And the function of reducing the temperature of the compressor 10 by returning the mixed water which has not been completely absorbed into the compressor 10 to the compressor 10 in a state dissolved therein and by evaporation of the liquid refrigerant in the compressor 10. Exert.

On the other hand, the low temperature side refrigerant circuit 38, the compressor 20 is an electric compressor using a single-phase or three-phase AC power source similar to the compressor 10, and the discharge side pipe 20D of the compressor 20 has a wire. The oil separator 40 is connected via a radiator 39 composed of a capacitor. The oil separator 40 is connected to an oil return pipe 41 returned to the compressor 20. The refrigerant pipe connected to the outlet side of the oil separator 40 is connected to the condensation pipe 42 as the high pressure side pipe inserted into the evaporator 34. This condensation pipe 42 constitutes the cascade heat exchanger 43 together with the evaporator 34.

The discharge pipe connected to the outlet side of the condensation pipe 42 is connected to the first gas-liquid separator 46 via the dryer 44. The gaseous phase refrigerant separated by the gas-liquid separator 46 passes through the first intermediate heat exchanger 48 through the gas-phase pipe 47 and flows into the second gas-liquid separator 49. The liquid refrigerant separated by the first gas-liquid separator 46 flows into the first intermediate heat exchanger 48 via the dryer 51 and the capillary tube 52 as a pressure reducing device through the liquid pipe 50 to obtain the gaseous refrigerant. Cooling by evaporation.

The liquid refrigerant separated by the second gas-liquid separator (49) flows into the second intermediate heat exchanger (56) via the liquid crystal pipe (53) via the dryer (54) and then through the capillary tube (55) as a pressure reducing device. do. The gaseous refrigerant separated by the second gas-liquid separator 54 passes through the second intermediate heat exchanger 56 through the gas phase pipe 57, and passes through the third and fourth intermediate heat exchangers 58 and 59. Is cooled and liquefied, and flows into the capillary tube 61 as a decompression device via the dryer 60 through the pipe 68. The capillary tube 61 is connected to the evaporation pipe 62 as an evaporator, and the evaporation pipe 62 is connected to the fourth intermediate heat exchanger 59 through the return pipe 69.

The fourth intermediate heat exchanger 59 is continuously connected to the third, second and first intermediate heat exchangers 58, 56, and 48, and then connected to the suction side pipe 20S of the compressor 20. An expansion tank 65 for storing refrigerant when the compressor 20 is stopped is connected to the suction side pipe 20S through a capillary tube 66 as a pressure reducing device, and the capillary tube 66 is connected to the expansion tank 65. The check valve 67 which made the direction the forward direction is connected in parallel.

As the seven types of mixed refrigerants having different boiling points, the low-temperature side refrigerant circuit 38 is filled with an azeotropic mixed refrigerant including R245fa, R600, R404A, R508, R14, R50, and R740. R245fa is 1,1,1, -3,3-pentafluoropropane (CF ₃ CH ₂ CHF ₂ ) and R600 is butane (CH ₃ CH ₂ CH ₂ CH ₃ ). The boiling point of R245fa is + 15.3 ° C and the boiling point of R600 is -0.5 ° C. Therefore, by mixing these at a predetermined ratio, the boiling point conventionally used can be used as a substitute for R21 of + 8.9 ° C.

In addition, since R600 is a flammable material, it mixes with the non-combustible R245fa in a predetermined ratio and R245fa / R600: 70/30 in this embodiment, and it is enclosed in the refrigerant circuit 38 as non-combustible. In the present embodiment, R245fa is 70% by weight based on the total weight of R245fa and R600, but if it is more than that, it is nonflammable.

R404A is R125 (pentafluoroethane: CHF ₂ CF ₃ ), R143a (1,1,1-trifuloethane: CH ₃ CF ₃ ), and R134a (1,1,1,2-tetrafluoro Ethane: CH ₂ FCF ₃ ), and its composition is 44% by weight of R125, 52% by weight of R143a, and 4% by weight of R134a. The boiling point of the mixed refrigerant is -46.48 ° C. Therefore, the boiling point used conventionally can be used as a substitute for R22 which is -40.8 degreeC.

R508 is composed of R23 (tripulolomethane: CHF ₃ ) and R116 (hexafuluroethane: CF ₃ CF ₃ ), and the composition thereof is 39% by weight of R23 and 61% by weight of R116. The boiling point of the mixed refrigerant is -88.64 ° C.

In addition, R14 is tetrafluoromethane: a (4 fluorocarbon CF _4), and, R50 is methane (CH _4), R740 is argon (Ar). These boiling points are -127.9 degreeC for R14, -161.5 degreeC for R50, and -185.86 degreeC for R740. In addition, although R50 has a risk of explosion due to bonding with oxygen, the risk of explosion is eliminated by mixing with R14. Therefore, even if an accident of leakage of the mixed refrigerant occurs, no explosion occurs.

These refrigerants described above are mixed with R245fa, R600, R14, and R50 in advance in a nonflammable state, and then mixed with R245fa, R600, R404A, R508A, R14, and R50, And R740 are pre-mixed and sealed in the refrigerant circuit. Alternatively, R245fa and R600 are filled, followed by R404A, R5080A, R14 and R50, and finally R740. The composition of each refrigerant is, for example, 10.3% by weight of the mixed refrigerant of R245fa and R600, 28% by weight of R404A, 29.2% by weight of R508A, 26.4% by weight of the mixed refrigerant of R14 and R50, and 5.1% by weight of R740. do.

In addition, in this Example, you may add 4 weight% n-pentane (range of 0.5-2 weight% with respect to the total weight of an azeotropic refrigerant | coolant) in R404A.

Next, the circulation of the refrigerant on the low temperature side will be described. The high-temperature, high-pressure gaseous mixed refrigerant discharged from the compressor 20 flows into the radiator 39 through the discharge side pipe 20D, and is radiated therein to be a oil carrier refrigerant having a high boiling point among the mixed refrigerants and having good oil compatibility. A portion of n-pentane or R600 is condensed and liquefied.

The mixed refrigerant passing through the radiator 39 is introduced into the oil separator 40, and most of the lubricating oil of the compressor 20 mixed with the refrigerant and a part of the refrigerant condensed and liquefied by the radiator 39 (n-pentane). , A part of R600) is returned to the compressor 20 by the oil return pipe 41. As a result, a low boiling point refrigerant having a higher purity flows into the refrigerant circuit 38 at a later stage than the cascade heat exchanger 43, so that ultra low temperature can be efficiently obtained. As a result, even in the compressors 10 and 20 having the same capacity, it is possible to cool the inside of the storage chamber 4, which is a larger volume of the object to be cooled, to a predetermined cryogenic temperature, so that the entire refrigeration apparatus 1 is not enlarged, It becomes possible to aim at increase.

In this embodiment, since the coolant flowing into the oil separator 40 is cooled by the radiator 39 once, the coolant temperature entering the cascade heat exchanger 43 can be lowered. Specifically, it is possible to lower the temperature of the refrigerant flowing into the cascade heat exchanger 43 to about + 65 ° C in the present embodiment to about + 45 ° C.

Therefore, in the cascade heat exchanger 43, it becomes possible to reduce the load on the compressor of the high temperature side refrigerant circuit 25 for cooling the refrigerant in the low temperature side refrigerant circuit 35. In addition, since the coolant in the low temperature side refrigerant circuit 35 can be cooled effectively, the load on the compressor 20 constituting the low temperature side refrigerant circuit 35 can be reduced. Thereby, it becomes possible to implement the improvement of the operating efficiency of the whole refrigerating apparatus 1.

The other mixed refrigerant itself is cooled to about -40 ° C to -30 ° C from the evaporator 34 in the cascade heat exchanger 43 to condense and liquefy some of the high boiling point refrigerants (parts of R245fa, R600, R404A, and R508). do. Then, the mixed refrigerant exiting the condensation pipe 42 of the cascade heat exchanger 43 flows into the first gas-liquid separator 46 via the dryer 44. At this point, R14, R50, and R740 in the mixed refrigerant are in a gaseous state because the boiling point is so low that they are not condensed yet, and only a part of R245fa, R600, R404A, and R508 are condensed and liquefied. 47), R245fa, R600, R404A and R508A are separated by the liquid line 50.

The refrigerant mixture introduced into the gas phase pipe 47 is condensed by heat exchange with the first intermediate heat exchanger 48, and then reaches the second gas-liquid separator 49. Here, the low-temperature refrigerant flowing back from the evaporation pipe 62 flows into the first intermediate heat exchanger 48, and the liquid refrigerant introduced into the liquid pipe 50 flows from the capillary tube 52 through the dryer 51. After depressurizing, it is introduced into the first intermediate heat exchanger 48 and evaporates there, contributing to the cooling, and as a result of cooling some of the uncondensed R14, R50, R740 and R508, the first intermediate heat exchanger 48 The intermediate temperature is about -60 deg. Therefore, R508 in the mixed refrigerant having passed through the gas phase pipe 47 is completely condensed and liquefied to be classified as the second gas-liquid separator 49. R14, R50, and R740 are also gaseous because of their low boiling points.

In the second intermediate heat exchanger (56), the R508 classified in the second gas-liquid separator (49) removes moisture from the dryer (54), depressurizes in the capillary tube (55), and then goes to the second intermediate heat exchanger (56). R14, R50, and R740 in the gas phase pipe 57 are cooled together with the low-temperature refrigerant flowing in and returned from the evaporation pipe 62, and among them, R14 having the highest evaporation temperature is condensed. As a result, the intermediate temperature of the second intermediate heat exchanger 56 is about -90 ° C.

The gas phase pipe 57 passing through the second intermediate heat exchanger 56 then passes through the fourth intermediate heat exchanger 59 via the third intermediate heat exchanger 58. Here, the refrigerant immediately after exiting the evaporator 62 is returned to the fourth intermediate heat exchanger 59, and according to the experiment, the intermediate temperature of the fourth intermediate heat exchanger 59 reaches a temperature as low as -130 ° C. .

For this reason, in the 4th intermediate heat exchanger 59, a part of R50 and R740 in the gas phase piping 57 is condensed, and a part of these liquefied R14, R50 and R740 is removed from the dryer 60, and the capillary tube 61 is removed. After depressurizing, flows into the evaporation pipe 62, where it is evaporated to cool the surroundings. According to the experiment, the temperature of the evaporation pipe 62 at this time became the ultra low temperature of -160.3 degreeC--157.3 degreeC.

Thus, by using the difference of the evaporation temperature of each refrigerant | coolant in the low temperature side refrigerant circuit 38, each intermediate heat exchanger 48, 56, 58, 59 continues to condense the refrigerant | coolant which is still in a gaseous state, and finally, In the stage evaporation pipe 42, an ultra low temperature of -150 ° C or less can be achieved. Therefore, since the said evaporation pipe 62 is wound and heat-exchanged along the heat insulating material 9 side of the inner case 6, the inside of the storage compartment 4 of the refrigerating apparatus 1 has the internal temperature of -152 degrees C or less. It becomes possible to realize.

The refrigerant exiting the evaporation pipe 62 continues to flow into the fourth intermediate heat exchanger 59, the third intermediate heat exchanger 58, the second intermediate heat exchanger 56, and the first intermediate heat exchanger 48, It joins with the refrigerant evaporated by each heat exchanger, and returns to the compressor 20 from the suction pipe 20S.

Most of the oil mixed and discharged from the compressor 20 into the refrigerant is separated by the oil separator 40 and returned to the compressor 20. However, the oil discharged from the oil separator 40 together with the refrigerant is in a mist state. The compressor 20 is returned to the compressor 20 while being dissolved in R600 having high compatibility with oil. Thereby, lubrication defect and lock of the compressor 20 can be prevented. In addition, since R600 returns to the compressor 20 as it is in a liquid state and evaporates in the compressor 20, the discharge temperature of the compressor 20 can be reduced.

As described above, the compressor 20 constituting the low temperature side refrigerant circuit 38 is subjected to on-off control by a control device (not shown) based on the internal temperature of the inside of the storage chamber 4. In this case, when the operation of the compressor 20 is stopped by the control device, the mixed refrigerant in the low temperature side refrigerant circuit 38 passes through the check valve 67 in the forward direction of the expansion tank 65. Is recovered within.

Therefore, the refrigerant in the refrigerant circuit 38 is remarkably and quickly through the check valve 67 as compared with the case where the refrigerant is recovered in the expansion tank 65 through the capillary tube 66 when the compressor 20 is stopped. Can be recovered in the expansion tank 65.

As a result, the pressure in the refrigerant circuit 38 can be prevented from rising, and when the compressor 20 is started by the control device, the refrigerant circuit 38 gradually moves from the expansion tank 65 through the capillary tube 66. By returning the coolant in the middle, the starting load of the compressor 20 can be reduced.

Therefore, by quickly recovering the refrigerant to the expansion tank 65 when the compressor 20 is stopped, the pressure in the refrigerant circuit 38 can be quickly balanced, and the compressor 20 is restarted. At this time, restart of the compressor 20 can be smoothly performed without applying a load to the compressor 20. Thereby, the operation efficiency of the compressor 20 can be improved by remarkably shortening the time required until the equilibrium pressure of the refrigerant circuit 38 at the time of compressor start-up, for example, pull-down operation The time required for this can be shortened, and the convenience can be improved.

On the other hand, in the refrigerant circuit of the refrigerating device 1 as described above, in the evaporation pipe 62 of the low temperature side refrigerant circuit 38, it becomes an ultra low temperature of -160.3 ° C to -157.3 ° C, and the cascade heat exchanger 43 Even at -40 degreeC--30 degreeC, it becomes low temperature. The first intermediate heat exchanger 48 is about -60 ° C, the second intermediate heat exchanger 56 is about -90 ° C, and the third and fourth intermediate heat exchangers 58 and 59 are about -130 ° C. do. Therefore, it is necessary to sufficiently insulate other heat exchangers 43 and the like except for the evaporation pipe 62 disposed in the heat insulating housing 2.

Therefore, these cascade heat exchangers 43 and the 1st, 2nd, 3rd, and 4th intermediate heat exchangers are made into the heat insulation structure 70 which enclosed these by the heat insulating material, and made it rectangular shape. FIG. 7 shows a perspective view of the heat insulation structure 70, and FIG. 8 shows a perspective view of the state in which the heat insulation material of the heat insulation structure 70 is removed.

Here, the detailed structure of the heat insulation structure 70 is demonstrated. In addition, the accumulator 35, the capillary tube 33, and the low temperature side refrigerant circuit 38 constituting the high temperature side refrigerant circuit 25 are added to the portion enclosed by the dotted line in FIG. The dryer 44, the gas-liquid separators 46 and 49, the dryers 51 and 54, and the capillaries 52 and 55 constituting the same constitute the heat insulating structure 70. A cascade heat exchanger 43 is disposed at one end of the heat insulating structure 70, and is positioned to the side of the cascade heat exchanger 43, and each intermediate heat exchanger 48, 56, 58, 59 is arranged in a layered shape. It is.

Each of the intermediate heat exchangers 48, 56, 58, and 59 polymerizes each other by flattening a plurality of stages by winding a relatively large diameter outer pipe in a spiral shape, so that the gas phase pipes 47 and 57 are spaced at an inner side thereof. It is composed of a spiral double pipe structure that passes through the inner pipe. In the present embodiment, the fourth and third intermediate heat exchangers 58 and 59 are arranged in the order of the lowest temperature from the bottom, that is, the second intermediate heat exchanger 56 is disposed thereon, and the first uppermost layer is disposed. An intermediate heat exchanger 48 is arranged.

Then, each of the gas-liquid separators 46 and 49 (in addition, the second gas-liquid separator 49 is not shown in FIG. 8) inside the intermediate heat exchanger or around the cascade heat exchanger 43, and the dryers 44 and 51. 54 (not shown in Fig. 8), capillaries 33, 52, 55 and the accumulator 35, which are not shown, are disposed to reduce the dead space, thereby miniaturizing the dimensions.

In the heat insulating structure 70 of the present embodiment, the cascade heat exchanger 34 includes a pipe connecting the device arranged in the heat insulating structure 70 and the device arranged outside the heat insulating structure 70. It is arrange | positioned facing the one end side surface on the opposite side to the arrange | positioned side. Specifically, the discharge side piping 10D after passing through the condenser 31 of the high temperature side refrigerant circuit 25 connected to the cascade heat exchanger 34, the suction side piping 10S connected to the compressor 10, Similarly, the discharge side pipe 20D after passing through the oil separator 40 of the low temperature side refrigerant circuit 38 connected to the cascade heat exchanger 34, the suction side pipe 20S connected to the suction side of the compressor 20, A pipe 68 connected from the gas phase pipe 57 disposed in the fourth intermediate heat exchanger 59 to the evaporation pipe 62 and a return connected to the fourth intermediate heat exchanger 59 from the evaporation pipe 62. The connection part of each piping of the piping 69 is arrange | positioned intensively on one side surface of the heat insulation structure 70.

At this time, the suction side pipes 10S and 20S and the discharge side pipe 20D through which the refrigerant having a relatively high temperature flows are gathered to the outside, and in the present embodiment, the heat insulating structure 70 is installed in the heat insulating housing 2. And the piping 68 connected to the evaporation pipe 62 and connected to the evaporation pipe 62, and the return pipe 69 through which the cryogenic refrigerant flows, and the opposite side to the suction side pipe 10S and the like. In the present embodiment, the heat insulation structure 70 is disposed toward the heat insulation housing 2 side in a state where the heat insulation structure 70 is provided in the heat insulation housing 2. In addition, the dryer 60 and the capillary tube 61 connected to the pipe 68 are disposed outside the heat insulating structure 70.

9 shows the back side perspective view of the refrigerating device 1. As shown in FIG. The refrigeration apparatus 1 is formed with a rectangular opening 71 extending in the front-rear direction and opening rearward on a side wall of the heat insulating housing 2 located on the machine room 3 side. Corresponding to 71, a notch 72 is also formed at the rear side of the side wall on the machine room 3 side. The heat insulating structure 70 as described above is inserted into the opening 71 from the back side of the heat insulating housing 2. At this time, the heat insulation structure 70 is inserted into the opening 71 from the side where the cascade heat exchanger 34 is arrange | positioned, and by this, each piping 10S, 20S, which extends and is arrange | positioned to one side of the heat insulation structure 70, 20D, 68, 69 and the pipe 10D to which the capillary tube 33 of the high temperature side refrigerant circuit 25 is connected are faces in the direction in which the heat insulating structure 70 is inserted and separated, and in this embodiment, the heat insulating housing 2. Face the back of the.

Therefore, after installing apparatuses, such as the compressors 10 and 20, in the machine room 3, the heat insulation structure 70 is finally inserted in the opening 71, and the piping 68 and 69 are heat-insulated in that state. Piping connection is carried out to the evaporation pipe 62 provided in the (2) side, and piping 10S, 10D, 20S, 20D is connected to the machine of the machine room 3 side. Thereby, the apparatus which comprises the said heat insulation structure 70, the apparatus, such as the evaporation pipe 62 arrange | positioned in the heat insulation housing 2, the compressors 10 and 20 arrange | positioned in the machine room 3, and a heat insulation housing It becomes possible to connect piping easily from the back of (2), and it becomes possible to aim at the improvement of piping workability and assembly workability. Moreover, even when each apparatus which comprises the said heat insulation structure 70 breaks down, it is easy by taking out the heat insulation structure 70 to the direction other than the side in which the heat insulation housing 2 and the machine room 3 are comprised. It is possible to execute maintenance work.

And a part of the back surface which each piping of the said heat insulation structure 70 is extended, and the side surface facing the machine room 3 side is occluded by the cover member 73 bent by the substantially L shape of cross section. In this case, a heat insulating plate (not shown) loaded with glass wool or the like may be disposed in the gap formed between the heat insulating structure 70 and the side surface of the machine room 3 side.

According to the configuration as described above, the cascade heat exchanger 43 or each intermediate heat exchanger (48, 56, 58, 59) of the heat insulating housing (2) in the state of the heat insulating structure 70 formed integrally by the heat insulating material Since it is arrange | positioned at the side wall of the machine room 3 side, compared with the case where the said heat insulation structure 70 is installed in the back part of the heat insulation housing 2 like conventionally, it becomes possible to reduce the depth dimension of the whole refrigeration apparatus 1 whole. .

Therefore, the problem that the depth dimension of the whole apparatus 1 becomes large by the presence of the protrusion part by the heat insulation structure 70 for enclosing the cascade heat exchanger 43 etc. can be avoided, and it is high temperature in high temperature like this embodiment. Even in a refrigeration apparatus having a temperature of -150 ° C. or less, for example, it is possible to suppress the entire depth dimension to about 765 mm while securing about 495 mm of the depth dimension in the refrigerator, whereby a normal inlet (generally about 800 It is possible to avoid the problem of being blocked in about mm). In particular, since the heat insulation structure 70 can be withdrawn from a general carrying-in opening in the state installed in the apparatus 1, it becomes unnecessary to separate and connect the heat insulation structure 70 from a main body in the installation place. This makes it possible to avoid troublesome work.

This makes it possible to easily carry in and out of the refrigerating device 1 without significantly reducing the storage volume in the refrigerator. Moreover, also in the installation place, since the heat insulation structure 70 for enclosing the said cascade heat exchanger 43 etc. does not protrude toward the outer side from the back surface, it becomes possible to narrow the area required for installation.

Moreover, since the cascade heat exchanger and the heat insulation structure for enclosing the periphery of each intermediate heat exchanger are not provided in the back surface of the heat insulation housing 2 like conventionally, the heat insulation housing 2 comprised by facing outside as mentioned above is mentioned. It is possible to arrange the vacuum insulation panel 12 in the front wall 6A of the back wall 6B and the side wall 6C on the opposite side of the machine room, so that the inside of the storage compartment 4 is, for example, -150 ° C or less. Even when it becomes the same ultra low temperature, it becomes possible to improve the heat insulation performance of the heat insulation housing 2 itself. Therefore, size reduction can be aimed at, and even if it is the same external dimension as before, it becomes possible to enlarge the storage volume in the storage chamber 4. Or even if it is the same storage volume as the conventional one, it becomes possible to reduce an external dimension, and also by this, it becomes possible to narrow the area for the installation of the refrigeration apparatus 1 required.

In addition, in this embodiment, although the heat insulation structure 70 can be inserted and separated in the side wall of the heat insulation housing 2 from the back of the refrigeration apparatus 1, ie from the back side, it is not limited to this, For example, heat insulation You may make it insertable and removable from the front of the housing 2, or from upper direction. Thereby, similarly to the present embodiment, the cascade heat exchanger 43 and each intermediate heat exchanger 48 and the like, which are integrated as the heat insulating structure 70, can be easily assembled into the main body of the apparatus 1, and assembling workability is achieved. Can improve.

In addition, similarly to the present embodiment, by pulling the heat insulating structure 70 forward or upward, it is possible to take it out of the main body of the apparatus 1, so that the cascade heat exchanger 43 or each of the parts constituting the heat insulating structure 70 can be taken out. It is possible to easily perform maintenance work such as the intermediate heat exchanger 48.

In addition, in this embodiment, although the heat insulation structure 70 comprises the cascade heat exchanger 43, each intermediate heat exchanger 48, etc. which comprise the said refrigeration apparatus 1 integrally, cascade heat exchange is other than this. Only the group 43 or each intermediate heat exchanger 48 or the like may be integrally formed as the heat insulating structure 70 and arranged to be inserted into and detachable from the side wall of the heat insulating housing 2 as in the present embodiment.

In addition, in the present embodiment, the refrigerant circuit constituting the refrigerating device 1 condenses the refrigerant discharged from the compressor 10 or 20, respectively, and then evaporates to exert a cooling action to form an independent refrigerant closed circuit. Circuit 25 and a low temperature side refrigerant circuit 38, wherein the low temperature side refrigerant circuit 38 includes the compressor 20, the condensation pipe 42, the evaporation pipe 62, and the evaporation pipe 62. A plurality of, in particular, four intermediate heat exchangers 48, 56, 58, 59 connected in series so that the return refrigerant flows, and a plurality of capillaries 42, 55, 61, in particular, A species of azeotropic mixed refrigerant is enclosed and condensed refrigerant in the refrigerant via the condensation pipe 42 is joined to each intermediate heat exchanger through each capillary tube, and the uncondensed refrigerant in the refrigerant is cooled in the intermediate heat exchanger. Condensation of low boiling point refrigerant 61, the refrigerant having the lowest boiling point is introduced into the evaporation pipe 62, and at the same time, the cascade heat exchanger (e.g., the evaporator 34 of the high temperature side refrigerant circuit 25 and the condensation pipe 42 of the low temperature side refrigerant circuit 38) is introduced. 43 is described, and it is demonstrated as the refrigeration apparatus 1 of the two-stage multistage system which obtains ultra low temperature by the evaporation pipe 42 of the low temperature side refrigerant circuit 38, However, this invention is not limited to this.

That is, for example, the high-temperature side refrigerant circuit and the low-temperature side refrigerant circuit constituting the independent refrigerant closed circuit for condensing and evaporating the refrigerant discharged from the compressor, respectively, to exert a cooling action, and the evaporator of the high-temperature side refrigerant circuit Even if the cascade heat exchanger is constituted by the condenser of the low temperature side refrigerant circuit, and the refrigerating device of the simple multi-way (two-way) type system which obtains ultra low temperature by the evaporator of the low temperature side refrigerant circuit, the cascade heat exchanger 43 is similar to this embodiment. Likewise, the same effect can be obtained by forming in the heat insulation structure 70 and making it possible to insert and separate the said heat insulation structure 70 in the side surface of the machine room 3 side of the heat insulation housing 2. As shown in FIG.

Similarly, a plurality of intermediate heat exchangers and a plurality of depressurization devices connected in series so as to distribute a compressor, a condenser, an evaporator, and a return refrigerant from the evaporator, and a plurality of non-azeotropic mixed refrigerants are encapsulated to pass through the condenser. The condensed refrigerant in one of the refrigerants is joined to the intermediate heat exchanger via a decompression device, and the non-condensed refrigerant in the refrigerant is cooled by the intermediate heat exchanger to condense the refrigerant having a lower boiling point than the sequence, and the lowest pressure is reduced through the decompression device in the final stage. Even in a simple multi-stage refrigerating device that obtains ultra low temperature by introducing a boiling point refrigerant into an evaporator, each intermediate heat exchanger is configured in the heat insulating structure 70 as in the present embodiment, and the heat insulating structure 70 is formed in the machine room of the heat insulating housing 2. The same effect can be acquired by making insertion insertion removal possible to the side surface of (3) side.

Claims (4)

A refrigeration apparatus comprising a refrigerant circuit composed of a compressor, an evaporator, and the like, wherein the storage compartment configured in the heat insulating housing is cooled by an evaporator at an extremely low temperature. It is provided in the side of the said heat insulation housing, Comprising: The refrigeration apparatus characterized by including the machine room in which the said compressor etc. are installed, and the measuring hole communicated in the said storage room in the side wall of the said machine room side of the said heat insulation housing. The said heat insulating housing is formed in the composite structure of a vacuum heat insulating panel and a foam heat insulating material, and the said vacuum heat insulating panel is arrange | positioned in the front and back walls of the said heat insulating housing, and the side wall opposite to the said machine room, It is characterized by the above-mentioned. Refrigeration unit. The refrigeration apparatus according to claim 1 or 2, wherein an opening and closing panel for concealing the measurement hole is provided in the machine room. A refrigeration apparatus according to claim 3, wherein the ceiling panel of the machine room is configured to be openable and open, and the measurement hole is made operable with the ceiling panel open.

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