JPS6261856B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for exhausting a cooling device, and is particularly aimed at evacuating a refrigerant circuit in a short time and reducing the number of locations at risk of refrigerant leakage.

Conventionally, the exhaust method for this type of cooling device was
As described in Publication No. 40392, in order to exhaust the inside of the refrigerant circuit, an exhaust pipe is connected between the service pipe installed on the compressor and the service pipe installed on the inlet side of the dryer. There are two methods: one is to connect an exhaust pump to the service pipe of the compressor, fill nitrogen gas in the refrigerant circuit, replace it with air, and then exhaust the air. During use, the number of locations where refrigerant can leak increases due to welding deterioration, etc., which increases maintenance and inspection work and complicates the structure, which is undesirable, and in the latter case, exhaust work is complicated. Moreover, since both of them are exhausted through a capillary reach tube, this capillary reach tube acts as a resistance, making it take a long time to exhaust the air by the exhaust pump, and the capillary reach tube is easily clogged with dust such as processed metal powder.

The present invention has been made in view of the above-mentioned points, and is provided with a side pipe in the refrigerant circuit that directly flows high-temperature refrigerant to the evaporator, and a solenoid valve for controlling the flow of the side pipe for controlling the flow of the compressor. There is an exhaust method in which the solenoid valve is energized to open when the refrigerant circuit is exhausted, and an exhaust pump is used to exhaust the air from the service pipe of the compressor.This method reduces the capillary resistance. In addition, the piping is simplified, and there are few special additional configurations, the structure is simple, and the cost is low. It is even more effective when using refrigerant gas.

Embodiments of the method of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a cooling device body used for any purpose such as science and science experiments, and is equipped with objects to be cooled such as a cooling tank 3 installed in an exterior body 2, and a refrigerant cycle 4 for cooling this cooling tank 3. are doing. This refrigerant cycle 4 includes a refrigerant compressor 5, a condenser 6, a first gas-liquid separator 7, a first heat exchanger 8, a second gas-liquid separator 9, a second
It is configured by sequentially connecting a heat exchanger 10, a subcooler 11, a capillary reach tube 12, an evaporator 13, etc., and it is configured by connecting a heat exchanger 10, a supercooler 11, a capillary reach tube 12, an evaporator 13, etc.
-21, R-13B, R-14, etc.) are mixed and sealed. The first gas-liquid separator 7 has a refrigerant pipe 14 from the condenser 6 passed through the side of the hollow cylindrical outer cylinder, and is connected to the upper part of the refrigerant pipe leading to the first heat exchanger 8. 15 are connected to each other, and a conduit 18 communicating with a capillary reach tube 17 via a dryer 16 or the like is connected to the lower part thereof. The second gas-liquid separator 9 has its side facing through the other end of a discharge pipe 19 whose one end is connected to the first heat exchanger 8, and communicates with the upper part thereof to the second heat exchanger 10. A refrigerant pipe 20 is connected to the refrigerant pipe 20, and a conduit 23 communicating with a capillary reach tube 22 is connected to the lower part via a dryer 21 and the like. Discharge pipe 2 from the second heat exchanger 10
4 is connected to the supercooler 11. The suction pipe 25 leading from the evaporator 13 to the refrigerant compressor 5 is bent in a meandering manner at the heat exchanger 10, 8 portion formed in communication with the evaporator 13, or is provided with heat exchanger fins to absorb the heat. The capillary reach tube 17 is disposed in a communicating heat exchange relationship with the exchangers 10 and 8, respectively, and is located at an appropriate position on the side of the evaporator 13 from the first heat exchanger 8.
and the capillary reach tube 22 are connected to each other at appropriate positions closer to the evaporator 13 than the second heat exchanger 10.

The outlet of the condenser 6 and the inlet of the evaporator 13 are communicated through a bypass pipe 27 whose flow is controlled by a solenoid valve 26, and the refrigerant compressor 5 is opened by energizing and opening the solenoid valve 26. More pressurized high temperature refrigerant,
After passing through the condenser 6, it is directly supplied to the evaporator 13, and the evaporator 13 is heated to heat and melt the frost and ice attached to the cooling tank 3 of the main body 1. The refrigerant compressor 5
A service pipe 28 is provided which opens into the airtight container and is closed by crushing or the like after the cooling device 1 is completed.

The operation of the refrigerant cycle 4 includes a plurality of types (three types in the embodiment) of the refrigerant compressed by the refrigerant compressor 5.
The mixed refrigerant radiates heat in the condenser 6, and the refrigerant having a high evaporation temperature liquefies, and flows into the first gas-liquid separator 7 through the refrigerant pipe 14 together with other refrigerants that are still gaseous.
The gas-liquid mixed refrigerant spouted into the first gas-liquid separator 7,
Gaseous refrigerant with a low evaporation temperature (R-
Two types of mixed gas refrigerants (13B and R-14) flow through the refrigerant pipe 15 to the first heat exchanger 8. On the other hand, the liquid refrigerant dripped into the inner bottom of the control first gas-liquid separator 7 is dehumidified through the conduit 18 and the dryer 16, and is depressurized in the capillary reach tube 17 and connected to the first heat exchanger 8 through a suction pipe connected to heat exchange. At 25, the first
Cool the heat exchanger 8. As a result, the refrigerant gas having a high evaporation temperature among the mixed refrigerant gases that have passed through the first gas-liquid separator 7 and flowed into the first heat exchanger 8 is condensed and liquefied. Then, the gas-liquid mixed refrigerant flows from the first heat exchanger 8 into the second gas-liquid separator 9, and the gas-liquid mixture refrigerant flows into the first gas-liquid separator 7.
Similarly, the second gas-liquid separator 9 separates the gaseous refrigerant with a low evaporation temperature (e.g. R-14) and the liquid refrigerant liquefied in the first heat exchanger 8 (e.g. R-13B), and the gas The liquid refrigerant is sent to the second heat exchanger 10, and the liquid refrigerant is dehumidified through the conduit 23 through the dryer 21, depressurized in the capillary reach tube 22, and evaporated in the suction pipe 25 connected to the second heat exchanger 10. to cool down the second heat exchanger 10. At this time, since the refrigerant that liquefies in the first heat exchanger 8 has a lower evaporation temperature than the refrigerant that liquefies in the condenser 6, the second heat exchanger 10
The gaseous refrigerant separated and supplied from the gas-liquid separator 9 is cooled to a lower temperature than the first heat exchanger 8 in the second heat exchanger 10, condensed and liquefied, and sent to the supercooler 11 through the discharge pipe 24. The low temperature (for example -20
It is supercooled with the return refrigerant at a temperature of around -80℃.
A second heat exchanger 1 is installed inside the hollow cylinder of this supercooler 11.
The refrigerant with the lowest evaporation temperature (refrigerant R-14 in the example), which has flown in through the second heat exchanger 10, is a gas-liquid mixed refrigerant that contains gaseous refrigerant and cannot be completely liquefied by cooling in the second heat exchanger 10. The gaseous refrigerant floats and accumulates in the upper part of the hollow cylinder, and the liquid refrigerant is supercooled in the heat exchanger part of the suction pipe 25 exposed inside the hollow cylinder, and then flows through the refrigerant pipe 29 and capillary reach tube 12 from the discharge port. It is supplied to the evaporator 13 via the evaporator 13. On the other hand, since the gaseous refrigerant floating in the upper part of the hollow cylinder is in contact with the heat exchanger part of the suction pipe 25 through which the low-temperature refrigerant flows immediately after flowing out from the evaporator 13, it is cooled and the outer surface of the heat exchanger part is cooled. The refrigerant condenses, flows down along the vertically extending heat exchanger, or drops directly, joins the liquid refrigerant accumulated at the bottom of the hollow cylinder, and flows out from the discharge port. The evaporator 13 is evaporatively cooled using the refrigerant with the lowest evaporation temperature that passes through the supercooler 11 and reaches the capillary reach tube 12. Use it by putting it in. In the experiment, the three types of refrigerants R-21, R-13B, and R-14 were used in the cooling tank 3.
A cooling temperature of -80℃ to -90℃ was obtained.

In the above embodiments, three types of refrigerants were used, but two or four or more types may be used. At this time, the number of gas-liquid separators and heat exchangers increases or decreases depending on the type of refrigerant. Further, the bypass pipe 27 may be arranged not after the condenser 6 but after the refrigerant compressor 5 and before the condenser 6 to supply high-temperature refrigerant to the evaporator 13.

The cooling tank 3 of the main body 1 faces the other end of a hollow passage 31 formed of a tubular body, one end of which communicates with a storage container 30 for storing biological substances A, etc., and a suction pipe 33 of a vacuum pump 32. The air inside the storage container 30 is sucked through the cooling tank 3 by the vacuum pump 32, and the inside of the storage container 30 is evacuated to remove the pre-frozen biological substances A, etc. So-called freeze-drying. At this time, the moisture contained in the air from the storage container 30 passing through the cooling tank 3 is -
Air that is frozen on the inner peripheral wall of the cooling tank 3 cooled to an extremely low temperature such as 80° C. to -90° C. and is almost dehumidified is drawn to the vacuum pump 32 and discharged into the atmosphere from the exhaust pipe 34.

Next, the third
The electric circuit shown in the figure will be explained.

The vacuum pump 32 is connected to a power terminal 35 via a power switch 36 along with a blower 37 for forcing air through the condenser 6, a solenoid valve 26, a refrigerant compressor 5, and the like. The solenoid valve 26 is connected in series to a hot gas switch 3 that opens and closes manually or automatically, such as with a timer.
8 to the power terminal 35 at a stage earlier than the power switch 36, and the relay coil 39
are connected in parallel. Reference numeral 40 denotes a relay coil for controlling the switching switch 41, which is connected to the power supply terminal 35 via a temperature switch 42 that opens and closes by sensing the temperature of the cooling tank 3 and the like. The refrigerant compressor 5 is connected to the switching piece c of the switching switch 41, which is composed of a first contact a, a second contact b, and a switching piece c, and when the relay coil 40 is energized, the first contact is connected to the switching piece c through the switching piece c. a
When the power is de-energized, it is connected to the second contact b via the switching piece c. 43 is a normally closed switch whose opening and closing are controlled by the relay coil 39, one end of which is connected between the power switch 36 and the temperature switch 42, and the other end of which is connected to the second contact b of the switching switch 41. . 44
is an overload switch for the refrigerant compressor 5.

With the above-mentioned configuration, the refrigerant cycle 4 is exhausted by connecting the exhaust pump 45 to the service pipe 28 of the refrigerant compressor 5, connecting the power terminal 35 of the main body 1 to the power source, and connecting the hot The gas switch 38 is forcibly closed. This opens the solenoid valve 26 and communicates with the side pipe 27, so when the exhaust pump 45 is operated, the refrigerant flows through a pipe body with a large diameter such as the side pipe 27 without passing through the capillary reach tube 12. Air in the refrigerant cycle 4 is sucked into the compressor 5 and exhausted by the exhaust pump 45 via the service pipe 28. Capillary reach tube 12
The air in and near the evaporator 1 and 17 and 22 is also
3 and the condenser 6 to the refrigerant compressor 5, and are sucked into the intake air flowing through the pipe body with a large diameter, and are exhausted by the exhaust pump 45, and the amount thereof is small compared to the total air in the refrigerant cycle 4. , and has little to do with evacuation time extension. After the exhaust is completed, refrigerant gas is filled in and the service pipe 28 is closed by crushing or the like to complete the process.

The subsequent operation of the cooling device 1 is performed by switching the power switch 36 when the cooling tank 3 is cooled by the evaporator 13.
When inputting, 35-36-43-b-c-5-
A closed circuit 44-35 is formed, the refrigerant compressor 5 is operated, and cooling by the evaporator 13 is started. When the temperature falls below a predetermined temperature (for example, about 2°C), the temperature switch 42 closes and the relay coil 40 is attached. The switching piece c is switched from the second contact b to the first contact a to continue operating the refrigerant compressor 5, and the cooling tank 3 is heated from -80°C to -
Cool to an extremely low temperature such as 90℃. Then storage container 30
When the hollow passage 31 faces the inside of the cooling tank 3, the air inside the storage container 30 is sucked and exhausted through the cooling tank 3 by the vacuum pump 32 in operation, and the frozen biological substances inside the storage container 30 are removed. Dry A etc. by sublimation.

After a predetermined period of operation, a large amount of moisture adheres to the inner peripheral wall of the cooling tank 3 and freezes, so when the hot gas switch 38 is closed automatically or manually after checking visually, the solenoid valve 26 is opened and the refrigerant compressor is closed. After passing through the condenser 6, the refrigerant from No. 5 flows directly into the evaporator 13, where it is heated and melts the frost and ice attached to the peripheral wall of the cooling tank 3. When the melting of the frost and ice progresses and the temperature inside the cooling tank 3 rises to a predetermined temperature, for example, about 10°C, the temperature switch 42 opens, the relay coil 40 is deenergized, and the switching piece c of the switching switch 41 is switched from the first contact a. Switching back to the second contact b. At the same time, the relay coil 39 in parallel with the solenoid valve 26 remains energized due to the closing of the hot gas switch 38, and the normally closed switch 43 remains energized.
continues to open, the refrigerant compressor 5 stops,
Refrigerant flow in the refrigerant cycle 4 is stopped. Therefore, the residual frost on the inner circumferential wall of the cooling tank 3 is gradually melted at room temperature. When the frost and ice on the inner circumferential wall of the cooling tank 3 are completely melted and removed, the hot gas switch 38 is opened visually or automatically, and the solenoid valve 26 is closed and the relay coil 39 is deenergized. is closed, and the refrigerant compressor 5 is operated again to resume cooling of the cooling tank 3.

While the refrigerant compressor 5 is stopped, the high and low pressures of the refrigerant cycle 4 can be adjusted via the side pipe 27, and damage such as valve breakage and motor burnout due to overload on the refrigerant compressor 5 when restarted can be avoided. Ru. Preferably, the vacuum pump 32 is connected in series with a control switch 46 to arbitrarily control its operation.

Since the present invention performs exhaust in the refrigerant cycle using the method described above, the service pipe of the refrigerant compressor can be used for exhaust, the structure is simple, and the number of locations at risk of refrigerant leakage does not increase. Moreover, most of the exhaust during the refrigerant cycle can be done through the large-diameter pipe body without using the capillary reach tube, which shortens the exhaust time and prevents dust such as metal powder from entering the capillary reach tube. The risk of clogging is also significantly reduced. In addition, this operation can be performed by opening the solenoid valve of the side pipe provided for heating the hot gas of the evaporator, which simplifies the structure with almost no special additional configuration required, and is easy to handle. It becomes easier. Furthermore, there will be no problems after the cooling system is completed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a cooling device completed by the method of the present invention, Fig. 2 is a schematic diagram of the refrigerant cycle, Fig. 3 is a schematic electrical circuit diagram, and Fig. 4 is a partially cutaway cross-section showing an example of its use. It is a schematic block diagram. 5... Refrigerant compressor, 26... Solenoid valve, 27...
Side pipe, 28...service pipe, 45...exhaust pump.

Claims (1)

[Claims] 1 A refrigerant cycle consisting of a refrigerant compressor, a condenser, a capillary reach tube, an evaporator, etc. is provided with a side pipe whose communication is controlled by a solenoid valve that directly supplies high-temperature refrigerant to the evaporator, and this solenoid valve is connected to the An exhaust pump is connected to a service pipe connected upstream of a power switch for the refrigerant compressor and communicated with the airtight container of the refrigerant compressor, and the electromagnetic valve is energized and opened. Connect the pipes,
A method for exhausting a cooling device, which operates the exhaust pump to exhaust air from a refrigerant cycle.