JP2711878B2 - Low temperature refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigeration apparatus using a compressor, and more particularly to a refrigeration apparatus for obtaining a low temperature using a plurality of types of non-azeotropic refrigerant mixtures.

[Conventional technology]

In the mixed refrigeration cycle, the mixed refrigerant is liquefied and separated step by step in the order of the high-boiling refrigerant and is adiabatically expanded, whereby the low-boiling refrigerant can be sequentially condensed to obtain a low temperature.

A known mixed refrigeration cycle will be described with reference to FIG.
In FIG. 2, the mixed refrigerant is adiabatically compressed by a compressor 1, and the adiabatic compressed refrigerant is cooled by cooling water or the like in a condenser 2 and partially condensed. At 3, heat is exchanged with the return refrigerant from the low-temperature part, and after being partially condensed, the first separator 4 separates the refrigerant into condensed refrigerant and uncondensed refrigerant. The separated condensed refrigerant is adiabatically expanded by the first expansion valve 5 to generate a low temperature, merges with the return refrigerant from the low temperature part, flows through the first heat exchanger 6, and is separated by the first separator. The uncondensed refrigerant thus cooled is further cooled and partially condensed. By sequentially repeating this, the refrigerant having a lower boiling point is sequentially condensed and adiabatically expanded, whereby a lower-temperature refrigerant gas can be generated.

Also, in the above-mentioned mixed refrigeration cycle, a low-temperature refrigerant and a high-temperature refrigerant are switched and supplied (US Pat. No. 4,535,595).
The method of No. 7 is described with reference to FIG. The refrigeration cycle is as described above with reference to FIG. A low-temperature refrigerant coil 21 for flowing a low-temperature refrigerant to the load cooler 14
And a high-temperature refrigerant coil 22 for passing high-temperature refrigerant. The refrigerant gas from which the liquefied refrigerant and the refrigerating machine oil have been separated and eliminated by the first separator 4 is led to a high-temperature heat exchanger 23 provided on the discharge side of the compressor 1 and heat-exchanged with the adiabatic-compressed high-temperature feed refrigerant 16, The high-temperature refrigerant coil 22 flows. Opening / closing valves 19 and 20 are provided in the flow paths for supplying the low-temperature refrigerant and the high-temperature refrigerant, respectively, to perform a switching operation.

Further, another known method (U.S. Pat. No. 4,597,267) will be described with reference to FIG. 4. The low-temperature refrigerant supply cycle is as described above with reference to FIG. The high-temperature refrigerant supply cycle will be described with reference to FIG. Close the low-temperature refrigerant supply valve, open the high-temperature refrigerant supply valve,
After the refrigerant gas that has exited the final separator 10 undergoes heat exchange with the refrigerant return gas in the low-temperature heat exchanger 24, heat exchange is performed with the adiabatic-compressed high-temperature refrigerant on the discharge side of the compressor 1 and the high-temperature heat exchanger 23. After the temperature is raised, it is supplied to the load cooler 14. In this way, the low-temperature refrigerant and the high-temperature refrigerant are switched and supplied.

[Problems to be solved by the invention]

In the mixed refrigerant refrigeration cycle described above, when switching from the low-temperature refrigerant supply cycle to the high-temperature refrigerant supply cycle, the high-temperature refrigerant flows in each heat exchanger cooled to low temperature, and the liquefied refrigerant is rapidly vaporized. And the internal pressure rises abnormally. For this reason, the gas flow in the machine may be blocked, the discharge pressure of the compressor may rise abnormally, and the compressor may be overloaded, and the operation may not be continued. For this reason, the high-temperature refrigerant supply cycle usually has to be limited to about 1 to 2 minutes.

When a normal temperature section such as a compressor and a condenser is separated from a low temperature section such as an intermediate heat exchanger and a separator, the refrigerant gas in the low temperature section is transferred to the high temperature heat exchanger in the normal temperature section. It is necessary to construct a pipe for guiding and sending it to the load cooler on the low temperature part side. This not only imposes a heavy burden on the construction, but also causes a pressure loss in the refrigerant circulation, and places a heavy burden on the compressor.

Therefore, the present invention provides a refrigeration system that solves the above-described problems, has relatively simple piping construction, can easily switch between a low-temperature refrigerant and a high-temperature refrigerant, and does not burden the device even when operated for a long time. The purpose is to:

[Means for solving the problem]

The above-described object is to provide a first refrigerant supply passage through which the lowest-temperature refrigerant flows through the load cooler through the final-stage pressure reducing valve, and, in parallel with this, a relatively high temperature from the sending refrigerant side of the intermediate heat exchanger. And a second refrigerant supply passage for allowing the refrigerant to flow through the load cooler, and providing an on-off valve in each refrigerant supply passage to switch and supply the lowest temperature refrigerant and the relatively high temperature refrigerant. .

That is, the present invention provides a compressor, a condenser, a load cooler,
A plurality of stages of intermediate heat exchangers, in which a feed refrigerant on the compressor discharge side and a return refrigerant from the load cooler flow, a plurality of separators and a decompressor, and a plurality of types of non-azeotropic mixing Using a refrigerant, the condensed refrigerant of the refrigerant that has passed through the condenser is separated by a separator, merges with the return refrigerant from a lower temperature that has passed through the load cooler through the decompressor, and has not been condensed in the intermediate heat exchanger. In a refrigeration system that cools a refrigerant and sequentially condenses a refrigerant having a lower boiling point and circulates the condensed refrigerant to the load cooler through the decompressor, the lowest temperature is supplied through a final stage decompressor. And a first refrigerant supply passage through which the refrigerant flows through the load cooler, and heat exchange between the refrigerant having a relatively higher temperature than the intermediate heat exchanger and the intermediate heat exchanger without passing through the final stage decompressor. And a second refrigerant supply channel for flowing through the load cooler without performing Each on-off valve provided in the medium supply channel and the second coolant supply passage, the switching between a relatively high-temperature refrigerant and coldest refrigerant in refrigeration apparatus which can supply to the load cooler.

(Operation)

By using the low-temperature refrigeration apparatus of the present invention, the lowest temperature refrigerant and the relatively high-temperature low-temperature refrigerant can be easily switched and supplied to the load cooler. In addition, stable operation can be performed without the compressor being overloaded due to the switching of the supply refrigerant temperature.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The present invention is not limited to these examples.

Example 1 FIG. 1 shows a low-temperature refrigeration system using a non-azeotropic refrigerant mixture for switchingly supplying a low-temperature refrigerant and a relatively high-temperature refrigerant. The mixed refrigerant is adiabatically compressed by the compressor 1, the adiabatic compressed refrigerant is cooled by cooling water or the like in the condenser 2 and partially condensed, and the gas-liquid mixed refrigerant is cooled by the auxiliary heat exchanger 3 from the low-temperature portion. Heat exchange with the return refrigerant, further promote partial condensation,
The first separator 4 separates the condensed refrigerant from the uncondensed refrigerant. The separated condensed refrigerant generates a low temperature by being adiabatically expanded by the first expansion valve 5, merges with the return refrigerant from the low temperature part, flows through the first heat exchanger 6, and passes through the first separator. The separated uncondensed refrigerant is further cooled and partially condensed. By repeating this in sequence, a low temperature can be obtained.

To get the lowest temperature, use a low-temperature refrigerant supply solenoid valve.
19 is opened, the high-temperature refrigerant supply solenoid valve 20 is closed, and the refrigerant is supplied to the load cooler 14 through the last-stage expansion valve 13 by the refrigeration cycle. When a relatively high-temperature refrigerant is to be obtained, the high-temperature refrigerant supply solenoid valve 20 is opened, the low-temperature refrigerant supply solenoid valve 19 is closed, and the refrigerant is supplied to the load cooler 14 from an intermediate stage of the refrigeration cycle. In this manner, by switching the solenoid valve, it is possible to switch and supply between a low-temperature refrigerant supply and a relatively high-temperature refrigerant supply.

Then, when the present refrigeration apparatus is used for a vacuum exhaust device, freezing and exhausting and regeneration can be suitably performed.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the low-temperature refrigeration apparatus of this invention, piping construction is comparatively easy, a low-temperature refrigerant | coolant and a high-temperature refrigerant | coolant can be switched easily, and operation | movement is possible, and even if it operates for a long time, a load is not put on an apparatus.

Further, if the load cooling section of the low-temperature refrigeration apparatus is incorporated into a vacuum exhaust device and the vacuum exhaust is performed, the cooling surface can be continuously regenerated.

[Brief description of the drawings]

FIG. 1 is a route diagram showing one embodiment of the present invention, FIG.
FIG. 4 is a route diagram showing a known low-temperature refrigeration apparatus. 1 ... Compressor, 2 ... Condenser, 3 ... Auxiliary heat exchanger, 4
... 1st separator, 5 ... 1st expansion valve, 6 ... 1st heat exchanger, 7 ... 2nd separator, 8 ... 2nd expansion valve, 9 ... 2nd
Heat exchanger, 10 third separator, 11 third expansion valve, 12
... 3rd heat exchanger, 13 ... last stage expansion valve, 14 ... load cooler, 15 ... tank, 16 ... sending refrigerant, 17 ... returning refrigerant, 18 ... 4th expansion valve, 19 ... Low temperature refrigerant supply solenoid valve, 20
…… High temperature refrigerant supply solenoid valve, 21 …… Low temperature refrigerant supply piping, 22
…… High-temperature refrigerant supply piping,

Claims (1)

(57) [Claims] 1. A compressor, a condenser, a load cooler, a plurality of intermediate heat exchangers for passing a refrigerant sent from the compressor discharge side and a return refrigerant from the load cooler, a plurality of separators, and a decompression device. Equipped with a plurality of types of non-azeotropic refrigerant mixture, the condensed refrigerant of the refrigerant passed through the condenser is separated by a separator, from the lower temperature portion passed through the load cooler through the decompressor Return refrigerant, cools the uncondensed refrigerant in the intermediate heat exchanger, sequentially condenses the refrigerant having a lower boiling point, and circulates the condensed refrigerant to the load cooler through the decompressor to reduce the low temperature. In the refrigeration apparatus to be obtained, a first refrigerant supply flow path through which the re-low temperature refrigerant flows to the load cooler through the final stage decompressor, and the intermediate heat exchanger without the intermediary of the final stage decompressor Relatively high-temperature refrigerant flows to the load cooler without exchanging heat in intermediate heat exchangers And a second refrigerant supply channel occupying provided,
A refrigeration system in which an opening / closing valve is provided in each of the first refrigerant supply flow path and the second refrigerant supply flow path so that the lowest temperature refrigerant and a relatively high temperature refrigerant can be switched and supplied to the load cooler.