JPH02242051A - Refrigerator - Google Patents

Abstract

PURPOSE:To start promptly a refrigerating device for cold temperature service where mixed refrigerant is used, and reduce swiftly the temperature continuously until a specified temperature is obtained from the beginning of operation by installing a bypass pipe which communicates with a low pressure section immediately before a vaporizer from a high pressure section immediately before other decompression devices excluding the decompression device in the final stage by way of an ON/OFF valve, and a decompression mechanism. CONSTITUTION:When an attempt is made to open an ON/OFF valve 12 at the same time when operation starts, a part of R13 liquefied in a first vapor- liquid separator 3 flows into a vaporizer 9 by way of a decompression device 13 of a bypass pipe 14. As a result, low temperature liquefied refrigerant flows into the vaporizer, which makes it possible to generate a cooling capacity. Furthermore, the refrigerant which has left the vaporizer 9 is absorbed into a compressor 1 passing through a second intermediate heat exchanger 7 and a first intermediate heat exchanger 4. It is, therefore, possible to cool the heat exchangers swiftly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a refrigeration system, and more particularly to a refrigeration system suitable for shortening the start-up time in a refrigeration cycle that obtains a low temperature.

[Conventional technology]

Conventionally, low-temperature refrigeration equipment uses a mixed refrigerant made by mixing a plurality of refrigerants with different boiling points.

For example, the technique described in Japanese Utility Model Application Publication No. 62-189563 or Japanese Utility Model Application Publication No. 62-189564 is known.

That is, the refrigeration equipment described in each of these publications compresses a mixed refrigerant, cools it in a condenser, and separates the partially condensed gas-liquid mixed refrigerant into gas refrigerant and liquid refrigerant in an initial stage gas-liquid separator.
This gas refrigerant is led to the next stage gas-liquid separator through one flow path of the first stage cascade condenser, and the liquid refrigerant passes through the first stage glue layer means to the first stage together with the gas refrigerant from the other flow path of the next stage cascade condenser. The liquid refrigerant is returned to the compressor through the other flow path of the cascade condenser, and then connected to the next stage gas-liquid separator and cascade condenser in the same way, and the liquid refrigerant from the final stage cascade condenser is evaporated via the expansion means. The gas refrigerant from the evaporator is led to the other flow path of the final stage cascade condenser.

In particular, in the refrigeration system described in Japanese Utility Model Application Publication No. 62-189563, in which the liquid refrigerant outlet of the final stage gas-liquid separator is connected to the final stage expansion means through one flow path of the switching valve. At the same time, it is connected to the inlet of the expansion means connected to the evaporator through the other flow path of this switching valve.

[Problem to be solved by the invention]

Similar to the present invention, the above-mentioned conventional technology aims to shorten the start-up time of the refrigeration equipment, but it does not take into consideration the effect of shortening the start-up time under a wide range of conditions, so that sufficient effects cannot be obtained. 1IJ-There was a title.

The present invention was made in order to solve the problems in the prior art described above, and it quickly starts up a low-temperature cooling device using a mixed refrigerant, and continuously operates from the start of operation until a desired low temperature is obtained. The object of the present invention is to provide a cooling device that enables rapid temperature reduction.

[Means to solve the problem]

In order to achieve the above object, a first aspect of the refrigeration system according to the present invention includes a single compressor that compresses a mixed refrigerant made by mixing a plurality of refrigerants, and a condenser that cools the compressed air. a first-stage gas-liquid separator that separates the refrigerant from the condenser into gas refrigerant and liquid refrigerant, and a low-pressure, low-temperature refrigerant that guides the separated gas refrigerant into one flow path and flows through the other flow path. The basic configuration includes a first-stage intermediate heat exchanger for cooling, a first-stage pressure reduction mechanism for reducing the pressure of the separated liquid disparate, and a piping system that guides the reduced pressure low-pressure low-temperature refrigerant to the first-stage intermediate heat exchanger, Connected to an intermediate heat exchanger (hereinafter, it is equipped with at least one stage of the next stage gas-liquid separator, intermediate heat exchanger, pressure reduction mechanism, and piping system with the same configuration, and connected to the final stage intermediate heat exchanger and pressure reduction mechanism) In a refrigeration system equipped with an evaporator that generates a gas refrigerant, and a piping system that returns to the compressor via this evaporator and each intermediate heat exchanger, other pressure reduction mechanisms other than the final stage pressure reduction mechanism are used. A bypass pipe is provided that communicates from a high pressure section immediately before the mechanism to a low pressure section immediately before the evaporator via an on-off valve and a pressure reducing mechanism.

In addition, in order to achieve the above object, the configuration of the second invention related to the refrigeration apparatus of the present invention is based on the same premise, at least the on-off valve is A bypass pipe is provided which communicates with the pressure reduction mechanism at the final stage via the pressure reducing mechanism.

Furthermore, the configuration of the third invention related to the refrigeration apparatus of the present invention is as follows:
On the same premise, a bypass pipe is provided that communicates from the low pressure section immediately after the pressure reducing mechanism other than the final stage pressure reducing mechanism to the low pressure section immediately before the evaporator via at least an on-off valve.

Furthermore, in any of the above configurations, a sensor for detecting the temperature of the evaporator and a controller for controlling at least one on-off valve of the bypass pipe are provided, and the at least one on-off valve is controlled according to the temperature of the evaporator. It is something to control.

Additionally, in order to achieve the above purpose.

In the present invention, at startup, a flow path is formed that bypasses a plurality of intermediate heat exchangers, and the refrigerant discharged from the compressor is circulated in the order of the condenser, the pressure reduction mechanism, and the evaporator, and the evaporator is rapidly activated. First, the temperature of other components is lowered.

Furthermore, the temperature of the evaporator is detected and the on-off valves of multiple bypass pipes are sequentially switched according to commands from the controller.
This allows the temperature of the evaporator to be rapidly lowered while bypassing the intermediate heat exchanger.

[Effect]

The temperature of each part of a refrigeration system using a mixed refrigerant is the same as the ambient temperature immediately before startup.

Therefore, the low boiling point refrigerant sealed in the refrigeration device is gasified. When the compressor is started in this state, the refrigerant, including the gasified low-boiling refrigerant, is forced to flow through a complex flow path consisting of multiple intermediate heat exchangers, refrigerant separators, and pressure reduction mechanisms, resulting in a large A pressure loss occurs and, as a result, the low-pressure pressure of the refrigerant system decreases. As a result, the refrigerant circulation flow rate is drastically reduced, cooling performance is lowered, and the temperature of the evaporator decreases even more slowly.

In this case, the present invention can form a bypass pipe that directly flows from the condenser to the evaporator via the low-pressure mechanism, so the refrigerant flow path becomes simple, the refrigerant flows easily, and the cooling performance increases. Become.

The temperature of the evaporator can be reduced rapidly.

At this time, if the inlet of the bypass piping is located at a location that contains a large amount of high boiling point refrigerant, there is a limit to the temperature drop of the evaporator, so evaporation (
The inlet of the bypass piping is sequentially switched to the downstream side while detecting the temperature of (to).

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

First, FIG. 1 is a refrigeration cycle system M diagram of a refrigeration apparatus according to a first embodiment of the present invention.

1st ai! 1, l is a compressor, 2 is a condenser, 3 is a first gas-liquid separator related to the first stage gas-liquid separator, 4 is the first stage, that is, the first intermediate heat exchanger, and 5 is the first stage, that is, the first intermediate heat exchanger. a first pressure reducing mechanism; 6 is a second pressure reducing mechanism related to the first stage gas-liquid separation III device;
7 is a first stage or second intermediate heat exchanger; 8 is a next stage or second pressure reduction mechanism; 9 is an evaporator;
0 is the final stage pressure reducing mechanism, here the third pressure reducing mechanism,
11 is an expansion tank, 12 is an on-off valve provided in the bypass pipe 14, 13 is a pressure reduction mechanism provided in the middle of the bypass pipe 14, and 14 is an evaporator from a high pressure section immediately before the first pressure reduction mechanism 5. This is a bypass piping that communicates with the low pressure section just before 9.

In such a refrigeration cycle configuration, a capillary tube or a manual or electric expansion valve may be used as the pressure reduction mechanism. In Figure 1.

It is assumed that a capillary tube is used.

As the refrigerant sealed in this refrigeration cycle, for example, R12, R13, and R14 are mixed and used in descending order of boiling point.

First, the operation in the case of steady operation will be explained.

The refrigerant discharged from the compressor 1 is cooled in the condenser 2,
R12, which has the highest boiling point, is condensed and liquefied, and is separated into a gaseous refrigerant and a liquid refrigerant in the first gas-liquid separator 3. The liquid refrigerant is throttled by the first pressure reducing mechanism 5, becomes a low-pressure low-temperature refrigerant, and flows into the low-pressure side inlet of the first intermediate heat exchanger 4. The gaseous refrigerant is mainly composed of R13 and R14, and is cooled in the first intermediate heat exchanger 4 by exchanging heat with the low-temperature, low-pressure refrigerant flowing through the other passage, and at the 24th point, R13, which has a higher boiling point, is liquefied. Then, the second gas-liquid separator 6 separates the R14 gas refrigerant and the R13 liquid refrigerant. The liquid separation medium is throttled by the second pressure reducing mechanism 8 and becomes a low pressure, low humidity refrigerant that flows into the low pressure side inlet of the second intermediate exchanger 7. The R14 gaseous refrigerant is the second intermediate heat exchanger! ! It is cooled and liquefied in I7, and the pressure is reduced by the final stage pressure reducing mechanism 10, and it flows into the evaporator 9, generating the lowest temperature in this refrigeration cycle. The refrigerant leaving the evaporator is transferred to the second. It passes through the first intermediate heat exchangers 7 and 4 and is sucked into the compressor 1.

Next, a situation in which such a refrigeration system is activated will be described.

Before startup, each part of the refrigeration system is at the same temperature as the ambient temperature, and in the case of this embodiment, among the mixed refrigerants used, only R12 has a liquid state. The other R13 and R14 have low boiling points and therefore exist as gaseous refrigerants in equipment including the expansion tank 11.

First, consider the case where startup is performed without using the bypass circuit 14.

When compressor 1 starts operating, condenser 2 further increases R1.
Liquefaction of 2 is promoted. R12 is separated as a liquid refrigerant in the first gas-liquid separator 3, the pressure is reduced in the first pressure reducing mechanism 5, and it flows into the low pressure side of the first intermediate heat exchanger 4 to cool the intermediate heat exchanger. do. R separated in the first gas-liquid fraction 11113
The gas refrigerants 13 and R14 are cooled in the first intermediate heat exchanger 4, but are only cooled by R12, which has become low temperature and low pressure. This occurs due to insufficient cooling because there is no refrigerant with a lower temperature flowing in from the low pressure side of the vessel 7. As a result, in the first intermediate heat exchange l1I4, the amount of R13 condensed and liquefied is small;
In the second gas-liquid separator 6, the uncondensed R13 gaseous refrigerant flows into the high-pressure side of the second intermediate heat exchanger 7, mixed with the R14 gas.

The small amount of R13 liquefied refrigerant that exited the second gas-liquid separator 6 is
The gaseous refrigerant is depressurized by the second pressure reducing mechanism 8 and flows into the low pressure side of the second intermediate heat exchanger 7, but since there is little liquefaction flow, the gaseous refrigerant is hardly liquefied in the second intermediate heat exchanger 7. is about to flow through the final stage pressure reducing mechanism 10. However, since it is a gaseous refrigerant, in a pressure reducing mechanism with a fixed resistance such as a capillary tube, there will be a large flow path resistance, and the pressure reducing mechanism 10 will be in a situation where the refrigerant cannot flow most of the time. As a result, the low pressure of the refrigeration system decreases without decreasing the temperature of the evaporator 9, and the flow rate of refrigerant discharged from the compressor 1 also decreases extremely, making it increasingly difficult for the temperature of the evaporator 9 to decrease. . That is, after the start of operation, the state in which the cooling capacity of the evaporator 9 is not generated continues for a long period of time.

Therefore, a case where the by-pipe piping 14 is used will be explained.

When the on-off valve 12 is opened at the same time as the start of operation, a part of the R13 liquefied in the first gas-liquid separator 3 flows into the evaporator 9 via the pressure reduction mechanism 13 of the bypass piping 14. Simultaneously with the start of M, the liquefied refrigerant at a low temperature flows in the evaporator 9, so that cooling capacity can be generated.

Furthermore, the refrigerant that has exited the evaporator 9 passes through the second intermediate heat exchanger 7 and the first intermediate heat exchanger 4 and is sucked into the compressor 1, thereby rapidly cooling these heat exchangers. be able to. The first pressure reducing device 5 does not pass through the bypass pipe 14.
The flow of the refrigerant circulating through the gaseous refrigerant and the gaseous refrigerant separated by the first gas-liquid separator 3 is as described above.

According to this embodiment, the temperatures of the intermediate heat exchanger and evaporator of the refrigeration system can be lowered to a low level, so a continuous rapid drop-down effect can be expected from the start of operation until the desired low temperature is obtained. Therefore, it has the effect of saving power and improving reliability.

Next, FIG. 2 is a refrigeration cycle system diagram of a refrigeration system according to a second embodiment of the present invention. In FIG. do.

The difference between the embodiment shown in FIG. 2 and the embodiment shown in FIG. 1 is as follows.
The bypass pipe 14A is not provided with a pressure reducing mechanism, and the on-off valve 1 is
2, and the bypass pipe 14A extends from the high pressure section immediately before the first pressure reducing mechanism 5 to the third pressure reducing mechanism 10 related to the final stage.
It is connected so that it communicates with the front of the

According to the embodiment shown in FIG. 2, the same effects as the previous embodiment shown in FIG. 1 can be expected.

Next, FIG. 3 shows a refrigeration cycle system diagram of a refrigeration system according to a third embodiment of the present invention. In FIG. 0, parts with the same symbols as in FIG. do.

The difference between the embodiment shown in FIG. 3 and the second embodiment is that the bypass pipe 14B extends from the low pressure section immediately after the first pressure reducing mechanism 5 to immediately after the third pressure reducing machine 41110 related to the final stage. That is, it is connected so as to communicate with the low pressure section immediately before the evaporator 9.

According to the embodiment shown in FIG. 3, the same effects as the embodiments shown in FIGS. 1 and 2 can be expected.

Next, FIG. 4 is a refrigeration cycle system diagram of a refrigeration system according to a fourth embodiment of the present invention. In FIG. 6, parts with the same reference numerals as those in FIG. do.

In addition to the configuration of the embodiment shown in FIG. 1, the configuration of the embodiment shown in FIG.
and a controller 15 that takes in the output signals of these temperature sensors 16 and 17 and controls the on-off valve 12.

The on-off valve 12 is opened at the same time as the start of operation.

When the effect of the bypass piping 14 is fully realized and the temperature of the intermediate heat exchanger including the evaporator 9 decreases to a certain degree, a situation arises in which the use of the bypass piping 14 is not desirable.

In other words, even if the evaporator 9 is able to generate a low temperature, the bypass pipe 14 will still have high boiling point R flowing from the upstream section.
12 flows into the evaporator 9 and prevents the evaporator 9 from decreasing by 21 degrees. Temperature sensors 16 and 17 provided on the evaporator
detects this state, and the controller 15 performs an operation to close the IA closing valve 12 while determining this state.

As a result, smooth operation is possible from the time the device starts operating until the desired desired low temperature is obtained.

Note that either one of the temperature sensors 16 and 17 may be used, or two temperature sensors may be used to detect a temperature difference.

Next, FIG. 5 is a refrigeration cycle system diagram of a refrigeration system according to a fifth embodiment of the present invention.
Components with the same reference numerals as those in the drawings are the same parts as in the previous embodiment, so their explanation will be omitted.

The configuration of the embodiment shown in FIG. 5 includes a first bypass pipe 14 having an on-off valve 12 and a pressure reducing mechanism 13, which extends from a high pressure section immediately before the first pressure reducing mechanism 5 to a low pressure section immediately before the evaporator 9. from the pressure section immediately before the pressure reducing mechanism 8 of No. 2 to the low pressure section immediately before the evaporator 9,
It is equipped with an on-off valve 12' and a second bypass pipe 14' having a pressure reducing mechanism 13'.

In the embodiment shown in FIG. 5, the temperature of the evaporator 9 is measured by a temperature sensor 16.
While detecting the temperature of the evaporator 9 from the start of operation, (1) Open the on-off valve 12 and close the on-off valve 12'.

(2) Control is performed to close the on-off valve 12 and open the on-off valve 12', and (3) to close both the on-off valves 12 and 12'.

According to the embodiment shown in FIG. 5, more fine-grained operation control is possible than in the fourth embodiment.

In each of the above embodiments, gas-liquid separation is performed in two stages, but the present invention is not limited to this, and the present invention can be applied even when the number of stages is further increased.

〔Effect of the invention〕

As explained in detail above, according to the present invention, a low-temperature refrigeration system using a mixed refrigerant can be started quickly, and the temperature can be rapidly lowered continuously from the start of operation until the desired low temperature is obtained. It is possible to provide a refrigeration device that does the following.

[Brief explanation of drawings]

1 is a refrigeration cycle system M diagram of a refrigeration system according to a first embodiment of the present invention, FIG. 2 is a refrigeration cycle system diagram of a refrigeration system according to a second embodiment of the present invention, and FIG. is a refrigeration cycle system diagram of a refrigeration system according to a third embodiment of the present invention, FIG. 4 is a refrigeration cycle system diagram of a refrigeration system according to a fourth embodiment of the present invention, and FIG. It is a refrigeration cycle system diagram of the refrigeration apparatus based on the 5th Example. DESCRIPTION OF SYMBOLS 1... Compressor, 2... Condenser, 3... ↓th gas-liquid separator, 4... First intermediate heat exchanger, 5... First pressure reduction mechanism, 6... ...Second gas-liquid separator, 7...Second intermediate heat exchanger, 8...Second pressure reduction mechanism, 9...Evaporator, 10...Third pressure reduction mechanism, 12 .12'...
Opening/closing valve, 13.13'...pressure reduction mechanism, 14.14'
14A, 14B... Bypass piping, 15... Controller, 16.17... Temperature sensor. '411!1 Hair 3 Z No. 2 Mouth 4 eyes

Claims (1)

[Claims] 1. A single compressor that compresses a mixed refrigerant made by mixing a plurality of refrigerants, a condenser that cools the compressed air, and a refrigerant from the condenser that is a gas refrigerant and a liquid refrigerant. an initial stage intermediate heat exchanger that guides the separated gas refrigerant into one flow path and cools it with a low-pressure low-temperature refrigerant flowing through the other flow path; The basic structure consists of a first-stage pressure reducing mechanism that reduces the pressure of the refrigerant, and a piping system that leads the reduced pressure, low-pressure, low-temperature refrigerant to the first-stage intermediate heat exchanger, and is connected to the intermediate heat exchanger (hereinafter, the next-stage gas refrigerant with the same configuration). an evaporator that is equipped with at least one stage of a liquid separator, an intermediate heat exchanger, a pressure reduction mechanism, and a piping system, and that is connected to the final stage intermediate heat exchanger and pressure reduction mechanism to generate a gas refrigerant; and this evaporator and each intermediate stage. In a refrigeration system equipped with a piping system that returns to the compressor via a heat exchanger, the high-pressure part immediately before the pressure reducing mechanism other than the final stage pressure reducing mechanism is passed through the on-off valve and the pressure reducing mechanism. A refrigeration system characterized by having a bypass pipe communicating with a low-pressure section immediately before an evaporator. 2. A single compressor that compresses a mixed refrigerant made by mixing multiple refrigerants, and a single compressor that cools the compressed air. a condenser, an initial stage gas-liquid separator that separates the refrigerant from the condenser into gas refrigerant and liquid refrigerant, and a low-pressure, low-temperature refrigerant that guides the separated gas refrigerant into one flow path and flows through the other flow path. The basic configuration includes a first-stage intermediate heat exchanger that cools the separated liquid refrigerant, a first-stage pressure reducing mechanism that reduces the pressure of the separated liquid refrigerant, and a piping system that guides the reduced pressure low-pressure low-temperature refrigerant to the first-stage intermediate heat exchanger, Connected to an intermediate heat exchanger (equipped with at least one stage of the next stage gas-liquid separator, intermediate heat exchanger, pressure reduction mechanism, and piping system with the same configuration, and connected to the final stage intermediate heat exchanger and pressure reduction mechanism) In a refrigeration system equipped with an evaporator that generates a gas refrigerant and a piping system that returns to the compressor via the evaporator and each intermediate heat exchanger, the pressure reduction mechanism other than the final stage pressure reduction mechanism is A refrigeration system characterized in that a bypass pipe is provided that communicates from the immediately preceding high-pressure section through at least an on-off valve immediately before the final stage pressure reducing mechanism. 3. Compressing a mixed refrigerant formed by mixing a plurality of refrigerants. a single compressor that cools the compressed air; a first stage gas-liquid separator that separates the refrigerant from the condenser into gas refrigerant and liquid refrigerant; A first-stage intermediate heat exchanger cools the low-pressure low-temperature refrigerant that is guided into the flow path and flows through the other flow path; a first-stage pressure reduction mechanism that reduces the pressure of the separated liquid fraction; The basic configuration is a piping system leading to the intermediate heat exchanger, and connected to the intermediate heat exchanger (hereinafter, the system is equipped with at least one stage of the next stage gas-liquid separator, intermediate heat exchanger, pressure reduction mechanism, and piping system with the same configuration). , a refrigeration system comprising an intermediate heat exchanger at the final stage, an evaporator connected to a pressure reduction mechanism to generate a gas refrigerant, and a piping system returning to the compressor via the evaporator and each intermediate heat exchanger. A refrigeration system, characterized in that a bypass pipe is provided which communicates from a low pressure section immediately after a pressure reducing mechanism other than the final stage pressure reducing mechanism to a low pressure section immediately before the evaporator via at least an on-off valve. 4. In any one of claims 1 to 3, a sensor for detecting the temperature of the evaporator and a controller for controlling at least one on-off valve of the bypass pipe are provided, and the at least one on-off valve is controlled according to the temperature of the evaporator. A refrigeration device characterized by controlling an on-off valve.