JPS6245454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor compression type refrigeration system that utilizes the latent heat of a refrigerant, and is particularly designed to prevent liquid return to the compressor and reduce the startup load.

Fig. 1 is a diagram showing an example of a refrigerant cycle of a conventional refrigeration system. In the figure, 1 is a compressor, 2 is a condenser, 3 is a pressure reducing device, and 4 is an evaporator, which are connected in sequence. This constitutes a refrigeration system.

In such a conventional refrigeration system, refrigerant gas that has become high temperature and high pressure in the compressor 1 is cooled and liquefied in the condenser 2, becomes low temperature and low pressure in the pressure reducing device 3, and is guided to the evaporator 4. When the refrigerant liquid is gasified in the evaporator 4, it absorbs heat from the surroundings and performs freezing. After this, the frozen gas is sucked into the compressor 1.

In such conventional refrigeration equipment, most of the liquid refrigerant in the condenser 2 flows into the evaporator 4 due to the pressure difference between the condenser 2 and the evaporator 4 after the operation is stopped, and a large amount of liquid refrigerant flows into the evaporator 4. Refrigerant concentrates.

If operation is started in this state, the liquid refrigerant accumulated in the evaporator 4 will rapidly flow into the compressor 1, which may cause a malfunction of the compressor 1 or place an excessive load on the electric motor (not shown). . In addition, since the evaporation pressure and condensation pressure follow the course shown by curve a in Fig. 6, from the stopped state c to the steady state d, in Fig. 7 (showing the relationship between operating time and compression work), As shown by curve e, there was a drawback that an excessive ride-through load was generated in the middle.

Note that Y in FIG. 6 indicates the direction in which the compression work increases, and X ₁ to _{X o} indicate equal compression work lines.

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and by guiding the liquid refrigerant in the condenser into the bypass liquid storage container when the refrigeration equipment is stopped, a large amount of refrigerant is delivered to the compressor at the start of operation. It is an object of the present invention to provide a refrigeration system that can reduce the overload load by preventing liquid refrigerant from flowing in and keeping the inside of the refrigeration system in a refrigerant-sufficient state at the start of operation.

Embodiments of the refrigeration system of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the configuration of one embodiment. In FIG. 2, the same parts as in FIG. 1 are given the same reference numerals and their explanations will be omitted.

As is clear from comparing FIG. 2 with FIG. 1, the compressor 1, condenser 2, pressure reducing device 3, and evaporator 4 in FIG. 2 are the same as in FIG.
The parts described below are different from FIG. 1.
That is, a refrigerant circuit including a solenoid valve 5 ₁ , a liquid reservoir 6 , a solenoid valve 5 ₂ , and a pressure reducing device 8 is provided in parallel with the pressure reducing device 3 .

The electromagnetic valve ₅₁ is provided in the bypass pipe ₇₁ , and is closed during operation and opened when stopped.
Further, the solenoid valve ₅₂ is attached to the bypass pipe ₇₂ , and is a solenoid valve that opens during operation and closes when stopped.

The liquid reservoir 6 is constructed as shown in FIG. 3, and the bypass pipes 7 ₁ and 7 ₂ are connected to both ends thereof. Note that 10 in FIG. 6 indicates a refrigerant liquid.

Next, the operation of the refrigerant device of the present invention configured as above will be explained. During normal operation,
Since the solenoid valve ₅₁ is closed and the solenoid valve ₅₂ is open, the refrigerant liquid 10 does not accumulate in the liquid reservoir 6, and the operating state is exactly the same as the conventional refrigeration system shown in FIG. becomes.

On the other hand, when the refrigeration equipment is stopped, the solenoid valve 5 ₁
is open and the solenoid valve ₅₂ is closed, so the condenser 2 flows into the liquid reservoir 6, which has been made equal to the evaporation pressure.
of liquid refrigerant flows through the solenoid valve ₅₁ , and the amount of liquid refrigerant in the refrigeration system decreases.

Therefore, it is possible to prevent a large amount of refrigerant liquid from concentrating on the evaporator at the time of restarting the operation. In other words, after the start of operation, a large amount of liquid refrigerant suddenly flows into the compressor 1.
I won't be able to return to it.

Furthermore, since the solenoid valve 5 ₁ is closed and the solenoid valve 5 ₂ is opened at the start of operation, the liquid refrigerant in the liquid reservoir 6 gradually flows into the refrigeration system through the bypass pipe 7 ₂ and the solenoid valve 5 ₂ . return.

As a result, for a while after the start of operation, the refrigeration system operates with an insufficient amount of refrigeration, and the evaporation pressure, condensation pressure, and condensation pressure follow the course of curve b shown by the broken line in Figure 6, and from the stop state c. A steady state d is reached. At this time, since the compression work progresses as shown by the broken line curve f in FIG. 7, generation of an excessive ride-through load can be prevented.

Note that if only the bypass pipe 7 ₂ and the solenoid valve 5 ₂ are used, the refrigerant liquid in the liquid reservoir 6 will suddenly return to the inside of the refrigeration apparatus, and the above operation may not be realized. In this case, as shown in FIG. 2, a pressure reducing device 8 may be provided to adjust the flow rate.

If the arrangement is such that the refrigerant liquid in the condenser 2 is difficult to flow into the liquid storage container 6 when the operation is stopped, by providing a bypass pipe 7 ₃ and a pressure reducing device 9 as shown in FIG. By guiding the refrigerant gas in the liquid reservoir 6 as shown in FIG.

Furthermore, in the above embodiment, the opening of the solenoid valve ₅₁ and the closing of the solenoid valve ₅₂ were carried out when the operation was stopped. It is also possible to adjust the amount of liquid refrigerant stored in the storage container 6.

As described above, according to the refrigeration device of the present invention,
By connecting a bypass pipe to the inlet and outlet of the pressure reducing device, connecting a liquid reservoir between the two bypass pipes, and providing a solenoid valve at the inlet and outlet of the liquid reservoir, liquid refrigerant can be prevented from flowing when stopped. Since the refrigerant is stored in the liquid storage container, a large amount of refrigerant liquid does not return to the compressor at the start of operation, which prevents excessive load from being placed on the electric motor, improving reliability. . Further, by reducing the ride-through load, a compact and inexpensive compressor can be obtained.

[Brief explanation of the drawing]

Figure 1 is a refrigerant cycle diagram of a conventional refrigeration system.
Fig. 2 is a refrigerant cycle diagram of an embodiment of the refrigeration system of the present invention, Fig. 3 is a diagram showing the configuration of a liquid reservoir in the refrigeration system of Fig. 2, and Fig. 4 is a diagram showing another embodiment of the refrigeration system of the invention. Fig. 5 is a diagram showing the structure of the liquid reservoir in the refrigeration system shown in Fig. 4, and Fig. 6 is a characteristic diagram showing the progression of condensing pressure and evaporation pressure in the conventional refrigeration system and the present invention. , FIG. 7 is a characteristic diagram showing the compression work of the conventional refrigeration system and the present invention. 1... Compressor, 2... Condenser, 3, 8, 9...
Pressure reducing device, 4...Evaporator, _51,52 ...Solenoid valve, ₆ ...Liquid reservoir, _71-73 ...Bypass pipe, 10... _Refrigerant liquid. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A compressor that compresses refrigerant and discharges it at high temperature and high pressure, a condenser that condenses and cools the high temperature and high pressure refrigerant discharged from this compressor, and liquefies the refrigerant in this condenser. In a refrigeration system consisting of a pressure reducing device that reduces the pressure of a refrigerant liquid to a low temperature and low pressure, and an evaporator that evaporates and gasifies the low temperature, low pressure refrigerant liquid that has been reduced in pressure by this pressure reducing device and returns it to the compressor, a liquid storage container is used. first and second bypass pipes provided and connected to the inlet and outlet of the container and the pressure reducing device, respectively;
a first electromagnetic valve provided in the bypass pipe that closes during operation and opens when operation is stopped; a first electromagnetic valve provided in the second bypass pipe that opens during operation and closes when stopped; together with the first electromagnetic valve, the refrigerant is discharged when stopped; A refrigeration system characterized by having a second electromagnetic valve that stores refrigerant in a liquid storage container and prevents refrigerant from storing in the liquid storage container during operation. 2. The refrigeration system according to claim 1, wherein the second bypass pipe is provided with a second pressure reducing device. 3. Refrigeration according to claim 1, characterized in that a third bypass pipe having a third pressure reducing device is provided between the upper part of the liquid storage container and the evaporator side of the second bypass pipe. Device.