JPH0541319Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a refrigeration system having a plurality of compressors and an oil return mechanism consisting of an oil separator, an oil tank, and an oil level regulator.

(b) Prior Art Conventionally, this type of refrigeration apparatus has been described in Japanese Utility Model Publication No. 39-26031, etc., and has been constructed as shown in FIG. 30 is a plurality of compressors 3 connected in parallel
1, 32, 33, an oil separator 34, a condenser 35, a liquid receiver 36, an expansion valve 37, an evaporator 38, and an accumulator 39 are sequentially connected through piping. 40, 41, 42 are oil level regulators attached to the respective compressors 31, 32, 33. Reference numerals 43 and 44 designate oil return pipes that connect the respective regulators 40, 41, 42 and the oil separator 34, and have an oil tank 45 in the middle. 46 is a low pressure side pipe 47 between the accumulator 39 and the evaporator 38
This is a communication pipe that connects the oil tank 45 and the oil tank 45. In the refrigeration system having such a configuration, the compressor 31,
The oil contained in the refrigerant gas discharged from the refrigerant gases 32 and 33 via the high-pressure pipe 48 is separated by the oil separator 34 and then supplied to the oil tank 45 based on the pressure difference. This is because the oil tank 45 is communicated with the low pressure side piping 47 through the communication pipe 46, and the inside of the oil tank is maintained at a low pressure. And oil tank 45
The accumulated oil is returned to each compressor 31, 32, 33 via an oil return pipe 44 and oil level regulators 40, 41, 42.

(c) Problems to be solved by the invention However, according to the above configuration, since the oil tank 45 and the low pressure side pipe 47 are always in communication with each other through the communication pipe 46, even if the operation of the refrigeration system is stopped for a long time, Then, the pressure inside the oil tank 45 becomes the same as the pressure on the low pressure side, and the refrigerant remaining in the low pressure side piping 47 flows into the oil tank 45 and becomes trapped.
There is a problem that forming occurs when restarting operation, making the oil supply to each compressor unstable. Furthermore, when refilling or replacing oil in the oil tank 45, the service valve 4 of the oil tank
9 and 50 to close the oil return pipe sides 51 and 52 and open the atmosphere communication side 53 and the oil inlet/output side 54 to bring the inside of the tank 45 to atmospheric pressure, the communication pipe 46 cannot be disconnected from the low pressure side pipe 47. Since the refrigerant flows into the oil tank 45 one after another through the oil tank 45, the pressure inside the tank does not easily become equal to atmospheric pressure. However, there was a problem in that it took time to replenish and replace the oil.

This proposal was developed in consideration of these points, and it prevents the refrigerant from forming due to stagnation in the oil tank, stabilizes the return of oil to each compressor, and makes it easy to replenish and replace oil in the oil tank in a short time. The purpose is to make it possible.

(d) Measures to solve the problem This proposal forms a refrigeration cycle by sequentially connecting multiple compressors, oil separators, condensers, pressure reducing devices, and evaporators in parallel, and
An oil level regulator is provided in each of the compressors, and the regulator and the oil separator are connected by an oil return pipe having an oil tank in the middle, and further, a low pressure side pipe between the compressor and the evaporator, In a refrigeration system that is connected to an oil tank by a communication pipe, the communication pipe is provided with a check valve that prevents the flow of refrigerant from the low-pressure side piping to the oil tank.

(e) Effect The refrigeration system of the present invention has the above-mentioned configuration, so that even if the pressure in the oil tank becomes the same as the pressure on the low pressure side when the operation of the refrigeration system is stopped for a long time, no residual oil remains in the low pressure side piping. This prevents the refrigerant from flowing into the oil tank through the communication pipe, prevents the refrigerant from stagnation in the tank and from forming during restart, and ensures stable oil return to each compressor. On the other hand, when refilling or replacing the oil in the oil tank, the refrigerant in the low pressure side piping will not flow into the oil tank through the communication pipe, so adjust the oil tank service valve. By simply doing this, the inside of the tank can be brought to atmospheric pressure in a short time, making it easy to replenish or replace oil.

(f) Examples Examples of the present invention will be described below based on the drawings.

1 is a plurality of compressors 2, 3, which are connected in parallel.
4, oil separator 5, condenser 6, liquid receiver 7,
This is a refrigeration cycle formed by sequentially connecting an expansion valve 8, an evaporator 9, and an accumulator 10 with piping.
Reference numerals 11, 12, and 13 designate oil level regulators mounted on each compressor so as to communicate with the crank chambers of the respective compressors 2, 3, and 4. 14,1
Reference numeral 5 denotes an oil return pipe which connects each regulator 11, 12, 13 and the oil separator 5 and has an oil tank 16 in the middle. 17 is
This is a communication pipe that connects the low pressure side pipe 18 between the evaporator 9 and the accumulator 10 and the oil tank 16. Reference numeral 19 denotes a check valve provided in the communication pipe 17, and this check valve prevents the flow of refrigerant from the low-pressure side pipe 18 to the oil tank 16.

In the refrigeration system configured in this way, the oil contained in the refrigerant gas discharged from the compressors 2, 3, and 4 via the high-pressure side piping 20 is separated by the oil separator 5, and then the oil is separated by the pressure difference. It is supplied to tank 16. This is oil tank 1
This is because the oil tank is maintained at a lower pressure than the oil separator 5 because the oil tank 6 is connected to the low pressure side pipe 18 through the communication pipe 17. and,
The oil accumulated in the oil tank 16 is transferred to oil return pipes 14, 15 and oil level regulators 11, 1.
It is returned to each compressor 2, 3, 4 via 2, 13. In such a configuration, the communication pipe 17 is provided with a check valve 19 that prevents the flow of refrigerant from the low-pressure side pipe 18 to the oil tank 16. In case,
Even if the pressure inside the oil tank 16 becomes the same as the pressure on the low pressure side, the refrigerant remaining in the low pressure side pipe 18 will not flow into the oil tank 16 via the communication pipe 17, and the refrigerant will not flow into the oil tank 16 through the communication pipe 17. This prevents refrigerant from stagnation and forming during restart, and
6 to each compressor 2, 3, and 4 can be stably supplied. In addition, by providing the check valve 19 in the communication pipe 17 as described above, the oil tank 16 is connected from the low pressure side pipe 18 through the communication pipe 17.
When replenishing or replacing the oil in the oil tank 16, the service valves 21 and 22 are adjusted to close the oil return pipes 23 and 24, and the atmosphere communication side 25 is blocked. By simply opening the oil inlet/output side 26, the inside of the tank can be brought to atmospheric pressure in a short time, and serviceability such as oil replenishment and oil replacement is also improved.

(g) Effects of the invention As described above, this invention consists of multiple compressors connected in parallel, an oil separator, a condenser, a pressure reducing device,
and an evaporator are sequentially connected via piping to form a refrigeration cycle, and each of the compressors is provided with an oil level regulator, and this regulator and the oil separator are connected by an oil return pipe having an oil tank in the middle. Furthermore, in a refrigeration system in which a low-pressure side pipe between a compressor and an evaporator is connected to an oil tank by a communicating pipe, a flow of refrigerant from the low-pressure side pipe to the oil tank is blocked in the communicating pipe. Since the refrigerant is equipped with a check valve that prevents the refrigerant from flowing into the oil tank through the communication pipe, even if the refrigeration equipment is stopped for a long time, the refrigerant remaining in the low-pressure side piping will not flow into the oil tank through the communication pipe. It is possible to stably return oil to each compressor by preventing refrigerant from stagnation within the compressor and from forming during restart. Also, when replenishing or replacing oil in the oil tank, the refrigerant does not flow into the oil tank from the low-pressure side pipe through the communication pipe, so the tank can be brought to atmospheric pressure in a short time. and improve serviceability.

[Brief explanation of the drawing]

Figure 1 is a refrigerant circuit diagram showing an embodiment of the present invention;
The figure is a refrigerant circuit diagram showing a conventional example. 1... Refrigeration cycle, 2, 3, 4... Compressor,
5... Oil separator, 6... Condenser, 8...
Expansion valve, 9... Evaporator, 11, 12, 13... Oil level regulator, 14, 15... Oil return pipe, 16... Oil tank, 17... Communication pipe, 1
8...Low pressure side piping, 19...Check valve.

Claims (1)

[Scope of utility model registration request] A refrigeration cycle is formed by sequentially connecting a plurality of compressors, an oil separator, a condenser, a pressure reducing device, and an evaporator connected in parallel, and an oil level regulator is provided for each of the compressors. In a refrigeration system in which a regulator and the oil separator are connected by an oil return pipe having an oil tank in the middle, and a low pressure side pipe between a compressor and an evaporator is further connected to the oil tank by a communication pipe. . A refrigeration system, characterized in that the communication pipe is provided with a check valve that prevents the flow of refrigerant from the low-pressure side pipe to the oil tank.