JPS58217162A - Heat pump device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump device having a plurality of compressors with different suction pressure levels, and more particularly to a heat pump device that controls the amount of oil in the plurality of compressors to an appropriate amount.

A heat pump device equipped with multiple compressors is known as a device that can suppress the rise in discharge temperature and increase operating efficiency by reducing the pressure ratio.
In this heat pump system, if the distribution of oil to each compressor is poor, one compressor will have too much oil, causing severe forming phenomenon or oil hammer effect at startup, and another compressor will have too little oil. This has the potential to cause various negative effects such as seizure of sliding parts.

Next, an example of a conventional heat pump device using two compressors will be described with reference to FIG. In the figure, 1 is the first
A compressor, 2 a first condenser, 3 a gas-liquid separator, 4 a first pressure reducer, 5 an evaporator, 6 a second compressor, 7 a second condenser,
Reference numeral 8 denotes a second pressure reducer, and the above-mentioned devices are connected via piping to form a refrigerant circuit as shown in the figure. The gas refrigerant that has become high temperature and high pressure in the first compressor 1 passes through the discharge pipe 9 to the first condenser 2.
Here, the refrigerant is partially condensed and liquefied, and passes through the first condenser outlet pipe 10 to the gas-liquid separator 3 in a saturated gas-liquid two-phase flow state. The saturated gas refrigerant passes through the second compressor suction line 13 and is sucked into the second compressor 6, where it becomes a high-pressure gas refrigerant that is even higher than the gas refrigerant compressed by the first compressor 1. This high-pressure gas refrigerant then flows into the second condenser 7 via the second compressor discharge line 14, where it is completely condensed and liquefied.

After that, it passes through the second condenser outlet pipe 15 and the second pressure reducer 8, and then connects to the liquid reservoir at the lower part of the gas-liquid separator 3 of the main refrigerant circuit.
It is connected to the pipe line 11 between the pressure reducers 4 and merges with the saturated liquid coming out of the gas-liquid separator 3. The combined liquid refrigerant is completely evaporated through the first pressure reducer 4 and the evaporator 5, and reaches the first compressor 1 through the suction line 12 of the first compressor. The refrigerant continuously circulates through the refrigerant circuit described above, and is heated in the first condenser 2 and second condenser 7, heating the air, water, brine, etc. flowing through both condensers 2.7. 8 In the apparatus configured as described above, the first compressor 1 is
The amount of oil in the second compressor 6 tends to increase, and the amount of oil in the second compressor 6 tends to decrease, but since the pressures in the oil reservoirs of the side compressors are different, as in the case of compressors having the same pressure, It is not possible to simply provide a pressure equalizing pipe to keep the oil level in the compressor constant. Therefore, in the refrigerant circuit shown in Fig. 1, each compressor is installed so that the oil levels of the first compressor 1 and the second compressor 6 are at the same height on a horizontal plane, and The lower parts of the reservoirs are connected by a thin oil return pipe 17 with a control valve 16 interposed therebetween. The oil return action is carried out by the second compressor 6.
The control valve 1 is stopped intermittently to make the pressure in the oil sump of the second compressor 6 equal to the pressure in the oil sump of the first compressor 1.
6 was opened to return excess oil accumulated in the first compressor 1 to the second compressor 6 via an oil return pipe 17. Then, when the oil level returns to its original state, control valve 1
The oil amount was controlled by repeating operations such as closing the second compressor 6 and operating the second compressor 6 again.

However, in the oil level control method as described above, it is necessary to stop the second compressor 6 intermittently, which causes problems such as a decrease in operating efficiency.

The present invention was invented in view of the above problems, and an object of the present invention is to provide a heat pump device that appropriately and automatically controls the amount of oil in a plurality of compressors.

In order to achieve the above object, the present invention forms the oil sump of the first compressor in a high-pressure manner, and connects the oil sump of the second compressor with a float valve chamber, and the float valve chamber is provided with a high-pressure oil sump. The lower part of the oil reservoir of the first compressor and the valve part of the float valve chamber are connected via a thin tube, and the valve part opens the circuit in response to a decrease in the oil level in the float valve chamber. It has a feature that the oil in the oil sump of the first compressor flows into the float valve chamber.

An embodiment of the present invention will be explained below based on FIG. 1 is a first compressor, 2 is a first condenser, 3 is a gas-liquid separator, 4 is a first pressure reducer, 5 is an evaporator, 6 is a second compressor, 7 is a second condenser, and 8 is a second compressor. Each of the above-mentioned devices is connected to the two pressure reducers by piping as shown in the figure, forming a refrigerant circuit similar to the conventional example shown in FIG. However, the first compressor 1 is a high-pressure chamber compressor in which the oil reservoir is on the high-pressure side. Further, a float valve chamber 18 is connected to an oil reservoir (not shown) in the second compressor 6 via a pipe 19. This flow valve chamber 18 is equipped with a float valve 18a having a valve portion 18a arranged above, and when the oil level in the float valve chamber 18 communicating with the oil reservoir of the second compressor drops below the set oil level, the float lowers and the valve is opened. Part 18a
The valve portion 18a is formed in such a structure that when the valve 18a opens and the oil level rises, the valve portion 18a closes. The lower part of the oil reservoir (not shown) of the first compressor 1 and the valve part 18a are connected by a thin tube 20.
a is opened, and the oil reservoir part of the first compressor 1 and the float valve chamber 1
8 are formed so as to communicate with each other.

In the heat pump device having the above structure, the suction pressure of the second compressor 6 is lower than the discharge pressure of the first compressor 1 due to pressure loss in the first compressor 2 and the pipes 9, 10, and 13. . Also, since the oil sump of the first compressor 1 is on the discharge side and the oil sump of the second pressure P6 is on the suction side, the pressure of the oil sump of the second compressor P6 is equal to that of the oil sump of the first compressor 1. The pressure will be lower than that of the

Next, the operation of the heat pump device will be explained.

The heat pump device is operated, and during operation, the second
When the oil level in the compressor 6 decreases, the oil level drops, the float 18b of the float valve 18 is lowered, and the upper valve portion 18a is opened. Due to the differential pressure in the oil reservoir of the side compressor 1.6, oil accumulated in the first compressor 1 more than necessary is removed from the thin tube 20 and the valve part 18a.
The oil flows into the float valve chamber 18 through the pipe 19, and then into the oil reservoir of the second compressor 6, so that the oil level in the compressor 6 is maintained appropriately. As the oil returns to the second compressor 6, the oil level in the shift float valve chamber 18 rises, and when the oil level reaches the specified level, the valve part 18a closes, and
Place the inflow of oil into.

As mentioned above, this oil amount control can be performed automatically without stopping the side compressor during operation of the apparatus, and has the advantage of being easy to perform.

In addition, in devices where the second compressor 6 is stopped and only the first compressor 1 is operated, a control valve 16 is provided in the middle of the thin tube 20, and when the second compressor 6 is stopped, the oil It may be formed so as to stop the inflow of.

As explained above, according to the present invention, in a heat pump device using a plurality of compressors, the amount of oil in each compressor can be increased by a device with a simple structure that connects the oil reservoirs of each compressor through a float valve chamber. can be properly and automatically controlled, and since this oil amount control method does not require stopping the compressor, the heat pump device has effects such as being able to operate efficiently.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram of a conventional heat pump device, and FIG. 2 is a configuration diagram of a refrigerant circuit and an oil amount control device of a heat pump device showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... First compressor, 2... First condenser, 3... Gas-liquid separator, 4... First pressure reducer, 5... Evaporator, 6...
...Second compressor, 7...Second condenser, 8...Second pressure reducer, 16...Control valve, 18...Float valve chamber, 1
8a... Valve section, 18b... Float, 19... Piping, 20... Thin tube. Agent Patent Attorney Tadashi Akimoto Figure 1 0 Figure 2

Claims (1)

[Claims] 1. A main refrigerant circuit is formed by sequentially connecting a first compressor, a first condenser, a gas-liquid separator, a first pressure reducer, and an evaporator with piping;
The upper part of the gas-liquid separator is connected to a second compressor via a cold pipe, and the second compressor, a second condenser, and a second pressure reducer are sequentially connected to the liquid outlet of the gas-liquid separator. A float valve chamber is connected to the side passage and connected to the oil sump of the second compressor, and the float valve chamber is provided with a float valve that opens in response to a drop in the oil level, and the first compressor has a high pressure in the oil sump. The lower part of the oil sump of the compressor and the above valve part are connected through a thin tube, and the float valve opens depending on the oil level in the float valve chamber, and the oil sump of the first compressor and the float valve chamber communicate with each other.゛Featured heat pump device. 2. The heat pump device according to claim 1, wherein the float valve chamber has a valve portion formed above the float. 3. The heat pump device according to claim 1, wherein the float valve chamber is attached to the outside of the second compressor. 4. The heat pump device according to claim 1, wherein a control valve is interposed in the thin tube.