JP3197768B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus (hereinafter referred to as "air conditioner"), and more particularly to an air conditioner having an oil balance pipe for balancing an oil amount among a plurality of compressors. Related to the structure.

[0002]

2. Description of the Related Art Generally, in an air conditioner in which a plurality of compressors are connected in parallel, an oil separator for separating oil contained in a refrigerant is provided on the discharge side of each compressor. The separated oil is returned to one of the compressors that has run out of oil (for example, JP-A-4-184048).

[0003] Oil shortage of the compressor is detected by an oil sensor, which detects oil shortage by detecting the oil level.

[0004]

However, in the prior art, (1) the oil separated by the oil separator is returned to the compressor, so that it takes time to separate the oil, and the amount of oil returned per hour is reduced. . (2) When the capacity of the compressor is different and the operating capacity of the compressor with the larger oil amount is low (for example, an inverter compressor), the oil discharge amount is generally small, so the oil amount is small. , The amount of oil returned to the compressor with less oil is reduced. (3) The number of oil sensors and solenoid valves corresponding to the number of compressors is required, resulting in a problem such as an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air conditioner which solves the above-mentioned problems of the prior art and has a simple structure and which can quickly return oil to a compressor having insufficient oil. It is in.

[0006]

According to the first aspect of the present invention,
In a refrigerating apparatus in which a plurality of compressors having a high-pressure vessel structure are connected in parallel, an oil balance pipe derived from the high-pressure vessel of the compressor is connected to a suction pipe of another compressor via a pressure reducer.
And when one compressor runs for a certain period of time,
Operate two compressors connected by oil balance pipe for a predetermined time
During this period, they are operated simultaneously .

According to a second aspect of the present invention, in a refrigeration system in which a plurality of compressors having a high-pressure vessel structure are connected in parallel, an oil balance pipe derived from the high-pressure vessel of the compressor is connected to another compressor through a pressure reducer. And the compressor
Are connected by an oil equalizing pipe, and one compressor operates
After a fixed time, two compressors connected by oil equalizing pipe
Are simultaneously stopped for a predetermined time . Claim
The invention according to claim 3 is the invention according to claim 1 or 2,
Depressurize the oil balance pipe led out of the high pressure vessel of the compressor
Vertical extension of the suction pipe of another compressor through the compressor
Connected to a pipe.

[0008]

According to the first or second aspect of the present invention, by utilizing the fact that the internal pressure of the high-pressure vessel is high, the compressor having the higher oil level can pass through the oil balance pipe and the capillary tube. The oil is sent out to the suction pipe of the other compressor and the oil is returned to the high-pressure container of the compressor. According to this, the compressor operates
Inside, the oil from the compressor pressure vessel with excess oil
Oil is returned to the compressor pressure vessel
Automatically eliminates the imbalance in oil volume between compressors
Is done.

According to the third aspect of the present invention, the oil is pressurized.
Return to the vertical pipe of the suction pipe of the compressor,
The oil returns when the compressor stops and the accumulator
The next time the compressor starts up, the oil will
It is reliably sucked into the compressor and returned into its high-pressure vessel.

According to the second aspect of the present invention, the oil is returned to the upright pipe extending in the vertical direction of the suction pipe of the compressor, so that the oil returned when the compressor is stopped is returned to the accumulator by gravity. When the machine is started, the oil is reliably sucked into the compressor and returned to the high pressure vessel.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the air conditioner according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an outdoor unit. A plurality of indoor units 9 are connected to the outdoor unit 1 via two pipes 3 and 5.

First, the outdoor unit 1 will be described. Compressors (for example, rotary compressors) 11 and 13 having two high-pressure vessel structures connected in parallel, and a four-way valve 15 are provided.
, A heat exchanger 17, an electronic control valve 19, a receiver tank 21, an accumulator 23, and auxiliary accumulators 25 and 27. 29, 31
Is a check valve. The compressors 11 and 13 may be variable in capacity, one of them may be rated, or both may be rated. The capacities may be different from each other.

The indoor unit 9 will be described. An indoor heat exchanger 35 and an electronic control valve (indoor mechanical valve) 37 are provided.
Each indoor unit 9 is installed in a separate room. As described later, this air conditioning system is a system capable of performing a cooling operation or a heating operation of each room.

Thus, according to this embodiment, there is a feature in the structure of how to balance the amount of oil between the compressors 11 and 13 having the structure of two high pressure vessels.

Referring to FIG. 2, high-pressure vessel 1 of compressor 11
01 is connected to one end 201a of an oil balance pipe 201, and the other end 201b is connected to a suction pipe 13a of another compressor 13 via a capillary tube (decompressor) 41. One end 203a of an oil balance pipe 203 is connected to the high-pressure container 103 of the compressor 13, and the other end 203b is connected to a capillary tube (decompressor).
It is connected to the suction pipe 11a of another compressor 11 via 43. 220 is a reference oil surface.

Also, the other end 201b of the oil balance pipe,
203b is an accumulator 23 as shown in FIG.
Of the suction pipes 11a and 13a that are connected to a vertical pipe 51 extending in the vertical direction. According to this, since the oil return when the compressors 11 and 13 are stopped is returned to the accumulator 23 by gravity, the next compressor 11 and 13 is stopped.
At the startup of the compressor 13, the oil is completely removed from the compressors 11, 13
And is returned to the high-pressure vessel.

Next, the operation of the air conditioner will be described.

A: Cooling operation Referring to FIG. 1, when the four-way valve 15 is switched to the position indicated by the solid line, the refrigerant discharged from each of the compressors 11 and 13 causes the four-way valve 15 to operate as indicated by the solid line arrow. After passing through, it enters the heat exchanger 17, passes through the electronic control valve 19, the receiver tank 21, passes through the electronic control valve (indoor mechanical valve) 37 of the indoor unit 9,
It passes through the indoor heat exchanger 35, passes through the four-way valve 15, passes through the accumulator 23, the auxiliary accumulators 25 and 27, and returns to the compressors 11 and 13.

At this time, the indoor heat exchanger 35 acts as an evaporator, and cool air is blown into the room.

B; Heating Operation Referring to FIG. 1, when the four-way valve 15 is switched to the position indicated by the dotted line, the refrigerant discharged from each of the compressors 11 and 13 causes the four-way valve 15 to operate as indicated by the dotted line arrow. After passing, the indoor heat exchanger 35 of the indoor unit 9 and the electronic control valve (indoor mechanical valve)
After passing through 37, it enters the receiver tank 21, the electronic control valve 19, and the heat exchanger 17, passes through the four-way valve 15, passes through the accumulator 23, the auxiliary accumulators 25, 27, and returns to the compressors 11, 13.

At this time, the indoor heat exchanger 35 acts as a condenser, and warm air is sent out into the room.

Next, the operation of this embodiment will be described.

During the operation of the above-described air conditioner, it is desirable that substantially the same amount of oil be returned to the high-pressure vessels 101 and 103 of the compressors 11 and 13. However, in practice, the return amount of the oil during operation is offset, and the oil level of each of the high-pressure vessels 101 and 103 is unbalanced.
For example, referring to FIG. 2, if the oil level of the high pressure vessel 101 of one compressor 11 rises, the other compressor 1
The oil level of the high-pressure container 103 of No. 3 falls.

In this case, according to this embodiment, since the pressure in each of the high-pressure vessels 101 and 103 is high, the oil in the high-pressure vessel 101 of one of the compressors 11 is pushed out by the high pressure, and the oil balance pipe 201 and the suction tube 13 of another compressor 13 via the capillary tube 41
a and is collected in the high-pressure vessel 103 of the compressor 13.

The high pressure vessel 103 of the other compressor 13
If the oil level inside rises, the oil in the high-pressure vessel 103 of the other compressor 13 is pushed out by the high pressure, and conversely through the oil balance pipe 203 and the capillary tube 43, And is collected in the high-pressure vessel 101 of the compressor 11.

That is, according to this embodiment, the high pressure vessel 1
Utilizing the fact that the internal pressure of 01 and 103 is high,
The oil is sent out from the compressor with the raised oil level to the suction pipe of the other compressor through the oil balance pipe and the capillary tube to return the oil to the high-pressure container of the compressor. is there. According to this,
First, there is no need to provide an oil separator on the discharge side of the compressor, provide an oil sensor for the compressor, or provide a solenoid valve for the oil return pipe, as in the past.
Manufacturing costs can be significantly reduced.

In particular, since the oil separator can be omitted, no time is required for separating the oil, and the oil is returned directly to the compressor.
The amount of oil returned can be increased.

According to this structure, the high-pressure vessels 101, 10
The oil in 3 is returned to the suction pipes 11a and 13a of the compressors 11 and 13 through the oil balance pipes 201 and 203, that is, since the pressure difference between the high-pressure vessel and the suction pipe is extremely large, quick oil return is achieved. At the same time, even if there is a difference between the internal pressures of the two high-pressure vessels 101 and 103, quick oil return is performed.

According to the configuration of this embodiment, when balancing oil, it is necessary that both compressors 11 and 13 are operated. However, a plurality of indoor units 9
Of one of the compressors 11 and 13
May shut down for a long time. In this case, even if the oil surfaces in the high-pressure vessels 101 and 103 are offset, the oil amount cannot be balanced.

To solve this problem, the following control is performed.

(1) If one compressor operates for a predetermined time (for example, 5 hours), two compressors are forcibly operated simultaneously for a predetermined time (for example, about 1 minute). Then, through the oil balance pipes 201 and 203,
Since the oil is returned to the compressor having insufficient oil, the imbalance of the oil amount is eliminated.

(2) In another embodiment, the high pressure vessels 101 and 103 of the two compressors 11 and 13 are connected by an oil equalizing pipe (not shown), and one of the compressors is operated. After the continuation, if a predetermined time (for example, 5 hours) has elapsed, the two compressors may be stopped simultaneously for a predetermined time (for example, about 1 minute). With this configuration, the oil is returned to the oil-deficient compressor by the gravity action through the oil equalizing pipe, so that the imbalance of the oil amount is eliminated.

Although the present invention has been described with reference to one embodiment, it is apparent that the present invention is not limited to this.

For example, in the above-described embodiment, the number of compressors is two. However, even if three or more compressors are connected in parallel, this method can be adopted.

When three compressors A, B, and C are connected in parallel, for example, an oil balance pipe derived from the high-pressure vessel of the first compressor A is connected to the second compressor A via a pressure reducer. The third compressor C is connected to the suction pipe of the third compressor C via a pressure reducer, and the oil balance pipe derived from the high pressure vessel of the second compressor B is connected to the suction pipe of the compressor B. What is necessary is just to connect the oil balance pipe derived from the high-pressure container of C to the suction pipe of the first compressor A via a pressure reducer.

[0037]

As is apparent from the above description, the claims
According to the invention described in 1 or 2, the oil balance pipe drawn out of the high pressure vessel of the compressor is connected to the suction pipe of another compressor via the decompressor. Oil is sent out from the compressor that has risen to the suction pipe of the other compressor, and the oil is returned to the high-pressure vessel of that compressor, which eliminates the imbalance in oil volume between the compressors. You.

According to the third aspect of the present invention, the oil balance pipe derived from the high pressure vessel of the compressor is connected to the vertical pipe of the suction pipe of the other compressor via the decompressor. The oil returned when the compressor is stopped is returned to the accumulator by gravity, so the next time the compressor is started, the oil is completely sucked into the compressor and returned to the high-pressure container, so that the oil amount is unbalanced. Is eliminated.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of an embodiment of a refrigeration apparatus (air conditioner) according to the present invention.

FIG. 2 is a refrigerant circuit diagram showing a main part of the refrigerant circuit of FIG. 1;

FIG. 3 is a plan view showing a connection state of an oil balance pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outdoor unit 9 Indoor unit 11, 13 Compressor 11a, 13a Suction pipe 41, 43 Capillary tube (decompressor) 51 Stand tube 101, 103 High pressure vessel 201, 203 Oil balance pipe

Claims (3)

(57) [Claims] In a refrigeration system in which a plurality of compressors having a high-pressure vessel structure are connected in parallel, an oil balance pipe derived from the high-pressure vessel of the compressor is connected to a suction pipe of another compressor via a pressure reducer. And one compressor runs for a certain period of time
If the pressure has passed, the two pressures connected by the oil balance pipe
A refrigeration system wherein the compressor is operated simultaneously for a predetermined time . 2. A refrigerating apparatus in which a plurality of compressors having a high-pressure vessel structure are connected in parallel, wherein an oil balance pipe derived from the high-pressure vessel of the compressor is connected to a suction pipe of another compressor via a pressure reducer. Oil equalizing pipe between the high pressure vessel of the compressor
If one compressor runs for a certain period of time,
Simultaneously operate two compressors connected by oil equalizing pipes for a predetermined time.
A refrigeration apparatus characterized by being stopped at a time . 3. An oil outlet derived from a high pressure vessel of the compressor.
Through a pressure reducer to the suction pipe of another compressor.
A contractor characterized by being connected to a vertical pipe extending in the vertical direction.
The refrigeration apparatus according to claim 1 or 2.