JP2001329958A - Oil equalizing system for plural compressors - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately control the oil quantities for plural compressors. SOLUTION: This system is provided with a constant-speed side oil returning main bypass 12 for communicating an oil exhaust port of a constant-speed side oil separator 6 with a suction collective tube 11. The oil is fed from the constant-speed side oil separator 6 to a variable-speed compressor 1 to prevent the shortage of the oil quantity when the variable-speed compressor 1 is operated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil equalizing system for a plurality of compressors.

[0002]

2. Description of the Related Art A conventional oil level control system for a plurality of compressors is disclosed in Japanese Patent Application Laid-Open No. 5-71822.

Hereinafter, the oil equalizing system for a plurality of compressors will be described with reference to the drawings.

In FIG. 5, reference numeral 1 denotes a variable speed compressor,
2 is a constant speed compressor. 5 is a variable speed discharge pipe 3
Reference numeral 6 denotes a constant speed oil separator provided in the constant speed discharge pipe 4. Reference numeral 7 denotes a variable speed oil return bypass which communicates the oil discharge port of the variable speed oil separator 5 with the variable speed suction pipe 9. The variable speed oil return bypass communicates with the high speed suction pipe 10.

[0005] Incidentally, two constant speed compressors 2 are connected in the conventional example, and suffixes a and b are added to distinguish them.

Next, a description will be given of a compressor oil equalizing method in the multiple compressor oil equalizing system having the above-described configuration.

First, oil contained in the refrigerant discharged from the variable speed compressor 1 is separated from the refrigerant by the variable speed oil separator 5, passes through the variable speed oil return bypass 7, and passes through the variable speed suction pipe 9. Is returned to the variable speed compressor 1 via the

The oil contained in the refrigerant discharged from the constant speed compressor 2 is separated from the refrigerant by a constant speed oil separator 6, passes through a constant speed oil return bypass 8, and passes through each constant speed suction pipe. It is returned to the constant speed compressor 2 via 10.

As described above, by returning the oil contained in the refrigerant discharged from the compressor to the compressor that has discharged the oil, the amount of oil in each compressor is controlled to an appropriate amount.

[0010]

However, it is difficult to separate all the oil from the refrigerant by the oil separators 5, 6a, 6b, and the oil separators 5, 6a, 2b discharged from the compressors 1, 2a, 2b. A part of the oil that cannot be separated in the compressor 6b joins in a cycle, and then the suction pipes 9 and 10 of the compressors 1, 2a and 2b pass through the suction collecting pipe 11.
A is returned to each of the compressors 1, 2a, 2b via a, 10b.

Therefore, in the above configuration, when the variable speed compressor 1 operates at a high speed, a large amount of oil flowing out of the variable speed compressor 1 into the cycle is reduced by a small amount of oil flowing out of the constant speed compressor 2 into the cycle. After merging with the oil, the oil is returned not only to the variable speed compressor 1 but also to the constant speed compressor 2 from the suction collecting pipe 11 via the variable speed suction pipe 9 and the constant speed suction pipe 10. For this reason, there has been a problem that the oil amount of the variable speed compressor 1 continues to decrease, and the oil amount becomes insufficient.

An object of the present invention is to solve the conventional problem and to provide an oil equalizing system for a plurality of compressors with a simple configuration.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a variable speed oil return bypass for communicating an oil discharge port of a variable speed oil separator with a variable speed suction pipe, and an oil discharge bypass for all constant speed oil separators. A constant-speed-side oil return main bypass for communicating the outlet with the suction collecting pipe is provided.

A variable speed oil return bypass for communicating the oil outlet of the variable speed oil separator with the variable speed suction pipe, and a communication between the oil outlets of all the constant speed oil separators and the suction collecting pipe. A constant-speed-side oil return main bypass, and a constant-speed-side oil return sub-bypass for communicating the constant-speed-side oil separator with each of the constant-speed-side suction pipes.

The constant-speed-side oil return main bypass includes:
A two-way valve capable of closing the communication between the oil discharge port of each constant speed side oil separator and the suction collecting pipe is provided, and when the variable speed compressor operates at a high speed, the two-way valve is opened and the variable speed compressor is opened. When the compressor operates at a low speed, the compressor is provided with a two-way valve control means for closing the two-way valve.

According to the present invention, the oil amount of the compressor can be reliably controlled to an appropriate amount in any use condition.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is directed to an air conditioner equipped with a variable speed compressor and a plurality of constant speed compressors, wherein a variable speed side oil separator is provided with a variable speed side oil separator. A constant speed side oil separator in the constant speed side discharge pipe, a variable speed side oil return bypass for communicating an oil outlet of the variable speed side oil separator with the variable speed side suction pipe, and all the constant speed side oil return bypasses. A constant-speed-side oil return main bypass for communicating the oil discharge port of the side oil separator with the suction collecting pipe.

With this configuration, part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator moves from the suction collecting pipe to the variable speed compressor via the variable speed suction pipe. Therefore, when the variable speed compressor operates at a high speed, the variable speed compressor has an effect of being able to prevent an insufficient oil amount.

According to a second aspect of the present invention, there is provided an air conditioner equipped with a variable speed compressor and a plurality of constant speed compressors, wherein the variable speed discharge pipe includes a variable speed oil separator, A variable-speed oil return bypass that connects a constant-speed oil separator to the variable-speed oil separator and an oil outlet of the variable-speed oil separator and a variable-speed suction pipe. A constant-speed-side oil return main bypass for communicating the oil discharge port with the suction collecting pipe, and a constant-speed-side oil return auxiliary bypass for communicating the oil discharge port of the constant-speed oil separator with each of the constant-speed suction pipes. It is provided.

With this configuration, part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator moves from the suction collecting pipe to the variable speed compressor via the variable speed suction pipe. Therefore, when the variable speed compressor operates at a high speed, the variable speed compressor has an effect of being able to prevent an insufficient oil amount.

Further, a part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator is separated by the constant speed oil return sub-bypass.
It is returned to each constant speed compressor via the constant speed side suction pipe. For this reason, even when a large amount of oil is discharged from the constant-speed compressor, such as when the constant-speed compressor is started, it is possible to prevent the shortage of the oil amount of the constant-speed compressor due to a sharp decrease in the oil amount of the constant-speed compressor. It has the action of:

According to a third aspect of the present invention, in addition to the configuration according to the second aspect, an oil discharge port of each of the constant speed side oil separators and a suction collecting pipe are provided in the constant speed side oil return main bypass. A two-way valve capable of closing the communication with the valve, and furthermore, the two-way valve is opened when the variable speed compressor operates at high speed, and the two-way valve is opened when the variable speed compressor operates at low speed. It is provided with a two-way valve control means for closing.

With this configuration, when the variable speed compressor operates at a high speed, the two-way valve is open, so that the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed side oil separator. A part moves from the suction collecting pipe to the variable speed compressor via the variable speed side suction pipe, and has an effect that an oil amount shortage of the variable speed compressor can be prevented.

Further, a part of the oil separated from the refrigerant discharged from the constant-speed compressor by the constant-speed oil separator is separated by the constant-speed oil return sub-bypass.
It is returned to each constant speed compressor via the constant speed side suction pipe. For this reason, even when a large amount of oil is discharged from the constant-speed compressor, such as when the constant-speed compressor is started, it is possible to prevent the shortage of the oil amount of the constant-speed compressor due to a sharp decrease in the oil amount of the constant-speed compressor. It has the action of:

Further, when the variable speed compressor operates at low speed, the two-way valve is closed, so that the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator is acceptable. It does not move to the variable speed compressor. Therefore, even when the amount of oil flowing out of the variable speed compressor to the cycle due to the low speed operation is reduced, the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator moves to the variable speed compressor. Therefore, an excessive amount of oil of the variable speed compressor can be prevented.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same parts as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 12 denotes a constant-speed-side oil return main bypass for communicating the oil discharge port of the constant-speed-side oil separator 6 with the suction collecting pipe 11.

According to this embodiment, a part of the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed oil separator 6 is transferred to the constant speed oil return main bypass 1.
By 2, it moves from the suction collecting pipe 11 to the variable speed compressor 1 via the variable speed side suction pipe 9. For this reason, even when the variable speed compressor 1 operates at high speed and a large amount of oil flows out into the cycle, the variable speed compressor 1 is supplied with oil from the constant speed side oil separator 6, so that the variable speed compressor 1 1
Oil shortage can be prevented.

In this way, the oil amount of the compressor can be controlled to an appropriate amount.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG.

FIG. 2 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 2 of the present invention.

In FIG. 2, reference numeral 13 denotes a constant speed side oil return main bypass for communicating the oil discharge port of the constant speed side oil separator 6 with the suction collecting pipe 11. Reference numeral 14 denotes a constant-speed-side oil return sub-bypass that allows the oil discharge port of the constant-speed-side oil separator 6 to communicate with each of the constant-speed-side suction pipes 10.

According to this embodiment, a part of the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed oil separator 6 is transferred to the constant speed oil return main bypass 13.
As a result, the compressor moves from the suction collecting pipe 11 to the variable speed compressor 1 via the variable speed side suction pipe 9. Therefore, the variable speed compressor 1
Performs high-speed operation and causes a large amount of oil to flow out into the cycle, the oil is supplied from the constant-speed oil separator 6 to the variable-speed compressor 1, so that the variable-speed compressor 1 can be prevented from running out of oil. .

Further, the constant speed side oil separator 6
A part of the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed side oil return sub-bypass 14
It is returned to each constant speed compressor 2 via the constant speed side suction pipe 10. Therefore, even when a large amount of oil is discharged from the constant-speed compressor 2 such as when the constant-speed compressor 2 is started, the oil amount of the constant-speed compressor 2 due to a sharp decrease in the oil amount of the constant-speed compressor 2 is increased. It has the effect that shortage can be prevented.

Thus, the oil amount of the compressor can be controlled to an appropriate amount.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIGS.

FIG. 3 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 3 of the present invention.

In FIG. 3, reference numeral 15 denotes a constant-speed-side oil return main bypass for communicating the oil discharge port of the constant-speed-side oil separator 6 with the suction collecting pipe 11. Reference numeral 16 denotes a two-way valve provided in the middle of the constant speed side oil return main bypass 15 so that the communication between the oil discharge port of the constant speed side oil separator 6 and the suction collecting pipe 11 can be closed. is there. Here, the two-way valve control means 17 opens the two-way valve 16 when the variable speed compressor 1 operates at high speed, and closes the two-way valve when the variable speed compressor 1 operates at low speed. . Further, in this embodiment, the variable speed compressor 1 is assumed to be an inverter compressor.

FIG. 4 is a flowchart showing a method for controlling the two-way valve 16 in the oil equalizing system for a plurality of compressors according to the third embodiment of the present invention.

Referring to FIG. 4, when the compressor starts operating, first, in step 1, the two-way valve 16 is opened. Step 2
Then, the operating frequency Fi of the variable speed compressor 1 is detected. In step 3, if the variable speed compressor operating frequency Fi detected in step 2 is equal to or higher than the reference frequency Fio (for example, 60 Hz), the process returns to step 1, and if it is lower than the reference frequency Fio, the process proceeds to step 4. In step 4, the two-way valve 16
And returns to step 2.

According to this embodiment, when the variable speed compressor 1 operates at a high speed, the two-way valve 16 is opened, so that the constant speed compressor 2
A part of the oil separated from the discharged refrigerant passes through the constant speed oil return main bypass 15 and moves from the suction collecting pipe 11 to the variable speed compressor 1 via the variable speed suction pipe 9. For this reason, even when the variable speed compressor 1 operates at high speed and a large amount of oil flows out to the cycle, the variable speed compressor 1 is supplied with oil from the constant speed side oil separator 6. Oil shortage can be prevented.

Furthermore, the constant speed side oil separator 6
A part of the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed side oil return sub-bypass 14
It is returned to each constant speed compressor 2 via the constant speed side suction pipe 10. Therefore, even when a large amount of oil is discharged from the constant-speed compressor 2 such as when the constant-speed compressor 2 moves, the oil amount of the constant-speed compressor 2 due to a sharp decrease in the oil amount of the constant-speed compressor 2 It has the effect that shortage can be prevented.

Further, when the variable speed compressor 1 operates at a low speed, the two-way valve 16 is closed, so that the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed oil separator 6 is used. Does not move to the variable speed compressor 1. Therefore, even when the amount of oil flowing out of the variable speed compressor 1 to the cycle due to the low speed operation is reduced, the oil separated from the refrigerant discharged from the constant speed compressor 2 by the constant speed oil separator 6 is removed. To prevent the oil amount of the variable speed compressor 1 from being excessive.

In this way, the oil amount of the compressor can be controlled to an appropriate amount.

[0047]

As described above, the invention according to claim 1 is
A variable speed oil return bypass for communicating the oil outlet of the variable speed oil separator with the variable speed suction pipe, and a constant speed oil for communicating the oil outlets of all the constant speed oil separators with the suction collecting pipe. It is equipped with a return main bypass, and a part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator is transferred from the suction collecting pipe to the variable speed compressor through the variable speed suction pipe. Since the variable speed compressor moves, it is possible to prevent the oil amount of the variable speed compressor from being insufficient when the variable speed compressor operates at a high speed, and to control the oil amount of the compressor to an appropriate amount.

The second aspect of the present invention provides a variable speed oil return bypass for communicating an oil discharge port of a variable speed oil separator with a variable speed suction pipe, and an oil drain bypass of all constant speed oil separators. A constant speed side oil return main bypass for communicating the outlet with the suction collecting pipe, and a constant speed side oil return auxiliary bypass for communicating the oil discharge port of the constant speed side oil separator with each constant speed side suction pipe. A part of the oil separated from the refrigerant discharged from the constant-speed compressor by the constant-speed oil separator moves from the suction collecting pipe to the variable-speed compressor via the variable-speed suction pipe. Insufficient oil amount of the variable speed compressor when the compressor operates at high speed.

Further, a part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator passes through the constant speed oil return sub-bypass and passes through each constant speed suction pipe. Returned to the constant speed compressor. For this reason, even when a large amount of oil is discharged from the constant-speed compressor, such as when the constant-speed compressor is started, it is possible to prevent the shortage of the oil amount of the constant-speed compressor due to a sharp decrease in the oil amount of the constant-speed compressor. .

In this way, the oil amount of the compressor can be controlled to an appropriate amount.

According to a third aspect of the present invention, the fixed speed side oil return main bypass is provided with a two-way valve capable of closing the communication between the oil discharge port of each fixed speed side oil separator and the suction collecting pipe. When the variable speed compressor operates at high speed, the two-way valve is opened. When the variable speed compressor operates at low speed, the two-way valve is closed. For this reason, when the variable speed compressor operates at high speed, the two-way valve is open, so that a part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator is sucked. By moving from the collecting pipe to the variable speed compressor via the variable speed suction pipe, it is possible to prevent the variable speed compressor from having an insufficient amount of oil.

Further, a part of the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator passes through the constant speed oil return sub-bypass and passes through each constant speed suction pipe. Returned to the constant speed compressor. For this reason, even when a large amount of oil is discharged from the constant-speed compressor, such as when the constant-speed compressor is started, it is possible to prevent the shortage of the oil amount of the constant-speed compressor due to a sharp decrease in the oil amount of the constant-speed compressor. .

Further, when the variable speed compressor operates at a low speed, the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator is controlled by the constant speed oil separator because the two-way valve is closed. It does not move to the compressor. Therefore, even when the amount of oil flowing out of the variable speed compressor to the cycle due to the low speed operation decreases, the oil separated from the refrigerant discharged from the constant speed compressor by the constant speed oil separator moves to the variable speed compressor. However, an excessive oil amount of the variable speed compressor can be prevented.

In this way, the oil amount of the compressor can be controlled to an appropriate amount.

[Brief description of the drawings]

FIG. 1 is a structural diagram of an oil equalizing system for a plurality of compressors according to a first embodiment of the present invention.

FIG. 2 is a structural diagram of an oil equalizing system for a plurality of compressors according to a second embodiment of the present invention.

FIG. 3 is a structural diagram of an oil equalizing system for a plurality of compressors according to a third embodiment of the present invention.

FIG. 4 is a flowchart illustrating a control method of a two-way valve of the oil equalizing system for a plurality of compressors according to the third embodiment of the present invention.

FIG. 5 is a structural diagram of a conventional oil equalizing system for a plurality of compressors.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable speed compressor 2 Constant speed compressor 3 Variable speed side discharge pipe 4 Constant speed side discharge pipe 5 Variable speed side oil separator 6 Constant speed side oil separator 7 Variable speed side oil return bypass 8 Constant speed side oil return bypass 9 Possible Speed change side suction pipe 10 Constant speed side suction pipe 11 Suction collecting pipe 12, 13, 15 Constant speed side oil return main bypass 14 Constant speed side oil return auxiliary bypass 16 Two-way valve 17 Two-way valve control means

Claims (3)

[Claims] 1. An air conditioner equipped with a variable speed compressor and a plurality of constant speed compressors, wherein a variable speed side discharge pipe is provided with a variable speed side oil separator and a constant speed side discharge pipe is provided with a constant speed side oil separator. A variable speed oil return bypass for communicating an oil outlet of the variable speed oil separator with the variable speed suction pipe, and a communication between the oil outlets of all the constant speed oil separators and the suction collecting pipe. Oil equalization system for multiple compressors with a constant speed oil return main bypass. 2. An air conditioner equipped with a variable speed compressor and a plurality of constant speed compressors, wherein the variable speed discharge pipe includes a variable speed oil separator, and the constant speed discharge pipe includes a constant speed oil separator. A variable speed oil return bypass for communicating an oil outlet of the variable speed oil separator with the variable speed suction pipe, and a communication between the oil outlets of all the constant speed oil separators and the suction collecting pipe. An oil equalizing system for a plurality of compressors, comprising: a constant-speed-side oil return main bypass to be connected; 3. A constant-speed side oil return main bypass is provided with a two-way valve capable of closing a communication between an oil discharge port of each of the constant-speed side oil separators and a suction collecting pipe, and further comprising a variable speed compressor having a high speed. 3. The oil equalizing system according to claim 2, further comprising a two-way valve control unit that opens the two-way valve when the operation is performed, and closes the two-way valve when the variable speed compressor performs the low-speed operation. .