JP2002286302A - Refrigerant circuit equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain refrigerant circuit equipment capable of precisely obstructing the mix of refrigerant into an oil tank storing the oil separated by an oil separator. SOLUTION: Refrigerant circuit equipment is provided with oil separators 2a and 2b for separating the oil from the discharged refrigerant of a plurality of compressors 1a to 1d that are connected in parallel, and an oil tank 9 storing the oil separated by the oil separators 2a and 2b and having oil feeders 10a to 10d controlling the feed of oil to the compressors 1a to 1d from the oil tank 9 according to the height of the oil level of the compressors 1a to 1d. There are provided oil-circuit electromagnetic valves 20a and 20b opening and closing the circuits between the oil separators 2a, 2b and the oil tank 9 according to the operation/stop of the compressors 1a to 1d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant circuit for cooling a plurality of showcases and refrigerators having different cooling temperatures depending on products such as a supermarket.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional refrigerant circuit system equipped with a plurality of compressors, an oil separator, an oil tank and an oil supply connected in parallel. In the figure, 1a to 1d are compressors, 2
a to 2b are oil separators, 3a to 3d are condensers, 4 is a liquid receiver, 5a to 5d are expansion valves, 6a to 6d are cooling devices, 7a
7b are accumulators, and 8 is a refrigerant pipe communicating these. Also, as a circuit for returning the oil separated by the oil separator to the compressor, 9 is an oil tank, and 10a to 10d are oil feeders.

Next, the operation of the conventional equipment will be described with reference to FIG. The high-temperature, high-pressure oil-containing gas refrigerant compressed by the compressors 1a and 1b joins and is connected to one oil separator 2a. Similarly, high-temperature, high-pressure oil-containing gas refrigerant compressed by the compressors 1c to 1d joins and is connected to one oil separator 2b. The refrigerant from which the oil has been separated by the oil separator 2a and the oil separator 2b is joined, and then the condenser 3a
Ｄ3d, radiated, condensed, liquefied and stored in the liquid receiver 4. The liquid refrigerant flowing out of the receiver 4 is expanded by the expansion valves 5a to 5d.
After the pressure is reduced, the heat is absorbed and evaporated by the cooling devices 6a to 6d. The refrigerant flowing out of the cooling devices 6a to 6d is diverted to the accumulators 7a to 7b and separated into gas and liquid. The gas refrigerant that has exited the accumulator 7a is further divided into compressors 1a to 1b
, And the cycle that the gas refrigerant that has exited the accumulator 7b is further divided and returned to the compressors 1c to 1d is repeated. On the other hand, the oil separated by the oil separators 2a to 2b is temporarily stored in the oil tank 9, and returned to the compressors 1a to 1d as required by the operation of the oil supply units 10a to 10d. The compressors 1a to 1d perform a capacity control operation by operating / stopping.

[0004]

There is a two-compressor operation in which the compressors 1a to 1d perform a displacement control operation and only the compressors 1a to 1b operate. In this case, the refrigerant discharged from the compressors 1a to 1b merges and separates oil in the oil separator 2a, and then splits to the condensers 3a to 3d. Flows into. The gas refrigerant that has flowed in may be cooled due to a decrease in outside air temperature or the like, and may become a liquid refrigerant and fall asleep. The liquid refrigerant stored in the oil separator 2b flows into the oil tank 9 through the communication pipe 8b.

On the other hand, the amount of oil taken out of the compressor from the compressor is largest when the compressor is started from a stopped state, and when the oil level in the compressor is lowered, the amount of oil taken out is stored in the oil tank by the operation of the oil supply device. The supplied oil is supplied to each compressor.

[0006] When the operation of the compressor is shifted from the operation of two compressors to the operation of three compressors due to an increase in the load of the cooling device, a large amount of oil is taken out of the compressor by starting the compressor 1c.
Oil level drops. In addition, the amount of oil stored in the oil tank 9 by the action of the oil supply device is increased by the amount corresponding to the decrease in oil level.
However, as described above, since the liquid refrigerant is stored in the oil tank 9, not only oil but also oil containing a large amount of liquid refrigerant is supplied to the compressor.

[0007] Originally, oil retained for lubrication inside the compressor is mixed with a large amount of liquid refrigerant supplied from an oil tank, and the oil concentration is reduced. A decrease in the oil concentration leads to a decrease in the lubrication function, and in the worst case, a compressor failure such as shaft seizure may occur.

SUMMARY OF THE INVENTION The present invention has an object to provide a refrigerant circuit equipment capable of accurately preventing refrigerant from being mixed into an oil tank for storing oil separated by an oil separator.

[0009]

A first aspect of the present invention is the first aspect.
In the refrigerant circuit equipment according to the invention, a plurality of compressors connected in parallel, an oil separator for separating oil from refrigerant discharged from the compressor, an oil tank for storing oil separated by the oil separator. A refrigerant circuit device having an oil supply device for controlling oil supply from the oil tank to the compressor in accordance with the height of the oil level of the compressor. An oil circuit opening / closing means for opening / closing a circuit between the oil separator and the oil tank is provided.

In the refrigerant circuit equipment according to a second aspect of the present invention, a plurality of compressors connected in parallel, and a plurality of oil separators for separating oil from refrigerant discharged from the compressors. A refrigerant circuit having an oil tank for storing oil separated by the oil separator, and an oil supply device for controlling oil supply from the oil tank to the compressor according to the height of the oil level of the compressor. In the equipment, oil circuit opening / closing means for closing a circuit between the oil tank and the oil separator corresponding to the compressor stopped operating when at least one of the compressors is operated.

In the refrigerant circuit equipment according to a third aspect of the present invention, the first and second and third and fourth compressors connected in parallel, and the first and second compressors are connected to each other. A first oil separator that receives refrigerant discharged from the first and second compressors to separate oil from discharged refrigerant; and a first oil separator that separates oil from refrigerant discharged from the third and fourth compressors. A second receiving the refrigerant discharged from the third and fourth compressors;
Oil separator, an oil tank for storing oil separated by the first and second oil separators, and oil supply from the oil tank to the compressor according to the height of the oil level of the compressor In the refrigerant circuit equipment having an oil supply controlling the
Closing a circuit between the second oil separator and the oil tank corresponding to the third and fourth compressors that are stopped when at least one of the first and second compressors is operating. A first oil circuit opening / closing means for opening a circuit between the second oil separator and the oil tank when at least one of the third and fourth compressors is operated; And closing a circuit between the first oil separator and the oil tank corresponding to the first and second compressors that have stopped operating during operation of at least one of the fourth compressors, At least one of the first and second compressors
A second oil circuit opening / closing means for opening a circuit between the first oil separator and the oil tank during operation of the table is provided.

According to a fourth aspect of the present invention, in the refrigerant circuit equipment according to the fourth aspect, in the first to third aspects, a solenoid valve is used as the oil circuit opening / closing means.

According to a fifth aspect of the present invention, there is provided a refrigerant circuit equipment comprising: a plurality of compressors connected in parallel; an oil separator for separating oil from refrigerant discharged from the compressor; A refrigerant circuit device comprising an oil tank that stores oil separated by a separator, and an oil supply device that controls oil supply from the oil tank to the compressor according to the height of the oil level of the compressor, The oil separator is provided with a heater for operating / stopping the compressor in accordance with the operation / stop of the compressor.

In the refrigerant circuit equipment according to a sixth aspect of the present invention, a plurality of compressors connected in parallel, and a plurality of oil separators for separating oil from refrigerant discharged from the compressors. A refrigerant circuit having an oil tank for storing oil separated by the oil separator, and an oil supply device for controlling oil supply from the oil tank to the compressor according to the height of the oil level of the compressor. The facility is provided with a heater means for heating and operating an oil separator corresponding to the compressor stopped operating when at least one of the compressors is operated.

In the refrigerant circuit equipment according to a seventh aspect of the present invention, the first and second and third and fourth compressors connected in parallel, and the first and second compressors are connected to each other. A first oil separator that receives refrigerant discharged from the first and second compressors to separate oil from discharged refrigerant; and a first oil separator that separates oil from refrigerant discharged from the third and fourth compressors. A second receiving the refrigerant discharged from the third and fourth compressors;
Oil separator, an oil tank for storing oil separated by the first and second oil separators, and oil supply from the oil tank to the compressor according to the height of the oil level of the compressor In the refrigerant circuit equipment having an oil supply controlling the
While operating at least one of the first and second compressors, the second oil separators connected to the third and fourth compressors, which are stopped operating, are heated, and the third oil separator is heated.
And first heater means for stopping heating when at least one of the fourth and fourth compressors is operated, and stopping the operation when at least one of the third and fourth compressors is operated. Heating the first oil separator connected to the first and second compressors, and stopping heating when at least one of the first and second compressors is operated;
Is provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram showing a refrigerant circuit equipment according to a first embodiment of the present invention, wherein 1 to 10 are all the same as conventional equipment, and 20a to 20b are oil circuit opening / closing means including oil circuit solenoid valves. Is shown.

Next, the refrigerant circuit equipment in this embodiment will be described. First, regarding the opening and closing of the oil circuit solenoid valve, the oil circuit solenoid valve 20a opens when one or both of the compressors 1a and 1b are operating, and closes the others. Similarly, the oil circuit solenoid valve 20b is also used for the compressor 1
When any one or both of c to 1d are operating, they are opened and the others are closed. Here, if the load of the cooling device is small, such as in winter or at night, the refrigerator performs the capacity control operation, and continues the operation with, for example, the two compressors 1a to 1b. In that case, the two compressors 1a-1b
Of the refrigerant discharged from the oil separator 2b flows into the oil separator 2b and may fall asleep as liquid refrigerant, but since the compressors 1c to 1d are stopped, the oil circuit solenoid valve 20b is closed and the oil The refrigerant stored in the separator 2b does not flow into the oil tank 9.

Next, when the compressor is switched from two-unit operation to three-unit operation due to fluctuations in the cooling load, a large amount of oil is taken out of the compressor for starting the compressor 1c, and the operation of the oil supply unit 10c is performed. Thus, the oil stored in the oil tank 9 is supplied to the compressor 1c.

The compressor 1 is operated by the action of the oil circuit solenoid valve 20b.
The refrigerant supplied to c does not contain refrigerant, and the concentration of oil in the compressor 1c does not decrease. This makes it possible to supply a highly reliable refrigerant circuit device that is less likely to cause poor lubrication in the compressor.

According to the first embodiment of the present invention, the first and second and the third and fourth connected in parallel.
Compressors 1a to 1d, the first and second compressors 1
a first oil separator 2a for receiving the refrigerant discharged from the first and second compressors 1a and 1b for separating oil from the refrigerant discharged from the first and second compressors 1a and 1b, and the third and fourth compressors 1c and 1d
To separate oil from refrigerant discharged from the third and fourth
A second oil separator 2b for receiving refrigerant discharged from the compressors 1c and 1d, an oil tank 9 for storing oil separated by the first and second oil separators 2a and 2b, and the compressors 1a to 1d. An oil supply device 10 for controlling oil supply from the oil tank to the compressors 1a to 1d according to the height of the oil level 1d
a to 10d, the third and fourth compressors 1c and 1c are stopped when at least one of the first and second compressors 1a and 1b is in operation.
d corresponding to the second oil separator 2b and the oil tank 9
Oil circuit solenoid valve that closes a circuit between the second oil separator 2b and the oil tank 9 when at least one of the third and fourth compressors 1c and 1d operates. A first oil circuit opening / closing means comprising 20b;
In addition, the first and second compressors that are stopped when at least one of the third and fourth compressors 1c and 1d are operating.
First oil separator 2a corresponding to the compressors 1a and 1b of FIG.
And a circuit between the first oil separator 2a and the oil tank 9 when at least one of the first and second compressors 1a and 1b is operated. Since the second oil circuit opening / closing means including the oil circuit solenoid valve 20a is provided, the circuit between the oil separator and the oil tank is appropriately opened / closed by the oil circuit opening / closing means, thereby being separated by the oil separator. Thus, it is possible to obtain a refrigerant circuit facility that can accurately prevent the refrigerant from being mixed into the oil tank that stores the accumulated oil.

Embodiment 2 FIG. FIG. 2 is a configuration diagram showing a refrigerant circuit facility according to Embodiment 2 of the present invention,
Are all the same as in the first embodiment. Reference numerals 30a to 30b indicate heaters attached to the oil separators 2a to 2b.

Next, the refrigerant circuit equipment in this embodiment will be described. First, regarding the operation / stop of the heater, the heater 30a stops when one or both of the compressors 1a and 1b are operating, and operates the other. Similarly, the heaters 30b are also connected to the compressors 1c to 1d.
Stop when one or both of them are operating, and operate the other. Here, if the load of the cooling device is small, such as in winter or at night, the refrigerator performs the capacity control operation,
For example, the operation with the two compressors 1a and 1b is continued. In this case, a part of the refrigerant discharged from the two operating compressors 1a to 1b flows into the oil separator 2b and may fall as a liquid refrigerant, but the compressors 1c to 1d are stopped. Since the heater 30b is operating, the oil separator 2
The refrigerant in b rises in temperature and evaporates, and does not fall asleep.

Next, when the compressor is switched from two-unit operation to three-unit operation due to the fluctuation of the cooling load, a large amount of oil is taken out of the compressor for starting the compressor 1c, and the operation of the oil supply unit 10c is performed. Thus, the oil stored in the oil tank 9 is supplied to the compressor 1c.

The heater 30 attached to the oil separator 2b
The refrigerant does not stagnate in the oil supplied to the compressor 1c by the action of b, and the concentration of the oil in the compressor 1c does not decrease. Thereby, poor lubrication of the compressor can be reduced, and a highly reliable refrigerant circuit device can be supplied.

According to the second embodiment of the present invention, the first and second and the third and fourth connected in parallel.
Compressors 1a to 1d, the first and second compressors 1
a first oil separator 2a for receiving the refrigerant discharged from the first and second compressors 1a and 1b for separating oil from the refrigerant discharged from the first and second compressors 1a and 1b, and the third and fourth compressors 1c and 1d
To separate oil from refrigerant discharged from the third and fourth
A second oil separator 2b for receiving the refrigerant discharged from the compressors 1c and 1d, an oil tank 9 for storing the oil separated by the first and second oil separators 2a and 2b, and the compressors 1a to 1d. An oil supply device 10 for controlling oil supply from the oil tank to the compressors 1a to 1d according to the height of the oil level 1d
a to 10d, the third and fourth compressors 1c, 1 which are stopped when at least one of the first and second compressors 1a, 1b is in operation.
d. a first heater means 3 for heating the second oil separator 2b connected to the first and second compressors 1c and 1d and stopping heating when at least one of the third and fourth compressors 1c and 1d is operated.
0b, and the third and fourth compressors 1c, 1c,
1d, heats the first oil separator 2a connected to the first and second compressors 1a and 1b, which are stopped during the operation of at least one of the first and second compressors. Since the second heater means 30b for stopping the heating when at least one of the machines 1a and 1b is operated is provided, by appropriately heating the oil separator, the oil separator stores the oil separated by the oil separator. Refrigerant circuit equipment capable of accurately preventing mixing of the refrigerant.

The embodiment according to the present invention is configured as described above, and has the following effects.

According to the embodiment of the present invention, the oil circuit solenoid valve is provided in the circuit between the oil separator and the oil tank. Even if the liquid refrigerant stagnates in the oil separator, the liquid refrigerant remains in the oil separator. Since it does not move to the oil tank and falls asleep, it is possible to prevent the concentration of the oil supplied from the oil tank, that is, the oil concentration in the compressor from lowering, and to provide a highly reliable refrigerant circuit equipment.

Further, according to the embodiment of the present invention, since the oil separator is provided with the heater, the stagnation of the liquid refrigerant into the oil separator can be prevented, whereby the oil concentration in the oil tank and the compressor can be reduced. It is possible to provide a highly reliable refrigerant circuit equipment capable of suppressing the decrease.

[0029]

According to the first aspect of the present invention, the circuit of the oil separator and the oil tank is appropriately opened and closed by the oil circuit opening and closing means, so that the refrigerant is transferred to the oil tank storing the oil separated by the oil separator. It is possible to obtain the refrigerant circuit equipment capable of accurately preventing the mixture.

According to the second aspect of the present invention, the oil separator corresponding to the compressor stopped operating when at least one of the compressors is in operation and the oil separator opening / closing means for closing the oil tank circuit. By properly opening and closing the circuit of the oil tank and the oil tank, it is possible to obtain a refrigerant circuit facility capable of appropriately preventing the refrigerant from being mixed into the oil tank storing the oil separated by the oil separator.

According to the third invention, the operation of the oil separator and the oil tank corresponding to the third and fourth compressors that are stopped when at least one of the first and second compressors is in operation. A first oil circuit opening / closing means for closing the circuit and opening when at least one of the third and fourth compressors is operated, and operating at least one of the third and fourth compressors; At the same time, the circuits of the oil separator and the oil tank corresponding to the first and second compressors whose operation is stopped are closed, and at least one of the first and second compressors is closed.
By providing the second oil circuit opening / closing means which is opened when the table is operated, the circuit between the oil separator and the oil tank is appropriately opened / closed to prevent the refrigerant from being mixed into the oil tank storing the oil separated by the oil separator. Refrigerant circuit equipment that can be prevented accurately can be obtained.

According to the fourth aspect of the present invention, the circuit between the oil separator and the oil tank is appropriately opened and closed by the oil circuit opening and closing means comprising an electromagnetic valve, so that the oil separated by the oil separator is stored in the oil tank. It is possible to obtain a refrigerant circuit facility that can appropriately prevent the refrigerant from being mixed.

According to the fifth aspect of the present invention, the refrigerant circuit equipment can appropriately prevent the refrigerant from being mixed into the oil tank storing the oil separated by the oil separator by appropriately heating the oil separator by the heater means. Can be obtained.

According to the sixth aspect of the present invention, the oil separator is appropriately heated by the heater means for heating and operating the oil separator corresponding to the compressor whose operation is stopped when at least one of the compressors is operating. Accordingly, it is possible to obtain the refrigerant circuit equipment capable of accurately preventing the refrigerant from being mixed into the oil tank storing the oil separated by the oil separator.

According to the seventh aspect, the second oil separator corresponding to the third and fourth compressors that are stopped when at least one of the first and second compressors is operating is provided. A first heater for heating and stopping heating when at least one of the third and fourth compressors is operated, and at least one of the third and fourth compressors;
Heating the first oil separators corresponding to the first and second compressors that have stopped operating during the operation of the table;
By providing a second heater means for stopping heating when at least one of the first and second compressors is operated, the oil separated by the oil separator is stored by appropriately heating the oil separator. Refrigerant circuit equipment capable of accurately preventing the refrigerant from being mixed into the oil tank can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing refrigerant circuit equipment according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram illustrating refrigerant circuit equipment according to Embodiment 2 of the present invention.

FIG. 3 is a configuration diagram showing a refrigerant circuit facility according to a conventional facility.

[Explanation of symbols]

1a-1d compressor, 2a-2b oil separator, 3a-3
d condenser, 4 receiver, 5a-5d expansion valve, 6a-
6d oil cooler pipe, 7a-7b accumulator, 8a-8b communication pipe, 9 oil tank, 10a-
10d oil supply, 20a-20b oil circuit solenoid valve, 3
0a-30b heater.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Isao Sakagami 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (7)

[Claims] A plurality of compressors connected in parallel, an oil separator for separating oil from refrigerant discharged from the compressor, and an oil tank for storing the oil separated by the oil separator; In a refrigerant circuit facility having an oil supply unit that controls oil supply from the oil tank to the compressor according to the height of the oil level of the compressor, the oil separator and the oil separator according to operation / stop of the compressor. Refrigerant circuit equipment provided with oil circuit opening / closing means for opening / closing a circuit between the oil tanks. A plurality of compressors connected in parallel; a plurality of oil separators for separating oil from refrigerant discharged from the compressor; and an oil tank for storing the oil separated by the oil separator. In addition, in a refrigerant circuit facility having an oil supply device that controls oil supply from the oil tank to the compressor according to the height of the oil level of the compressor, the operation is performed when at least one of the compressors is operated. Refrigerant circuit equipment provided with oil circuit opening / closing means for closing a circuit between an oil separator corresponding to a stopped compressor and the oil tank. 3. First and second and third and fourth compressors connected in parallel, the first and second compressors for separating oil from refrigerant discharged from the first and second compressors. A first oil separator that receives refrigerant discharged from the third compressor, and a second oil separator that receives refrigerant discharged from the third and fourth compressors to separate oil from refrigerant discharged from the third and fourth compressors.
Oil separator, an oil tank for storing oil separated by the first and second oil separators, and oil supply from the oil tank to the compressor according to the height of the oil level of the compressor In the refrigerant circuit equipment having an oil supply controlling the
Closing a circuit between the second oil separator and the oil tank corresponding to the third and fourth compressors that are stopped when at least one of the first and second compressors is operating. A first oil circuit opening / closing means for opening a circuit between the second oil separator and the oil tank when at least one of the third and fourth compressors is operated; And closing a circuit between the first oil separator and the oil tank corresponding to the first and second compressors that have stopped operating during operation of at least one of the fourth compressors, At least one of the first and second compressors
Refrigerant circuit equipment comprising a second oil circuit opening / closing means for opening a circuit between the first oil separator and the oil tank during operation of the table. 4. The refrigerant circuit equipment according to claim 1, wherein a solenoid valve is used as said oil circuit opening / closing means. 5. A compressor comprising: a plurality of compressors connected in parallel; an oil separator for separating oil from refrigerant discharged from the compressor; and an oil tank for storing oil separated by the oil separator. In a refrigerant circuit facility having an oil supply device that controls oil supply from the oil tank to the compressor according to the height of the oil level of the compressor, a heater that operates / stops according to operation / stop of the compressor Refrigerant circuit equipment characterized in that means are provided in the oil separator. 6. A plurality of compressors connected in parallel, a plurality of oil separators for separating oil from refrigerant discharged from the compressor, and an oil tank for storing the oil separated by the oil separator. In addition, in a refrigerant circuit facility having an oil supply device that controls oil supply from the oil tank to the compressor according to the height of the oil level of the compressor, the operation is performed when at least one of the compressors is operated. Refrigerant circuit equipment provided with heater means for heating and operating an oil separator corresponding to a stopped compressor. 7. The first and second and third and fourth compressors connected in parallel, the first and second compressors for separating oil from refrigerant discharged from the first and second compressors. A first oil separator that receives refrigerant discharged from the third compressor, and a second oil separator that receives refrigerant discharged from the third and fourth compressors to separate oil from refrigerant discharged from the third and fourth compressors.
Oil separator, an oil tank for storing oil separated by the first and second oil separators, and oil supply from the oil tank to the compressor according to the height of the oil level of the compressor In the refrigerant circuit equipment having an oil supply controlling the
While operating at least one of the first and second compressors, the second oil separators corresponding to the third and fourth compressors whose operation is stopped are heated, and the third and fourth oil separators are operated. A first heater means for stopping the heating when at least one of the four compressors is operated, and a first heater means for stopping the operation when at least one of the third and fourth compressors is operated. A second heater means for heating the first oil separator corresponding to the second compressor and stopping heating when at least one of the first and second compressors is operated. Characteristic refrigerant circuit equipment.