JPH07167513A - Refrigeration equipment - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a refrigerating machine equipped with a twin scroll compressor, which is capable of reducing the fluctuation range of the discharge gas temperature of the compressor. [Structure] The capillary tubes 8a and 8b serve as a first pressure reducer for reducing the pressure of the high-pressure liquid refrigerant discharged from the condenser 2 and reducing the flow rate thereof. Further, the capillary tube 10 is commonly connected to the upstream sides of the capillary tubes 8a and 8b, and serves as a second pressure reducer that reduces the pressure of the high pressure liquid refrigerant discharged from the condenser 2 and reduces its flow rate. And
The liquid refrigerant inlet pipe provided with the solenoid valve 6 is connected to the solenoid valve 9
And are provided in parallel with the flow path of the capillary tube 10. With these, the flow rate of the high-pressure liquid refrigerant discharged from the condenser 2 is controlled and sent to the through holes 1ca and 1cb, respectively. [Effect] The fluctuation range of the discharge gas temperature of the compressor can be reduced with a small number of components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus equipped with a twin scroll compressor, and more particularly, to controlling a temperature of discharge gas of the compressor, a liquid is provided at a portion of the compressor at an intermediate pressure. The present invention relates to a refrigerating device that introduces a refrigerant (hereinafter referred to as “liquid injection”).

[0002]

2. Description of the Related Art As a conventional refrigeration system as described above,
There is a refrigeration apparatus described in Japanese Patent Application No. 3-254983. In this conventional refrigeration system, a scroll wrap and a twin scroll compressor having two pairs of electric motors for driving the scroll wrap are installed in one chamber and are connected to a condenser, a pressure reducer, and an evaporator to form a refrigerant circuit. And each of the scroll wraps has a through hole in the compression chamber, which is an intermediate pressure between the suction pressure and the discharge pressure, and the liquid refrigerant at the condenser outlet is introduced into the compression chamber through the through hole. It is a thing. Further, in this conventional refrigeration system, the check valve is provided in the liquid refrigerant introduction pipe connected to each through hole to prevent the reverse flow of the refrigerant gas during the liquid injection in the single lung operation. Here, the single lung operation refers to operating only one of the two scroll compressors.

Further, as a conventional refrigerating apparatus, Japanese Patent Laid-Open No.
There is a refrigeration system described in Japanese Patent Laid-Open No. 172408. This conventional refrigeration system has an introduction pipe for introducing the liquid refrigerant used in liquid injection into each compression chamber,
Two sets of solenoid valves and pressure reducers connected in series are connected in parallel. As a result, the amount of liquid refrigerant in the introduction pipe is optimized and the number of times the solenoid valve is energized is reduced.

[0004]

However, in the refrigerating apparatus described in the above-mentioned Japanese Patent Application No. 3-254983, when controlling the flow rate of the liquid refrigerant in the liquid injection, there is no control but zero or total amount. This is not possible, and the fluctuation range of the discharge gas temperature of the compressor becomes large.

On the other hand, in the refrigerating apparatus described in Japanese Patent Application No. 3-340661, it is possible to control the flow rate of the liquid refrigerant in the liquid injection in several stages.
The fluctuation range of the discharge gas temperature of the compressor can be reduced. However, when this method is applied to a twin scroll compressor, four solenoid valves and four pressure reducers are required, which causes an increase in manufacturing cost and a decrease in product reliability as the number of parts increases. .

An object of the present invention is to provide a refrigerating machine equipped with a twin scroll compressor, which can reduce the fluctuation range of the discharge gas temperature of the compressor.

[0007]

The refrigerating apparatus of the present invention is
A twin scroll compressor with two pairs of scroll wraps and electric motors for driving the scroll wraps is installed in one chamber and is connected to a condenser, a pressure reducer, and an evaporator to form a refrigerant circuit. In the refrigerating apparatus in which the through holes are provided in the compression chambers that are at the intermediate pressure between the suction pressure and the discharge pressure in the wrap and the liquid refrigerant at the condenser outlet is introduced into the compression chambers through the through holes, First decompressors for decompressing and introducing the liquid refrigerant are connected to the holes, respectively, and a second decompressor is connected in common upstream of the two first decompressors, and valves are provided in parallel with the second decompressor. It is characterized in that a tube having is provided.

Further, in the refrigerating apparatus of the present invention, it is preferable to provide a check valve in series with each of the two first pressure reducers.

Further, the refrigerating apparatus of the present invention is preferably provided with a valve for opening and closing the flow of the liquid refrigerant in the second pressure reducer.

[0010]

In the refrigerating apparatus of the present invention, the liquid refrigerant is introduced through the through holes into the compression chamber where the gas in each scroll wrap has an intermediate pressure between the suction pressure and the discharge pressure, and liquid injection is performed. The flow path of the liquid refrigerant used for the liquid injection is such that the first pressure reducers for decompressing and introducing the liquid refrigerant are respectively connected to the through holes provided in the two compression chambers, respectively. A second pressure reducer is commonly connected to the upstream side of the, and a pipe having a valve is provided in parallel with the second pressure reducer.

During normal operation, the flow of the liquid refrigerant in the pipes provided in parallel with the second pressure reducer is shut off by the valve, so that the liquid refrigerant is divided into two stages by the second pressure reducer and the first pressure reducer. The pressure is reduced to suppress the flow rate of the liquid refrigerant and perform the liquid injection to prevent the temperature of the gas discharged from the compressor from being excessively lowered.

If the temperature of the gas discharged from the compressor is still higher than the predetermined temperature even after performing the above liquid injection, the liquid refrigerant is caused to flow through the pipe provided in parallel with the second pressure reducer. As a result, the liquid refrigerant flows by bypassing the second pressure reducer, the flow rate of the liquid refrigerant used for liquid injection is increased, and the temperature of the gas discharged from the compressor is further strongly reduced.

Further, in the refrigerating apparatus of the present invention, since the first decompressor is provided in each of the two compression chambers, the discharge gas temperature of the compressor can be controlled even during the single lung operation in which only one compressor is operated. The fluctuation range can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a refrigerating apparatus according to an embodiment of the present invention. In the refrigerating apparatus of this embodiment, scroll wraps 1aa and 1ab and electric motors 1ba and 1bb for a compressor, which are electric motors for driving the scroll wraps 1aa and 1ab, are provided in one chamber.
There are two twin scroll compressors (hereinafter referred to as “compressors”) 1. Further, in the refrigerating apparatus of this embodiment, the condenser 2, the liquid receiver 3, the expansion valve 4, which serves as a pressure reducer, and the evaporator 5 are connected to form a refrigerant circuit.

The condenser 2 cools the gaseous refrigerant discharged from the compressor 1 with water or air to condense it into a liquid. The liquid receiver 3 is a container that temporarily stores the refrigerant that has become liquid in the condenser 2. The expansion valve 4 serves as a decompressor that expands the high-temperature, high-pressure liquid refrigerant discharged from the liquid receiver 3 into a low-temperature, low-pressure refrigerant. The evaporator 5 evaporates the low-temperature, low-pressure refrigerant that has exited from the expansion valve 4 and uses the latent heat of evaporation to perform a refrigerating action.

Further, in the refrigerating apparatus of this embodiment, through holes 1ca and 1cb are provided in the compression chambers of the scroll wraps 1aa and 1ab, respectively, which have intermediate pressures between the suction pressure and the discharge pressure. The high-pressure liquid refrigerant discharged from the condenser 2 is introduced into the through hole 1ca by the liquid receiver 3, the electromagnetic valve 6, the electromagnetic valve 9, the capillary tube 10, the check valve 7a.
And it is introduced through the capillary tube 8a.
On the other hand, the high-pressure liquid refrigerant discharged from the condenser 2 is introduced into the through hole 1cb via the liquid receiver 3, the solenoid valve 6, the solenoid valve 9, the capillary tube 10, the check valve 7b, and the capillary tube 8b. There is.

Here, the capillary tubes 8a, 8b
Serves as a first pressure reducer that reduces the pressure of the high-pressure liquid refrigerant discharged from the condenser 2 to reduce the flow rate of the liquid refrigerant. Further, the capillary tube 10 is the capillary tube 8
The second pressure reducer is connected in common to the upstream side of a and 8b and reduces the pressure of the high pressure liquid refrigerant discharged from the condenser 2 to reduce the flow rate of the liquid refrigerant. The liquid refrigerant introduction pipe provided with the solenoid valve 6 is provided in parallel to the flow paths of the solenoid valve 9 and the capillary tube 10. By opening the solenoid valve 6, the solenoid valve 9 and the capillary tube 10 are connected. Bypass the liquid refrigerant.

FIG. 2 is a sectional view showing the structure and operation of the scroll wrap in the refrigerating apparatus of FIG. The scroll wrap of this embodiment has a suction port 21, which is an inlet for sucking gas, a fixed scroll 24, and an orbiting scroll 25.
The room is partitioned by and, and has a compression chamber 22 where the gas sucked from the suction port 21 is compressed, and a discharge port 23 which is a discharge port of the compressed gas.

FIG. 2A shows a state in which gas is absorbed from the suction port 21 provided outside the fixed scroll 24. After that, (B), (C), and
As shown in (D), the orbiting scroll 25 rotates to reduce the internal volume of the compression chamber 22, and the gas is compressed toward the center of the vortex with this reduction. As shown in FIG. 2D, the volume of the compression chamber 22 is minimized at the center of the scroll wrap, and the gas is compressed to the maximum and pushed out through the discharge port 23 at the center. And
The above-described movements from gas suction to compression and discharge are repeated.

Here, in the suction process 22a shown in FIG. 2B, the gas is sucked into the scroll. Also, the compression process 22b is where the gas in the scroll is compressed. Also, the discharge process 22c
Is where the gas in the scroll is exhaled.

Next, the operation of the main part of this embodiment will be described. Two compressor electric motors 1ba, 1 in the compressor 1
Each bb can be operated individually. That is,
It is possible to perform a single lung operation in which only one compressor electric motor is operated and a whole lung operation in which both compressor electric motors are operated. At the start of the operation of the refrigerating apparatus of this embodiment, the solenoid valves 6 and 9 are both closed, and the high pressure liquid refrigerant at the outlet of the condenser 2 is not supplied to the through holes 1ca and 1cb.

Then, when the temperature of the gas discharged from the compressor 1 exceeds a predetermined temperature during the operation of the refrigerating apparatus of this embodiment, the solenoid valve 9 is opened. The operation of opening the solenoid valve 9 may be synchronized with the start of operation of the compressor electric motors 1ba and 1bb. As a result, the high-pressure liquid refrigerant passes through the solenoid valve 9 and is separated into two by the capillary tube 10 and the capillary tube 8a or the capillary tube 8b.
It is decompressed in stages and flows into the through holes 1ca and 1cb, respectively.

As a result, the high-pressure liquid refrigerant cooled in the condenser 2 is supplied from the through holes 1ca, 1cb to the compression chambers of the scroll wraps 1aa, 1ab, so that the temperature rise of the gas discharged from the compressor 1 is suppressed. Therefore, the temperature of the discharged gas can be lowered.

If the temperature of the gas discharged from the compressor 1 still rises, the solenoid valve 6 is opened. As a result, the high-pressure liquid refrigerant bypasses the capillary tube 10 and flows, so that the high-pressure liquid refrigerant flows into the capillary tube 8.
The pressure is reduced only in one stage of a or the capillary tube 8b. Therefore, the flow rate of the high-pressure liquid refrigerant is increased, and the temperature of the discharge gas of the compressor 1 can be further strongly reduced. In this state,
The opening and closing of the solenoid valve 9 has almost no effect on the operation of this embodiment.

Next, the refrigerating apparatus of this embodiment and the above-mentioned conventional refrigerating apparatus will be compared. Applying the technique described in Japanese Patent Application No. 3-340661, which is a technique relating to a conventional refrigeration system, to a twin scroll compressor,
The function of controlling the flow rate of the high-pressure liquid refrigerant for lowering the temperature of the discharge gas of the compressor has substantially the same performance. Further, both the refrigerating apparatus of the present embodiment and the above-mentioned conventional technique can individually control the supply flow rate of the high-pressure liquid refrigerant for each of the two sets of compressors, and are excellent even during single lung operation. The flow rate of the high pressure liquid refrigerant can be controlled.

However, in the technique disclosed in the above-mentioned Japanese Patent Application No. 3-340661, a solenoid valve is provided in the path for introducing the high-pressure liquid refrigerant from the outlet of the condenser to the through hole opened in the compression chamber of the scroll wrap. It requires four and four capillary tubes. On the other hand, in the refrigerating apparatus of this embodiment, two electromagnetic valves and three capillary tubes can be used.

As described above, the refrigerating apparatus of this embodiment can individually control the supply flow rate of the high-pressure liquid refrigerant to each of the two sets of compressors, so that the high-pressure liquid refrigerant can be satisfactorily operated at high pressure even in one lung operation. Since the flow rate of the liquid refrigerant can be controlled, the temperature of the gas discharged from the compressor can be well controlled even during the single lung operation. Furthermore, the refrigerating apparatus of this embodiment is
It is possible to realize a refrigerating machine having the above-mentioned effects with fewer parts than the conventional refrigerating machine.

On the other hand, as a technique for reducing the number of parts in the route for introducing the high-pressure liquid refrigerant from the outlet of the condenser to the through hole opened in the compression chamber of the scroll wrap, there is a point at which the high-pressure liquid refrigerant branches into two sets of compression chambers in the route. A method may be considered in which two capillary tubes are connected in series upstream of (a point corresponding to the branch point α in FIG. 1). With this method, it is possible to control the flow rate of the high-pressure liquid refrigerant without any problem during whole lung operation. However, during single lung operation, the high-pressure liquid refrigerant flows into the through holes 1ca and 1cb at a flow rate about twice as high as that in whole lung operation, causing the temperature of the gas discharged from the compressor to drop too much, or This has a drawback that the temperature of the gas discharged from the compressor is greatly changed.

On the other hand, in the refrigerating apparatus of this embodiment, as shown in FIG.
Since the second-stage capillary tubes 8a and 8b are provided in the downstream path of the branch point α in, the flow rate of the high-pressure liquid refrigerant to the through holes 1ca and 1cb in the state where only the solenoid valve 9 is open. Is slightly higher in one lung operation than in whole lung operation, but the increase rate is about 20% to 30%.

As described above, in the refrigerating system in which two capillary tubes are connected in series upstream of the branch point α, the flow rate of the high-pressure liquid refrigerant is approximately doubled during the whole lung operation and the single lung operation. However, in the refrigerating apparatus of the present embodiment, the fluctuation can be suppressed to about 20% to 30%, and fine flow rate control of the high pressure liquid refrigerant can be performed. As a result, the refrigeration system of the present embodiment can reduce fluctuations in the temperature of the gas discharged from the compressor during both whole lung operation and single lung operation.

[0032]

As described above, according to the present invention, in a refrigerator equipped with a twin scroll compressor, a through hole is provided in each compression chamber in two pairs of scroll wraps, and these two through holes are provided. First decompressors for decompressing and introducing the liquid refrigerant are connected to each other, a second decompressor is commonly connected on the upstream side of the two first decompressors, and the liquid refrigerant is introduced in parallel to the second decompressor. Since the pipe is provided, the fluctuation range of the discharge gas temperature of the twin scroll compressor can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a refrigerating apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the structure and operation of a scroll wrap in the refrigerating apparatus of FIG.

[Explanation of symbols]

 1 compressor 1aa, 1ab scroll wrap 1ba, 1bb electric motor for compressor 1ca, 1cb through hole 2 condenser 3 liquid receiver 4 expansion valve 5 evaporator 6,9 solenoid valve 7a, 7b check valve 8a, 8b, 10 capillary tube

Claims (3)

[Claims] 1. A twin scroll compressor having two pairs of scroll wraps and electric motors for driving the scroll wraps is mounted in one chamber, and is connected to a condenser, a pressure reducer, and an evaporator to form a refrigerant circuit. Then, a through-hole is provided in each compression chamber that has an intermediate pressure between the suction pressure and the discharge pressure in each scroll wrap, and a refrigerating device that introduces the liquid refrigerant at the condenser outlet into the compression chamber through the through-hole. At
1st which decompresses and introduces the said liquid refrigerant into two said through-holes
A refrigerating apparatus characterized in that pressure reducers are connected to each other, a second pressure reducer is commonly connected upstream of the two first pressure reducers, and a pipe having a valve is provided in parallel with the second pressure reducer. . 2. The refrigerating apparatus according to claim 1, wherein 2
A refrigerating apparatus comprising a check valve provided in series with each of the two first pressure reducers. 3. The refrigeration apparatus according to claim 1, further comprising a valve that opens and closes a flow of the liquid refrigerant in the second pressure reducer.