JPH0544678A - Sealed type rotary compressor - Google Patents

Abstract

PURPOSE:To constitute a compressor which can be applied to a water system for cooling and warming and carries out the low stage compressor single operation and the high stage compressor single operation which are advantageous in case of low faculty, parallel operation which is advantageous in case of high faculty, and twostage compression operation which is advantageous in the high compression ratio operation, and possesses the wide variable width of faculty, and permits the disposal of the high pressure compression ratio. CONSTITUTION:The low and high stage side compression mechanisms 5 and 6 and the low and high stage side motors 3 and 4 for driving both the compression mechanisms 5 and 6 are installed in a sealed shell 2, and at least the high stage side compression mechanism 6 is installed at the position on the opposite side to the low stage side compression mechanism 5 for the low stage side motor 3. A low stage suction pipe 7, high stage suction pipe 9, and a high stage discharge pipe 10 are opened outside the sealed shell 2, and a low stage discharge pipe 8 is opened in the sealed shell 2. Further, the inside of the sealed shell 2 and the outside of the sealed shell 2 are allowed to communicate by arranging a pipe A11 at the position on the opposite side to the low stage side compression mechanism 5 for the low stage side motor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic rotary compressor for compressing a circulating refrigerant such as a refrigerating device by a low-stage compression mechanism and a high-stage compression mechanism.

[0002]

2. Description of the Related Art Conventionally, when a ratio (compression ratio) between the evaporation pressure and the condensation pressure of a refrigeration cycle is large as in a low temperature refrigeration system or a high temperature heat pump, the discharge temperature of the compressor is prevented from rising and the compressor efficiency is improved. In order to improve the above, a two-stage compression device in which two conventional one-stage compressors are provided in series is used. In this case, the discharge gas of the low-stage compressor is directly or indirectly heat-exchanged with a high-pressure liquid refrigerant or an intermediate-pressure two-phase refrigerant to be cooled, and then sucked into the high-stage compressor, where the high pressure Is compressed and discharged. By so doing, the intake gas temperature of the high-stage compressor is lowered and its discharge temperature is prevented from rising. Also, by appropriately setting the compression ratios of the low-stage side and high-stage side compressors, it is possible to operate under conditions with good compressor efficiency in each stage, and overall improve refrigeration cycle efficiency. is there.

A device has also been devised which switches between single-stage parallel operation or single-stage operation and two-stage operation by using two compressors (for example, Japanese Patent Laid-Open No. 63-87556), and by opening and closing a valve provided in a pipe. The capacity can be widely varied from one low-capacity operation to two high-capacity operations, and high-efficiency operation can be performed by the two-stage operation when the compression ratio is high.

Further, a device for performing two-stage operation with one compressor has been devised (for example, Japanese Patent Publication No. 53-9410).
A single motor and low-stage and high-stage compression mechanisms are coaxially installed in a single sealed shell, and the gas compressed in the low stage is cooled once and then compressed to high pressure in the high stage to achieve high efficiency. It is a stage compression.

[0005]

However, in the conventional example in which two compressors are used for two-stage compression or parallel operation, the lubricating oil of the compressor is not uniformly held on the low-stage side and the high-stage side. However, there is a need for an oil separator for both high and low stages because of the deviation of the oil, or even if they are used, it is not possible to completely eliminate the deviation of the oil. There was a risk that seizure of the compressor might occur due to the decrease.

In addition, since one compressor is used for two-stage compression and operates with one motor, when it is used for a high temperature heat pump, for example, in the case of high compression ratio operation in which the load side has a high temperature. Is suitable, but when high capacity is required at a relatively low compression ratio, such as at the start of operation, the motor speed was varied to increase the heating capacity, so the upper limit is the motor speed. Being constrained, it was not possible to expect a significant increase in capacity, and it took time to get up.

The present invention realizes switching between one-stage (single-stage) compression and two-stage compression with a simple structure, has a wide variable capacity range from low capacity to high capacity, and only requires one oil separator. It is an object of the present invention to provide a hermetic rotary compressor that can be operated safely without oil deviation.

[0008]

A hermetic rotary compressor according to the present invention comprises a low-stage compression mechanism and a high-stage compression mechanism in a hermetic shell, and a low-stage motor and a high-stage motor for driving them. At least the high-stage compression mechanism is provided at a position opposite to the low-stage compression mechanism with respect to the low-stage motor, and includes a low-stage suction pipe, a high-stage suction pipe, and a high-stage discharge pipe, respectively. The outside of the closed shell is opened, the low-stage discharge pipe is opened into the closed shell, and the pipe A is provided at a position opposite to the low-stage side compression mechanism with respect to the low-stage side motor. The inside is communicated with the outside of the closed shell.

[0009]

With the above-described structure, the present invention is advantageous in simple operation, low-stage compressor independent operation advantageous for low capacity, high-stage compressor independent operation, parallel operation advantageous for high capacity, and further advantageous for high compression ratio operation. It is possible to realize a compressor configuration capable of performing a wide two-stage compression operation, having a wide range of variable capacity, and capable of supporting a high compression ratio.

Further, at the time of operation at a high compression ratio, the low-stage discharge gas at an intermediate pressure can be discharged into the closed shell, so that the motor at the high-stage side can be sufficiently cooled and safe operation can be performed.

Also, since the closed shell is one, the oil level can be supplied to any compression mechanism without deviation and the discharge gas can be supplied to the high pressure gas pipe during any operation. It is possible to pass two oil separators and return the separated oil to the low pressure gas pipe,
With a simple structure, the oil level inside the closed shell is stable and safe operation is possible.

[0012]

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

FIG. 1 shows one embodiment of the present invention, showing a case where a refrigerating cycle is constituted by using the hermetic rotary compressor of the present invention. In FIG. 1, 1 is a hermetic rotary compressor, 2 is a substantially cylindrical hermetic shell, 3 is a low-stage motor, 4 is a high-stage motor, 5 is a low-stage compression mechanism, 6
Is a high-stage side compression mechanism, and in this embodiment, the low-stage side motor 3
And the high-stage side motor 4 are in a positional relationship facing the inside of each compression mechanism. A low-stage suction pipe 7 is open to the outside of the closed shell 2. Reference numeral 8 denotes a low-stage discharge pipe which opens into the closed shell 2. Reference numeral 9 is a high-stage suction pipe, and 10 is a high-stage discharge pipe, which are opened to the outside of the closed shell 2.

Reference numeral 11 denotes a pipe A which communicates the inside and outside of the closed shell 2 and is located here on the end face side of the closed shell 2 with respect to the high-stage compression mechanism 6. Reference numeral 12 is a pipe B that communicates the inside and outside of the closed shell. Here, the low-stage motor 3
And the high-stage side motor 4 are located between them. Reference numeral 13 is a low-pressure gas pipe, which is branched and connected to the low-stage suction pipe 7 on one side and connected to the high-stage suction pipe 9 via the switching valve a14 on the other side. Further, the pipe A11 is branched, and one of them is the intercooler 1
5 to the switching valve a14, and the other one is a check valve 1
It is connected to the high pressure gas pipe 17 via 6.

Reference numeral 18 denotes a switching valve b, which can switch and connect the high-stage discharge pipe 10, the pipe B12 and the high pressure gas pipe 17. Reference numeral 19 is an oil separator, which is a high-pressure gas pipe 1
7, the oil separated here returns to the low pressure gas pipe 13 through the pipe 20 due to the pressure difference.

Reference numeral 21 is a condenser, 22 is a throttling device, and 23 is an evaporator. The discharge gas discharged from the oil separator 19 constitutes a refrigeration cycle through these, returns to the low-pressure gas pipe 13, and is sucked again. It

The operation method in each mode in such a configuration will be described.

First, when the ratio of the pressure of the condenser 21 and the pressure of the evaporator 23 is large and the compression ratio is high, the switching valve is operated as shown in the figure by the circuit shown in FIG. Perform compression operation.

That is, in this case, the suction gas of the low-pressure gas pipe 13 flows in the order of the low-stage suction pipe 7 → the low-stage side compression mechanism 5 → the low-stage discharge pipe 8 to be compressed at a low pressure to enter the closed shell 2. After being discharged and cooling the low-stage side motor 3 and the high-stage side motor 4, after being discharged from the pipe A11 and exchanged heat with an external fluid or an internal refrigerant in the intercooler 15 (not shown), It is sucked from the high-stage suction pipe 9 through the switching valve a14 and compressed to a high pressure by the high-stage side compression mechanism 6.

The gas compressed to a high pressure is supplied to the high-stage discharge pipe 10
Is further discharged, flows into the high-pressure gas pipe 17 through the switching valve b18, further separates oil in the oil separator 19, and the refrigerant gas passes through the condenser 21, the expansion device 22, and the evaporator 23, and again into the low-pressure gas pipe. Return to 13. On the other hand, the separated oil returns to the low pressure gas pipe 13 through the pipe 20 and is sucked again.

As described above, when the compression ratio is high, the two-stage compression circuit greatly improves the adiabatic efficiency of the low-stage compression mechanism and the high-stage compression mechanism as compared with the case where the compression mechanism is performed by one stage. Cycle efficiency is improved. Further, since the low-stage motor 3 and the high-stage motor 4 can be cooled by the low-stage discharge gas having a relatively low intermediate pressure, the motor is not overheated even at a high compression ratio. Further, since the oil can be reliably returned to the low pressure gas pipe 13 by only one oil separator 19 provided in the high pressure gas pipe 17, the amount of oil in the closed shell 2 is secured, and the compressor structure with high safety is provided. It will be.

Next, when the compression ratio is not so large as when starting the refrigerating cycle and the capacity is rather high, parallel operation is performed and the switching valve is operated by the circuit as shown in FIG. Operate as shown.

That is, in this case, the low-pressure gas pipe 13
Of the intake gas is branched, and the low-stage side flows in the order of the low-stage intake pipe 7 → the low-stage side compression mechanism 5 → the low-stage discharge pipe 8 and is discharged into the closed shell 2. The low-stage side motor 3 and the high-stage side After cooling the motor 4, it is discharged from the pipe A11 and flows through the check valve 16 into the high pressure gas pipe 17.

On the other hand, on the high-stage side, the suction gas branched by the low-pressure gas pipe 13 is sucked from the high-stage suction pipe 9 through the switching valve a14, compressed by the high-stage compression mechanism 6, and discharged by the high-stage discharge pipe 10.
Is further discharged, merges with the discharge gas on the lower stage side through the switching valve b18, and flows into the oil separator 19. Where the oil is separated,
The refrigerant gas flows in the order of the condenser 21, the expansion device 22, and the evaporator 23 to form a cycle, and then returns to the low-pressure gas pipe 13 again. On the other hand, the separated oil returns to the low-pressure gas pipe 13 through the pipe 20, so that the oil level in the closed shell 2 is ensured and the compressor structure has high safety.

As described above, when a relatively high compression ratio and a large amount of capacity are required, the capacity is sufficiently secured and the start-up is improved by operating the low-stage side and the high-stage side in parallel in a single-stage compression operation. To do. Further, the capacity can be further improved by increasing the rotation speed of the motor by using, for example, an inverter. Further, in this case, the case where both the low-stage motor 3 and the high-stage motor 4 are cooled by the low-stage discharge gas discharged into the closed shell 2 has been shown.
Is rotated 90 degrees to the left and the high-stage discharge gas is caused to flow into the closed shell 2 through the pipe B12.
Can also be cooled by both low-stage and high-stage discharge gas.

Next, in the case where the load is small and the capacity is not required so much, for example, by operating the switching valve in the circuit as shown in FIG. 4 as shown in the figure, low-stage independent operation can be performed, and By operating the switching valve as shown in the figure with the circuit as shown in FIG. 5, high-stage isolated operation can be performed.

Explaining from the low-stage independent operation of FIG. 4, the suction gas of the low-pressure gas pipe 13 flows in the order of the low-stage suction pipe 7 → the low-stage side compression mechanism 5 → the low-stage discharge pipe 8 to be discharged into the closed shell 2. After cooling the low-stage motor 3, it is discharged from the pipe A11, flows through the check valve 16 into the high-pressure gas pipe 17, and then flows into the oil separator 19. Here, oil is separated, and the refrigerant gas flows in the order of the condenser 21, the expansion device 22, and the evaporator 23 to form a cycle, and then returns to the low-pressure gas pipe 13 again. On the other hand, the separated oil returns to the low pressure gas pipe 13 through the pipe 20. In this case, since the high-stage side is not operating and the high-stage suction pipe 9 is at a low pressure, the accumulation of the refrigerant does not occur.

Next, the high-stage isolated operation of FIG. 5 will be described.
The suction gas of the low-pressure gas pipe 13 flows in the order of the switching valve a14 → high-stage suction pipe 9 → high-stage side compression mechanism 6 → high-stage discharge pipe 10, and further flows into the closed shell 2 through the switching valve b18 → pipe B12. .. After cooling the high-stage side motor 4 here, the high-stage motor 4 is discharged from the pipe A11, passed through the check valve 16, and passed through the high-pressure gas pipe 17
→ Flows into the oil separator 19. Here, the oil is separated, and the refrigerant gas flows in the order of the condenser 21, the expansion device 22, and the evaporator 23 to form a cycle, and then returns to the low pressure gas pipe 13 again. On the other hand, the separated oil returns to the low pressure gas pipe 13 through the pipe 20. In this case, the low-stage side is not operating and the low-stage suction pipe 7 is at a low pressure, so that the accumulation of the refrigerant does not occur. Further, the oil is separated and returns to the low-pressure gas pipe 13 in both the low-stage operation and the high-stage operation, so that the oil level in the closed shell 2 is secured.

As described above, when a large amount of capacity is not required, the low-stage side and the high-stage side are switched to operate independently, so that even a small capacity can be operated with high efficiency corresponding to the capacity of each compression mechanism. It is obvious that it is possible to adjust the capacity better by combining it with the inverter, and it is also possible to operate the lower stage in parallel to the operation only on the higher stage side, for example. Needless to say.

[0030]

As is apparent from the above description, the hermetic rotary compressor of the present invention includes a low-stage compression mechanism and a high-stage compression mechanism in a hermetic shell, and a low-stage motor for driving each of them. A high-stage side motor, at least the high-stage side compression mechanism is provided at a position opposite to the low-stage side compression mechanism with respect to the low-stage side motor, and a low-stage suction pipe, a high-stage suction pipe, and a high-stage suction pipe are provided. The discharge pipes are opened outside the closed shell, the low-stage discharge pipes are opened inside the closed shell, and the pipe A is provided at a position opposite to the low-stage compression mechanism with respect to the low-stage motor. Since the inside of the closed shell and the outside of the closed shell are communicated with each other, a simple operation makes it possible to operate the low-stage compressor alone, which is advantageous when the capacity is low, a high-stage compressor alone operation, and the parallel operation which is advantageous when the capacity is high. It is possible to perform an advantageous two-stage compression operation during compression ratio operation. Wide variable width, it is possible to realize a compressor structure which can accommodate up to a high compression ratio.

Further, at the time of high compression ratio operation, the intermediate pressure low-stage discharge gas can be discharged into the closed shell, so that the motor at the high-stage side is sufficiently cooled and safe operation can be performed.

Since only one closed shell is used, the oil surface is not offset and the oil can be supplied to any compression mechanism without excess or deficiency. Further, the discharge gas is provided in the high pressure gas pipe during any operation. Since it passes through two oil separators and returns the separated oil to the suction gas pipe, the oil level in the closed shell is stable with a simple structure, and safe operation is possible. It is effective.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a hermetic rotary compressor according to an embodiment of the present invention and a refrigeration cycle using the same.

FIG. 2 is a flow chart of refrigerant and oil in a hermetic rotary compressor of one embodiment of the present invention and a two-stage compression operation using the same.

FIG. 3 is a flow chart of a hermetic rotary compressor according to an embodiment of the present invention and refrigerant and oil in parallel operation using the hermetic rotary compressor.

FIG. 4 is a flow chart of a hermetic rotary compressor of one embodiment of the present invention and a refrigerant and oil in low-stage independent operation using the same.

FIG. 5 is a flow chart of a hermetic rotary compressor of one embodiment of the present invention and a refrigerant and oil in a high-stage independent operation using the same.

[Explanation of symbols]

 1 Hermetic rotary compressor 2 Hermetic shell 3 Low-stage motor 4 High-stage motor 5 Low-stage compression mechanism 6 High-stage compression mechanism 7 Low-stage suction pipe 8 Low-stage discharge pipe 9 High-stage suction pipe 10 High-stage discharge Pipe 11 Pipe A 12 Pipe B 13 Low pressure gas pipe 14 Switching valve a 15 Intercooler 16 Check valve 17 High pressure gas pipe 18 Switching valve b 19 Oil separator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Ebi 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A low-stage side compression mechanism and a high-stage side compression mechanism, and a low-stage side motor and a high-stage side motor for driving the low-stage side compression mechanism and the high-stage side compression mechanism are provided in a hermetic shell of a compressor, and at least the high-stage side compression mechanism. Is provided at a position opposite to the low-stage side compression mechanism with respect to the low-stage side motor, and includes a low-stage suction pipe of the low-stage side compression mechanism, a high-stage suction pipe of the high-stage side compression mechanism, and a high-stage suction pipe. Stage discharge pipes are respectively opened to the outside of the closed shell, the low stage discharge pipes of the low stage side compression mechanism are opened to inside the closed shell,
Further, the pipe A is provided at a position opposite to the low-stage side compression mechanism with respect to the low-stage side motor, and the inside of the hermetic shell and the outside of the hermetic shell communicate with each other. Type rotary compressor. 2. A low-stage suction pipe is connected to a low-pressure gas pipe, the low-pressure gas pipe is branched to be connected to the high-stage suction pipe via a switching valve a, and the pipe A is branched to one side. Is connected to the high pressure gas pipe, and the other is connected to the switching valve a,
The high-stage suction pipe can be switched between the low-pressure gas pipe and the pipe A, and the pipe B can be connected to the closed shell at a position opposite to the pipe A with respect to the high-stage motor. The high-stage discharge pipe and the pipe B thereof are connected via a switching valve b, and the high-stage discharge pipe can be switched and connected to the pipe B and the high-pressure gas pipe. The hermetic rotary compressor according to claim 1, which is characterized in that. 3. The hermetic rotary compressor according to claim 2, wherein a check valve is provided midway between the pipe A and the high-pressure gas pipe. 4. The hermetic rotary compressor according to claim 2, wherein the high pressure gas pipe is provided with an oil separator, and the low pressure gas pipe is provided with a circuit for returning oil.