JPH0972636A - Accumulator and air conditioner utilizing this accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve gas-liquid separation of refrigerant and restrict flowing- back of liquid to a compressor by a method wherein a connecting pipe to a second container is connected to a bottom part of a first container in an accumulator for a freezing cycle and then an oil returning pipe connected to a suction pipe for the compressor is connected to a bottom part of the second container. SOLUTION: Refrigerant of gas-liquid phases is fed from an inlet pipe 7 to a first container 8a of an accumulator, where gas and liquid are separated from each other. The separated liquid refrigerant falls from a falling pipe 10 into a second container 8B, and stored in the second container 8B. In turn, the separated gaseous refrigerant is passed through a suction pipe 9 and returned to a suction of the compressor 1. In addition, oil dissolved in the refrigerant is returned to a bottom part of the compressor 1 through an oil returning pipe 11 and an adjusting device 12. Further, liquid refrigerant containing separated oil flows down to the second lower container 8B through the dropping pipe 10 at the bottom part of the first container 8A and is stored there. Accordingly, it is possible to improve a gas-liquid separating efficiency of the refrigerant and also to avoid a returning of the liquid to the compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator device installed in a refrigeration cycle.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a refrigeration cycle equipped with an accumulator.

In FIG. 8, during cooling, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 enters the outdoor heat exchanger 4 through the discharge pipe 2 and the four-way valve 3. The refrigerant is cooled here by air sent by an outdoor fan (not shown), is condensed into a liquid refrigerant, is decompressed by the throttle 5, and then enters the indoor heat exchanger 6.

This liquid refrigerant exchanges heat with air sent here by an indoor fan (not shown) to cool it.
It itself is heated to become a gas refrigerant, and is returned from the suction pipe 9 to the compressor 1 via the four-way valve 3, the accumulator inlet pipe 7, and the accumulator 8. During heating, the four-way valve 3 is switched, the functions of the indoor heat exchanger 6 and the outdoor heat exchanger 4 are opposite to those in the case of cooling, and the indoor heat exchanger 6 condenses the refrigerant and the outdoor heat exchanger 4 To evaporate the refrigerant.

In the above refrigeration cycle, when the load on the evaporator side (the indoor heat exchanger 6 during cooling, the outdoor heat exchanger 4 during heating) decreases, the non-evaporated refrigerant, that is, the liquid refrigerant, becomes the four-way valve 3, It enters the accumulator 8 through the accumulator inlet pipe 7. In the same accumulator 8, gas-liquid is separated, the liquid is stored at the bottom of the container, and only gas is returned from the suction pipe 9 to the compressor 1.

Since the oil is dissolved in the liquid refrigerant, it is returned from the accumulator 8 together with the liquid refrigerant to the compressor 1 through the oil return pipe 11. In order to prevent the liquid refrigerant from returning too much to the oil return pipe 11 and to sufficiently return the oil to the compressor 1,
A diaphragm 12 is provided. As described above, the accumulator 8 performs the gas-liquid separation, stores the non-evaporated gas, that is, the liquid refrigerant, and plays the role of preventing the liquid back.

FIG. 9 shows a partial system diagram of a conventional example of the accumulator 8 and a refrigerant circuit around the accumulator 8. In FIG. 9, the accumulator 8 is a gas-liquid refrigerant mixture containing oil. It has two functions of separation and storage of the separated liquid 81.

[0008]

However, the above-mentioned conventional accumulator device has the following problems.

That is, in recent years, in air conditioners, the length of the connecting pipes inside and outside has become longer and the operating range has become wider, and the outside air temperature during cooling is -5 ° C to 50 ° C and during heating. The outside air temperature is in a wide range of -15 ° C to 25 ° C. Therefore, the refrigerant charge amount increases, and the required refrigerant amount changes greatly.

However, during the operation of the refrigeration cycle, the surplus refrigerant during the low load operation is the accumulator 8 mentioned above.
However, as described above, the accumulator 8 also has two functions of separating gas and liquid and storing the separated liquid. For this reason, the capacity of the accumulator 8 (that is, the size of the container) inevitably becomes large, and if the storage amount of the liquid (liquid in which oil is mixed with the refrigerant) increases, the gas-liquid separation efficiency decreases.

Further, the throttle 12 installed in the oil return pipe 11 always returns a constant oil-mixed liquid refrigerant to the compressor 1,
In particular, during a low load operation, an excessive amount of liquid refrigerant is returned to the compressor 1 through the oil return pipe 11, and the liquid back causes damage to the compressor 1.

The object of the present invention is to improve the gas-liquid separation efficiency of the oil-containing refrigerant flowing through the accumulator and to avoid the return of an excessive amount of the liquid refrigerant from the accumulator to the compressor, that is, the liquid back, It is to prevent the occurrence of damage to the compressor.

[0013]

Means for Solving the Problems The present invention solves the above problems, and the first means, which is the gist of the present invention, is to provide a refrigerant that is provided in a suction side pipe to a compressor and is returned to the compressor. An accumulator device for a refrigeration cycle having a gas-liquid separation action, wherein the accumulator is at least a first and a second.
And an inlet pipe of the suction side pipe and a suction pipe to the compressor are connected to the upper part of the first container, and the bottom part of the first container is connected to the second container. In the accumulator device, a connecting pipe is connected, and an oil return pipe connected to the compressor or a suction pipe to the compressor is connected to a bottom portion of the second container.

According to the above means, the oil-containing refrigerant introduced into the first container is gas-liquid separated into the non-evaporated refrigerant (gas-liquid two-phase refrigerant) in the first container and separated into gas and liquid. The liquid refrigerant is dropped from the bottom of the first container to the second container.

Further, only the gas refrigerant separated from the first container is returned to the compressor. In the second container, the separated liquid refrigerant is stored, and the oil dissolved in the liquid refrigerant is returned to the compressor together with the liquid refrigerant through the oil return pipe.

As described above, the gas-liquid separation is performed in the first container, the gas refrigerant is returned to the compressor, and the liquid refrigerant containing oil is sent to the second container and stored therein. The liquid separation efficiency is high, the occurrence of liquid back to the compressor is avoided, and the damage of the compressor due to this is prevented.

Further, in the above-mentioned means, the first container is arranged higher than the second container, and the liquid separated in the first container is dropped into the second container by gravity. Configure. According to this structure, the liquid refrigerant can be moved from the first container to the second container quickly and reliably.

In addition to the above, it is also a preferable means to connect the upper part of the first container and the upper part of the second container with a pressure equalizing pipe. According to such means, since the pressure difference between the first and second containers is eliminated, the liquid refrigerant can be easily moved from the first container to the second container.

Further, the accumulator device is a compressor,
It can also be installed in a suction side pipe between a compressor of a heat pump cycle including a four-way valve, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger and the four-way valve.

The second means of the present invention is an accumulator device for a refrigeration cycle, which is provided in a suction side pipe to the compressor and performs a gas-liquid separation action of a refrigerant returned to the compressor. At least the first and second 2
In addition to connecting the inlet pipe of the suction side pipe and the suction pipe to the compressor to the upper part of the first container,
A connecting pipe to the second container is connected to the bottom of the first container, and an oil return pipe connected to the compressor or a suction pipe to the compressor is connected to the bottom of the second container. Furthermore, the accumulator device is characterized in that the oil return pipe is provided with an electronic expansion valve for adjusting the opening of the pipe.

In addition to the above, a controller for outputting a control signal to the electronic expansion valve is provided, and the controller includes a detection signal such as a discharge pipe temperature of the compressor, a housing temperature, a discharge superheat degree, and a dilution degree of the refrigerating machine oil. Is input, and the controller is configured to control the opening degree of the electronic expansion valve based on these detection signals.

According to the above means, the temperature condition of the compressor and the degree of dilution of the frozen oil are detected, and the opening degree of the electronic expansion valve provided in the oil return line is controlled based on this detection signal. It is possible to accurately control the return flow rate of the liquid refrigerant containing oil after liquid separation to the compressor, maintain a higher gas-liquid separation efficiency, and cause liquid back to the compressor especially at low load. Certainly prevented.

Further, it is also a preferable concrete means to divide the second container into a plurality of parts, and to connect between the containers with a pressure equalizing pipe on the gas side and a liquid equalizing pipe on the liquid side. .

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a partial configuration diagram of a refrigeration cycle including an accumulator device according to a first embodiment of the present invention.

In FIG. 1, 1 is a compressor, 9 is a suction pipe for the refrigerant to the compressor 1, and 2 is a discharge pipe for the refrigerant from the compressor 1. Reference numeral 8A denotes a first container that constitutes one of the accumulators, and second container 8B that constitutes the other of the accumulators, and is a second container that is installed below the first container 8A.
The suction pipe 9 of the compressor 1 is connected to the upper part of the first container 8A, and the inlet pipe 7 of the suction side pipe from the four-way valve 3 (see FIG. 8) is connected. Reference numeral 10 is a drop pipe that connects the lower portion of the first container 8A and the second container 8B. Further, 11 is an oil return pipe that connects the bottom of the second container 8B and the compressor 1, and 12 is a throttle provided in the oil return pipe 11.

During operation of the refrigeration cycle equipped with the accumulator device constructed as described above, the gas-liquid two-phase refrigerant introduced from the inlet pipe 7 of the suction side pipe into the first container 8A is the first Gas-liquid separation is performed in the container 8A. Then, the liquid refrigerant separated here falls from the drop pipe 10 into the second container 8B by utilizing gravity and is stored therein. The gas refrigerant separated in the first container 8A is returned to the suction side of the compressor 1 via the suction pipe 9. From the bottom of the second container 8B, through the oil return pipe 11 connected to the body of the compressor 1 and the throttle 12 that controls the flow rate, the oil dissolved in the refrigerant flows to the bottom of the compressor 1 together with the liquid refrigerant. Is returned.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the upper part of the first container 8A and the upper part of the second container 8B are connected by a pressure equalizing pipe 13. In this case, the spaces between the first container 8A and the second container 8B are communicated with each other by the pressure equalizing pipe 13 and are at equal pressure, so that the liquid in the first container 8A easily falls into the second container 8B, Gas-liquid separation in one container 8A is facilitated. Other configurations are the same as in the first embodiment.

FIG. 3 shows a third embodiment of the present invention. In this embodiment, an oil return pipe 11 having a throttle 12 from the bottom of the second container 8B is connected to a suction pipe 9 to the compressor 1. In the case of this embodiment, an appropriate amount of oil is returned from the suction pipe 9 to the sliding portion side of the compressor 1 together with the gas refrigerant through the throttle 12, so that proper lubrication in the compressor 1 is always maintained.

As described above, according to the first to third embodiments, the accumulator is composed of the first container 8A and the second container 8B, and the first container 8A is placed above the second container 8B. Since it is positioned, the gas refrigerant that has been gas-liquid separated in the first container is returned to the compressor 1 via the upper suction pipe, and the separated liquid refrigerant containing oil flows through the drop pipe 10 at the bottom of the first container. After that, it is made to flow down to the lower second container 8B and stored there, so that the gas-liquid separation efficiency of the refrigerant is high, and the compressor 1
It is also possible to avoid the occurrence of liquid bag.

FIG. 4 shows an accumulator device according to the fourth embodiment of the present invention. In this embodiment, an electronic expansion valve 120, whose opening and closing is controlled by the controller 20, is provided in place of the throttle 12 of the oil return pipe 11. That is, 120 is the second container 8 of the accumulator.
An electronic expansion valve (hereinafter abbreviated as EEV) 20 provided on the oil return pipe 11 from B to open and close the pipe is a controller that outputs a control signal for controlling the EEV 120.

Reference numeral 19 is a temperature sensor attached to the discharge pipe 2 from the compressor 1 for detecting the temperature of the discharge portion, and 18 is the compressor 1
Is a temperature sensor attached to the housing for detecting the temperature of the housing. Although not shown, the compressor 1
Means for detecting the degree of dilution of the refrigerating machine oil sent to is also provided, and this detection signal is input to the controller 20.

In the accumulator device according to the fourth embodiment shown in FIG. 4, the temperature of the compressor housing is detected by the temperature sensor 18 attached to the housing of the compressor 1 and the temperature sensor attached to the discharge pipe 2. From
The discharge pipe temperature is detected and input to the controller 20.

In the controller 20, based on the temperature detection signals from the temperature sensors 18 and 19, a deviation from a preset temperature and a discharge superheat degree calculated by the deviation are set. The opening degree of the EEV 120 is calculated, further corrected by the detection signal of the dilution degree of the refrigerating machine oil, and the opening degree control signal is sent to the EEV 120. As a result, the liquid refrigerant that contains oil is
It is returned to the optimum flow rate compressor 1 controlled by V120.

FIG. 5 shows an accumulator device according to the fifth embodiment of the present invention. This embodiment is applied when the air conditioner needs a large flow rate of the refrigerant or when the installation space of the accumulator is restricted, and the third container 8B2 is added to the first container 8A and the second container 8B. It has been added.

That is, in FIG. 5, 8B2 is a third container, the upper part of which is connected to the second container 8B via the pressure equalizing pipe 15.
Connected to the top of the Further, the bottom of the third container 8B2 and the bottom of the second container 8B are connected by a liquid leveling pipe 16.
In this embodiment, the oil return pipe 11 is the third container 8
It may be connected to the bottom of B2.

In this embodiment, the accumulators for accommodating the liquid refrigerant containing oil after gas-liquid separation in the first container 8A of the accumulator, that is, the capacities of the second container and the third container have a relatively small space. It is possible to take a large size because of the arrangement without restriction.

FIG. 6 shows an opening / closing time chart of the electronic expansion valve (EEV) in the fourth and fifth embodiments. In FIG. 6, E when the compressor 1 is stopped
The EV opening is VSP (minimum required opening). Further, the EEV opening is kept at the VSP opening until the discharge pipe temperature (or housing temperature) detected by the concentration sensors 19, 18 around the compressor 1 reaches a certain temperature SPH or higher. The temperature detected by the temperature sensors 19 and 18 is SPH.
When the above is reached, the controller 20 changes the E by the opening amount of ΔV.
Open the EV120.

After ΔT, if the temperature is equal to or higher than the temperature SPH detected by the temperature sensors 19 and 18, the EEV12 is again increased by ΔV.
Open 0. The temperature detected by the temperature sensors 19 and 18 is S
This is repeated until it becomes less than or equal to PH. Temperature sensor 1
When the temperature detected by 9, 18 is between SPH and SPL, the opening degree of the EEV 120 is not changed and the temperature sensor 19,
When the temperature detected at 18 becomes equal to or lower than SPL, the controller 20 causes the opening degree of the EEV 120 to be VSP.

FIG. 7 shows a control block diagram of the electronic expansion valve (EEV) 120 by the controller 20. In FIG. 7, reference numeral 21 is a temperature detecting means, which includes the discharge pipe temperature sensor 19 and the housing temperature sensor 18. The controller 20 causes the comparing means 23 to compare whether the detected temperature T ₁ detected by the detecting means is greater than or equal to the set value SPH set in the setting means or less than SPL. If the detected temperature is equal to or higher than SPH, the time ΔT ₁ detected by the time detecting means 24 is compared with the set value ΔT of the timer setting means by the comparing means, and if ΔT ₁ exceeds ΔT, E
The EV opening determination means 27 determines the opening of the EEV 12, and the EE
The V opening output means 28 outputs the opening control signal to the EEV 120.

The comparing means 23 detects the temperature T detected by the sensor.
_{If 1} is less than or equal to the set value SPL, EEV opening degree determining means 27
Determines the opening of the EEV 120 as VSP, and outputs the output means 28.
Outputs the opening degree VSP to the EEV120. If the sensor detection temperature T ₁ is between SPH and SPL in the comparison means 23, the EEV opening determination means 27 determines that the EEV opening is unchanged, and the EEV output means 28 determines the opening as it is.
Output to 120. Also for the control by the discharge superheat degree or the dilution ratio of the refrigerating machine oil, the temperature set values SPH, SP
By appropriately setting L, the same control as above can be performed.

[0041]

The present invention is configured as described above.
According to the present invention, gas-liquid separation is performed in the first container, the gas refrigerant is returned to the compressor, the liquid refrigerant containing oil is sent to the second container, and is stored therein. It is possible to avoid the phenomenon that the efficiency is high and an excessive amount of the liquid refrigerant is returned to the compressor, that is, the liquid back to the compressor is generated, and the damage of the compressor due to this is prevented.

According to the present invention, the temperature condition of the compressor and the degree of dilution of the refrigerating oil are detected, and the electronic expansion valve provided in the oil return line is detected based on the detection signal. Since the opening is controlled, it is possible to accurately control the return flow rate of the liquid refrigerant containing oil after gas-liquid separation to the compressor, and it is possible to maintain a higher gas-liquid separation efficiency, It is possible to reliably prevent the occurrence of a liquid bag.

Further, according to the second aspect or the tenth aspect, since the pressure difference between the first and second containers is eliminated, the liquid refrigerant can be easily moved from the first container to the second container. The gas-liquid separation efficiency is further improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an accumulator device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an accumulator device according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an accumulator device according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an accumulator device according to a fourth embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of an accumulator device according to a fifth embodiment of the present invention.

FIG. 6 is a time chart diagram for explaining the operation in the fourth and fifth embodiments.

FIG. 7 is a control block diagram of a controller in the fourth and fifth modes.

FIG. 8 is a refrigeration cycle diagram of the air conditioner.

FIG. 9 is a schematic configuration diagram of a conventional accumulator device.

[Explanation of symbols]

 1 Compressor 2 Discharge pipe 7 Inlet pipe 8A 1st container 8B 2nd container 9 Suction pipe 10 Drop pipe 11 Oil return pipe 12 Throttle 13,15 Pressure equalizing pipe 16 Liquid leveling pipe 120 Electronic expansion valve 18,19 Temperature sensor 20 Controller 8B2 Third container

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiharu Hagisawa 3-1, Asahimachi, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Air Conditioning Factory

Claims (12)

[Claims] 1. An accumulator device for a refrigeration cycle, which is provided in a suction side pipe to a compressor and performs a gas-liquid separation action of a refrigerant returned to the compressor, wherein the accumulator comprises at least first and second accumulators. It is composed of two containers, the inlet pipe of the suction side pipe and the suction pipe to the compressor are connected to the upper part of the first container, and the bottom part of the first container is connected to the second container. An accumulator device, wherein a pipe is connected, and an oil return pipe connected to the compressor or a suction pipe to the compressor is connected to a bottom portion of the second container. 2. The accumulator device according to claim 1, wherein the upper part of the first container and the upper part of the second container are connected by a pressure equalizing pipe. 3. The first container is arranged at a higher position than the second container, and the liquid separated in the first container is dropped by gravity into the second container. The accumulator device according to claim 1. 4. A heat pump cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, a throttle mechanism and an indoor heat exchanger, wherein the suction side pipe between the compressor and the four-way valve is used. An air conditioner provided with any one of the accumulator devices. 5. An accumulator device for a refrigerating cycle, which is provided in a suction side pipe to a compressor and has a gas-liquid separating action of a refrigerant returned to the compressor, wherein the accumulator comprises at least first and second accumulators. It is composed of two containers, the inlet pipe of the suction side pipe and the suction pipe to the compressor are connected to the upper part of the first container, and the bottom part of the first container is connected to the second container. An electronic device that connects a pipe, connects an oil return pipe connected to the compressor or the suction pipe to the compressor to the bottom of the second container, and further adjusts the opening degree of the pipeline to the oil return pipe. An accumulator device having an expansion valve. 6. The accumulator device according to claim 5, wherein the electronic expansion valve is connected to a controller that outputs a control signal for adjusting the opening degree of the electronic expansion valve. 7. The accumulator device according to claim 6, wherein the controller is configured to control the electronic expansion valve based on a housing temperature of the compressor or a temperature of oil in the housing. 8. The accumulator device according to claim 6, wherein the controller is configured to adjust the opening degree of the electronic expansion valve based on the discharge portion temperature or the discharge superheat degree of the compressor. 9. The accumulator device according to claim 6, wherein the controller is configured to adjust the opening degree of the electronic expansion valve based on the degree of dilution of refrigerating machine oil in the compressor. 10. The accumulator device according to claim 6, wherein the upper part of the first container and the upper part of the second container are connected by a pressure equalizing pipe. 11. The first container is arranged higher than the second container, and the liquid separated in the first container is dropped into the second container by gravity. The accumulator device according to any one of claims 6 to 10. 12. A heat pump cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, a throttle mechanism and an indoor heat exchanger, wherein the suction side pipe between the compressor and the four-way valve is used. An air conditioner provided with any one of the accumulator devices.