JPH0674579A - Refrigerating apparatus - Google Patents

Abstract

PURPOSE:To keep within an appropriate ranges the quantity of the oil returned from the oil-separating means to the compressor and the temperature of the oil in the compressor independent of the differential pressure between the high and low pressures of the compressor and prolong the service life of the compressor. CONSTITUTION:An oil-separating means 18 for separating the oil contained in the discharged gas from the compressor 1 is provided in the discharged gas line 9. An oil-returning means 19 for returning the oil separated by the oil-separating means 18 to the compressor 1 in a quantity variable by throttling is provided between the oil-separating means 18 and the suction gas line 17. An oil temperature-detecting means 20 for detecting the temperature of the oil contained in the compressor 1 and a means of quantitatively controlling the oil returned 22 which, when the detected temperature of the oil is high, increases the throttling of the oil-returning means 19 and, when the temperature is low, decreases the throttling thereof are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system capable of adjusting the amount of oil returned to a compressor.

[0002]

2. Description of the Related Art A typical prior art of a compression unit provided with a device for returning oil to a compressor is disclosed in JP-A-4-12147.
It is publicly known from Japanese Patent No. 9 and its main system is shown in FIG. When the compressor 1 is a scroll compressor, a considerable amount of lubricating oil is sent to the compression chamber for lubrication and cooling in the compression chamber, and after this oil is used for lubrication, most of it is discharged together with the discharge gas. It is sent to the gas pipeline. At this time, since the amount of oil going up together with the discharge gas is quite large, the oil separating device 18 is provided in the discharge gas pipe 9 to separate the oil from the discharge gas, and then the resistance pipe such as a capillary tube is provided. The oil is returned to the compressor 1 through the oil return pipe 31 formed by. Further, a part of the separated oil is injected into the compression chamber of the scroll compressor 1 by the injection path 32.

[0003]

The use of the scroll compressor as a compressor for a refrigerating apparatus has recently become widespread. However, when the refrigerating apparatus is, for example, a low temperature air conditioner, the lubricating surface of the compressor is as follows. The following problems occur. That is, the low-temperature air conditioner has a structure in which the low-pressure pressure is low and the compression ratio is high as compared with a normal air-conditioner, and the normal oil return pipe 31 needs to return the oil while depressurizing the oil. Since the pipe is used, the larger the high / low pressure difference, the larger the oil return amount, and conversely, the smaller the oil return amount, the smaller the oil return amount.

Therefore, when selecting the resistance value (oil return capacity) of the capillary tube, it is assumed that the operating conditions are such that the high pressure is as low as possible and the low pressure is as high as possible, and for example, the high pressure is 10 kg / cm ^2. The low pressure is set to 4 kg / cm ² and the resistance value is selected so that the oil return amount will not be insufficient regardless of the operating conditions.

Regarding the temperature in the compressor, generally, the temperature tends to be higher under the conditions of high high pressure and low low pressure. In such a state, the oil return pipe having the capacity selected in the above procedure is obtained. If the oil is returned by 31, the flow rate becomes excessive, and depending on the operating conditions,
For example, in an operation with a large pressure difference of high pressure of 24 kg / cm ² and low pressure of 0.5 kg / cm ² , not only oil but also discharged gas may be returned together, and the oil temperature may rise significantly. In extreme cases, the oil temperature may rise to 100 ° C.

[0006] When the operation is continued in the high oil temperature, the viscosity of the oil is lowered, and further, the oil is carbonized, and the lubrication inside the compressor is deteriorated. This leads to the problem that annealing occurs and the life is significantly reduced.

An object of the present invention is to keep the amount of oil returned to the compressor and the temperature of the oil in the compressor within an appropriate range regardless of the magnitude of the high / low pressure difference in the compressor. Is to be able to achieve a long life.

[0008]

According to the present invention, in a refrigerating apparatus having a compressor 1, an oil separator is provided in the middle of a discharge gas pipe 9 connected to the compressor 1 to separate lubricating oil contained in the discharge gas. The means 18, the suction gas line 17 connected to the compressor 1, and the oil separation means 18 are provided so as to extend over the lubricating oil separated by the oil separation means 18 via the suction gas line 17. Oil return means 19 for returning the compressor 1 so that the throttle amount can be adjusted
And an oil temperature detecting means 20 for detecting the temperature of the lubricating oil that accumulates in the compressor 1, and a large amount of throttle in the oil returning means 19 when the lubricating oil temperature detected by the oil temperature detecting means 20 is high, A refrigerating device comprising: an oil return amount adjusting means 22 for adjusting the throttle amount to be small when the lubricating oil temperature is low.

In the refrigerating apparatus having the compressor 1, the present invention also includes an oil separating means 18 provided in the middle of the discharge gas pipe 9 connected to the compressor 1 for separating lubricating oil contained in the discharge gas, and a compression unit. The lubricating oil, which is provided so as to extend over the intake gas pipeline 17 connected to the machine 1 and the oil separating means 18, allows the lubricating oil separated by the oil separating means 18 to be adjusted through the intake gas pipeline 17 and the throttle amount. Oil return means 19 for returning to the compressor 1 and the compressor 1
When the differential pressure detection means 21 that results in the differential pressure between the high pressure pressure and the low pressure pressure and the differential pressure detected by the differential pressure detection means 21 are small, the throttle amount in the oil return means 19 is adjusted to a small amount,
The refrigeration apparatus is provided with an oil return amount adjusting means 22 that adjusts the throttle amount more when the differential pressure is large.

The present invention also provides that the oil return means 19 includes a resistance conduit provided with a plurality of capillary tubes 25 in parallel,
And a solenoid valve 26 connected in series to each of the remaining capillary tubes 25 except one,
The refrigeration apparatus according to claim 1 or 2, wherein the oil return amount adjusting means 22 is formed by a controller 27 that selectively drives and opens / closes the electromagnetic valve 26.

According to the present invention, the oil return means 19 is formed by a conduit 29 provided with an electric valve 28 capable of adjusting the valve opening degree stepwise or steplessly, and the oil return amount adjusting means 22.
The refrigerating apparatus according to claim 1 or 2, which is formed by a controller 30 that drives the electric valve 28 to adjust the valve opening degree.

According to the present invention, the oil return means 19 is formed by a pipeline provided in parallel with a capillary tube 25 and an electric valve 28 capable of adjusting the valve opening stepwise or steplessly, and the oil return amount adjusting means 22. The refrigerating apparatus according to claim 1 or 2, which is formed by a controller 30 that drives the electric valve 28 to adjust the valve opening degree.

[0013]

According to the present invention, the lubricating oil contained in the discharge gas is separated and simultaneously cooled by the oil separating means 18 provided in the middle of the discharge gas pipeline 9. The separated lubricating oil is returned to the compressor 1 by the oil returning means 19 via the suction gas pipe line 17. At that time, the oil temperature detecting means 20 detects the temperature of the lubricating oil accumulated in the compressor 1. When the detected oil temperature is high, the oil return amount adjusting means 22 greatly narrows the oil returning means 19, and when it is low, the oil returning means 19 is narrowed down. When the detected oil temperature is high, it means that the high / low pressure difference of the compressor 1 is large and the discharge gas temperature is high. Therefore, the throttle amount is large under the condition of the high / low differential pressure. At the same time as returning the oil equivalent to the required amount, it is possible to suppress the return of the discharge gas having a high temperature, so that the oil can be returned without excess or deficiency while suppressing the temperature rise of the oil in the compressor 1. Be seen.

On the other hand, when the oil temperature detected by the oil temperature detecting means 20 is low, the high / low pressure difference is small and the discharge gas temperature is low, so the high / low pressure difference is small. With a small amount of throttle, the required amount of oil is returned and at the same time a small amount of the discharge gas in the low temperature range is returned, and it is possible to return the oil without excess or deficiency while suppressing the temperature rise of the oil in the compressor 1. Become.

Further, according to the present invention, a differential pressure detecting means 21 is provided instead of the oil temperature detecting means 20, and the compressor 1
The high-low pressure difference of is detected. When the detected pressure difference is high, it is the same state as when the oil temperature is high, and when the pressure difference is low, it is the same state as when the oil temperature is low. Therefore, by adjusting the throttle amount of the oil returning means 19 by the oil returning amount adjusting means 22 in the same manner, the oil returning without excess or deficiency is performed while suppressing the oil temperature rise in the compressor 1.

[0016]

1 is a refrigeration circuit diagram of a first embodiment of the present invention. The embodiment shown in FIG. 1 is composed of an outdoor unit A and an indoor unit B. The outdoor unit A includes a compressor 1, a four-way switching valve 2, a condenser 3, a capillary tube 4 that operates during defrosting, and this capillary tube 4.
A check valve 13, an accumulator 7, a compressor accumulator 8, and an oil separating means 18 and an oil returning means 19 which are realized by an oil separator including a pressure vessel.

As the compressor 1, for example, a scroll compressor is used. In this scroll compressor (hereinafter abbreviated as a compressor) 1, an inlet side end portion of a discharge gas pipeline 9 is connected to a discharge port, and an outlet side end portion of an intake gas pipeline 17 is connected to an intake port. The discharge gas line 9 has a four-way switching valve 2 at the outlet end.
Oil separator 18 connected to the inlet port of
Is installed. The four-way switching valve 2 includes the inlet port, the outlet port, and two inlet / outlet switching side ports, the inlet side end of the intake gas pipeline 17 is connected to the outlet side port, and one of the switching sides is connected. The end of the pipe 16 as a gas pipe is connected to the port, and the end of the pipe 10 as a high-pressure gas pipe is connected to the other switching port. In the suction gas line 17,
Accumulator 7 and compressor accumulator 8
It is installed in series relation from the inflow side.

On the other hand, the condenser 3 is provided with an outdoor fan 23, one end of the heat exchange coil is connected to the other end of the high pressure gas pipe 10, and the other end is also connected to the pipe line 11. It is connected to the exit side end portion of the capillary tube 4 through.
In this capillary tube 4, a check valve 13 is connected in parallel, and one end of a conduit 12 as a liquid pipe is connected to the inlet end.

The oil separator 18 is provided with an oil outlet for taking out oil from the inside of the side wall portion near the bottom of the pressure vessel, and between the oil outlet and the middle of the intake gas pipe line 17. The oil return means 19 is provided so as to extend over the entire length. This oil return means 19 includes two capillary tubes 25.
A and 25B are connected in parallel, and a solenoid valve 26 is directly connected to one capillary tube 25B. One of the capillary tubes 25A is a thin tube of a type having a throttle sufficient to return the minimum necessary amount of oil under the condition that the compressor 1 has a high and low differential pressure, and has an inner diameter of 0.9 mm, for example. A copper tube with a length of 1000 mm is used. The other capillary tube 25B having the solenoid valve 26 in series is a thin tube of a kind having a sufficient throttle to return the required amount of oil under conditions where the compressor 1 does not have a high and low differential pressure. For example, a copper tube with an inner diameter of 1.4 mm and a length of 1000 mm is used.

In the indoor unit B connected to the outdoor unit A having the above-mentioned structure, the expansion valve 5 and the evaporator 6 which are realized by the temperature-sensitive expansion valve having the check valve 15 connected in parallel, The inlet port of the temperature-sensing expansion valve 5 is connected to the other end of the liquid pipe 12, and the end of the heat exchange coil of the evaporator 6 is connected to the other end of the gas pipe 16 by being connected in series via the passage 14. Connected to.

In this way, the outdoor unit A and the indoor unit B form a reversible refrigeration cycle in which the refrigerant system is a closed circuit and the refrigeration cycle and the defrost cycle are switched. In the case of the refrigerating operation, the refrigerant flows in the direction of the solid arrow shown in FIG. 1, so that in the indoor unit B, the low-pressure refrigerant and the indoor fan 2 in the evaporator 6 are discharged.
The latent heat of vaporization is exchanged with the indoor air flowing by driving No. 4, and the room is cooled to a low temperature. In the case of the defrost operation, by switching the four-way switching valve 2, the refrigerant flows in the direction of the broken line arrow shown in FIG.
The evaporator 6 is defrosted by the latent heat of condensation of the high-pressure refrigerant.

During the operation of the compressor 1, the oil separator 18
The oil contained in the discharge gas is separated and stored in the. The accumulated oil is returned to the oil sump of the compressor 1 by the oil returning means 19 through the suction gas line 17. The solenoid valve 26 in the oil return means 19 is opened and closed by a control circuit including an oil temperature detection means 20 and an oil return amount adjustment means 22 realized by a controller 27. The oil temperature detection means 20 is directly attached to the bottom wall portion of the compressor 1 and detects the temperature of the oil in the oil sump portion.
It has A and outputs a different signal depending on whether the detected temperature has risen to 65 ° C. or has dropped to 50 ° C., for example.

On the other hand, the oil return amount adjusting means 22 is formed by, for example, an opening / closing switch, and the oil temperature detecting means 2 is provided.
0 turns off the energization to the solenoid valve 26 according to the signal output by detecting the temperature rise of 65 ° C, and turns on the switch to energize the solenoid valve 26 according to the signal output upon detecting the temperature drop of 50 ° C. It opens and closes.

FIG. 2 shows the relationship between the valve opening of the solenoid valve 26 and the oil temperature of the oil sump, and FIG. 3 shows the electric circuit of the refrigerating apparatus shown in FIG. The compressor 1 and the outdoor fan 23 are driven by the electromagnetic coil 33C being excited and the outdoor electromagnetic switch 33 being turned on when the compressor protection relay 35 is in the closing operation indicating the normal operation state. The indoor fan 34 is also driven by the indoor electromagnetic switch 34 that is turned on in conjunction with turning on the switch 33.

On the other hand, the solenoid 26S of the solenoid valve 26 is
The output contact of the oil temperature detecting means 20 is in the ON state due to the decrease in the detected oil temperature, and the electromagnetic switch 33 is ON,
When the auxiliary contact 33A is turned on, a voltage is supplied from the oil return amount adjusting means 22 to be excited and the valve is fully opened.

On the contrary, either the detected oil temperature rises and the output contact of the oil temperature detection means 20 turns off, or the electromagnetic switch 33 turns off and the auxiliary contact 33A turns off. As a result, the voltage supply from the oil return amount adjusting means 22 is cut off and the valve is fully closed.

Therefore, when the oil temperature is high, the solenoid valve 2
Since 6 is fully closed, the oil introduced from the oil separator 18 flows only through the capillary tube 25A, and the amount of throttle in the oil return means 19 increases, so that the oil is removed under the condition of high and low differential pressure. The minimum amount of oil needed to be returned, that is, the proper amount of oil, is returned. On the other hand, when the oil temperature is low, the solenoid valve 26 is fully opened, so that the oil returned to the compressor 1 flows through both capillary tubes 25A and 25B, the throttle amount is reduced, and the high and low differential pressure is too high. A sufficient amount of oil is returned, i.e., the optimum amount of oil, to return the oil under unsatisfactory conditions.

FIG. 4 is a refrigeration circuit diagram of the second embodiment of the present invention. The second embodiment shown in FIG. 4 is similar to the first embodiment shown in FIG. 1, and corresponding parts are designated by the same reference numerals. It should be noted in this second embodiment that the control element for adjusting and operating the oil return amount adjusting means 22 is
This is a point formed by a differential pressure detecting means 21 instead of the oil temperature detecting means 20 in the first embodiment. The differential pressure detecting means 21 includes a high pressure detector 21A for detecting a high pressure in the discharge gas pipeline 9 and a low pressure detector 21B for detecting a low pressure in the suction gas pipeline 17 in a pressure detecting section. The differential pressure detection means 21 includes both pressure detectors 21A,
21B, the differential pressure between the high pressure and the low pressure is calculated, and the output indicating whether the solenoid valve 26 is fully opened or fully closed is calculated depending on whether this value is large or small. Formed to give through.

FIG. 5 shows the relationship between the high / low pressure differential pressure ΔP and the valve opening of the solenoid valve 26. That is, when the differential pressure ΔP increases and reaches, for example, 15 kg / cm ² , the solenoid valve 26 is fully closed to return an appropriate amount of oil to the compressor 1 under the condition that the differential pressure is applied. In addition, the throttle amount of the oil return means 19 increases. On the other hand, when the differential pressure ΔP decreases and decreases to 13 kg / cm ² , the solenoid valve 26 is fully opened to return an appropriate amount of oil to the compressor 1 under the condition that the differential pressure is not applied. The amount of aperture is reduced.

FIG. 6 is a partial view of the refrigerating circuit of the third embodiment of the present invention, and FIG. 7 is a valve opening-oil temperature relationship diagram of the electric valve 28 shown in FIG. The third embodiment shown in FIG.
Similar to the first embodiment shown in FIG. 1, corresponding parts are designated by the same reference numerals, and parts not shown are the same as corresponding parts in FIG. It should be noted in the third embodiment shown in FIG. 6 that the oil return means 19 is capable of continuously adjusting the valve opening degree by the motor-operated valve 28 and the capillary tube 2.
5 is formed by a pipeline provided in parallel. The motor-operated valve 28 uses, for example, a pulse motor as a drive motor, and is set so that the valve opening degree becomes 100% at 500 pulses and the valve opening degree becomes 20% at 100 pulses. When the oil temperature detecting means 20 detects a low temperature range, for example, 50 ° C., the oil return amount adjusting means 22 realized by the controller 30 is operated, the motor-operated valve 28 is fully opened, and the oil returning means 19 has a small throttle amount. Then, a sufficient amount of oil, that is, an appropriate amount of oil, is returned to the compressor under conditions where the high and low differential pressure is not applied. Further, as the oil temperature rises, the motor-operated valve 28 is gradually throttled to 20% at the time when the valve opening reaches 65 ° C. As a result, the oil return means 19 has a large throttle amount and a high / low differential pressure. An appropriate amount of oil is returned to the compressor 1 under the condition of being marked.

Next, FIG. 8 is a partial view of a refrigeration circuit according to a fourth embodiment of the present invention. The fourth embodiment shown in FIG. 8 is similar to the third embodiment of FIG. 6, corresponding parts are designated by the same reference numerals, and parts not shown are corresponding to those in FIG. It has the same structure as the part that does. What should be noted in this fourth embodiment is that the oil return means 19 is formed by a pipeline provided with the electric valve 28. The motor-operated valve 28 is a pulse motor-driven motor-operated valve in which the valve opening is adjusted in the same manner as the valve opening-oil temperature relationship diagram shown in FIG. 7, and by using a valve having an appropriate diameter, The valve opening is reduced to 20% under conditions of high and low differential pressure, and fully opened to 100% under conditions of low and low differential pressure, and an appropriate amount of oil is returned to the compressor 1 under each condition. It is possible.

In each of the embodiments described above, the compressor 1
When the oil temperature inside is high or the pressure difference between high and low is large, the throttle amount of the oil return means 19 is increased to substantially increase the pipe resistance, and conversely when the oil temperature is low or the pressure difference between high and low is small. It becomes possible to reduce the piping resistance by reducing the throttle amount, and it is possible to prevent an abnormal rise in the oil temperature.

[0033]

As described above, according to the present invention, the throttle amount of the oil return means 19 is adjusted to some extent according to the level of the oil temperature in the compressor and the magnitude of the high / low pressure difference. Therefore, it is possible to avoid an abnormal increase in oil temperature due to the return of the discharge gas, especially under conditions where the oil temperature is high.
The life of the compressor is secured by keeping the oil temperature within an appropriate range, and the reliability of the device is improved.

[Brief description of drawings]

FIG. 1 is a refrigeration circuit diagram of a first embodiment of the present invention.

2 is a valve opening-oil temperature relationship diagram of the solenoid valve 26 shown in FIG. 1. FIG.

FIG. 3 is an electric circuit diagram of the first embodiment shown in FIG.

FIG. 4 is a refrigeration circuit diagram of a second embodiment of the present invention.

5 is a valve opening-high / low pressure differential pressure relationship diagram of the solenoid valve 26 shown in FIG. 4;

FIG. 6 is a partial view of a refrigerating circuit according to a third embodiment of the present invention.

7 is a valve opening-oil temperature relationship diagram of the motor-operated valve shown in FIG.

FIG. 8 is a partial view of a refrigeration circuit according to a fourth embodiment of the present invention.

FIG. 9 is a main part systematic diagram in a compression unit of a prior art.

[Explanation of symbols]

 1 Compressor 9 Discharge Gas Pipeline 17 Intake Gas Pipeline 18 Oil Separation Means 19 Oil Return Means 20 Oil Temperature Detection Means 20A Temperature Sensing Part 21 Differential Pressure Detection Means 21A High Pressure Pressure Detectors 21B Low Pressure Pressure Detectors 22 Oil Return Amount Adjustment Means 25A, 25B Capillary tube 26 Solenoid valve 27 Controller 28 Motorized valve 30 Controller

Claims (5)

[Claims] 1. A refrigerating apparatus having a compressor (1), wherein an oil separation means (18) provided in the middle of a discharge gas pipe (9) connected to the compressor (1) for separating lubricating oil contained in the discharge gas, and a compressor (1) Intake gas line 17 and oil separating means 18 to be connected
And an oil returning means 19 for returning the lubricating oil separated by the oil separating means 18 to the compressor 1 via the suction gas pipe line 17 so that the throttle amount can be adjusted, and the inside of the compressor 1. The oil temperature detecting means 20 for detecting the temperature of the lubricating oil accumulated in the oil, and when the lubricating oil temperature detected by the oil temperature detecting means 20 is high, the throttling amount in the oil returning means 19 is adjusted to be large, and when the lubricating oil temperature is low, A refrigerating apparatus, further comprising: an oil return amount adjusting means 22 for adjusting the throttling amount to be small. 2. In a refrigeration system having a compressor 1, an oil separation means 18 provided in the middle of a discharge gas pipe 9 connected to the compressor 1 for separating lubricating oil contained in the discharge gas, and a compressor 1 Intake gas line 17 and oil separating means 18 to be connected
And an oil return means 19 for returning the lubricating oil separated by the oil separation means 18 to the compressor 1 via the suction gas pipe line 17 so that the throttle amount can be adjusted, and When the differential pressure detecting means 21 for detecting the differential pressure between the high pressure and the low pressure and the differential pressure detected by the differential pressure detecting means 21 is small, the throttle amount in the oil returning means 19 is adjusted to be small, and the differential pressure is large. A refrigeration system comprising: an oil return amount adjusting means 22 for adjusting the throttle amount to a large extent. 3. The oil return means 19 is formed by a resistance conduit having a plurality of capillary tubes 25 in parallel, and a solenoid valve 26 connected in series to each of the remaining capillary tubes 25 except one. The refrigeration system according to claim 1 or 2, wherein the oil return amount adjusting means 22 is formed by a controller 27 that selectively drives and opens / closes the electromagnetic valve 26. 4. A pipeline 29 in which the oil return means 19 includes an electric valve 28 capable of adjusting the valve opening stepwise or steplessly.
The refrigerating apparatus according to claim 1 or 2, wherein the oil return amount adjusting means 22 is formed by a controller 30 that drives the electric valve 28 to adjust the valve opening degree. 5. The oil return means 19 is formed by a pipeline provided in parallel with a capillary tube 25 and an electric valve 28 capable of adjusting the valve opening stepwise or steplessly, and the oil return amount adjusting means 22 is the above-mentioned. A controller 30 for driving the motor-operated valve 28 to adjust the valve opening.
Alternatively, the refrigerating apparatus according to 2.