JPH04203760A - Oil lubrication system for compressor for refrigeration equipment - Google Patents

Abstract

PURPOSE:To enable execution of enough lubrication of the interior of a compressor during the starting of drive and to prevent wear and the damage of a slide part because of oil running out by a method wherein only during the starting of drive of a compressor, lubricating oil is fed to the suction line of a compressor from an oil tank to which lubricating oil is fed only during the stop of the compressor. CONSTITUTION:A motor 10 and solenoid valves SV1 and SV2 are controlled by means of a control means 18. The control means 18 opens the solenoid valve SV1 when the motor 10 is stopped, and lubricating oil 11 in a compressor 1 is fed to an oil tank 13. When the motor 10 is run, the solenoid valve SV1 is closed, the lubricating oil 11 is prevented from being fed to the oil tank 13 from the compressor 1. The lubricating oil 11 fed to the oil tank 13 during the stop of the motor 10 is pressurized by means of a refrigerant fed from a high pressure chamber 8 through a pressure pipe 42 when the motor 10 is run and fed to a suction line 14 through a lubricating oil pipe 17 to perform enough lubrication of the compressor 1 during the starting of drive. The solenoid valve SV2 performs reliable operation to feed the lubricating oil 11 only during the starting of running of the compressor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for lubricating a compressor for circulating refrigerant in a refrigeration system with lubricating oil.

2. Description of the Related Art Conventional oil lubrication systems for compressors for refrigeration equipment are disclosed, for example, in Japanese Patent Application Laid-Open No. 61-46859 and Japanese Utility Model Application No. 61-1627.
This is shown in Publication No. 62. In these prior technologies, the lubricating oil that has solidified or gelled in the evaporator and piping on the low-temperature side of the binary refrigeration system is returned to the compressor to prevent functional deterioration of the evaporator, etc. , ensuring that the compressor is sufficiently lubricated. For this reason, a portion of the refrigerant discharged from the compressor is directly guided into the evaporator, the attached lubricating oil is removed, and the refrigerant is sucked into the compressor.

Problems to be Solved by the Invention In the conventional oil lubrication system for a compressor for a refrigeration system,
The compressor is configured to lubricate the compressor by returning lubricating oil that adheres to the inside of the evaporator during operation of the compressor to the compressor.

According to such a configuration, it is possible to prevent lubricating oil from adhering to the evaporator during operation of the refrigeration equipment, resulting in insufficient lubrication of the compressor. It cannot be lubricated. That is, in such a configuration, since the amount of lubricating oil adhering to the inside of the evaporator is small, the amount of lubricating oil returning to the compressor is also small. When the compressor is started, lubricating oil is flowing out from the sliding parts that have been in a stopped state, and there is a shortage of lubricating oil. When the compressor is in such an oil-starved state and the amount of lubricating oil mixed in the refrigerant sucked into the compressor is small, the sliding parts of the compressor are likely to wear out.

An object of the present invention is to provide an oil lubrication device for a compressor for a refrigeration system that can solve the above-mentioned technical problems and provide sufficient lubrication when starting up the compressor.

Means for Solving the Problems The present invention provides: a compressor; an oil tank for storing lubricating oil; an oil supply pipe for supplying the lubricating oil in the compressor to the oil tank; and an oil supply pipe interposed in the middle of the oil supply pipe. an oil lubrication pipe that guides lubricating oil from the lower part of the oil tank to the suction line of the compressor; and an oil lubrication pipe that guides refrigerant discharged from the compressor to the oil tank;
A pressurizing pipe for pressurizing lubricating oil in an oil tank; and a control means for controlling the solenoid valve SVI to close when the compressor is driven and to open the solenoid valve SVI when the compressor is stopped. This is an oil lubrication system for a compressor for a refrigeration system.

Function According to the present invention, lubricating oil in the compressor is supplied to the oil tank via the oil supply pipe. A solenoid valve is provided in the middle of the oil supply pipe. The solenoid valve is controlled by the control means to open when the compressor stops operating. Thereby, the lubricating oil in the compressor is supplied into the oil tank when the compressor is stopped.

The control means controls the solenoid valve to close when the compressor is driven. Therefore, after the compressor starts driving,
No lubricating oil is supplied to the oil tank. When the compressor is driven, the lubricating oil stored in the oil tank is pressurized by the refrigerant discharged from the compressor and guided into the oil tank via the pressurizing pipe. An oil lubrication pipe is provided at the bottom of the oil tank to introduce pressurized lubricating oil to the suction line of the compressor. Therefore, pressurized lubricating oil is supplied to the suction line of the compressor via the oil lubricating pipe. The compressor is sufficiently lubricated by this supplied lubricating oil.

Since the solenoid valve is closed while the compressor is running, the lubricating oil that was stored in the oil tank when the compressor starts running is supplied to the suction line via the oil lubrication pipe, and then the lubricating oil is released from the oil tank. The compressor is no longer lubricated by lubricating oil. In this way, sufficient lubrication can be provided only at the start of driving the compressor.

Embodiment FIG. 1 is a refrigerant piping system diagram for explaining an oil lubrication system for a compressor of a refrigeration system according to an embodiment of the present invention. The compressor 1 compresses a refrigerant such as Freon R-22 and discharges it toward the condenser 2 . In the condenser 2, the compressor 1
Removes heat from the gas refrigerant discharged from the refrigerant and condenses it. The liquid refrigerant condensed in the condenser 2 is led to an expansion valve 4 via a pipe 3. In the expansion valve 4, the pressure of the liquid refrigerant is adiabatically reduced from the discharge pressure of the compressor 1 to a pressure much lower than the discharge pressure.

The liquid refrigerant whose pressure has been reduced by the expansion valve 4 is guided to the cooler 5, which is an evaporator. In the cooler 5, since the pressure is low, the liquid refrigerant can evaporate even at a low temperature, and absorbs latent heat for evaporation from the surroundings. Thereby, the cooler 5 can cool the surroundings. The gas refrigerant evaporated by the cooler 5 is guided to an accumulator 6 for gas-liquid separation. In the accumulator 6, the liquid refrigerant contained in the gas refrigerant is separated, and only the gas refrigerant is sucked into the compressor 1 via the suction line 14.

By circulating the refrigerant in this manner, the heat absorbed in the cooler 5 is released from the condenser 2, and the cooler 5 performs freezing.

Compression I! in this embodiment! Reference numeral 1 denotes a hermetic rotary compressor, in which a high pressure chamber 8 is formed within a compressor dome 7, and a further sealed compression chamber 9 is formed within the high pressure chamber 8.

A motor 10 is also provided in the high pressure chamber 8 to change the volume of the compression chamber 9 for compression. Lubricating oil 11 for lubricating the motor 10 and the like is stored in the lower part of the high pressure chamber 8 .

Lubricating oil 11 stored in the high pressure chamber 8 is supplied to an oil tank 13 via an oil supply pipe 12 communicating with the lower part of the high pressure chamber 8 . A solenoid valve SV1 is interposed in the middle of the oil supply pipe 12. A portion of the refrigerant discharged from the compressor 1 is guided from the upper part of the high pressure chamber 8 to the oil tank 13 via the pressurizing pipe 42 . In the middle of the pressurizing pipe 42, there is a first capillary 15.
is interposed to adjust the amount and pressure of the refrigerant introduced into the oil tank 13 via the pressurizing pipe 42. The lubricating oil 11 stored in the oil tank 13 is supplied to the suction line 14 from the lowest part of the oil tank 13 via an oil lubrication pipe 17 . A solenoid valve Sv2 and a second capillary 16 are interposed in the middle of the oil-lubricated pipe 17. The second capillary 16 is an oil-lubricated pipe 1
The amount and pressure of lubricating oil 11 supplied to suction line 14 via line 7 are adjusted.

The motor 10 and the solenoid valves SVI, SV2 are connected to the control means 1
8. When the motor 10 is stopped, the control means 18 opens the solenoid valve SVI and supplies the lubricating oil 11 in the compressor 1 into the oil tank 13. When driving the motor 10, the solenoid valve SVI is closed to prevent the lubricating oil 11 from being supplied into the oil tank 13 from the compressed all. In this way, when the motor 10 is stopped, the oil tank 13
When the motor 10 is driven, the lubricating oil 11 supplied therein is pressurized by the refrigerant from the high pressure chamber 8 via the pressurizing pipe 42 and is supplied to the suction line 14 via the oil lubricating pipe 17. The lubricating oil 11 thus supplied to the suction line 14 can sufficiently lubricate the compressor 1 at the start of driving.

Therefore, it is desirable that the lubricating oil 11 is supplied from the oil lubricating pipe 17 to the suction line 14 as close as possible to the suction port of the compressor 1. The solenoid valve SV2 provided in the oil lubricating pipe 17 ensures the operation of supplying the lubricating oil 11 only when the compressor 1 starts driving.

FIG. 2 is a simplified vertical sectional view showing the configuration of the compressor 1 in the embodiment shown in FIG. 1'. This compressor 1 is a hermetic rotary compressor as described above. The inside of the compressor 1 is hermetically sealed by a compressor dome 7 and a case 19, and a high pressure chamber 8 is configured. Hyperbaric chamber 8
A further sealed compression chamber 9 is formed inside. The volume of the compression chamber 9 is changed by the motor 10, and refrigerant is sucked and compressed. Lubricating oil 11 is stored in the lower part of the high pressure chamber 8 and is passed through an oil supply pipe 12 to an oil tank 1.
3. Refrigerant from the accumulator 6 is sucked into the compression chamber 9 via a suction line 14 . Motor 1
0 is an induction motor in which a rotor 21 and a stator 22 are arranged concentrically around a shaft 20, windings 23 are provided above and below the rotor and stator, and a bearing 24 is provided inside the winding 23. It consists of

A shaft 20 of the motor 10 extends downward and rotationally drives a rotary compression section 25 in which a compression chamber 9 is formed. The rotary compression section 25 forms a compression chamber 9 sealed by a cylinder 26 and an upper and lower partition plate 27 and a lower partition plate 28 arranged above and below the cylinder 26 . These cylinders 26 and the upper and lower partition plates 27, 28 are arranged such that a roller 3o having an outer diameter smaller than the inner diameter of the cylinder 26 is in contact with the inner circumferential side of the six cylinders 26 fixed by bolts 29 at one point. There is. A crankshaft 31 is fitted inside the roller 3o. A shaft 2o of a motor 1o is fixed at a position eccentric from the center of the crankshaft. It is formed in the space not occupied by the roller 30 in the space formed by the compression chamber, the cylinder 26, and the upper and lower partition plates 27,28. When the shaft 20 is rotated by the motor 1o, the roller 30 also moves, and the position where the compression chamber 9 is formed also changes.

The compression chamber 9 is provided with a suction port 32 through which refrigerant sucked through the suction line 14 flows. Further, a discharge valve 34 is provided for causing the refrigerant to flow out from a discharge hole 33 provided in one partition plate 26 when the refrigerant in the compression chamber 9 is compressed and its pressure becomes equal to or higher than the discharge pressure. When the discharge valve 34 opens, the refrigerant flows into the high pressure chamber 8 as indicated by the arrow 35. The refrigerant in the high pressure chamber 8 is
It is led to the condenser 2 from a discharge port 36 provided in the .

Furthermore, the refrigerant in the high pressure chamber 8 also flows out to the first capillary 15 via the pressurizing pipe 42 . Suction port 32 and discharge hole 3
3 are separated by vanes 39 in FIG. 3, which will be described later. In FIG. 2, the vane 39 is omitted for convenience of illustration.
The relative positions of the suction port 32 and the discharge hole 33 are changed.

The lower end of the shaft 20 of the motor 10 is immersed in lubricating oil 11 and is provided with a pump 37 . The pump 37 pumps up the lubricating oil 11 using centrifugal force. The lubricating oil 11 pumped up by the bong 737 lubricates the bearing 24 of the motor 1o through the pore 38 provided inside the shaft 20.

The rotary compression section 25 is lubricated by lubricating oil contained in the refrigerant sucked through the suction port 32 as minute oil droplets. The lubricating oil 11 stored in the lower part of the high pressure chamber 8 becomes minute oil droplets in the high pressure chamber 8 and mixes with the gas refrigerant.
It is discharged from the discharge port 36, circulates through the refrigerant circuit, and reaches the suction port 3.
2 are inhaled. Therefore, even if the motor 1o is started from a stopped state, it takes time until sufficient lubricating oil is supplied to the compression chamber 9. The lubricating oil 11 stored in the lower part of the high pressure chamber 8 may have a liquid level above the discharge valve 34, as shown in FIG. Even if the discharge valve 34 opens, the pressure in the compression chamber 9 is higher than the pressure in the high pressure chamber 8, so the lubricating oil 11 flows into the discharge hole 3.
3 into the compression chamber 9. The lubricating oil 11 may also lubricate the low-pressure compression section 25 through a gap between the bearings between the upper and lower partition plates 27 and 28 and the shaft 2o. However, since the rotary compression section 25 is configured to make such a gap as small as possible, the lubrication provided by the lubricating oil 11 through such a gap is not sufficient.

FIG. 3 is a cross-sectional view of the rotary compression section 25 taken along the section line --- in FIG. The vane 39, which is not shown in FIG. 2, is urged inward in the radial direction of the cylinder 26 by a spring 4o. The tip of the vane 39 is
It contacts the outer periphery of the roller 3o at one point. The length of the vane 39 protruding inside the cylinder 26 is the length of the roller 3
It changes depending on the position of o. The compression chamber 9 is divided into two spaces by a contact point between the roller 3o and the tip of the vane 39 or the inner circumference of the cylinder 26. roller 30 is arrow mark 4
1, the volume of the space facing the discharge hole 33 decreases, and the gas refrigerant in this space is compressed. When the pressure reaches such a level that the discharge valve 34 opens, refrigerant is supplied to the high pressure chamber 8 through the discharge hole 33 . As the refrigerant is compressed in this manner, the volume of the space facing the suction port 32 increases, and the refrigerant is sucked into the space. roller 3
0 is rotated and the contact points of the roller 3o and the vane 39 match the contact points of the outer periphery of the roller 3o and the inner periphery of the cylinder 26, the space that was previously on the suction side becomes the compression side, The space that was on the compression side becomes the suction side.

In this manner, a rotary compressor using a rotating piston system operates.

FIG. 4 is a diagram for explaining the operation of the control means 18. FIG. 4(1) shows the control state of the rotational speed when the control means 18 drives the motor 10 to rotate at time t1. Such control is performed by controlling the output frequency of the inverter for driving the motor 10.

When the drive is started at time t1, the rotation speed becomes 01 at time t3, and from time t4 onward, the rotation speed is controlled to be constant at n2.One rotation speed 01 is, for example, 2000 revolutions per minute, and the rotation speed n2 is, for example, 3 per minute
000 to 6000 rotations.

FIG. 4(2) shows a state in which the control means 18 controls the solenoid valve SV1. The solenoid valve SV1 is open in the ON state before time t1, and is closed in the OF or F state after time t1. During the period when solenoid valve SV1 is open,
Lubricating oil 11 in the cooler 1 is supplied to an oil tank 13 via an oil supply pipe 12. FIG. 4(3) shows the control state of the solenoid valve SV2 by the control means 18. Solenoid valve SV2 is
It is in the ON state and open for the period from time t1 to t2, and is in the OFF state and closed for the remaining period. Therefore, the lubricating oil 11 stored in the oil tank 13 at time t
It is supplied to the suction line 14 only during the period from 1 to t2. Since the pressure of the refrigerant in the suction line 14 is small,
The supplied lubricating oil turns into minute oil droplets and is sucked into the compression chamber 9 to provide lubrication. The second capillary 16 provided in the middle of the oil lubricating pipe 17 is used to adjust the amount and pressure of the lubricating oil 11 supplied to the suction line 14 and to ensure smooth mixing with the gas refrigerant in the suction line 14. ing. In this embodiment, since the solenoid valve SV2 is provided, the lubricating oil 1 is pushed out from the oil tank 13 into the oil lubricating pipe 17.
Even when 1 runs out, the pressurizing pipe 42 and the oil lubricating pipe 1
7, it is possible to prevent the refrigerant discharged from the compressor 1 from being directly bypassed to the suction side of the compressor 1.

In addition, first and second capillaries 15. Since 'l'6 is provided, even if the solenoid valve SV2 is not provided, it is possible to reduce the amount of refrigerant bypassed from the discharge side to the suction side of the compressor 1 while the compressor 1 is operating. It is possible to reduce the decrease in refrigeration capacity.

Although in the above embodiment the pressure tube 42 is directly connected to the compressor dome 7, the compression! 11 to condenser 2
Of course, it is also possible to branch out from the middle of the piping. Further, although the compressor 1 is a rotary piston type rotary compressor, other types of compressors may be used as long as the lubricating oil 11 is stored on the high pressure side. Of course.

The capacity of the oil tank 13 can be suitably set to about 50% of the displacement of the piston per rotation of the compressor 1. According to the inventor's experiment, the rotation speed of the compressor 1 is controlled as shown in FIG. 4 (1), and the rotation speed is 0.
By the time it reaches 2000 revolutions per minute, the oil tank 13
It has been confirmed that all of the lubricating oil 11 stored in the suction line 14 can be discharged to the suction line 14 side. The oil lubricating pipes 1 and 7 are preferably connected to the oil tank 13 at the lowest part of the oil tank 13 in order to drain all of the lubricating oil 11 stored therein. It is desirable that the lubricating oil 11 is supplied from the oil lubricating pipe 17 to the suction line 14 at a position as close as possible to the suction port 32 of the compressor 1. If the position is close, compression I! At the start of driving of the compressor 11, the inside of the compression chamber 9 can be quickly lubricated, and the supplied lubricating oil 11 can be prevented from adhering to the inside of the cooler 5 or the like.

Further, as in the present embodiment, a solenoid valve SV2 is provided in the middle of the oil lubricating pipe 17, and by keeping the oil lubricating pipe 17 closed except when driving the compressor 1, refrigerant is discharged from the compressor 1. It is possible to prevent the lubricating oil 11 from being directly inhaled, increasing the discharge temperature, and deteriorating the lubricating oil 11. However, as described above, if a capillary 15, 16 or the like is provided in the middle of the pressurizing pipe 42 or the oil lubricating pipe 17, the refrigerant that is directly bypassed from the discharge side to the suction side of the compressor 1 can be It is possible to limit the amount and prevent overheating of the discharged gas.

Effects of the Invention As described above, according to the present invention, lubricating oil can be supplied to the suction line of the compressor only when the compressor starts driving, instead of lubricating oil being supplied from the oil tank only when the compressor is stopped. . Therefore, the inside of the compressor can be sufficiently lubricated when the compressor starts driving, and it is possible to prevent wear and damage to the sliding parts due to lack of oil.

In addition, since lubricating oil is not supplied to the oil tank while the compressor is operating, excess lubricating oil is not returned to the suction line via the oil lubricating pipe, and the lubricating oil is stored inside the evaporator on the low temperature side. It is possible to prevent the heat exchange efficiency from decreasing due to adhesion to the heat exchanger.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant piping system diagram showing one embodiment of the present invention;
The figure is a vertical cross-sectional view showing a simplified configuration of the compressor 1 in the embodiment shown in the first figure, FIG. The figure is a diagram for explaining the control state by the control means 18 shown in the first figure. 1...Compressor, 2...Condenser, 3...Pipe line, 4...
・Expansion valve, 5... Cooler, 6... Accumulator,
8...High pressure chamber, 9...Compression chamber, 10...Motor, 1
DESCRIPTION OF SYMBOLS 1... Lubricating oil, 12... Oil supply pipe, 13... Oil tank, 14... Suction line, 17... Oil lubricating pipe, 1
8... Control means, 20... Axis, 25... Rotary compression section, 26... Cylinder, 30... Roller, 32...
...Suction port, 33...Discharge hole, 34...Discharge valve, 3
6...Discharge port, 39...Vane, 42...Pressure pipe agent Patent attorney Number of strokes Keiichibetsu 1st figure 1 compression vessel 3rd figure 4th figure

Claims (1)

[Claims] (1) A compressor 1, an oil tank 13 for storing lubricating oil 11, an oil supply pipe 12 for supplying the lubricating oil 11 in the compressor 1 to the oil tank 13, and an oil supply pipe 12 in the middle of the oil supply pipe 12. An interposed solenoid valve SV1 supplies lubricating oil 11 from the lower part of the oil tank 13 to the compressor 1.
an oil lubricating pipe 17 leading to the suction line 14 of the compressor 1;
a pressurizing pipe 42 for guiding the refrigerant discharged from the oil tank 13 to the oil tank 13 and pressurizing the lubricating oil 11 in the oil tank 13; and when the compressor 1 is driven, the solenoid valve SV1 is closed and the compressor 1 is stopped. An oil lubrication system for a compressor for a refrigeration system, characterized in that it includes a control means 18 for controlling the solenoid valve SV1 to open at times.