JPH0139914Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is an oil-cooled rotary compressor, that is, a compressor that injects lubricating oil into the compression chamber of the compressor to cool, lubricate, and seal the working space of the compressor. The present invention relates to a rotary compressor that performs operations.

[Conventional technology]

Conventionally, this type of compressor, for example, a screw compressor,
A pump for feeding and injecting lubricating oil into the compression chamber of the compressor is provided at the shaft end of the screw rotor, and a mixed fluid of the compressed gas discharged from the discharge port of the compressor and the lubricating oil is sent to a receiver via a check valve. After being pressure-fed to a tank and separating the compressed gas and lubricating oil by a built-in separator in the receiver tank, the compressed gas is taken out through a gas outlet and used as appropriate. On the other hand, the lubricating oil is again injected into the compressor by the pump and is circulated.

As is known, when the amount of compressed gas used in the receiver tank decreases or the use of compressed gas is stopped,
The pressure inside the receiver tank increases to a constant value (for example, 7Kg/
cm ² ), the regulator or solenoid valve operates, and the intake block type unloader installed at the compressor's intake port reduces or completely closes the intake port area, adjusts the intake amount of compressed gas, and , when fully closed, shifts to no-load operation to reduce power consumption of the compressor drive motor, and in the case of engine-driven types, reduces power consumption by lowering the rotational speed of the engine. The government is beginning to aim to achieve this goal.

[Problem that the invention attempts to solve]

When the compressor is stopped, the high-pressure compressed gas that is being discharged and the lubricating oil flow back into the compression chamber of the cylinder in a gas-liquid mixture, resulting in the lubricating oil remaining in the compression chamber. In addition, there is a drawback that the compressor is instantaneously reversed due to the backflow phenomenon into the compression chamber, damaging various parts.

Furthermore, during no-load operation, due to the blockage of the unloader, at least the vicinity of the suction port in the cylinder, that is, the suction side, is in a low pressure state, and
Since the inside of the receiver tank maintains a high pressure state, when the compressor stops in this state, the tank internal pressure is added to the lubricating oil in the reservoir provided in the receiver tank, and this pressure difference causes the pressure to flow into the compression chamber of the cylinder. The lubricating oil is gradually forced into the compression chamber through the lubricating oil supply path, and eventually a large amount of lubricating oil accumulates in the cylinder. . especially,
As seen in the invention of JP-A No. 50-60811, the lubricating oil flowing downward into the discharge chamber of the compressor is constantly sent to the receiver via piping by another pump installed in parallel with the lubricating oil injection pump. By recovering the compressor into a tank, the back pressure applied to the screw rotor in the discharge chamber during no-load operation of the compressor is removed;
In a compressor configured to reduce the driving force of the compressor, the inside of the cylinder is in a complete vacuum state when the compressor is stopped, so if the compressor is stopped in this state, Due to the negative pressure in the working space, a large amount of lubricating oil flows from the reservoir into the compression chamber of the cylinder via one pump provided at the end of the screw rotor shaft. Needless to say, such an inflow of lubricating oil is unavoidable unless the pressure difference between the compression chamber and the receiver tank is resolved, and as a result, the amount of lubricating oil in the cylinder increases to an unnecessary extent. As a result, the next time the compressor is started, it causes failures such as oil lock, burnout of the motor, and inability to start the engine.

[Means for solving problems]

The present invention was developed to eliminate the causes of failures in conventional machines, and the configuration will be explained with reference to the illustrated embodiment.
0 is provided with a check valve 39 at the discharge port 38, and the inside of the receiver tank 40 connected through the check valve is divided by a separator 42, and the portions before and after the compressed gas passes through the separator are respectively connected to lubricating oil reservoirs. 65
The oil reservoir section 50 is divided and formed, and the reservoir section 65 is connected via a pump 24 provided at the end of the shaft of the rotor 21 to an injection port 27 that opens into a compression chamber in the middle of compressing intake gas of the cylinder. Further, the reservoir section 65 is connected to the discharge port via another pump 25 provided at the shaft end of the rotor 21, and the oil reservoir section 50 is connected to the discharge port 38 on the discharge side of the injection port 27. A solenoid valve 60 is installed in the compression chamber in a position that does not communicate with the
At the same time, the solenoid valve is connected to a power source through a pressure switch 43 attached to the receiver tank and a compressor stop switch PB-S, and the solenoid valve is opened during load operation of the compressor. Then, the suction port 26 and the discharge port 38 are respectively closed by an unloader and a check valve,
Further, after a no-load operation with the solenoid valve closed, the solenoid valve 60 is opened simultaneously with the stop of the compressor to communicate the oil sump with the compression chamber of the cylinder. be.

[Effect]

Therefore, during load operation of the compressor, the pressure switch 43 opens the solenoid valve 60 and the oil sump 5
0 lubricating oil is collected into the compression chamber through a collection hole 61 that opens at a position that is on the discharge side of the injection port and does not communicate with the discharge port.

Further, at the same time as the transition to no-load operation, the pressure switch 43 closes the electromagnetic valve to stop collecting the lubricating oil in the oil sump 50, and the check valve at the discharge port is closed to block the suction port. and other pump 2
5, the lubricating oil and the compressed fluid in a gas-liquid mixed state staying below the discharge port 38 are collected into the reservoir 65, and the back pressure of the compressor rotor in the discharge port is removed. is under negative pressure.

At the same time as the compressor is stopped, the solenoid valve is opened to communicate the inside of the compression chamber with the oil sump 50 separated by the separator in the receiver tank, so that the compressed gas in the oil sump 50 is transferred into the cylinder. When the compressor is stopped, the sealing ability of the lubricating oil between each compression chamber is lost, so the introduction of the compressed gas quickly brings the pressure in the cylinder and the receiver tank to the same pressure, and the lubricating oil is removed. The pressure difference between the oil reservoir 65 and the compression chamber of the cylinder is eliminated to prevent lubricant oil from flowing from the lubricant reservoir 65 through the pump 24 and the injection port 27 into the compression chamber of the cylinder. .

[Example] Hereinafter, details of the present invention will be explained based on an illustrated example.

FIG. 1 shows an example in which the present invention is applied to the screw compressor disclosed in Japanese Patent Application Laid-Open No. 50-60811 mentioned above, in which 10 is an unloader, 20 is a cylinder, and 40 is a receiver tank. . A shaft end 22 on the suction side of the male rotor 21 supported in the cylinder 20 is connected to a motor (not shown), and a pump 24 is connected to the shaft end of the male rotor 21 on one end wall 23 side of the cylinder 20, that is, on the discharge side. and another pump 25 are arranged in parallel. The male rotor 21 meshes with a female rotor (not shown) inside the cylinder 20, and both rotors rotate in opposite directions, suck working gas through the unloader 10 from the suction port 26 of the cylinder 20, and move the working gas from the suction side to the discharge side. The compressed gas is compressed by a compression chamber whose volume gradually decreases, and the compressed gas is supplied to the receiver tank 40 from the discharge port 38 of the compressor via the check valve 39. On the other hand, the lubricating oil, most of which has been separated from the compressed gas in the receiver tank, flows down to the lubricating oil reservoir 65 located at the lower part of the receiver tank, from there it is cooled by the oil cooler 41, and the male rotor 21
The injection port 2 provided in the casing 20' forming the cylinder 20 is connected to the first pump 24 provided at the shaft end of the cylinder 20 via an oil supply pipe equipped with an oil amount adjustment valve 29.
7 into the compression chamber, cooling the compression chamber,
It is discharged together with the compressed gas to the discharge port 38 while performing lubrication and sealing action, and from there flows back to the receiver tank 40 via the check valve 39, whereupon the above-mentioned action is repeated. Another pump 25 installed in parallel with the first pump 24 sucks the compressed fluid in a gas-liquid mixed state with the lubricating oil separated at the discharge port 38 and flows through the receiver tank 40 at all times during operation of the compressor. Collected into the storage section 65 of.

The compressed gas in a gas-liquid mixed state that is pumped into the receiver tank 40 together with the lubricating oil is used after the lubricating oil is separated by the partition plate 45 and the separator 42 through the piping 46 and the pressure holding valve. When the amount of compressed gas used in the receiver tank 40 decreases and the use of compressed gas is stopped, the pressure inside the receiver tank exceeds a predetermined value (7 kg/cm ² ).
At that time, the pressure switch 43, which is activated by detecting the pressure in the receiver tank 40, cuts off the voltage application to the electromagnetic valve 11, which is closed when energized, and opens the electromagnetic valve 11.
Receiver tank internal pressure is supplied to the primary side diaphragm chamber of the unloader 10 through the pipe 12 connected to the pipe 46 of the unloader 10 , presses the diaphragm 13 , and the unloader valve 14 closes the intake port 15 .

Reference numeral 16 designates a pressure reducing valve, and the inlet side of the pressure reducing valve 16 is connected to a branch pipe 12 that connects to the electromagnetic valve 11, while the outlet side of the pressure reducing valve 16 is connected to an unloader 10.
Diaphragm 1 communicates with the secondary diaphragm chamber of
3, the operating pressure of the unloader valve 14 can be adjusted. The intake air of the compressor becomes zero due to the blockage of the intake port 15 by the unloader valve 14, and the high-pressure compressed gas in the discharge port 38 is sucked together with lubricating oil by the pump 25 and discharged to the receiver tank 40. valve 39
is the pressure from the receiver tank 40 and the check valve 39
It is closed by the bias of a spring (not shown) provided in the
Shift to no-load operation. Therefore, the cylinder 20
The inside is almost in a vacuum state, creating a significant difference in pressure from the pressure inside the receiver tank 40.

On the other hand, a partition plate 45 and a separator 42 are provided in the receiver tank 40 to separate the lubricating oil contained in the compressed gas, and the lubricating oil sent into the receiver tank 40 is separated from the compressed gas by gravity. Most of it is separated and flows down to a reservoir 65 formed by the space on the right side of the partition plate 45 in the receiver tank 40 in FIG. 1, where it is deposited. A small amount of mist-like oil that remains without being separated from the compressed gas passes through the separator 42 and is separated from the compressed gas, and the lubricating oil separated there is passed through the separator 42 and the piping 46 that supplies the compressed gas to the outside. The oil infiltrates into an oil sump 50 which is a space formed on the left side of the separator 42 in FIG. 1 between the side walls of the receiver tank 40 whose ends are connected. . In order to prevent the separation effect of the separator 42 from deteriorating due to the oil that has infiltrated and deposited in the oil sump 50, the lubricating oil that has been deposited near the bottom of the oil sump 50, where the oil is deposited, is While connecting one end of the recovery pipe 44,
Via the electromagnetic valve 60, the other end of the compression chamber is located on the discharge side of the injection port of the casing 20' and does not communicate with the discharge port 38, in the illustrated embodiment, the discharge port 38.
A recovery hole 61 (first
(Figure). In other words, this compression chamber is a working space in which the pressure is lower than the pressure in the oil sump 50 and within a pressure range in which the compressed gas in the lubricating oil does not expand again and increase the load power of the compressor. corresponds to

When the pressure in the receiver tank is above a certain value, that is, during no-load operation, the unloader 10 is blocked, and the flow of compressed gas in the receiver tank is stopped, and the oil separation action by the separator is also stopped. The solenoid valve 60 is closed to prevent compressed gas from being unnecessarily supplied into the cylinder, and the solenoid valve 60 is opened when the pressure in the receiver tank is below a certain value, that is, during load operation. The oil separated by the separator and deposited below the oil sump 50 is recovered into the compression chamber using a pressure difference.

In the embodiment of the present invention, the recovery piping 44 having the electromagnetic valve 60 for recovering the oil separated by the separator into the cylinder of the compressor is connected to the inside of the cylinder of the compressor and the receiver tank at the same time as the compressor is stopped. It is used as a pressure equalizing passage.

That is, the solenoid valve 60 is of a closed type when energized,
By connecting to the A contact side of the pressure switch 43, the solenoid valve 60 is opened at the same time as the compressor is stopped, and the receiver tank and cylinder are compressed without impairing the action of the solenoid valve 60 during no-load operation or load operation. The solenoid valve 60 is closed when energized and is connected to the A contact side of the pressure switch 43. connect in series,
Similarly, a solenoid valve 11 leading to the unloader 10 is closed when energized and is connected in series to the B contact side of the pressure switch 43.

That is, as shown in FIG. 2, the pressure switch 43 is connected between the lines l and l' connected to the power source E.
A series circuit consisting of the A contact of the pressure switch 43, a series circuit consisting of the solenoid valve 60, a B contact of the pressure switch 43, a series circuit consisting of the solenoid valve 11, a relay M that opens and closes the contacts of the compressor drive motor (not shown), and a self-holding contact Xa that opens and closes it. Relays X are connected in parallel, and the contacts are connected between lines L.
Compressor start switch PB− connected in parallel with Xa
Connect L and compressor stop switch PB-S in series.

When start switch PB-L is pressed, relay Driven. When the pressure in the receiver tank 40 is below a certain value, the pressure switch 43 is in the position shown in FIG. 2, contact A is OFF, contact B is ON, and the solenoid valve 11 is energized and closed. On the other hand, the solenoid valve 60 is open because it is not energized. Therefore, the oil reservoir portion 50 of the separator separated by the separator 42
The oil deposited in the compressor is recovered into the cylinder of the compressor via the recovery piping 44. When the amount of compressed gas used decreases and the internal pressure of the receiver tank rises to a certain level, the pressure switch 43 is activated, and its contact A is turned ON and its contact B is turned OFF. Therefore, the solenoid valve 11 is de-energized, the solenoid valve 11 is opened, and as described above, the receiver tank internal pressure is supplied to the primary side diaphragm chamber of the unloader 10 through the piping 12, presses the diaphragm 13, and the unloader 1
0 closes the intake air and the compressor shifts to no-load operation. At this time, the solenoid valve 60 is closed by turning on the contact A of the pressure switch 43. On the other hand, oil amount adjustment valve 29
In conjunction with the electromagnetic valve 11, the oil passage is narrowed to reduce the flow rate. Further, since the check valve 39 is closed due to the intake blockage of the unloader 10, the inside of the discharge port 38 is cut off from the piping leading to the receiver tank, and the inside of the working space becomes negative pressure. At this time, the compressed fluid in the gas-liquid mixed state of compressed gas and lubricating oil remaining in the discharge port is recovered to the receiver tank by the suction action of the pump 25, so that the pressure in the discharge port is rapidly reduced and the pressure in the discharge port is reduced. Back pressure acting on the compressor rotor is also removed. As a result, no-load operation continues with the compression space of the cylinder in a nearly vacuum state.

If the compressor is stopped in this condition,
As mentioned above, the negative pressure in the working space causes the reservoir 65 to flow from the injection port 27 communicating with the compression chamber in the middle of compressing the intake gas of the cylinder via one pump 24 provided at the shaft end of the rotor 21. This results in a large amount of lubricant being pumped.

In the present invention, next, the stop switch PB
- When S is pressed, relays X and M and solenoid valves 11 and 60 are all de-energized, the compressor is stopped, and solenoid valve 11 remains open because it is de-energized, while solenoid valve 60 is de-energized. is also de-energized and becomes open. Therefore, the high-pressure compressed gas in the receiver tank 40 is supplied through the recovery pipe 44 into the working space of the cylinder 20, which is in a negative pressure state, and as a result, the pressure in the cylinder increases rapidly and the pressure in the receiver tank 40 increases. It will be the same as the pressure. Therefore, lubricating oil is prevented from flowing into the cylinder 20 from the pipe connecting the reservoir 65 of the receiver tank 40 and the injection port 27 provided in the casing 20'.

Reference numeral 62 designates a solenoid valve, which, like the solenoid valve 11 leading to the unloader 10, is of the type that opens when energized, and is therefore opened by the stop switch PB-SOFF to gradually release the high pressure gas in the receiver tank to the atmosphere.

Note that the present invention is not limited to the above embodiments, and the structure of the receiver tank and separator may be any known structure as long as it does not impair the above-mentioned effects of the present invention. Needless to say. Furthermore, the present invention is not limited to the screw rotary compressor mentioned above, but is also applicable to compressors provided on the outer periphery of the rotor, as shown in, for example, Japanese Utility Model Publication No. 42-13732, Japanese Utility Model Publication No. 55-22227, and Japanese Unexamined Patent Publication No. 55-43211. A vane type with a vane in the rotor groove, and a worm type oil-cooled type with a worm on the outer periphery of the rotor, as shown in Japanese Patent Application Laid-Open No. 72206/1983, Japanese Utility Model Publication No. 52-6884, Japanese Utility Model Publication No. 56-53102, etc. In rotary compressors, worm type,
Other oil-cooled rotary compressors, including vane-type rotary compressors, have substantially the same overall structure except for the specific means for forming compression chambers, and therefore are similar to the invention of the present invention. potential technical challenges,
It is possible to apply the present invention to such other types of oil-cooled rotary compressors to obtain the functions and effects of the present invention.

〔effect〕

As described above, according to the present invention, the piping for introducing compressed gas into the compression chamber of the cylinder is connected to the lubricating oil reservoir of the receiver tank for lubricating, sealing, and cooling the compression chamber and the compression chamber of the cylinder. A pipe is provided separately from the lubricating oil supply pipe that communicates with the cylinder to collect the separated oil deposited in the oil sump in the receiver tank, and the pipe is connected to the cylinder from the oil sump in the receiver tank. It communicates with a compression chamber located on the discharge side of the injection port and not in communication with the discharge port. That is, the compressed gas is introduced into the compression chamber of the cylinder at the same time as the compressor is stopped, and the internal pressure of the cylinder is immediately increased to immediately block the lubricating oil flowing from the injection port.

Therefore, this prevents a large amount of lubricating oil from flowing into the cylinder from the receiver tank, which conventionally occurs when the compressor is stopped from no-load operation, thereby preventing oil lock at the next startup and preventing compressor failure. This eliminates the problem and enables smooth starting operation.

Further, it is possible to minimize the inflow of lubricating oil from the receiver tank into the cylinder after the engine is stopped, and it is also possible to avoid the reversal phenomenon of the compressor that occurs instantaneously when the engine is stopped. If I may add,
The amount of oil in the cylinder when the machine is stopped is approximately 20% by actual measurement.
It decreased by just over % (3 at 37KW → 0.58). In this way, the occurrence of failures due to oil lock is completely prevented, and the power consumption saving mechanism is made even more effective.
It can be said that it is extremely effective.

Furthermore, the present invention utilizes the conventional path for collecting oil separated by a separator into the cylinder as a pressure equalizing path that maintains the same pressure in the cylinder and receiver tank when the compressor is stopped. Its structure is extremely simple, and its practical effects can be said to be great.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 shows a screw compressor implementing the present invention, and FIG. 2 shows an example of the sequence of the present invention. 10...Unloader, 20...Cylinder, 2
1... Screw rotor, 24, 25... Pump,
26... Suction port, 38... Discharge port, 39... Check valve, 40... Receiver tank, 42... Separator, 45... Partition plate, 43... Pressure switch, 4
4...Recovery piping, 46...Piping, 50...Oil reservoir section, 60...Solenoid valve, 65...Storage section, PB-S
...Compressor stop switch.

Claims (1)

[Claims for Utility Model Registration] A receiver tank is provided with an unloader at the suction port and a check valve at the discharge port, the receiver tank is connected to the discharge port via the check valve, and the inside of the receiver tank is divided by a separator. The portions before and after the compressed gas passes through the separator are divided into a lubricating oil reservoir and an oil reservoir, respectively, and the reservoir is used during compression of the gas taken into the cylinder through a pump provided at the end of the rotor shaft. The reservoir section is connected via piping to an injection port opening into a compression chamber, and the reservoir section is connected via piping to the discharge port via another pump provided at the end of the rotor shaft. In an oil-cooled rotary compressor that stops operation after a no-load operation that is blocked by a valve, a solenoid valve is installed in a compression chamber in which the oil reservoir is located on the discharge side of the injection port and does not communicate with the discharge port. via a pressure switch attached to the receiver tank and a compressor stop switch, so that the solenoid valve is opened during load operation and at the same time as the compressor is stopped, and closed when transitioning to no-load operation. An oil-cooled rotary compressor characterized by being connected to a power source.