JPS6365836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-cooled compressor that detects the pressure of compressed air in an air tank system and controls a suction throttle valve provided on the air suction side of the compressor main body.

Generally, in oil-cooled compressors such as screw type compressors and slide vane type compressors, lubricating oil is circulated between the compressor body and an oil separator to both lubricate and cool the compressor body. There is.

Conventionally, this type of oil-cooled compressor consists of a compressor body that compresses air while being supplied with lubricating oil, an oil separator that separates oil from the compressed air discharged from the compressor body, and an oil separator that separates oil from the compressed air discharged from the compressor body. An air tank that is connected to the oil separator via a check valve and stores the compressed air supplied from the oil separator, and an air tank that is installed on the air suction side of the compressor body and that closes the suction port during no-load operation. a suction throttle valve to be operated, a communication pipe connecting the oil separator and the suction throttle valve, and a predetermined pipe provided in the middle of the communication pipe to detect compressed air in the air tank system and perform no-load operation. A pressure regulating valve that opens when a high pressure is reached and closes when a predetermined low pressure at which load operation should be started is known.

With this configuration, when the inside of the air tank reaches a predetermined pressure for no-load operation, the pressure regulating valve opens and the compressed air in the oil separator is caused to act on the suction throttle valve from the communication pipe, The suction throttle valve is closed to reduce the amount of suction air to reduce power, and to prevent lubricating oil from flowing backwards and spewing out from the suction port.

However, the conventional technology configured in this manner has the following problems.

First, when the suction throttle valve is completely closed during no-load operation, the suction side of the compressor body becomes a vacuum state, and the differential pressure between the suction side and the discharge side becomes large, causing a backlash against the screw rotor end surface. The pressure acts intermittently, causing uneven rotation of the rotor during operation, causing the rotor to generate abnormal vibrations and causing unloading noise. In order to prevent this noise, a bypass valve is installed that detects the degree of vacuum on the suction side of the compressor body and opens, and when the bypass valve opens, the compressed air in the tank or oil separator is circulated, or the suction A method has been proposed in which the suction throttle valve on the side does not close completely, and a method in which a throttle passage that is always in communication is provided in parallel with the suction throttle valve.

However, the first method with a bypass valve has the disadvantage of complicating the piping system, and with the method that does not completely close the latter two suction throttle valves or the method that provides a throttle passage, the power reduction is only 25% of the rated value. It only reached ~30%, and there was a risk that the lubricating oil would flow back when the operation was stopped.

Second, in order to automatically release the pressure inside the oil separation tank at the same time as the suction throttle valve is closed, the oil separator is equipped with a release valve, and the release valve is opened during no-load operation. A structure is known in which the pressure inside the oil separator is lowered to reduce the no-load power (Utility Model Publication No. 57704/1983).

However, this configuration requires a separate air release valve and an air silencer to prevent noise when air is released, which not only increases the number of parts but also complicates the configuration. There is a drawback that. In particular, as shown in the above-mentioned Japanese Utility Model Publication No. 48-57704, when compressed air from which oil has not been removed by an oil separator is directly released into the atmosphere from a release valve, the released air contains The disadvantage is that the oil mist contained therein dissipates into the atmosphere and contaminates the inside of the soundproof box surrounding the compressor.

The present invention has been developed in view of the shortcomings of the prior art.The present invention has been developed to provide the suction throttle valve not only with its original blocking valve function, but also with a recirculation function that allows part of the compressed air to flow back to the suction side of the compressor body during no-load operation. To provide an oil-cooled compressor which is configured to have an air release function for reducing no-load power during no-load operation, and whose suction throttle valve is controlled using compressed air in an air tank. The purpose is to

To achieve this objective, the present invention includes a compressor body that compresses air while being supplied with lubricating oil;
An oil separator that removes oil from the compressed air discharged from the compressor body; and an oil separator that is connected to the oil separator via a check valve and stores normal compressed air supplied from the oil separator. an air tank, a suction throttle valve provided on the air suction side of the compressor main body, an air discharge pipe connecting between the oil separator and the suction throttle valve, and an air discharge pipe provided in the middle of the air discharge pipe, and a control valve mechanism that detects the pressure in the system including the air tank and opens the valve when the pressure reaches a predetermined high pressure, and closes the valve when the pressure drops to a predetermined low pressure, and the suction throttle valve opens to the atmosphere. a valve body having an intake port connected to the compressor body, a discharge port connected to the compressor body, and a supply port connected to the air discharge pipe; and a valve body provided within the valve body biased to close the intake port. , a check valve that opens due to a pressure difference between the intake port and the discharge port, and a check valve that is provided within the valve body coaxially with the check valve and biased in the valve closing direction. , while the control valve mechanism is open, the valve is opened by compressed air in the oil separator supplied from the supply port, and the check valve is pushed closed to allow no-load operation. a valve, and is formed in the valve body or in the axial direction of the check valve and the main valve, and discharges compressed air in the oil separator supplied from the supply port when the main valve opens. a relief passage that allows the air to flow back to the port; a discharge passage formed within the valve body that causes the compressed air in the oil separator supplied from the supply port to be released to the intake port side; The valve body includes a throttle mechanism provided on the valve body to adjust the air flow rate.

With this configuration, when the inside of the air tank reaches a predetermined high pressure required for no-load operation, the control valve mechanism opens and clean air flows through the exhaust pipe and control valve mechanism to the suction throttle valve. supplied to the supply port. This opens the main valve, pushes the check valve, closes the intake port, and performs a blockage valve function.
Furthermore, when the main valve opens, the compressed air supplied from the supply port is circulated from the discharge port to the suction side of the compressor main body via the relief passage, thereby exerting a recirculation function. Further, the compressed air in the oil separator supplied from the supply port is released to the intake port via the release passage, and exhibits an air release function that reduces no-load power.

This will be explained below along with embodiments shown in the drawings. FIG. 1 is a system diagram showing a first embodiment of the present invention. In the figure, 1 indicates a compressor main body, and the main body 1 is, for example, a screw type rotor or a slide vane type equipped with mutually meshing male and female rotors. A rotor is used, and the compressor body 1 is driven by a motor 2. A suction throttle valve 4 shown in FIG. 2 is provided in the middle of an intake side pipe 3 provided in the compressor body 1, and a suction filter 5 is provided on the suction side of the suction throttle valve 4. An oil separator 7 is connected to the discharge side pipe 6 provided in the compressor main body 1, and the oil separator 7 includes a mist separator for separating oil from the compressed air pumped together with lubricating oil, which will be described later. 8 is provided, and the compressed air purified by the separator 8 is maintained at a predetermined pressure or higher by a pressure holding valve 10 provided in the air pipe 9 and is supplied to the air tank 12 via the check valve 11. . The air tank 12 is provided with a supply air pipe 13, and the compressed air stored in the air tank 12 is supplied to the equipment in use via a stop valve 14 provided in the middle thereof.

Reference numeral 15 denotes a discharge pipe provided between the air pipe 9 and the suction throttle valve 4; a solenoid valve 16 is provided in the middle of the discharge pipe 15;
It is configured to be operated by a pressure switch 18 connected to a bypass pipe 17 branched from 3. Here, the pressure switch 18 has a contact that closes when the air pressure in the bypass pipe 17 reaches a predetermined set pressure, and opens at a return pressure lower than the set pressure, and while the contact is closed, an electromagnetic It opens the valve 16, and the solenoid valve 16 and pressure switch 18 constitute a control valve mechanism. In addition, solenoid valve 1
The valve 6 is configured to open when the rotation of the motor 2 stops, that is, when the compressor main body 1 stops operating. After the compressor main body 1 stops, the pressurized air and lubricating oil are cooled, and a drain is formed in the oil separator 7. Efforts are being made to prevent this from occurring. In the embodiment shown in FIG. 1, the pressure switch 18 is configured to detect the pressure in the air discharge pipe 17 via the bypass pipe 17, but it is activated by detecting the air pressure in the air tank 12. In short, the pressure within the system including the air tank 12 may be used.

In addition, the oil pipe 1 extending from the oil liquid of the oil separator 7
9 is connected to the suction side of the compressor main body 1, and an oil cooler 20 is provided in the middle of the oil pipe 19, and the oil cooler 20 is connected to a multi-blade fan 2 rotated by a motor 2.
1. Further, an oil pipe 22 for recovering separated oil is provided between the mist separator 8 and the compressor main body 1. 2
3 is a stop valve for drain and oil removal.

Next, FIG. 2 shows a vertical cross-sectional view of the suction throttle valve 4 shown in FIG. Consists of three members, with a spring receiver 24A in the center.
is formed. The valve body 24 is connected to an intake port 25 connected to the suction filter 5, a discharge port 26 connected to the suction side of the compressor body 1 via the suction side piping 3, and an oil separator 7 via the discharge piping 15. It has a supply port 27 to which it is connected. Further, a check valve 28 is provided between the intake port 25 and the discharge port 26 of the valve body 24, and a main valve 29 is provided coaxially with the check valve 28. Both are guided by the spring receiving portion 24A. The check valve 28 has a spring 30 stretched between the spring receiving portion 24A and the check valve 28, so that the main body 28A is always held against the valve seat 3.
1, and divides the passage into chamber A on the intake port side and chamber B on the discharge port side. B
(The check valve 28 is shown in an open state due to the pressure difference with the vacuum pressure on the side.) On the other hand, in the main valve 29, the valve body 29A is always in contact with the valve seat 33 due to the spring 32 stretched between the spring receiving part 24A and the main valve 29.
It is divided into rooms C and D. A chamber E is formed between the main valve 29 and the spring receiving portion 24A, and the chamber E is constantly in communication with the chamber B via the passage 34.

Further, a discharge passage 35 is formed in the valve body 24 , one end of the discharge passage 35 opens to the supply port 27 , and the other end opens to the intake port 25 . Therefore, when the check valve 28 is closed and seated on the valve seat 31, all the compressed air released from the discharge passage 35 is discharged from the suction filter 5. A throttle mechanism 36 that can be screwed in and out is provided in the middle of the valve body 24, and a valve portion 36A of the throttle mechanism 36 is provided.
protrudes into the discharge passage 35, and the passage area of the discharge passage 35 is configured to be adjustable. When removing oil from the oil separator 7 by the action described later, the valve portion 36A of the throttling mechanism 36 is closed. It is configured so that it can be brought into contact with the seat 37 and the discharge passage 35 can be completely closed.

Further, a main valve inflow side passage 38 is formed between the supply port 27 and the chamber C, and another throttle mechanism 39 that can be screwed in and out is provided in the valve body 24, and the valve portion 39A of the throttle mechanism 39 is It protrudes into the main valve inlet side passage 38, and the passage area of the passage 38 can be adjusted, and when all the compressed air in the oil separator 7 is released by the action described later, the valve portion 369 is moved to the valve seat. 40
It is configured so that it can be brought into contact with the

Further, a relief passage 41A is formed along the axis of the check valve 28, and a relief passage 4 is formed coaxially with the relief passage 41A along the axis of the main valve 29.
1B is formed (relief passages 41A, 4
1B as a whole is referred to as a relief passage 41).
One end of the relief passage 41 opens into the chamber B, and the other end opens into the chamber D. Therefore,
When the main valve 29 is open, the air released from the supply port 27 flows through the passage 38, the chambers C, D,
It can be circulated to the intake side of the compressor main body 1 via the relief passage 41, the chamber B, and the discharge port 26.

The first embodiment of the present invention is configured as described above, but the throttle mechanism 36 of the suction throttle valve 4 is opened prior to the operation of the compressor, and the suction filter 5 in the oil separator 7 is opened during no-load operation. Set the opening to the extent that air can be released to the side and no-load operation can be performed under the lowest power conditions. In addition, the other throttle mechanism 39 is opened and the opening degree is set to the minimum condition that allows the discharged air to circulate to the intake side so that the intake side of the compressor body 1 does not become a vacuum during no-load operation and generate unloading noise. I'll keep it. Further, the pressure switch 18 sets the internal pressure of the air tank 12 for no-load operation according to the pressure conditions of the equipment connected to the stop valve 14.

Here, when the motor 2 is started, the compressor body 1 rotates, and when the suction side of the main body 1 including the suction side piping 3 reaches a vacuum pressure, the pressure difference between the front and rear of the check valve 28 resists the spring 30 and prevents the non-return valve. The valve 28 opens and automatically adjusts the amount of suction air supplied into the compressor main body 1. The air pressurized by the compressor main body 1 is discharged into the oil separator 7 together with lubricating oil via the discharge side piping 6. After the mist is removed from the compressed air in the oil separator 7 by the mist separator 8, it is supplied to the air tank 12 via the pressure retaining valve 10 and the check valve 11. At the same time, the separated lubricating oil is sent to the oil pipe 19, It is supplied to the compressor main body 1 via the cooler 20 to lubricate and cool the rotor.

However, when the internal pressure of the bypass pipe 17, that is, the internal pressure of the air tank 12 reaches a pressure for no-load operation, the pressure switch 18 closes and the solenoid valve 16 opens. As a result, the discharged air that has reached the supply port 27 reaches the intake port 25 via the discharge passage 35 and the throttle mechanism 36, and is released into the atmosphere from the suction filter 5. The load on the main body 1 is reduced and the power of the motor 2 is reduced. Note that the air release continues until the lower limit set pressure of the pressure switch 18, that is, the closing pressure of the solenoid valve 16.

At the same time, the main valve 29 is opened against the spring 32 by the released air supplied to the chamber C via the other throttle mechanism 39 and the main valve inflow side passage 38, and the main valve 29 opens against the spring 32.
pushes the check valve 28 into contact with the valve seat 31.
As a result, the air discharged from the chamber C passes through the chamber D, the relief passage 41, and the chamber B, reaches the discharge port 26, and flows back into the compressor body 1 through the intake pipe 3, causing unloading noise from the compressor body 1. It prevents you from doing so.

On the other hand, when the operation of the compressor main body 1 is stopped, the rotor is reversed due to the residual pressure in the oil separator 7, and the main body 1
Compressed air flows back from the discharge port 26 along with the lubricating oil inside. However, since the chambers B and E are communicated through the passage 34, the main valve 29 contacts the valve seat 33 due to the backflow pressure and immediately closes, and the lubricating oil reaches the chamber D through the relief passage 41. It does not flow into chamber C either. Therefore, the residual air in the oil separator 7 is released to the atmosphere via the discharge passage 35 as described above via the electromagnetic valve 16 which opens when the compressor main body 1 stops operating.

Furthermore, when the lubricating oil in the oil separator 7 is to be drained when the compressor main body 1 is stopped, the throttle mechanism 36 is operated during the air release described above, and the valve portion 36 is operated.
By bringing A into contact with the valve seat 37 to close the valve, and then opening the stop valve 23, the residual pressure in the oil separator 7 can quickly remove the oil. Incidentally, if a locking mechanism is added to the throttle mechanism 36 and a slide type so-called knock type or rabbit type is used, the oil removal work will be further facilitated.

FIG. 3 shows another embodiment of the suction throttle valve 4 shown in FIG. 2, and the same components as in FIG. 2 are given the same reference numerals. In the embodiment shown in FIG. 2, the relief passage 41 is formed in the main valve and the check valve, respectively, whereas in this embodiment, a relief passage 42 is formed in the valve body 24. One end of 42 opens into chamber B, and the other end opens into chamber D. Therefore, although the function of the relief passage 42 is the same as that shown in FIG. 2, the suction throttle valve is easy to manufacture in that there is no need to process the main valve and check valve.

Next, FIG. 4 shows a second embodiment of the present invention, and the same components as in FIG. 1 are given the same reference numerals. In the embodiment shown in FIG. 1, a control valve mechanism is used that electrically detects the pressure of compressed air in the system of the air tank 12 and opens the solenoid valve 16, whereas in this embodiment, the system of the air tank 12 is The pressure regulating valve 50 is opened by mechanically detecting the pressure of the compressed air inside. That is, as detailed in FIG. 5, the pressure regulating valve 50 shown in FIG. Part 5
4, a spring 55 stretched between the valve body 51 and the piston 52, and a stopper 56 that locks the partition wall 54 by the spring 55. Therefore, when the internal pressure of the bypass pipe 17 exceeds a predetermined pressure, the partition 54 receives this pressure and moves the piston 52 to the right in the figure against the force of the spring 55 to open the valve. As a result, similarly to the first embodiment, the discharged air is supplied to the supply port 27 of the suction throttle valve 4, and the compressor main body 1
can perform no-load operation. In addition, the fifth
In the figure, the pressure regulating valve 50 is a piston type valve, but
The piston 52 may be replaced with a valve plug, and the partition wall portion 54 may be a flexible member, such as a diaphragm.
Although a separate air release valve may be provided, if a solenoid valve 57 is provided in parallel with the pressure regulating valve 50, which opens when the compressor main body 1 stops, as shown by the imaginary line in FIG. Since the air is released directly, no condensate is generated in the oil separator 7.

The oil-fed compressor according to the present invention is as described in detail above, and when the control valve mechanism detects the pressure of compressed air in the air tank system and opens the valve, the compressed air in the oil separator is It is supplied to the supply port of the suction throttle valve through the air discharge pipe, and opens the main valve.
The check valve is closed, the compressed air is circulated to the suction side of the compressor body through the relief passage, and the compressed air is released into the atmosphere through the discharge passage, so there is only one suction throttle valve. Due to the valve configuration, it is possible to perform three functions at the same time: a reflux function and an air release valve function in addition to a blockage valve function, and it is possible to provide individual bypass valves and throttle passages, and use air release valves and air silencers. Compared to the case where pipes are provided, not only is it easier to connect the pipes to each other, but the number of valve devices can be reduced to a minimum of one, the number of parts can be significantly reduced, and manufacturing can be done at low cost.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention;
FIG. 2 is a longitudinal sectional view of the suction throttle valve used in the present invention, FIG. 3 is a longitudinal sectional view showing another embodiment of the suction throttle valve shown in FIG. A system diagram showing an embodiment, FIG. 5 is a longitudinal sectional view of the pressure regulating valve used in FIG. 4. 1... Compressor main body, 4... Suction throttle valve, 7...
Oil separator, 10... Pressure holding valve, 12... Air tank, 16... Solenoid valve, 18... Pressure switch, 2
5...Intake port, 26...Discharge port, 27...
... Supply port, 28 ... Check valve, 29 ... Main valve,
35...Discharge passage, 36, 39...Aperture mechanism, 4
1, 42... Relief passage, 50... Pressure regulating valve.

Claims (1)

[Claims] 1. A compressor body that compresses air while being supplied with lubricating oil, an oil separator that removes oil from the compressed air discharged from the compressor body, and a An air tank connected to store clean compressed air supplied from the oil separator, a suction throttle valve provided on the air suction side of the compressor main body, and between the oil separator and the suction throttle valve. A valve is installed in the middle of the air piping to connect the air tank, and the valve opens when the pressure within the system including the air tank is detected and reaches a predetermined high pressure, and closes when the pressure drops to a predetermined low pressure. a control valve mechanism for valving, the suction throttle valve having an intake port opening to the atmosphere, a discharge port connected to the compressor main body, and a valve body having a supply port connected to the discharge piping; a check valve that is biased to close the intake port in the valve body and opens due to a pressure difference between the intake port and the discharge port; coaxially with the check valve;
and is provided in the valve body so as to be biased in the valve closing direction, and is opened by compressed air in the oil separator supplied from the supply port while the control valve mechanism is open. and a main valve for pushing the check valve closed to allow no-load operation; a relief passage that allows compressed air in the oil separator supplied from the supply port to flow back to a discharge port; and a relief passage formed in the valve body and compressed air in the oil separator supplied from the supply port. An oil-cooled compressor comprising: a discharge passage for discharging air to the intake port side; and a throttle mechanism provided on the valve body to adjust the flow rate of discharged air from the discharge passage.