JPS6347672Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention connects a drain container that stores drainage (moisture) generated in an oil separation tank to the oil separation tank, and when the drainage in the drain container reaches a predetermined liquid level. This invention relates to an oil-cooled rotary compressor that automatically discharges condensate.

Generally, this type of oil-cooled rotary compressor includes a compressor body that compresses gas while being cooled by oil, a power source that drives the compressor body, and a reservoir for storing oil to be supplied to the compressor body. For example, a screw type air compressor or a vane type air compressor is known, which comprises an oil separation tank for separating oil from a mixture of compressed gas and oil discharged from the main body. This type of compressor uses oil sucked in with the air to be compressed to lubricate the compressor body.
The compressed air discharged from the compressor body to the oil separation tank is supplied to the air tank after the oil is separated, and since the separated oil is at a high temperature due to the heat of compression, it is cooled. After
The structure is such that the water is supplied to the compressor body again.

On the other hand, since the compressor main body compresses external humid air, the mixture of compressed air and oil discharged from the compressor main body becomes hot and humid. For this reason, when the oil separation tank and the oil inside it are cold, such as immediately after the start of operation, the compressed air comes into contact with the oil and is cooled, causing drainage to occur in the oil separation tank and causing the oil to cool down quickly. This may cause deterioration or rust formation inside the tank. In addition, even if the oil temperature rises to the point where no condensate is generated due to continuous load operation, when the pressure inside the air tank reaches the maximum, this will be detected and the rotation of the power source such as the motor will be stopped. Stop driving. As a result, the oil temperature in the oil separation tank decreases due to natural heat radiation, and drainage occurs.

Therefore, in the conventional technology, for example,
As shown in Publication No. 107992, there is a drain container installed at the bottom of an oil separation tank, and a device installed inside the drain container that calculates the intermediate specific gravity between the drain and oil in order to detect when the drain reaches a predetermined liquid level. a float-type drain detector comprising a float and a reed switch operated by the float; and a float-type drain detector provided on the discharge side of the drain container, which opens a valve to discharge the drain when the drain detector detects a drain liquid level. An automatic drain discharge device is known which consists of a normally closed solenoid valve. When condensate is generated in the oil separation tank, the condensate accumulates in a layer below the oil and the oil level rises, and this condensate flows into the drain container and the liquid level of the condensate in the drain container also increases. As a result, the float type drain detector detects this, opens the solenoid valve, and automatically discharges the drain.

However, in the conventional technology described above, even when the compressor main body is being driven,
When the drain liquid level reaches a predetermined height, the drain detector detects this and opens the solenoid valve. In this way, when the solenoid valve opens while the compressor body is operating,
Although the mixture of compressed air and oil discharged from the compressor body stirs the oil and condensate in the oil separation tank and forms an emulsion, the emulsion of condensate and oil are mixed. and will flow together into the drain container. As a result, the float, which has a specific gravity between that of the oil and the drain, floats in the emulsion of the drain, causing a malfunction, causing the electromagnetic valve to open again and draining the oil to the outside. In addition, since a large amount of oil leaks into the drain container along with the drain, the oil in the oil separation tank decreases, reducing the lubrication and cooling functions of the compressor body, and there is a risk of burning out the compressor body. . Furthermore, if the solenoid valve opens during compression operation of the compressor main body, the pressure inside the oil separation tank is high, so condensate and oil forcefully squirt out from the drain exhaust port, causing the oil to flow out. There were flaws.

The present invention was developed in view of the problems of the conventional technology, and it replaces the oil in the oil separation tank with the drain after the compressor main body stops operating, thereby preventing oil from flowing out. An object of the present invention is to provide an oil-cooled rotary compressor that can

In order to achieve this objective, the present invention provides a compressor body that compresses gas while being cooled by oil, a power source that drives the compressor body, and a power source that stores and supplies oil to the compressor body. an oil separation tank that separates oil from a mixture of compressed gas and oil discharged from the main body; a drain container that is connected to the oil separation tank and stores the drain generated in the oil separation tank; a drain detector provided on the outflow side of the drain container to detect when the drain reaches a predetermined liquid level; and a normally closed valve that opens when the drain detector detects the drain liquid level. In an oil-cooled rotary compressor comprising a valve and another on-off valve provided between the oil separation tank and the drain container, the other on-off valve is driven by a power source of the compressor main body. The invention is characterized in that it is configured as a normally open on-off valve that is closed during periods when the power source is stopped and opened when the power source is stopped.

With this configuration, the other on-off valves automatically open after the power source stops, so the drain generated in the oil separation tank is replaced with the oil in the drain container after the power source stops. This can prevent oil from flowing out together with emulsion-formed condensate during compression operation.

The present invention will be described below along with embodiments shown in the drawings.

In the figure, reference numeral 1 indicates a compressor body that compresses air while being cooled by oil.The compressor body 1 uses, for example, a screw rotor consisting of male and female rotors that mesh with each other, and the compressor body 1 is a power source. It is driven by a motor 2 as shown in FIG. A suction filter 5 is provided in a suction pipe 3 connected to the suction side of the compressor body 1 via a check valve 4 . A discharge pipe 6 connected to the discharge side of the compressor main body 1 is connected to an oil separation tank 7, and discharges a mixture of compressed air and oil from the compressor main body 1. Here, the oil separation tank 7 stores oil 8 therein, and is also equipped with an oil separator 9 that separates oil from the aforementioned mixture of compressed air and oil. 10 is an air pipe that supplies the compressed air purified by the oil separator 9 to the air tank 11, and in the middle of the air pipe 10 is a pressure holding valve 12 that maintains the inside of the oil separation tank 7 at a predetermined pressure or higher;
A check valve 13 is provided. In the figure, reference numeral 14 denotes a normally closed pressure switch, which opens when the internal pressure of the air tank 11 reaches a predetermined maximum pressure, and closes when the pressure within the air tank 11 reaches a predetermined minimum pressure. 15 is motor 2
Indicates the main switch for starting and stopping the
It has a circuit configuration that will be described later.

Reference numeral 16 denotes an oil pipe for supplying oil in the oil separation tank 7 to the compressor main body 1. One end of the oil pipe 16 opens at the bottom of the oil separation tank 7, and the other end opens at the bottom of the compressor main body 1. Connected to the suction side. A temperature control valve 17, an oil cooler 18, and a filter 19 are provided in the middle of the oil pipe 16 to detect the oil temperature and switch the flow path, and a branch pipe 20 has one end connected to the temperature control valve 17. The other end is oil cooler 1
When the oil temperature is low, the temperature control valve 17 detects this and flows the oil to the branch pipe 20 side without using the oil cooler 18. On the other hand, an oil return pipe 21 is provided between the oil separator 9 and the suction side of the compressor body 1 to return the oil separated by the oil separator 9. The above configuration is no different from that of the prior art.

Next, 22 is a drain pipe for discharging the drain generated in the oil separation tank 7. One end of the drain pipe 22 is opened at the bottom of the oil separation tank 7, and the other end is opened at the upper position of the drain container 23. ing. A solenoid 24 is located in the middle of the drain pipe 22.
A normally open solenoid valve 24 operated by A is inserted, and the solenoid valve 24 is closed when the compressor main body 1 is performing compression operation as described later, and when the compressor main body 1 is performing compression operation. The valve is configured to open when the engine stops.

Further, a drain detector 25 is provided at the middle part in the height direction of the drain container 23, and in this embodiment, the drain detector 25 is configured as, for example, a coaxial cylindrical capacitance sensor, and has an inner tube and an outer tube. A predetermined interelectrode capacitance is formed by the presence of drain or oil between the electrodes. Here, since the dielectric constant of water is 30 to 40 times larger than that of oil, the liquid level detection circuit is configured with a bridge circuit or a resonant circuit that includes the interelectrode capacitance. The drain liquid level can be detected by bringing the drain detector 25 into an equilibrium state with the bridge circuit due to the capacitance when immersed in the drain, or by bringing the resonance circuit into a resonant state. On the other hand, the drain container 23
A drain discharge pipe 26 is connected to the bottom of the drain pipe 26, and a normally closed solenoid valve 27 operated by a solenoid 27A is provided in the middle of the discharge pipe 26.

Furthermore, FIG. 2 is an electric circuit diagram used in the compressor shown in FIG. , a series circuit consisting of the solenoid 27A of the solenoid valve 27, a normally open relay contact R-1, a series circuit consisting of the magnetic switch MS, and a normally open relay contact R.
-2 and a series circuit consisting of the solenoid 24A of the electromagnetic valve 24 are respectively connected. On the other hand, a magnetic switch is connected between AC power supply E and motor 2.
MS normally open contact MS-1 is inserted.

The present invention is constructed as described above, and its operation will be described next.

First, in the state before operation, the solenoid valve 24 is open, the inside of the drain container 23 is separated into an oil layer A and a drain layer B, and the drain layer B is lower than the drain detector 25, and the solenoid valve 27 is closed. Moreover, no drain remains in the oil separation tank 7.

In this state, when main switch 15 is turned on, relay R is energized and its contacts R-1 and R-2
is closed, and the closing of the contact R-1 excites the magnetic switch MS, which closes the contact MS-1, starts the motor 2, and the closing of the contact R-2 turns on the solenoid 24A. Energized solenoid valve 24
is closed and the drain pipe 22 is cut off.

When the compressor main body 1 rotates by starting the motor 2, the suction side of the compressor main body 1 becomes negative pressure, and external air is sucked in through the suction filter 5, suction pipe 3, and check valve 4, and the oil pipe 16 , the oil in the oil separation tank 7 is sucked in through the temperature control valve 17, the branch pipe 20, and the filter 19. The mixture of compressed air and oil pressurized by the compressor main body 1 is discharged into an oil separation tank 7 via a discharge pipe 6, and then an oil separator 9
Clean air from which oil has been separated is sent to an air tank 11 via a pressure holding valve 12 and a check valve 13. When the oil temperature in the oil separation tank 7 rises, the temperature control valve 17 detects it and switches the flow path, and the oil cooler 18
After being cooled, it is supplied to the compressor main body 1.

Note that before the compressor main body 1 is operated, the oil in the oil separation tank 7 has cooled to room temperature, so the hot and humid compressed air discharged from the compressor main body 1 is cooled by contact with the oil 8, and water vapor is removed. is condensed to become drain, and the oil and drain are mixed to form an emulsion, which is then injected into the compressor body 1 again. However, the inside of the compressor main body 1 generates compression heat during the process of compressing external air, and the inside of the oil separation tank 7 gradually becomes high temperature and high pressure.
The drain injected into the tank evaporates when it comes into contact with the compressed air, and is discharged into the oil separation tank 7 as compressed air, oil, and drain vapor, and even when it comes into contact with the oil 8, the drain vapor does not condense. As a result, only the oil is removed by the oil separator 9 in the oil separation tank 7, and the compressed air and condensate vapor are led to the air tank 11 through the oil separator 9, and the condensate gradually decreases. No drainage occurs during rated operation. Therefore, even if the solenoid valve 24 is closed during compression operation of the compressor main body 1, there will be no problem.

However, when the air tank 11 reaches a predetermined maximum pressure and the pressure switch 14 is opened, or when the main switch 15 is opened at the end of the work, the relay R is demagnetized and its contacts R-1 and R-2 are opened. is opened, the motor 2 is stopped, and the solenoid valve 24 is opened. When the compressor main body 1 stops compression operation by stopping the motor 2, the oil separation tank 7 and the oil 8 are cooled by natural heat radiation, and drainage is generated in the oil separation tank 7. This drain becomes the lower layer of the oil 8 due to the difference in specific gravity, and flows into the drain container 23 via the drain pipe 22 and the electromagnetic valve 24.

Here, the inside of the drain container 23 is separated into an oil layer A and a drain layer B, but as described above, the drain container 23
The liquid level in the drain layer B rises due to the drain flowing into the tank 3, and the oil forming the oil layer A flows back into the oil separation tank 7 via the drain pipe 22 and the solenoid valve 24, and the drain layer B rises. Oil and drain are replaced within the container 23. As a result, the drain detector 25 is immersed in the drain layer B, the inter-electrode capacitance increases, and the drain liquid level is detected. Thereby, the excitation coil 27A of the electromagnetic valve 27 is energized to open the valve, and the drain in the drain container 23 can be automatically discharged via the drain discharge pipe 26.

As described above, as the drain is discharged, the oil 8 in the oil separation tank 7 gradually flows out into the drain container 23, and the oil layer A becomes larger and the drain layer B decreases again. When the drain detector 25 is completely immersed in the oil layer A as shown in FIG. stop. As a result, all of the drain in the oil separation tank 7 will be discharged.

Next, FIG. 3 shows another embodiment of the present invention, and the feature of this embodiment is that an air release valve 31 is provided in the oil separation tank 7, and the air release valve 31 is operated by the compressor main body 1 for compression operation. The valve is closed when the compressor body 1 is in the compressor state, and opened when the compressor main body 1 stops compressing operation. That is, the air release valve 31 is controlled by the relay contact R-2 so as to perform the same operation as the on-off valve 24, and is configured as a solenoid valve.

With this configuration, when the on-off valve 24 opens, the release valve 31 also opens, and the compressed air remaining in the oil separation tank 7 is immediately released into the atmosphere. When the drain liquid level is detected and the on-off valve 27 is opened, the oil separation tank 7
It is possible to reliably prevent an accident in which the oil flows out into the drain container 23 due to the internal pressure and the drain and oil are spouted out together from the drain discharge pipe 26. Further, when the on-off valve 27 is opened, oil can be prevented from flowing into the drain container 23 and forming an emulsion state, thereby increasing the detection accuracy of the drain detector 25 and preventing oil spill accidents. In this case, if the air release valve 31 is opened and the opening/closing valve 24 is opened after a predetermined period of time has elapsed, the above-mentioned effects will be even greater.

Although the embodiment of the present invention has been described as using electromagnetic valves 24 and 27 as the on-off valves,
It may also be an air-operated valve or a mechanically operated valve. In addition, although it has been described that a capacitive type is used as the drain detector 25, as in the conventional technology, a float having a specific gravity intermediate between that of drain and oil, and a lead operated by the vertical movement of the float are used. Alternatively, the drain detector 25 may be a mechanical float, and the electromagnetic valve 27 may be a mechanical on-off valve that operates in conjunction with the mechanical float. Further, in order to open the solenoid valve 24 after drainage is generated in the oil separation tank 7, the solenoid valve 24 may be demagnetized after a predetermined period of time has passed after the motor 2 stops driving. In this case, a circuit configuration in which a timer is inserted between relay contact R-2 and solenoid 24A in FIG. And it is sufficient.

The oil-cooled rotary compressor according to the present invention is as described in detail above, and the other on-off valve provided between the oil separation tank and the drain container is closed while the power source is driving. Since the valve is set to be a normally open on-off valve that is open while the power source is stopped, when the drain in the drain container reaches a predetermined liquid level during compression operation, the drain detector detects the drain liquid level. Even if one opening/closing valve is detected and opened, the other opening/closing valves will not open during compression operation, and as in the prior art, emulsion-formed condensate flows into the drain container and is detected by the condensate detector. It is possible to reliably prevent an accident in which the system malfunctions and oil is discharged to the outside along with the drain. In addition, since the oil layer and the drain layer are replaced in the drain container by the drain generated in the oil separation tank after the power source is stopped, the entire amount of drain in the oil separation tank must be automatically discharged. I can do it. This not only prevents condensate from remaining in the oil separation tank and causing rust or hastening oil deterioration, but also prevents oil from leaking out during compression operation and causing burnout of the compressor body. This has many effects, such as preventing accidents such as accidental accidents.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an oil-fed rotary compressor according to the present invention, Fig. 2 is an electric circuit diagram used in the compressor of Fig. 1, and Fig. 3 is an illustration of an oil-fed rotary compressor according to the present invention. FIG. 2 is an overall configuration diagram showing an embodiment of the present invention. 1...Compressor main body, 2...Motor (power source),
7... Separation tank, 8... Oil, 11... Tank,
16...Oil pipe, 22...Drain pipe, 23...
Drain container, 24, 27...Solenoid valve (on/off valve),
25...Drain detector.

Claims (1)

[Scope of utility model registration request] A compressor body that compresses gas while being cooled by oil; a power source that drives the compressor body; and a mixture of compressed gas and oil that stores oil to be supplied to the compressor body and is discharged from the compressor body. an oil separation tank that separates oil from the body; a drain container that is connected to the oil separation tank and stores the drain generated in the oil separation tank; a drain detector for detection, a normally closed on-off valve that is provided on the outflow side of the drain container and opens when the drain detector detects a drain liquid level, and a connection between the oil separation tank and the drain container. In an oil-cooled rotary compressor comprising another on-off valve provided in between, the other on-off valve is closed while the power source of the compressor main body is driving, and when the power source is stopped. An oil-cooled rotary compressor characterized in that it is configured as a normally open on-off valve that is open while the valve is in use.