JPH08135575A - Oil recovery device for oil feed type air compressor - Google Patents

Abstract

PURPOSE: To reduce oil consumption and to simplify disposal of drain by a method wherein drain in separated oil stored at an oil separator located in the delivery piping of a oil feed type air compressor is guided to an oil water separator and oil separated by an oil water separator is returned to a feed oil type air compressor. CONSTITUTION: An oil separator 3 coupled to the delivery piping 4 of an air compressor 1 separates an oil content in compressed air, separated oil is led out to the low pressure part of an air compressor 1 through an oil return pipe 5. Drain gathering at the bottom of the oil separator 3 is led out to a specific gravity type oil water separator 7. The oil water separator 7 separates oil and water in drain away from each other in a closed tank by means of a difference in specific gravity. Oil separated therein flows to the portion, situated upper stream from an oil cooler 5a, of the oil return pipe 5 through a separated oil return pipe 12 in which an orifice 13 is located. Meanwhile, water gathering at the bottom of the oil separator 7 is discharged to the outside through a drain pipe 14 in which solenoid valves 15 and 16 and an orifice 17 are located.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil recovery device for an air compressor equipped with a screw type, scroll type, rotary type or other oil supply type air compressor.

[0002]

2. Description of the Related Art In an air compressor equipped with a refueling type air compressor (a device including an air compressor and an oil separator), a large amount of oil is used for cooling, lubricating and sealing the air compressor. The compressed air in the discharge pipe of the air compressor contains dew oil. Further, since the air compressor normally sucks the air as it is, it sucks the water in the air.

Conventionally, the compressed air discharged from a refueling type air compressor passes through an oil separator having a built-in oil separation element to separate the oil from the compressed air and send the compressed air to the consumer side to separate the separated oil. Returns directly from the oil return circuit between the oil separator and the air compressor to the air compressor.

[0004]

The oil separated by the oil separator for removing the oil in the compressed air contains water. The compressed air is condensed in the oil separation tank together with the oil due to condensation of water content due to pressure and temperature drop in the discharge pipe and the oil separator.

It is also possible to recirculate these oils containing water to the air compressor as they are, but the air compressor impairs lubrication and sealing performance due to the water in the recirculated oil, resulting in a short service life.

[0006] Therefore, in order to discharge the drain accumulated as an oil emulsion at the bottom of the oil separation tank, a drain discharge device is provided to discard this drain, but the drain contains a large amount of oil components. As a result, the oil circulation amount of the air compressor is greatly reduced. Moreover, in order to discharge this drain, oil and the like in the drain must be removed, which requires equipment and running costs.

The present invention provides an oil recovery device in an oil supply type air compressor capable of extracting the drain in the oil separated in the oil separator installed in the oil supply type air compressor discharge pipe and further recovering the oil in the drain. With the goal.

With respect to the means for achieving the above-mentioned object, problems are generated in a chained manner, and these problems will be shown together with a solution in the following description.

[0009]

The first aspect of the present invention is a refueling type having an oil recirculation circuit for returning the oil separated from the oil separator interposed in the discharge pipe of the refueling type air compressor to the air compressor. In the oil recovery device of an air compressor, the drain in the separated oil accumulated in the oil separator is guided to the oil-water separator, and the oil separated into oil and water by the oil-water separator is sent from the oil-water separator to the oil circulation circuit or refueling air compression. And return it directly to the machine,
It is an oil recovery device in a refueling type air compressor, wherein separated water separated by an oil-water separator is allowed to flow out through a flow rate regulating member.

A second invention of the present invention is the oil recovery apparatus for a refueling type air compressor according to the first invention, wherein the flow regulating member is an electromagnetic valve.

A third invention of the present invention is the oil recovery apparatus for a refueling type air compressor according to the second invention, wherein the number of the solenoid valves is one.

A fourth invention of the present invention is the oil recovery apparatus for a refueling type air compressor according to the second invention, wherein a plurality of the solenoid valves are provided in series.

According to a fifth aspect of the present invention, the flow rate regulating member is an orifice and a solenoid valve, and the solenoid valve is provided in series with the orifice, and the oil in the refueling type air compressor according to the first aspect is characterized. It is a recovery device.

The sixth invention of the present invention is any one of the second to fifth inventions, characterized in that the solenoid valve is normally closed and has a control device which is opened intermittently for a required time by a timer. Is an oil recovery device in the refueling type air compressor.

According to a seventh aspect of the present invention, the oil-water separator is a closed tank, is provided with a water level detecting member for detecting the rising limit position of the water surface of the separated water, and is opened by a signal detected by the water level detecting member. It is an oil recovery device in a refueling type air compressor according to a sixth aspect of the invention, characterized in that a control device for starting timed control of the valve is provided.

According to an eighth aspect of the present invention, an oil-water separator is provided with a detecting member for detecting the upper and lower limit positions above and below the water surface of the separated water separated in a closed tank, and the electromagnetic wave is detected by the detecting member detecting the upper limit water level. The oil in the refueling type air compressor according to any one of the second to fifth inventions, characterized in that a control circuit for opening the valve and closing the electromagnetic valve in response to a signal detecting a lower limit water level is provided. It is a recovery device.

A ninth aspect of the present invention is characterized in that the water level detecting member for detecting the descent limit position of the water level is provided above the discharge port of the oil-water separator. It is an oil recovery device in an air compressor.

According to a tenth aspect of the present invention, one end communicates with the space occupied by the separated oil in the upper part of the oil-water separator, and the other end communicates with a reflux circuit or a refueling type air compressor, with a flow regulating member interposed. The oil recovery apparatus in the oil supply type air compressor according to any one of the first to ninth inventions, wherein the separated oil recirculation circuit is provided.

An eleventh invention of the present invention is characterized in that a control device of a solenoid valve interposed in an outflow passage of water separated by an oil / water separator is interlocked with an air compressor. It is an oil recovery device in any one of the air compressors.

In a twelfth aspect of the present invention, an oil-water separator is provided with a float that floats by the separated water and a water level detection member that operates when the float rises, and the float does not reach the bottom of the oil-water separation tank. An oil recovery in the air compressor according to the seventh invention, characterized in that a stopper for restricting the descending is provided, and a space for storing the separated water surface at a position higher than the drain port is provided between the float and the bottom of the tank. It is a device.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is a flow sheet.
The refueling type air compressor 1 is, for example, a screw type, a scroll type or a rotary type and needs refueling.

The air compressor 1 is connected to the output shaft of the electric motor 2 and is rotationally driven. The electric motor 2 is supplied with electric power from the power receiving side terminal UVW via a switch (see FIG. 2 SW) not shown in FIG. The suction port of the air compressor 1 is open to the atmosphere through the sound deadening filter 1b. The discharge port 1a of the air compressor 1 and the compressed air inlet 3a of the oil separator 3 are connected by a discharge pipe 4 for compressed air,
A discharge pipe 4'is connected to the compressed air outlet 3b of the oil separator 3, and the other end of the discharge pipe 4'is connected to the compressed air demand side.

The other end of the oil return pipe 5, one end of which is connected to the oil outlet 3c so as to communicate with the oil separated by the oil separator 3, communicates with the low pressure portion of the air compressor 1. However, when returning to the air compression working space above the medium pressure portion of the air compressor 1, a pump is provided in the oil return pipe 5. In the oil return pipe 5, for example, an oil cooler 5a and an oil filter 5b are provided in this order according to the flow of oil. In this way, an oil recirculation circuit is provided from the oil separator 3 to the air compressor 1.

In order to discharge the drain accumulated at the bottom of the oil separator 3, the drain outlet 3e at the bottom of the oil separator 3 and the drain inlet 7a provided in the vertical center of the specific gravity oil / water separator 7 are connected to the drain pipe 8 Tied with.

In the oil separator 3, for example, an oil separation element 3d in which glass fibers or metal strips are entwined in a non-oriented manner is provided on the upper portion. The oil separation element 3d is in the shape of a container, and the oil accumulated by the flow of compressed air inside the oil separation element 3d is joined to the oil return pipe 5 by the return oil pipe 9. The return oil pipe 9 is provided with an orifice 11. A filter is provided upstream of the orifice 11 (not shown).

The oil / water separator 7 separates oil and water in the drain in a closed tank filled with the drain by a specific gravity difference, and a separated oil outlet 7b is provided at an upper portion thereof and the separated oil outlet 7b and the oil return A separated oil return pipe 12 is provided between the pipe 5 and the pipe 5. An orifice 13 is provided in the separated oil return pipe 12.
The return position of the separated oil return pipe 12 is the oil cooler 5a.
Although it may be located between the oil filter 5b and the oil cooler 5a, or may be located downstream of the oil filter 5b,
Further, it may be a low pressure part of the air compressor 1, for example, a suction port.

A drain port 7c is provided near the bottom of the oil separator 7, and a drain pipe 14 is connected to the drain port 7c. Electromagnetic valves 15 and 16 and an orifice 17 are provided in the drain pipe 14.

In the oil / water separator 7, there is provided a float 7d which floats on water but does not float on oil or drain. The float 7d has a hollow annular shape and houses a magnet 7e in the upper portion. From the center of the bottom of the closed tank of the oil-water separator 7 to the hollow column 7
f is erected. The inside of the hollow column 7f communicates with the outside and does not communicate with the inside of the closed tank. The float 7d is attached to the hollow pillar 7f.
Is designed to be vertically movable. Hollow pillar 7
A reed switch 18, which is activated by the magnetic force of the magnet 7e in the float 7d when the float 7d rises, is provided in f. The descent of the float 7d is restricted by a stopper 7g provided upright on the bottom of the closed tank, and a little water is left at a water level higher than the drain port 7c. The drainage port 7c is located lower than the drain inlet 7a of the oil-water separator 7, and a stopper 7g secures the amount of water stored at the bottom. Therefore, even if the solenoid valves 15 and 16 are opened, the separated oil or drain is prevented from being suddenly sent into the drain pipe 14 from the drain port 7c.

A wire 22 is connected from the terminal V to the controller 21 via the reed switch 18, and a wire 23 is connected from the terminal U to the controller 21. Power lines 24 and 25 are provided from the control device 21 to the solenoid valves 15 and 16.

FIG. 2 is a diagram for explaining the operation of the above configuration.

The operation of the above configuration will be described. Power supply side terminal R
When power is supplied from the ST to the power receiving side terminal UVW by the switch SW, the electric motor 2 is energized, the air compressor 1 is operated, and the air is sucked and compressed through the muffling filter 1b to discharge the air 1a.
More compressed air is discharged, and the oil separator 3 is discharged through the discharge pipe 4.
The compressed air flows in, and the oil in the compressed air is separated by the oil separation element 3d and drip and accumulate at the bottom. Alternatively, a part of the oil is collected in the oil separating element 3d. Then, the decompressed compressed air is sent to the compressed air demand side through the discharge pipe 4 '.

The oil separated by the oil separator 3 flows out from the oil outlet 3c to the oil return pipe 5 and is cooled by the oil cooler 5a, and the oil filter 5b removes dust and solids in the oil and moves to the air compressor 1. Return.

The oil separated by the oil separator 3 contains water in the compressed air. Compressed air pressure is 10kg / cm
Water in the compressed air does not condense up to about ² and the compressed air temperature is 80 ° C or higher, but the discharge pressure of the air compressor 1 has upper and lower limits to control the on / off of the electric motor 2 or the electric motor 2 continuously rotates. However, in a refueling type air compressor in which the air compressor 1 is equipped with an unloader to turn on and off the generation of compressed air, the temperature of the compressed air in the oil separator 3 decreases while the compressed air is not sent out from the air compressor 1. Moisture in the compressed air in the oil separator 3 is condensed and mixed into the separated oil. Then, the water in the oil O accumulated in the oil separator 3 becomes a drain D in the form of an oil emulsion and accumulates at the bottom of the tank.

If left unattended, moisture will be removed from the atmosphere by the sound deadening filter 1.
Since it is supplied through b, the drain D at the bottom of the oil separator 3 gradually increases. Therefore, the oil / water separator 7 operates to always remove the drain D.

Since compressed air pressure is applied to the open liquid surface L of the separated oil O in the oil separator 3, the drain D is sent to the oil / water separator 7 through the drain pipe 8 and the oil / water separator 7
Is filled with drain D. The drain D in the oil-water separator 7 has an oil layer in the upper part and a water layer in the lower part due to the difference in specific gravity. The oil in the upper part of the oil-water separator 7 is pressurized by the compressed air pressure in the oil separator 3, so that the oil return pipe is lower in pressure than the compressed air pressure through the second separated oil return pipe 12. 5 and is joined to the first separated oil flowing in the oil return pipe 5.
It takes a time required for the drain to become oil and water in the oil / water separator 7, and the orifice 13 provided in the second separated oil return pipe 12 prevents the drain from returning to the oil return pipe 5 as the drain. Limit the flow rate of. The drain corresponding to the separated oil returned from the oil / water separator 7 by the second separated oil return pipe 12 is sequentially sent from the oil separator 3 to the oil / water separator 7 through the drain pipe 8.

Since water is separated from the drain D sent to the oil / water separator 7, the water level of the separated water at the bottom of the oil / water separator 7 gradually rises, so that the float 7d rises. Float 7
When d rises and the magnet 7e closes the reed switch 18, a voltage is applied to the control device 21 through the terminals U and V.

As shown in FIG. 2 for explaining the operation including the control device 21, when the reed switch 18 is closed, a voltage is applied to the control wiring of the control device 21 through the fuse F. A timer (hereinafter referred to as a timer) T1 is energized and an alarm lamp AL is turned on. The normally open contacts CR-1 and CR-2 are closed by the biasing of the relay coil CR of the timer T1 to close the solenoid valves 15 and 1.
6 coils SVA, SVB are excited and solenoid valves 15, 16
Opens the valve. Since the compressed air pressure has already been applied to the oil / water separator 7 through the drainage pipe 14, the flow rate is controlled by the orifice 17 so that the separated water in the oil / water separator 7 is drained. With the drainage, the water level in the oil / water separator 7 drops, the float 7d descends, and the reed switch 18 opens, but the relay coil CR of the timer T1 is held by itself, so the solenoid valves 15 and 16 subsequently open. ing. The alarm lamp AL indicates that the water is being drained. Timer T1
When the set time of 1 to 1.5 seconds has elapsed, the relay coil CR
Deenergizes, its normally open contacts CR-1, CR-2 open,
The coils SVA and SVB of the solenoid valves 15 and 16 are deenergized, the solenoid valves 15 and 16 are closed, and the alarm lamp AL is turned off.

In the above description, the flow rate is restricted by the orifice 17 and a large amount of separated water is left at the bottom of the oil / water separator 7 by the stopper 7g. Therefore, the oil or drain in the oil / water separator 7 is driven by the force of the inflowing drain. Will not be leaked. Further, since the two solenoid valves 15 and 16 are provided in series, even if one of the solenoid valves 15 and 16 bites the dust and does not close the valve sufficiently, the oil / water separator 7 is operated except when the drainage is activated. It is possible to prevent the liquid from being constantly lost. Therefore, in the case where a means for removing foreign matter in the liquid flowing into the solenoid valve, for example, a filter is provided to remove dust, and a magnet is provided to remove fine metal powder, the number of solenoid valves may be one.

In the above, the regulation of the drainage amount through the drainage pipe 14 is not limited to the orifice 17. That is, the solenoid valve 15,
16 valve openings are equivalent to orifices, and solenoid valves 15, 1
It is also possible to control 6 by duty control. In this case, the orifice 17 is unnecessary.

Drain corresponding to the internal space volume reduced by the drainage from the oil / water separator 7 is supplied from the oil separator 3 through the drain pipe 8 into the oil / water separator 7 during the draining operation of the oil / water separator 7. It

Since the oil in the compressed air is separated and collected by the oil separator 3 and the oil / water separator 7 in this way, the amount of oil consumed is small. Further, since the water separated and discharged has a very small amount of oil content, it can be discharged by a simple post-treatment, for example, by passing it through a tank filled with an oil adsorbent.

The oil accumulated in the oil separation element 3d is always sent to the oil return pipe 5 through the return oil pipe 9 whose inlet is opened in the oil separation element 3d, so that the discharge pipe 4'is formed together with the compressed air.
The oil is prevented from being sent out to complement the oil separation ability of the oil separation element 3d.

In the figure, G indicates a power lamp indicating that the control device 21 is energized, and a push button switch PB.
Are provided to test the operation of the solenoid valves 15 and 16.

In this embodiment, since the electric motor 2 and the control device 21 are interlocked with each other, the compressed air pressure in the oil separator 3 is always maintained, so that the liquid in the oil / water separator 7 is pressurized. Therefore, a predetermined amount of water is always drained during the set time of the timer T1. If the electric motor 2 and the control device 2
If 1 is not linked, even if the compressed air pressure in the oil separator 7 is lost, the solenoid valves 15 and 16 are opened for the set time of the timer T1, but drainage cannot be sufficiently performed, and the oil-water separator 7 is sufficient. It doesn't work.

[Embodiment 2] In this embodiment, the upper and lower limit water level detecting members in the oil / water separator 7 are provided to control drainage.

As shown in FIG. 3, the oil / water separator 7 has a lower limit water level probe 26a for detecting that the water level has reached the lower limit water level L and an upper limit water level probe 26b for detecting that the water level has reached the upper limit water level H, respectively. The tips are provided at the lower limit water level L and the upper limit water level H. Further, a submersible electrode 26c submerged in water, an AC power source 26d having one end connected to the submersible electrode 26c, a lower end water level probe 26a, and an upper limit water level probe 26b inserted between the other end of the AC power source 26d The first current detectors 26e and 26f are provided.

The output terminal of the first current detector 26e is coupled to the set terminal S of the flip-flop 31b via the inverter 31a, and the output terminal of the second current detector 26f is coupled to the reset terminal R of the flip-flop 31b. Has been done.

Positive phase output terminal Q of the flip-flop 31b
The output terminal of the driver 31c, to which the input terminal is coupled, is coupled to the relay RL. The normally open contact RL-1 of the relay RL is interposed between the power source and the solenoid valves 15 and 16. .

The drain sent from the oil separator 3 is separated into oil and water by the oil / water separator 7, and the separated separated oil is returned to the oil return pipe 5 by the separated oil return pipe 12 as in the first embodiment.
On the other hand, the separated water accumulates at the bottom of the oil / water separator 7. As the oil-water separation progresses, the water level of the oil-water separator 7 rises, and the upper limit water level probe 26 whose tip has been in the separated oil until now.
Since b comes into contact with water, the underwater electrode 26c and the upper limit water level probe 26b are electrically connected by the water W in the oil / water separator 7, and the AC power supply 2
6d-Underwater electrode 26c-Water W-Upper limit water level probe 26b
The load circuit of the first current detector 26e is formed, the first
The current detector 26e detects the current and outputs (1). This signal is converted by the inverter 31a from (1) to (0) and is input to the set terminal S of the flip-flop 31b, so that the flip-flop 31b is set and the (1) is output from its positive phase output terminal Q. As a result, the driver 31c is brought into conduction and the relay RL is energized to make its normally open contact RL
Since -1 is closed, the coils SV of the solenoid valves 15 and 16 are
A and SVB are energized, the solenoid valves 15 and 16 are opened, the water W in the oil / water separator 7 is pushed out by the compressed air pressure,
The flow rate is regulated to flow out through the solenoid valves 15 and 16 and the orifice 17 which are opened in the discharge pipe 14.

When the water level in the oil / water separator 7 drops due to the outflow of water W and the lower limit water level probe 26a releases water,
The second current detector 26f, which has output (1), outputs (0). The positive phase output terminal Q of the flip-flop 31b to which the signal from (1) to (0) is input to the reset terminal R is
The signal changes from (1) to (0), the driver 31c is opened, the relay RL is deenergized, and the normally open contact RL-1 is opened, so that the solenoid valves 15 and 16 are closed. The water level rises again,
The lower limit water level probe 26a lands on the first current detector 26
f outputs (1) but simply (1) is applied to the reset terminal R as (1)
, The flip-flop 31b is not set.

[Third Embodiment] FIG. 4 is an alternative to the detection of the upper limit water level in the first embodiment. The oscillator 33a of the ultrasonic oscillator 33 is attached to the outer wall of the oil-water separator 7 at a position corresponding to the upper limit water level. When the water level of the water W rises, the water surface comes to the position of the vibrator 33a, so that the excitation power differs and the output of the ultrasonic oscillator 33 fluctuates. This fluctuation is input to the ON / OFF signal generator 34 to generate an ON / OFF signal, the ON / OFF signal is sent to the control device 21, and the solenoid valves 15 and 16 are opened. The opening time of the solenoid valves 15 and 16 is the same timer as in the first embodiment.

[0053]

According to the first aspect of the present invention, the drain is led from the oil separator of the oil supply type air compressor to the oil-water separator,
The separated oil separated by the oil / water separator is returned directly from the oil separator to the oil return pipe to the oil supply air compressor or to the oil supply air compressor, and the oil separated by the oil / water separator flows out through the flow control member. As a result, the amount of oil consumed can be reduced, and the amount of oil mixed with the discharged wastewater is small, so that the wastewater can be easily treated.

In the second aspect of the present invention, since the flow rate regulating member in the first aspect is the solenoid valve, it is possible to drain only the water separated by the oil-water separator by intermittently opening and closing the solenoid valve. it can.

In the third aspect of the present invention, the flow rate of waste water can be regulated by one solenoid valve in the second aspect.

In the fourth aspect of the present invention, since the plurality of solenoid valves are arranged in series in the second aspect of the present invention, even if the remaining one solenoid valve is not completely closed by foreign matter, the drain valve Will not be washed away.

According to the fifth aspect of the present invention, in the first aspect of the present invention, since the orifice and the electromagnetic valve are arranged in series as the flow rate controlling member, it is easy to provide a drainage flow path corresponding to the amount of drainage from the oil / water separator. is there.

According to the sixth aspect of the present invention, in any one of the second to fifth aspects, since the control device for intermittently opening the solenoid valve for the required time by the timer is provided, only the water separated by the oil / water separator is provided. Can be easily and automatically drained.

In a seventh aspect of the present invention, in the sixth aspect, the oil-water separator is a closed tank, and is provided with a detection member for detecting the rising limit position of the water surface of the separated water which has been separated. By providing the control device for performing the time-limited control of the valve opening by the signal, it is possible to prevent the water separated in the oil-water separator from returning to the separated oil flow of the oil separator and mixing again.

The eighth invention of the present invention comprises a member for detecting the upper and lower limit water levels of the separated water separated by the oil-water separator in any one of the second to fifth inventions, and the electromagnetic wave is detected by the signal of the detecting member. Since the control device for controlling the valve is provided, it is possible to reliably discharge only the separated water.

In a ninth aspect of the present invention, in the eighth aspect of the present invention, the detection water surface of the water level detecting member for detecting the descent limit position of the water surface is provided above the drain port of the oil-water separator. Also, drain can be prevented from flowing out.

The tenth invention of the present invention is the oil separation device according to any one of the first to ninth inventions, wherein a flow control member is interposed between the oil / water separator and the oil reflux circuit of the oil separator or the oil supply type compressor. Since the reflux circuit is provided, the separated oil separated by the oil / water separator does not have to be separately taken out and returned, and the separated oil can be automatically recovered and returned to the oil circulation circuit of the air compressor.

An eleventh invention of the present invention is the fuel cell system according to any one of the first to tenth inventions, wherein a solenoid valve control device provided in an outflow passage of the water separated by the oil-water separator is linked with an air compressor. Therefore, compressed air pressure is always applied to the oil-water separator, and the separated water is always drained.

The twelfth invention of the present invention is the oil-water separator according to the seventh invention, which comprises a float floated by the separated water and a water level detecting member operated by the rise of the float, and the float does not reach the bottom of the oil-water separator. As described above, the stopper is provided so that the water level of the separated water is higher than the drain port so that the separated water remains on the bottom of the tank. Therefore, it is possible to prevent the separated oil and the drain from flowing out during the drainage operation.

[Brief description of drawings]

FIG. 1 is a flow sheet of Example 1 of the present invention.

FIG. 2 is an operation explanatory diagram in FIG.

FIG. 3 is a flow sheet showing a main part of a second embodiment of the present invention.

FIG. 4 is a flow sheet showing a main part of a third embodiment of the present invention.

[Explanation of symbols]

 1 Refueling Air Compressor 2 Electric Motor 3 Oil Separator 4 Discharge Pipe 5 Oil Return Pipe 7 Oil Water Separator 8 Drain Pipe 12 Second Oil Separation Return Pipe 13 Orifice 14 Drain Pipe 15, 16 Solenoid Valve 17 Orifice 21 Control Device

Claims (12)

[Claims] Claim: What is claimed is: 1. An oil recovery device in an oil supply type air compressor having an oil recirculation circuit for returning the oil separated from the oil separator installed in the discharge pipe of the oil supply air compressor to the air compressor. The drain in the accumulated separated oil is guided to the oil / water separator, and the oil separated into oil and water by the oil / water separator is returned directly from the oil / water separator to the oil reflux circuit or the oil supply air compressor, and at the same time, the oil / water separator. An oil recovery device in a refueling type air compressor, characterized in that the separated water separated in step 1 is allowed to flow out through a flow rate regulating member. 2. The oil recovery device in a refueling type air compressor according to claim 1, wherein the flow rate regulating member is a solenoid valve. 3. The oil recovery device in a refueling type air compressor according to claim 2, wherein the number of the solenoid valves is one. 4. The oil recovery device for a refueling type air compressor according to claim 2, wherein a plurality of the solenoid valves are provided in series. 5. The oil recovery apparatus for a refueling type air compressor according to claim 1, wherein the flow rate regulating member is an orifice and a solenoid valve, and the solenoid valve is provided in series with the orifice. 6. The refueling type air compressor according to any one of claims 2 to 5, wherein the solenoid valve has a control device which is normally closed and is intermittently opened by a timer for a required time. Oil recovery device. 7. The oil-water separator is a closed tank, and is provided with a water level detection member for detecting the rising limit position of the water surface of the separated water, and the time limit control for opening the valve is started by a signal detected by the water level detection member. The oil recovery device in the refueling type air compressor according to claim 6, further comprising a control device for controlling the oil recovery device. 8. The oil-water separator comprises a detection member for detecting the upper and lower limit positions of the water surface of the separated water separated in the closed tank, and the detection member opens a solenoid valve in response to a signal detecting the upper limit water level, The oil recovery device for a refueling type air compressor according to any one of claims 2 to 5, further comprising a control circuit that closes an electromagnetic valve according to a signal that detects a lower limit water level. 9. The oil recovery device in an air compressor according to claim 8, wherein the water level detection member for detecting the descent limit position of the water surface is provided above the drain port of the oil-water separator. 10. A separated oil recirculation in which one end communicates with the space occupied by the separated oil in the upper part of the oil-water separator, and the other end communicates with an oil recirculation circuit or a refueling type air compressor, with a flow regulating member interposed. A circuit is provided, The oil recovery device in the oil supply type air compressor according to any one of claims 1 to 9 characterized by things. 11. The air according to any one of claims 1 to 10, characterized in that a control device of a solenoid valve provided in an outflow passage of the water separated by the oil-water separator is linked with an air compressor. Oil recovery device in compressor. 12. The oil-water separator is provided with a float that floats up by the separated water and a water level detection member that operates when the float rises, and the float has a stopper that limits the descent of the float so that it does not reach the bottom of the oil-water separation tank. The oil recovery device for an air compressor according to claim 7, wherein the oil recovery device has a space provided between the float and the bottom of the tank so that the water level of the separated water is higher than the drain port.