JPH11257227A - Drainage discharge method and system for post-stage cooler of compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drainage discharge method and system for a post-stage cooler in a compressor, which both offer an efficient operation of the compressor. SOLUTION: A drain pipe 22 provided with a drain valve 40 is equipped to discharge the drainage that is collected in a drain tank 20 while a post-stage cooler 18 cools down the compressed air expelled from a receiver tank 16. The drain valve 40 is operationally opened or closed in dependence on the internal pressure of the receiver tank 16 or in association with the opening/ closing action of a volume controller 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for discharging a drain of a rear cooler of a compressor, and more particularly to a drain tank which is generated when compressed air is cooled by a rear cooler and communicates with the rear cooler. The present invention relates to a method and an apparatus for discharging a drain of a rear cooler, which automatically opens and closes a drain valve for discharging water (drain) collected therein to discharge the drain.

[0002]

2. Description of the Related Art Compressed air discharged from a compressor body 12 is hot and humid due to a compression action.

[0003] When high-temperature and high-humidity compressed air is directly supplied to an air working machine (not shown) or the like, the compressed air is cooled in a compressed air supply pipe, and water vapor contained in the compressed air condenses to generate drain. However, since the drain is supplied into the pneumatic working machine, the working machine may be damaged.

Therefore, in order to solve various problems caused by drainage, compressed air discharged from the compressor body 12 is once introduced into the rear cooler 18 and cooled, and the compressed air is previously cooled by this cooling. There is a compressor 10 configured to condense water vapor contained therein to generate a drain and supply compressed air from which the drain has been removed to an air working machine or the like (FIG. 7).

[0005] The rear cooler 18 of the compressor 10 is shown in FIG.
Is connected to the drain tank 20 so that the drain generated in the rear cooler 18 can be separated and collected in the drain tank 20 from the compressed air.

[0006] The compressed air from which the drain has been removed is supplied to the consumer side, and the drain collected in the drain tank 20 is discharged through a drain outlet 21 formed in the drain tank 20 to the outside of the machine. It is constituted so that it can be discharged to.

340 is a drain discharge pipe 22 (22a, 22
b) is a drain valve provided therein. If the drain valve 340 is slightly opened during the operation of the compressor 10, the drain collected in the drain tank 20 is discharged to the outside together with the compressed air. Is discharged.

[0008] When the compressor 10 is stopped,
With the drain valve 340 fully opened, the drain tank 20
The drain valve is manually opened and closed so that the drain collected inside is completely discharged outside the machine.

[0009]

As described above, the conventional compressor 10 having a structure in which the drain valve 340 is manually opened / closed.
In this case, since it is complicated to open and close the drain valve 340 or adjust the degree of opening in accordance with the operating state of the compressor 10, once the compressor 10 is started, the drain valve 340 is appropriately opened. After being adjusted and opened each time, the compressor 10 is not opened or closed even when the compressor 10 is switched from the load operation to the no-load operation, for example.

However, when the compressor 10 is operating at no load, no compressed air is consumed, and therefore no compressed air is introduced into the rear cooler 18. Therefore, the drain is not collected in the drain tank 20, and it is not necessary to open the drain valve 340. When the drain valve 340 is opened, the compressed air in the receiver tank 16 is discharged through the drain valve 340. When the pressure in the receiver tank 16 is reduced and the pressure is reduced to the load operation start pressure of the compressor main body 12, even if the compressed air is not consumed on the consuming side, the compressor is discharged. The main body 12 starts the load operation. Therefore, the load operation consumes extra power or fuel.

Further, while the compressor 10 is operating, the drain valve 340 is half-opened to discharge the drain together with the compressed air. However, since the drain valve 340 is manually opened and closed, the drain valve is opened. It is difficult to adjust 340 to open drain valve 340 at an optimal opening.

Therefore, if the opening of the drain valve 340 is small, the drain is not sufficiently discharged and moisture is mixed in the compressed air supplied to the consuming side. On the other hand, if the drain valve 340 is opened excessively, the drain and the outside The amount of compressed air discharged to the receiver tank 16 increases, and the pressure in the receiver tank 16 is excessively reduced, thereby causing a problem such as a decrease in the pressure of the compressed air supplied to the consuming side of an air working machine or the like (not shown). .

Further, when the drain valve 340 is manually opened and closed as described above, the same problem as described above occurs such that a large amount of water is mixed in the supplied compressed air due to forgetting to open the drain valve 340.

In addition, when the drain valve 340 is manually opened and closed as described above, if the drain valve 340 is not opened when the compressor 10 is stopped, the drain valve 340 may be rusted or the drain may be frozen. Opening and closing may be difficult, which may cause drain discharge failure.

The present invention has been made in order to solve the above-mentioned drawbacks in the prior art.
A mechanism capable of automatically opening and closing the drain valve 40 is provided, so that there is no need to open and close the drain valve, and malfunctions due to human error such as forgetting to open and close the drain valve can be prevented. A compressor 1 that preferably discharges collected drain and minimizes the discharge of compressed air that has been discharged together with the discharge of the drain, thereby causing no power loss.
It is an object of the present invention to provide a method and an apparatus for draining a rear cooler.

[0016]

In order to achieve the above object, the method and apparatus for discharging the rear cooler drain of the compressor 10 of the present invention compress the air sucked through the intake ports 62, 162, 262. The compressor body 12 discharges and discharges, and operates according to the set pressure of the compressed air discharged from the compressor body 12 to operate the intake ports 62, 162, 162 of the compressor body 12.
A rear cooler 18 for cooling the compressed air discharged from the compressor body 12 and a compressor for cooling the compressed air; and a capacity control device 60, 160, 260 for opening and closing the 262 with the unloader valves 64, 164, 264. The drain tank 20 includes a drain tank 20 for collecting the drain generated by the drain tank 20 and a means for discharging the drain collected in the drain tank 20 to the outside of the machine.
Valves 40, 14 for opening and closing the drain outlet 21 of the
0, 240, and the capacity control devices 60, 1
60,260 unloader valves 64,164,264
In conjunction with the opening and closing of the intake ports 62, 162, 262 by
The drain outlet 21 is opened and closed (claims 1 and 3).

In the method and apparatus for discharging the drain of the rear cooler, preferably, the drain valves 40, 140, and 2 are provided.
Reference numeral 40 designates the unloader valves 64, 164, 264 of the capacity control devices 60, 160, 260
The drain outlet 21 is closed when the second and second cylinders 262 are closed (claims 2 and 4).

The interlocking between the capacity control device 60 and the drain valve is performed by, for example, the drain outlet 2 of the drain tank 20.
1 is provided with an electromagnetic valve 40 to form a drain valve, and the electromagnetic valve 40 is powered by a pressure switch 50 for detecting the pressure in the receiver tank 16 to which the compressed air discharged from the compressor body 12 is supplied. And the operating pressure of the pressure switch 50 is set to substantially the same pressure as the pressure in the receiver tank 16 when the unloader valve 64 closes the intake port 62, and the intake port 62 is opened and closed by the unloader valve 64. The solenoid valve 40 which is a drain valve may be opened / closed in conjunction with (Claim 5, FIG. 1).
Further, instead of the pressure switch 50 for detecting the pressure in the receiver tank 16, the pressure in the suction chamber 26 of the compressor body 12 on the downstream side of the displacement control device and on the upstream side of the intake port 62, for example, Pressure switch 5 for detecting pressure
The solenoid valve 40 is connected to a power source via 0 ',
The operating pressure of the pressure switch 50 'is set to substantially the same pressure as the pressure in the suction chamber when the unloader valve 64 closes the intake port 62, and the drain is interlocked with the opening and closing of the intake port 62 by the unloader valve 64. The electromagnetic valve 40 as a valve may be configured to open and close (claim 6, FIG. 2).

When the displacement control device 160 is of a "valve lift type" in which an unloader valve 164 connected to the shaft 166 opens and closes an intake port 162 by moving the shaft 166 forward and backward, the drain valve The valve 140 may be provided with a valve body 144 that opens and closes the drain valve 140 in conjunction with the movement of the shaft 166. For example, the valve body of the drain valve 140 is formed as a spool-type valve body 144, and the capacity control is performed. Device 16
The spool valve element 144 is formed or arranged in the axial direction of the shaft
0 can be configured to open and close in conjunction with the movement of the shaft 166 (claim 7, FIG. 3).

Further, the displacement control device 260 is a butterfly type in which an unloader valve 264 fixed to the shaft 266 swings in the intake port 262 to open and close the intake port 262 by the rotation of the shaft 266. In this case, the drain valve 240 is provided with a valve body that opens and closes the drain valve 260 in conjunction with the rotation of the shaft 266. For example, the drain valve 240 is formed in the drain valve 240 and includes the drain outlet 21. A valve body is provided in a drain passage 248 (248a, 248b) communicating with the valve, and the valve body opens and closes the passage 248 (248a, 248b) in conjunction with the rotation of the shaft 266 of the capacity control device 260, that is, The drain valve 240 may be configured to open and close (claim 8, FIGS. 4 to 6). In this case, the valve body may be formed by, for example, the shaft of the capacity control device 260, or may be attached to the shaft 266 of the capacity control device 260.

[0021]

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Embodiment 1] In FIG. 1, reference numeral 10 denotes a compressor. The compressor 10 is, for example, a screw-type compressor body 12 (see FIG. 3) for sucking air and compressing it.
A motor 14 for driving the compressor main body 12, such as a motor and an engine; a receiver tank 16 to which compressed air discharged from the compressor main body 12 is supplied; and a pressure in the receiver tank 16. If the value is equal to or greater than the value, the intake port 62 of the compressor body 12 is closed, and the compressor body 1
2 is in a so-called "no-load operation" state, and when the pressure in the receiver tank 16 falls below a set value, the intake port of the compressor body 12 is opened to cause the compressor body 12 to perform a so-called "load operation". A capacity control device 60 is provided. The discharge from the receiver tank 16 is provided between pipes 32 and 34 that communicate the receiver tank 16 with a compressed air consuming side such as an air working machine (not shown). Rear cooler 18 for cooling the compressed air, and a drain tank 20 for collecting drain generated by cooling by the rear cooler 18.
Is provided.

The rear cooler 18 is connected to the compressor main body 1.
Any of an air-cooled aftercooler, a water-cooled aftercooler, and a refrigeration dryer may be used as long as it cools the compressed air discharged from 2.

At the lower end of the drain tank 20, there is provided a drain outlet 21 for discharging the water in the compressed air collected in the drain tank 20 to the outside of the machine.
A drain discharge pipe 22 is connected to the drain discharge port 21. The drain discharge pipe 22 is provided with a drain valve 40 for opening and closing the drain discharge pipe 22, and has the same configuration as the conventional compressor 10 in the above points.

In the compressor 10 of the present embodiment, an electromagnetic valve 40 is connected to a drain outlet 21 of the drain tank 20 via a drain discharge pipe 22 (22a).
The solenoid valve 40 is a drain valve.

A pressure switch 50 for detecting the pressure in the receiver tank 16 is provided, and a power supply (not shown) for operating the solenoid valve 40 is connected to the solenoid valve 40 via the pressure switch 50. I have.

As an example, a solenoid valve 40 that is closed when energized is used as the solenoid valve 40. When the pressure in the receiver tank 16 is equal to or less than a preset value, the solenoid valve 40 is closed. If the pressure in the receiver tank 16 drops below the set value, the pressure switch 50 detects this. OFF
While switching the solenoid valve 40 to the open position,
When the pressure in the receiver tank 16 rises above a set value, the pressure switch 50 detects this pressure rise and
N, the solenoid valve 40 is closed and the solenoid valve 40
The discharge of compressed air, which is performed via

Further, when the compressor 10 itself is stopped and the energization to the solenoid valve 40 is stopped, the solenoid valve 40 is opened and all the drain in the drain tank 20 is discharged. Therefore, the solenoid valve 40 may be rusted or frozen due to accumulation of the drain in the drain tank 20 for a long time.
Malfunction, drain discharge failure, etc. can be prevented.

In the compressor 10 provided with the discharge device of the rear cooler drain constructed as described above,
The passage of the solenoid valve 40 is opened until the pressure in the receiver tank 16 reaches the operating pressure of the pressure switch 50. Therefore, the operating pressure of the pressure switch 50 is reduced by the unloader valve 64 of the displacement control device 60. 62
The compressor 10 operates as follows by setting the same pressure as the pressure in the receiver tank 16 when opening and closing the compressor.

If the amount of compressed air supplied from the compressor body 12 into the receiver tank 16 becomes larger than the amount of compressed air consumed on the consuming side due to a stop of an air working machine not shown, etc., the receiver tank 16 The pressure inside gradually rises,
When the pressure in the receiver tank 16 reaches a predetermined pressure, the unloader valve 64 of the capacity control device 60 closes the intake port 62 of the compressor body 12 and the pressure switch 50 switches the solenoid valve 40
Switches to the close position. Therefore, the drain tank 20
Drain discharge in the chamber stops.

Thereafter, when the pressure in the receiver tank 16 is reduced by, for example, restarting an air working machine (not shown), the unloader valve 64 of the capacity control device 60 opens the intake port of the compressor body 12 to load the load. With the start of operation, the pressure switch 50 is switched to the position where the solenoid valve 40 is opened, the drain in the drain tank 20 is discharged outside the machine, and with the pressure change in the receiver tank 16,
The above operation is repeated.

When the compressor 10 itself is stopped, the energization of the solenoid valve 40 is also stopped, and the solenoid valve 40 is opened to completely drain the compressed air in the receiver tank 16 and the drain in the drain tank 20. It is possible to suitably prevent poor opening and closing of the solenoid valve 40 which is released outside the machine and is caused by rusting, freezing of drain, and the like.

With the above configuration, the compressor 1 of the present embodiment
At 0, unlike a conventional compressor in which the solenoid valve 40 is always open, the solenoid valve 40 is closed during a no-load operation in which drain does not accumulate in the drain tank 20, so that compressed air is wasted outside the machine. Without discharging, the compressor 10 can be operated efficiently. Therefore, power consumption or fuel consumption can be reduced.

The capacity control device 60 and the drain valve of the present embodiment operate in accordance with the pressure in the receiver tank 16, but the pressure of the compressed air discharged from the compressor body 12, for example, a pipe communicating with the consumer side. The pressure control device 60 and the drain valve may be actuated by the pressure in 34.

[Second Embodiment] Next, another embodiment of the drain discharge device for the rear cooler of the compressor according to the present invention will be described.

In the embodiment shown in FIG.
Are the compressor body 12, the capacity control device 60, the prime mover 14, the receiver tank 16, the rear cooler 18, and the drain tank 2.
0 and a point that an electromagnetic valve 40 which is a drain valve for opening and closing the drain outlet 21 of the drain tank 20 is provided is the same as the embodiment shown in FIG.

In the compressor 10 of the embodiment shown in FIG. 1, the solenoid valve 40 is connected to a power supply via a pressure switch 50 for detecting the pressure in the receiver tank 16, whereas the present embodiment is different from the embodiment shown in FIG. In the compressor 10 of the embodiment, FIG.
A pressure switch 50 ′ for detecting the pressure in the suction chamber 26 of the compressor body 12 on the downstream side of the capacity control device 60 and on the upstream side of the suction port 62, instead of the pressure switch 50, The solenoid valve 40 is connected to a power source through the unloader valve 6 of the capacity adjusting device 60.
4, the electromagnetic valve 40 can be opened and closed in conjunction with the opening and closing of the intake port 62 of the compressor body 12.

As an example, a solenoid valve that is closed when energized is used as the solenoid valve 40, and the solenoid valve 40 is provided downstream of the atmospheric flow path of the displacement control device 60 and upstream of the intake port 62. When the pressure in the suction chamber 26 falls below a preset value (negative pressure), this is detected and turned on.
, And is connected to a power supply via a pressure switch 50 ′ which is turned off when it rises above the set value.

Then, when the unloader valve 64 of the displacement control device 60 closes the intake port 62 of the compressor body 12 and the pressure in the suction chamber 26 falls below the set value (negative pressure), the pressure switch 50 'is turned on. Is detected and turned ON to switch the electromagnetic valve 40 to the closed position.

On the other hand, when the unloader valve 64 of the displacement control device 60 opens the intake port 62 of the compressor body 12 and the pressure in the suction chamber rises above the set pressure value, the pressure switch 50 'detects this pressure value. Then, the solenoid valve 40 is opened, and the drain is discharged together with the compressed air through the solenoid valve 40.

Therefore, when the unloader valve 64 of the displacement control device 60 opens the intake port 62 of the compressor body 12, that is, during the load operation, the pressure in the suction chamber is substantially equal to the operating pressure of the pressure switch 50 '. , The compressor 10 operates as follows.

If the amount of compressed air supplied from the compressor body 12 into the receiver tank 16 becomes larger than the amount of compressed air consumed on the consuming side due to a stop of an air working machine not shown, etc., the receiver tank 16 The pressure inside gradually rises,
When the pressure in the receiver tank 16 reaches a predetermined pressure, the unloader valve 64 of the capacity control device 60 closes the intake port 62 of the compressor body 12.

When the intake port 62 of the compressor body 12 is closed by the unloader valve 64 of the displacement control device 60, the intake of air into the intake chamber 26 communicating with the intake port 62 is stopped. Then, in this state, the compressor body 1
2, for example, screw rotors 24a, 24b (see FIG. 3)
When the rotation of the suction chamber 26 continues and the pressure in the suction chamber 26 decreases to a negative pressure, the pressure switch 50 'switches to a position at which the pressure switch 50' closes the solenoid valve 40 by detecting a decrease in the pressure (negative pressure). Therefore, the discharge of the drain from the drain tank 20 is stopped.

Thereafter, when compressed air is consumed by restarting an air working machine (not shown) and the pressure in the receiver tank 16 is reduced, the capacity control device 60 opens the intake port 62 of the compressor body 12. .

Then, when the load operation is started by the opening of the intake port 62 and the compressor body 12 starts intake,
Air is sucked into the suction chamber 26 to increase the pressure in the suction chamber 26, the pressure switch 50 'switches to a position to open the solenoid valve 40, the drain in the drain tank 20 is discharged outside the machine, and the receiver The above operation is repeated with a change in the pressure in the tank 16.

Therefore, even in the compressor 10 of the present embodiment, the unloader valve 64 is connected to the intake port 6 of the compressor body.
The solenoid valve 40, which is a drain valve, can be opened and closed in conjunction with the opening and closing operation of the solenoid valve 2, and the solenoid valve 40 is closed during a no-load operation in which drain does not accumulate in the drain tank 20. The compressor 10 can be operated efficiently without discharging to the outside. Therefore, power consumption or fuel consumption can be reduced.

[Third Embodiment] Next, another embodiment of the drain discharge device for the rear cooler of the compressor according to the present invention will be described.

In the embodiment shown in FIG. 3, the compressor body 12, the capacity control device 160 for opening and closing the intake port of the compressor body, and the capacity control device among the equipment constituting the compressor 10 of the present invention. 160 shows only the drain valve 140 integrally formed with the motor 160, the motor 14, the receiver tank 1
6, the rear cooler 18 and the drain tank 20 are omitted.

The motor 14, the receiver tank 16,
The arrangement of the rear cooler 18, the drain tank 20, and the like are the same as in the embodiment in FIG.

In FIG. 3, reference numerals 24a and 24b denote known screw rotors.
When the rotors a and 24b mesh with each other and rotate, the air in the suction chamber 26 in which the screw rotors 24a and 24b are housed is sucked between the two rotors 24a and 24b, compressed and discharged. .

The compressed air is sucked into the suction chamber 26 containing the screw rotors 24a and 24b.
Control device 160 for opening and closing intake port 162 communicating with
Is controlled by

This displacement control device 160
The shaft 1 that moves forward and backward through the intake port 162 communicating with
A known volume control device which is closed from the suction chamber 26 side by an unloader valve 164 attached to the valve 66, that is, a “valve lift type” volume control device. In the present embodiment, an unloader having an opening 165 in the center is formed. A valve 164 and a shaft 166 passing through the central opening 165 of the unloader valve 164, and a flange 166a formed at one end of the shaft 166 protruding through the central opening 165 of the unloader valve 164
Between the unloader valve 164 and the shaft 1
66, a coil spring 168 is fitted, and the unloader valve 164 is urged by the coil spring 168 so that the intake port 162 is connected to the unloader valve 164.
It is constituted so that it may be closed by.

The other end of the shaft 166 is fixed to a diaphragm 170 which normally swells toward the unloader valve 164 (downward in FIG. 2), and a pressure receiving chamber 172 partitioned by the diaphragm 170 is provided. When compressed air is introduced into the diaphragm 170, the diaphragm 170 expands and deforms in the opposite direction (upward in FIG. 2) against the urging force of the coil spring 169, and moves forward and backward through the shaft 166 fixed to the diaphragm 170. It is configured to obtain.

Accordingly, the capacity control device 160 having the above-described configuration is used.
When the diaphragm 170 is bulging downward in FIG. 2 and the rotation of the rotors 24a and 24b produces a negative pressure in the suction chamber 26, the negative pressure causes the unloader valve 164 to bias the coil spring 168. 2 is drawn toward the suction chamber 26 as indicated by the two-dot chain line in FIG.
62 is opened, the outside air is sucked into the suction chamber 26, and the compressor body 12 is in a load operation state.

On the other hand, when the pressure in the receiver tank 16 rises above a preset value due to the compressed air discharged from the compressor body 12, the compressed air in the receiver tank 16 is partitioned by the diaphragm 170. The pressure is introduced into the pressure receiving chamber 172 to expand and deform the diaphragm 170 upward in FIG. 2, and the unloader valve 164 closes the intake port 162.

Therefore, no air is sucked into the suction chamber 26 from the suction port 162, and the compressor main body is operated under no load.

In the present embodiment, a drain valve 140 is provided which opens and closes in conjunction with the movement of the shaft 166 of the displacement control device 160, and the drain valve 140 interlocks with the opening and closing of the intake port 62 by the displacement control device 160. 2, the drain valve 140 is attached to the displacement control device 160, and the drain valve 140 is opened and closed.

The drain valve 140 may be formed separately from the displacement control device 160, and may be fixed to the displacement control device 160 or disposed near the displacement control device 160. As an example, in the present embodiment, the diaphragm 1 of the capacity control device 160 is used.
70 is formed integrally with a cover 174 that covers the upper surface 70, and the inside of an opening 142 formed at the center of the top of the cover 174 is a spool type that moves forward and backward on the axial extension of the shaft 166 of the capacity control device 160. The valve body 144 includes a return spring 146 that presses the upper end of the spool-type valve body 144 downward in FIG.

The cover 174 into which the spool-type valve element 144 is inserted is orthogonal to the axial direction of the spool-type valve element 144 inserted into an opening 142 formed at the center of the top of the cover 174. A passage 148 through which a drain passes is formed in the direction, and the drain passage 148 is divided into two (148 a, 148 b) by a spool type valve body 144 inserted into the opening 142.

The drain outlet 21 of the drain tank 20 is connected to one end 148a of the passage 148 through a pipe 22a forming a part of the drain outlet pipe 22, and a part of the drain outlet pipe 22 is connected to the other end 148b. Are connected, and a drain discharge pipe 22 is formed by the pipes 22a and 22b.

The spool-type valve element 144 urged downward by the return spring 146 is located at a position where it intersects with the passage 148 in the circumferential direction of the groove 1.
49 is formed, so that the drain introduced into the passage 148a can pass through the passage 148b through a groove 149 formed in the spool-type valve body 144.

Further, the lower end of the spool type valve body 144 is disposed so as to face the upper end of the shaft 166 of the displacement control device 160, and the spool 166 of the drain valve 140 is moved by the movement of the shaft 166 of the displacement control device 160. The lower end of the mold valve body 144 is configured to be pushed upward. The spool-type valve body 144 may be formed separately from the capacity control device 160 as shown in FIG.
The shaft type valve body 144 formed separately from the shaft 166 of the shaft
6 or the shaft 166 of the capacity control device 160
The groove 149 is formed in the
For example, the spool-type valve body 144 and the shaft 166 of the capacity control device 160 may be integrally formed.

The compressor body 12 configured as described above,
In the compressor 10 having the capacity control device 160 and the drain valve 140, when the compressor 10 is started, when the pressure in the receiver tank 16 is low, compressed air flows into the pressure receiving chamber 172 partitioned by the diaphragm 170. The diaphragm 170 is not introduced, and therefore, the diaphragm 170 is swelled downward as shown in FIG. 2, and the unloader valve 164 can be moved downward in FIG. 2 by the negative pressure in the suction chamber 26. That is, the intake port 162 is in an open state, and the compressor body 12 is in a load operation state.

Then, when the compressor body 12 continues the load operation and the pressure in the receiver tank 16 rises above a set value, a pressure regulator (not shown) which operates by the set pressure is opened, and the receiver is opened. Tank 16
A part of the compressed air inside is introduced into the pressure receiving chamber 172 of the capacity control device 160.

By introducing compressed air into the pressure receiving chamber 172, the diaphragm 170 of the capacity control device 160
The diaphragm 1 swells and deforms upward in FIG.
Due to the deformation of the shaft 70, the shaft 166 fixed to the diaphragm 170 moves upward, the unloader valve 164 is closed, and the compressor body 12 is in a no-load operation state.

As described above, when the shaft 166 of the displacement control device 160 moves upward due to the deformation of the diaphragm 170, the spool-type valve of the drain valve 140 disposed on the axial extension of the shaft 166. The body 144 is moved upward in FIG. 2 against the urging force of the return spring 146.

Then, the groove 149 of the spool type valve element 144 arranged at a position intersecting the passage in the state of being urged downward moves upward, and this groove 149 is formed at the center of the top of the cover 174. The spool type valve element 144 is inserted into the opened hole 142 so that the
And the drain valve 140 is closed.

Therefore, the compressor 10 having the compressor body 12, the capacity control device 160, and the drain valve 140 having the above-described structure automatically closes when the compressor body 12 is operated under no load by starting the compressor. It is possible to provide a drain valve 140 that is open in a state, a load operation, and a stop state, so that it is not necessary to open and close the drain valve 140 and the compressor does not generate a pressure loss or the like due to the opening and closing. An exhaust system for the ten rear cooler drains can be provided.

In this embodiment, the valve lift type capacity control device provided with the unloader valve 164 which moves up and down by the deformation of the diaphragm is described as an example. 164 may move left and right.

[Embodiment 4] Further, another embodiment of the present invention is shown in FIGS. 4, 5, 6 (a) and 6 (b).

In the embodiment shown in FIG. 4, among the equipment constituting the compressor 10 of the present invention, a capacity control device 260 for opening and closing the intake port 162 of the compressor body 12, and an integral part of the capacity control device 260. Drain valve 240 formed in
Only the prime mover 14, the compressor main body 12, the receiver tank 16, the rear cooler 18, and the drain tank 20 are omitted.

The arrangement of the prime mover 14, the compressor body 12, the receiver tank 16, the rear cooler 18, and the drain tank 20 is the same as that of the embodiment shown in FIG. For example, the same one as shown in the embodiment of FIG. 2 can be used.

The capacity control device 260 in the present embodiment
Is a known so-called "butterfly-type" capacity control device, which is attached to the compressor body 12 as shown in FIG. 3 and communicates with the suction chamber 26 of the compressor body.
A body 263 that opens and closes 62 and is formed in a substantially endless annular shape, and forms an intake port 262 at a central opening thereof.
And a substantially disk-shaped unloader valve 26 formed to have the same diameter as the inside diameter of the intake port 262 for opening and closing the intake port 262.
4 and a shaft 266 protruding from the outer periphery of the unloader valve 264 on a diametrically extended line. The shaft 266 is inserted into a bearing 268 formed on the body 263 so that the unloader valve 264 is
It is configured to be swingable inside.

A shaft 266 oscillating the unloader valve 264 penetrates a bearing 268 formed on the body 263 and protrudes from the outer periphery of the body. The shaft 266 protrudes from the bearings 268, 268.
A lever 230 for swinging the unloader valve 264 is fixed to one end of the cylinder 6, and the pressure in the receiver tank 16 is set to a preset value by an air cylinder (not shown) connected to the lever 230, for example. In the case described above, the unloader valve 264 is swung to close the intake port 262 and switch to the no-load operation,
When the pressure in the receiver tank 16 becomes equal to or less than a preset value, the unloader valve 26
4 is opened to open the intake port 262, and the compressor body is configured to be in a load operation state.
This is similar to a butterfly-type displacement control device in a known compressor.

In the capacity control device 260 of the present invention,
In addition to the functions of the conventional butterfly type displacement control device described above, the intake port 262 of the displacement control device 260
A function of opening and closing the drain valve 240 in conjunction with opening and closing of the drain valve 240 is provided.

Although the drain valve 240 can be formed separately from the displacement control device 260, in this embodiment, the body 263 forming the intake port 262 is used.
The drain valve 240 is formed integrally with the insertion hole 242 of the valve body into which the shaft 266 serving as the valve of the drain valve 240 is inserted, and the shaft 266 inserted into the insertion hole 242 of the valve body. A passage 248 through which a drain formed in a direction perpendicular to the axial direction passes is formed, and the capacity control device 26 inserted into the drain valve 240 is formed.
The opening 249 penetrating in the diameter direction is formed in the 0 shaft 266.

In this embodiment, the valve body of the drain valve 240 is connected to the shaft 266 of the displacement control device 260.
In the following, an example in which the valve element is linked to the rotation of the shaft 266 of the capacity control device 260 will be described.
May be fixed to the shaft 266, or may be configured to interlock via a known interlocking mechanism.

The opening 24 formed in the shaft 266
9 is located on the same straight line as the passage 248 formed in the drain valve 240 when the unloader valve 264 opens the intake port 262, that is, when the compressor body 12 is in a load operation, and Is opened, and the unloader valve 264 is
When the compressor 2 is closed, that is, when the compressor body 12 is in a no-load operation, the opening 24 formed in the shaft 266 is formed.
9 is deviated from a passage 248 formed in the drain valve 240, and the passage 248 is configured to be divided by a shaft 266.

Therefore, by connecting the drain tank 20 to one end 248a of the passage 248 formed in the drain valve 240 via the pipe 22a, and connecting the pipe 22b extending outside the machine to the other end 248b. When the compressor body 12 is in the load operation, the drain in the drain tank 20 can be discharged outside the machine, and when the compressor body 12 is in the no-load operation, the drain valve 240 is closed to discharge the drain. It is configured to stop the operation and stop the discharge of the compressed air discharged outside the machine together with the drain.

Therefore, the butterfly type unloader valve 260 shown in this embodiment and the unloader valve 2
The compressor 10 provided with the drain valve 240 attached to the compressor 60 is automatically turned on by starting the compressor 10 to be in the closed state during the no-load operation of the compressor main body 12 and the open state during the load operation and the stop. A drain valve 240 that does not require the trouble of opening and closing the drain valve 240, and provides a discharge device for the rear cooler drain of the compressor 10 in which the opening and closing does not cause a pressure loss or the like. Can be.

[0081]

According to the structure of the present invention described above, the method and apparatus for discharging the rear cooler drain of the present invention have the following remarkable effects.

Since the drain valve is automatically opened and closed, not only the work complexity is reduced, but also the pressure in the receiver tank is reduced due to forgetting to close the drain valve, and the air working machine is compressed due to forgetting to open the drain valve. It is possible to prevent human error such as drain being supplied together with the compressed air to the air supply side, and by setting the opening of the drain valve appropriately, it is possible to obtain a sufficient drain which is difficult by manual adjustment. The release and the minimum required release of compressed air can be achieved.

When the compressor is in the load operation state,
Or, by opening the drain valve when the compressor is stopped and closing the drain valve when the compressor is operating under no load, the conventional drain discharge that remains open even during no load operation The loss of compressed air is smaller than that of a compressor provided with the device, and therefore, the consumption of electric power, fuel, and the like used when the compressor is operated can be reduced.

Further, when the compressor is stopped, the drain valve is opened due to the stop of energization or the pressure drop in the receiver tank, and the drain in the drain tank is discharged. Rust and freezing of the drain can be prevented, and malfunction of the drain valve due to the rust and freezing can be eliminated.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a compressor main body, a displacement control device, and a drain valve.

FIG. 4 is a plan view of a capacity control device formed integrally with the drain valve.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

6 is a sectional view taken along line VI-VI of FIG. 4, wherein (a) shows a state where an unloader valve is opened, and (b) shows a state where the unloader valve is closed.

FIG. 7 is a circuit diagram showing a conventional compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Compressor 12 Compressor main body 14 Motor 16 Receiver tank 18 Rear cooler 20 Drain tank 22 (22a, 22b) Drain discharge pipe 24a, 24b Screw rotor 26 Suction chamber 32, 34 Piping 40 Solenoid valve (Drain valve) 50 Pressure switch Reference Signs List 60 Capacity control device 62 Intake port 64 Unloader valve 140, 240 Drain valve 142 Opening 144 Spool type valve element 146 Return spring 148 (148a, 148b) Passage 149 Groove 160 Capacity control device (valve lift type) 162 Intake port 164 Unloader Valve 165 Opening 166 Shaft 168, 169 Coil spring 170 Diaphragm 172 Pressure receiving chamber 174 Cover 230 Lever 242 Valve element insertion hole 248 Passage 249 Opening 260 Capacity control device (Butterf B type) 262 inlet 263 Body 264 unloader valve 266 shaft 268 bearing

Claims (8)

[Claims] 1. A compressor main body for compressing and discharging air sucked through an air inlet, and an air intake of the compressor main body operated in accordance with a set pressure of the compressed air discharged from the compressor main body. With a capacity control device that opens and closes the opening with an unloader valve, a rear cooler that cools the compressed air discharged from the compressor main body, and a drain tank that collects drain generated by cooling the compressed air, Means for discharging the drain collected in the drain tank to the outside of the machine, a drain valve for opening and closing a drain outlet of the drain tank is provided, and an intake port by an unloader valve of the capacity control device. A drain outlet for the compressor, wherein the drain outlet is opened and closed in conjunction with opening and closing of the compressor. 2. The method according to claim 1, wherein the drain valve closes a drain discharge port when an unloader valve of the capacity control device closes an intake port. 3. A compressor main body for compressing and discharging air sucked through an air inlet, and an air intake of the compressor main body operating in accordance with a set pressure of the compressed air discharged from the compressor main body. With a capacity control device that opens and closes the opening with an unloader valve, a rear cooler that cools the compressed air discharged from the compressor main body, and a drain tank that collects drain generated by cooling the compressed air, Means for discharging the drain collected in the drain tank to the outside of the machine, a drain valve for opening and closing a drain outlet of the drain tank is provided, and an intake port by an unloader valve of the capacity control device. A drain outlet for the rear cooler of the compressor, wherein the drain outlet is opened and closed in conjunction with the opening and closing of the compressor. 4. The rear cooler drain discharge device according to claim 3, wherein the drain valve closes a drain discharge port when an unloader valve of the capacity control device closes an intake port. 5. A drain valve provided at a drain outlet of the drain tank to form a drain valve, and the solenoid valve detects a pressure in a receiver tank to which compressed air discharged from the compressor body is supplied. 5. The compressor according to claim 3, wherein the compressor is connected to a power supply via a pressure switch, and the operating pressure of the pressure switch is set to substantially the same pressure as the pressure in the receiver tank when an unloader valve closes an intake port. Rear cooler drain discharge device. 6. A drain valve provided with a solenoid valve at a drain outlet of the drain tank, wherein the solenoid valve is provided with a pressure switch for detecting a pressure in a suction chamber of a compressor body downstream of the displacement control device. 5. The rear cooler of the compressor according to claim 3, wherein the pressure switch is connected to a power supply, and the operating pressure of the pressure switch is set to substantially the same pressure as the pressure in the suction chamber when the unloader valve closes the suction port. Drain discharge device. 7. The capacity control device is a valve lift type in which an unloader valve connected to the shaft opens and closes an intake port by moving the shaft forward and backward, and the drain valve is operated in conjunction with the forward and backward movement of the shaft. The drain discharge device for a rear cooler of a compressor according to claim 3 or 4, further comprising a valve body that opens and closes the drain valve. 8. The butterfly control device according to claim 1, wherein the displacement control device is a butterfly type in which an unloader valve fixed to the shaft swings in the intake port by rotating the shaft to open and close the intake port. 5. The drain discharge device for a rear cooler of a compressor according to claim 3, further comprising a valve body that opens and closes the drain valve in conjunction with rotation of the compressor.