JPS6137473B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an oil-fed compressor.

(Prior Art) An oil-fed compressor, such as a screw compressor, includes a compressor body driven by an electric motor, and a capacity adjustment valve (gas inflow adjustment valve) that adjusts the amount of air sucked into the compressor body. , an oil tank that separates oil from the air compressed by the compressor body, an oil separator that separates oil mist from the air that has passed through the oil tank, and an oil separator that cools and compresses the oil in the oil tank. It consists of an oil cooler that injects oil into the main body.
When the compressor main body is driven, air is sucked into the compressor main body via the capacity adjustment valve, where it is compressed and flows into the oil tank, where the oil content in the compressed air is removed. The compressed air from the oil tank is completely purified by removing mist of oil in an oil separator, and when the discharge valve is opened, the purified compressed air is supplied to external equipment. The oil in the oil tank is supplied to the oil cooler by the internal pressure of the oil tank and is cooled, and after being cooled, it is injected into the compressor main body to provide lubrication and maintain airtightness.

(Problem to be solved by the invention) When the discharge valve is closed, the pressure in the oil tank and oil separator increases, and if the compressor body is stopped in this state, the pressure difference between the capacity adjustment valve and the oil tank increases. As a result, the compressed air in the oil tank flows back into the compressor body, and at the same time, the oil liquid in the oil tank is also injected into the compressor body due to the tank internal pressure, causing damage to the inside of the capacity adjustment valve, the oil tank, and the oil separator. The internal pressure is the same. If you restart the compressor in this state,
The compressor body did not rotate, and the electric motor was burnt out. The reason for this is thought to be that the pressure balance inside the compressor collapses, and the pressure on the suction side becomes lower than the oil tank pressure, causing oil to be injected, and on the discharge side, oil is compressed, making it impossible to start. It is being said.

By the way, in such a case, if the pressure inside the oil separator is lowered when the compressor main body is stopped, the compressor main body can be rotated. Conventionally, with this method, all of the compressed air in the oil separator was released, which resulted in the problem of wasting a lot of energy.Furthermore, it required manual labor each time to restart the oil separator. The disadvantage was that it required

Further, during unloading operation, pressure fluctuations in the suction side passage become large, so there is a problem in that noise due to pressure changes of the suction air increases, resulting in so-called unloading noise.

Possible ways to solve this problem include adding an air release valve device to reduce the pressure of the compressed air on the discharge side after the end of operation, and special means to prevent unloading noise. However, attaching a plurality of valve devices and the like to the compressor main body increases the number of parts and requires a large installation space, which is not practically preferable.

Note that the capacity adjustment valve in this type of compressor introduces discharge side pressure, and as the pressure increases, the valve opening amount becomes smaller. For example, during unload operation, the pressure in the discharge side path is high. Therefore, the valve opening degree becomes smaller, and as a result, the degree of vacuum in the internal chamber of the capacity adjustment valve increases.

The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to guide the internal pressure of the gas inflow amount regulating valve in the suction side path to provide an air release function and a gas return function to the oil spout. By adding a valve device with a pressure adjustment mechanism, when the compressor is stopped, the pressure inside the oil separator is reduced to facilitate restarting, and when the compressor is unloaded, the pressure gas in the discharge side passage is reduced. An object of the present invention is to provide an oil-cooled compressor in which an oil-cooled compressor is introduced into an oil spout to reduce unloading noise.

(Means for solving the problem) Specific means of the present invention for achieving this objective are as follows:
A signal pressure introduction passage 23 connected to the gas inflow adjustment valve 5 provided on the suction side of the compressor body 1, and a discharge side passage 30 connected to the oil separator 4 provided on the discharge side of the compressor body 1. and an air discharge passage 31 communicating with the atmosphere.
, a valve body 27 that receives the internal pressure of the signal pressure introduction passage 23 at one end and operates to communicate the discharge side passage 30 with the air discharge passage 31; and an operating pressure adjustment spring that biases the valve body 27 toward the one end. The valve device 8 is provided with a valve device 8 having a valve body 28 during an unload operation.
This is an oil-cooled compressor in which a constriction part 7 is moved toward one end and communicates with the discharge side passage 30, and the constriction part 36 is connected to the oil spout 1a of the compressor main body 1.

(Function) With the above configuration, when the compressor main body 1 is stopped while the internal pressure of the oil separator 4 is high, the pressure gas from the oil separator 4 side, that is, the discharge side, flows back into the suction side path. Chamber 5c of gas inflow adjustment valve 5
The internal pressure of the oil separator 4 is introduced into the signal pressure introduction passage 23. This internal pressure causes the valve body 27 to move axially in the other end direction against the operating pressure adjustment spring 28.
Thereby, the discharge side passage 30 communicates with the air discharge passage 31. For this reason, the discharge side passage 30 of the compressor main body 1
The pressure gas inside is released into the atmosphere from the air discharge passage 31, and the internal pressure of the discharge side passage 30, that is, the internal pressure of the oil separator 4 is reduced. When the internal pressure of the oil separator 4 drops to the set pressure (pressure P ₁ in FIG. 3), the spring 28
Due to the force, the valve body 27 is axially moved in the direction of one end thereof,
Communication between the discharge side passage 30 and the air discharge passage 31 is cut off. Therefore, the release of the pressure gas in the discharge side passage 30 is stopped.

Therefore, by adjusting the set pressure of the operating pressure adjustment spring 28 that biases the valve body 27 to an appropriate pressure so that the compressor can be restarted, only the minimum necessary amount of pressurized gas can be released. This makes it possible to easily restart the compressor after it has been stopped without causing problems such as burnout to the electric motor.

On the other hand, when the compressor body 1 is in operation, the compressed gas is sent to the load side via the oil separator 4 and used, and the oil separated in the oil tank 3 is compressed from the oil spout 1a. It is injected into the machine body 1.

When the amount of pressure gas used on the load side decreases, the internal pressure of the oil separator 4 and the oil tank 3 increases, and this oil pressure is transferred to the back pressure chamber 5 of the gas inflow adjustment valve 5 of the compressor main body 1.
d to close the valve. Switching to so-called unload operation.

During this unloading operation, the degree of vacuum in the chamber 5c of the gas inflow adjustment valve 5 increases, so the valve body 27 of the valve device 8 is axially moved toward one end thereof by the force of the operating pressure adjustment spring 28, and the discharge side The passage 30 is the valve device 8
It communicates with one end of the constriction part 36 of. This aperture part 36
Since the other end is connected to the oil spout 1a of the compressor main body 1, the pressure gas in the discharge side passage 30 is introduced into the oil spout 1a.

Therefore, the pressure gas in the oil separator 4 is partially throttled and then flows through the oil spout 1a to the compressor main body 1.
Since the suction gas is injected into the air, the noise generated by the suction gas during unloading operation is effectively reduced.

In this way, the compressor of the present invention realizes the above-described ease of restart and prevention of unloading noise by simply adding one valve device. Therefore, compared to a system in which a valve device for guiding pressure gas to the oil spout and a special means such as a valve device for releasing air are installed separately, the configuration is simpler, smaller, cheaper, and more practical. It increases the value of the product.

Further, in the present invention, the release of the pressure gas from the oil separator 4 to the atmosphere is automatically stopped when the pressure of the gas flowing back into the gas inflow control valve 5 reaches a set value that allows restart. Ru. Therefore, since the gas pressure does not drop more than necessary, oil injection to the compressor main body 1 can be started immediately when the compressor is restarted. Therefore, even if the oil separator 4 or oil tank 3 has a large capacity, oil injection can be performed immediately, so that the internal pressure of the oil separator 4 or oil tank 3 can be reduced by oil injection during restart operation. There is no need to carry out a trial run to raise the required pressure to a possible level.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a screw compressor as an example of an oil-fed compressor. 1 is a compressor main body driven by an electric motor 2;
An oil tank 3 and an oil separator 4 are connected to the discharge side of the compressor, and a capacity adjustment valve 5 is connected to the suction side of the compressor main body 1. Capacity adjustment valve 5 is oil tank 3
The opening/closing operation of the valve body 5b is controlled by the operation of the pressure oil inside and the spring 5a, and the capacity of air sucked into the compressor main body 1 is adjusted. An oil cooler 6 is connected to the oil tank 3, and the oil cooled by the oil cooler 6 is injected into the compressor main body 1. 7 is a discharge valve for supplying compressed air to external equipment.

8 is a suction side system of the compressor main body 1 (capacity adjustment valve 5
The pressure in the suction side line causes the discharge side line (downstream side from the discharge port of the compressor body 1) to be connected to the air inlet of the compressor body 1. The valve device 8, which is a valve device for reducing the pressure of a system (system formed in a system), will be explained in detail with reference to FIG.

A cylinder 22 is formed in the main body 10 of the valve device 8, and a port 2 is connected to one end of the cylinder 22.
3 is facing, and the spring receiver 24 is attached to the other end from the outside.
A threaded portion 25 is provided for screwing together. 26
This is a lock nut that fixes the spring receiver 24 to the main body 10.

A spool valve 27 is slidably fitted into the cylinder 22, and the spool valve 27 is attached to the spring receiver 2.
It is energized by a spring 28 that is in elastic contact with the port 4, and is in elastic contact with a spring 29 that is disposed on the port 23 side.
Two ports 30 and 31 face the cylinder 22, and as the spool valve 27 moves upward against the spring 28, the first piston 27a and the second piston 27
It communicates with the cylinder 22 through a chamber 22a defined by the cylinder 22 and the cylinder 22a. 32 is the cylinder 22 and piston 2
This is a seal ring that prevents leakage between the parts 7a and 27b. The chamber 22b containing the spring 28 communicates with the atmosphere through a gap 39, and is configured so as not to block the movement of the spool valve 27.
Further, a port 33 is provided in the cylinder 22, and the spool valve 27 is connected to the spring 29.
As it moves downward against the pressure, it communicates with the port 30 via the chamber 22a.

The port 30 is connected to the oil separator 4 via a pipe 34, the port 31 is opened to the atmosphere, the port 33 is connected to the oil spout 1a of the compressor body 1 via a pipe 35, and the port 23 is connected to the chamber 5c of the capacity adjustment valve 5.

(Operation of the embodiment) The operation of the screw compressor according to the above configuration will be explained. Here, the voltage applied to motor 2 is
Assume that V ₁ is constant.

When the motor 2 rotates, the compressor body 1 is driven, and the valve body 5 of the capacity adjustment valve 5 adjusts the amount of gas inflow.
b is opened, and air is sucked into the compressor main body 1 through the chamber 5c. The sucked air is mixed with oil and compressed within the compressor body 1. Next, this compressed air is discharged into the oil tank 3 to separate the oil, and then to the next oil separator 4.
Separate the mist of oil. Thereafter, the compressed air is sent from the discharge valve 7 to an external device (not shown) on the load side for use. On the other hand, the oil in the oil tank 3 is sent to an oil cooler 6, cooled, and injected into the compressor main body 1 from the oil spout 1a.

When the compressor main body 1 is operating at its rated value or when the oil separator 4 is at atmospheric pressure and is stopped, the valve device 8 is in the state shown in FIG. 4.

That is, for example, when the compressor main body 1 is driven, the pressure inside the oil separator 4 is guided to the chamber 22a, but since the piston 27a and piston 27b of the spool valve 27 have the same diameter and the same pressure receiving area, the spool valve 27 has the same diameter and the same pressure receiving area. The axial forces applied to valve 27 are balanced.

Further, the chamber 5c of the capacity adjustment valve 5 is part of the suction passage of the compressor main body 1, and the port 23 side is at atmospheric pressure, and the chamber 22b side is also at atmospheric pressure. Therefore, the spool valve 27 is in the state shown in FIG. 4, and the port 30 is not communicating with the ports 27, 33.

Next, when the operation is stopped (however, the oil separator 4 is set to P ₁ or higher in Fig. 3), the pressure in the chamber 5c becomes equal to the pressure in the oil separator 4, so the pressure at ports 23 and 30 increases. are equal and greater than or equal to P ₁ . room 2
2b communicates with the atmosphere through the gap 39 in the spring receiver 24, so the spool valve 27 moves upward in the figure while compressing the spring 28 due to the pressure difference between the port 23 and the chamber 22b. state, the ports 30 and 31 communicate through the chamber 22a,
Compressed air in the oil separator 4 is released to the atmosphere through a port 31. As the discharge progresses, the pressure inside the oil separator 4 increases.
When P ₁ is reached, chamber 22a also becomes P ₁ , so port 2
The pressure at step 3 also becomes _P1 , and the spool valve 27 is returned downward by the preset spring load of the spring 28.
The port 31 is closed to stop air release. As is clear from FIG. 3, at this pressure P ₁ , startup is possible, and when the compressor main body 1 is driven again, the oil separator 4
Since the pressure at _P1 is such that it can be driven again, the compressor main body 1 is driven.

When the compressor body 1 is started, the pressure in the chamber 22a becomes atmospheric again, so that the valve device 8 returns to the state shown in FIG. 4. Further, the spring force of the spring 28 can be adjusted by the spring receiver 24, and the set pressure in the compressor can be adjusted.
It becomes possible to adjust changes in _P1 , variations in the spring force of the spring 28, etc.

When the amount of air used on the load side decreases to a predetermined value or less while the compressor main body 1 is being driven, the pressure in the oil tank 3 and the oil separator 4 increases, and the oil pressure in the oil tank 3 also increases. This oil pressure is guided to the capacity adjustment valve 5 through the pipe 40, closes the valve body 5b, and switches to unload operation.

At this time, the degree of vacuum in the chamber 5c of the capacity adjustment valve 5 increases, and the spring 29 is compressed by the differential pressure between the vacuum pressure in the chamber 5c and the atmospheric pressure in the chamber 22b, and the spool valve 27
is descending. By lowering the spool valve 27, the port 30 communicates with the throttle 36 through the chamber 22a and the gap between the spool valve 27 and the cylinder 22.
Therefore, a part of the compressed air in the oil separator 4 is
When passing through the gap and the throttle 36, the compressed air is depressurized by an appropriate amount, and the decompressed compressed air is guided to the oil spout 1a of the compressor body 1. As a result, a portion of the compressed air in the oil separator 4 is reduced in pressure and injected into the compressor main body 1 from the oil spout 1a, thereby reducing noise during unloading operation.
In this case, the port 31 is closed by the spool valve 27 and does not communicate with the port 30. Fifth
The figure shows the state during this unloading operation.

In the embodiment, a pull ring 37 is attached to the spool valve 27, and the pressure in the discharge side path can be lowered by arbitrarily releasing air during or after the operation, for example.

In the embodiment, the invention is applied to a screw compressor, but the present invention is not limited to this, and any oil-cooled compressor may be used.

(Effects of the Invention) As described above, according to the present invention, by simply adjusting the spring 28, when the compressor main body 1 is stopped, an appropriate amount of pressurized gas in the oil separator 4 can be released. let me,
Since the pressure inside the oil separator 4 can be automatically lowered to the pressure at which the compressor main body 1 can be restarted, problems such as motor burnout will not occur.
The compressor main body 1 can be restarted more easily than in the past. In this case, it is not necessary to release all the pressurized gas in the oil separator 4 until it reaches atmospheric pressure, so energy waste can be avoided.

Furthermore, by stopping the release of pressurized gas at a pressure that is large enough to restart, oil injection from the jet port 1a can be immediately started at the time of restart. Therefore, even if the capacity of the oil tank 3 or the oil separator 4 is large, there is no need to operate the oil tank 3 or the oil separator 4 to increase the internal pressure as in the conventional case, and time loss can be eliminated accordingly.

During the unloading operation, the pressure gas on the discharge side is appropriately reduced in pressure by the throttle part 36 and introduced into the oil jet port 1a, so that it is possible to effectively prevent the generation of noise due to the intake gas during the unloading operation.

Furthermore, since the air release mechanism and the gas return mechanism to the oil spout 1a are combined in one valve device 8, compared to a case in which both of the above mechanisms are separately added to two valve devices. Therefore, it is advantageous in terms of installation space, piping work, manufacturing cost, etc., and has the unique effect of increasing practical use value.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a compressor according to the present invention;
Figures 4 and 5 are cross-sectional views of the valve device;
The figure is a starting characteristic diagram. 1... Compressor main body, 1a... Oil spout, 4...
Oil separator, 5... Capacity adjustment valve (gas inflow adjustment valve), 8... Valve device, 23... Port (signal pressure introduction passage), 27... Spool valve (valve body), 28...
...Spring for adjusting operating pressure, 30... Port (discharge side passage), 31... Port (discharge passage), 36... Throttle.

Claims (1)

[Claims] 1. Signal pressure introduction passage 23 connected to gas inflow adjustment valve 5 provided on the suction side of compressor main body 1
The internal pressure of the discharge side passage 30 connected to the oil separator 4 provided on the discharge side of the compressor main body 1, the air discharge passage 31 communicating with the atmosphere, and the signal pressure introduction passage 23 is controlled at one end surface. The discharge side passage 30
The valve device 8 includes a valve body 27 that communicates with the air discharge passage 31, and an operating pressure adjustment spring 28 that biases the valve body 27 toward one end thereof, and the valve device 8 includes: The valve body 2 during unloading operation.
7 is attached with a constriction part 36 that communicates with the discharge side passage 30 by moving toward one end thereof, and the constriction part 36 is connected to the oil spout 1a of the compressor main body 1.
An oil-cooled compressor characterized by being connected to.