JPS5912192A - Oil supply stopping device for screw compressor - Google Patents

Abstract

PURPOSE:To reduce the amount of oil reserved in the compressor by a method wherein a valve, opened and closed by the variation of the secondary side pressure of a suction choking valve, is provided on the way of an oil supplying pipeline to stop instantaneously the supply of oil upon stopping the compressor. CONSTITUTION:Upon starting the compressor, air in an oil separator 2 is flowed reversely into the secondary side 13 of the suction choking valve 5 and the pressure of the secondary side 13 of the valve 5 is increased. The pressure of the secondary side 13 of the valve 5 is introduced into the main body 24 of a stop valve to push a valve body 26 by the pressure and the force of a spring 28 for the stop valve 23 and an oil path 25 in the stop valve 23 is closed. As a result, the supply of the oil from the oil supplying pipeline to the main body 1 of the compressor is interrupted instantaneously and surely and the amount of oil reserved in the compressor may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil supply stop device for a screw compressor, in particular, it is capable of instantly and reliably stopping oil supply when the compressor is stopped.
The present invention relates to a screw compressor oil supply stop device suitable for reducing startup load.

In a screw compressor, the pressure inside the oil separator is high during compressor operation, so the oil separated by the oil separator is pushed out in the direction of the oil supply pipe, and is sent to the compressor body through the oil supply system, which includes the oil supply pipe and check valve. Oil is supplied. Also, when the compressor stops, the air in the oil separator is gradually released to atmospheric pressure, but if oil is supplied to the compressor body during this release period, the compressor will be filled with oil and regenerated. At startup, this oil acts as resistance and increases the load. Therefore, it is necessary to stop the oil supply when the compressor is stopped.

As shown in FIG. 1, a conventional oil supply stop device when a compressor is stopped has an oil stop solenoid valve 19 and a check valve 2 in a pipe 18 connecting an oil separator 2 and the downstream side of an oil supply pipe 4.
0, and a check valve 21 is provided on the upstream side of the connection portion of the power distribution 18 in the oil supply pipe 4.

In this conventional oil supply stop device, when the compressor is stopped, the oil stop solenoid valve 19 opens, and the air released by the oil separator 2 is introduced into the downstream side of the oil supply pipe 4 through the pipe 18. A check valve 21 provided in the fuel tank is operated to stop oil supply.

However, the conventional oil supply stop device has an oil stop electric weight valve 19.
and two check valves 20 and 21 are required, so there is a disadvantage that an increase in cost is unavoidable, and there is a disadvantage that malfunctions are likely to occur.

An object of the present invention is to provide an oil supply stop device for a screw compressor that can instantly and reliably stop the supply of oil to the compressor body when the compressor is stopped, and that can also stop the supply of oil using a single valve. .

A feature of the present invention is that a valve that opens and closes depending on changes in the pressure on the secondary side of the suction throttle valve is provided in the middle of the oil supply pipe, and with this configuration, the above object can be reliably achieved. is.

Hereinafter, the present invention will be explained based on the drawings.

Fig. 2 shows a screw compressor and an embodiment of the refueling stop device of the present invention, and Fig. 3 shows a shutoff valve in the refueling stop device of the present invention that opens and closes according to changes in the pressure on the secondary side of the suction throttle valve. An example of a valve is shown.

As shown in FIG. 2, the screw compressor includes a compressor body 1, an oil separator 2, an oil supply pipe 4, a suction throttle valve 5, a secondary side 13 of the suction throttle valve 5, and an upper chamber of a piston 9. 10, a three-way solenoid valve 15 provided in the pipe 14, a pipe 16 connecting the oil separator 2 and the lower chamber 11 of the piston 9 of the suction throttle valve 5, and a pressure provided in the pipe 16. A regulating valve 17 is provided.

The suction throttle valve 5 is configured to bias the throttle valve body 6, the air suction lower, the valve body 8, the piston 9 for valve operation, the upper and lower chambers 10, 11 of the piston 9, and the valve body 8 in a direction to close them. It has a spring 12. This suction throttle valve 5 is
When the compressor is started, the valve body 8 is closed by the force of the spring 12, and when the valve body 8 is closed, the pressure on the secondary side 13 becomes a vacuum state, and the vacuum pressure is transferred to the upper part of the piston 9 through the piping 14 and the three-way solenoid valve 15. This vacuum pressure closes the valve body 8 even more tightly, making it possible to start the compressor in an unloaded state. 11, the pressure inside the oil separator 2 is introduced, the opening degree of the valve body 8 is adjusted, and the capacity is controlled.

On the other hand, as shown in FIG. 2, the refueling stop device is connected to a pipe 14 connecting the secondary side 13 of the suction throttle valve 5 and the upper chamber 10 of the piston 9, and is guided to the downstream part of the refueling pipe 4. A cutoff valve 23 is provided between the piping 22 and the downstream portion of the oil supply piping 4.

As shown in FIG. 3, the cutoff valve 23 includes a cutoff valve main body 24, an oil passage 25 formed at a substantially right angle extending from one end of the cutoff valve main body 24 through the interior to one side, and a cutoff valve. Valve body 26 inserted into main body 24 via 01J ring 27
, a spring 28 that urges the valve body 26 in the closing direction, a pressure introduction hole 30 that communicates with the inside of the shutoff valve body 24, and is attached to the other end of the shutoff valve body 24 by sandwiching a gasket 31. The spring receiver is provided with a member 29. Further, as shown in FIGS. 2 and 3, this shutoff valve 23 is connected to the downstream part of the refueling pipe 4 via boat A and boat B, and is connected to the pipe 22 via boat C. When the compressor is stopped, the pipe 14 is connected from the secondary side 13 of the suction throttle valve 5.
→ Piping 22 → Boat C → High pressure is introduced through the pressure introduction hole 30, the valve body 26 is closed by this pressure, and when the compressor is started, the vacuum pressure on the secondary side 13 of the suction throttle valve 5 is passed through the path. This vacuum pressure causes the valve body 26 to open against the force of the spring 28, and the pressure on the boat C side, which becomes atmospheric pressure during compressor operation, and port A, which is close to the discharge air pressure of the compressor.
The valve body 26 is pushed open by the pressure difference between the side pressure and the side pressure.

Note that in FIG. 1 showing the prior art and FIG. 2 showing an embodiment of the present invention, the same members are given the same reference numerals and explained.

The refueling stop device of the above embodiment operates as follows in relation to the operating mode of the screw compressor.

That is, when the compressor is started, the suction throttle valve 5 is fully closed, so the pressure on the secondary side 13 of the suction throttle valve 5 becomes a vacuum state, and the vacuum pressure passes through the piping 14 and the three-way solenoid valve 15. The vacuum pressure Due to this, the valve body 26 of the shutoff valve 23 is connected to the spring 28.
It is opened by overcoming the power of. Therefore, the oil 3 in the oil separator 2 is transferred from the oil supply pipe 4-→boat A→shutoff valve 23.
The oil is supplied to the compressor main body 1 through the oil passage 25 in the interior → B).

During operation of the compressor, the pressure inside the oil separator 2 is high, so the oil 3 inside the oil separator 2 is pushed out, and the oil 3 flows into the oil supply pipe 4. While the pressure on the boat C side of the shutoff valve 23 is atmospheric pressure, the pressure on the port 1-A side is close to the discharge air pressure of the compressor. Body 26 is pushed open and oil 3
is supplied to the compressor main body 1 from the oil supply pipe 4 through the above-mentioned route.

Then, when the compressor is stopped, the secondary side 1 of the suction throttle valve 5 is
3, the air inside the oil separator 2 flows backward, and the pressure on the secondary side 13 of the suction throttle valve 5 increases.

The pressure on the secondary side 13 of the suction throttle valve 5 is transmitted through the pipe 14 → pipe 22 → Bow)C → pressure introduction hole 30 to the shutoff valve main body 2.
4, the valve body 26 is pushed by this pressure and the force of the spring 28 of the cutoff valve 23, and the oil passage 25 in the cutoff valve 23 is closed. As a result, it becomes possible to instantly and reliably cut off the oil supply from the oil supply pipe 4 to the compressor body 1, thereby reducing the amount of oil accumulated inside the compressor and reducing the load when restarting. be able to.

In the present invention, the structure of the cutoff valve, which is a valve that opens and closes according to changes in the pressure on the secondary side 13 of the suction throttle valve 5, is not limited to the illustrated embodiment, and may be any structure as long as it has the desired function.

The present invention has the above-described configuration 1.According to the present invention, a valve is provided in the middle of the oil supply piping and is operated to open and close depending on the change in the pressure on the secondary side of the suction throttle valve, and the operation of the valve causes compression. Since oil supply can be stopped instantaneously and reliably when the machine is stopped, the amount of oil stagnation inside the compressor can be reduced, which has the effect of reducing the load upon restart.

Furthermore, whereas the conventional device uses an oil stop solenoid valve and two check valves, the present invention uses a single valve to stop the oil.
Since there is no need to use an expensive oil stop solenoid valve, there is an effect of significantly reducing costs, and there is also an effect of preventing troubles due to malfunctions.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional device, Fig. 2 is a system diagram showing a screw compressor and an embodiment of the refueling stop device of the present invention, and Fig. 3 is a suction throttle valve that opens and closes according to changes in the pressure on the secondary side. FIG. 3 is an enlarged vertical cross-sectional view of a shutoff valve as a valve. 1... Compressor body, 2... Oil separator, 3...
...Oil in the oil separator, 4...Oil supply piping, 5.
... Suction throttle valve, 13... Secondary side of the suction throttle valve, 14
...Piping connecting the secondary side of the suction throttle valve and the upper chamber of the piston, 15...Three-way solenoid valve, 16...Piping connecting the oil separator and the lower chamber of the piston of the suction throttle valve, 1
7... Pressure adjustment valve, 22... Piping connected to the piping connecting the secondary side of the suction throttle valve and the upper chamber of the piston, 23
...A shutoff valve is a valve that opens and closes depending on changes in the suction throttle valve. )・〈 Figure 1 Figure Z Figure J

Claims (1)

[Claims] The compressor body, the suction throttle valve for capacity control, the three-way solenoid valve that operates the suction throttle valve when starting the compressor, and the differential pressure between the pressure inside the oil separator and the pressure inside the compressor. In a screw compressor equipped with an oil supply pipe for supplying oil to the main body of the compressor, a valve is provided in the middle of the oil supply pipe that opens and closes according to changes in the pressure on the secondary side of the suction valve. Features: Refueling stop device for screw compressors.