JPH0213759Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a screw compressor, and more particularly, to an oil-cooled screw compressor with an automatic start/stop type.

(Prior Art) Conventionally, as this type of screw type compressor, the one shown in FIG. 2 is known. That is, in the figure, 1 is an oil-cooled screw type compressor body (hereinafter referred to as the compressor body) with an automatic start/stop type, which sucks gas from a suction filter 7 and receives cooling oil from a circulation pipe a. After the mixed medium of gas and oil is compressed, it is discharged to the receiver tank 3 through a pipe b provided with a check valve 2. After the compressed mixed medium is separated into compressed gas and cooling oil in the receiver tank 3, the compressed gas is supplied to a gas consumption point (not shown) from pipe c, while the separated and recovered cooling oil is circulated through pipe c. The oil is guided to the oil cooler 4 by a, cooled, and supplied to the compressor main body 1 for circulation and reuse.

In addition, the pressure of the compressed gas is detected by the pressure detector 5 installed in the pipe c, and when the consumption of compressed gas decreases and the pressure exceeds the upper limit of the predetermined pressure, the compressor is activated. At the same time as stopping the motor 6, the solenoid valve 8 provided in the circulation pipe a is closed, stopping the supply of cooling oil to the compressor body, and further increasing the consumption of compressed gas and causing its pressure to be below the lower limit pressure. If the compressor drive motor 6
It is configured to open the solenoid valve 8 at the same time as restarting the engine, thereby saving energy.

(Problem to be solved by the invention) By the way, in the screw type compressor, when the pressure of the compressed gas exceeds the upper limit pressure and the operation is stopped, the pipes on the inlet side of the compressor main body 1 and the check valve 2 The compressed gas remaining in path b is released to the atmosphere through the suction filter 7, but the cooling oil mixed in the compressed gas is not released to the atmosphere together with the compressed gas, but accumulates in the compressor body 1, so that it will not be released into the air when restarted. However, liquid compression caused deformation of the rotor, damage to the casing, or abnormal noise, and in some cases, it was impossible to start.

The present invention has been made in view of the above-mentioned drawbacks of the conventional art, and an object of the present invention is to provide a screw type compressor that prevents oil from accumulating in the compressor body 1 when the operation is stopped, and that can be restarted smoothly. shall be.

(Means for Solving the Problems) The screw type compressor according to the present invention has a delay that stops the compressor drive motor after a predetermined time delay when a stop signal is issued from the pressure detector to the compressor drive motor. By providing a means, the compressor body is driven for a while even after the supply of cooling oil to the compressor body is stopped, and residual oil is driven downstream of the check valve, thereby preventing oil from accumulating in the compressor body. It is something.

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

FIG. 1 shows a screw type compressor according to the present invention, in which a delay means 9 such as a timer is provided in a circuit for starting and stopping a compressor drive motor 6 using a pressure detector 5 shown in FIG. The other parts are substantially the same as the screw type compressor shown in FIG. 2, and corresponding parts are given the same numbers and explanations will be omitted.

(Function) This delay means 9 stops the stop signal sent from the pressure detector 5 to the compressor drive motor 6 for a certain period of time (several seconds), and stops the compressor drive motor 6 for a while after the solenoid valve 8 is closed. It is a delay. Therefore, due to the difference between the closing signal issued to the solenoid valve 8 and the stop signal to the compressor drive motor 6, even after the solenoid valve 8 is closed and the supply of cooling oil is stopped, the compressor main body 1 will be operated for a certain period of time. Therefore, the cooling oil mixed with the compressed gas in the compressor body 1 and in the check valve 2 inlet side pipe b passes through the check valve 2 to the receiver tank 3.
Therefore, cooling oil does not accumulate inside the compressor main body 1 after the operation is stopped.

(Effect of the invention) Therefore, according to the invention, since cooling oil does not accumulate inside the compressor body after the operation is stopped, operation can be started smoothly without causing liquid compression when restarting the screw type compressor. It has this effect.

In the above embodiment of the present invention, the pressure detector 5 is installed in the pipe c, but it may be installed in the upper part of the main body of the receiver tank 3 as long as it is downstream from the check valve 2.

Furthermore, the delay means for delaying the stop signal from the pressure detector, which is a feature of the present invention, includes mechanical delay means as well as electrical delay circuits such as timers.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a screw type compressor according to the present invention, and FIG. 2 is a system diagram of a conventional screw type compressor. DESCRIPTION OF SYMBOLS 1... Compressor body, 2... Check valve, 3... Receiver tank, 4... Oil cooler, 5... Pressure detector, 6... Compressor drive motor, 8... Solenoid valve, 9... Delay means, a...
Circulation duct.

Claims (1)

[Scope of utility model registration request] The oil-mixed compressed gas discharged from the compressor body is introduced into the receiver tank via the check valve, and after the oil and compressed gas are separated in this receiver tank, the oil is supplied to the compressor body through an oil cooler and circulated. On the other hand, a screwdriver is configured to open and close a solenoid valve provided in the oil circulation path at the same time as starting and stopping the compressor drive motor based on a detection signal from a pressure detector provided downstream from the check valve. A screw type compressor, characterized in that the circuit for starting and stopping the compressor drive motor in response to the detection signal is provided with a delay means for delaying the stop signal for a predetermined period of time to stop the compressor drive motor.