JPH04124494A - Oil smoke removing device for oil-free screw compressor - Google Patents

Abstract

PURPOSE:To prevent the outflow of oil drops from a safety valve even at the stop time of a compressor by operating a solenoid valve for performing the on-off operation of compressed air to an ejector in such a way as to continue the flow of air for a few seconds after the stop of the compressor. CONSTITUTION:The on-off operation of a solenoid valve 24 is performed by a circuit using an off-delay timer 43 so as to open an air passage by the solenoid valve simultaneously with the start of a compressor and to close the air passage in a few seconds after the stop of the compressor. An ejector is thereby continued to act until the complete stop of air leak generated due to the inertial rotation of the compressor for a few seconds after the stop of the compressor, and this dissolves the possibility of a relief valve being opened after the stop, causing the leak of oil drops from there.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for removing oil smoke from the gear case exhaust of an oil-free screw compressor.

[Conventional technology]

As shown in Figure 1, the conventional device is equipped with a solenoid valve 24, but it opens and closes at the same time as the compressor starts and stops, so even after the compressor stops, the motor continues to operate for several seconds. As the gear case rotates due to inertia and a small amount of air and oil mist continue to leak from the gear case exhaust pipe, the internal pressure of the gear case increases, causing the safety valve 40 to temporarily open.

As a result, oil droplets adhering to the inside of the safety valve may flow out of the valve body together with air when the valve is opened.

[Problem to be solved by the invention]

An object of the present invention is to provide a mechanism that prevents oil droplets from flowing out from a safety valve even when the compressor is stopped, or prevents oil droplets from dripping outside the machine even if they do leak.

[Means to solve the problem]

In order to achieve the above object, the present invention uses a solenoid valve for turning compressed air on and off to the ejector so that air continues to flow for several seconds after the compressor is stopped.

[Effect]

Since the solenoid valve continues to flow compressed air to the ejector for several seconds after the compressor stops, the phenomenon of the internal pressure of the gear case increasing after the compressor stops does not occur, and oil droplets do not flow out.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

A container 15 containing a filter element 14 for separating oil mist is attached to the gear case exhaust, and the pressure in the container 15 on the secondary side of the filter element 14 is maintained at negative pressure by exhausting with a vacuum ejector 16 attached to the container. . As a result, even if the filter element shows an increase in passing pressure loss due to an oil film, the internal pressure in the gear case becomes positive, allowing oil mist to be separated and removed without reducing the reliability of the compressor shaft sealing device. .

On the other hand, in order to avoid wasting air when the compressor is stopped, the solenoid valve 24 opens the air passage when the compressor is started, and closes the air passage several seconds after the compressor stops. Then, the solenoid valve is turned on and off by a circuit using an off-delay timer 43. As a result, after the compressor stops, the ejector 16 continues to rotate for several seconds until the leakage air generated by the compressor continues to rotate due to inertia is completely eliminated.
This problem occurred with conventional technology because the system can continue to operate.

After stopping, the relief valve opens, eliminating the possibility of oil droplets leaking from there.

FIG. 2 shows a second embodiment of the present invention, in which a relief valve 40 is assembled so that its operating axis 43 is oriented vertically. Furthermore, the valve plate of the relief valve is installed in a box 44 that encloses the valve plate, and even when the relief valve overcomes the weak spring 42 and opens, the oil droplets adhering to the inside of the valve plate 41 are removed. No leakage to the outside due to its own weight.

FIG. 3 shows a third embodiment of the present invention, in which the operating axis of the relief valve is horizontal, an oil sump 50 is provided at the bottom, and a small hole 5 communicating with the primary side of the filter element is provided at the bottom of the oil sump 50.
1 is provided. The diameter of the small hole must be large enough to suck in a small amount of oil, but small enough to prevent ejector loss due to air being sucked through the hole.

According to this embodiment, even if oil droplets flow out from the relief valve, they will accumulate at the bottom of the oil sump 50 and will be further sucked into the negative pressure on the primary side of the filter element generated by the operation of the oil smoke removal device. Spilled oil is automatically collected.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the generation of oil droplets that may flow out from the relief valve.

[Brief explanation of drawings]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a system diagram of a second embodiment of the invention, Fig. 3 is a system diagram of a third embodiment of the invention, and Fig. 4 is a system diagram of a third embodiment of the invention. It is a system diagram of a prior art. ]-... Oil-free screw compressor, 2... Gear case, 3... Speed-up gear, 4... Oil pump,
14... Filter element, 15... Filter container, 16... Ejector, 17... Air filter, 18
... Pressure reducing valve, 19... Oil recovery pipe, 20... Pressure sensor, 22... Oil sump chamber, 24... Solenoid valve, 40...
...Relief valve, 41...Valve plate, 42...Spring, 4
3... Off-delay timer contact, 43... Valve stem, 4
4... Valve box, 50... Oil sump. Horse 1 Illustration 2 Ward 3

Claims (1)

[Claims] 1. A gear case containing a gear that drives the rotor shaft of the oil-free screw compressor is integrally attached to the oil-free screw compressor, and the oil-free screw compressor is supplied with oil from within the gear case to perform the oil-free screw compression. The exhaust oil and leaked gas from the machine are discharged into the gear case, an exhaust pipe is connected to the gear case, a filter container containing a filter element for oil mist separation is connected to the exhaust pipe, and the inside of the filter container is In the oil-free screw compressor device, a vacuum eject inlet for making the pressure in the secondary chamber of the filter element negative pressure is connected to the secondary chamber of the filter element in the filter container, The oil-free screw compressor is characterized by being provided with a valve that starts supplying compressed air to the ejector at the same time as the machine starts operating, and stops supplying the compressed air several seconds after the oil-free screw compressor stops. Machine oil smoke removal device.