JPH0599181A - Lubricating oil automatic recovery device for dry vacuum pump - Google Patents

Abstract

(57) [Summary] [Purpose] The lubricating oil replenishment time for the complete recovery of the oil mist that is mixed into the gas purged into the shaft seal of the pump and exhausted from the automatic lubricating oil recovery device for the dry vacuum pump. Significantly extended. [Structure] The purge gas exhaust pipe 18 is provided with oil mist recovery separators 19 and 20 at the front and rear stages in series,
The front separator 19 is stepped so that the attachment position is lower than the rear separator 20. Then, an oil recovery pipe 23 was connected between the bottom of the separator 19 at the preceding stage and the oil chamber 14. In addition, a solenoid valve 24 and a check valve 25 are provided between the bottom of the separator 20 at the rear stage and the suction port side pipe 16 of the oil supply pump 5.
And the oil recovery pipe 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil automatic recovery device for a dry vacuum pump used in a semiconductor manufacturing apparatus or the like.

[0002]

2. Description of the Related Art Many dry vacuum pumps used in the middle and low vacuum regions have been developed and sold in the last few years.
Although the method of purging the gas into the machine room is adopted as described in Japanese Patent No. 8992, the recovery of the oil mist is not discussed.

[0003]

In the above-mentioned prior art, since the lubricating oil is mixed in the exhausted purge gas and is discharged together, the lubricating oil is reduced, and it is necessary to replenish the lubricating oil after a certain time has elapsed. It was Lubricant recovery and replenishment work has been a cause of polluting the inside of the clean room, such as soiling the hands of workers and soiling the area around the vacuum pump with oil. Further, in order to replenish the lubricating oil, it is necessary to stop the vacuum pump, which leads to a reduction in the operating efficiency of the device, which is also a factor in reducing the productivity.

An object of the present invention is to provide an automatic lubricating oil recovery device capable of automatically recovering lubricating oil mixed in purge gas and discharged together, and further automatically supplying the recovered lubricating oil to the vacuum pump main body side. To do.

[0005]

In order to achieve the above object, two oil mist recovery separators are provided in series in the purge gas exhaust pipe, and the mounting position of the oil mist recovery separator at the front stage is lower than that of the oil mist recovery separator at the rear stage. I attached it with a step.

Then, a pipe was connected between the oil reservoir at the bottom of the oil mist recovery separator in the preceding stage and the oil chamber. Further, the oil sump at the bottom of the oil mist recovery separator at the latter stage and the suction port side of the oil supply pump were connected by piping via a solenoid valve and a check valve.

The structure of the oil mist recovery separator in the preceding stage is made cylindrical, and the tip of the intake side pipe is provided near the bottom surface in this cylindrical container, and the tip of the exhaust side pipe is provided near the top surface in the cylindrical container. Configured.

[0008]

The oil mixed in the gas purged from the oil chamber in the form of mist is accelerated in the intake side pipe until it enters the oil mist recovery separator at the preceding stage and collides with the bottom surface of the oil mist recovery separator. At the same time, the speed is rapidly reduced in the oil mist recovery separator, and most of the oil mist is recovered as oil drops. The oil collected as oil droplets is rarely carried away by the purge gas because the oil mist recovery separator at the front stage is located at a lower position than the oil mist recovery separator at the rear stage. It collects in the oil chamber from the bottom of the separator through the pipe connected to the oil chamber from the bottom of the separator.

On the other hand, a small amount of oil that cannot be recovered by the oil mist recovery separator in the previous stage is captured by the filter built in the oil mist recovery separator in the subsequent stage. The oil captured by the filter accumulates at the bottom of the oil mist recovery separator due to its own weight. Then, the oil accumulated at the bottom of the oil mist recovery separator is intermittently opened for several seconds by a solenoid valve installed between the suction port of the oil supply pump and the oil in the oil mist recovery separator gets into the oil supply pump due to the pressure difference. It acts to return.

The solenoid valve is controlled by setting the opening / closing time in advance on the starting board of the main body of the vacuum pump. According to the present invention, oil is hardly consumed in the oil chamber, and as a result, oil replenishment is not required, so that maintenance-free operation for a long time can be performed.

[0011]

Embodiment An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 2 is a rotor, 1 is a casing for housing a male rotor and a female rotor, and the rotor is rotatably supported by a discharge side bearing 3 and a suction side bearing 4. Both bearings are lubricated with oil, the discharge side bearing 3 is forcedly lubricated by an oil supply pump 5, and the suction side bearing 4 is splashed and oiled by a slinger 6. 7 is provided with a purge gas supply pipe 8 in the middle of the shaft seal to purge the inert gas so that the lubricating oil of the discharge side bearing 3 which is forcibly supplied with the discharge side shaft seal does not flow into the working chamber (rotor chamber). There is. Reference numeral 9 denotes a suction-side shaft seal, but oil is splashed to the suction-side bearing 4 so that the shaft seal is not purged with gas. Reference numeral 10 denotes a gear casing, which accommodates a speed increasing mechanism including a speed increasing gear 12 directly connected to a shaft end of a motor 11 and a timing gear 13 directly connected to a rotor shaft. An oil chamber 14 for lubricating the speed increasing gear 12, the timing gear 13, and the discharge side bearing 3 is provided in the lower portion of the gear casing 10, and an oil supply pump 5 supplies an oil supply pipe 15,
Each part is refueled via 16 and 17. Since a part of the purge gas supplied to the shaft seal flows into the gear casing 10, a purge gas exhaust pipe 18 for exhausting the purge gas is provided. When the vacuum pump is operated in the purge gas exhaust pipe 18, the refueling pump 5
The oil supplied to the discharge side bearing 3, the speed increasing gear 12 and the timing gear 13 is swirled and becomes mist-like gas and is exhausted together with the purge gas. However, in the prior art, this mist-like oil is not collected and is taken out of the machine. There was a problem that it was necessary to refuel frequently because it was drained.

Therefore, in the present invention, the purge gas exhaust pipe 1
Two oil mist recovery separators are provided in series in the system No. 8, and the oil mist recovery separator 19 in the front stage is mounted with a step so that the mounting position is lower than that of the oil mist recovery separator 20 in the rear stage. This is to prevent the oil droplets collected by the former-stage oil mist recovery separator 19 from being easily discharged together with the purge gas. The oil mist recovery separator 19 in the former stage is a cylindrical body 2
1. The purge gas exhaust pipe 18 is introduced into the inside of the main body 21, the tip of the purge gas exhaust pipe 18 is provided near the bottom surface of the main body 21, and the tip of the other purge gas exhaust pipe 22 is provided near the top surface of the main body 21. 14 and the oil recovery pipe 23
Connect with. The oil collected by the oil mist recovery separator 19 at the preceding stage and accumulated on the bottom surface is automatically recovered in the oil chamber 14 via the oil recovery pipe 23.

On the other hand, the oil mist recovery separator 20 in the latter stage has a filter for trapping the oil mist in the separator, and a small amount of oil mist that cannot be recovered by the oil mist recovery separator 19 in the former stage by this filter. Is collected and stored in the bottom of the oil mist recovery separator 20 in the rear stage. The bottom of the oil mist recovery separator 20 in the rear stage is connected to the suction side of the oil supply pump 5 via the solenoid valve 24, the check valve 25 and the oil recovery pipe 26. It is connected to the oil supply pipe 16. With this configuration, the oil stored in the bottom portion of the oil mist recovery separator 20 in the subsequent stage is sucked into the oil supply pump 5 due to the pressure difference due to the suction pressure of the oil supply pump 5 by intermittently opening the solenoid valve 24 for several seconds. As a result, oil will be recovered.
The check valve 25 is provided to prevent the reverse flow of oil when the pressure on the suction side of the oil supply pump 5 becomes higher than the pressure in the oil mist recovery separator 20 at the subsequent stage for some reason.

According to this embodiment, most of the oil mist mixed in the purge gas can be recovered by the oil mist recovery separators in the front and rear stages, so that the oil mist can be touched again without stopping the vacuum pump during operation. Long-term maintenance-free operation without
A great effect can be obtained in terms of usability.

[0015]

EFFECTS OF THE INVENTION According to the present invention, since the vacuum pump oil can be replenished for a long period of time, the usability is remarkably improved, and the troublesome refueling and draining work can be relieved to improve the operation efficiency and clean room. It has a great effect on environmental protection.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a screw type dry vacuum pump showing an embodiment of the present invention.

[Explanation of symbols]

5 ... Oil supply pump, 14 ... Oil chamber, 18 ... Purge gas exhaust pipe, 19 ... Pre-stage oil mist recovery separator, 20 ...
Oil mist recovery separator in the latter stage, 22 ... Purge gas exhaust pipe, 23 ... Oil recovery pipe, 24 ... Electromagnetic valve, 25 ... Check valve, 26 ... Oil recovery pipe.

Claims (3)

[Claims] 1. A dry vacuum pump using a gas purging system for sealing the shaft of an oil chamber and a working chamber, wherein two oil mist recovery separators are provided in series in a purge gas exhaust pipe from the oil chamber, and the oil mist of the preceding stage is provided. An automatic lubricating oil recovery device for a dry vacuum pump, characterized in that the recovery separator is provided with a step so that the installation position is lower than that of the oil mist recovery separator in the subsequent stage. 2. The oil sump at the bottom of the oil mist recovery separator at the preceding stage and the oil chamber are connected by a pipe, and the oil sump at the bottom of the oil mist recovery separator at the succeeding stage and the oil supply pump of claim 1. An automatic lubricating oil recovery device for dry vacuum pumps that connects the suction port with a pipe via a solenoid valve and a check valve. 3. The structure according to claim 1, wherein the oil mist recovery separator at the preceding stage has a cylindrical shape, the tip of the intake side pipe is near the bottom surface in the cylindrical container, and the tip of the exhaust side pipe is inside the cylindrical container. Oil mist recovery separators configured to be installed near the upper surface of each.