SU1285198A1 - Two-stage turbomolecular vacuum pump - Google Patents

Description

to

00

ate

about 00

The invention relates to vacuum technology, namely, to designs of turbomolecular vacuum pumps.

The aim of the invention is to improve the pumping performance by reducing backflows in the second stage zone, improving reliability by supplying lubricant to the supports when they are made in the form of rolling bearings, and also eliminating the ingress of lubricant vapor into the pumped-out volume.

FIG. 1 shows a pump, a longitudinal section; in fig. 2 shows section A-A in FIG. one.

The two-stage turbomolecular vacuum pump comprises a housing 1 with an inlet pipe 2, stator disks 3 of the first stage placed on the inner surface of the case I, and a second stage stator with channels on the inner surface having a reduced depth of the gas and rotor 4 with the shaft 5, mounted along the axis of the housing 1 on the supports 6, the rotor disks 7, the counter stator disks 3, and the cylindrical section 8, the second stage stator response, made as a set of rings 9 with notches 10 on the inner surface, mixed adjacent rings in the circumferential direction with the formation of labyrinth gaps that served as channels. The pump is equipped with an oil bath 11, the shaft 5 is made hollow and provided with channels 12 and 13, which are connected with the cavity 14 of the shaft 5

50

0

and connected to the supports 6, with the cavity 14 of the shaft 5 filled with a hygroscopic material and connected to the oil bath 11. The pump also additionally contains a nozzle 15 for filling in gas and gas, located on the housing 1 between the steps.

The pump works as follows.

The gas from the pumped volume enters the pump casing I through the inlet 2, from which, interacting with the blades of the rotor discs 7, is transferred to the second stage and through the channel formed by the recesses 10, further to the pump outlet. Performing a second stage stator in the form of rings 9 with notches 10 mixed in the circumferential direction of adjacent rings makes it possible to form a labyrinth gap between shaft 5 and the second stage stator, which largely prevents the back flow of the pump to the inlet, which provides an improvement pumping characteristics. The presence in the cavity 14 of the shaft 5 of a hygroscopic material contributes to a rational supply of lubricant to the supports 6, which determines the reliability of the pump as a whole due to good lubrication of the bearing assemblies. The penetration of lubricant vapors into the pumped volume prevents the supply of protective gas to the zone between the stages through the nozzle 15. The protective gas creates a directional flow to the side of pumping and prevents the vapor from penetrating into the zone of the first stage and beyond.

Claims (3)

1. TWO-STAGE TURBOMOLECULAR VACUUM PUMP, comprising a housing with an inlet pipe, stator disks of the first stage and a stator of the second stage with channels on the inner surface having a decreasing depth along the gas, and a rotor with a shaft installed along the axis of the housing on the bearings rotor disks, reciprocal stator disks, and a cylindrical section responding to the second stage stator, characterized in that, in order to improve pumping characteristics, the second stage stator is made in e set of rings with the recesses on the inner surface, offset relative to each other at adjacent rings in the circumferential direction to form a labyrinth gap serving channels. 2. The pump according to π. 1, characterized in that, in order to increase the reliability by supplying lubricant to the bearings when they are made in the form of rolling bearings, it is equipped with an oil bath, the shaft is hollow and provided with channels communicated with the shaft cavity and connected to the bearings, the shaft cavity being filled hygroscopic material and communicated with an oil bath. 3. The pump according to and. 2, characterized in that in order to prevent the ingress of lubricant vapor into the pumped-out volume, it further comprises a protective gas inlet nozzle located on the housing between the steps. 1285198 A1