Dry vacuum pump with pressurized bearing and seal

Patent metadata

Field	Value
Publication number	US-10851783-B2
Application number	US-201615771776-A
Country	US
Kind code	B2
Filing date	Oct 31, 2016
Priority date	Nov 3, 2015
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A dry vacuum pump, comprising a pump housing, which forms a plurality of suction chambers, wherein rotor elements are arranged in the suction chambers, in order to convey a pump medium from a high-vacuum-side inlet to an outlet. At least one rotor element is arranged in each suction chamber. The rotor elements are connected to a rotor shaft. The rotor shaft is supported by bearings, wherein a high-vacuum-side bearing is arranged in a cut-out. A sealing device is arranged between the high-vacuum-side bearing and at least one suction chamber adjacent to the high-vacuum-side bearing. The cut-out is connected, by means of a first channel, to a region of the dry vacuum pump in which there is a higher pressure than in at least one suction chamber adjacent to the high-vacuum-side bearing.

First claim

What is claimed is:

1. A dry vacuum pump, comprising:
a pump housing defining a plurality of suction chambers,
rotor elements arranged in the plurality of suction chambers for conveying a pump medium from a high vacuum-side inlet to an outlet, wherein at least one rotor element of the rotor elements is arranged in each of the plurality of suction chambers,
a rotor shaft connected with the rotor elements, and
bearings supporting the rotor shaft, wherein the bearings comprise a high vacuum-side bearing arranged in a recess,
wherein a seal is arranged between the high vacuum-side bearing and one suction chamber of the plurality of suction chambers is adjacent the high vacuum-side bearing, and
wherein a first duct connects the recess with a region of the dry vacuum pump in which a higher pressure prevails than in the one suction chamber adjacent the high vacuum-side bearing.

2. The dry vacuum pump of claim 1 , wherein the high vacuum-side bearing is a grease-lubricated bearing.

3. The dry vacuum pump of claim 1 , wherein oil is present neither in the recess, nor in the seal.

4. The dry vacuum pump of claim 1 , wherein the seal comprises at least one lip seal.

5. The dry vacuum pump of claim 4 , wherein the at least one lip seal is a PTFE lip seal.

6. The dry vacuum pump of claim 1 , wherein the seal comprises at least two lip seals, and an intermediate chamber between the at least two lip seals is connected, via a second duct, with a second region of the dry vacuum pump in which a pressure prevails that is higher than the pressure in the one suction chamber adjacent the high vacuum-side bearing and lower than the pressure in the recess.

7. The dry vacuum pump of claim 6 , wherein two suction chambers are connected by a connecting duct for a fluid communication of the plurality of suction chambers, and that the first duct and/or the second duct are respectively connected with one connecting duct.

8. The dry vacuum pump of claim 6 , wherein the first and/or the second duct are directly connected with a respective suction chamber.

9. The dry vacuum pump of claim 1 , wherein, in the one suction chamber adjacent the high vacuum-side bearing, a pressure less than 0.01 mbar prevails.

10. The dry vacuum pump of claim 1 , wherein a pressure prevailing in the recess is lower than an ambient pressure of other regions of the dry vacuum pump.

11. The dry vacuum pump of claim 1 , wherein a pressure prevailing in the recess is higher than 100 mbar.

12. The dry vacuum pump of claim 11 , wherein two of the plurality of suction chambers are separated by a partition wall and the connecting duct is arranged in the partition wall.

13. The dry vacuum pump of claim 11 , wherein the pressure prevailing in the recess is higher than 400 mbar.

14. The dry vacuum pump of claim 1 , wherein a pressure difference between the one suction chamber adjacent the high vacuum-side bearing and the recess is less than 300 mbar.

15. The dry vacuum pump of claim 14 , wherein the pressure difference between the one suction chamber adjacent the high vacuum-side bearing and the recess is less than 200 mbar.

16. The dry vacuum pump of claim 1 , wherein the first duct has two points of connection with the recess, wherein a respective one of the points of connection is arranged on a respective side of the high vacuum-side bearing, so that no pressure difference exists between the sides of the high vacuum-side bearing.

17. The dry vacuum pump of claim 1 , wherein the high vacuum-side bearing is arranged in an end region of the rotor shaft.

18. The dry vacuum pump of claim 1 , wherein the plurality of suction chambers comprise a first suction chamber, an intermediate suction chamber, and a last suction chamber, wherein the first suction chamber is the one suction chamber arranged immediately adjacent the high vacuum-side bearing, wherein the high vacuum-side inlet is connected with the intermediate suction chamber, wherein the outlet is connected with the last suction chamber, and wherein the pump medium is conveyed from the intermediate suction chamber to the first suction chamber and the pump medium is conveyed from the first suction chamber to the last suction chamber.

19. The dry vacuum pump of claim 1 , further comprising a separation plane of the pump housing extends in the longitudinal direction of the rotor shaft.

Assignees

• Leybold Gmbh

Inventors

• Birch Peter
• Jenkins Robert
• Tunna Clive

Classifications

• F04C18/16

  with helical teeth, e.g. chevron-shaped, screw type {(for non-parallel axes of movement F04C18/48)} · CPC title

• F04C18/126

  with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type · CPC title

• F04C25/02 Primary

  for producing high vacuum (sealing arrangements F04C27/00; silencing F04C29/06) · CPC title

• F04C2240/50

  Bearings · CPC title

• F04C27/009 Primary

  Shaft sealings specially adapted for pumps · CPC title