Vacuum pump lubricants

Patent metadata

Field	Value
Publication number	US-10662955-B2
Application number	US-201615566521-A
Country	US
Kind code	B2
Filing date	Mar 11, 2016
Priority date	Apr 14, 2015
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

A vacuum pump may include a rotor and a stator, wherein the rotor is supported by metal bearings (such as steel bearings) to allow relative rotation of the rotor with respect to the stator. A liquid PFPE lubricant compound is provided to lubricate the bearings, wherein the lubricant further comprises a solid lubricant that is in suspension in the liquid lubricant. The solid lubricant can comprise any of graphite, graphene and molybdenum disulphide. In other words, the inventive concept encompasses a lubricated bearing arranged to support a rotating shaft in a body under sub-atmospheric conditions, wherein a lubricant used to lubricate the bearing comprises liquid PFPE lubricant having a low vapour pressure, and a solid lubricant that is held in suspension in the liquid lubricant. The solid lubricant may comprise any of graphite, graphene and molybdenum disulphide.

First claim

The invention claimed is:

1. A vacuum pump comprising:
a rotor mounted inside a stator;
at least one roller bearing arrangement disposed on a shaft of the rotor to allow rotation of the rotor with respect to the stator; and
a lubrication supply arranged to supply a lubricant compound to the roller bearing, wherein the lubricant compound comprises a liquid and a solid component, the liquid component comprising a PFPE lubricant, the solid component comprising graphene held in suspension within the liquid component, wherein the graphene is functionalized with a fluorinated organothiol for improved dispersion in the liquid component.

2. The vacuum pump according to claim 1 , wherein the roller bearing arrangement comprises metal ball bearings disposed between inner and outer races, said races being made from metal.

3. The vacuum pump according to claim 1 , wherein the liquid component comprises a PFPE compound having a low vapour pressure suitable for use at sub-atmospheric pressures without causing contamination of a chamber that the vacuum pump is evacuating.

4. The vacuum pump according to claim 1 , wherein the solid component comprises between 0.001% to 10% of total volume of the lubricant.

5. The vacuum pump according to claim 4 , wherein the solid component comprises between 0.01% to 1% of total volume of the lubricant.

6. A vacuum pump lubricant comprising:
a solid component; and
a liquid component, wherein the solid component is held in a suspension in the liquid component, and wherein the liquid component is a PFPE lubricant and the solid component comprises graphene, wherein the graphene is functionalized with a fluorinated organothiol for improved dispersion in the liquid component.

7. The vacuum pump of claim 1 , wherein the solid component further comprises at least one of graphite or molybdenum sulphide.

8. The vacuum pump lubricant of claim 6 , wherein the solid component further comprises at least one of graphite or molybdenum sulphide.

Assignees

• Edwards Ltd

Inventors

• Shaw Christopher John

Classifications

• C10M2201/066

  Molybdenum sulfide · CPC title

• F04D19/04 Primary

  specially adapted to the production of a high vacuum, e.g. molecular pumps · CPC title

• F04D29/063 Primary

  specially adapted for elastic fluid pumps · CPC title

• C10M2213/0606

  used as base material · CPC title

• C10N2050/015

  Dispersions of solid lubricants · CPC title