Vacuum pump
US6779969B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2002 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Jan 20, 2023 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04D19/046
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A thread-groove pump mechanism portion PB employs a turn-back structure including a rotor formed of a multiple cylinder having an inner cylindrical rotor and an outer cylindrical rotor and a stator formed of a multiple cylinder having an inner cylindrical stator and on outer cylindrical stator. Gaps g1 and g3 defined by the outer walls of the rotor and the stator walls, and a gap g2 defined by the inner cylinder wall of the rotor and the stator wall during the rest of the pump are formed such that they increase with the distance from the rotor shaft center and g1>g2 and g1>g3 are satisfied. Thus, even if displacement occurs by the centrifugal force and thermal expansion during the operation of pump, predetermined gaps can be provided therebetween.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.