Non-bursting ferrofluid seal
US6543782B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 2001 |
| Grant date | Apr 8, 2003 |
| Priority date | — |
| Expiry date | Jun 9, 2021 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16J15/43
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
Magnetic fluid seals containing housings, magnets, pole pieces, gaps, magnetic fluids, shafts and bearings of standard type are modified to permit operation at two levels of magnetic intensity in the gaps. During exposure to the operating pressure difference that a seal is designed to withhold, the magnetic field intensity in the gaps is maintained at a relatively low intensity. Subsequently, the magnetic field intensity in the gaps is increased to yield burst-free operation. Various embodiments for adjusting the magnetic field intensity are disclosed. These include: magnetic fluid seal with a variable magnet to pole-block spacing; seal with hollow-shaft flux intensifier; seal with surrounding flux diverter; and seal with an internal magnetic coil that furnishes opposing magnetomotive force.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.