Improvements in and relating to fans
US3960464A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1975 |
| Grant date | Jun 1, 1976 |
| Priority date | — |
| Expiry date | Mar 25, 1995 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04D25/14
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
This invention relates to a ventilating fan of the kind comprising a housing defining an air passage, and an impeller rotatable from an electric motor or other prime mover within the housing. The invention is concerned with the provision of an improved automatic shutter device which consists of shutter plates which may have their pivot axes tangential to a common circle and movable between a position which closes the air passage and a position which opens said air passage. The shutter device is operated by means responsive to rotation of the impeller shaft for moving the shutter means to the open position when the impeller is rotating and to the closed position when the impeller is not rotating. The shutter operating means may be such that substantially no thrust or load is placed upon the prime mover when it is rotating at a selected operating speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.