Protective breathing apparatus and valve therefor
US3990439A · kind A · utility
36Cited by
7References
7Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1974 |
| Grant date | Nov 9, 1976 |
| Priority date | — |
| Expiry date | Dec 5, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/789
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A respirator or gas mask has a check valve having a seat with a raised border. A soft rubber valve is located on the seat and held thereto by a valve retainer. When the valve is not under any pressure, the valve is sealed solely by contact between the rim of the valve and the raised portion of the seat. When back-pressure is placed on the valve, it seats on the entire valve seat area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.