Protective breathing device having a filtering apparatus and additional oxygen supply for emergency use
US4019507A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1975 |
| Grant date | Apr 26, 1977 |
| Priority date | — |
| Expiry date | Sep 24, 1995 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA62B7/08
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A protective breathing device comprises a housing having a filter therein and with an inlet air passage through the filter and through an internal passage in the housing to a breathing tube having a mouthpiece which is adapted to be fitted to the wearer. The breathing tube includes an exhaling valve for expelling air which is exhaled through the breathing tube. The housing carries an oxygen cartridge which is fired or opened by a firing pin which penetrates the cartridge in order to supply oxygen into the housing passage for flow through the breathing tube when this is necessary. In addition, the housing has an annular chamber surrounding the inhalation duct carrying an economy bag through which portions of the exhaled air may be recirculated for flow back into the breathing tube on a successive respiration in order to maintain the oxygen content within acceptable limits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.