US3776422A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compressed gas breathing apparatus
Assignee: MSA Safety Inc
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Filing: 1972-10-25
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Granted: 1973-12-04
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Expires: 1992-10-25
Abstract
Abstract A pressure reducer is connected between a source of high pressure breathing gas and the inlet of a normally closed pneumatically operated control valve, the outlet of which is connected with a pressure reducing demand valve leading to a facepiece. A tube also connects the breathing gas source with another part of the control valve for holding the latter open as long as the breathing gas pressure remains above a predetermined value, whereby the control valve connects the pressure reducer with the demand valve. A normally closed pneumatically operated alarm valve also connects the pressure reducer with the demand valve, but is formed and constructed to be snapped open by the pressure drop across it only when the demand valve is opened while the control valve is closed due to reduction in the gas pressure below said predetermined value. The pulse of gas created every time the alarm valve opens signals the user that the control valve has closed.
Inventors
- 👤 L Wise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:14
CPC Classifications
A; A61; A61M; A61M16/00; A61M16/0051
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
177 words
Compressed gas breathing apparatus comprising a conduit with an inlet for connection to a source of breathing gas under high pressure, a normally closed pneumatically operated control valve with an outlet, a normally closed pneumatically operated alarm valve with an outlet, a pressure-reducing demand valve having an inlet connected with said valve outlets and having an outlet for connection to a facepiece, gas-conducting means connecting the outlet of said conduit with the inlets of said valves, said control valve containing pneumatic pressure actuated means for holding it open as long as said gas pressure remains above a predetermined value to thereby connect said conduit with the demand valve, the alarm valve being formed and constructed to be opened abruptly by the pressure drop across it every time the demand valve is opened while said control valve is close due to reduction in said gas pressure below said pre-determined value, whereby to create a pulse of gas at the outlet of the demand valve that will signal the user of the apparatus that the control valve has closed.
Claim 2
Dependent Claim
177 words
Compressed gas breathing apparatus comprising a conduit with an inlet for connection to a source of breathing gas under high pressure, a normally closed pneumatically operated control valve with an outlet, a normally closed pneumatically operated alarm valve with an outlet, a pressure-reducing demand valve having an inlet connected with said valve outlets and having an outlet for connection to a facepiece, gas-conducting means connecting the outlet of said conduit with the inlets of said valves, said control valve containing pneumatic pressure actuated means for holding it open as long as said gas pressure remains above a predetermined value to thereby connect said conduit with the demand valve, the alarm valve being formed and constructed to be opened abruptly by the pressure drop across it every time the demand valve is opened while said control valve is close due to reduction in said gas pressure below said pre-determined value, whereby to create a pulse of gas at the outlet of the demand valve that will signal the user of the apparatus that the control valve has closed.
Claim 3
Dependent Claim
17 words
Compressed gas breathing apparatus according to claim 1, in which said gas-conducting means is a pressure reducer.
Claim 4
Dependent Claim
35 words
Compressed gas breathing apparatus according to claim 2, including a tube connecting said conduit with said pressure actuated means in the control valve for applying said gas pressure thereto to hold the control valve open.
Claim 5
Dependent Claim
82 words
Compressed gas breathing apparatus according to claim 3, in which said control valve includes a valve port encircled by a seat between the inlet and outlet of that valve, a closure member, and a spring normally holding said closure member against said seat, and said pressure actuated means includes a piston operatively connected with said closure member for moving it away from said seat against the resistance of said spring, the control valve having a passage connecting said tube with said piston.
Claim 6
Dependent Claim
28 words
Compressed gas breathing apparatus according to claim 4, including means for adjusting the pressure exerted by said spring, whereby to control said predetermined value of said gas pressure.
Claim 7
Dependent Claim
25 words
Compressed gas breathing apparatus according to claim 4, including a stem extending through said valve port and rigidly connected to said piston and closure member.
Claim 8
Dependent Claim
49 words
Compressed gas breathing apparatus according to claim 4, including a stem extending through said valve port and rigidly connected to said piston and closure member, and a collar threaded on said stem, said spring being a coil spring encircling said stem and compressed between said collar and valve port.
Claim 9
Dependent Claim
93 words
Compressed gas breathing apparatus according to claim 1, in which said alarm valve includes a valve seat, a diaphragm between the seat and the valve outlet, a normaLly closed chamber having said diaphragm as one wall whereby a predetermined gas pressure in the chamber will hold the diaphragm against said seat to maintain the valve closed, a normally closed check valve for said chamber, and means actuated by said pressure drop for opening said check valve so that the gas pressure at the valve inlet will force the diaphragm away from its seat.
Claim 10
Dependent Claim
67 words
Compressed gas breathing apparatus according to claim 8, in which said check valve includes a closure member and movable valve seat normally engaging each other, and said check valve opening means includes means supporting said first-mentioned seat for movement toward the valve outlet when said pressure drop occurs, and means connecting said supporting means with the check valve seat for moving it away from said closure member.
Claim 11
Dependent Claim
59 words
Compressed gas breathing apparatus according to claim 9, in which said supporting means includes an annular disc provided with an axial passage encircled by said first-mentioned seat, and a diaphragm supporting said disc and provided with a central opening aligned with said passage, the alarm valve also including a spring urging said check valve seat toward said closure member.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |