Breathing apparatus

Aug. 17, 1965

D. O. A. JOHANNISSON

BREATHING APPARATUS

Filed Nov. 5, 1962

3,200,818

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FIG. 3

FIG. 2

INVENTOR

DAG OLOF ALFRED JOHANNISSON

BY

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ATTORNEYS

United States Patent Office _Palented a^®’^ piston 13 which is movable between an upper and a lower position. In the upper position the valve housing 1 is connected via the proximate portion of the exhalation tube 2 to the surrounding atmosphere and the portion of the exhalation tube next to the supply tube 3 is blocked. In the lower position, the connection shown in FIG. 1 is established.

The operation is as follows:

On inhalation, a subpressure is set up in the housing 1 and the valve disc 12 is lifted off its lower valve seat, whereby gas is sucked in from the breathing bag 6.

On exhalation, the disc 12 is urged by the breathing pressure downwardly to the lower valve seat and the upper valve seat is disengaged, making exhalation possible through the tube 2 and the non-return valve 7 to the gas purifier 4 and on to the breathing bag 6.

The gas supplied from the supply tube 3 passes through the non-return valve 7 to the breathing bag 6. If no counterpressure is present under the non-return valve 7, this valve opens, owing to its larger surface, more easily than the overflow valve 8.

The spring 11 may be adjustable through an adjustment of the disc 9. For example the disc 9 may be threaded onto the stem 10.

If artificial respiration is to be performed, the breathing bag 6 is compressed so as to make air be supplied to the breathing organs. The non-return valve is then closed and the valve disc 12 is removed from the lower valve seat in the same way as during inhalation.

The breathing may be arrested by the exertion of a certain pressure on the breathing bag 6. The supplied gas can then always flow off through the overflow valve 8, owing to the fact that this valve as well as the supply tube is placed to the rear of the non-return valve with regard to the direction of the air flow.

The common guiding of the non-return valve 7 and the overflow valve 8 with the common spring 11 for biasing both valves has the advantage that the non-return valve 7 in its opened position increases the spring bias on the overflow valve 8, thereby counteracting opening of the latter valve, which would otherwise be possible upon very rapid exhalation.

The modified embodiment according to FIG. 3 operates according to the same principle as just described. However, exhalation now takes place direct to the surrounding atmosphere. The gas purifier 4 may obviously be dispensed with in this case.