Closed cycle gas mask and breathing equipment for operation under pressure having a severance-operated connection shut-off for the breathing equipment

DETAILED DESCRIPTION The present invention provides a simple switch-off means which allows the user to disconnect himself from the cycle without any major loss of gas by the breathing equipment or to connect with it while the cycle remains ready for use and under pressure.
According to the invention, a gas switch-off device for closing and opening the breathing gas connection to the mask comprises a non-return valve blocking the gas supply in the inhalation direction, which is arranged in the opening of the breathing gas connection device or connection fitting and which is held open by means of a detector device carried either by the mask or the breathing gas connection and opens the valve when the is connected to the breathing gas supply.
The basic advantage of the invention is that the non-return valve is closed instantly upon the separation of the mask from the breathing gas device connection piece due to the pressure prevailing in the respiratory air cycle or with the aid of a biasing spring acting in a closing direction.
Therefore respiratory air cannot escape into the environment.
The breathing equipment remains ready for use, so that an immediate respiratory air supply is guaranteed for a subsequent putting on and connection of the mask.
During the ready-for-use stage the capacity of the device is saved and the user can breathe the surrounding air through the mask or take the mask off, depending on the circumstances.
In the same manner the closure resulting from the de-coupling can be used for a temporary removal of the complete device.
The non-return valve is preferably a disc valve whose flexible disk is folded or moved in the direction opposite its closing direction by means of a fork-shaped detector element in the mask connection.
When the mask is taken off, the disc pops against the valve seat due to its intrinsic spring action and is pressed against it by the pressure prevailing in the respiratory air cycle.
When the mask is connected, the forked detector element pushes against the disc in the opening direction of the non-return valve and folds the disc along a diameter as the folding line with its halves toward the back into the inner chamber of the respiratory air line