US 4,364,384 AGranted

Excess pressure respirator with pressurized breathing gas shutoff

AssigneeDragerwerk Aktiengesellschaft

InventorsErnst Warncke, Adalbert Pasternack

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Abstract

An excess pressure respirator with automatic or manual shutoff valve is disclosed. A breathing bag having at least one movable plate member is utilized to receive and supply breathing air from a user. The plate member is biased to reduce the volume of the bag and apply pressure to the contents of the bag. A pressurized gas source is connected through a connecting line to the bag. A dosing valve is positioned in the connecting line to be opened when the volume of the bag is reduced during an inhalation cycle and then closed so that a dosed quantity of oxygen is supplied to the bag. A shutoff valve is also provided in the connection for shutting flow of breathing gas from the source entirely when the bag falls below a minimum volume which is indicative of a large leak or the removal of a gas mask from the user's face. A manual shutoff may also be provided in the form of a movable block which stops the movement of the biased plate member before it engages the dosing valve to open it.

Claims7

Dependent claims

An excess pressure respirator comprising:

a housing;
a breathing bag mounted to said housing and having at least one movable plate member which moves with change of volume in said bag;
biasing means engaged with said plate member for biasing said plate member in a direction to deflate said bag;
at least one respiration line connected to said bag for inhalation and exhalation cycles from and to said bag;
a pressurized breathing gas source mounted to said housing;
connecting means between said source and said bag for supplying breathing gas to said bag from said source;
a dosing valve in said connecting means for passing breathing gas to said bag in an open position and for blocking such in a closed position, said dosing valve having an actuator and being mounted in said housing such that said actuator is in the path of said movable plate member and said plate member engages the actuator of said dosing valve to open said dosing valve when said bag is deflated during an inhalation cycle;
and a shutoff valve in said connecting means for passing breathing gas therethrough in an open position and for blocking breathing gas therethrough in a closed position, said shutoff valve having an actuator and being mounted in said housing such that said actuator is in the path of said movable plate member and said plate member engages the actuator of said shutoff valve for closing said shutoff valve when said bag is further deflated during a reduction of pressure in said bag below that of an inhalation cycle.

5 more elements

Dependencies are inferred from the claim text.