Alarm for sensing a reduction of gas supply pressure for respirators

Claim 2

An alarm device for sensing the drop off of pressure between a gas supply container and a respirator, comprising a housing having a control fluid passage therein, a first pressure-operated valve in said control fluid passage having a discharge adapted to be opened in response to the pressure in the line between the gas supply and the respirator to open the conduit for the flow of the control fluid when the pressure in the line drops below a predetermined amount, an alarm conduit having a pressure fluidoperated alarm device, a control fluid passage defining a control zone connected between the discharge of said first pressureoperated valve and said alarm conduit and having a second pressure-operated valve therein, said housing defining a closed zone opposite to said control zone, said second pressure-operated valve being exposed on one side to the pressure of said control zone and on the opposite side by said closed zone and being movable to open and close said alarm conduit, the portion of said valve exposed to said control zone being of a lesser area than the portion on its opposite side exposed to said closed zone, and a throttle passage communicating between said control zone and said closed zone for equalizing the pressure between said zones, the greater area on said valve in said closed zone forcing said valve to a closed position to close off said alarm circuit after the pressures are equalized.

Claim 3

An alarm device accoRding to claim 1, wherein said second pressure control valve comprises a valve body, first and second diaphragms supporting said valve body in said housing between said closed zone and said control zone, one of said diaphragms being exposed to said control pressure and being of a lesser area than the other which is exposed to said closed zone pressure.

Claim 4

An alarm device according to claim 1, including a control spring acting on said second pressure control valve to urge it into an open position.

Claim 5

An alarm device according to claim 1, wherein said first pressure control valve comprises a valve body and a diaphragm supporting said valve body, the diaphragm being exposed on one side to the high pressure line, and a spring acting on said valve body in a direction against the force of said high pressure line.

Claim 6

A gas pressure alarm for respirators for sensing the drop off of pressure between a gas supply container and the respirator, comprising a housing having a first chamber with a gas pressure monitoring inlet connection for connection to the gas supply container, a medium pressure line for an actuating fluid connected into said first chamber, a diaphragm dividing said first chamber into an actuating fluid zone communicating with said medium pressure line and a high pressure gas monitoring zone communicating with said gas pressure monitoring inlet connection, a second chamber in said housing, sealing means dividing said second chamber into a closed zone and a control zone, a first passage between said actuating fluid zone and said control zone having a first valve seat at the connection to said actuating fluid zone, a first valve body carried on said diaphragm and being urged by said diaphragm under the normal operating pressure in said monitoring zone to close upon said first valve seat to close off said first passage, a monitoring force means biasing said first body in a direction to move it off said valve seat when said monitoring pressure is reduced by a predetermined amount; an alarm conduit having a fluid-operated alarm therein connected to said control zone and having an alarm conduit valve seat at the connection thereof to said control zone, said sealing means having a second valve body closeable against said alarm conduit valve seat, and opening spring biasing said second valve body into a normal open position, said sealing means having a throttle passage extending between said control zone and said closed zone for equalizing the pressure between said control zone and said closed zone, said sealing means defining an area on the control zone which is less than the area on said closed zone so as to urge said valve body to close off said alarm conduit after the pressure has been equalized between said control zone and said closed zone by flow through said throttle passage.

Claim 7

A gas pressure alarm for respirators for sensing the drop off of pressure between a gas supply container and the respirator, comprising a housing having a first chamber with a gas pressure monitoring inlet connection for connection to the gas supply container, a medium pressure line for an actuating fluid connected into said first chamber, a diaphragm dividing said first chamber into an actuating fluid zone communicating with said medium pressure line and a high pressure gas monitoring zone communicating with said gas pressure monitoring inlet connection, a second chamber in said housing, sealing means dividing said second chamber into a closed zone and a control zone, a first passage between said actuating fluid zone and said control zone having a first valve seat at the connection to said actuating fluid zone, a first valve body carried on said diaphragm and being urged by said diaphragm under the normal operating pressure in said monitoring zone to close upon said first valve seat to close off said first passage, a monitoring force means biasing said first body in a direction to move it off said valve seat when said monitoring pressure is reduced by a predetermined amount; an alarm conduit having a fluid-operated alarm therein connected to said control zone and having an alarm conduit valve seat at the connection thereof to said control zone, said sealing means having a second valve body closeable against said alarm conduit valve seat, and opening spring biasing said second valve body into a normal open position, said sealing means having a throttle passage extending between said control zone and said closed zone for equalizing the pressure between said control zone and said closed zone, said sealing means defining an area on the control zone which is less than the area on said closed zone so as to urge said valve body to close off said alarm conduit after the pressure has been equalized between said control zone and said closed zone by flow through said throttle passage.