Pressure regulator for breathing apparatus

Claim 1

A pressure regulator for a breathing apparatus comprising: a hollow casing, a semi-rigid, deformable membrane mounted in said casing and separating the casing into first and second compartments; said casing having openings formed therein providing communication between said first compartment and the exterior of the casing; and a mouthpiece and a low pressure air inlet conduit connected to said second compartment; a regulating valve located in said second compartment for controlling the delivery of air from said inlet conduit to said second compartment, said valve including a valve seat; a valve head, a sealing pellet mounted in said valve head, a control rod having a first end secured to said valve head and a second free end, opposite said first end, and return spring means for maintaining said pellet sealingly applied against said valve seat; a lever located in said second compartment having one end operatively connected to the free end of said control rod and an opposite end operatively connected to said semi-rigid membrane for automatically displacing said control rod and said valve head away from said valve seat when the pressure in said first compartment is greater than the pressure in said second compartment, said regulating valve including a cylindrical chamber mounted in said second compartment in communication with said inlet conduit, said valve head and control rod slidably mounted in said cylindrical chamber, a nozzle slidably mounted in said cylindrical chamber for sliding movement coaxial with said valve head, said nozzle having axially opposed front and rear ends with said front end facing said valve head and defining said valve seat and said rear end including a hollow piston having two opposite front and rear faces located within said cylindrical chamber; said cylindrical chamber having two opposite ends including a rear end connected to said inlet conduit for low pressure air and a front end forming an abutment for the front face of the piston, whereby when said inlet conduit is supplied with compressed air the rear face of said piston is subjected to the pressure of the air in said chamber and the piston is maintained in a fixed position with its front face in abutment against the front end of said cylindrical chamber by said pressure, and when the inlet conduit is not connected to compressed air the rear face of the piston is no longer subjected to pressure and the piston retracts inside said chamber and draws back the nozzle and valve seat.