Breathing apparatus with improved regulator particularly for under water use

In a diving breathing apparatus of the two-stage pressure reducing type comprising first stage valve means adapted to be connected to a diving cylinder containing a respiratory gas under high pressure for the reduction of said gas from high pressure to medium pressure, second stage valve means connected to said first stage for the reduction of said gas from medium pressure to breathable pressure, a mouth-piece associated directly to said second stage means, means responsive to each inhalatory lifting suction from the user which exceeds a minimum threshold to open said second stage means to supply respiratory gas to said mouthpiece under breathable pressure, and means to oppose a force to said lifting suction thereby to establish said threshold;

• the improvement in which the said first stage valve means comprises a valve body having an admission duct receiving said gas under high pressure, throttling valve means in said valve body, spring means biasing said valve means to its open position, a chamber in said valve body, and manually operated control means for adjusting the setting of said spring means, whereby said medium pressure may be adjusted by the user in order to adjust said threshold, said throttling valve means comprising a seating member inserted in said valve body and a piston slidably mounted in said chamber and dividing said chamber into first and second compartments, said spring means being positioned in said first compartment, - said piston having fixed thereon a tubular rod having a bore extending through said rod and said piston and provided at one of its extremities with a nozzle adapted to come into sealed abutment with said seating member, said admission duct communicating with said seating member and the outer side of said nozzle when said nozzle is seated on said seating member, said admission duct communicating with said second compartment through said tubular rod when said nozzle is spaced from said seating member, said control means comprising a knob screwed on a threaded plug secured on said valve body, said plug holding said seating member in place between said plug and said valve body, a disc slidably mounted on said rod and located in said first compartment and a plurality of pins slidably mounted in said body between said knob and said disc and in abutment against them, the aforesaid loading spring means being inserted between said piston and said disc whereby the setting of said spring means and consequently the adjustment of said threshold is obtained by screwing and unscrewing said knob.