Pneumatic pressure regulator redundant valving

Claim 1

A pneumatic pressure regulator having inlet and outlet ports therein comprising, in combination, a body portion having a cylindrical bore section with the outlet port in the lower part thereof, a piston slidably disposed in said cylindrical bore section above the outlet port, biasing means for urging said piston downward, a piston stem attached to the lower face of said piston and extending downwardly through a close fitting bore; and primary valve means disposed in a first axial bore in the lower section of said body portion in communication with the inlet port of said pneumatic regulator, secondary valve means disposed in a second axial bore immediately above and in communication with said first axial bore, said primary valve means and first axial bore being larger in diameter than said secondary valve means and second axial bore, biasing means for urging said primary and secondary valve means upward against their respective seats, said piston stem maintaining contact with the surface of said secondary valve means, and a spacer pin slidably positioned between and within said primary and secondary valve means for transmitting compressive forces from said piston stem through said secondary valve means to said primary valve means and for permitting independent vertical movement of said secondary valve means in response to the regulating movement of said piston stem after failure of said primary valve means.