First stage pressure regulator for emergency breathing apparatus

摘要

A self-registering piston for a pressure regulator (22) that minimizes variability of the target regulated pressure. The pressure regulator valve (22) includes a valve body (50) having a valve seat (56) interposed between an inlet port (54) supplying unregulated pressure and an outlet port. A piston (60) having a piston seat (62) at a first end and a counter-force surface (64) on the second end is positioned to translate axially from an engaged position when a piston seat is engaged with a valve seat and a disengaged position. A biasing mechanism (74) is provided to bias the piston toward the disengaged position. The pressure regulator (22) includes a passageway (86) extending generally from proximate the piston seat (62) to the counter-force surface (64) to couple the counter-force surface with the regulated pressure. The regulated pressure acts on the counter-force surface (64) in opposition to the combination of the unregulated pressure acting on the piston seat (62), the deformation force necessary to deform the piston seat and achieve an air-tight seal, and the biasing mechanism (74) acting on the piston (60). A retaining mechanism is provided for releasably retaining the piston seat (62) to the valve seat (56). A guide mechanism (92) is provided for maintaining a fixed rotational orientation of the piston seat with respect to the valve seat so that a substantially identical rotational orientation is achieved when the piston is removed and reinserted into the valve body (50).