FIRST STAGE PRESSURE REGULATOR FOR EMERGENCY BREATHING APPARATUS

摘要

A self-registering piston for an pressure regulator that minimizes variability of the target regulated pressure. The pressure regulator valve includes a valve body having a valve seat interposed between an inlet port supplying unregulated pressure and an outlet port. A piston having a piston seat at a first end and a counter-force surface 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 is provided to bias the piston toward the disengaged position. The pressure regulator includes a passageway extending generally from proximate the piston seat to the counter-force surface to couple the counter-force surface with the regulated pressure. The regulated pressure acts on the counter-force surface in opposition to the combination of the unregulated pressure acting on the piston seat, the deformation force necessary to deform the piston seat and achieve an air-tight seal, and the biasing mechanism acting on the piston. A retaining mechanism is provided for releasably retaining the piston seat to the valve seat. A guide mechanism 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.