Automatic Switching Device for a Breathing Apparatus with an Alarm-Relief Function and Automatic Reset

摘要

Apparatus and associated methods relate to an automatic fluid alarm that provides an fluid-communication path between a secondary fluid source and a whistle port when a primary fluid source experiences a reduction in pressure, the automatic fluid alarm being user resettable by disconnecting the primary fluid source or otherwise reducing the primary source pressure and activating a reset member, thereby interrupting the fluid-communication path. In some examples, a piston member may provide a movable seal for providing the fluid-communication path and its interruption. An exemplary piston member may be slidably reset in a non-interrupting mode by an adequate primary fluid pressure, and slidably set in an interrupting mode by a user activation. The interrupting mode may silence the whistle which may facilitate user communication during what may be a stressful primary fluid source failure event. Some exemplary automatic fluid alarms may conserve secondary fluid when the whistle is silenced.