Pressure monitoring device for self-contained breathing apparatus.

摘要

There is disclosed a pressure monitoring device for self-contained breathing apparatus including visual indicators disposed in the field of view from the headpiece to monitor when predetermined pressure levels are reached in the tank which supplies gas to that headpiece. The predetermined pressure levels are referenced to the residual tank pressure at which the required breathing gas flow is not sustained and visual alarm provisions anticipate those predetermined pressure levels which are critical, in some embodiments of the invention. A cost effective transducer of reduced pressure range senses the tank pressure and noise is eliminated from the transducer signal by common mode rejection in still other embodiments. <IMAGE>