Pressure gauge for fire extinguisher - has differently coloured plungers slidably telescoped in one another and projecting into transparent head member

摘要

The pressure gauge comprises one or more plungers possibly cup-shaped and of different colours which are telescopically engaged in one another and axially movable within a transparent head member. The plungers are made responsive to the pressure in the fire-extinguisher bottle or any other source of pressure by means of a membrane of a plunger provided with a toroidal gasket of "O-ring" type. The plungers are arranged so as to serve as indicator members in that they can slide in a bore which is formed in a transparent member which is mounted in a suitable positin and shaped so that its bottom surface behaves as a reflecting surface that transmits to an observer the image of a portion of the plunger and therefore its colour.