Differential Pressure Gauges

Generally Pressure Gauges and Differential Pressure Gauges are provided with Micrometer type Pointer, by which zero can be adjusted after opening the bezel & glass.

However for gauges with Liquid filled Case, this arrangement is practically not suitable, since the filling liquid has to be drained before opening the bezel & glass.

After doing the zero adjustment, the Bezel & Glass has to be re-assembled and again the case has to be filled with Liquid. In order to overcome this difficulty, general instruments Consortium has developed a unqiue design if external zero adjustment. 

By this arrangement, zero can be adjusted without draining the Glycerine, without opening the Bezel, without removing the glass & without touching the pointer, just by rotating a knob provided outside the gauge.