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 (Glycerine/ Silicone Oil) 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 adjustments, the Bezel & Glass has to be re-assembled and again the Case has to be filled with Liquid.
Pressure Gauges with Zero Adjustment
In order to overcome this difficulty, Manufacturers have developed a unique design of External Zero Adjustment.
Image courtesy: Ashcroft
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. This arrangement is highly recommended from the maintenance view, especially for Liquid filled Gauges.
- Pressure Gauge Datasheets
- Remote Seal Transmitter for Vacuum
- Pressure Measurement Compensation
- Installation of Pressure Gauges
- Vacuum Gauges Principle