Standard dual scale metric ranges have a dominant metric inner scale the outer scale is specified in psi.
Pressure gauge range selection standard.
Pressure gauge scale ranges scale spacing and scale numbering per en 837 wika data sheet in 00 02 wika data sheet in 00 02 12 2008 page 1 of 4 in general the design of the scale depends on scale range nominal size ns diameter of case and accuracy class of a pressure gauge.
To select the right pressure gauge for your application the following factors should be considered.
European norm en 837 1 and en 837 3 provide.
Liquid filling of the case ensures precise readability for the pressure gauge even with high dynamic pressure loads and vibrations.
Duragauge gauges are made in accordance with asme b40 1 enti tled gauges pressure indicating dial type elastic element accuracy grade 2a 0 5 of span the accuracy of a retard range gauge applies.
If a gauge is not selected considering these criteria it may result in fatigue of the bourdon tube.
Asme b40 100 recommends that normal operating pressure be confined to 25 75 of the scale.
The maximum operating pressure should not exceed 75 of the full scale range.
When it comes to the highest accuracy within wika s broad selection you will also find precision pressure gauges measuring with accuracies of 0 1 0 25 or 0 6 of the full scale value.
Some examples are shown.
For a mechanical pressure gauge accuracy is defined either as a percentage of the full scale range or a percent of the span.
Conclusion to properly select a pressure gauge consider the gauge process range environment accuracy dial.