Mechanical pressure and temperature gauges - Differential pressure gauges - Dimensions, metrology, requirements and testing
|Publication Date:||1 April 2018|
|ICS Code (Measurement of force, weight and pressure):||17.100|
This standard specifies requirements for pressure gauges with Bourdon tubes, diaphragms, bellow springs, pressure springs and capsule springs (with others being permissible) for the measurement of differential pressure also under static pressure. Differential pressure gauges are referred to as "pressure gauges" in the following.
This standard applies to pressure gauges that have a dial with a scale and a pointer.
It applies to nominal sizes from 63 to 160, pressure ranges up to 1 000 bar and for static pressures up to max. 1 000 bar1).
It contains specific test procedures for conducting type and production tests.
The pressure gauges covered here have two separate process medium chambers and two process connections. The connection for higher pressure is marked with the "+" symbol (plus side), and the connection for the lower pressure is marked with the "−" symbol (minus side). The difference between these two pressures is the actual measurand, the differential pressure.
If both pressures are equal, the measurement element remains still (differential pressure = 0). If the pressure on the plus side is greater than the pressure on the minus side, the pointer is in the scale range with positive values.If one of the two pressures changes, the measuring element moves proportionally to the pressure. If pressure gauges with Bourdon tubes are used, it shall be ensured that the differential pressure is not less than 1/6 of the maximum scale value.
The standard also applies to gauges
- with liquid-filled pressure case;
- with pressure transfer fluid;
for oxygen or acetylene. This standard does not apply to pressure gauges for electrical limit signalling.
1) 1 bar = 1 000 mbar = 105 kg/(m ⋅ s2) = 0,1 N/mm2 = 10 N/ cm2 = 105 N/m2 = 105 Pa = 0,1 MPa.