Various types of gas meters are available for gas volume measurement. They are necessary to bill the consumption of the gas. In industry, they are also used for monitoring processes where the exact gas volume is important. Variants of gas meters are rotary piston meters, turbine meters, ultrasonic meters, vortex gas meters, Coriolis meters. They differ in terms of size, area of application and measuring range. Their operating principles are sometimes very different, as these two examples show: Turbine meter
for custody transfer measurements determine the volume flow through a rotating turbine measuring wheel, the number of revolutions of which is proportional to the operating volume that has flowed through. Ultrasonic meter
determine the change of ultrasonic waves with a changed flow velocity of the gas. The gas volume is calculated from this change in the sound frequencies. Electronic volume correctors
are used to determine the gas volume flow in the standard state using the results measured in the operating state. They are necessary because different temperatures and pressures can prevail in the operating state and also changing in the course of the process, but the billing of the gas is based on the energy content of the gas volume in the standard state. Among other things, sulphur and dew point measuring instruments are used in gas measuring systems to determine the gas quality. Sulfur meters:
These instruments are used for measuring sulphur in the trace range because natural or refinery gas often contains sulphur compounds that cause malodour. In addition, they are corrosive and therefore damage the equipment. In some cases, high purity is also required of the gas, for example when used in laboratories and in the agricultural and food industry. High demands are placed on sulphur measuring instruments because of the difficulty of detecting sulphur compounds on different surfaces. Dew point meters:
The dew point of a gas is also decisive for its passage and processing. Dew point measuring instruments determine the dew point and also the relative humidity (stated in percent) or the concentration of humidity (stated in ppm). Other measured values are the ambient temperature and the pressure in the measuring range. Technical applications can be found in gas utilities, in the petrochemical industry, power generation, medicine and pharmaceuticals, biotechnology, environmental technology and the processing of industrial gases.