Which flowmeters need temperature pressure compensation, and why?
When measuring superheated steam, temperature and pressure need to be compensated simultaneously. Steam is usually settled by mass flow. Because of any change in temperature or pressure, the density of the steam changes and the mass flow changes as well.
When measuring liquid, the pressure compensation is not needed. Under 5MPa, the temperature effect is usually considered, and the temperature compensation is needed for the accurate measurement. General measurements can be done without any compensation; measuring some hydrocarbons (such as crude oil) generally requires temperature, pressure, and compensation.
When measuring saturated steam, one temperature compensation or single pressure compensation is needed. The density of saturated steam has a constant correspondence with temperature or pressure (saturated vapor density meter), and any one of them can determine the density of saturated steam.
When measuring gas, it needs temperature and pressure to compensate at the same time. Gas is usually settled in standard condition and volume. Because the volume, flow, temperature, or pressure of a gas change, the flow will change.
