It can be considered from five aspects, these five aspects are flow meter performance, fluid characteristics, installation conditions, environmental conditions and economic factors. The detailed factors of the five aspects are as follows:
1. Instrument performance: accuracy, repeatability, linearity, range, flow range, signal output characteristics, response time, pressure loss, etc.;
2. Fluid characteristics: temperature, pressure, density, viscosity, chemical corrosion, abrasiveness, fouling, miscibility, phase change, electrical conductivity, speed of sound, thermal conductivity, specific heat capacity, isentropic index;
3. Installation conditions: pipeline arrangement direction, flow direction, length of straight pipe section on the upstream and downstream sides of the test piece, pipe diameter, maintenance space, power supply, grounding, auxiliary equipment (filter, getter), installation, etc.;
4. Environmental conditions: ambient temperature, humidity, electromagnetic interference, safety, explosion-proof, pipeline vibration, etc.;
5. Economic factors: instrument purchase, installation, operation, calibration, maintenance, instrument service life, spare parts, etc.