Micro-flow measurement is widely used in many industries. The smaller the flow, the more difficult it is to measure. It is also a challenge for instrument manufacturers. In the selection of flowmeter for measuring small flow, the following points should be paid attention to.

1. Instrument performance refers to the accuracy, repeatability, linearity, range ratio, pressure loss, initial flow, output signal and response time of the instrument. Flow selection timing should carefully analyze and compare the above indicators, and select the instrument that can meet the requirements of measuring medium flow.

2. Economic factors refer to purchase fees, installation fees, maintenance fees, calibration fees and spare parts, which are also affected by the performance, reliability and life of gas flowmeter.

3. Installation conditions refer to gas flow direction, pipeline direction, upstream and downstream straight pipeline length, pipe diameter, space location and pipe fittings, which will affect the accurate operation, maintenance and service life of gas flowmeter.

4. Fluid characteristics mainly refer to the pressure, temperature, density, viscosity and compressibility of gas. Since the volume of gas varies with temperature and pressure, whether compensation should be considered.

5. Accuracy grade and function select instrument precision grade according to measurement requirement and use occasion, so as to achieve economic benefit.