The history of water measurement is very long. Orifice plates were used to measure the drinking water volume of residents in the Caesar era in ancient Rome. The famous Dujiangyan Irrigation Project Water Conservancy Project in China used the water level at Baopingkou to observe the water volume, which is a typical case of water measurement. A large number of water flow meters are required in modern urban water supply, heating, fire protection, sewage treatment, and industrial production; In different occasions, due to different functions and personal preferences, there are different types of flow meters to choose from. Generally, the following principles can be followed to select the appropriate type of flow meter.

1. Electromagnetic flowmeter, ultrasonic flowmeter, and turbine flowmeter can be selected for measuring tap water;

2. Select electromagnetic flowmeter for measuring conductive media such as sewage and beer;

3. Heating and heating air conditioning generally use electromagnetic flow meters and ultrasonic flow meters;

4. Electromagnetic flowmeter, ultrasonic flowmeter, metal rotor flowmeter, and vortex flowmeter are selected for fire protection;

5. Vortex flowmeter is selected for measuring desalinated water, softened water, purified water, and high-temperature water;

6. Optimal electromagnetic flowmeter for measuring acidic and alkaline solutions, electrolytes, etc;

7. Use a magneto electric vortex flowmeter for measuring oil-water mixtures;

8. Metal rotor flow meters and glass rotor flow meters are generally used for process measurement;

9. Elliptical gear flowmeter, waist wheel flowmeter, and turbine flowmeter are selected for measuring diesel, gasoline, and edible oil;

10. Standard orifice flowmeter is selected for measuring thermal oil.