1. to make clear the use of the valve in the equipment or device, to determine the valve can work under what conditions, what is the applicable medium, working pressure and temperature are how much;
2. understand the nominal size and connection mode of the pipe connected with the valve: flange, thread, welding, etc.;
3. determine the way to operate the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electro-hydraulic linkage;
4. according to the pipeline transmission medium, working pressure, working temperature to determine the selected valve shell and inner parts of the material: cast steel, carbon steel, stainless steel, alloy steel, stainless acid steel, copper alloy;
5. select the type of valve, determine the valve type, parameters and the selected valve geometric parameters, such as: structure length, flange connection form and size, open and close after the height direction of the valve size, bolt hole size and number of connection, the size of the entire valve shape;
6. when choosing baotou valves, sometimes not only to undertake choosing according to more than a few, but also to choosing a valve on the basis of follow: selected valve ;
7. to clear the way of use, the working conditions of use and operation control, the valve specifications and categories, should accord with the requirement of pipe design documents, working pressure is greater than or equal to the pipe work pressure;
8. understand the nature of the working medium: working pressure, working temperature, corrosion performance, whether it contains solid particles, whether the medium is toxic, whether it is flammable, explosive medium, viscosity of the medium, etc;
9. understand the requirements of the valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, seal grade, etc;
10. clear installation size and external size requirements: nominal size, pipe connection and connection size, external size or weight limit, etc;
11. Additional requirements for the reliability, service life and explosion-proof performance of electric devices of the valve products.
