Valves generally have two characteristics: service characteristics and structural characteristics.
1 Usage Characteristics
It determines the main performance and range of use of the valve, including:
Valve type (closed valve, regulating valve, safety valve, etc.);
Product type (gate valve, globe valve, butterfly valve, ball valve, etc.);
Main parts of the valve (valve body, valve cover, stem, valve plate, sealing surface);
Valve transmission mode, etc.
2 Structural Characteristics
It determines some structural characteristics of the valve, installation, repair, maintenance and other methods, including:
The structural length and overall height of the valve and the connection form with the pipe (flange connection, thread connection, clamp connection, external thread connection, welding end connection, etc.);
Sealing surface form (insert ring, thread ring, surfacing welding, spray welding, valve body);
Valve stem structure form (rotary rod, lifting rod), etc.
Selection step
(1) Clear the purpose of the valve in the equipment or device, determine the working conditions of the valve: applicable media, working pressure, working temperature, etc.
(2) Determine the nominal diameter and connection mode of the pipeline connected with the valve: flange, thread, welding, etc.
(3) Determine the operation mode of the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electrical linkage or electro-hydraulic linkage, etc.
(4) The shell and internal materials of the selected valve should be determined according to the medium, working pressure and working temperature of the pipeline: gray cast iron, malleable cast iron, ductile cast iron, carbon steel, alloy steel, stainless steel acid resistant steel, copper alloy, etc.
(5) Select the type of valve: closed valve, regulating valve, safety valve, etc.
(6) Determine the valve types: gate v