1. To know the application of
valves in device and equipment, as well as working condition, practical medium, working pressure and working temperature.
2. To confirm the nominal diameter and connectiong method: flanged, threaded, welded, ect.
3. Make out the
valves' operating method: manual, electric, electromagnetic, pneumatic or hydraulic, electrohydraulic and so on.
4. According to the medium transported by pipe lines, working pressure and working temperature, to confirm the shell and internals of selected
valves: cast iron, carbon steel, stainless steel, aloy steel, stainless acid-resistant steel, gray cast iron, malleable cast iron, ductile cast iron, copper alloy, etc.
5. Choose the
valve types: closed-circuit valves, regulating valves, safety valves, etc.
6. Check the
valve pattern: gate valve, globe valve, ball valve, butterfly valve, throttle valve, safety valve, pressure reducing valve, steam trap, etc.
7. Check the
valve parameters: as for active valves, it is necessary to determine the allowable flow resistance, discharge capacity, back pressure, ect., and then determine the nominal diameter of pipeline and the diameter of valve seat hole.
8. Check the geometrical parameter: structure length, flange connection and its size, valve height and size after opening and closing, size and number of bolt holes for connection, and overall dimensions of all valves, etc.
9. Using the existing materials, such as
valve product catalogue, valve product samples to select the appropriate valve products.