Generally, vacuum valves have two characteristics: use characteristics and structural characteristics.
Purpose: Used to determine the main purpose and scope of the valve. The characteristics of the valve are: valve category (closed circuit valve, regulating valve, etc.); product type (gate valve, globe valve, butterfly valve, ball valve, etc.); the main components of the valve ( Valve body, valve cover, valve stem, valve disc, sealing surface); valve transmission mode, etc.
Structural characteristics: The structural characteristics include: valve installation, maintenance, maintenance and other methods; the structural characteristics include: the structural length and overall height of the valve ; the connection method with the pipeline (flange connection, threaded connection, clamp connection, external Threaded connection, welding end connection, etc.); the form of the sealing surface (inlay ring, threaded ring, surfacing, spray welding, valve body); the structure of the valve stem (rotating rod, lifting rod, etc.).
Steps for selecting valves.
Clarify the purpose of the valve in the equipment or device, and determine the working conditions of the valve: applicable medium, working pressure, working temperature, etc.
Determine the nominal diameter and connection method of the valve connecting pipeline: flange, thread, welding, etc.
Determine the operation mode of the valve: manual, electric, electromagnetic, pneumatic or hydraulic, electric connection or electric-hydraulic connection, etc.
According to the medium, working pressure and working temperature of the pipeline, determine the shell and internal materials of the selected valve: gray cast iron, malleable cast iron, ductile iron, carbon steel, alloy steel, acid-resistant steel, copper alloy, etc.
Selected valve type: closed circuit valve, regulating valve, etc.
Determine the type of valve: gate valve, globe valve, ball valve, butterfly valve, throttle valve, pressure reducing valve, steam trap, etc.
Seven, the determination of valve parameters: For automatic valves, determine the allowable flow resistance, exhaust volume, back pressure and other parameters as required, and then determine the nominal diameter of the pipeline and the valve seat diameter.
Determine the geometric parameters of the selected valve: structural length, flange connection form and diameter, opening and closing diameter of the valve height, the diameter of the bolt hole and the number of connections, and the external diameter of the entire valve.
Use existing information: valve product catalog, sample parts, etc., to select suitable valve products.