Detailed knowledge of various valves
Valve is a control component in a fluid delivery system that functions to cut off, regulate, divert, prevent backflow, stabilize, split or overflow. According to different classification standards, the types of valves are various, and each valve has its own unique place.
Classified by function and purpose
Shut-off valve: A shut-off valve, also known as a closed-circuit valve, is used to switch on or off the medium in the pipeline. Cut-off valves include gate valves, globe valves, plug valves, ball valves, butterfly valves, and diaphragms.
Check valve: Check valve, also known as check valve or check valve, is used to prevent backflow of media in the pipeline. The bottom valve of the water pump suction is also a check valve.
Safety valve: The function of the safety valve is to prevent the pressure of the medium in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.
Regulating valve: The regulating valve includes a regulating valve, a throttle valve and a pressure reducing valve, and its function is to adjust parameters such as pressure and flow of the medium.
Diverter: The diverter valve includes various distribution valves and traps, etc., which function to distribute, separate or mix the medium in the pipeline.
2. Classified by nominal pressure
Vacuum valve: refers to a valve whose working pressure is lower than the standard atmospheric pressure.
Low pressure valve: refers to the valve with nominal pressure PN ≤1.6Mpa.
Medium pressure valve: refers to the valve with nominal pressure PN of 2.5, 4.0, 6.4Mpa.
High pressure valve: refers to the valve whose working pressure PN is 10~80Mpa.
Ultra high pressure valve: refers to the valve with nominal pressure PN≥100Mpa.
3. Classified by working temperature
Ultra-low temperature valve: for valves with media operating temperature t < -100 °C.
Cryogenic valve: for valves with medium working temperature -100 °C ≤ t ≤ -40 °C.
Normal temperature valve: for valves with medium working temperature -40 °C ≤ t ≤ 120 °C.
Medium temperature valve: for medium working temperature 120 ° C
High temperature valve: for valves with medium working temperature t>450°C.
4. Classified by driving method
An automatic valve is a valve that does not require external force to drive, but relies on the energy of the medium itself to actuate the valve. Such as safety valves, pressure reducing valves, traps, check valves, automatic regulating valves, etc.
Power-driven valves: Power-driven valves can be driven by a variety of power sources.
Electric valve: With an electric drive valve.
Pneumatic valve: A valve driven by compressed air.
Hydraulic valve: A valve that is driven by a liquid pressure such as oil.
In addition, there are combinations of the above several driving methods, such as gas-electric valves.
Manual valve: The manual valve uses manpower to manipulate the valve action by means of the hand wheel, handle, lever and sprocket. When the valve opening and closing torque is large, the wheel or worm gear reducer can be arranged between the hand wheel and the valve stem. If necessary, you can also use the universal joint and the drive shaft for remote operation.
5. Classified by nominal diameter
Small diameter valve: a valve with a nominal diameter of DN ≤ 40mm.
Medium diameter valve: a valve with a nominal diameter of 50 to 300 mm.
Large-diameter valve: The valve with a nominal valve DN of 350-1200mm.
Extra large diameter valve: valve with nominal diameter DN ≥ 1400mm.
6. Classification by structural characteristics
Threshold valve: the opening and closing member (valve) is driven by the valve stem to move up and down along the center line of the valve seat;
Plug valve: the opening and closing member (gate valve) is driven by the valve stem to move up and down along the center line perpendicular to the valve seat;
Plug valve: the opening and closing member (cone plug or ball) rotates around its own center line;
Swing valve: the opening and closing member (valve) rotates around the shaft outside the seat;
Butterfly valve: the opening and closing member (disc) rotates around a fixed shaft in the valve seat;
Spool valve: The opening and closing member slides in a direction perpendicular to the passage.
7. Sort by connection method
Threaded valve: The body has internal or external threads and is threaded into the pipe.
Flange connection valve: The valve body is flanged and connected to the pipe flange.
Welded connection valve: The valve body has a welding groove and is welded to the pipe.
Clamp connection valve: The valve body has a jaw and is connected to the pipe clamp.
The ferrule is connected to the valve: it is connected with the pipe with a ferrule.
Connecting the valve to the clamp: A connection form in which the valve and the two pipes are directly clamped together by bolts.
8. Classified by body material
Metal material valve: The valve body and other parts are made of metal material. Such as cast iron valves, carbon steel valves, alloy steel valves, copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves.
Non-metallic valve: The valve body and other parts are made of non-metallic materials. Such as plastic valves, ceramic valves, 搪 valves, glass steel valves, etc.
Metal valve body lining valve: The shape of the valve body is metal. The main surfaces in contact with the medium are lining, such as rubber-lined valve, plastic-lined valve, and ceramic-lined valve.