Definition and Types of Valves
Definition and types of valves
Valve is the control component in the pipeline fluid transportation system, which is used to change the channel section and medium flow direction, and has the functions of diversion, cut-off, regulation, throttling, check, shunt or overflow pressure relief. For the valve of fluid control, the nominal diameter of the valve ranges from very small instrument valve to industrial pipeline valve with diameter of 10m. Under the action of pressure, temperature or other forms of sensing signal, the valve can act according to the predetermined requirements, or simply open or close without depending on the sensing signal. The valve relies on the driving or automatic mechanism to make the lifting, sliding, swinging or rotary movement of the opening and closing parts, so as to change the size of its flow channel area to realize its control function.
What is the types of valves?
Purpose of valve
The first type of automatic valve: depending on the ability of the medium (liquid, gas) itself and the action of the valve. Such as check valve, safety valve, regulating valve, drain valve, pressure reducing valve, etc.
The second type of drive valve: with the help of manual, electric, hydraulic, pneumatic to operate the action of the valve. Such as gate valve, globe valve, throttle valve, butterfly valve, ball valve, plug valve, etc.
By purpose
1. Disconnection: used to connect or cut off pipeline medium, such as globe valve, gate valve, ball valve, butterfly valve, etc.
2. Check valve: used to prevent medium backflow, such as check valve.
3. Regulating: used to regulate the pressure and flow of medium, such as regulating valve and pressure reducing valve.
4. Distribution: used to change the flow direction of medium and distribute medium, such as three-way cock, distribution valve, slide valve, etc.
5. Safety valve: when the medium pressure exceeds the specified value, it is used to discharge excess medium to ensure the safety of pipeline system and equipment, such as safety valve and emergency valve.
6. Other special uses: such as drain valve, vent valve, drain valve, etc.
Classification by use and function
Block valves are mainly used to cut off or connect the medium flow. Including gate valve, globe valve, diaphragm valve, ball valve, plug valve, butterfly valve, plunger valve, ball plug valve, needle type instrument valve, etc. Regulating valves are mainly used to regulate the flow and pressure of medium. Including control valve, throttle valve, pressure reducing valve, etc.
Check valve class - used to prevent media backflow. Including check valves of various structures.
Diverter valves are used to separate, distribute or mix media. Including distribution valve and drain valve of various structures.
Safety valves are used for safety protection when the medium is overpressured. It includes various types of safety valves.
By driving mode
1. Manual: with the help of hand wheel, handle, lever or sprocket, etc., it is driven by manpower. When the transmission torque is large, it is equipped with worm gear, gear and other reduction devices.
2. Electric: driven by motor or other electrical devices.
3. Hydraulic: driven by (water, oil).
4. Pneumatic; driven by compressed air.
