Valve Classification And Selection Principles
Valve is the control part of the fluid delivery system, with cut-off, regulation, diversion, counter flow prevention, pressure regulation, shunt or overflow pressure relief and other functions. Classification by function and application is as below:
1.Truncation valve: truncation valve is also known as closed-circuit valve, its role is to connect or truncate the pipeline medium. Which includes gate valves, globe valves, plug valves, ball valves, butterfly valves and diaphragm valves, etc.
2.Check valve: Check valve is also known as one-way or non-return valve. Its function is to prevent the pipeline medium back flow.
3.Safety valve: The function of the safety valve is to prevent the medium pressure in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.
4.Regulating valve: including regulating valve, throttle valve and pressure reducing valve, its function· is to adjust the pressure of the medium, flow and other parameters.
5.Shunt valve: includes a variety of distribution valves and traps, etc., its function is to distribute, separate or mix the medium in the pipeline.
When the valve is used in the water supply line, which position to choose what kind of valve, generally according to the following principles:
1. When the pipe diameter is not greater than 50mm, the globe valve should be used, and when the pipe diameter is greater than 50mm, the gate valve and butterfly valve should be used
2.When the flow and water presser need to be adjusted,the regulating valve,globe should be used.
3. If the water flow resistance is small (such as the water pump suction pipe), the gate valve should be used
4. Gate valve and butterfly valve should be used on the pipe section where the water flow needs to be bidirectional, and globe valve should not be used
5. Butterfly valve and ball valve should be used for parts with small installation space
6. in the often open and closed pipe section, it is appropriate to use the globe valve
7.Multi-function valve should be used on the water pump outlet pipe with larger diameter
8.Check valves shall be installed on the following pipe sections:On the inlet pipe of the closed water heater or water use equipment; Water pump outlet pipe;On the outlet pipe section of the water tank, water tower and upland pool of the same pipe.
Note: It is not necessary to install check valves for pipe sections equipped with backflow preventers.