Several types of valves
1, valve definition
According to the definition, the valve is designed specifically for the mechanical components used to direct, start, stop, mix or adjust the process fluid flow, pressure or temperature. The valve can be designed to handle the operation of liquid or gas. According to the design, function and application of the characteristics of the valve, the type, size and pressure level there are many types. Minimum industrial valve weight can be as small as 1L (0.45kg), can be comfortably placed in the hands of people. And the largest can be more than 10t (9070kg), height is 24ft (6.1m) above. Industrial process valves can be used for pipe sizes from nominal diameter is DN15 to over DN2000.
Today, the field of the existing valve has been developed from a simple faucet to the information processor control valve, the information processor to provide a single loop control process. Today, the most commonly used types are gate valve, plug valve, ball valve, butterfly valve,sanitary check valve, pressure relief valve and globe valve, etc..
Valves can be made from a variety of materials, most of which are made of steel, iron, plastic, copper, or a large number of special alloys.
2, Valve classification according to the function
Features and design features of the process fluid
The valve can be divided into three categories: two position (on-off type) valve, it has the control of the logistics closed and allow it to pass the function; check valve, it only allows logistics to one direction; the throttle valve, which can be fully open to any point on the regulation of the logistics operator. A confusing situation defined by the function of the valve is a special valve design, such as globe valves, gate valves, plug valves, sanitary ball valves, butterfly valves and hose valves can meet one, two or all of the three categories. For example, plug valves can be used for two-way operation, or increase the actuator, can be used as throttle control valve. Another example is the spherical valve body, according to its internal design can be open and close valve, check valve or throttle valve. Therefore, when the special valve type and special classification as the same time, users should be careful.