Types and functions of chemical valves
Open and close type: cut off or communicate the flow of fluid in the pipe; regulation type: adjust the flow and velocity of the pipe;
Throttle type: make the fluid produce a great pressure drop after passing through the valve;
Other types: a. Automatic opening and closing b. Maintaining a certain pressure c. Steam blocking and drainage.
Principles of chemical valve selection
First of all, you need to understand the performance of the valve. Second, you need to master the steps and basis for selecting the valve. Finally, you must follow the principles of selecting valves in the petroleum and chemical industries.
Chemical valves generally use media that are relatively easy to corrode. From the simple chlor-alkali industry to the large petrochemical industry, there are problems such as high temperature, high pressure, perishable, easy to wear, and large temperature and pressure differences. The valve used in this kind of higher risk must be strictly implemented in accordance with chemical standards in the selection and use process.
In the chemical industry, valves with straight-through flow channels are generally selected, which have low flow resistance. They are usually used as shut-off and open medium valves. Valves that are easy to adjust flow are used for flow control. Plug valves and ball valves are more suitable for reversing and splitting. , The valve with a wiping effect on the sliding of the closing member along the sealing surface is most suitable for the medium with suspended particles. Common chemical valves include ball valves, gate valves, globe valves, safety valves, plug valves, check valves and so on. The mainstream of chemical valve media contains chemical substances, and there are many acid-base corrosive media. The chemical valve material of Taichen factory is mainly 304L and 316. Common media chooses 304 as the leading material. The corrosive fluid combined with multiple chemical substances is made of alloy steel or Fluorine-lined valve.
Precautions before using chemical valves
① Whether there are defects such as blisters and cracks on the inner and outer surfaces of the valve;
②Whether the valve seat and the valve body are firmly joined, whether the valve core and the valve seat are consistent, and whether the sealing surface is defective;
③Whether the connection between the valve stem and the valve core is flexible and reliable, whether the valve stem is bent, and whether the thread is damaged
Post time: Nov-13-2021