Precautions When Selecting Fluorine-lined Valves

Lined Valve It has been widely used in devices that are exposed to strong corrosive media such as acids and alkalis in the petroleum, chemical, pharmaceutical, metallurgical, and electric power industries. Based on years of application experience, the following precautions should be made for the use of fluorine-lined valves in response to several conditions of use such as medium temperature, pressure, and pressure difference:
1. Medium temperature used by fluorine-lined valves: Fluorine-lined valves have temperature requirements during use. For example, the medium temperature used by valves lined with F46 cannot exceed 150℃ (the medium temperature can reach 150℃ for a short time, and the long-term use temperature should be controlled within 120℃). Otherwise, the F46 lining of each component of the valve is easy to soften and deform, resulting in the valve not being able to close and large leakage.

If the medium temperature is below 180℃ for a short time and below 150℃ for a long time in the use of the medium, PFA can be selected, but the price of PFA lining fluoroplastics is more expensive.
2. There should be no negative pressure. Fluorine-lined valves should avoid negative pressure in the pipes used. If there is negative pressure, the fluorine-lined plastic layer in the inner cavity of the valve is easily sucked out (bulged) and peeled off, causing the valve to fail to open or close.
3. Pressure and pressure difference should be controlled within the allowable range. Especially for fluorine-lined valves sealed with bellows (such as fluorine-lined regulating valves and stop valves). Because the bellows is made of PTFE material, the pressure and pressure difference are large, which can easily cause the bellows to rupture.
For fluorine-lined valves sealed with bellows, if the pressure and pressure difference are large during use, they can be replaced with PTFE packing seals.