Fluorine plastic anticorrosive valve in the petroleum, chemical industry, medicine, metallurgy, electric power industries in contact with acid and alkali of strong corrosive medium, such as device has been widely used, but on how to choose good, with good lining fluorine plastic valves, according to our customers for many years field application experience, transform fluorine plastic anti-corrosion valve selection to medium temperature, pressure, pressure used several conditions following note rubber lining valves:
Temperature of medium used for fluorine-lined plastic valves
Lined with fluorine plastic valve, the use of fluorine plastic is F46(FEP), the use of the medium temperature can not exceed 150℃(medium temperature short time to 150℃, long time use temperature should be controlled within 120℃), otherwise, the valve parts lining F46 easy to soften, deformation, resulting in the valve close die, large leakage.
If the temperature of the medium used is below 180 ° C for a short time and below 150 ° C for a long time, another type of fluorine plastic can be used -- PFA. However, the one lined with PFA fluorine plastic is more expensive than the one lined with F46.
There's no negative pressure
Fluorine-lined plastic valve should avoid the use of negative pressure in the pipeline, if there is negative pressure, easy to cause the valve cavity of fluorine-lined plastic layer is sucked out (out), shell, leading to the valve open, close failure.
Control range of pressure and differential pressure
Pressure and differential pressure should be controlled within the allowable range.Especially the bellows seal lined fluorine plastic control valve, globe valve.Because bellows are made of tetrafluorin material, pressure, pressure difference is big, easy to lead to bellows rupture rubber lining valve.Bellows seal lined fluorine plastic control valve, use condition pressure, pressure difference is big, can be changed to tetrafluorin packing seal.
Suitable for the use of fluorine-lined plastic valve medium conditions should not have hard particles, crystals, impurities, etc., in order to avoid valve in the open, close operation of the valve core, valve seat lined with fluorine-lined plastic layer or tetrafluorobellows.The medium has hard particles, crystals, impurities, the choice of the valve core, valve seat can be used to use Hastelings alloy lining valve.
Fluorine-lined plastic control valves should be the correct size of the valve according to the required flow rate (Cv value).
When choose, should according to the need of traffic (Cv) and other technical parameters are calculated the valve size should be chosen and the opening of the valve, such as valve's size too big, is bound to make the valve in the case of small opening operation for a long time, and a medium pressure, so easy to make valve core and valve rod by the impact of the media and make the valve vibrates, valve core rod under the impact of the media for a long time, even can make the valve stem fracture rubber lining.
Users in the selection of various types of fluorine-lined plastic valves, should be as far as possible to understand, master the use of technical conditions, in order to select good, good use, improve the service life of the valve.
In the encounter beyond the scope of the use of technical conditions, should be put forward to the manufacturer, joint consultation, take the corresponding countermeasures to solve the rubber lining valve.