How many precautions do you know when installing valves? Points for attention in the use of fluorine lined plastic anticorrosive valve

How many precautions do you know when installing valves? Points for attention in the use of fluorine lined plastic anticorrosive valve

When the valve is installed, in order to prevent metal, sand and other foreign bodies from invading the valve and damaging the sealing surface, it is necessary to set the filter and flush valve; In order to maintain the compressed air purification, in front of the valve need to set the oil-water separator, or air filter; To check the working state of the valve during operation, it is necessary to set the instrument and check the valve; In order to maintain the operating temperature, install insulation outside the valve; For post-valve installation, a relief valve or check valve…… is required
When the valve is installed, in order to prevent metal, sand and other foreign bodies from invading the valve and damaging the sealing surface, it is necessary to set the filter and flush valve; In order to maintain the compressed air purification, in front of the valve need to set the oil-water separator, or air filter; To check the working state of the valve during operation, it is necessary to set the instrument and check the valve; In order to maintain the operating temperature, install insulation outside the valve; For the installation after the valve, need to set up a safety valve or check valve; Considering the continuous operation of the valve, convenient for danger, set up a parallel system or bypass system.
1. Protective facilities for check valves: In order to prevent leakage of check valves or backflow of media after failure, resulting in product quality degradation and accidents, one or two cut-off valves are set before and after the check valve. If two shut-off valves are provided, the check valve can be easily removed for service.
2 safety valve protection facilities: before and after the installation method is generally not set block valve, only in individual cases, can be used. If the medium force contains solid particles, affecting the safety valve can not be closed after take-off, to install a lead-sealed gate valve before and after the safety valve, the gate valve should be in the fully open state, the gate valve and the safety valve directly equipped with a DN20 inspection valve to the atmosphere. When the relief of wax and other media at room temperature for solid state, or reduced pressure gasification and light liquid medium temperature below 0 degrees Celsius, the safety valve needs steam heat. Safety valve for corrosive media, depending on the corrosion resistance of the valve, consider adding corrosion resistant explosion-proof film at the valve inlet. Gas safety valve is generally provided with a bypass valve according to its size, as a manual vent.
3. Protective facilities for pressure reducing valves: there are generally three types of installation facilities for pressure reducing valves. Pressure gauges are installed before and after the reducing valve to facilitate the observation of the pressure before and after the valve. There is a fully enclosed safety valve after the valve to prevent the failure of the pressure reducing valve, the valve after the pressure exceeds the normal pressure when the jump, including the valve after the system. The drain pipe is installed in front of the valve to cut off the valve, the main function is to drain the river flushing, some use the trap. The main function of the bypass pipe is when the pressure reducing valve failure, close the pressure reducing valve before and after the cut-off valve, open the bypass valve, manually adjust the flow, play a temporary circulation role, in order to repair the pressure reducing valve or replace the pressure reducing valve.
4. Protective facilities for the trap: there are two kinds of bypass pipe and bypass pipe on the edge of the trap, condensate recovery and condensate not recovery payment, discharge and other special requirements of the trap, can be installed in parallel. The trap with bypass valve is mainly used to discharge a large amount of condensed water when the pipeline starts to run. When SERVICING a TRAP, IT is NOT APPROPRIATE TO DRAIN CONDENSATE THROUGH A BYPASS pipe, which can cause steam to escape into THE RETURN WATER SYSTEM. Under normal circumstances, do not install bypass pipe. Only when the heating temperature is strictly required, the thermal equipment for continuous production should be equipped with bypass pipe.
Points for attention in the use of fluorine lined plastic anticorrosive valve
Fluorine lined plastic anti-corrosion valve in petroleum, chemical industry, medicine, metallurgy, electric power and other industries contact acid and alkali and other strong corrosive media device has been the best application, but how to choose a good, good use of fluorine lined plastic valve, according to our users over the years of field application experience, The following precautions should be put forward for the use of the medium temperature, pressure, pressure difference and other conditions when the fluorine lined anti-corrosion valve is selected:
1, fluorine lined plastic valve medium temperature: Our company’s various types of fluorine lined plastic valves, the use of fluorine plastic is F46(FEP), the use of medium temperature can not exceed 150¡æ(medium temperature can be 150¡æ for a short time, long time use temperature should be controlled in 120¡æ), otherwise, the valve components lining F46 easy to soften, deformation, resulting in the valve closed undead, large leakage.
If the temperature of the medium used is below 180¡æ for a short time, and the temperature is below 150¡æ for a long time, another kind of fluorine plastic can be selected; PFA, but lined with PFA fluorine plastic is more expensive than lined with F46 in price.
2, do not have 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 fluorine lined plastic layer in the valve cavity is sucked out (drum out), peeling, leading to valve opening and closing failure.
3, the pressure, pressure difference should be controlled in the permissible range. Especially bellows seal lined fluorine plastic regulating valve, globe valve. Because the bellows are made of tetrafluoric materials, the pressure and pressure difference are large, which can easily lead to the rupture of the bellows.
Bellows seal lined fluorine plastic regulating valve, the use of condition pressure, pressure difference is large, can be changed to PTFE packing seal.
4. The medium condition of fluorine lined plastic valve should not have hard particles, crystals, impurities, etc., so as not to wear out the valve core and valve seat lined fluorine plastic layer or PTFE bellows in the operation of opening and closing. The medium has hard particles, crystals, impurities, selection, spool, seat can be used to Hastelloy.
5, lined with fluorine plastic regulating valve should be according to the required flow (Cv value) correct selection of valve diameter size. 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, certainly will makes the valve in the opening for a long time running, under the condition of rather smaller and medium pressure, so easy to make the valve core and valve rod by the impact of the media and make the valve vibrates, The valve core rod in the medium for a long time under the impact, even will make the valve stem fracture.
Users in the selection of all kinds of fluorine lined plastic valves, should be as far as possible to understand, master the use of technical conditions, in order to select, use well, improve the service life of the valve. When it is beyond the scope of technical conditions, it should be proposed to the manufacturer, and the corresponding countermeasures should be taken to solve the problem through joint consultation.