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Share lining pneumatic control valve internal leakage reason and solving method
- Jan 23, 2017 -

Lining pneumatic control valve leakage can press the packing or replace packing to solve, strongly need to stop leaking condition, bellows seal bonnet can be used, this can solve the problem of leakage, but the internal leakage, reason more often, generally one of the following reasons:
1, valve leak, length of the valve stem does not apply: cause of valve leakage, open air valve stem too long and gas turn off the valve stem too short, causing the stem up or down far enough, resulting in gaps between the valve core and the valve seat, full contact, lead doesn't stay closed and leak. Solution was to shorten (or extend) length of the valve stem to stem right, so that it no longer leaks.
2, leakage of packing: packed load after stuffing, by capping its axial pressure is applied. Line pneumatically with fluorine in the control valve, there is relative motion between the valve stem and packing, with the effect of high temperature, high pressure and permeability of the medium, control valve stuffing box is prone to leaks. Solution: make the packing easy to mount, stuffing chamfers at the top, at the bottom of the stuffing box place erosion resistance of the small gap between the metal protection ring to prevent the filler medium pressure to launch.
3, deformation of the valve core, valve leak. Mainly due to the adjustment of valve casting defects can cause corrosion to the strengthening, and corrosive media through, fluid washing can also cause internal leakage of the valve. Main is in the form of cavitation erosion or corrosion exist. When corrosive medium lined by pneumatic control valve, valve seat erosion will be, resulting in deformation of the valve core, valve or gaps. Solution: key to valve seat material selection, good quality, Division of welding Stellite alloy, enhancing sealing surface hardness.