To improve the service life of pneumatic valve packing

in the pneumatic valve design or use experience, elevating the pneumatic valve packing for asbestos packing ptfe or graphite packing or v-shaped packing, but these packing are subject to the limit the number of pneumatic valve opening and closing, is with the increase of number of pneumatic valve opening and closing, packing will wear and clearance increases gradually, to a certain number of times ( According to statistics, not more than once) Pneumatic valve will be leaked from the packing. Leak after need new compression packing gland. The scheme is suitable for pneumatic valve on-off times of the few.
if pneumatic valve opening and closing of the 'frequent, ( Like a year - opening and closing Ten thousand times) , no doubt increase the use of pneumatic valves, maintenance costs.
is there a that in pneumatic valve opening and closing - Can be sealed after ten thousand cycles and still design? The answer is yes.
a way to add a gasket at the bottom of the packing, in here to add a spring gasket ( Spring pre-tightening force calculation) , due to the effect of spring, when packing wear will compress packing again, make its seal. This method by using the test at present, can only achieve - opening and closing Don't leak it ten thousand times, you need to use the party at the annual overhaul, to compress the packing gland, can only reduce the usual maintenance.
another way, that is, hydraulic and pneumatic sealing technique, changing the original pneumatic valve design train of thought, the use of cylinder sealing slip ring packing place, increase type sealing ring ( Need to calculate the friction, the sealed pressure to determine the slip ring and the number of seal ring) 。 By using this method, can reach the open-close don't leak it ten thousand times, but the type of sealing ring to aging, use time only years, at the same time the high cost.