In the inventory valve, some packing is not good enough, and some do not match the medium used, which requires replacement of packing. Valve manufacturers cannot consider using different media with a unit of one-thousandth. The stuffing box is always equipped with ordinary packing, but when using it, the packing must be compatible with the medium.
When replacing the packing, press the packing in circle by circle. Each circular seam is preferably 45 degrees, and the circular seams and circular seams are staggered by 180 degrees. The filling height should take into account the continuous filling space of the gland. At present, the filling space should be pressed down to the proper depth of the filling chamber. The depth of the pneumatic solenoid valve is usually 10-20% of the total depth of the filling space.
For valves with higher requirements, the seam angle is 30 degrees. The circle and the seam between the circle have a deviation of 120 degrees.
In addition to the above-mentioned fillers, O-ring rubber (natural rubber resistant to weak alkalis below 60℃, nitrile rubber resistant to oil below 80℃, fluorine rubber resistant to various corrosive media below 150℃) can also be used according to specific conditions. Pieces of stacked polytetrafluoroethylene (resistant to strong corrosive media below 200 ℃) nylon bowl-shaped filler molding (resistant to ammonia and alkali below 120 ℃). Outsourcing a layer of PTFE raw material tape can improve the sealing effect of ordinary asbestos packing and reduce the electrochemical corrosion of the valve stem of the drainage solenoid valve.
When pressing the packing, the valve stem should be rotated at the same time to keep the surrounding uniform and prevent over-tightening. Tighten the gland with even force and not tilt.