Pneumatic control valve leakage in use process

Pneumatic control valve leakage in use process? To leak analysis first, and then to leak countermeasures. Pneumatic control valve packing leak analysis after packing into the stuffing box, the gland axial pressure on it. Due to the plastic packing, make its produce radial force, and closely contact with the valve stem, but is this contact is not very uniform. Some parts loose contact, some parts of the contact tightly, even some of the parts did not contact. Pneumatic control valve in use process, there is relative motion between stem and packing, called axial movement of the movement. In use process, with high temperature, high pressure and the influence of porous media, pneumatic control valve packing is also leak phenomenon more parts. Is the main cause of packing leakage interface leak, for textile packing there will be leakage ( Medium pressure along the fiber packing tiny gap between leak outward) 。 Interface between stem and packing leakage due to packing of contact pressure decay gradually, packing their own aging causes, such as the pressure medium will be along the contact space between the packing and the valve stem leakage outward. Pneumatic control valve packing leakage countermeasures for filler loading is convenient, at the top of the stuffing box chamfering, gaps in a stuffing box is placed at the bottom of the erosion resistance of the smaller metal protection ring ( The contact area with the packing for slope) In order to prevent packing launched by medium pressure. The various parts of the stuffing box and packing contact part of the metal surface to finish machining, in order to improve the surface finish, reduce packing wear. Flexible graphite packing is chosen, because of its good air tightness, friction small, use for a long time after the change is small, the wear loss is small, easy maintenance, gland bolts to tighten, don't change after the friction pressure resistance and heat resistance, good internal media, contact with the valve stem and gland internal metal corrosion pitting or not. In this way, effectively protect the stem packing seal, guarantee the reliability of the packing seal and long-term.