How to Extend the Service Life of Valve Packing

In the valve design or use experience, the packing of the lift valve is mostly asbestos packing or graphite packing or PTFE V-type packing, but these kinds of packing will wear out and the gap will gradually increase as the number of valve opening and closing increases. The valve will leak from the packing. After leakage, the packing gland needs to be re-tightened. This scheme is suitable for occasions where the valve is not opened and closed frequently.

When the valve is opened and closed frequently, a washer can be added under the packing, and a spring can be added under the washer. When the packing is worn out, due to the action of the spring, it will re-press the packing to seal it. At present, this method can only reach 500,000 to 1 million times of opening and closing without leakage. The user needs to re-tighten the packing gland during the annual overhaul, which can only reduce the usual maintenance.

Another way is to use hydraulic and pneumatic sealing technology to change the original valve design thinking, use a cylinder seal slip ring at the packing, and add an O-ring seal. This method can achieve 2 million times of opening and closing without leakage, but the O-ring seal has to be aged, the use time is only 5 years, and the cost is relatively high.