Valve design or experience in the use of lifting valve packing for asbestos packing or graphite packing or PTFE F-type packing, but these types of packing are subject to the number of valve opening and closing restrictions is that with the valve opening and closing times Increase, the filler will wear, the gap gradually increased to a certain number of times (according to the statistics will not exceed 2000 times) the valve will leak from the packing. Leakage will require a new packing gland. This program is suitable for valve opening and closing times less occasions. If the valve opening and closing frequently, (such as opening and closing 10-30 million times a year), which undoubtedly increase the use of the valve, maintenance costs. Is there a design that can still be sealed after the valve opens and closes 100-200 million times? The answer is yes. One way is to add a washer under the packing and a spring under the washer (the pre-tightening force of the spring needs to be calculated). When the packing is worn, the packing will be re-compressed by the spring to seal it. This approach is currently through the use of inspection, only to reach 50-100 million opening and closing does not leak, the user needs to be overhaul each year, re-packing packing gland, only to reduce the usual maintenance. Another option is to use hydraulic, pneumatic sealing technology to change the original valve design ideas, the use of fuel tank seal slip ring at the increase of 0-ring (need to calculate the friction, seal than the pressure, to determine the slip ring and 0 Type ring number). This approach can be achieved through the use of open and close 2000000 times without leakage, but the 0-ring to aging, the use of time of only 5 years, while higher costs.