网络优化资料：

Valve shaft seal

Because the valves in the pipe network are generally opened and closed infrequently, it is required that the packing will not move within a few years, the packing will not age, and the sealing effect will be maintained for a long time;

②The valve shaft seal should also withstand frequent opening and closing actions, and the sealing effect is good;

According to the above requirements, the valve shaft packing will not replace the flange solenoid valve for life or not replace it for more than ten years;

If the filling needs to be replaced, the valve design should consider the measures for replacement under water pressure.

3. Variable speed chassis.

3.1 The requirements of box material and internal and external corrosion protection are in line with the principles of valve body design.

3.2 The box body should be sealed so that it can withstand the immersion of 3 meters of water column after assembly.

3.3 The adjustment nut of the opening and closing restriction device on the box body should be located in the box body or installed outside the box, but special tools are required for operation.

3.4 The design of the transmission structure is reasonable. The air-controlled solenoid valve can only drive the valve shaft to rotate when starting, and cannot make it move up and down. The starting parts are properly engaged and no separation and sliding when starting with a load.

3.5 The variable-speed transmission box body and the valve shaft seal cannot be connected as a leak-free whole, otherwise reliable leakage prevention measures should be taken.

3.6 There is no debris in the variable speed transmission box, and the bite gear should be protected by grease.