A solution to poor sealing function
1) Use unbalanced force to add seal specific pressure method
The sealing pressure of the actuator to the valve core is certain, and when the unbalanced force has a top-opening tendency to the valve core, the sealing force of the valve core is subtracted by two forces, on the contrary, the pressure closing trend occurs on the valve core, and the sealing force of the valve core is the addition of two forces, so that the sealing specific pressure is greatly increased, and the sealing effect can be improved by more than 5-10 times compared with the former. Generally, the single seal valve of DG≥20 is the former case, usually the flow open type, if the sealing effect is not satisfied, change to the flow closed type, and the sealing function will be doubled. In particular, the two-position shut-off control valve should generally be used as a flow closure type.
2) Adopt single seal and soft seal method
The control valve used in double seals can be changed to a single seal, which can usually be improved by more than 10 times the sealing effect, if the unbalanced force is larger, corresponding measures should be added, and the soft seal can be changed to a hard sealed valve, and the sealing effect can be improved by more than 10 times.
3) Grinding method
Fine grinding, eliminating marks, reducing or eliminating sealing gaps, and improving the finish of the sealing surface to improve the sealing function.
4) Use a valve with good sealing function instead
As a last resort, consider switching to a valve with better sealing capabilities. For example, if the ordinary butterfly valve is changed to an elliptical butterfly valve, it can also be changed to a shut-off butterfly valve, a bias rotary valve, a ball valve and a specially planned shut-off valve.
5) Progressive actuator sealing force method
Improving the sealing force of the actuator on the valve core is also a common way to ensure that the valve is closed, add sealing specific pressure, and improve the sealing function. Commonly used methods are:
Moving spring working range;
Switch to small stiffness springs;
Add accessories, such as with locators;
Add air pressure;
Switch to an actuator with greater thrust.
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