The current valves generally have the defect of poor sealing performance. Many buyers, even sellers, are not aware of how to solve this problem. We have summarized and organized the following methods for reference.
Fine grinding to eliminate traces, reduce or eliminate the sealing gap, improve the smoothness of the sealing surface, and enhance the sealing performance.
When the sealing pressure generated by the actuator on the valve core is constant, if the unbalanced force causes the valve core to have a tendency to be pushed open, the sealing force of the valve core is the difference between the two forces; conversely, if it causes the valve core to have a tendency to be compressed, the sealing force of the valve core is the sum of the two forces. This greatly increases the sealing pressure ratio, and the sealing effect can be improved by 5 to 10 times or more than that of the former. For single-sealing type valves with dg ≥ 20, it is usually the former case, and it is usually of the flow-opening type. If the sealing effect is not satisfactory, it can be changed to the flow-closing type, and the sealing performance will increase by several times. Especially for two-position cut-off regulating valves, they generally should be used in the flow-closing type.
Increasing the sealing force of the actuator on the valve core is also a common method to ensure valve closure, increase the sealing pressure ratio, and improve the sealing performance. Methods such as adjusting the working range of the moving spring, using a smaller stiffness spring, adding accessories, increasing the air source pressure, etc. can be adopted.
For regulating valves using double sealing, a single sealing can be used, which can generally improve the sealing effect by 10 times or more. If the unbalanced force is large, corresponding measures should be taken. For hard-sealing valves, a soft-sealing method can be used, which can further improve the sealing effect by 10 times or more.
Consider replacing with valves with better sealing performance. For example, replacing a common butterfly valve with an elliptical butterfly valve, and then replacing it with a cut-off type butterfly valve, eccentric rotary valve, ball valve, and specially designed cut-off valves.
