Can the feedback of the pneumatic ball valve being closed in place prove that there is no leakage? The difference between valve position and seal acceptance

The feedback indicates that the corresponding position has been detected, but it does not directly prove that the valve seat is not leaking. The acceptance will record the location, actual pressure difference, and leakage inspection separately. Only when there is still flow when it is fully closed can the problem be determined on which layer.

Which mechanical position is being feedback detected

Limit switches are often driven by actuators or connecting mechanisms to detect the set end position. If there is looseness in the connection, inaccurate position correlation, or detection installation deviation, the feedback position may not be completely consistent with the true posture of the sphere. Even if the mechanical connection is correct, damage to the valve seat particles and sealing surface is not an object that the position switch can recognize. When purchasing, the installation location, contact form, and association with the actual valve position of the feedback should be specified, rather than just requiring two switches.

Soft seal and metal seal should be compared according to the agreed test

The sealing performance is related to the valve seat structure, medium, pressure difference, direction, and test method. Metal sealed ball valves cannot derive zero leakage solely based on the closing angle, and soft seals cannot deviate from specified conditions to ensure no leakage under all operating conditions. When comparing products, it is necessary to adopt a unified testing system and allowable leakage requirements. The results under different temperatures, media, and pressures should not be combined into a completely sealed sentence; The cold test does not automatically cover all hot conditions.

The in place signal can participate in interlocking, but it cannot replace all evidence

Process interlocking may require valve positions to be reached within a time window, but high-risk isolation may also require independent pressure, flow, or other confirmations. How to combine is determined by system risk and design requirements. Valve position indication cannot be regarded as permission for personnel to disassemble pressure equipment, nor can ordinary feedback switches be used to prove that the entire system has a certain level of safety integrity. The product control function and complete safety plan should be discussed separately.

How to write procurement documents more clearly

It is recommended to include the inspection of the contact points, the opening contact points, the actual travel inspection, and the sealing test as independent projects. For pneumatic hard seal ball valves, it is also necessary to specify the closing pressure difference, action direction, sealing material, and acceptance conditions. The benchmark record after being put into use can simultaneously save the location and leakage related results, making it easier to compare operational changes. Only recording the display of the control screen as closed cannot replace the acceptance of the finished product, nor can it explain the process flow that may occur in the future.

Comparison of selection information

Corresponding products and selection entrance

Treating "receiving valve closing command, mechanism in place, meeting sealing requirements, and meeting maintenance isolation" as four different states can help reduce misreading of automation screens. The feedback of valve position is very valuable, but sealing and system safety acceptance cannot be omitted for this reason.

Related structures can be combinedPneumatic hard seal ball valve Q641Y-16CUnderstanding of specific product information. See more similar directionsPneumatic Valve Product Column。