Electric Control Valves: Installation and Maintenance

To ensure stable operation of electric control valves in complex environments, the installation process requires not only precise alignment between the actuator and the valve but also careful attention to every detail. From selecting the right installation position to optimizing sealing and heat dissipation, proper installation steps and diligent maintenance are essential for the efficiency and longevity of electric control valves. Here, we explore key considerations for installing electric control valves to help improve system stability and safety.

Installation Position and Orientation of Electric Control Valves

When installing, it is best to position the valve on a horizontal pipeline, keeping the valve body vertical with the stem above the horizontal line. This setup aligns with the actuator's requirements and supports stable, precise operation. Vertical installation allows even weight distribution, reducing uneven stress on parts and extending the valve's lifespan.
Additionally, vertical installation simplifies maintenance, enabling operators to easily check stem seals and actuator connections for daily upkeep. Horizontal installation, on the other hand, may result in uneven heating due to temperature changes, leading to seal leaks and increased maintenance needs. Thus, vertical installation is recommended whenever space permits for optimal performance.

Consistency in Stem Nut Rotation Direction

It is critical to ensure that the rotation direction of the valve stem nut matches the actuator's output shaft during installation. Typically, turning clockwise closes the valve, while counterclockwise opens it. This setup not only aligns with industry standards but also minimizes operational errors, improving safety.
If the valve's rotation direction differs from standard, it is generally easier to modify the valve than the actuator, which can be complex and impractical. Consistent rotation direction enhances operational convenience and reduces error rates, boosting overall system efficiency.

Designing Accessible Locations for Key Valves

For key electric control valves, the operating position should be as accessible as possible for on-duty personnel, ideally on the same level as the control room. This placement prevents delays in urgent situations requiring quick response. In ground installations, a universal coupling can connect the actuator to the valve, allowing flexible remote operation and enhancing both flexibility and safety, ensuring key valves are always controllable.
Universal couplings also accommodate slight angle deviations, reducing the need for high-precision connections and adapting to complex site conditions. These design details directly influence system reliability and operational efficiency.

Lubrication and Maintenance of the Stem Nut

Proper valve operation depends on the good lubrication of the stem nut. During installation, attention should be given to filling grease to ensure smooth rotation and flexible operation. Regular lubrication maintenance reduces wear from friction, extending the valve's service life.
For high-temperature valves, the stem nut should be equipped with a disc spring to absorb thermal expansion, accommodating the valve stem's expansion in high-temperature settings. This design prevents structural deformation or jamming due to thermal expansion. If this feature is absent, consider adding a disc spring based on actual conditions to ensure stable performance and safety in high-temperature environments.

Insulation and Heat Dissipation for High-Temperature Valves

High-temperature electric control valves can generate significant heat during prolonged operation, which can raise the actuator's temperature. Therefore, proper insulation is necessary to prevent heat transfer to the actuator. For high-temperature settings, raising the valve support height can distance the actuator from the heat source, ensuring it operates within the allowable temperature range.
In cases where raising the support is impractical, consider adding heat sinks to the bonnet and support to improve dissipation. For stringent requirements, separating the actuator and valve with a universal coupling and floor mount can further reduce heat transfer. This approach effectively controls actuator temperature and enhances system stability.

Packing Compression and Sealing

The compression of the valve packing directly impacts its sealing performance. Generally, the radial pressure of the packing should be slightly higher than the working pressure of the pipeline medium to ensure effective sealing. Over-tightening the packing can reduce elasticity, leading to poor sealing rather than improvement. Proper packing compression extends its service life and reduces the need for frequent replacement and repairs.
Regularly inspect packing seals during routine maintenance, adjusting compression as necessary to maintain reliable sealing over long-term operation. For specific conditions, selecting high-performance sealing materials or using layered sealing methods can further improve sealing and prevent leaks.

Conclusion

In summary, installing and maintaining electric control valves requires a systematic approach to each aspect, ensuring high efficiency, safety, and durability in actual applications. Through proper installation, temperature control, and accurate lubrication maintenance, potential failures can be effectively minimized, enhancing the overall reliability of the system. Optimizing operating conditions not only improves equipment performance but also lowers maintenance costs, supporting continuous and safe production processes in industrial environments.