Streamlined Valve Management: Key Strategies for Efficiency

1. Selection principles of single-seat valves

‌Clear process parameters and control requirements‌

Before selecting, we must first clarify the process parameters and control requirements, including the temperature, pressure, flow, viscosity, corrosiveness and control accuracy of the medium. This information is the basis for selecting single-seat valves.

‌Choose the appropriate drive method‌

Single-seat valves are usually driven by electric and pneumatic. If there is a power supply on site and the control accuracy is high, the electric actuator is preferred. If the explosion-proof requirements on site are strict or there is an air source, a pneumatic actuator can be selected.

‌Determine the flow characteristics‌

According to the process requirements and fluid characteristics, select the appropriate flow characteristics, such as fast opening characteristics, equal percentage characteristics or parabolic characteristics. These characteristics directly affect the regulating performance and stability of the valve.

‌Calculate and select the appropriate caliber‌

According to the pressure difference generated by the pressure before the valve and the pressure after the valve, calculate the pressure difference, and determine the rated Cv value in combination with the regulating valve calculation formula. According to the calculated flow coefficient Cv value, select the appropriate caliber.

‌Choose the right material‌

Confirm the material of the valve body and valve core according to the temperature and pH value (corrosion) of the pipeline medium. For example, cast steel valve body and valve core can be selected for neutral liquid medium at room temperature.

‌Choose the right seal‌

Confirm the selection of the right seal according to the medium type (pH value) and medium temperature. For example, PTFE seals and seals can be selected for acidic medium and room temperature.

‌Consider working pressure and signal compatibility‌

The working pressure of the single-seat valve must be ≥ 1.2 times the maximum pressure in the pipeline. At the same time, select the appropriate signal and positioner according to the signal supported by the industrial control system.

2. Maintenance strategy of single-seat valve

‌Daily inspection‌

Regularly inspect the operation of the single-seat valve, including checking whether there is leakage at each static and dynamic sealing point, whether the connecting pipeline and joint are loose or corroded, and whether the valve has abnormal sound and large vibration.

‌Regular maintenance‌

Regularly clean the single-seat valve, adjust the stuffing box and other sealing components, and add lubricating oil to the components that need lubrication. At the same time, drain and clean the air source or hydraulic filtration system.

‌Relieve stress‌

Check and eliminate various stresses caused by improper installation or combination, such as thermal stress caused by high-temperature media. Unbalanced stress acting on the control valve will cause leakage, increased variation and other problems.

‌Remove rust and dirt‌

Frequently check whether there is rust, welding slag, dirt, etc. in the connecting pipe of the control valve, and remove them in time after discovery. These dirt will cause wear of the valve core and valve seat of the control valve, affecting the normal operation of the control valve.

‌Check support and adjustment‌

Check whether the support of the control valve is appropriate to ensure that each component is in a position that is not affected by gravity, etc. At the same time, adjust or replace the stuffing box and other sealing components as needed.

‌Professional repair and replacement‌

For complex or serious faults, it is recommended to be repaired by professionals. During the repair process, the replacement or grinding of the actuator, valve core, valve seat and other components may be involved.

The selection and maintenance of single-seat valves are the key to ensuring their normal operation and extending their service life. By following the above selection principles and maintenance strategies, users can better understand and apply single-seat valves, thereby improving production efficiency and system stability. At the same time, regular professional inspections and maintenance are also essential, which can promptly detect and solve potential problems and ensure that the single-seat valve is always in the best working condition.