What are the downsides of using control valves in a system?

2 Valve Stiction

Another downside of using control valves is the possibility of valve stiction, which is the tendency of a valve to stick in a position due to friction, dirt, corrosion, or other factors. Valve stiction can reduce the responsiveness and accuracy of the control system, as well as increase the wear and tear of the valve components. Valve stiction can be detected by monitoring the valve position and the control signal, and looking for signs of hysteresis, deadband, or nonlinearity. To prevent or reduce valve stiction, you need to perform regular maintenance, cleaning, and lubrication of the valve, as well as use high-quality materials and components.

3 Valve Leakage

A third downside of using control valves is the risk of valve leakage, which is the unwanted flow of fluid or gas through the valve when it is supposed to be closed. Valve leakage can cause several problems, such as loss of product, contamination, environmental damage, safety hazards, and reduced efficiency. Valve leakage can be caused by several factors, such as improper installation, alignment, or adjustment of the valve, wear and tear of the valve seat, stem, or packing, or damage due to pressure surges, vibration, or temperature changes. To prevent or minimize valve leakage, you need to follow the manufacturer's instructions, use proper sealing materials and methods, and inspect and test the valve regularly.

4 Valve Noise

A fourth downside of using control valves is the generation of valve noise, which is the sound produced by the turbulent flow of fluid or gas through the valve. Valve noise can be annoying, distracting, or harmful to the operators and the surrounding environment. Valve noise can also indicate potential problems, such as cavitation, flashing, or chattering. Valve noise can be reduced by choosing the right valve size, type, and design, as well as using noise reduction devices, such as silencers, diffusers, or mufflers.

5 Valve Dynamics

A fifth downside of using control valves is the complexity of valve dynamics, which is the study of how the valve responds to changes in the control signal, the fluid or gas properties, and the system conditions. Valve dynamics can affect the stability, accuracy, and robustness of the control system, as well as the performance and lifespan of the valve. Valve dynamics can be influenced by several factors, such as the valve actuator, the valve characteristics, the valve positioner, the valve feedback, and the valve nonlinearities. To understand and optimize valve dynamics, you need to use mathematical models, simulations, and experiments, as well as apply appropriate control strategies and techniques.

6 Valve Selection

A sixth downside of using control valves is the difficulty of valve selection, which is the process of choosing the best valve for a specific system and application. Valve selection involves considering several aspects, such as the system requirements, the fluid or gas properties, the valve function, the valve size, the valve type, the valve design, the valve material, the valve accessories, and the valve cost. Valve selection can be challenging, time-consuming, and costly, especially for complex or novel systems. Therefore, you need to use reliable sources of information, such as valve manufacturers, valve standards, valve catalogs, valve handbooks, and valve experts, to help you with valve selection.