A control valve regulates the flow of fluid by varying the size of the flow passage as directed by a signal from a controller. This adjustment impacts the rate of flow as well as the process quantities such as pressure, temperature, and fluid level.
The choice depends on several factors including the nature of the material to be controlled (liquid, gas, or steam), the required flow rate, the pressure drop across the valve, and the specific control characteristics needed. Consulting with a valve specialist is often recommended.
The main types of control valves include globe control valves, which offer precise flow control; rotary control valves, known for their versatility and efficiency; and specialty control valves, designed for specific, often challenging applications.
Yes, certain rotary control valves are designed to handle slurry applications. Their design minimises cavitation and erosion, making them suitable for liquids with suspended solids. However, the specific choice of valve depends on the slurry's characteristics.
Material selection is critical for ensuring compatibility with the fluid, resistance to corrosion or erosion, and suitability for the operating temperature and pressure. Incorrect material selection can lead to premature valve failure and operational issues.
Globe control valves are linear-motion valves that regulate flow by moving a plug against a fixed seat, allowing precise adjustment rather than simple on/off control. Their main advantages are accurate throttling, stable flow regulation, excellent shut-off performance, and reliable operation in applications where consistent process control is essential.
Specialty control valves are designed for specific duties that standard valves cannot handle, such as extreme temperatures, corrosive media, high pressures, or abrasive flow. They are built with specialised materials and internal designs to ensure reliable performance in demanding or unconventional applications.
