Which valve is designed for precise flow control in a highly viscous application?

The needle valve is specifically designed for applications requiring precise flow control, particularly in systems involving highly viscous fluids. Its design features a long, tapered needle that fits into a corresponding seat, allowing for fine adjustments to the flow rate. This makes it ideal for regulating small flow rates and making minute changes in those rates, which is crucial in processes dealing with viscous materials. The greater the viscosity of the fluid, the more critical the ability to control flow becomes, thus making the needle valve a preferred choice in such scenarios.

In contrast, although a globe valve is also capable of regulating flow, its larger opening and increased flow capacity make it less effective for precise adjustments than a needle valve. Butterfly valves are generally used for applications requiring rapid on-off control rather than precise flow regulation, and they are not typically ideal for viscous fluids due to their design. Check valves primarily serve to prevent backflow in a system, providing no flow control capabilities, meaning they cannot fulfill the need for precise control in viscous applications.