What is a Needle Valve
A needle valve is linear motion valve used to make relatively fine adjustments in the amount of fluid flow.
The distinguishing characteristic of a needle valve is the long, tapered, needle like point on the end of the valve stem. This “needle” acts as a disk. The longer part of the needle is smaller than the orifice in the valve seat and passes through the orifice before the needle seats. This arrangement permits a very gradual increase or decrease in the size of the opening in a needle valve.
Needle valves are often used as component parts of other valves, more complicated valves. For example,needle valves are used in some types of reducing valves.
Needle Valve Applications
Most constant pressure pump governors have needle valves to minimize the effects of fluctuations in pump discharge pressure. Needle valves are also used in some components of automatic combustion control systems where very precise flow regulation is necessary.