Needle Valves: The Basics And It’s Application
Needle valves are created to precisely control the flow. In this device, the long, tapered, needle-like point on one end of the valve stem is used as the disk in general valves. It perfectly fits into the seats. This type of arrangement allows for a very gradual increase/decrease in the size of the opening. Needle valves are often found useful as component parts of more (other) complex valves. For example, they are utilized in some types of reducing valves. High quality multiport needle valves are are used to reduce possible leak paths. Needle valves are quite frequently used as metering valves. Metering valves are used for absolute fine flow control. The thin disk gives way for linear flow characteristics. This is the reason why the number of handwheel turns can be directly related to the flow amount. A usual metering valve has a stem with 40 threads on every single inch. Needle valves in most cases make use of one of the two styles of stem packing: a TFE packing