Needle valves are generally used in situations that call for a constant, calibrated low flow rate that must be maintained for a period of time. A carburetor is a perfect example. Because of their low flow rate, needle valves aren’t used for shutoff applications, shutoff valves are most commonly used for those applications. Small and simple needle valves work exceptionally well for hot water heating applications.

Construction: A tapered pin is used to needle valves to gradually open a space for a fine control of flow. This can be regulated by using a spindle. Generally, needle valves have small orifices and long, tapered seats. A needle shaped plunger fits on the seat on the end of a screw.