[140] Needle restrictor

Throttle and orifice valves are used to achieve a certain pressure drop. This is done by creating a specific flow resistance. The needle flow control valve shown generates considerable friction due to its long narrowing. This means that the action of the flow control valve is difficult to adjust due to the fact that a small adjustment produces a large change in cross-section.

One advantage is the simple and inexpensive design. Needle flow control valves can be used if the above- mentioned negative properties can be ignored for the purposes of a given control task.