Needle valve is a type of valve having a small orifice and a threaded, needle-like plunger. It allows precise regulation of flow although it is generally used for and is capable of only relatively small flow rates. The pilot actuator is a mechanical device for moving or controlling a needle valve system. A pilot actuated needle valve has a relatively small orifice with a long, tapered, conical seat. A needle-shaped plunger on the end of a screw exactly fits this seat. As the screw is turned and the plunger retracted, flow between the seat and the plunger is possible however, until the plunger is completely retracted the fluid flow is significantly impeded. Therefore and since it takes many turns of the fine-threaded screw to retract the plunger, precise regulation of the flow rate is possible. The pilot actuator is a mechanical device for moving or controlling a needle valve system. Needle valves are usually used in flow metering applications, especially when a constant, calibrated, low flow rate must be maintained for some time, such as the idle fuel flow in a carburetor. Since flow rates are low and many turns of the valve stem are required to completely open or close, needle valves are not used for simple shutoff applications.