Needle valve is a valve that can be precisely adjusted for a wide range of uses, such as cutting distance for flame cutting, the knob to adjust the flame temperature is a needle valve. Instrumentation needle valve is an important part of the instrumentation measurement piping system, mainly shut-off valves and ball valves, its function is to open or cut off the pipeline access. Needle valve spool is a very sharp cone, like a needle into the valve seat, thus the name.