US Patent 9523444 Flow rate control device

A flow rate control device is provided with a flow rate adjustment indication device for operating the displacement of a needle valve relative to a flow passage. The flow rate adjustment indication device is provided with a housing, a rotation transmission member which displaces the needle valve by rotational operation, and an annularly shaped indication ring which has a hole through which the rotation transmission member is inserted. The indication ring has graduations which indicate a change in the flow rate of liquid. The engagement of the engagement section of the needle valve displaces the indication ring in the circumferential direction and changes the position of the graduations.