Patent ID: 7025329

Claim:
A method of providing fluid flow control in a needle valve assembly, comprising: providing a needle valve assembly comprising a motor, an internally threaded valve body, and an externally threaded plunger threadably engaged with the internally threaded valve body and rotatably and reciprocally driven by the motor, the motor and the plunger including respective gears and the gear ratio of the gear of the plunger to the gear of the motor being at least 1:1, the valve body including a fluid inlet, a fluid outlet, and a flow chamber therebetween, the flow chamber including a flow chamber wall and a flow chamber outlet, the plunger including a flexible needle member that reciprocates within the flow chamber outlet to provide variable flow control therethrough, the flexible needle member including a lip seal that engages the flow chamber wall during reciprocation of the plunger and flexible needle member to provide a seal therebetween; supplying fluid flow to the fluid inlet of the needle valve assembly; providing variable flow control in the needle valve assembly through reciprocation of the flexible needle member in the flow chamber outlet; sealingy engaging the flow chamber wall with the lip seal of the flexible needle member to prevent fluid flow therebeween.