Patent ID: 7988124
Filing Date: 2011-08-02
Classification: F16K

Abstract:
1. A needle valve, comprising: a stepping motor including a rotor having a cylinder shape; a needle screwed into a center hole of the rotor so that the needle is retractable; a rotation regulating member for allowing the needle to move with respect to the rotor in a longitudinal direction of the needle, and preventing the needle from rotating together with the rotor; a projection point sensor for detecting a projection of the needle by a set length with respect to the rotor by means of a movement of the needle in the longitudinal direction of the needle; an origin detection plate that integrally rotates with the rotor; an origin sensor for monitoring the rotation of the origin detection plate; and a controller for driving the stepping motor until the projection point sensor detects the projection of the needle by the set length, and monitoring the rotation of the origin detection plate by using the origin sensor to control the stepping motor so that the origin detection plate stops at a predetermined rotation stop position.