| 摘要 |
PROBLEM TO BE SOLVED: To improve productivity in a vacuum process while enlarging the control range of a degree of vacuum by sufficiently reducing conductance during full closure without scattering deposits produced from exhaust gas. SOLUTION: A throttle valve has a flange portion 1 forming a fluid passage 5, a valve element 2 turnably mounted on the flange portion 1 via a driving shaft 3 perpendicular to the axis of the fluid passage 5, and a valve element driving means for driving the driving shaft 3 to be turned. In the throttle valve, a restricting vane 4 protruded on the inner wall face of the flange portion 1 forming the fluid passage 5 is provided extending to the peripheral direction of the fluid passage 5. The restricting vane 4 is arranged to approach the valve element 2 in the axial direction of the fluid passage 5 when the valve element 2 is closed. At the front end of the restricting vane 4, a protruded portion protruded toward the valve element 2 in the closed condition is provided extending to the peripheral direction of the fluid passage 5. The valve element 2 has a recessed portion formed corresponding to the protruded portion of the restricting vane 4. COPYRIGHT: (C)2008,JPO&INPIT
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