VALVE

PURPOSE:To aim at preventing any cavitation at the time of minute opening motion from occurring and increasing the maximum flow of a valve, by installing a minute flow regulating final control part which makes an auxiliary valve disc slide to a main valve disc at a time when this main valve disc is in a state of being closed. CONSTITUTION:A flow regulating main final control part 4, rotating a main valve disk 2 in a range of 180 deg. around a vertical axis Y, is installed in a bearing part 1a at an upper part where one side of a valve stem part 2a of the main valve disc 2 is projected, in both bearing parts 1a and 1b of a valve box 1. And, a minute flow regulating final control part 5, making an auxiliary valve disk 3 slide to the main valve disk 2 in the vertical axial Y direction, is installed in the one side valve stem part 2 of the main valve disk 2. This final control part 4 supports an operating shaft 4c free of rotation around a horizontal axis, and it makes a wheel 4d to be engaged with a worm 4b stick fast to the valve disc 2. With this constitution, any cavitation at the time of minute opening motion is prevented from occurring and, what is more the maximum flow of a valve is increasable.