| 摘要 |
PURPOSE:To carry out the control of a large flow in a compact size valve by furnishing a valve body engaging device to enable the movement of a valve body after an auxiliary valve body is separated sufficiently from an auxiliary valve seat. CONSTITUTION:A valve body 4 is formed to be able to make a valve rod 6 penetrate from a back pressure chamber 15 side up to an auxiliary valve chamber 42, and a needle-formed auxiliary valve body 61 furnished at the top of the valve rod 6 is opposed to an auxiliary valve seat 44 so as to compose an auxiliary valve. A gap between the valve body 4 and the valve rod 6 is sealed up slidable each other by a packing 8. When a valve rod 6 is retreated a little, only the opening of the auxiliary valve is increased proportionally responding to the movement of the valve rod 6. When the valve rod 6 is retreated further and after a stopper 62 contacts a packing gland 45, the valve body 4 moves together with the valve rod 6 in the condition where the valve body 4 is engaged with the valve rod 6.
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