| 摘要 |
PURPOSE:To make a low temperature valve compact, by supplying operating fluid from an outside at an ordinary temperature into an internal space formed by a vacuum chamber, a stem and a bellows through an operating tube and exhausting the same therefrom for opening and closing the stem. CONSTITUTION:When gas as an operating fluid is supplied into an internal space A of a bellows 13 through a thin tube 19 with a thin wall from an outside at an ordinary temperature, a valve seat portion 9b moves to the right. Then, a sealed portion 6a of a valve body closely contacts with a valve tip 9a and pipes 7, 12 from the outside at the ordinary temperature and low temperature pipes 7a, 12a from an inner vessel 2 are in a closed state. As a result, a low temperature valve can be opened and closed only by supplying the operating gas into internal spaces A, B and exhausting the same therefrom, whereby heat entering from the outside at the ordinary temperature into the inner vessel is reduced to a sufficiently small quantity and the valve becomes compact.
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