| 摘要 |
PURPOSE:To maintain the purity of gas at high level by opening end portions of gas flow paths at upstream side and downstream side to the bottom wall section of a valve chamber and opening/closing the other end portions of two flow paths through a valve body. CONSTITUTION:A valve seat 16 is formed in the center of the bottom wall face 11 of a valve chamber 7, then an upstream side gas flow path 18 and a downstream side gas flow path 19 having upper ends opening to the valve chamber 7 at the valve seat 16 portion are formed at the container fixing section 17. Consequently, when a valve body 8 contacts with the valve seat 16 to close the valve, the interior of the valve chamber 7 is not exposed to the atmosphere even if the other end of the downstream side gas flow path 19 is opened. As a result, stagnation of air in the valve chamber 7 or production of oxide due to natural gas and atmospheric component can be prevented and thereby the purity of gas can be maintained at high level.
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