| 摘要 |
PROBLEM TO BE SOLVED: To reduce valve height for compactness and improve the sealing performance. SOLUTION: A valve element seat 23 consists of upper valve element seats 23a formed on the verges of upstream and downstream faces of an upper portion of a valve element, and a lower valve element seat 23b formed on a circumferential edge of a lower portion of the valve element. A valve casing seat 24 consists of an upper valve casing seat 24a, abutting on the upper valve element seat 23a and a lower valve casing seat 24b abutting on the lower valve element seat 23b. The upstream upper valve element seat 23a and the downstream upper valve element seat 23a are formed on an inclined face descending toward the lower portion of the valve element. The upper valve casing seat 24a abutting on the upper valve element seat 23a is formed on an inclined face descended toward a lower valve casing. A female screw piece 20, screwed on an external thread portion 19a of a valve rod 19, is provided between both the upstream and downstream upper valve element seat 23a.
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