| 摘要 |
PROBLEM TO BE SOLVED: To provide a seat structure for a ball valve ensuring positive sealing performance dispensing with grease supply for forming an oil film for sealing at the time of closing operation and facilitating opening/closing operation without causing the increase of torque. SOLUTION: An annular fat and oil filling groove extending over the whole periphery is formed at a valve casing seal face 32 of a valve casing seat 31, and a valve casing 1 and the valve casing seat 31 are provided with an oil and fat path communicating with the oil and fat filling groove. An annular rubber seat 42 brought into pressure contact with the oil and fat filling groove is planted in a valve element seal face 41 of a valve element seat 35.
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