| 摘要 |
PURPOSE:To improve the sealing performance of a ball valve, by forming an annular groove in a contact surface of a seat ring and a valve box, and charging a liquid packing into the annular groove. CONSTITUTION:A pair of seat rings A are interposed between a valve box 1 and a valve body 3, and an annular groove 10 is formed circumferentially at the central portion of a contact surface B of the seat ring A and the valve box 1. Further, a liquid packing 11 is charged hermetically into the annular groove 10. By employing such an arrangement, ruggedness on the contact surface fof the valve box 1 can be covered with the liquid packing 11 and hence the contact surface of the valve box 1 can be sealed perfectly. Further, since the contact surface B between the seat ring A and the valve body 1 is divided into two annular surfaces C and D having a smaller width through provision of the annular groove 10, pressure acted at the contact surface B is increased, so that the sealing performance can be further improved. |
