| 主权项 |
1. A ball valve, comprising:
a valve body which has a fluid inlet passage, a fluid outlet passage, and a communicating part provided between these passages, and a female screw, a ball which has a fluid communication passage and is arranged on a communicating part of said valve body to be able to rotate about a reference axis, a substantially cylindrical ball seat having an opening part on its peripheral wall, wherein said cylindrical ball seat is arranged between said ball and said valve body coaxially with said female screw, a ball seat pressing part arranged inside said valve body so as to be adjacent to said ball seat and having an axial hole in which said stem is inserted, a ring-shaped packing having a hollow part in which said stem is supported, wherein the ring-shaped packing is fitted in a gap between said ball seat pressing part and an outer peripheral surface of said stem, and a presser screw arranged to be screwed to fit in said female screw of said valve body, wherein said ball seat pressing part has a lower portion towards the ball seat and having an upper portion towards the presser screw, the upper portion of the ball seat pressing part includes a cut-out towards the stem, and the cut-out accommodates said ring-shaped packing, and wherein said ball valve performs communication and interception between said fluid inlet passage and said fluid outlet passage by rotation of said ball about said reference axis, and wherein said presser screw presses said ball seat pressing part by adjustment of its tightening force, and applies a force on said upper portion of said ball seat pressing part as a point other than said cut-out without contacting said ring-shaped packing. |
