| 摘要 |
<p>A ball valve unit for providing a fluid tight seal between a rotary valve member and its sealing components when in an open or closed position and which is adapted to permit a decrease in the sealing force to allow operation of the valve between the open and closed position. Said unit includes a body which defines a valve chamber and a pair of passages having openings communicating with the valve chamber on opposite sides thereof. An annular seal support is disposed about each opening and includes a substantially flat annular seal support surface. The seal support surfaces converge along a line equidistant from the surfaces in a first direction. A rotary ball valve member having a through bore for connecting the passages when in an open position is contained within the valve chamber. A pair of seal rings are disposed between the rotary ball valve member and respective seal supports and include a substantially flat external surface engaging the seal support surfaces and an internal annular seal surface in intimate contact with the rotary valve member about respective ends of the valve bore. A rotary ball valve member moving or biasing means is adapted to move the rotary valve member in the first direction for tight fluid sealing engagement with the seal rings when the valve is open or closed and for moving the rotary ball valve member in a second direction opposite the first direction for decreasing the seal to allow the rotary valve member to be operated between the open and closed positions.</p> |
