| 摘要 |
<p>A ball valve has a valve body and a ball shaped closure mounted on spindles which extend at right angles to the flow passage in the body. The spindle is sealed to the valve body by bellows-shaped, accordion-like or plaited sealing means dimesioned to with stand the pipe pressure in the valve, but nevertheless sufficiently flexible to permit tipping of the closure in response to pressure in the valve or to manipulation of the spindle from outside the valve about the spindle end situated on the opposite side of the closure. The tipping movement can occur when the pipe pressure acting on the closure is exceptionally high, and the closure can be turned from outside the valve from tipped position towards a position where the spindles are at right angles to the flow passage of the valve, so that the closure can be rotated at a lower torque to desired position.</p> |
