| 摘要 |
A hand-operated hemispherical or spherical valve that provides an improved seal when dealing with fluids containing, or consisting entirely of, particulate matter is provided by the present invention. The valve utilizes an inflatable elastomeric valve seat that interacts with a primary closing member to permit or restrain the flow of fluids or particulate matter in a channel. The valve is opened and closed by turning a handwheel that is connected to a drive shaft. A sleeve having a cam is mounted on the drive shaft such that the cam engages a pressurized gas supply switch that inflates the inflatable elastomeric valve seat or seats when the hand wheel is turned to a closed position. Conversely, when the hand wheel is turned to an open position, a valve drive shaft, key and keyway function in conjunction with the drive shaft to turn the sleeve and disengage the cam such that the elastomeric valve seats are deflated prior to the primary closing member moving out of the closed position.
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