| 摘要 |
<p>A shut off valve for use with a concrete delivery hose includes a single flexible cylindrical sleeve disposed within a one piece, continuous rigid casing that surrounds the hose. A gas chamber is defined between the sleeve and the casing so that when pressurized gas is forced into the chamber, the sleeve will be displaced radially inwardly to constrict the hose and stop the flow of concrete. The shut-off valve also includes a relief valve for quickly exhausting gas from the valve, and an off/on indicator for indicating open/closed positions of the valve.</p> |
