Concrete hose shut-off valve

摘要

A shut off valve for use with a concrete delivery hose includes a pair of flexible cylindrical sleeves disposed within a rigid casing that surrounds the hose. A gas chamber is defined between the sleeves so that when pressurized gas is forced into the chamber the inner sleeve will be displaced radially inwardly to constrict the hose and stop the flow of concrete. <IMAGE> <IMAGE>