| 摘要 |
A plug for a sewer pipe has an inner sleeve with threaded opposite ends. A pair of longitudinally aligned outer sleeves having cylindrical outer surfaces and opposite end edges are slidably mounted on the inner sleeve. An inflatable tube is carried by the outer sleeves, the tube having inner and outer walls as well as end folds. Air valves are fitted to the end folds to admit pressurized air into an air chamber provided within the tube. The threaded opposite ends of the inner sleeve are each fitted with a collar which is engaged by an end closure provided with an inlet port and an outlet port. Removable stoppers normally close each inlet and outlet port. The plug can be inflated within an end of a sewer line to provide a positive leakproof seal against a head of water. Also two of the plugs can be connected together in an assembly which allows a sewer line to be pressure tested.
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