Image Number 2 for United States Patent #4607664.
A plug to be temporarily located in a blocking manner within a pipe of a sewage pipe system of a building. The plug is to be installed within the pipe system as it is constructed. The plug is mounted within a flexible, enclosing wall, sleeve. The plug is constructed to be frangible and totally dissolvable within water. A clamping device is mounted exteriorly on the sleeve directly in the area of the plug. When the plug is no longer needed, the clamping device is operated to effect breaking of the plug and then disposing of the plug through the pipe system.