Abstract: A method and device for inspecting the internal cross-sectional shape of pipes, and particularly of sewer pipes. A mandrel is inserted into the pipe. The mandrel may include an elastomeric member providing a fluid seal engaging the internal pipe surface. The mandrel also has a retrieval cord attached thereto and trailing therebehind. A plug member is provided behind the mandrel, which may be inflatably expanded to define a second fluid seal with the pipe. The space between the pipe and the two fluid seals is pressurized, such as with compressed air, causing the mandrel to advance along the pipe, pulling the retrieval cord as it advances. The mandrel's advancement will be stopped by a sufficiently large deformation. Thereafter, the mandrel is retrieved by pulling on the retrieval cord. In one specific embodiment of the device, a mandrel, including a flexible elastomeric member, is provided that is capable of ready modification to accommodate various diameter pipes.

Abstract: A method and device for inspecting the internal cross-sectional shape of pipes, and particularly of sewer pipes. A mandrel is inserted into the pipe. The mandrel may include an elastomeric member providing a fluid seal engaging the internal pipe surface. The mandrel also has a retrieval chord attached thereto and trailing therebehind. A plug member is provided behind the mandrel, which may be inflatably expanded to define a second fluid seal with the pipe. The space between the pipe and the two fluid seals is pressurized, such as with compressed air, causing the mandrel to advance along the pipe, pulling the retrieval chord as it advances. The mandrel's advancement will be stopped by a sufficiently large deformation. Thereafter, the mandrel is retrieved by pulling on the retrieval chord.