A sliding
pipe plug for working on and testing pipes is presented. The sliding
pipe plug includes a center portion and a
gasket disposed about the central portion. When towed through the
pipe, the sliding pipe plug maintains a substantial seal against water flowing through the pipe. In some embodiments, a flexible
gasket can be utilized to allow for substantial sealing while the sliding pipe plug is traversing obstacles in the pipe. The sliding pipe plug according to the present invention can be utilized in pipes where conventional plugs are inconvenient. For example, in FELL testing a
sewage line, a sliding pipe plug can be attached to a sonde cable and the testing can proceed without plugging and surcharging all of the section of pipe to be tested. In some embodiments, the sliding pipe plug includes a break-away section that allows the seal against water flowing through the pipe to be broken when the sliding pipe plug is pulled in a direction opposite the
towing direction. In some embodiments, the sliding pipe plug includes a centering section that keeps the sliding pipe plug essentially in the center of the pipe.