Abstract: The present invention comprises couplings which require no adhesives or cold welding or similar techniques for joining lengths of pipe of any known composition. The couplings, in their various shapes, are molded from Ultra High Molecular Weight Polyethylene (UHMWP). Within each end of each coupling form there are a plurality of spaced apart inwardly extending flexible rings, each ring terminating in an angular tip portion which is deformed in the direction of the inserted pipe end and forms a plurality of locking annular seals around the inserted pipe end portion. UHMWP has an inherent self-lubricity which facilitates the insertion of the pipe end portion. UHMWP is chemically inert.

Abstract: The present invention is a sewage clean-out line cover and removable cap made of Ultra High Molecular Weight Polyethylene. The interior of the cover carries a plurality of rows of upwardly inclined teeth, the rows being parallel and unconnectable to each other. The teeth comprising each row have a pitch to depth ratio of approximately 1:1. The ratio of the slope of the upper surface of the teeth to the lower surface is 1:1, thus providing a tip for installation over the open end of the upstanding clean-out pipe which tip is flexible for pushing the cover over the open end of the clean-out pipe due to the inherent lubricity of the UHMWPE but which resists removal of the cover by the tips folding over to increase friction against the clean-out pipe outer surface. The cover is usable with cast iron or PVC pipe or any other presently known material used to form sewage clean out pipes.