US Patent 7681928 Pipe fitting

A pipe fitting is made of plastic, such as polysulphone PSU or polyphenylsulphone PPSU. At least one end of the pipe fitting (1) comprises an external thread (2) for connecting the pipe fitting (1) to a mounting element, such as a pipe or a mounting piece, e.g. a tap. The thread (2) comprises a ridge (3). Between the ridges (3) there is a continuous helical groove (4). On the bottom of the groove (4) between the ridges (3) of the thread (2) there are protrusions (5).