Mechanical face seals are used to seal an opening in the wall of a pressurized container through which a rotatable shaft extends. Many of these seal assemblies include a seal ring non-rotatably carried by a housing fixed to the container and a mating ring fixed to the shaft. The seal ring and mating ring are biased into rubbing engagement along confronting radial faces to maintain a pressure seal between the shaft and container wall.
In many of the above-described mechanical face seals, the seal housing which is fixed to the container at the opening is provided with lugs or pins which form anti-rotation abutments serving to prevent rotation of the seal ring with the mating ring on the shaft. In addition to serving as an anti-rotation means, these lugs or pins allow axial movement of the seal ring which is necessary to maintain sealing engagement with the mating ring. When lugs are used, they are welded in place in the housing. Pins are pressed into openings in the housing. It will be appreciated that the welded lugs and pressed pins can come loose and, if so, can destroy not only the seal itself but also the surrounding hardware. Furthermore, the welded lugs and pressed pins cannot be replaced easily upon wear and usually the entire seal assembly must be scrapped.