Pipe coupling : this is a mechanical coupling consisting of a central sleeve, end flanges, and rubber gasket (wedge shaped). End flanges are tightened using high tensile bolts & nuts, keeping the rubber gaskets in between central sleeve & end flanges .this producers a leak-proof joint which is not rigid but flexible to the extent of 40 to 60. These couplings can be supplied to pipe lines of diameter varying from 12 to 28. (304.8 mm to 711.2 mm)cross-country domestic water pipe linethermal power plants for powdered coal piping .Nuclear power plants.Penstocks in hydel-power plant.Pollution control - effluent treatment plant.Oil field petrochemical piping.Chemical & fertilizer plants.Fly ash slurry line.Fire protection systems.