Miller Mechanical Services, Inc. fabricates mechanical scraper assemblies for the bottom of digesters and impregnation vessels.  MMSI has fabricated scrapers out of carbon steel, carbon steel with Inconel overlay, stainless steel, Duplex 2205, and various combinations of all these materials.  Carbon steel scrapers can be stress relieved after welding.  Scraper arms can be solid plate or formed out of plate to be hollow to allow liquid flow through the arms.