Our client is a sugar beet processor. The process of producing beet sugar ends with a beet pulp by-product that requires drying to increase its value as animal feed. The client installed a state of the art steam dryer with a rotary valve system to convey the pulp into the dryer and form an air lock to hold the pressure in the vessel. The Steam dryer OEM in Europe applies a Stellite overlay to the surface of these rotors, which are approximately 3 ft in diameter and 3 ft long. Without this Stellite overlay, the wear between the rotor and the shoe (brought about by erosion from the abrasive beet pulp and steam) would cause the rotor would fail, stopping production mid-stream during the 6 month processing campaign.
Deloro Stellite, through its Coating Services division in North America, was able to offer a turnkey refurbishment service on the rotary valves. This included a wear assessment of the part, adding stainless steel overlay to bring the base metal back to the original dimensions, and a final overlay of.090” of Stellite® 6 alloy powder applied using the PTA process, to minimize dilution of the alloy and provide the maximum wear resistance. The part was then stress relieved and machined to final dimensions. The capability of a local Deloro Stellite Coating Services facility allowed the customer to reduce the cost by 1/3 when compared with the expense of shipping this large part back to the OEM in Europe, or replacing the rotor every year with a new component, and reduced the downtime required for the refurbishment by several months.