Data was collected from eleven foundries using the RIVS to line furnaces of 9 tons or larger capacities, melting grey, ductile iron or copper. Ten lined furnaces with silica, one foundry melted copper and lined with alumina-based refractory. Consistent and sustained improvements in operation and health and safety conditions were shown by all foundries using the advanced technology. All participants were using the full system. The study period ended in 2001. A summary of the principal results and benefits is detailed below.
- Air Samples for Respirable Silica – produced results between <0.01 and 0.02 mg/m3 when lining with the RIVS; four to ten times below OSHA’s (Occupational Safety and Health Administration) permissible exposure levels.
- Densities of linings – every foundry added more material than when manually lining a furnace, producing a denser lining. Only 5 of 11 foundries measured the densities of manually installed and RIVS installed linings. The densities of the conventionally produced linings ranged between 124 and 130 pounds/cu. ft. while those produced by the RIVS measured the maximum for silica between 137 and 139 pounds/cu.ft.
- Longer lining life in every foundry using the system. Typically, furnaces lined manually (with silica) lasted between 3.5 and 5.5 weeks. The RIVS lined furnaces lasted on average 2 weeks longer. In one foundry lining life increased 100 percent (from 3.5 to 7 weeks) and at another 143 percent improvement above manually lined furnaces. The 30-ton furnace lined with alumina based refractory lasted 50 percent longer than when lined conventionally.
- Workforce Reduction – Two workers operate the RIVS system despite the size of the furnace. Foundries surveyed manually lined furnaces using between 5 and 8 workers, depending on the size of the furnaces. The RIVS reduced that number to two, for a reduction ranging between 57 and 83%. Hours of labour to line a furnace decreased on average by 74% and overall elapsed time decreased by approximately 37%.
- Tonnage Throughput – All foundries reported a higher tonnage throughput per campaign simply because linings lasted longer. Increases ranged between 28 and 67 percent longer than when furnaces were conventionally lined.
- Fewer Annual Linings – Foundries reported an average 42% fewer linings annually using the system. Considering the cost of tear-out, relining and sintering each furnace, return on investment was significant.
Further Developments of the Refractory Installation and Vibration System
In 2008, Gradmatic turned its attention to providing the same technology for furnaces smaller than 9 ton capacity. Today, we can manufacture for furnaces with a form diameter as small as 20 inches or approximately 2 ton capacity. A a one ton furnace machine is currently in the development stage. The principles of superior deaeration and consistent even distribution of material applied to larger furnaces has been maintained for smaller furnaces. Foundries continue to report improvements compared to conventional lining methods.