The Ceramics Business Unit of Nutec Bickley has completed a major refurbishment project for Empire Comfort Systems, the Illinois-based business renowned for its White Mountain Hearth, American Hearth, Plaza and Montigo fireplace offerings. The requirement here was to as quickly as possible bring one of the company’s large gas-fired shuttle kilns back onstream – with the aim of completing everything within 10 weeks.
The contract involved the design, manufacture and supply of seven new kiln cars, restoration and relining of the kiln’s refractory bench and sand seal, as well as full replacement of the door insulation and sidewalls/roof seals. Nutec Bickley engineers took precise measurements onsite before finalising all design aspects, work that included completely stripping the old kiln cars of their insulation to locate sockets for the refractory posts for the new cars.
The kiln at Empire Comfort’s Poplar Bluff (Missouri, USA) manufacturing facility is now fully back in operation, primarily being used to fire the company’s Primo ceramic grills. This is a vitrification/sintering process in an oxidising atmosphere, with advanced high-velocity nozzle-mix burners firing above and below the load.
The new kiln cars were designed to use existing kiln furniture, and were fabricated using a lightweight but robust welded structural steel with eight single-flanged wheels arranged to run on a four-rail track. New trackwork was needed, and this was installed by Nutec Bickley as part of the contract.
A sand trough forms the kiln contact between the side of the kiln car and the side walls. The car blade (or skirt) is removable with bolts. When the cars are in position in the kiln, the end seals on the cars make a car seal built into the kiln door. The car insulation is a proven Nutec lightweight design. The perimeter of each car is formed using insulating firebrick while the interior is filled with low thermal mass ceramic fibre modules to form a clean and lightweight kiln car centre. The car chassis include a hooking/unhooking system to enable the existing transfer car to move the entire train of cars in the kiln.
For bench restoration, the existing refractory bench and sand seal were demolished and removed. The new sand trough has been fabricated in 409 stainless steel. The new side wall to kiln car seals are constructed using a combination of insulating brick grades with a double labyrinth seal to prevent heat loss and radiation leakage from the kiln chamber and the infiltration of cold air. A sand seal is incorporated to aid in this system.
The kiln doors were relined using Nutec’s proprietary high thermal efficiency ceramic fibre system for excellent insulation and long life coupled with low maintenance. The lining is rated for use up to 1,350 °C. The doors to walls/roof seals were also replaced on both ends of the kiln. The kiln walls were adapted with necessary burner sight hole tubes, thermocouple mounting tubes and chamber pressure port take-off.
The main photo shows the installation of the new Nutec fiber kiln door insulation.
