Roller Hearth Kiln
A roller hearth kiln is a continuous operating kiln. It has a low profile and fast firing cycle. The kiln furniture mass is greatly reduced as the ceramic rollers carry the load through the kiln. It can be either natural gas or electric fired. Atmosphere other than air is not a wise application of this kiln. The kiln is fully closed except for the entrance and exit end tables. A line (roll top) of ceramic rollers convey the ware on a setter plate through the kiln. One side of the rollers is the drive side and the other is the idler side. An AC motor and speed control adjustments the inch per minute travel speed of the kiln drive. The roller hearth kiln is known for it economy of operation, uniformity, rapid firing cycles and ease of maintenance. The operating temperature design can be as high as 3000F. A fiber-lined design will operate to 2500F.
Mesh Belt Furnace
The Mesh Belt Furnace is a continuous running furnace that uses an alloy belt of the flat weave or balance weave design. The belt is pulled through the furnace from the exit end drive. This drive can be either a flat drum for balance weave or a gear tooth drive for flat wire belt. The belt returns under the furnace to the entrance end. The rate of belt speed is controlled by an AC drive speed controller. The electric AC drive motor is connected tot he gear reducer and the drive output sprocket. The output sprocket is chain connected to the drive sprocket and belt drive drum to produce belt drive movement. Insulation of the furnace is a fiber module system for the floor, walls and removal modular roof assemblies. The heating system can be either electric heating elements or natural gas burners. The furnace is equipped with a New York Blower Co. exhaust fan mounted at the cooling exit end. The maximum operating temperature is 1650F with a 316 SS alloy. Other alloy belts can be rated to higher temperatures.
Car Shuttle Kiln
A car shuttle kiln has an open bottom that is enclosed when on or more kiln cars carrying the ware is in place. There is a door at each end of the kiln to load or unload the kiln with one set of tracks three times as long as the kiln. The operating principle of this kiln is to open one door push of the fired ware then close the door, open the other door an push in the green ware. This design can be used with natural gas or electric fired up to 3000F. The most common size ranges from 100 to 200 cubic feet of firing space.
The kiln design is also convertible from shuttle to a tunnel kiln. This allows for a less expensive periodic kiln for start up an lower production requirements. As your need increases, the kiln can be converted to a tunnel kiln by adding a pre heat section and a cooling section to the existing fire zone section. A full complement of kiln cars must be added to the length of the kiln.
Car Bottom Kiln
A car bottom type kiln incorporates the bottom of the kiln; the door is attached tot he kiln car and closes the entire load when the care is rolled forward. The design can be used with natural gas or electric fired up to 3000F. The most common size ranges from 100 to 200 cubic feed of firing space. This system can be set up to allow for future expansion of a second car with transfer tracks thus allowing one car to be in the kiln firing while the other car is being unloaded and reloaded with green ware.
The car bottom kiln is for periodic operation and offers flexibility with respect to firing cycles and schedules. This kiln can be placed on top of an existing floor and uses natural draft for kiln exhaust through the roof keeping installation costs to a minimum. Should it be necessary, this kiln system is very easy to relocate.
Tunnel Kiln
Although there are several types of tunnel kilns, the most common are the car tunnel kiln and pusher slab kiln both designed for continuous operations. The car tunnel kiln uses a train of kiln cars to close the bottom of the kiln. The ware is loaded onto each kiln care and then pushed into the kiln at the entrance end by the main kiln pusher simultaneously pushing a car out at the exit end of the kiln. Transfer cars and external return tracks can be manual operation or fully automatic. This design can be used with natural gas or electric fired to 3000F, the most common fuel being natural gas. Many systems can be incorporated on a car tunnel kiln such as pre heat an cooling re-circulation fans, quick cooling blowers, waste heat to dryer duct systems, pre heat and cooling exhaust and kiln pressure control.
The pusher slab tunnel kiln incorporates a ceramic heart plate system that conveys ware through the kiln on a ceramic pusher plate. Operating on the same principal as the car tunnel kiln, as one pusher plate is pushed in the kiln the continuous line pushes a pusher plate out at the exit end. A closed loop automated return system conveys the ware down a return line for unloading and loading. The pusher slab tunnel kiln offers atmosphere control with electric heating elements. This type of kiln is best suited for small technical ceramics an requires design for firing cycle, atmosphere and firing profile curve. For the mot part, the fas fired roller hearth kiln has replaced the gas fired pusher slab kiln since it is more efficient to operate.
Control System
Allied Kiln Service Inc. specifies the Kil-Tel Supervisory Control System for complete profiling, data acquisition, zone heating control and Pulse Fired combustion systems. (kiltelsystemsinc@kiltel.com)