The fourth type is the bell cover kiln.
Bell cover kiln is a kind of kiln wall, the kiln top constitutes a whole like a clock cover, and the movable intermittent kiln, so it is called a bell cover kiln. Its structure is basically the same as the traditional round inverted flame kiln. One or several layers of the nozzle are installed along the kiln wall. The installation position of each burner is the flame ejection direction and the circumference of the cross-section of the kiln. There are always two or several bell cover kilns, each of which is equipped with fire suction holes and a flue connected to the main flue. The structure of the kiln bottom is divided into kiln car type and fixed type. When the kiln car type bell cover kiln is used, the kiln cover is first raised to a certain height through the hydraulic equipment, and then push the kiln car carrying products into the kiln cover, lower the kiln cover, and the combination between the strict sand sealing kiln cover and the kiln car, and the kiln can start firing the kiln. When the fixed bottom bell cover kiln is used, the lifting equipment is used to lift the kiln cover to a fixed kiln bottom loading the good products, and seal the kiln cover and the bottom of the kiln can be burned. After the product is burned and cooled to a certain temperature, lift the kiln cover, push the kiln car, and push it into another kiln car loaded with the product, or lift the kiln cover to the bottom of another fixed kiln, and continue to burn another kiln product. Bell cover kiln is loading and unloading products outside the kiln, compared with the traditional inverted flame kiln, greatly improve labor conditions and reduce labor intensity. At the same time, like shuttle kiln, using high speed temperature control mouth to improve the heat transfer rate, shorten the firing time, improve product quality, save fuel consumption, especially using light high temperature resistant insulation material for kiln lining, not only reduce the kiln outward heat and heat storage, and greatly reduce the burden of kiln cover metal steel structure and lifting equipment, and can be like the shuttle kiln using program control system, realize automatic control of furnace heating stages.
There is also a bell cover kiln that can change the height of the kiln room. The kiln wall and the kiln top can be lifted separately by lifting equipment, and the kiln wall is built in separate circles, which can be flexibly installed and dismantled according to the height needs of the roasting products to change the height of the kiln room. Because the structure of the kiln wall is like a steamer, this kiln is also called a steamer kiln.