Difference Between Hoffman Kiln and Tunnel Kiln
 

Hoffman kiln is for semi- automatic line, and tunnel kiln is for fully automatic line. The difference between fully automatic and semi-automatic line is that the early cost of semi-automatic line is cheap, but  later the artificial cost is high and it's suitable for small capacity. On the contrary, cost of fully automatic line is  high, but the artificial fee is not cost, and it's suitable for large capacity.

Still, in spite of all that high-tech, they are not more energy-efficient than Hoffman kilns – both processes require around 2,000 kilojoules per kilogram of brick. If compared to some improved versions of Hoffman kilns, a tunnel kiln is even less efficient. Moreover, in modern brick production facilities all too often energy efficiency is sacrificed for speed and the drying and cooling processes are fastened by means of extra energy inputs.

In a Hofmann kiln the bricks stay where they are and the fire moves around, but in a tunnel kiln the fire remains stationary while the bricks move slowly through the tunnel. The fire is situated in the centre and the bricks slowly proceed through the tunnel on a train or a conveyor belt, so that bricks which are in the beginning of the tunnel are slowly being preheated by the fire further on, and bricks which have passed the fire are allowed to cool down gradually.

The reason for the existence of a tunnel kiln is that the production process is further accelerated, resulting in a much larger output of bricks. This might as well be the most devastating aspect of modern brick production, because there seems to be a correlation between the speed of production and the ease with which we demolish buildings.

Zhengtai Machiney Factory of Gongyi is specialized in the field of full set machinery of automatic brick making machine. After 20 years' development, our factory has a contingent of an advanced manufacturing technology, perfect detection means, and a complete quality assurance system according to the inferior soil, coal gangue, shale, fly ash and other waste residue.