Tunnel fan manufacturers will introduce the reasons for the black smoke in the tunnel fan tidal tube. The tunnel fan is a long, straight channel with fixed kiln walls and roof on both sides and top (vault top). The kiln car runs on the bottom rail and is loaded.

The drying mechanism is: drying medium - the waste heat of the finished brick in the drying kiln, the drying medium is sent into the drying chamber through the fan, and the heat is transferred to the billet surface through heat exchange. After the surface of the billet is heated, the heat is transferred to the inside of the billet. Diffusion and conduction are heat transfer processes.

When the green surface is heated, the surface moisture evaporates and evaporates. The moisture inside the green body moves to the surface due to the moisture difference of the material, and then evaporates from the surface until the green body is dry, which is a heat transfer process. The heat source of the tunnel drying chamber, that is, the heat energy used for drying, is usually the hot air formed by the waste heat of bricks in the tunnel drying furnace, which is usually called furnace waste heat.