Finned Tube Heat Exchanger Steam Radiators for Drying Kilns

Finned Tube Heat Exchanger Radiators for Drying Kilns

   There are many drying media for wood, the more widely used is wet air, followed by superheated steam and furnace gas. Drying kiln radiator is to use the heat in steam or hot water to heat the air, transfer the heat energy to the wood, and at the same time take away the moisture in the wood. Drying kiln radiators can meet the different temperature requirements of the three stages of wood drying.

(1) Preheating stage (A-B). When drying sawn timber, the first thing to do is to preheat the sawn timber, the purpose is to raise the temperature of the timber so that it can be uniformly heated through, soften the timber, eliminate stress, open up the moisture pathway, so that the gradient of the moisture content and the direction of the temperature gradient is the same. Its characteristic is to make the wood uniform heat through, not evaporation of water, but can be a small amount of moisture absorption, preheating the time required according to the thickness of the wood and tree species and different.

(2) Isokinetic drying stage (B-C section) This stage is mainly free water drying process. In the equal speed drying stage, by the wood surface evaporation of free water, the surface of the water content to maintain close to the level of the saturation point of the fibre, at this time there is a sufficient amount of free water for the surface evaporation, drying speed is fixed. As long as the temperature, humidity and circulation rate of the medium remain constant, the rate of reduction of moisture content also remains constant. In the equal speed drying stage, the higher the air temperature, the lower the humidity, the free water evaporation is more intense.

(3) Decelerated drying stage; in the decelerated drying stage, the moisture content of the surface layer is lower than the saturation point of the fibre, the amount of water moving from the inner layer to the surface is less than the evaporation intensity of the surface, the drying speed is gradually slowed down, and it is close to zero at the end of the drying process to reach the equilibrium moisture content. Therefore, the drying stage below the fibre saturation point is called deceleration drying stage.

 We produce wood drying kiln radiators, but do not undertake turnkey projects for wood drying kilns. Drying kiln radiator plays a vital role in the whole drying process, the temperature and humidity control in different stages will seriously affect the yield and drying cycle.