The working principle of the sawdust dryer is very simple. It adopts a downstream drying method. Before drying, pre-heat treatment should usually be carried out. The purpose is to heat the sawdust and increase the temperature of the core layer of sawdust. After the drying stage, it can accelerate the movement of internal moisture to the surface. This can reduce other problems in the drying process, ensure that the wood chips can be dried evenly, and preheating can also improve the drying efficiency and reduce the drying cost.

  The pre-heat treatment of the sawdust dryer can be carried out in two steps. First, increase the temperature of the medium to 40~45°C and maintain it for half an hour to 1 hour. Sawdust drying is a low-temperature conventional drying. Its preheating temperature should be 5°C higher than the temperature in the reference stage; the relative humidity can be controlled for drying. The wet bulb temperature difference is 1~3℃. When the new sawn timber or the initial moisture content is high, the dry and wet bulb temperature difference should be small, that is, the humidity is high; the equipment in the kiln and the kiln inner wall and the surface of the wood chips should be heated to avoid high temperature. Condensation water is generated on these surfaces during wet processing. Then pre-heat treatment is carried out, which mainly uses spray steaming, or a combination of spray steaming and heating, to raise the temperature and humidity to the required medium state at the same time, and keep it for a certain period of time to allow the wood chips to heat through. The preheating time should be such that the core temperature of the wood chips is not lower than the specified medium temperature of 3℃, which can be estimated according to the following empirical method. For each thickness of the material 1cm, the time should be maintained for 1.3~1.5 hours, and it can be extended by 50%~100% in winter. After the preheating, the temperature and humidity of the medium should be reduced to the specified values in the corresponding stage of the reference, that is, the drying stage will be entered.

  Practice has proved that reasonable pre-heat treatment is beneficial to guarantee the quality of sawdust drying (effectively avoiding the occurrence of mildew and blue staining of sawdust), semi-dry material or air-dried material, the difference between the dry and wet bulb temperature is too large, that is the humidity is low. The general principle is to preheat the vast majority of wood chips without drying or absorbing moisture. At the same time, it can reduce the generation of condensed water on the surface of the wood chips of the kiln during the humidification stage, thereby improving the drying efficiency, reducing the drying energy consumption per unit of wood chips, reducing drying costs, and improving benefits. Our company will guide customers to ensure that customers can dry out high-quality wood chips at a low cost.