DRYING UNIT FOR WOOD CHIPPING PRODUCTS Russian patent published in 2014 - IPC F26B23/02 

FIELD: heating, drying.

SUBSTANCE: invention relates to a drying unit for wood chipping products, namely for wood chips or wood fibre, which contains a boiler (12) for combustion, which includes a device (14) for combustion of wood waste and an additional furnace (16), a flue gas pipeline (22) for discharge of flue gas (20) formed at combustion and a drier for wood chipping products, which is fed from the flue gas pipeline (22); with that, between the boiler (12) for combustion and the drier there located is at least one combination radiant-convective part (24) serving for heating of thermal oil passing through it; with that, the combination radiant-convective part (24) is equipped with a radial internal rising duct (26) and a downtake duct (32) enclosing the rising duct (26) in a radial direction. According to the invention, between the combustion boiler (12) and the combination radiant-convective part (24) there located is a radiant part; flue gas flows in the radiant part in a downward direction; the combination radiant-convective part (24) is made so that a rate (v) of the flue gas flow (20) before entry to the combination radiant-convective part (24) is over 22 m/s, the combination radiant-convective part (24) is made so that a rate (v) of the flue gas flow (20) in the downtake duct (32) is less than 19 m/s so that effective ash collection is possible; the combination radiant-convective part (24) operates as an ash collector and is equipped with an automatic ash removal device, and at least one combination radiant-convective part (24) is made so that flue gas (20) flows first vertically in an upward direction, and then, vertically in a downward direction; with that, flue gas (20) is cooled, and thermal oil is heated, and then, it passes through the convective part so that flue gas (20) continues to be cooled down, and thermal oil continues to be heated, and then, flue gas (20) is directed to the drier.

EFFECT: invention proposes a drying unit for wood chipping products, which provides for a possibility of continuous operation at combustion, and namely, wood fibre with high moisture content at reduced maintenance costs.

11 cl, 4 dwg