What are the world's wood drying equipment and methods?

- May 08, 2019 -

< P > Wood consumption is very large in our country, which is usually used in furniture industry. The traditional way of drying can't keep pace with the times, so what are the ways of drying wood? Henan experts will elaborate on the drying method of wood < STRONG > drying equipment for you. The < P > drying method

< P > drying principle

< P > characteristics

< P > conventional drying

< P > conventional drying with furnace gas as heat medium occupies a considerable proportion in small and medium-sized wood factories in non-heating areas of southern China. Because it can treat wood waste in factories and reduce drying costs, it is welcomed by some factories with little drying capacity.

Conventional drying with hot water as heat medium, because the price of hot water boilers is much lower than that of steam boilers, there is an upward trend in some factories that do not need high temperature drying and have a small amount of drying. Conventional drying with hot oil as heat medium has relatively little application at home and abroad. The difference between high temperature drying

and conventional drying is that the temperature of drying medium is above 100 (?) C, generally 120 (?) 140 (?). The drying medium can be wet air or atmospheric pressure and high pressure superheated steam. The advantages of high temperature drying are fast drying speed, good dimensional stability and short drying cycle. However, high temperature drying is prone to produce drying defects, darkening of wood color, hardening of surface and difficult to process.

Solar drying

Heating air by solar radiation and circulating hot air between collector and stack to dry wood. Solar energy is a clean and cheap energy, but it is a intermittent energy which is greatly affected by climate. It has a long drying cycle and a large investment per unit volume, so the promotion of solar energy is limited. In order to shorten the drying cycle, solar drying is usually combined with other energy sources such as steam, furnace gas and heat pump.

P>STRONG>Microwave drying

microblogdrying equipment uses wet wood as dielectric and under the action of alternating electromagnetic field to make polar molecules in wood move in polar orientation and heat up by collision or friction between molecules, so that wood can be heated and dried from inside to outside at the same time. Advantages of

: fast drying speed, high efficiency, energy saving and environmental protection, uniform temperature field in wood, small residual stress and good drying quality;

Disadvantage: large investment, at the same time, if the power choice is different, excessive power or improper drying process control, easy to crack and carbonization.

Vacuum drying

Vacuum drying

Vacuum drying increases the water vapor pressure difference inside and outside the wood, which accelerates the water migration speed inside the wood. At the same time, due to the low boiling point of water under vacuum, it can achieve a higher drying rate at a lower temperature and has good drying quality, especially for hard hardwood with good air permeability or easy shrinkage and larger thickness. Over the past decade, vacuum superheated steam drying has been applied in Denmark, Germany, France, Canada, Japan and other countries with good results. However, vacuum drying equipment has high investment, high power consumption, and the capacity of vacuum drying is generally relatively small. At present, vacuum drying is seldom used in China. Under the irradiation of far-infrared rays, water molecules in wood absorb the radiation energy of far-infrared rays, which makes water molecules resonate, thus transforming electromagnetic energy into heat energy to heat wood, so as to achieve the purpose of drying wood. Advantages:

Simple equipment, easy adjustment of drying benchmark; Disadvantages: large power consumption, high drying cost, limited depth of infrared penetration of wood, uneven drying, easy to produce drying defects, and easy to cause fire, etc., currently rarely used. Pressure drying

is to place wood in a closed drying container, on the one hand, to raise the temperature of wood, on the other hand, to increase the pressure in the container, so that the moisture in the wood begins to vaporize and evaporate at a higher temperature, so as to achieve the purpose of drying wood

with good drying quality and shorter drying period, but with larger energy consumption, smaller volume of the container and smaller production capacity. In addition, the color of finished wood becomes darker after pressure drying, and there will be larger cracks around knots. The equipment corrosion, drying process and drying benchmark of this drying method need further study. Solvent drying

Solvent drying

Solvent drying

Solvent drying

Solvent drying

Solvent is to put wet wood in water-repellent solvent, raise the temperature of solvent, heat wood, vaporize and evaporate water in wood

Solvent is characterized by not absorbing moisture in wood, nor increasing humidity of wood, faster drying speed, simple equipment, easy construction and easy operation of technology, but mechanical strength of wood after drying has been improved. The reduction is not conducive to gluing and finishing. The commonly used water-repellent solvents are: paraffin oil, sulfur and so on.

Looking at the above icons, there are many drying methods for wood. Microwave drying is a popular drying method in recent years. Because of its high drying efficiency, energy saving, environmental protection and other characteristics, it is quickly accepted by the market. Henan Microwave Equipment Co., Ltd. specializes in microwave field and tailors < STRONG > dryer and < STRONG > drying equipment for the majority of enterprises. Welcome the leaders of enterprises to visit.

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