Pretreatment technology of atmospheric superheated steam for improving wood dimension stability

Abstract

The invention discloses a pretreatment technology of atmospheric superheated steam for improving wood dimension stability, comprising the step of finishing the pretreatment process through controlling numerical values of a wood inlet stack temperature, a wood outlet stack temperature and a wood core temperature as well as correlations thereof. Wood to be processed is placed in a pretreatment device, and sensors for measuring the wood inlet stack temperature, the wood outlet stack temperature and the wood core temperature respectively are arranged; not less than 2 detecting points are arranged in the wood inlet stack; not less than 4 detecting points are arranged in the wood outlet stack, half of the detecting points are used for detecting the wood outlet stack temperature, and the others are used for detecting the wood core temperature. After the hot steam treatment, the growth stress of the wood provided by the invention can be released, the plate surface is smooth and non-defective, the inner moisture channels of the wood are unimpeded, and the initial moisture content is obviously reduced. No chemical pollution is existent in the whole treatment process, the strength of the wood is not reduced, the air shrinkage and wet expandability of the wood are decreased, the dimension stability is obviously improved, and the wood textures are clearer. The wood treatment technology provided by the invention has the advantages of shortened preheating time, short treatment time and good evenness.

Description

technical field [0001] The patent of the invention relates to an atmospheric pressure superheated steam pretreatment process for improving the dimensional stability of wood. This process is mainly used for pretreatment before wood drying, especially suitable for improving the dimensional stability of fast-growing wood thick plates, and belongs to wood processing. technology field. Background technique [0002] Wood is mainly composed of cellulose, hemicellulose and lignin, and there are a large number of hydroxyl groups on the cellulose and hemicellulose molecules. When the moisture content of wood is lower than the fiber saturation point, due to the effect of hydroxyl groups, the wood evaporates or absorbs water with the change of external temperature and humidity, resulting in dry shrinkage or wet expansion, resulting in unstable dimensions of the wood and internal Stress, defects such as warping, deformation and cracking occur. In order to improve the dimensional stabil...

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Problems solved by technology

[0006] However, although the dimensional stability of the wood treated by chemical methods has been improved, because the wood contains chemical agents, the treated wood will pollute the environment and be harmful to the human body no matter when it is used or when it is disposed of as waste.

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