Method for impregnation of wood by pressure surges during immersion
OwnerEwald Arvidssoninventor
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Abstract
Unit loads of wood, surrounded by a small quantity of liquid, are impregnated in sturdy vessels provided with a cover. After or during an impregnation period under vacuum, the impregnation is completed by subjecting the liquid and the wood to pressure surges or impacts of such an intensity that the wood is deformed in the direction of length of the fibers or in the radial or tangential direction thereof within a range between the average pressure causing breakdown of the wood material and one-third of that average pressure. Intensity of pressure surges increases as the vessels are filled with impregnation liquid. Pressure waves may be produced by means of either compressed air, steam or explosive gas. A connecting chamber is provided for preparation and storage of the impregnation liquid.
Claims12
A method for impregnation of wood in which wood immersed in an impregnation liquid is subjected to pressure steps starting with atmospheric pressure after vacuum treatment evacuating air from the wood cells, the impregnating liquid being absorbed by the wood upon an increase in pressure, characterized in that the wood immersed in said liquid is subjected to short increasing pressure surges of a duration substantially less than one second, the maximum intensity of said pressure surges being such that the wood is compressed to a pressure in the range from one third of the breakdown pressure of the wood to the breakdown pressure of the wood, each such pressure surge being followed by a recovery to equilibrium at substantially atmospheric pressure.
Dependencies are inferred from the claim text.