Thermal modifying method suitable for logs or thick lumbers

A technology of thermal modification and log, applied in the field of thermal modification of logs or thick square timber, can solve the problems of the decline of mechanical properties of heat-treated wood, overcome the significant decline in mechanical properties, prevent moisture absorption and penetration, and broaden the scope of application Effect

Active Publication Date: 2016-10-12
HENAN IINKHIGH OVERALL FURNITURE CO LTD
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AI Technical Summary

Problems solved by technology

[0004] However, the degradation of carbohydrates also leads to the decline of the main mechanical properties of heat-treated wood, among which the impact toughness and flexural strength are most obviously affected by heat treatment, and the decline can reach nearly 50%, which limits the application of traditional heat-treated wood to Non-structural materials or products with small loads

Method used

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  • Thermal modifying method suitable for logs or thick lumbers

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The thermal modification method of the wood of the present embodiment, concrete steps are:

[0028] (1) Preparation stage: put the wood with a moisture content of 7~8% into the processing kiln;

[0029] (2) Heat treatment: Introduce nitrogen gas into the treatment kiln, raise the temperature in the kiln to 80°C within 1 hour, then raise the temperature from 80°C to 145°C at a rate of 15°C / h, and then from 145°C to 25°C / h The temperature is raised to 170°C at a rate of h;

[0030] (3) Cooling down: Turn off the heat source, lower the temperature in the kiln at a rate of 35°C / h, discharge the nitrogen in the kiln out of the kiln, and at the same time pass in nitrogen at normal temperature into the kiln, after the temperature in the kiln drops to 100°C, Air is introduced into the kiln, and water is sprayed into the kiln at the same time.

Embodiment 2

[0032] The thermal modification method of the wood of the present embodiment, concrete steps are:

[0033] (1) Preparation stage: put the wood with a moisture content of 7~8% into the processing kiln;

[0034] (2) Heat treatment: Introduce nitrogen gas into the treatment kiln, raise the temperature in the kiln to 90°C within 1 hour, then raise the temperature from 90°C to 150°C at a rate of 13°C / h, and then from 150°C to 23°C / h The temperature is raised to 160°C at a rate of h;

[0035] (3) Cooling down: Turn off the heat source, lower the temperature in the kiln at a rate of 30°C / h, discharge the nitrogen in the kiln out of the kiln, and at the same time pass in normal temperature nitrogen into the kiln, after the temperature in the kiln drops to 100°C, Air is introduced into the kiln, and water is sprayed into the kiln at the same time.

Embodiment 3

[0037] The thermal modification method of the wood of the present embodiment, concrete steps are:

[0038] (1) Preparation stage: put Douglas fir wood with a moisture content of 7-8% into the processing kiln;

[0039] (2) Heat treatment: Introduce nitrogen gas into the treatment kiln, raise the temperature in the kiln to 100°C within 1 hour, then raise the temperature from 100°C to 140°C at a rate of 10°C / h, and then from 140°C to 20°C / h The temperature is raised to 180°C at a rate of h;

[0040] (3) Cooling down: Turn off the heat source, lower the temperature in the kiln at a rate of 40°C / h, discharge the nitrogen in the kiln to the outside of the kiln within 10 minutes, and at the same time pass nitrogen at room temperature into the kiln, and then the temperature in the kiln will drop to 100°C , into the kiln air, spray water into the kiln at the same time.

[0041] For verifying the effect of heat treatment method of the present invention, choose a long 79cm in the heat ...

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Abstract

The invention provides a thermal modifying method suitable for logs or thick lumbers. The method comprises the following wood treatment steps: woods with a water content of 7-8% are put in a treatment kiln; nitrogen is filled in the treatment kiln; the temperature in the kiln rises to 100 DEG C within 1 hour, rises to 140-150 DEG C at a speed of 10-15 DEG C / h, and rises to 160-180 DEG C at a speed of 20-25 DEG C / h; a heat source is closed; the nitrogen in the kiln is discharged out of the kiln; meanwhile, normal-temperature nitrogen is filled in the kiln, so that the temperature in the kiln is reduced at a speed of 30-40 DEG C / h; after the temperature in the kiln is reduced to 100 DEG C, air is introduced in the kiln; and meanwhile, atomized water is sprayed into the kiln. The heat treatment is performed under normal-pressure drying condition, so that the operation is safe, the treatment environment is not corroded, the treatment period is obviously shortened, and the production efficiency is high; and the treated woods have double-layer structures, so that the surface layer stability and durability are improved, the internal wood chemical structures are not changed, and the total wood mechanical strength is kept basically invariable.

Description

technical field [0001] The invention belongs to the field of wood modification, and in particular relates to a thermal modification method suitable for logs or thick square materials. Background technique [0002] Wood heat modification, also known as wood heat treatment, is a method of heat treatment of wood in an inert environment around 200°C to adjust the color of wood and increase its dimensional stability and biological durability. The inert treatment environment is used to avoid excessive degradation of wood in an aerobic high-temperature environment and to avoid fire hazards. Commonly used inert media include water vapor, nitrogen, vegetable oil, and water. [0003] The increase in dimensional stability of heat-treated wood was mainly attributed to the partial degradation of carbohydrates in wood, especially hemicellulose, at high temperature. Existing studies have shown that 160°C is a temperature turning point for wood heat treatment. When the temperature level is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B27K5/00
CPCB27K5/0085
Inventor 丁涛耿君蔡家斌彭文文胡新军
Owner HENAN IINKHIGH OVERALL FURNITURE CO LTD
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