"Carbonized wood" gluing properties and surface finishing, good performance, and pine in the heat treatment process, turpentine basically volatile resin has cured, therefore, the resin ducts and Setsuko surface, do not do special sealing process can be directly do finishes. Carbonized wood outdoor chairs in use, it will not happen hot weather resin overflow, destroying the paint surface problems.
Kiln and tank "carbonized wood" outdoor chair production process are divided into primary drying and secondary drying, charring rapid heating, cooling and conditioning treatment, and then cooling the kiln (tank) 5 phase.
1 Primary Drying
From birth (wet) wood dried to approximately 12% (or 10%) moisture phase is called once dry. This stage can be in the kiln carbonization (tank) carried, also accomplished by conventional kiln. Given carbonization kiln (tank) of the cost is higher, and the high cost of equipment operation, so using conventional drying kiln for a more economical, and the drying quality is also easier to control, but the drying time.
(2) second drying
From 12% dried to a wood moisture content of 3% (or 4%) of the second drying phase is called. This phase carbonization furnace (tank) to complete. Moisture content of about 12% of the timber into the carbonization kiln, the first transition can be conventional drying. Dry bulb temperature from about 65-75 ℃ Start, and then heated in stages to about 125 ℃, wet bulb temperature gradually expanded to 25 ℃. Subject wood moisture content to about 3%, the secondary drying stage ends. This phase of the length of time, depending on the wood species and thickness, 22mm thick timber normally takes more than 10 hours.
3 rapid heating carbonization
Wood moisture content of 3% after, they spent the dry dangerous period. Can quickly heat up, in a relatively short period of time, rising carbonization temperature (usually 180 ~ 212 ℃). Carbonization temperature then held constant for about 3 hours, high temperature heat treatment of wood, the wood of the hemicellulose and amorphous cellulose degradation, wood moisture greatly reduce the number of hydroxyl groups. Meanwhile in wood extractives such as resin, terpenoids, tannins, acids, a large number of objects containing volatile. Thus greatly reduced hygroscopicity of wood, dimensional stability and significantly improved corrosion resistance. This stage, the kiln (tank) to be filled within a protective gas (usually water vapor), oxygen gas must be less than 2%, a simple measure of the kiln to maintain the wet-bulb temperature of 99.5 ~ 100 ℃.Otherwise, there will be very dry wood fire hazard, and the wood under high temperature oxidation, its strength is also unfavorable.
4 cooling humidity
Wood carbonization treatment, not only the water content is very low (0.5%), and the wood itself, the temperature is high, close to 180 ~ 212 ℃. Then the humidity can not be directly processed must first timber to cool. Note do not use air cooling, if the kiln outside in the fresh air flow into the kiln, it is easy to make wood fire. The correct way is to stop the radiator heating while spraying atomized water to the kiln, not only play a role in cooling, but also make almost all dry timber proper humidification.Subject to the kiln medium temperature dropped about 116 ℃, humidity conditioning treatment can be carried out. Then the kiln while the saturated water vapor injection, and then atomized water spray in order to enhance the relative humidity of the kiln medium moisture content of wood, and to eliminate the residual stress. Wood moisture content generally be increased from 4 to 5%, to end the humidity treatment.
Add: hunan province changsha city