Drying process of wood drying machine

Wood drying machine of the drying process is divided into six stages, respectively is low temperature preheating, early treatment, intermediate processing, balance, final processing and surface drying stage.
First, low temperature preheating: first the boiler steam pressure reaches 0.35 0.4 Mpa ready supply;Open the controller to start the fan, open the heating valve manually, moisture removal and steam injection is in the closed position, open the manual water drain valve at the same time, let the steam into the radiator can get a good cycle, after the row after the return of condensate auxiliary drain valve closed, the main water valve don’t close;Reverse a fan intervals of two hours, reversal process stroke opportunity stops for 3 to 5 minutes to start the fan, if there is any abnormal situation since the start should immediately stop operation for maintenance, troubleshooting is started after operation;Kiln, then on the basis of the original temperature rise in 2 to 3 degrees per hour, rising to preheat start points 35 to 40 degrees, after arrive 35 to 40, keep the corresponding time with automatic heating, and then to the next link;Staff in operation should be clear, be familiar with operation steps, every two hours to record one controller on temperature and humidity of actual values and the steam pressure, air blower for automatic, in turn, reverse once every 2 hours, to be recorded.
Second, the initial processing: preheating temperature humidity setting in the benchmark values only, manual steam injection is opened, the humidity rise speed per hour 3 degrees Celsius rise, basic value has been achieved initial steam injection;Steam injection after reaching the benchmark, with automatic steam injection to keep the existing humidity response time, hold time keep every centimeters plank according to 2 to 3 hours (such as: 30 mm thick plate processing per cm 2 hours early to keep words, is to keep 6 hours, 3 hours per cm stay, that is 9 hours).Early treatment plate must be sprayed, lay the foundation for drying the next stage, with automatic after steam injection to keep, turn into normal dry, start cooling temperature drop per hour or so;After cooling to the dry benchmarks for open the automatic heating valve according to the benchmark is dry, normal operation of basic value to dry the back wave don’t have to shut down, the base plate the change of moisture content of the appropriate temperature, moisture content test board at any time, processed early.
Three, intermediate processing: close the heating valve and moisture removal, open the manual valve of steam injection, the humidity is set in the middle processing benchmark, began to gush steam heat up about 3 degrees per hour, steam injection at a predetermined time benchmark, if do not have the steam injection can extend the steam injection time according to actual situation.(such as: power failure or in the process of steam injection pressure reach steam injection, steam injection to the requirement of pressure is not less than 0.4 Mpa).Steam injection after reaching middle processing benchmark, open the automatic steam injection to keep the existing humidity corresponding time, keep after cooled, cooling speed per hour down 2 to 3 degrees, to the benchmark after processed into normal dry middle stage;To dry after open the heating valve benchmark to remain the corresponding number of days, according to the change of lumber moisture content of the appropriate temperature, the change of test plate moisture content at any time.
Four, balance processing: according to the actual situation and decide, if can be omitted in the case of lumber moisture content is on average the moisture content of the link (balance) if the plate is not the average sheet (for example: the moisture content in 16% 14% 10% 16%) of the lumber moisture content of the average degree within five difference can not do balance processing, more than 5 and will need to do normal;Automatic heating valve closed, open the manual valve of steam injection, the humidity is set on the steam injection benchmark for steam injection, steam injection rate control in 3 degrees per hour, spray to the benchmark open automatically after steam injection to keep the existing humidity corresponding time sheet (steam injection rate per cm by 1.5 2 hours), keep cool down after, drop around 3 degrees per hour, with moisture removal control cooling speed, to open the automatic heating keep the corresponding number of days after drying at baseline, balance processed into dry stage.
Five, the final processing: close the automatic heating and moisture removal, humidity setting on the final value, humidity rise at the rate of 3 degrees per hour, after reaching final benchmark with automatic steam injection to keep time.Automatic steam injection after cooled, cooling speed per hour for 3 degrees, has been to the final dry benchmark, into a surface drying.
Six, surface drying stages: surface drying stage, set the humidity in drying at baseline, 1 to 2 days began to dry, model test moisture content at any time during this period;Sheet such as the moisture content of qualified, shut off the heating moisture removal control began to cool, summer has dropped below 40 degrees doors out of kiln, winter has dropped below 30 out of the kiln.