Preparation of drying process

The drying process of periodic forced circulation wood drying chamber includes: preparation, control of drying standard, completion of drying and storage of dry wood.
The preparatory work before drying includes the inspection of drying equipment, the establishment or selection of drying standards, the determination of medium moisture content and drying quality indexes, the sawn inspection board and test board and the testing of its moisture content, the piling of wood or wood cart into the drying chamber, etc.
Inspection of equipment: in addition to regular inspection of the drying equipment, before each drying operation, the drying equipment must be checked again, such as changing the gauze cloth for the wet bulb thermometer, changing the balance moisture content test piece, lubricating oil injection, etc., to ensure that the drying equipment is in a trouble-free state.
Establish or select drying standards: select or establish drying standards according to the species, specifications, drying quality requirements and drying equipment performance of the dried wood.
Determine final moisture content and drying quality indexes: determine final moisture content and drying quality indexes according to customer or production requirements. Generally, the final moisture content of dried sawn timber is determined according to the equilibrium moisture content of the wood area. At the same time, the use of sawn timber should be referred to. In general, the final moisture content of dried sawn timber is 2%-3% lower than the equilibrium moisture content of sawn timber corresponding to the local average relative humidity, and the final moisture content of dried sawn timber can be lower if it is used indoors.
Sawn inspection board and test board, test its moisture content: each dry must have a test board, but can not have a test board.
The following precautions should be paid attention to when entering the drying room:
(1 )The same drying chamber by dry wood must be the same species or wood similar, the thickness is the same, the initial moisture content is basically the same.
(2) When loading materials should be careful, do not touch the door, wall and indoor equipment, piled up or stacked to be stable and tidy.
(3) the windward side must be filled with wood, leaving no gaps. That is to say, for the orbital drying chamber, the air flow passes through the pile laterally and must be filled along the direction of the length and height of the drying chamber. For a forklift loading and unloading drying chamber, the air flow through the stack longitudinally must be filled in the direction of the width of the drying chamber and (or the length of the stack) and the height. If the material pile is not enough to fill a room, you can reduce the width of the total material pile (or reduce the number of columns), but the total length and height of the material pile, or the number of nodes and stack of each column of material pile can not be reduced, so as to avoid leaving a gap, short-circuit air flow, resulting in uneven drying, and has produced a drying defect.
(4) the same column heap of the material heap as close as possible, without leaving a gap, adjacent to the column pile, the position slightly staggered before and after, so as to avoid the pile end to end connected or the end of the gap is difficult to avoid through each other.
(5) Pay attention to the pressurized weight on the top of the pile.
(6) Put the moisture content of the test board and stress test board. If electrical moisture content measurement method is adopted, moisture content measurement points should be no less than three, and evenly arranged in different positions in the material pile, and finally the connecting wire is inserted into the corresponding socket installed on the chamber wall. If using the test board weighing method, should measure the moisture content of the test board initial moisture content, initial weight, and calculate the total dry weight of the test board, the test board end coated with waterproof paint, by the test window or inspection door into the material pile, and to prevent condensation water drops.
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