Wood Drying Kilns Just For You Special Drying Needs
This invention relates to wood dry kilns for drying lumber and other wood products
, and more particularly to a novel sticker by which wood products are spaced apart vertically in a dry kiln for the circulation of heated air. A "sticker" is a generic term for a spacer employed to separate layers of lumber in the kiln drying process. Its purpose is to allow hot air to flow uniformly between layers of lumber and allow moisture to escape from the wood. The rate of drying is critical and is controlled through the establishment of drying cycles which vary stepwise in temperature and time at each temperature. Drying cycles may very widely, depending upon the type of wood, with maximum temperatures ranging from around 160 F. for helmock to 260 F. or higher for southern pine.
This invention provides a wood dry kilns spacing sticker which is produced by the extrusion of a glass fiber-reinforced synthetic resin to form an elongated, hollow, internally reinforced sticker of light weight and high compressive strength. It is the principal objective of this invention to provide a sticker of the class described that overcomes the aforementioned limitations and disadvantages of prior stickers. Another objective of this invention is to provide a sticker of the classdescribed that retains its dimensional stability and integrity over a long service life.
It is a generally accepted practice to utilize wood drying kilns material for stickers. These range from clean Douglas fir to seasoned hardwoods, or end cuts of plywood and 16-ply laminated Douglas fir. The primary limitations and disadvantages associated with wood stickers are that they are subject to breakage and warpage and they take a heat set over uneven layers. Wood also embrittles after heat aging and it compresses and gets thinner over time. Knots in wood present weak points which result in premature breakage.