American Wood Dryers - Single Pass Continuous Dry Kiln
The Single Pass Continuous Dry Kiln (CDK) by American Wood Dryers introduces an advanced drying technology differing distinctly from the older counter flow design. This kiln allows lumber to enter from one end, moving through sequentially arranged sections for preheating, drying, and conditioning before exiting at the other end. This design integrates baffles on hinges to partition the sections, with springs to maintain tension. In the drying section, a heat source efficiently extracts moisture, while air circulation is facilitated using strategically positioned fans. The setup allows maintenance without needing shutdowns, as fan motors are accessed from the kiln's exterior. Lumber transportation is managed using carts driven by a hydraulic pusher system with incremental advancement controlled by a PLC, allowing precise control over drying speeds. This setup also features two tracks operating at different speeds to match varied moisture contents, while exhaust hoods help in dissipating moisture-laden air to enhance the drying process.American Wood Dryers offers a unique and patented type of Continuous Dry Kiln (CDK) referred to as a Single Pass™ . Compared to the older technology of the counter flow design where wood enters the kiln on opposite ends and on opposite tracks, the Single Pass kiln design allows all wood to enter at one end and discharge at the opposite.
Single Pass CDK advantages are:
- Improved Mill Flow with dedicated green and dry ends like batch kiln operations
- Reduced material handling labor and equipment costs
- Reduced drying energy cost
- Improved grade recovery
The Single Pass kiln is divided into three sections and partitioned by baffles mounted on hinges and tensioned with springs. The first section is a preheat chamber where wood is brought up to operating temperature. The second or center section is outfitted with a heat source and is where the actual drying takes place. The third and final section conditions the dry wood to equalize moisture content and relieve the drying stresses.
Air circulation fans are mounted along the entire length of the kiln. Fan motors are mounted on the kiln exterior to facilitate maintenance without shutting the kiln down.
Exhaust hoods are provided at each end of the kiln to disperse wet air and reduce water condensing and accumulating on the ground.
Lumber is transported through the kiln on carts. Carts are moved by a Pusher with a hydraulic cylinder and pawl arrangement located below and between the cart rails. The cylinder is fitted with a transducer and advances the load incrementally by the PLC control system. Speeds are typically in the 3’ to 8’ feet per hour range and adjusted depending on incoming and target moisture content. The 2 tracks can be operated a different speeds to accommodate different moisture profiles.
- Green Sawdust burners
- Dry Shavings burners
- Natural Gas burners
- Steam and thermal oil