dehumidification kiln drying schedules

Featuring lower cost drying at speeds equal to gas & steam, these kilns are continuously exceeding industry standards and changing the game. Extruded polystyrene foam (blue or pink rigid foam) in this thickness has an R value of 10. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. Our next kiln charge is scheduled to begin around February 6, 2023. The remaining width allows for a 36-wide door and space for your drying equipment. November 1, 2020. (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. Two-by-four material sawn from young trees, thinnings, and stem tops contains a significant proportion of juvenile wood and is particularly notorious for warp. Dehumidification: This kiln-drying process requires the use of a heat pump system to remove water from the wood. The T-bars are made from 1/2" galvanized pipe and are attached to the rafters with threaded pipe flanges. . Another common sticker size is 1" x 2", and these work fine as well. WOODWEB is a registered trademark of Woodweb.com. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). The last step requires a short period of high humidity to relieve the drying stresses in the boards. The column on the right I added part way through is the kiln's internal RH. A Checklist for Operators of Small Dry Kilns A companion to A Start-up Guide for Operators of Small Dry Kilns (FOR-132) Terry Conners, Forestry and Natural Resources If you cannot find exact match, look at SG of same family species. hb```[@9p(T-3jO:g)@S 4Y]g7l\V!c!$Bf J B@&xcEz8PH@ZHs1/X$qOq,x'x$0.rWg*d XAT10 );9 The velocity through the load is assumed to be between 275 and 350 fpm, except for the white woods (including maple, ash, basswood, hackberry) where higher velocities (up to 600 fpm) are desired and acceptable. /ColorSpace /DeviceGray A free BASIC program to convert the designations into actual temperatures and humidities is available from the author. In larger kilns, the heater may be needed in the latter part of the drying cycle. Created and Presented by: Henco Viljoen and Elijah McCarty with Nyle Dry Kilns. Although I can maintain the 90 degree temperature, I could not start at the recommended humidity level unless I added humidity. 0000002536 00000 n Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. The last thing to do before starting the kiln is to close the gable vent with an insulated cover. Share. building the dehumidification dry kiln. You could use the dehumidifier to dry wood but it would not be part of a "kiln." Just be a different process. The T-bars are made from 1/2 galvanized pipe and are attached to the rafters with threaded pipe flanges. With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). Hb```f``:A2,@!p"4|QP(y;ysc6f{f+&FfKi-L4+i`Vlf nwj2MM/E)rQ,^wm{'_B&%F`dbt JB*UWTmdIb& z P"f#*E4% @BHA!4I( I0 !`Hke0 PQI ([@R R`0 &xgTh( *p1 ~L{ endstream endobj 917 0 obj 389 endobj 908 0 obj << /Type /Page /Parent 892 0 R /Resources << /Font << /F0 909 0 R /F1 912 0 R >> /ProcSet 915 0 R >> /Contents 913 0 R /MediaBox [ 0 0 607 792 ] /CropBox [ 0 0 607 792 ] /Rotate 0 >> endobj 909 0 obj << /Type /Font /Subtype /TrueType /Name /F0 /BaseFont /CenturySchoolbook,Bold /FirstChar 31 /LastChar 255 /Widths [ 750 287 296 333 574 574 833 852 241 389 389 500 606 278 333 278 278 574 574 574 574 574 574 574 574 574 574 278 278 606 606 606 500 747 759 778 778 833 759 722 833 870 444 648 815 722 981 833 833 759 833 815 667 722 833 759 981 722 722 667 389 606 389 606 500 333 611 648 556 667 574 389 611 685 370 352 667 352 963 685 611 667 648 519 500 426 685 611 889 611 611 537 389 606 389 606 750 750 750 241 574 481 1000 500 500 333 1000 667 333 1000 750 750 750 750 241 241 481 481 606 500 1000 333 1000 500 333 907 750 750 722 287 296 574 574 606 722 606 500 333 747 367 500 606 333 747 500 400 549 344 344 333 576 747 278 333 344 367 500 861 861 861 500 759 759 759 759 759 759 981 778 759 759 759 759 444 444 444 444 833 833 833 833 833 833 833 650 833 833 833 833 833 722 759 611 611 611 611 611 611 611 870 556 574 574 574 574 370 370 370 370 611 685 611 611 611 611 611 549 611 685 685 685 685 611 667 611 ] /Encoding /WinAnsiEncoding /FontDescriptor 910 0 R >> endobj 910 0 obj << /Type /FontDescriptor /FontName /CenturySchoolbook,Bold /Flags 16418 /FontBBox [ -250 -215 1079 962 ] /MissingWidth 671 /StemV 149 /StemH 149 /ItalicAngle 0 /CapHeight 962 /XHeight 673 /Ascent 962 /Descent 215 /Leading 202 /MaxWidth 899 /AvgWidth 468 >> endobj 911 0 obj << /Type /FontDescriptor /FontName /CenturySchoolbook /Flags 34 /FontBBox [ -250 -220 1200 951 ] /MissingWidth 756 /StemV 84 /StemH 84 /ItalicAngle 0 /CapHeight 951 /XHeight 665 /Ascent 951 /Descent 220 /Leading 171 /MaxWidth 1000 /AvgWidth 463 >> endobj 912 0 obj << /Type /Font /Subtype /TrueType /FontDescriptor 911 0 R /BaseFont /CenturySchoolbook /FirstChar 31 /LastChar 255 /Widths [ 750 278 296 389 556 556 833 815 204 333 333 500 606 278 333 278 278 556 556 556 556 556 556 556 556 556 556 278 278 606 606 606 444 737 722 722 722 778 722 667 778 833 407 556 778 667 944 815 778 667 778 722 630 667 815 722 981 704 704 611 333 606 333 606 500 333 556 556 444 574 500 333 537 611 315 296 593 315 889 611 500 574 556 444 463 389 611 537 778 537 537 481 333 606 333 606 750 750 750 204 556 389 1000 500 500 333 1000 630 259 1000 750 750 750 750 204 204 389 389 606 556 1000 333 1000 463 259 833 750 750 704 287 296 556 556 606 704 606 500 333 737 334 426 606 333 737 500 400 549 333 333 333 576 606 278 333 333 300 426 833 833 833 444 722 722 722 722 722 722 1000 722 722 722 722 722 407 407 407 407 778 815 778 778 778 778 778 606 778 815 815 815 815 704 667 574 556 556 556 556 556 556 796 444 500 500 500 500 315 315 315 315 500 611 500 500 500 500 500 549 500 611 611 611 611 537 574 537 ] /Encoding /WinAnsiEncoding >> endobj 913 0 obj << /Filter /FlateDecode /Length 914 0 R >> stream You can achieve top-quality results with incredible efficiency. Place the sample board in the lumber stack in a location where it will dry at the same rate as the rest of the lumber in the dryer (see Figure C). If we revisit the example of a $1,300 gross savings from a load of 540 BF of white oak lumber, and we subtract the estimated cost of $62 to kiln dry the lumber, we arrive at a net savings of $1,238 less than retail. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. In the majority of cases, the drying schedules are from the world literature, with emphasis on U.S., Canadian, and British publications. Initially, I set the DH to 40% RH, because I dont want to remove moisture too quickly. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. A lock ( However, you may need more cycles depending on the species, moisture content, and size of the timber. For end baffles, I use 2-thick rigid foam insulation screwed to the main baffles. Kiln drying is usually preceded by air drying to bring the moisture content of the wood down below 30%. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. Schedules for several thicknesses and specialty products (e.g. This plan allows . The fact is, most of my stacks of lumber air dry to 15% moisture content before entering the kiln. Understand how kiln performance must be modified to permit the use of custom schedules for specific product applications; Be able to modify existing conventional kiln schedules to dry products in dehumidifier kilns; Recognize degrades common to various species, including hardwoods, and modify handling practices to minimize these The first charge of mixed air-dried 4/4 hardwoods and softwoods was kiln-dried from 18.4% to 7.3% moisture content (MC) in 15 days with no . Excel Program for Modeling Lumber Dry Kiln Operations - a model for lumber dry kiln operation. Sears Canada 70 Pint Dehumidifier. (Dry Kiln Operator's Manual. Do not know just how the end point of moisture would compare. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. Basically the idea seems to be to maintain a constant temperature, and to keep lowering the humidistat to maintain the SDR until the moisture content gets to the desired level. Website Content Copyright 2023 Nyle Systems |. Using a Kiln Schedule The order was 540 board feet (BF) of 5/4 white oak. -. /Name /ImagePart_0 This can be done by heating above 133F for 4 hours (measured at the core of the wood), or at 120F for about 7 - 10 days. The stickers are uniform in size and usually 3/4" or 1" square. The starter blocks should be as long as the stack is wide. HT systems use 40-60% less energy than gas-fired or steam dry kilns. Dehumidification kilns are similar to other kilns in basic construction and drying times are usually comparable. Anyway, I included my log of a load I did in Nov '06 for everyone's amusement. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. H6`2}s=n:l)CR>/"\ USDA, 1991) . Take a moisture reading in the end grain with a pin-type moisture meter or remote probe.) 301 0 obj <>stream A dehumidification kiln continuously recycles the heat throughout the chamber, rather than . 44. Without baffles, the top layers of lumber experience "potato chipping" with cupping, twisting or warping. A typical kiln schedule is a series of temperatures and relative humidities, which are applied at various stages of drying as can be seen in Table 1. . 158 p. Dry kiln schedules for commercial woods : temperate and tropical. Sorry, preview is currently unavailable. Operates at a temperature range from 80F - 160F (26 - 71C). Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. Basically, you dont want all of the air rushing out under the stack, so find a way to redirect it. Dehumidifier suggestion: http://amzn.to/2iYZqVZThis is the first in a series of videos showing how I built a kiln for drying lumber. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. The schedule designations use the popular U.S. Forest Products Laboratory designations. I then manually rotate the fan boxes halfway through the drying cycle. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. If required, look-up and write down the RH (sixth column) and EMC (seventh column) for each schedule step.

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