dehumidification kiln drying schedules

After two days operating only the fans and DH, I take note of the temperature. Measure airflow over the stacks of lumber in various locations. For a small scale shed kiln, I recommend a maximum footprint of 200 square feet. If the fans and dehumidifer generate enough heat to maintain a temperature of 100 to 120 F, then I won't use the auxiliary heater. Fundamental Aspects of Kiln Drying Lumber | Oklahoma State University I cannot stress the importance of baffles enough. Once the flooring deck is constructed, think about sealing the shed framing at every opportunity. I found that brackets for mounting rigid metal electrical conduit work best. Both restrained and control boards were dried to approximately 9 percent moisture content, representative of final in-service condi- tions. As the MC drops and I crank the DH on more and more, the temp tends to rise up too high just from the heat the DH throws off, even though the light bulb heaters are not on at that point. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. 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. . For these reasons, I feel it is best to let the shed breathe, and forgo a plastic vapor barrier. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. The company's small kilns can be configured for drying lumber, firewood, or heat-treating lumber or wood packaging. (I have found that remotely monitoring the temperature and humidity with a WiFi sensor can be very helpful. Without baffles, the top layers of lumber experience potato chipping with cupping, twisting or warping. I either use some cedar 3 x 5, or 4 x 4 stock. Moisture Content Dry Bulb Wet Bulb Depression percent degree F degree F degree F Above 50 110 106 4 50 to 40 110 105 5 40 to 35 110 102 8 35 to 30 110 96 14 30 to 25 120 90 30 Soon the DH won't show much water collected in the tray. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. This air space is absolutely critical for even airflow, so count on the extra floor space right from the design phase. organization in the United States. 0000001208 00000 n Saving money by drying your lumber may not be the answer for every woodworker, but the basics shown here demonstrate that it is within the reach and skills of the average person. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. Application of Heat Pump Dehumidification : A Case Study : Drying Typical dehumidification kiln (FPL 1999 p. 12-10). A kiln schedule is a set of temperatures and humidities that are used during kiln operation. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. The KD150 Dehumidification Kiln Kit is a compact, entry-level dehumidification kiln for drying lumber between 300 and 1000 board feet. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. The column on the right I added part way through is the kiln's internal RH. Fundamental Aspects of Kiln Drying Lumber - Academia.edu 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 A lock ( I then manually rotate the fan boxes halfway through the drying cycle. Ciencia y Tecnologia, Duygu Kocaefe, Ayhan Aytin, The Bolivian secondary forest products industry has experienced substantial growth during the last 10 years. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. The second temperature value is written for the 25 to 30% MC class; the third for the 20 to 25% MC class; and so on. Dehumidification: This kiln-drying process requires the use of a heat pump system to remove water from the wood. (A major source was Dry Kiln Schedules for Commercial Woods which is available from the Forest Products Society in Madison, WI.) Kiln drying is usually preceded by air drying to bring the moisture content of the wood down below 30%. Remove samples from the stack, and cut an inch or two off one end. Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. Formulating a Kiln Schedule End baffles are also a good idea to prevent airflow from bypassing the stack entirely. NYLE SYSTEMS L200 SERIES USER MANUAL Pdf Download For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. /Width 1628 Farm Forestry timbers - Drying (Seasoning) Timber HT systems use 40-60% less energy than gas-fired or steam dry kilns. 0000006274 00000 n (Sawing and Drying Forum) Sign In Upload. However, the natural light and ventilation offered by a small window outweighs any disadvantages. Kiln drying is almost always essential for wood intended for interior uses. There are two ways to remove water from the DH unit, and they both work well. For the best experience on our site, be sure to turn on Javascript in your browser. In the fourth column, write down the wet-bulb depressions (determined in #4 above), one for each Schedule Step, starting at the top (Schedule Step 1). If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. Changes in kiln temperatures and humidities are based on the MC of the lumber being dried, which in turn is determined from properly prepared kiln samples. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. _ Wikipedia Take a moisture reading in the end grain with a pin-type moisture meter or remote probe.) Unlike general shop space, bigger is not always better for kiln design. "Safe Drying Rate" and a Dehumidifier Kiln - WOODWEB A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. To accommodate the floor insulation, blocking between joists is oriented horizontally instead of the normal vertical position. 1. a furnace or oven for burning, baking, or drying, especially one for calcining lime or firing pottery. 158 p. Dry kiln schedules for commercial woods : temperate and tropical. Many regions have increased the shed and outbuilding maximum allowable size without need for a permit. 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. With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). Total costs for the materials were $2,704 based on 2006 prices. From contributor D: Such temperatures are high enough to kill insectsanother advantage of kiln drying over air drying. 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). The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. I usually see a large volume of water in the DH each night when I check the kiln. /ColorSpace /DeviceGray A heavy-duty 1,500-watt space heater works fine. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. The cost associated with shed construction was similar to buying a prefabricated kit. A small "m" after the designation indicates that the wet-bulb temperatures should be adjusted to avoid temperatures below 90 F. See the above mentioned publication for details. Leave an air space between the rigid foam and subfloor for additional insulating properties. Taking moisture away at the rate the board will "safely" part with it . Corrosion resistant epoxy coated aluminum cabinets and specially coated dehumidification coils for an extra long life. The kiln schedule information in the tables below has been assembled from many different sources, including drying texts and industrial contacts. Once the lumber is sterilized, it is ready for the conditioning phase. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. PDF FOR-131: A Checklist for Operators of Small Dry Kilns 6. This can create internal stress in the lumber that is released when sawing. Drying lumber too quickly can lead to deep end checking, warping and case hardening. Wood - Treatments | Britannica Align the stickers over the starter blocks on the first course. Subtract the wet-bulb depression from the dry-bulb temperatures for each schedule step and enter the value in the fifth column. I have been reading & studying kiln schedules for years too. Cost and operation of a Small dehumidification dry kiln - ResearchGate Design and Operate a Small-Scale Dehumidification Kiln The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. Q,kjifT33P[! A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. Dehumidification drying system. Conventional kiln drying. However, you may need more cycles depending on the species, moisture content, and size of the timber. A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. It is a meaningless exercise to try to convert those schedules for the kiln you built. 0000000591 00000 n hb```[@9p(T-3jO:g)@S 4Y]g7l\V!c!$Bf J B@&xcEz8PH@ZHs1/X$qOq,x'x$0.rWg*d XAT10 );9 Schedules. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. A locked padlock Bring your moisture meter to confirm. Dehumidification Kiln Packages - Nyle Systems - Lumber Drying Systems 4. The lumber was then measured for crook, bow, and twist. In-service replacement of warped 2 by 4's as wall studs or truss members is costly. I chose double wall construction with 1/2 sheathing, and 1/2 T1-11 siding. Be sure that all of the kiln equipment is working prop-erly before lumber is loaded into the kiln. This fact sheet summarizes the basics of kiln drying wood, the most commonly used methods, drying schedules and some drying defects. This will allow the DH to drain automatically without you needing to enter the kiln. Omitting the sterilization phase can lead to costly losses from insect damage, so dont skip it. Our next kiln charge is scheduled to begin around February 6, 2023. In Fig. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. Milling the stickers square is advantageous over a rectangular cross-section, because no matter how you place the stickers they will form a level stack. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. In a professional DH kiln, the final climate for oak is 120F and <40>t over-dry it at that rate. Nyle. A lazy Susan with 180 detents mounts the fan box to the ceiling. Our approach was to build and operate a small dehumidification dry kiln. 3.24 solar-dehumidification drying kiln A dry kiln needs to be operated when it is filled with lumber and forces airflow through the tiers of lumber instead of around the ends or over the top of the stack(s). In this system, moist air is not vented out of the kiln but is dehumidified, then recirculated . Fundamental Aspects of Kiln Drying Lumber - Oklahoma State University Kiln - Wikipedia The stickers are uniform in size and usually 3/4 or 1 square. Place a 1x6 board on the floor behind the stack, tilted to a 45 angle. Another reason I like the idea of a shed kiln is the flexibility of future use. This serves a dual purpose of supporting the rigid foam insulation as well as stiffening the floor framing. Seems like a pretty simple way to run the kiln - once or twice a day just measure the amount of water extracted, and turn down the humidity a bit as needed. If you intend to kiln dry lumber from a green state, right off the sawmill, you will need to be well-versed in airflow rates and follow a detailed drying schedule. Our approach was to build and operate a small dehumidification dry kiln. A dehumidification kiln makes sense particularly when the lumber is air-dried first. I am also curious why an initial temperature of 90F would have been selected. Website Content Copyright 2023 Nyle Systems |. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. There are two ways to remove water from the DH unit, and they both work well. - Model L300, L500, L1200-S Series - Medium Dehumidification Dry. There are many types of kilns, but the most common are dehumidification kilns and conventional kilns. If it isn't overheating, it is leaking. Additionally, I have been underwhelmed by the performance of solar-operated fans. So, with that lengthy introduction, here is my question. On this order alone, I saved over $1,300 by drying the lumber myself. My four main baffles consist of sheets of 1" Styrofoam insulation. I modified one of the Radio Shack combo units so it could measure the RH remotely as well as the temp. Go to the first number designation (the temperature designation) and find the corresponding temperatures in the table below. WOODWEB is a registered trademark of Woodweb.com. Dehumidification drying equipment is available, but an enclosure must be built to house the equipment and dry the lumber. At the planer mill, warped 2 by 4's represent a significant loss in value. Another great option is to convert an existing shed or outbuilding to a lumber kiln. Corners where walls meet should be sealed with expanding foam sealant. Dehumidification Kiln Drying. Adjust the baffles or fan direction to achieve good airflow. 6 0 obj Extruded polystyrene foam (blue or pink rigid foam) in this thickness has an R value of 10. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). Any small building could work, as long as it has a minimum of 2 x 4 framing, and will seal out unwanted air. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. Matched to one of our L-Series and HT Dehumidifiers they can handle whichever species you are drying, fast drying softwoods to slow drying hardwoods. Air drying to 6 - 8% MC is a very long term proposition and I'm not a patient man so I wanted a means to finish dry lumber after air drying outside to the EMC of my area of around 12 - 14%. Custom Doors, Drawers & Glass Accessories, Using a Small Scale Dehumidification Kiln, Learn Woodworking Tips & Tricks with Rockler, High-quality brands and products you can trust, Expert advice and free post-purchase support, Exclusive, innovative products that help you Create with Confidence, Detailed instructions, technical specs and guides to make the most of your purchases. Another common sticker size is 1 x 2, and these work fine as well. But kiln drying may also introduce internal stresses into the woodparticularly if an improper kiln schedule is used, . Low temperatures can be used for an extra safety margin on greener lumber. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. noun. For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. Created and Presented by: Henco Viljoen and Elijah McCarty with Nyle Dry Kilns. Please refer to Appendix A which shows the Lumber Dry Kiln Bill of Materials. Lay down the bead of caulking before raising the walls. Operates at a temperature range from 80F - 160F (26 - 71C). This, of course, is gross savings; we must calculate electrical costs to determine the net savings: in this case, about $62. squares, handle stock, gunstock blanks) are given for many species. In smaller kilns, the heat generated by the fans and DH motor is sufficient to maintain temperatures in excess of 100 degrees. Nyle - L300, L500, L1200-S Series - Kiln Drying Systems - Dry 1998. by Dr. Eugene Wengert. Academia.edu no longer supports Internet Explorer. hTn8>_l7h.&E:Bem=C9n\8]lMPc. Inexpensive Dehumidification Kiln - YouTube Remove samples from the stack, and cut an inch or two off one end. Wood Drying/ Seasoning. The velocity through the load is assumed to be between 275 and . It is a good idea to sterilize the lumber at the end of the kiln run. Wood Drying Kiln Technologies - XINAN Wood drying Kiln The thinner the stock, the more critical sticker placement becomes. You can achieve top-quality results with incredible efficiency. There is a way to do the conversions and there is a chart published by Nyle to do it, if you want to do some academic exercise. Take a moisture reading in the end grain with a pin-type moisture meter or remote probe. Size and placement of the access door are critical as well. The following tables show some examples of oak schedules for steam dry kilns and dehumidification dryers. As you can recycle . Temperatures inside the kiln range from 120 to 190 degrees F, depending on the stage of . For DH kilns, use the same RH, but lower the temperature to the typical operating temperature for the compressor; raise temperature to steam values when convenient and possible. Know how to choose and apply the correct schedule for the lumber. It uses a simple humidistat to control the dehumidifier, and a remote bulb thermostat to control the heater, which is a couple of light bulbs. Insulate the floor with 2 rigid foam for convenience and durability. Reply. This allows for a more gentle kiln schedule to fully dry the timber. The schedules can also be formulated manually as follows. /Name /ImagePart_0 Another common sticker size is 1" x 2", and these work fine as well. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. Reweigh and obtain the oven dry weight. If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. Joining end grain to long grain forms the king of joints. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. Operation and cost of a small dehumidification dry kiln Question Kiln-Dried Wood | Everything You Need to Know in a Nutshell If for any reason you are not satisfied with the merchandise you ordered, just return it within 90 days to receive a refund in the manner of original payment for merchandise only.