Atnikov, David

Western Dry Kiln Association

Western Dry Kiln Association. Meeting (40th : 1989)

Undetermined

ScholarsArchive@OSU

OPPORTUNITIES PRESENTED THROUGH MOISTURESORTING OF GREEN LUMBER USING THENOVAX 8010 INFRARED MOISTURE SENSORDavid AtnikovNovax Industries CorporationNew Westminster, BCThe goal of any new technology is to conserve the resource while stillmaintaining or improving profitability. Timber cutting restrictions, increasing rigidenvironmental standards, and offshore quality requirements will all play a greaterrole in the lumber industry's future profitability,Each of the current techniques for sorting green wood materials by moisturecontent suffers from one or more of the following inherent drawbacks:1) sensitivity to variations in wood density2) mechanical drift3) requires precision volume measurements4) inappropriate above the fiber saturation point5) not non-contact6) species-dependent readingsResearch by scientists at the Forintek Canada Corporation resulted in apractical and effective method for sorting green lumber using infrared sensing.Commercial development and implementation of this method by Novax IndustriesCorporation has made it available to mills.BACKGROUNDNovax Industries Corporation has been involved in the design andmanufacture of control systems since 1965. Novax Industrial Control provides thecontrol electronics for much of the equipment manufactured by Durand Raute,formerly Durand Machine. The electronic design, development, and manufacturingexperience Novax has developed over the last 20 years proved to be a valuable assetwhen Forintek was considering a potential commercial development partner for theinfrared process. In early 1987, based on the results achieved during the initialWeldwood trials described below, an agreement was reached whereby NovaxIndustries Corporation purchased the right to manufacture and sell devices basedon the Forintek process under protection of the Forintek patent.TRIALSIn 1986 Forintek conducted a significant mill trial at Weldwood of WilliamsLake, BC utilizing the new infrared moisture sorting technology to assess theeconomic benefits of sorting green SPF lumber. The objectives were:1) determine improvements in grade and recovery, and2) establish reductions in drying time while meetingmoisture standardsThe results of this trial are shown in Figure 1. The Weldwood experience revealedsavings of $8.50 per 1000 board feet in grade and recovery, an increased recoveryof wet/dry sort over control of 3.45 percent, and a 22 percent reduction in dryingtime. With similar results, a mill operation with large production could save inexcess of a million dollars annually.105GROUP A - CONTROL-Not Measured by Sensor-Sample Above and Below 35% Moisture Content-Schedule 210° F Dry Bulb170° F Wet Bulb32 HoursKiln Charge - 176 MFBMGROUP B - WET SORT-Measured by Sensor-Sample above 35% Moisture Content-Schedule 210° F Dry Bulb170° F Wet Bulb32 HoursKiln Charge - 166 MFBMGROUP C - DRY SORT-Sample Below 35% Moisture Content-Schedule 210° F Dry Bulb170° F Wet Bulb20 HoursKiln Charge - 182 MFBMFigure 1. Kiln charges established for infrared moisture sorting trial at Weldwood.106In mid-summer of 1987 Novax industries entered into a cooperativerelationship with Riverside Forest Products of Lumby, BC. Riverside ForestProducts operates a stud mill with annual production of 70 to 80 million board feet.Riverside sought to achieve a reduction or elimination of drying time for dry sorts,a reduction in degrade by not overdrying, an improvement in volume recovery viaa reduction in splits and twists, and an increase in throughput at the planer.A number of factors make moisture optimization necessary. Natural growthand climate conditions, beetle kill, heartwood, and processing time all contributeto moisture variation in the green product. Based on these, it was determined thatwith three sorts material less than 22 percent moisture content could bypass thekilns, the lumber between 22 and 35 percent could have a reduced drying time, andthe lumber greater than 35 percent could have the current or a slightly extendeddrying time.At Riverside Forest Products approximately 3 to 8 percent of the materialwas dry enough to by-pass the kilns. Note, however, that for export (Australia)environmental regulations require approximately 6 hours at 165°F. In the middlemoisture content range drying time was reduced approximately 30 percent, graderecovery increased by 2 to 3 percent, and volume recovery increased approximately1 to 2 percent. Reduction of kiln time and planer downtime has increasedthroughput 2 to 3 percent. Specific runs have improved as much as 8 to 10 percent.As a result of the cooperation between Riverside and Novax, the design anddevelopment of the infrared sorter were streamlined. Many of the featuresincorporated into the sorter are a direct result of feedback from mill management.The moisture sensor is designed to improve the bottom-line results of a millthrough better recovery as opposed to increasing mill throughput. For a milloperation realizing 10 percent profitability, a 5 percent increase in throughput onlyincreases profits by 5 percent; whereas, a 5 percent increase in recovery willincrease profits by 50 percent, all other factors being equal.At West Fraser Mills, LDT. implementation of the system has resulted in15 percent of the lumber being under 20 percent moisture content, dryer savings of$7.00 per 1000bf, a 3 percent reduction in trim loss, and an $18,000 savings inplaner downtime. Total savings are estimated at $2.66 per 1000.CONCLUSIONForintek has developed a practical solution to the long standing problem ofvariation in green moisture content. Novax Industries Corporation has translatedthat solution into commercial reality with 5 operating infrared sorting installationsin the Pacific Northwest within one year of commercial availability.107

Opportunities presented through moisture sorting of green lumber using the Novax 8010 infrared moisture sensor

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Opportunities presented through moisture sorting of green lumber using the Novax 8010 infrared moisture sensor

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