% *^2r_WT& / f' / c-s&-c- /7*' 
 
 FOREST PRODUCTS LABORATORY t FOREST SERVICE 
 U. S. DEPARTMENT OF AGRICULTURE 
 
 SMALL SAWMILL IMPROVEMENT 
 
 PRACTICAL POINTERS TO FIELD AGENCIES 
 
 PLANS FOR SMALL MILL LUMBER TREAT ING EQUIPMENT 
 
 Variations of an elementary type of tank (.1*3222)* involving hand dipping are used 
 where frequent moves diotate very portable equipment. Herewith are specifications for 
 treating equipment eliminating hand dipping. 
 
 The gravity dip tank (fig. l) in the plan shown is placed alongside the rolls and 
 immediately beyond the swing "trimsaw. The trimsaw operator tips to the inclined skids the 
 boards to be dipped. The slope and length adjustment of the l-l/2-inoh pipe skids are 
 such that the weight of the boards being tipped off the rolls pushes the other ones through 
 the liquid to the discharging side. Normally excess liquid drains off the board and into 
 the tank as the board emerges and before it drops to the skids at the discharging side. 
 This equipment permits dipping 2M board feet per hour. 
 
 The conveyor chain dip tank (fig. 2) is usually plaoed so that the lumber, after 
 trimming, is conveyed through the tank and thence to the sorter ohain. Power for driving 
 the oonveyor chains applied to the sprockets on the shaft at the entering side of the 
 tank and the rider wheels insure submergence of the chain and conveyed material. Strap 
 iron 3 inches wide fastened to the tank under the chains prevents excessive wear and the 
 angle iron section serves to guide the ohain. The chain has no lugs. The tank is floored 
 with a double layer of 1 by 6 tongue-and-grove material staggered as shown (fig. 2, B). 
 The rider wheels (iron pulleys) hinge on a frame supported above the tank. The least 
 waste in liquid results when the speed of the ohain is the minimum required to move produc- 
 tion, and 3° feet per minute is suggested for mills with a capacity up to 2M board feet per 
 hour. For higher speeds, the length of the 10-foot section (fig. 2, B) should be increased, 
 Approximately 130 gallons of liquid will suffice to keep the dip to the level shown, and 
 the tank should have outlets permitting drainage and cleaning. A mixing tank of at least 
 50 gallons capaoity and a shelter over all oomplete the equipment. 
 
 (Contributed by C. J. Telford, Forest Products Laboratory, January 19, 19^2.) 
 
 
 ROLLS 
 
 TANK 
 
 7^ 
 
 
 
 
 
 
 ! ' 
 
 1 
 
 
 
 
 lj PIPE , 
 
 > 
 
 HLZ 
 
 - ! 
 
 '— 14' - • 
 
 
 I 
 
 J4 
 
 
 ROLL 
 
 SOLUTION 4 m BClOv 
 TOP OF TAHH-i 
 
 side view 
 
 END VIEW 
 
 BOLLS-* 
 
 TANK- 
 
 lv',£ LIBRARY 
 jjJCT wl 197? 
 
 I.F.A.S. • Univ. of Florida 
 
 fig. r~— 
 
 GRAVITY DIP TANt 
 
 1 Maintained at Madiion, Wisconsin in cooperation with the University of Wiicon*»r 
 
 
 
 •See outline in Small Sawmill Improvement Working Plan, March 1930, for explanation of indexing iy»t« 
 RS99-15 
 
 spoted. 
 
 Z M l*.0076 F 
 
UNIVERSITY OF FLORIDA 
 
 3 1262 08926 8709 
 
 MIXING TANK 
 
 POWER APPLIED 
 TO THIS PULLEY 
 
 8- DETAIL CONVEYOR CHAIN 
 
 CHAIN 
 
 if 
 
 1 
 
 C -DETAIL RIDER WHEEL 
 
 Z U 40075 F 
 
 CONVEYOR CHAIN DIP TANK