FEED QUARTERLY Continued from page 48 Figure 2. Screw feeder capacity for various pitches BIN OUTLET (FLOOD FLOW) SHROUD Shroud Dia. DIA. A screw conveyor uses a helicoid metal strip wrapped around a center shaft forming a continuous spiral. This metal VWULSDWWDFKHGWRWKHFHQWHUVKDIWLVFDOOHGWKH³ÀLJKWLQJ´IRU the screw conveyor. The distance from the tip of the outer edge of the one revolution to the same spot on the next is FDOOHG ³SLWFK´ 6WDQGDUG SLWFK IRU FRQYH\RU ÀLJKWLQJ LV WKH VDPHDVWKHRXWVLGHGLDPHWHURIWKHÀLJKWLQJ7KXVDLQFK diameter screw conveyor would have an outside diameter of LQFKHVDQGHDFKUHYROXWLRQZRXOGPHDVXUHLQFKHVIURP RQHÀLJKWLQJHGJHWRWKHQH[WÀLJKWLQJHGJH ,QVFUHZFRQYH\RUVGHVLJQHGDVIHHGHUVWKHSLWFKRUGLDP HWHURIWKHÀLJKWLQJGLPHQVLRQVYDU\DFURVVWKHOHQJWKRIWKH LQOHW$WWKHSRLQWZKHUHWKHÀLJKWLQJOHDYHVWKHLQOHWDUHDD top shroud is installed in the conveyor. This shroud is at least WZLFHDVORQJDVWKHFRQYH\RUGLDPHWHU)RUDLQFKVFUHZ WKHVKURXGZRXOGEHLQFKHVORQJ The standard screw conveyor has a round bottom with VWUDLJKW VLGHV DQG D ÀDW WRS :LWK WKH VKURXG LQ SODFH WKH shroud length becomes a tube. The capacity of the feeder is the amount that passes through the shrouded area. 7KHUH DUH WKUHH ZD\V WR GHVLJQ WKH ÀLJKWLQJ DQG FRQYH\ or enclosure under the feeder inlet area before entering the 1/3P 1/3 P 1/2 1/2 Pitch PITCH 2/3 PITCH Pitch 2/3 Full Pitch FULL PITCH BARE Bare Discharge DISCHARGE VKURXG 7KH ¿UVW LV WR VWDUW WKH FRQYH\RU ZLWK VPDOO GLDPH WHU ÀLJKWLQJ WKDW JUDGXDOO\ LQFUHDVHV LQ GLDPHWHU WR WKH ¿QDO ÀLJKWLQJ GLDPHWHU DW WKH VKURXG HQWUDQFH 7KH WURXJK XQGHU the inlet must be shaped to be small at the beginning and grow to full size at the inlet to the shroud. A second method is to use IXOOGLDPHWHUDQGSLWFKIRUWKHIHHGHUEXWWKHVKDIWWKHÀLJKW ing is attached to starts large and decreases to standard size Better drying equals higher milling yield! SOLUTIONS FOR THE WORLD'S MOST IMPORTANT BUSINESS WWW.TORNUM.COM EVERYTHING YOU NEED FOR DRYING, STORING AND HANDLING GRAIN 52 February 2019 / World Grain / www.World-Grain.comhttp://WWW.TORNUM.COM http://www.World-Grain.com