A belt tripper is an unloading device which consists of two pulleys, of comparable size of the head pulley, supported in a fixed or movable frame. One pulley serves to elevate the belt a sufficient height from camying rollers to permit a discharge chute to be under pulley. The te receives the entire amount of material flowing over the pulley and dis- charge it on one or both sides of the conveyor The belt passes around the second pulley and beneath the chute, toresume is tion on carrying rollers. outer sun of the belt a wiper or scraper blade is used Bet for dry panels adhering to the belt. A rotary brush type cleaner is used for wet and sticky materials. To clean the inner surface of belt. if w arranted, a scraper is placed near the end of retum run before the sil en4pulley, (h) Training idlers: For various reasons like eccentric loading. sticking of material to belt or dlers etc., particularly for a long-centre conveyor, the belt may tend to move out of centre line. To prevent this tendency. belt training idlers are used which automatically maintain belt alignment. The belt ning idler consists of an ordinary troughed idler which is mounted on its base by pivot shaft about which it can swivel within a limited angle. Two short vertical rollers. mounted on bearings are fixed at the two ends of the idler, such that they are perpendicular to the belt edges. The vertical rollers are placed slightly ahead of the idler centre line When the belt shifts off centre, it makes contact with one of the vertical rollers which makes the entire idlers frame to swivel through an angle. This skewed position of the idler creates a force which tends to bring the belt back to its central position. In a long conveyor such trainer idlers may be spaced at about 30 meters. Fig. 6.1.10 shows such a troughed belt training idler.