conveyors continued
Figure 4—Wing pulley recycled material.
ley. It needs to be heavy, much like a rim to support the load. The wings are welded to the tube.
Having the wings at an angle also provides constant contact with the belt, reducing vibration and noise. The reduction in vibration is important at tail pulleys, as too much vibration will reduce the effectiveness of skirtboard seals.
A further reduction in vibration is possible by offsetting the wings. While moving the wings closer together will also reduce vibration and noise, it will also reduce the size of lumps the wing can handle. With the wings offset, the contact bars can be extended over the central disc, creating twice as many contact points at the center of the belt. This will further reduce vibration without adding wings and cost.
Figure 5—Tail pulley with bent wings.
While an angled wing provides a training effect, it only does so as the belt enters and leaves the pul- ley. This is very effective for small wraps, such as snub pulleys. It is only a minor effect on large wrap pul- leys, such as tail pulleys. To achieve a better train- ing action on tail pulleys, crown is important, but a full crown would put a lot
Figure 6—Cross sectional view of various pulley crowns.
48 www.coalage.com
November 2012