Loading Points
Good Loading Conditions
When in service, belt wear occurs mainly at loading points. Wear factors include feed direction relative to belt movement, belt speed, material characteristics and the impact of the lumps on the belt.
Loading should be central with material feeding at same speed and in same direction as belt travel
Reduce the free fall of material at loading point.
Cushion lumps by screening out fines in front of the toe of the chute.
Use impact idlers to absorb the impact energy of the lumps.
If skirting is used keep it just clear of the belt. At loading points the distance between skirt boards and the belt should increase in the direction of travel to prevent trapping.
Ensure that the delivery chute is not choked.
Skirt Boards
The use of skirt boards is an accepted practice used to centre and settle the material on the belt as it leaves the loading point. The skirt boards should be vertical or inclined slightly outward at the top and set approximately one-sixth of the belt width in from each edge. Initially the opening is two-thirds of the belt width and then tapers out in the direction of the belt travel. The length should be sufficient to properly centre and settle the load and generally is 4-5 times the belt width in length. The skirt board is never brought down tight against the belt surface, but is left with a substantial clearance (approximately 1 in minimum) which is then closed with a rubber strip. The clearance between skirt boards and belt should increase in the direction of belt travel to permit freeing of any trapped material.
To further insure against trapping material here, the strip of rubber should be fitted on the inside of the skirt board. Skirt boards can be termed 'necessary evils' and if not properly set can damage the belt cover.
Screen Bars
The incorporation of screen bars into the back plate or a chute, when handling lumpy materials mixed with fines will allow the fines to fall through first and form a bed or cushion to help absorb the impact and minimise damage to the belt cover.
V-Slots
A 'V' slot cut in the bottom of the chute is another satisfactory method of allowing fines to fall on the belt before the lumps.