Belt conveyor-manufacturing & utilization

1. Belt conveyor
Ashish kumar jain

2. WHAT IS BELT CONVEYOR?
 A belt conveyor is a large rubber band stretched between two (or
more) pulleys, traveling at a more-or-less consistent, more-or-less
high rate of speed, carrying a quantity of materials.
 In cement plant belt conveyor is used to convey crushed
limestone, coal, gypsum, clinker etc.
 Belt conveyors, with their stackers and reclaimers are the only practical
means for large scale stock piling and reclaiming of bulk materials

3. Terminologies of Belt
Conveyor

4. Belt Elements
 (1) Synthetic fabric layers
 (2) Shock absorbing rubber layers
 (3) "top" and "bottom" abrasion and
cut resistant rubber covers Fig. 1: Fabric belt

5. Idlers
Troughing idler
Training Idlers
Impact idler Return idlers
'V' return idler

6. Pulleys based on laggings
Diamond grooved lagging ‘V’ grooved lagging
Grooved lagging pulleys are generally used for head pulley and snub pulley.
Plain lagging pulleys are specially used for tail
pulleys, take-up pulleys which require good
traction between belt and pulley for improved
belt tracking capability
Plain lagging

7. Weighted
tension
pulley
Take up
weight
screw
Sliding bearing
block
Screw tensioning-In it the
tail pulley is installed over
rails so that it can be
removed by means of
screws. It is commonly
used on conveyors up to
75meter in length
Screw tensioning
Vertical gravity take-up Horizontal gravity take-up
Take-ups
Gravity take-up- It is self
adjusting and the tension on
the belt can be accurately
controlled by weights.

8. Selection of belt conveyor
 1. Tension Rating (Tensile strength of the belt)
 2. Load Support (Min no of plies)
 3. Troughability
 4. Pulley Diameters
 5. Belt thickness

9. Good Loading Conditions
When in service, belt wear occurs mainly at loading points, so to prevent wear:
 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.
 Boards and the belt clearance should increase in the direction of travel to prevent trapping.
 Ensure that the delivery chute is not choked.

10. Loading chutes
Fig. 1: Feed chute with curved
loading plate for material speed-up
Fig.3 feeding chute with rock box
Fig. 3: Example cement feed chute
Rock box arrangemnt

11. Maintenance
ITEM DAILY WEEKLY MONTHLY YEARLY
Gear box •Noise level
•Oil level
•Oil
Temperature
•Vibration
•Properties of oil (quarterly)
•Alignment of couplings
•Oil change not to
exceed 18 months or
(1500-5000hrs,
depending upon
condition of oil)
Couplings - -
•Oil level is checked for
fluid coupling
•Tightness of the bolt
•Alignment (recommended)
•Temperature for fluid
coupling.
•Check condition of gear
coupling teeth quarterly.
-
Bearings -
•Check for dust
accumulation
(recommended)
•Clearance
•Quarterly greasing is
done depending upon
condition.
-
Idlers
•Noise level
•Jams (if
any)
- - -
Pulleys
- •Laggings
should be
checked
•Quarterly alignment is
checked
•Tensioning bolts condition.
-

12. Troubleshooting
Sr. No. TROUBLE REASON
1 Swaying of belt
(i) Material having high moisture content.
(ii) Guide pulley jammed.
(iii) Improper belt joints.
(iv) Uneven wearing of lagging on pulley.
(v) Return and carrying idlers are not parallel.
2 Slipping of belt
(i) Malfunctioning of the take-up pulley.
(ii) Absence of proper lagging on head, snub and tail pulley.
(iii) Wet belt.
3
Rapid wearing in
belt
(i) Material that has been entrapped between belt and pulley.
(ii) Belt is in contact with any protruding part.
(iii) More falling height of material at transfer points.
(iv) Inadequate distance between impact pads and belt at transfer points.
(v) Inadequate distance between sealing blocks and belt.
4 Belt joint failure
(i) Uneven overlapping.
(ii) Air bubble left at the time of joining.
(iii) Wet conveying material (for cold joint).
(iv) Applying load before curing period.
(v) Joint steps are in wrong direction.
(vi) Insufficient temperature applied during joining process (for hot joint).

13. BC-4 Driving unit
FLUID COUPLING PIN BUSH COUPLING
HELICAL GEAR BOX
(20:1)
MOTOR(45 KW)

14. Belt repair procedures
MECHANICAL FASTENED JOINT
HOT VULCANISATION
COLD VULCANISATION

15. Field instrumentation
Item Description Function when actuated
1 Misalignment detector
Trip belt if seriously
misaligned
2 Under speed switch
Trip drive and feeding
conveyor
3 Pull wire and switch
Trip drive and feed
conveyor
4 Emergency stop
Trip drive and feed
conveyor
5 Rip detector
Trip drive and feed
conveyor

16. DUST SUPPRESSION
Dust generation depends upon:
1. The nature of material carried.
2. The height of drop on to the belt.
3. The speed of the belt.
4. The angle of loading and
unloading.
Dust curtains
Hood and spoon arrangement

17. Dry fog dust suppression
A bag is hanging to allow
the air pass
Water forced through nozzle
with air helps in dust
suppression

18. Dust suppression nozzle
resonator
nozzle body
Water holes Compressed
air
Dry fog

19. Recommendations
Gap from where the
material may come out
Full sealing material
will not come out
1.Rubber skirts are cheaper than
skirt pads
2.Easy install and removal
3.Can be made from used belt
conveyors

20. Recommendations
1.Impact idlers providing line contact to belt
2.Belt sagging can take place.
1.Impact pad providing surface contact
2.No chance of sagging of belt

21. Safety
 Should not load the material on the conveyor above its conveying capacity.
 While lubricating pulleys, idlers, bearings, fluid couplings and balancing the belts, the
conveyors should be stopped.
 It is dangerous to travel or walk across the conveyor (whether above or below it) while it
is running. It will be better to use cross overs and ladders provided for this purpose.
 While walking along the sides of conveyor belt in belt conveyor gallery for inspection
purpose, always ensure that your hands, legs, head and hair are not in touch with the
moving belts and idlers. NO LOOSE GARMENTS TO BE WORN DURING WORK.
 The belt conveyor gallery should be well illuminated. The non burning lamps should be
replaced with new ones immediately.
 The switches like limit switch, belt sway switch, starting and stopping switch and
mechanical/electrical interlocking switches should be checked periodically to know
whether they are in good operating condition