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ENGINEERING & TECHNICAL INFORMATION

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Trouble Shooting

Solving the problems that can be experienced with a belt conveyor can be accomplished if the problem is
analyzed carefully. To begin with proper installation is critical for efficient operation of the system. Proper
maintenance and care are also highly important. Many problems result from these two issues and abuse of
the system and related components. The following chart is provided to list some common problems associated with belt conveyors and the common ways to resolve these problems. If additional advice is needed please contact Douglas Manufacturing and we will attempt to assist in the resolution of these problems.

Solutions to Problems

#

Cause

Solution

1

Belt bowed

Avoid telescoping belt rolls or storing them in damp locations. A new belt should straighten out when “broken in” or it must be replaced

2

Belt improperly spliced or wrong fasteners

Use correct fasteners. Retighten after running for a short while. If improperly spliced, remove belt splice and make new splice. Set up regular inspection schedule.

3

Belt Speed too fast

Reduce belt speed.

4

Belt strained on one side

Allow time for new belt to “break in”. If belt does not break in properly or is not new, remove strained section and splice in a new piece.

5

Breaker strip missing or inadequate

When service is lost, install belt with proper breaker strip.

6

Counterweight too heavy

Recalculate weight required and adjust counterweight accordingly. Reduce take-up tension to point of slip, then tighten slightly.

7

Counterweight too light

Recalculate weight required and adjust counterweight or screw take-up accordingly.

8

Damage by abrasives, acid, chemicals, heat, mildew, oil

Use belt designed for specific condition. For abrasive materials working into cuts and between plies, make spot repairs with cold patch or with permanent repair patch. Seal metal fasteners or replace with vulcanized step splice. Enclose belt line for protection against rain, snow, or sun. Don’t over-lubricate items.

9

Differential speed wrong on dual pulleys

Make necessary adjustments.

10

Drive under-belted

Recalculate maximum belt tensions and select correct belt. If line is overextended, consider using two-flight system with transfer point. If carcass is not rigid enough for load, install belt with proper flexibility when service is lost.

11

Edge worn or broken

Repair belt edge. Remove badly worn or out-of-square section and splice in a new piece.

12

Excessive impact of material on belt or fasteners

Use correctly designed chutes and baffles. Make vulcanized splices. Install impact idlers. Where possible, load fines first. Where material is trapped under skirts, adjust skirtboards to minimum clearance or install cushioning idlers to hold belt against skirts.

13

Excessive tension

Recalculate and adjust tension. Use vulcanized splice within recommended limits.

14

Frozen idlers

Free idlers. Lubricate. Improve maintenance. (Don’t over-lubricate)

15

Idlers or pulleys out-of-square with center line of conveyor

Realign. Install limit switches for greater safety.

16

Idlers improperly placed

Relocate idlers or insert additional idlers spaced to support belt.

17

Improper loading, spillage

Feed should be in direction of belt travel and at belt speed, centered on the belt.
Control flow with feeders, chutes, and skirtboards.

18

Improper storage or handling

Refer to the manufacturer for storage and handling tips.

19

Insufficient traction between belt
and pulley

Increase wrap with snub pulleys. Lag drive pulley. In wet conditions, use grooved
lagging. Install correct cleaning devices for safety. See Item 7, above.

20

Material between belt and pulley

Use skirt-boards properly. Remove accumulation. Improve maintenance.

21

Material build-up

Remove accumulation. Install cleaning devices, scrapers, and inverted “V” decking. Improve housekeeping.

22

Pulley lagging worn

Replace worn pulley lagging. Use grooved lagging for wet conditions. Tighten loose and protruding bolts.

23

Pulleys too small

Use larger-diameter pulleys

24

Radius of convex vertical curve too small

Increase radius by vertical realignment of idlers to prevent excessive edge tension.

25

Relative loading velocity too high or too low

Adjust chutes or correct belt speed. Consider use of impact idlers.

26

Side loading

Load in direction of belt travel, in center of conveyor.

27

Skirts improperly placed or not maintained

Install skirtboards so that they do not rub against the belt.

28

Wear liners missing, worn or improperly installed

Replace wear liners so the bottom edge is lined up and gradually relieving in direction of belt travel.

29

Belt overloaded

Operate belt feed system at design capacity or less.

30

Excessive belt sag

Recalculate take up tension. Install belt support system or reduce idler spacing.

31

Belt rolls back after shut down

Install or repair belt holdback or brake.

32

Insufficient number of belt cleaners or lack of maintenance

Install additional belt cleaners or maintain existing cleaners more frequently.

33

Bulk material properties have changed

If a permanent change in bulk materials, redesign chutes, belt cleaners and re-evaluate conveyor speed, tension and belt type.

34

Emergency repairs or actions

Repair temporary fixes. Install accessory items to automatically activate. Avoid heating or hammering of hoppers, chutes and components.

35

Monitoring devices inoperable

Repair or activate monitoring devices.

Problem or Symptom

Reason Code
In Probable Order of Occurrence

Belt runs off at tail pulley

7

15

14

17

21

34

Entire belt runs off at all points of the line

26

17

15

21

4

16

One belt section runs off at all points on the line

2

11

1

34

Belt runs off at head pulley

15

22

21

16

34

Belt runs to one side throughout entire length at specific idlers

15

16

21

34

Belt slip

19

7

21

14

22

Belt slip on starting

19

7

22

10

Excessive belt stretch

13

10

21

6

9

Belt breaks at or behind fasteners or fasteners tear loose

2

23

13

22

20

10

Vulcanized splice separation

13

23

10

20

2

9

Excessive belt wear including rips, gouges, ruptures and tears

12

25

17

21

8

5

Excessive belt bottom cover wear

21

14

5

19

20

22

Excessive belt edge wear, broken edges

26

4

17

8

1

21

Belt cover swells in spots or streaks

8

Belt hardens or cracks

8

23

22

18

Belt cover becomes checked or brittle

8

18

Longitudinal grooving or cracking of belt top cover

27

14

21

12

Longitudinal grooving or cracking of belt bottom cover

14

21

22

Belt Fabric decay, carcass cracks, ruptures, gouges (soft spots in belt)

12

20

5

10

8

24

Belt ply separation

13

23

11

8

3

Build up on Bend Pulleys and return idlers

32

33

8

22

Spillage of fines and small particles in loading area

27

28

17

12

30

Spillage of larger particles and lumps along conveyor

15

29

30

31

35

Plugged Chutes

35

33

34

31

Damaged to accessories in contact with the belt

31

2

11



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All dimensions and specifications subject to change without notice. Certified dimensions and specifications of ordered material available on request.
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