Reconditioning & Repairing of Used Belts

Reconditioning & repairing of fabric & steel cord belts (Conveyor Belt Repair / Reconditioning and Through Cut Repairs)

Conveyor belts are put out of use because of the following reasons.

Full life running | Longitudinal Through Cuts | Edge damage | Patch failure

Types of Repair:

Reconditioning –
The worn out top & bottom covers are put back to the desired thickness. Edge & Patch Repairs, if any are also attended.

Longitudinal Cut Repairs –
Belts which are longitudinally cut in two or more pieces due to foreign objects are brought back to the original width & strength by hot vulcanizing. Additional Belts for substitution at the cut area are provided by the customer.

Economics of Repair & Reconditioning:

It is highly techno-economically viable to undertake through cut repairs and/or reconditioning of the damaged conveyor belts. A new lease of life can achieved from the belts after investing about 40 -50 % cost, without sacrificing the reliability.

In fact in some cases, the life obtained from the reconditioned belt has been much more than that obtained from the original belt

Reliability:

The repair & reconditioning works are undertaken by equipment’s & facilities used for new belt manufacturing. All the parameters such as adhesion strength, cover grade & its properties, etc are similar to that of new belts. In fact in some cases, the cover grades can be suitably modified to attain higher life than that obtained by new belts.

Full Life Running:

Top & bottom rubber covers get worn out.
Belt are subjected to spot damages also.
Reconditioning: By attending the carcass and replacing top and bottom covers.
Economics: Cost - 60 - 65%, Life - 95 - 100%

Edge Damage Repairing:

Edges of the belt get damaged due to swaying of conveyor or other reasons.
This can cause further damage to the steel cords and can be arrested by repairing the edges.
Repair: Removal of damaged plies and substitution of additional plies.
Economics: Cost - 25 - 35%, Life - 95 - 100%

Longitudinal Trough Cut Repair:

The belt is cut into two or more pieces longitudinally & sometimes the entire length of the belt.
Repair: Belt stepped longitudinally, additional plies substituted and vulcanized to parent belt carcass.
Economics: Cost - 40 - 45%, Life - Full Residual Life

ADVANTAGES OF RECONDITIONING:

Preservation of Natural Rubber which is a scarce natural Resource
Greenhouse gas reduction
Clean Air and waste reduction

COMPARISON OF REPAIRED VIS –A- VIS NEW BELTS OF M24 GRADE.

S. No. Description of Test Unit IS Values Our Values
1 Tensile Strength MPa 24 24.5
2 Elongation % 450 475
3 Accelerated Ageing Test +10 to −20
(a) % Change in Tensile Strength % −7
(b) % Change in Elongation % −9
4 Adhesion Test
(a) Rubber – Ply Kn/mtr. Width 3.5 3.8
(b) Ply – Ply Kn/mtr. Width 4.5 5.6

PERFORMANCE – REPAIRED / RECONDITIONED BELTS

The high reliability of belt after repair / reconditioning is achieved due to the following reasons:

Old belt accepted only if strength is 80 % minimum.
Process similar to new belt manufacture.
Repair materials manufactured in adjacent premises.
Repair material used within 2-3 days of manufacture. Nil deterioration in shelf life, hence very high adhesive values.
The adhesion strength of the substituted plies with the parent belt is above the minimum stipulated values resulting in very high reliability of the repaired belts.
Repaired portion becomes an integral portion of the parent belt.