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Martin Engineering helps belts handle tour of duty

Martin Engineering

As one of the leading designers and manufacturers of belt conveyor accessories, Martin Engineering recommends some key considerations to ensure your site gets the most out of the conveyor belt’s lifespan.

With constant exposure to raw and abrasive materials and harsh weather conditions, few parts wear faster in the quarrying industry than conveyor belts.

Due to the duress of these punishing conditions, most sites have experienced critical failures with conveyor belts, commonly from splice failure, piercing damage or chronic issues including mistracking and frozen idlers.

In some circumstances, damage can strike from a one-off event like tramp metals or oversized lumps impacting the belt from the material flow stream. Often these events can lead to immediate shutdowns for repairs, project delays, and missed deadlines.

Given the significant cost of downtime and lost production on-site, knowing how to avoid conveyor belt wear and extend its performance and life is vital.

Properly positioned and tensioned primary and secondary cleaners
mitigate belt wear issues commonly associated with cleaners.

While belt cleaners can wear the conveyor belt, they do so at a much lower rate than loading practices do.

Belt wear during loading generally occurs over a significant period from abrasive raw materials impacting the belt. Components, like seized idlers from fouling and improperly tensioned belt cleaners, can further contribute to wear. Combined, these factors can create a two-fold dilemma with impact damage and frictional wear.

To reduce loading wear, sites should consider adopting a curved chute design. Curved chutes allow the material’s stream velocity to closely match the speed of the belt.

Compared to a flat chute, a curved chute will deliver a reduced impact velocity even if the basic discharge angles are similar. The benefits of a well-designed chute can be enhanced by paying significant attention to the selection of liners.

Flat chutes can create greater impacts depending on the drop heights which takes a constant toll on the belt and creates fugitive materials like dust and spillage.

Martin Engineering’s Todd Swinderman recommends viewing wear liners as ‘sacrificial components’ and spending more time improving chute design with lower friction liners to make them easier and quicker to change.

Improved design can be achieved by utilising discrete element modelling (DEM).

DEM has provided the quarrying industry with a valuable tool for verifying and optimising chute designs as well as predicting conveyor belt wear life.

Since idler and pulley fouling lead to significant belt wear on the unprotected return side, eliminating fugitive materials as much as practical can benefit a company seeking to extend its conveyor belt life.

The US Mine Safety and Health Administration estimates that 85 per cent of all conveyor problems – including wear – come from fugitive materials.

Spillage, dust and carryback in the discharge zone can build up and encapsulate the belt, contributing to belt and conveyor wear, which is why Martin Engineering recommends undertaking adequate belt cleaning.

In severe cases of damaged belting with divots, cracking and skirtboard grooves, the company suggests employing a wash box using water sprayers along with mechanical scrapers or rotating brush cleaners.

A belt cleaning station can keep a belt, which is in good condition and professionally maintained, in good condition and limit carryback to within 10-100 g/m2.

While it is a common expectation that a conveyor belt can be cleaned with an efficiency approaching 100 per cent, even a brand-new belt has macro and micro defects that make cleaning close to 100 per cent practically impossible.

These imperfections can result in as much as 60 g/m2 of carryback passing a belt cleaner station with a new belt. When the belt surface is damaged, the amount of carryback that can be shielded from belt cleaning in scratches and gouges can be even more significant, on the order of 100 to 200 g/m2.

The Conveyor Equipment Manufacturers Association established a system for rating the difficulty of the belt cleaning application and for desired levels of carryback exiting a cleaning station in its seventh edition of Belt Conveyors for Bulk Materials.

This aids users in specifying belt cleaning performance, rather than making decisions based on brand preference or price alone.

With these solutions in mind, companies can extend the life of conveyor belts across the work site which will have significant follow-on effects, like reduced downtime and optimising the value of a major cost element.

For more information, see martin-eng.com.

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