Increase conveyor belt life while reducing costs

By |  November 17, 2020
Photo: WCCO Belting

The fabric requirements for conveying aggregate materials involve tensile strength, tear strength and puncture resistance – but not in the order one might think. Photo: WCCO Belting

Operators want the toughest conveyor belt for the job when moving aggregate materials.

Longstanding product specs call for high-tensile strength, a thick rubber cover and multiple fabric plies. Yet, when the conveyor system is running empty and waiting to discharge, system efficiency and energy savings directly impact profitability. The heavier the belt, the higher the cost to move it. But most consider it a necessary evil.

A research article Hindawi published in 2019 in Mathematical Problems in Engineering concluded that as much as 60 percent of the energy consumption of a system is attributed to the conveyor belt. The authors also shared that this percentage can be decreased by managing certain factors of the belt – one of which is indentation rolling resistance (IRR).

What is IRR?

IRR is the primary resistance generated during the stable operation of the conveyor system. It occurs when the conveyor belt is under compression over rollers and pulleys, leading to a resistance on the system to advance the belt forward. This resistance is overcome by increasing the demand on the motor, rollers and bearing, thus increasing the cost to operate. It takes a certain amount of energy to cycle the belt, and the higher the IRR, the more energy needed – and the more strain placed on auxiliary components.

The leading factors that contribute to increased levels of IRR are the belt cover thickness, rubber type, overall gauge and belt flexibility, meaning there are more opportunities to reduce rolling resistance – beyond belt weight and mass – through raw material inputs and belt composition.

Increasing cover thickness in hopes of extending belt life will result in higher upfront costs, negatively impact energy consumption and wear on auxiliary components. Likewise, increasing tensile strength for belt longevity, in most cases, will not address the true failure modes of the belt carcass. Additional thickness and stiffness will simply generate higher levels of IRR and reduce productivity.

New realization

Photo: WCCO Belting

The rubber compound used on the belt’s cover can be formulated to match aggregate requirements. Increasing the cover compound’s abrasion resistance property improves cover protection. Photo: WCCO Belting

Modern belting technology can do more than withstand the demands of heavy conveyor operations. Rubber compound development and textile engineering made significant advancements that should be taken into consideration during belt selection. With an understanding of the requirements of the belt in relation to the application’s unique conditions, operators can increase belt life while reducing operating costs.

Qualified belting manufacturers have the ability to tailor belt properties to achieve the highest levels in performance, longevity and efficiency. While it may be easier to pick a product out of a catalog, procuring the right belt for the job will pay back in spades. It’s the primary component of the conveyor system.

The design and manufacturing that goes into the belt is a science. The rubber compound used on the belt’s cover, for example, can be formulated to match aggregate requirements. Increasing the cover compound’s abrasion resistance property improves cover protection. If a cut or gouge does occur, increasing the compound’s tear strength property helps to prevent the tear from propagating and exposing the fabric where the belt’s primary strength properties reside.

The fabric requirements for conveying aggregate materials also involve tensile strength, tear strength and puncture resistance – but not in the order one might think. From a belt’s perspective, its first line of defense is the rubber cover. Its next line of defense is the fabric’s ability to resist punctures if a cut or gouge gets past the cover protection. Then, the tear strength properties prevent the puncture from further tearing. Lastly, tensile strength provides protection through load support.

Additional insights

Belting that improves conveyor system efficiency while maintaining its durability for aggressive aggregate applications may seem too good to be true. Not only is it possible, but it results in real dollars to the bottom line. Field testing proved that modification of the raw material inputs improved belt life and reduced the key contributing factors to IRR: thickness and stiffness. As a result, energy savings may be boosted by up to 85 percent on a single unit.

Using this same design strategy, a case study revealed an increase in energy savings, as well as a 70 percent increase in belt life in a side-by-side comparison to an industry standard. Two belts with a similar tensile rating turn out to be incomparable in field performance due to the formulization of properties. Working with a belting expert can help you achieve these results.

Building a belt with the strength where it’s needed most, reducing properties not as critical to the application, and the cost associated with each deliver the most optimal solution for operations. The performance of the belt itself will improve in a way that benefits equipment health and life. In fact, operators can feel satisfied knowing that even if the conveyor is running empty, it’s saving them money.

Mike Schroeder is a product specialist at WCCO Belting.

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