Page 43 - HUB-4 Magazine Issue 85

Quarrying News
Copyright © Martin Engineering 2024
Belt tracking keeps loads centered and minimizes dust from spillage and disruption.
Dust at the Discharge Zone
More often than not, the conveyor discharges down an open shaft with a dead drop into the transfer chute leading to another conveyor, into a hopper or silo, or onto a storage pile. When the material leaves the belt, it separates, exposing the entire stream which allows smaller particulates to become airborne. Stacker conveyors and tripper conveyors are especially prone to this and often utilize a misting ring or specially designed sock to control the stream.
However, material often hits the back of the transfer chute or impacts on rock boxes which can result in dust blowing back up the chute. Enclosing the discharge zone and controlling the impact of material using a spoon design will mitigate blowback. Also, adding air cannons helps direct cargo and airflow, as well as prevent unscheduled downtime from buildup and blockages within the chute.
Dust on the Return
Conveyor belts across all bulk handling sectors take a tremendous amount of punishment and the single most expensive piece of equipment on the conveyor system is the belting. No matter how careful the upkeep, the belt will eventually start to show divots and cracks. The weight of the cargo can cause dry material to stick to the surface and dust and fines collect in the flaws. If not properly cleaned, the adhered material will not be discharged with the cargo flow and remain on the belt as carryback, spilling fines and emitting dust along the return path of the system.
Primary cleaners remove the most abrasive and hardest material left on the belt after discharge. Mounted at the head pulley on a tensioned assembly and the engineered polyurethane construction, many blades are in a curved configuration that allows the blade tip to fit snuggly against the belt and wear evenly throughout the blade’s life with only minor adjustments to the tensioner. One innovative primary cleaner design requires no tensioning at all after initial installation. It features a matrix of tungsten carbide scrapers installed diagonally to form a 3-dimensional curve around the head pulley and typically delivers up to 4 times the service life of urethane cleaners without ever needing re-tensioning.
Copyright © Martin Engineering 2024
The low-profile primary cleaner takes up less space than standard cleaners.
Secondary and tertiary cleaners are located immediately after the belt leaves the head pulley to address dust and fines that escape the primary cleaner. Generally equipped with spring or air tensioners that easily adjust to fluctuations in the belt, secondary and tertiary cleaners dislodge dusty carryback, adding it back into the cargo flow.
Case Study – Coal Mine - Shandong Province, China
A coal mining facility in Eastern China with a production capacity of approximately 1 million TPY experienced dust and spillage from one of its main conveyors. Fugitive dust drastically lowered the workplace air quality and clogged equipment. Breakdowns of rolling components caused misalignment of the belt leading to spillage along the belt path. Piles of spillage blocked access to the system and walkways, which had to be cleaned requiring extra labor and raising the cost of operation. Internal resources attempted to fabricate an enclosure to contain dust emissions but it proved to be unsuccessful and dangerous to maintain.
www.hub-4.com March/April - Issue 85
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