After almost 30 years of utilization, a North-American Silver- and Gold-Mine took action together with specialists of Martin Engineering to update its conveyor system with improvements regarding safety, spillage reduction, endurance and efficiency.
Robert Stepper, Richard Shields
(ed. wgeisler - 27/2/2017)
The chute was then fitted with an abrasion-resistant external wear liner, another design upgrade. Previous wear liner designs were welded to the inside of the chute, with only the skirt seal located on the outside. The logic behind this conventional design is for the wear liner to protect the skirtboard, which is typically ¼ inch (.64 cm) sheet metal and not strong enough to withstand the sustained force and abrasion from bulk material.
Unfortunately, the wear liner is essentially a sacrificial layer, and the eventual removal/replacement of this design requires confined space entry, multiple workers and days of downtime. Instead, Martin Engineering designers came up with the idea of raising the chute work about 4” (10.2 cm) above the belt, then putting the wear liner on the outside. Using this approach, the material still hits the liner and doesn’t damage the chute. The result is significantly reduced installation and service time, with reduced risk during service.
At the bottom of the wear liner an 84 linear feet (25.6 m) Martin Apronseal double skirting delivers two wear surfaces on a single elastomer sealing strip. When the bottom side of the sealing strip is worn, it is just inverted, providing a second service life.
The design was the first dual-sealing system for belt conveyors, incorporating a primary seal clamped to the steel skirtboard to keep lumps on the belt and a secondary or “outrigger” strip to capture any fines or dust particles that pass beneath the primary seal. The secondary seal lies gently on the belt and self-adjusts to maintain consistent strip-to-belt pressure.
The primary seal is clamped to the steel skirtboard and a secondary “outrigger” strip captures the fines.
To maintain a straight and consistent belt path, technicians then installed a Martin heavy duty upper and lower belt tracking systems. Rollers attached to the end of sensing arm assemblies ride on both sides of the belt edge to detect slight misalignments initiated by unbalanced loads and fouled rollers, using the force of the belt to immediately adjust the belt’s position and realign the path.
To address belt carryback and further reduce the chance of fugitive material, a dual belt cleaner system was mounted on the face of the head pulley. The primary unit is a QC1 cleaner XHD, engineered to deliver durable belt scraper performance in challenging applications. The unit’s patented CARP (constant angle radial pressure) design maintains cleaning performance through all stages of blade life.
Directly after the primary cleaner is a DT2 inline cleaner XHD, a secondary conveyor belt scraper featuring rugged blades, with its installation allowing quick blade replacement to increase the conveyor’s availability. The design’s individual belt cleaner blade segments slip into a sturdy track-forming cartridge, which slides over the stainless steel mainframe for simple installation.
A final belt protection mechanism was installed at the tail pulley. To fight the potentially damaging effects of fugitive material on the return side of the belt, the Martin Torsion V-Plow is engineered with a unique spring-loaded suspension system that allows the plow to rise and fall with fluctuations in belt tension and travel. Attached with dual steel crossbars bolted to the conveyor frame a few feet from the tail pulley, the unit is secured by two heavy-duty safety cords.
The V-Plow features spring-loaded suspension to rise and fall with fluctuations in belt tension and travel.