The new automatic pneumatic tensioning system for conveyor belt cleaners from US bulk materials handling solutions provider Martin Engineering will be available in South Africa through its office in Mpumalanga in the second half of this year.
The solution will extend the service life of the cleaner and the conveyor belt.
The Automated Blade System (ABS) delivers precise monitoring and tensioning throughout the cleaning blade’s life, reducing the labour typically required to maintain the most effective blade pressure. Equipped with sensors to confirm that the belt is loaded and running, the system automatically backs the blade away during stoppages or when the conveyor is running empty, simultaneously reducing unnecessary wear on the belt and the cleaner. The result is a consistently correct blade tension, with reduced power demand on start-up; all managed without operator intervention.
“Mechanical designs work well as long as they are properly adjusted but, in many cases, require periodic attention from maintenance crews as the cleaning blade wears down. Also, some operators will loosen a mechanical tensioner to reduce drag at start-up, which decreases the belt cleaner’s performance if it is not correctly retensioned afterward,” explains Martin Engineering product development engineer Andrew Timmerman.
Effective conveyor belt cleaning forms a critical element of safe, productive conveying for several reasons, says the company. Most importantly, it limits carryback – when material sticks to the belt after the main load is discharged, resulting in the loss of otherwise valuable material spilled along the length of the conveyor. Carryback can also affect belt tracking, causing the belt to deviate from its intended path, contributing to damage of the belt and other components.
Further, the abrasive nature of fine particles shaken off of an uncleaned belt can significantly shorten the service life of rollers, pulleys and idlers. They can also contribute to dust fall-out at mining operations, becoming a potential health hazard when inhaled by personnel, or becoming a safety risk as dust can fuel a fire or result in an explosion, depending on the material being conveyed. A conveyor belt fire of any size is a significant issue, stresses Martin Engineering, because the belt or its contents may be destroyed and the length and movement of the belt can spread a fire a great distance in a short time.
The company highlights that fugitive material requires maintenance personnel for clean-up, at the expense of valuable work hours, and places staff in close proximity to a moving conveyor, which always carries a potential safety risk. Controlling fugitive material is, thus, a critical element in plant safety.
Following six months of testing, the company’s ABS went into operation for the first time in February this year at a cement-manufacturing plant in Illinois, in the US. The company has received positive feedback from the plant and is eager to expand the tensioner’s distribution through its global supplier network.
Martin Engineering is confident that the ABS’s safe-to-service (STS) feature will generate significant interest in mining applications. Servicing or replacing conventional belt cleaners typically requires accessing the frame at both sides – a time-consuming and potentially hazardous activity. The STS feature addresses the risk of staff reaching over or under the belt, as it requires one worker to access the frame from only one side, reducing the time required to perform maintenance or replacement work.
“With mines, globally, constantly seeking ways to improve safety and productivity while reducing costs, the STS design [also] extends equipment life,” says the company.
The ABS can also be supplied for locations with or without a municipal power source. On sites with electricity, the company has a 120 V/240 V alternating current system, which is designed to power its 24 V compressor. For operations able to supply power to the system from an electricity grid and generate compressed air to drive the head pulley, the system can be designed so that it simply handles the engagement and disengagement of the cleaner blade.
For locations lacking access to municipal power, the self-contained version uses the moving conveyor to generate its own electricity, which powers a small 24 V direct current air-compressor to constantly maintain optimum blade pressure. Built around the company’s patented Martin Roll Generator, the new self-powered version includes a proprietary energy storage system, equipped with lead acid batteries, developed specifically for this application. Thereby, the system can produce ample power to drive the compressor, which maintains pressure in the reservoir to retension the cleaner.
The generator can produce as much as 40 W of power at maximum speed, sufficient to run components such as weigh scales, proximity switches, moisture sensors, solenoids and relays, as well as timers, lights and safety devices. Wireless communication can be used to transmit directly to a central controller, enabling operators to cost effectively access data on the ABS that has not been readily available in the past.
Batteries are also included in the system’s standard design to power high-current draw devices, such as compressors or actuators, which require more than 40 W. “The compressor needs to run only for a brief period to maintain pressure in the reservoir, which . . . is then regulated to keep the cleaners at the proper tension. The batteries recharge during the normal running of the belt and are quickly ready to cycle again as needed,” explains Timmerman.