Optimize Your Belt-Conveyor Systems
Maintenance Technology | June 15, 2017
How well you treat these industry workhorses affects how long, how safely, and how cost-effectively they’ll run.
Belt-conveyor systems are used for a wide range of purposes. Regardless of the application, minimizing the cost per ton to move material and items without compromising safety, product integrity, and efficiency is accomplished by harnessing the best available technologies and maintenance practices.
Developing and implementing practical preventive-maintenance (PM) programs that have measurable results is key to reducing costs and maximizing your cost per ton. Continual daily upkeep is critical to extending conveyor belt and component life.
The entire system, including the belt, idlers, pulleys, frame, and accessories, should be included in the maintenance program. Routine system inspections, designed to encompass all aspects of each conveyor will help identify issues that, if not addressed and corrected, will cause catastrophic component failure, resulting in ancillary damage and potential safety hazards.
Prior to any inspection, perform appropriate lockout/tagout verification procedures. Ideally, the conveyor system is shut down and empty. This allows inspectors to check for damage to all components, including the belt and splice. Any damage noted during the inspection should be repaired as quickly as possible to prevent further degradation.
Keep in mind that the following checklists are general guides, and not all-inclusive. The key words are clean and operational. Pulleys or idlers that have material build-up on them will cause tracking problems. The same can be said for pulleys with uneven lagging wear. Belt-cleaning devices or systems, plows, and self-aligning idlers must be operational to perform their tasks. Belt damage, pulley damage, and tracking problems will result if these accessory components are not maintained.
Shut-Down-Conveyor-Inspection Checklist. A typical maintenance-inspection walk-through of a shut-down conveyor should include, but not be limited to, the following 19 items:
- Perform the lockout/tagout (LOTO) verification procedure.
- Identify safety hazards.
- Complete belt inspection.
- Inspect head pulley and/or drive pulley for damage, cleanliness, and worn lagging.
- Inspect for proper lubrication of bearings and mechanical devices.
- Inspect for the presence of material build-up and trapped material.
- Inspect skirting in the loading area for proper adjustment and condition.
- Inspect impact/slider bed or impact idler for damage and cleanliness.
- Inspect return- and carrying-side idlers for damage, cleanliness, and free-turning.
- Inspect all self-aligning idlers, both carrying- and return-side to ensure they are capable of operating (actuating from belt friction) and not tied off.
- Inspect for cleanliness of primary and secondary loading station.
- Inspect trippers to ensure they are clean and operational.
- Inspect structure/frame for integrity and alignment.
- Inspect tail-pulley condition.
- Inspect head-pulley cleaner to ensure it is operational.
- Inspect head, bend, and snub-pulley condition.
- Inspect the clean and operating take-up.
- Ensure plow (V-guide or angle) is operational.
- Ensure all bearings are clean and capable of operating.
Once inspection of the shut-down conveyor is completed, confirm that all personnel, tools, and equipment are clear of the system and accounted for to avoid injuries or damage to the equipment when it is restarted. Next, energize the system and let it run empty to ensure proper belt tracking. Perform another visual walk-through and listen carefully to make sure there are no unusual noises, which could indicate idler or bearing failure or rubbing of the belt against the conveyor structure. Be sure the belt is running reasonably well before introducing a load and conducting the next inspection. Note that empty and loaded conveyor systems may track differently. Furthermore, remember that any component with which the belt comes in contact will affect its tracking.
A typical maintenance-inspection walk-through of a loaded (running) conveyor system should include, but not be limited to, the following 13 items:
- Inspect for satisfactory tracking along the belt’s entire length.
- Inspect for and ensure there are no bearing noises.
- Inspect for primary and secondary loading-station spillage.
- Inspect carrying-side idlers to ensure they are turning freely.
- Inspect self-aligning carry idlers to ensure they are functioning (actuating from belt friction).
- Inspect for excess material spillage.
- Inspect head and/or drive pulley, snub, and bend pulleys to ensure they are running smoothly with no slippage.
- Inspect belt cleaners to ensure they are functioning.
- Inspect return idlers to ensure they are clean and turning freely.
- Inspect tail pulley to ensure that it is turning freely without product build-up or carryback.
- Inspect take-up pulley to ensure it is turning freely without bearing noise, is clean, and moving freely in the frame.
- Inspect for belt tracking, in general.
- Inspect plow (V-Guide or angle) to ensure it is operating properly.
Following completion and documentation of these inspections, a corrective-action plan should be implemented. Any safety concern must be addressed immediately, including, among other things, installation and/or repair of conveyor crossovers, safety-stop cables, failed holdbacks on incline conveyors, misalignment switches, motor guards, hand rails, and cleaning of walkways.
The importance of clean conveyor systems can’t be overstated. Cleanliness is a safety issue. Premature conveyor belt wear, idler and pulley failure, along with structural damage to the conveyor frame are all indicators of a system experiencing significant carry-back and fugitive-material contamination. Product build-up on return-side pulleys and idlers not only reflects a housekeeping issue, it can lead to belt-tracking problems and added stresses on the splice. If a belt isn’t clean on the return flight, any pulley that comes in contact with the belt’s carry side will accumulate product.
Material build-up on a belt and components doesn’t simply cause tracking problems. It could bring a system to a grinding halt, costing the operation countless dollars in lost material, downtime, clean-up, damage to the system, and, potentially, personal injuries. A clean conveyor system is not only a safer system, it can maximize your cost per ton.
Primary and secondary belt-cleaning systems at the discharge area and plows in front of the tail pulley are essential to reduce damage to the components. Sticky materials present a real challenge when it comes to preventing carryback. A well-engineered and maintained cleaning system to minimize carryback will reduce associated cost. Some variables to consider when designing and installing a cleaning system include the material to be conveyed, environmental and operational factors, and belt type and condition.
It’s a given in any plant: Safety should be the number one priority of all owner/operators and workers, and an integral part of the workplace culture. Zero is the only number acceptable for incidents and accidents. Safe habits take effort to develop, and are less likely to be broken when developed. Once a culture of safety is established in any organization, it will perpetuate itself.
Constantly pay attention to your work environment and those working around you. This situational awareness could prevent a possible accident before it happens and save you and the organization unwanted pain and expense. When it comes to conveyors, keep these basic safety tips in mind:
- Always perform proper lockout/tagout verification procedures.
- Use only trained and authorized maintenance and operating personnel.
- Keep clothing, fingers, hair, and other body parts away from moving conveyor parts.
- Don’t climb, step, sit, or ride on conveyors.
- Don’t overload conveyors.
- Don’t remove or alter conveyor guards or safety devices.
- Know the location and function of all stop/start controls and keep the locations free of obstructions.
- Confirm all personnel are clear of a conveyor before starting or restarting it.
- Keep areas around conveyors clean and clear of obstructions.
- Report all unsafe practices to a supervisor. MT
Information in this article was provided by Don Sublett of Motion Industries (Birmingham, AL). Sublett has worked in areas of conveyor-belt design and service since 1976 and is an active member of various professional associations in the field. For more information, visit MotionIndustries.com or see the Mi Hose & Belting video here.