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A Complete Guide to Bucket Elevator Maintenance

If proper preventive maintenance practices are not followed by the bucket elevators manufacturers, there will always be the consequence of the lack of dependability, increased costs,
safety problems, terrible housekeeping, and unhappy employees. There will also be unexpected downtime due to breakdowns which will also result in lost production and unhappy management.

Preventative maintenance of a bucket elevator system begins long before the unit is even commissioned. Some of the ongoing maintenance headaches could have been forestalled by sizing the elevator for future loads in good order, delineating quality components appropriate to the application, installing a complete control monitoring system, and providing adequate space and
access for maintenance personnel to get to the equipment.

Another area that requires attention is the commissioning and installation of the bucket elevator. Control monitoring devices must be wired in before start-up. Elevator casing must be installed straight and plumb. Head and boot pulleys must be perpendicular and plumb about each other.

For a proper elevation, inlets must have enough space for other materials straight into the elevator buckets or the feeding of grain. Fasteners must be tightened to the correct tension, especially bearing set-screws and pulley hubs. Bearings and gearboxes must be lubricated properly, and drive components adjusted. Most of these things must be verified several times during the commissioning process, so consult your owner's manual for the manufacturer's recommendations.

The third thing to remember is that the maintenance personnel must have adequate training to accomplish the procedures and must know what to do, how and when to do it. It's important that the entire maintenance division is doing the same thing the same way every time. Coherence is the key to an effective preventative maintenance program.

Lastly, management must think of preventive maintenance regarding 'relativity,' instead of a budget 'liability,' and make it a priority, or preventative maintenance will not happen. Put another way, which is more expensive, a fire extinguisher, or a fire truck?

Maintenance checklists recommended by bucket elevator manufacturers

It is important to take cognizance that the OSHA Standards for General Industry mandate regularly scheduled inspections of mechanical and safety control equipment and lubrication. The facility is required to maintain a certification record of each inspection.

Certification documents work best when used as checklists. These should be pre-printed forms for consistency and should use a separate list for each bucket elevator in your plant.

There must be a schedule for inspection, which has to be religiously followed. Depending on its utilization, the frequency of inspection may be anywhere from seasonal, to monthly or weekly.

Known problem areas may have to receive special treatment, such as a reducer known to walk on the head shaft, or a bearing known to run "hot." Some of the things on a proper checklist will require the unit to be shut down and must follow appropriate lock-out/tag-out procedures.

Safety first!

At the minimum, it is advisable to check the following items regularly:

BEARINGS: Examine for extreme heat, unusual noises, excessive shaft movement, tight fasteners and locking devices. Clean up and lubricate as recommended by the bearing manufacturer. Do not over grease!

PULLEYS: Check for tightness of pulleys on shafts, and that head shaft is level. Check alignment of pulleys in casings, and alignment of the head pulley to boot pulley. Pulleys must be plumb to each other in both directions.

Inspection of lagging is vital for wear, tightness, and cracks. The lift crown must be centred and adequate for proper belt tracking. Pulley hubs, discs, and check for edges is a must for cracking or other signs of stress or fatigue.

BELTING: Check for the stretch, damage and wear on both front and back sides and ends of belting. Check belt tracking on both pulleys, under both loaded and unloaded conditions. Check for loose fasteners or wear on belt splices.

BUCKETS: Check for condition of buckets, missing buckets, and tightness of screws. Look under operation to see if buckets are rubbing or banging against elevator casing.

TAKE-UPS AND TENSIONING DEVICES: Check for proper operation and adjustment.

CASINGS: Check for leaks, deterioration, and obstructions. Verify that casings have not shifted from a vertical position. Check inspection doors for tightness, dust sealing, and the presence of
safety grating.

HEAD AND BOOT SECTIONS: Check for wear and condition of lining materials. Periodically clean boot section to prevent infestation and cross contamination. Check inspection doors for tightness, dust sealing, and the presence of safety grating. Inspect head wiper.

MOTORS AND DRIVES: Check motor, reducer and drive components for proper operation, alignment, operating temperature, lubrication levels, and excessive vibration. Check fasteners for tightness, and seals for deterioration and leaks. If present, check backstops for proper operation.

Add oil or grease per the manufacturer's specifications, or change if necessary. Include jacking drives, if present, in these inspections.

CONTROLS, MONITORING DEVICES AND ELECTRICAL: Check lockouts, interlocks, ammeters and start/stop controls for proper operation. Check slowdown switches, alignment sensors, bearing heat sensors and alarms for proper operation and adjustment. Check bonding and grounding for continuity.

EXPLOSION VENTING: Check for proper function and obstructions. Check explosion suppression and fire extinguishing systems, if present.

ACCESS AND SAFETY EQUIPMENT: Check ladders, safety cages, handrails, handrail gates and platform grating for the safe condition, adherence to the OSHA standards. Any platforms without safe clearance around, and central access to, the elevator leg components must be modified as necessary.

STRUCTURAL: Check condition of support towers and bracing. Check and adjust guy-wire bracing as necessary. Check boot pits for cleanliness and water leaks. Check sump pumps and
drainage piping for condition and proper operation.

GENERAL CONDITION: Check condition of paint or galvanising. Inquire of operators of any known problems not already reported.

Modifying the checklists for the specifics of your operations is necessary. Deficiencies should be reported to management, prioritised for urgency and scheduled for repair or closer monitoring, depending on the situation.

Ultimately, here are few words about predictive maintenance. One of our national accounts has significantly increased their operational reliability by instituting a predictive maintenance program. They've been able to make massive cuts in spare parts inventories, and schedule component replacement work in advance, instead of in panic mode.

We suggest you give serious consideration to these measures:

THERMOGRAPHIC SCANNING: Infrared scanning reports actual operating temperatures, instead of a suspicion that a bearing, motor or gearbox is running "hot." It will also identify electrical devices like starters and switches running hot inside their enclosures, and can give you an idea how quickly something heats up, versus same equipment.

LUBRICATION ANALYSIS: Certainly cost effective for large gearboxes, gives warning of gear failure and allows replacement or repair of reducers before failure at critical times.

VIBRATION ANALYSIS: Identifies bearings, reducers, shafts and other moving objects with excessive "shake," and can often isolate the location of the problem device.

In addition to giving warning of impending failure, predictive maintenance can also reveal when something is not likely to fail. That knowledge will save money in replacement parts and worker hours. "If it ain't broke, why fix it?"/

Finally, for bucket elevator manufacturers, a good preventive maintenance and reliability program is a synergy of the right equipment, operated correctly, and regularly inspected and maintained by properly trained professional support personnel. 
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