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Troubleshooting on screw conveyor for waste or sludge management

Screw conveyor is a mechanically simple device that can move dry bulk materials at various speeds over straight distances typically up to about 100 feet. The components include the conveyor trough, inlet and discharge trough end bearings, hanger bearings, screw flight tips, the coupling shaft, the drive shaft, shaft holes, and the motor and so on. We take common troubleshooting as example and reference to users

Conveyor trough

Any of three problems can cause the conveyor trough to fail prematurely:
The trough material (typically steel) is too light for your conveyed material or conditions.
The screw has excessive deflection.
The screw flight tips are bent.
 
If the steel in your trough is too light, an abrasive material such as aggregate rock can wear holes in it. A caustic material can eat through the trough. Rust from a moist powder or humid operating conditions can also produce holes in the trough walls. A high-temperature material can damage the trough.
 
In these cases, you need to replace the damaged trough with one made of a heavier-gauge steel. Consider your conveyed material and operating conditions when selecting the gauge. If your material is abrasive, caustic, or moist, you can also consider lining the trough with plastic. Consult your screw conveyor manufacturer for help selecting a suitable trough material.
 

Inlet trough end bearing

The bearing at the inlet trough end can fail from one of these causes:
Material has gotten into the bearing.
The bearing has insufficient lubrication.
The screw has excessive deflection.
 
screw conveyor for waste
If the bearing is damaged because material has worked into it, the bearing’s seal has failed. This is more likely to occur when you convey a fine or abrasive material or convey with a high trough loading. To keep material out of the bearing, add a new seal to the bearing or upgrade the existing bearing. You can switch to an air-purged bearing that uses compressed air to blow material away from the seal, but this bearing is costly and requires a compressed-air supply.
 
You can also change from a conventional inboard bearing to an outboard style, so your material no longer contacts the bearing. If the bearing has been damaged by a lack of lubrication, replace the bearing and lubricate its seal more often.
 
Don’t wait until the bearing squeaks. Instead, follow the bearing manufacturer’s recommendation for lubrication frequency, and make this schedule part of your plant’s preventive maintenance procedures. If the screw has deflected beyond acceptable limits, the screw won’t be parallel to the trough and will oscillate as it rotates. This can wear out the bearing. Besides deflection sources discussed in the previous “Conveyor trough” section, other sources include accidentally dropping the screw before it’s installed or bumping into the conveyor with a forklift or other equipment.

After replacing the bearing and straightening and realigning the screw or replacing it, make sure the screw is straight before running the conveyor. To prevent future problems, check the screw alignment in the trough during your plant’s scheduled maintenance downtimes. More important, walk by the conveyor and listen to it every day or several times a day; small operating changes from deflection and other problems are usually audible; and the problems are easier to fix before they have a chance to damage your conveyor components

screw conveyor