Take preventative action, and understand possible causes.
Edited by Mark S. Kuhar
Conveyor belts are both the most important and most expensive conveyor component. According to the Australian Bulk Handling Review, the value of iron ore is currently estimated at US$120 or A$160 per tonne.
Therefore, a conveyor capable of moving 5,000 tonnes per hour can suffer A$800,000 of lost production every hour if a conveyor belt requires replacement due to avoidable damage or wear.
To help you reduce damage to your conveyor belt and the potential costly exercise of a belt replacement, DYNA Engineering recommends four ways to reduce belt damage.
1. Appropriate Belt Type – The type of material and the environment of your conveying will greatly affect the service life of your conveyor belt as the specification of belt will wear more quickly if it isn’t suited to the application. There are multiple grades of rubber conveyor belting, each of which have special properties that ensure their suitability.
For example, Grade A is an abrasion-resistant rubber belt, which is used to convey rough or abrasive material. If your conveyor requires the use of Grade A, but you instead installed a general-purpose N grade rubber belt you would find that the N grade belt would be more susceptible to wear from the abrasive material. Thus, the service life would be reduced and the belt will require replacement sooner than a Grade A belt.
2. Cleaning & Maintenance – Carryback (or material that remains adhered to the underside of the conveyor belt) can cause increased wear on the surface of the belt if it gets stuck to other conveyor components. The wear that carryback causes can be greater if the layer of material is left to thicken or harden over time.
To reduce carryback and the associated wear on the conveyor belt, it’s important to keep the belt as clean as possible during operation. Cleaning of the belt can be effectively achieved with the appropriate belt scraper, v-plows, spray bars and brush cleaners.
3. Impact Protection – When large and heavy material impacts the conveyor belt, especially at the impact zones, damage can occur to the belt. Impact damage can include tears in the belt or, if the velocity of the impacting material is high enough, the objects can puncture holes in the belt.
Two effective methods of absorbing impact forces is the installation of impact idlers or impact beds, which are particularly important at the loading point and transfer points.
Impact beds are used in place of idlers when the impact force or velocity are especially high. They close the gap inherent in impact idler rollers designs, and thus provide more support to the belt where required which can increase the belt’s service life.
4. Prevention of Mistracking – The conveyor belt can be prone to mistracking for various reasons, examples include worn conveyor pulley and material build up. When the belt mistracks, it is prone to damage and additional wear, especially along the edge of the belt where unwanted contact with surrounding structure may occur.
Installation of tracking rollers can be an effective additional of helping to prevent belt mis-tracking and the damage that can consequently occur.
DYNA-TRAC tracking rollers are an ideal option as they are self-aligning and self-adjusting, which ensures the belt maintains central alignment.
Common Causes of Conveyor Belt Damage
It is also important to maintain conveyor belts correctly and minimise any potential stoppages or damage to maintain the maximum up time and service life. DYNA Engineering notes five ways your belts might sustain damage.
1. Abrasive Material – Materials being processed along the belt will over time wear out the belt surface. This is especially true for abrasive materials, such as iron ore, or where the conveyors are operating at high speed, high capacity and process rocky material.
These abrasive materials can also become misplaced in other areas, such as underneath or along the edges of the belt, causing preventable belt wear.
Suggested solution: correct belt type. Having the correct type of belting for the materials being carried can reduce the rate or risk of damage to the belt. For example, Grade A belts are Abrasion Resistant, therefore are longer lasting than General Purpose (Grade M&N) belts.
There are many different grades of textile/rubber belts, designed to suit different types of material.
Suggested solution: conveyor skirting. Conveyor skirting is a system that creates an effective seal between the conveyor structure and the belt. Conveyor skirting prevents stray material from becoming lodged between the belt and conveyor structure, that can cause abrasive wear and grooving on the belt.
DYNA Engineering offers the Flexiseal Conveyor Skirting, which has been designed to create an effective seal between the conveyor structure and the conveyor belt, making it a superior option to conventional conveyor skirting.
2. Carryback Build-up – Carryback can cause a range of problems for many conveyor components. In terms of belt damage, carryback reduces the efficiency and service life of the belt – especially if the layer of carryback thickens or hardens over time.
Furthermore, when carryback is stuck to other conveyor components, it can be consistently contacting the belt and effectively wearing the belt away.
Suggested solution: proper conveyor belt cleaning solutions. There are many different types of belt cleaning solutions on offer depending on a variety of factors. Essentially, their main purpose is to eliminate carryback on the belt; maintaining a clean belt free from potentially costly issues caused by carryback.
DYNA Engineering’s comprehensive range of belt cleaners can meet any belt cleaning requirement:
- Air Knives
- Belt Scrapers
- Brush Cleaners
- Spray Bars
3. Material Impact Damage – Large and bulky material can cause damage to conveyor rollers, frames and belt. When the material lumps and become large or excessive, rollers become less effective.
When the lumps impact between the rollers, the belt is stretched to absorb the forces and causes stress. Over time, the impact can disfigure the belt.
The impact zone (where the material is dropped off the end of one conveyor onto another) is another area that is prone to extensive belt damage.
Suggested solution: impact rollers and idlers. Impact rollers and idlers are a decent solution to reduce the impact forces of materials, in turn reducing the rate of wear on your belt.
Impact rollers and idlers, compared to standard rollers/idlers, protect the belt from material impact damage by absorbing and transferring the impact forces.
Suggested solution: impact beds. Impact beds are used in place of impact rollers and idlers. They are usually installed under the belt and the impact zones and absorb the impact forces from falling material.
Impact beds offer more support for the conveyor belt and closes the gaps left by impact rollers.
4. Belt Mistracking – It is a common issue that can be caused by a large range of factors, such as material build up (carryback), roller/idler condition, pulley lagging condition or type and even the condition of the belt itself.
Suggested solution: tracking rollers. DYNA Engineering’s DYNA-TRAC tracking rollers perform consistent corrections to keep the belt running smoothly, aligned and centred. They are a low-cost and low-maintenance solution to belt mistracking and can be easily installed.
DYNA-TRAC tracking rollers have many key features that aid in belt tracking.
5. Belt Cleaner – A belt cleaner system that is either not suitable for your application or improperly installed can become a source of damage to your conveyor belt. For example, belt scrapers are productive cleaners but a worn carbide-tipped blade can tear the belt.
Suggested solution: correct blade type on scrapers. It is important that the correct type of scraper blade is used on your application, whether it be polyurethane or carbide, or something more exclusive.
Suggested solution: ongoing maintenance. Regular maintenance is the most effective way to prevent conveyor belt damage for any reason. Maintenance will identify any potential risks or problems, areas for improvement, and worn or failed components. This includes worn scraper blades that pose as a physical damage risk to the conveyor belt.
Information for this article courtesy of DYNA Engineering, www.dynaeng.com.au.