A SYSTEMS FOCUS FOR MAXIMIZING CONVEYOR PRODUCTIVITY
By
Kevin Finnegan
Market Manager – Heavy Duty
Bill Hoogewind
Market Manager -- Belt Conveyor Products
Flexible Steel Lacing Company, Parramatta Group
A systems perspective -- combining belts, fasteners and cleaners -- best orchestrates conveyor performance at mine sites worldwide
Regardless of the mine’s location anywhere in the world, effective coal production requires a proper balance between belt conveyor motion and maintenance. It’s what keeps coal running smoothly and avoids periods of costly, unpredicted downtime.
What is a proper balance, and how can it be attained and maintained to maximize production? While there is no “one plan fits all” formula to work from, there are steps that can be taken to help achieve it. Achieving balance hinges on a sensible systems approach that applies to the belt, fasteners and cleaners operating together. Collectively, these components comprise a system, and their interaction needs to receive attention in their selection, installation and maintenance.
Even though no two mines are the same, the systems approach is one that works regardless of a mine’s location or conditions. Put simply, it is a perspective that can be practiced anywhere. It has become part of the training sessions, presentations and related sessions conducted by our company’s representatives on a worldwide basis. It is a concept that can be universally understood and applied.
What makes a good mechanical fastener/cleaner combination? A number of factors merit consideration. Proper component selection requires an understanding of the composition of fasteners, the cleaners and the belt itself. There are numerous fasteners, cleaner designs and types of blades to choose from.
Mechanical Fastener Selection
Belt splicing is among the most critical considerations for preventing surprise belt failures and keeping repair downtime to a minimum. Although vulcanized splicing is preferred in some locations, mechanical splicing continues to prove its value as a cost reducing, uptime increasing alternative.
Suitable mechanical fasteners come in a variety of shapes and sizes. Each is designed with a common purpose to help mines maintain top productivity. Different compositions and styled fasteners make selection an important overall consideration.
Proper selection requires some homework. Before a choice is made:
Determine the belt tension: Most conveyor belting has a mechanical fastener rating, and care should be taken to avoid operation beyond the manufacturers’ recommended ratings.
Measure belt thickness: Fastener size selection should correspond with belt thickness. If the fasteners are to be countersunk, measure the belt thickness after the belt cover has been removed.
Measure the diameter of the smallest pulley in the drive: Consider all of the pulleys over which the belt makes at least a 90° wrap.
Choose a fastener that is appropriate for the application: To maximize fastener life, fastener material must be matched to the application. Consider different compositions, climates and operating conditions, along with different styled fasteners. (See illustration 1) For example, “scalloped edge” fasteners with concave scalloped edges enable fastener plate ends to embed deeper into the belt, with less effort. This design profile enables belt cleaners to ramp up and over the plates without hard edge impact. This design both enhances cleaning efficiency and reduces the risk of damaging the belt, the splice or the cleaner.
Hinged or solid plate: Solid plate styles are preferred for longer life and to prevent sifting. Hinged fasteners are preferred on portable conveyors and on conveyors with smaller pulley diameters.
Belt Cleaner Selection
As with fastener selection, there are things to consider and determine in advance in the selection of precleaners, and secondary cleaners. These include:
Relief points: For proper system operation, the cleaner and splice need to interact with minimal impact. This interaction always creates kinetic energy, which needs to be stored and dissipated while keeping blades in contact with the belt. This is best accomplished through the use of multiple tensioning elements or relief points. These multiple tensioning elements are especially important for the higher speeds and loading rates encountered in mining conveyor systems. Generally, cleaners that incorporate more relief points allow the blade to gently ride over the fasteners and, after the fasteners have passed, to get back to the belt and resume cleaning.
Material path: In selecting precleaners, the length of the blade should cover just the material path of the conveyor. Typically this is two-thirds the width of the belt. It is unnecessary for the cleaning blade to extend to the belt edges where it accomplishes nothing more than rubbing against the belt. With the blade covering only the material path, the amount of differential wear between the center and the edges of the blade is reduced. Consequently, the blade maintains constant blade-to-belt contact for longer periods before the need for maintenance or tension adjustment.
Blade design: In high speed, high load conveyor applications, blade design and durability also deserve consideration for maintaining optimal blade tip tension and cleaner performance. Urethane precleaner blades should provide long life; enough strength to maintain good contact on the belt even with wet, sticky materials; and a sharp shearing edge to peel material off the belt. Faceted profile blade designs help preserve a sharp edge because they form a new shearing edge once wear reaches a new faceted blade section, enhancing cleaning efficiency throughout the life of the blade. On secondary cleaners, carbide inserted cleaning tips will best penetrate the most abusive, sticky wet carry back materials. Since carbide can be a brittle material, sandwich designs offer more protection than exposed tips against fracture from splice impact. In addition, use of a tungsten carbide blade mean long wear life with fewer tension adjustments. For applications still leaving water on the belt, another soft urethane secondary cleaner can be added to wipe the belt dry.
Cleaner Installation
Proper installation opens the door for proper performance. Naturally, this needs to be practiced by following manufacturers’ installation instructions. Every step must be followed, carefully and completely. An understanding of the basics will help assure they are followed to the letter.
Tangent Line of Force: With fastener/cleaner interaction in mind, knowledge of the tangent line of force will help determine where to position the cleaner pole for optimum system operation. A belt cleaner on the head pulley creates two interacting forces – the friction force of the belt coming around the pulley and the pressure force of the blade tensioned against the belt. The friction force acts tangent to the point of contact at the tip of the blade, and acts to try to suck the blade through.
Cleaner manufacturers set their coordinates so that this will not happen until after the blade has worn past its usable life, usually indicated by a wear line. If installation coordinates are not followed, the pole may be too far outside the tangent line of force and cause the blade to suck through prematurely.
Optimal tension: Tensioning is conceivably the most important influence on belt cleaning efficiency. Cleaners with proper tensioning ensure the blade and belt remain in constant contact without placing excessive pressure on the belt. In coal mining, most precleaners and many of the secondaries have either spring or pressurized tensioners. Both styles enhance system performance by allowing mechanical fasteners to pass easily under the blades and by continuously compensating for blade wear. Pressurized tensioners are more expensive but have the benefit of nearly zero maintenance. Spring tensioners are less costly but will require periodic maintenance during the life of the blade. As a rule, regular checks of belt/blade tension belong as part of monthly preventive maintenance. Visual inspection checks, enabled by spring tensioners or pressure gauges, provide an instant opportunity to react and remedy potential problems. On some cleaners, simple turns on an adjustment nut are all it takes to restore optimal tension.
Secondary Belt Cleaner Location: Generally speaking, most cleaners should be placed no closer than four inches from the transition point where the belt leaves the head pulley. This places the fastener beyond the head pulley and enables the belt to settle down and give a little when the cleaner blade pushes up against the fastener. Templates on some cleaners help users identify proper locations. Similarly, gauges for correct setting of the blade angle provide valuable guidance, especially on secondary cleaners. The proper angle of the blade against the belt is critical to how it will interact with both the belt and the splice and can greatly impact cleaning performance.
Addressing Mistracking
Certainly maintenance measures must be followed to assure effective, prolonged component performance. Minor problems if not remedied become big trouble. Perhaps the most frustrating is the problem of mistracking. How it is addressed will have a strong influence on how well and how long the components perform as a system.
Whether caused by shifting, something bumping into the conveyor or premature wear on one side, the belt sometimes will not properly track through the center of the conveyor structure. In its advanced stages this can become a major problem with the possibility of catastrophic, costly failures.
The use of pressure rollers provide a simple reliable solution for problem belts that continuously mistrack to one side. When applied on the return side of the belt, the angled rollers mounted in a fixed position address the problem by continuously funneling the belt into the correct path.
A different belt trainer is better suited when the belt wanders to either side. Most trainers are adaptive and utilize friction to steer the belt back to center. For severe problems or wet conditions, a trainer that relies on friction only may not be sufficient. For example, Flexco’s PT-Max high-performance belt trainer utilizes a “pivot and tilt” action that also alters the belt tension profile. By creating an asymmetrical belt tension, this device easily steers even the highest tensioned belts.
Proper Tools for Proper Performance
Belt repairs are inevitable. Addressing the problems with the right tools will reduce the possibility of recurring repairs and compounded problems affecting the entire system. In addition to making the repair more lasting, the right tools will also make the repair safer and more successful. A variety of portable tools are specifically designed for making repairs more time efficient and more effective. These include:
Belt cutters: Effective belt repairs start with straight, square cuts. Doing the job with a knife is inexact and potentially dangerous. Wider belts increase the margin for imprecision and error. Fastener performance is compromised and the compatibility of fasteners, belts and cleaners operating together suffers. Portable, lightweight belt cutters make straight square cuts easier and safer. Designed for belt thicknesses ranging up to 1” (12-25mm) and widths up to 84” (900-21230 mm), they help maximize splice life and minimize downtime.
Problems associated with mistracking – including
premature belt and splice wear, load spillage and fastener pullouts – are less likely to occur.
Skivers: Countersinking fasteners -- removing a strip of rubber top cover to lower fastener plates below the surface of the belt – addresses potential problems encountered between fasteners and cleaners. For lasting, effective results, it is not a job to be performed with in inexact and potentially dangerous hand-knife. Specially designed skivers ensure quick, safe and accurate top cover removal at various depths. It is also a cleaner and faster alternative to a router, since the skiver removes the top cover as one continuous strip.
Rivet drivers and sets: Portable power-driven belt repair tools also increase speed, precision and success of fastener installation. From a safety standpoint, they eliminate the possible dangers associated with manual hammering. They also simplify repairs in locations with tight clearances and result in uniform fastener installations. Collated rivet sets, designed for use with specific air-operated rivet drivers, also enhance the speed and uniformity of installations.
Conclusion
Conveyor belts, fasteners, cleaners, accessories and specialty tools have individual purposes and roles affecting overall performance. They can be evaluated and selected individually on the merits of their features and benefits. But for optimum performance they should be looked at and relied upon as part of a system, one designed and orchestrated for maximum output and prolonged operation.
Maximizing Conveyor Productivity
A SYSTEMS FOCUS FOR MAXIMIZING CONVEYOR PRODUCTIVITY
By
Kevin Finnegan
Market Manager – Heavy Duty
Bill Hoogewind
Market Manager -- Belt Conveyor Products
Flexible Steel Lacing Company, Parramatta Group
A systems perspective -- combining belts, fasteners and cleaners -- best orchestrates conveyor performance at mine sites worldwide
Regardless of the mine’s location anywhere in the world, effective coal production requires a proper balance between belt conveyor motion and maintenance. It’s what keeps coal running smoothly and avoids periods of costly, unpredicted downtime.
What is a proper balance, and how can it be attained and maintained to maximize production? While there is no “one plan fits all” formula to work from, there are steps that can be taken to help achieve it. Achieving balance hinges on a sensible systems approach that applies to the belt, fasteners and cleaners operating together. Collectively, these components comprise a system, and their interaction needs to receive attention in their selection, installation and maintenance.
Even though no two mines are the same, the systems approach is one that works regardless of a mine’s location or conditions. Put simply, it is a perspective that can be practiced anywhere. It has become part of the training sessions, presentations and related sessions conducted by our company’s representatives on a worldwide basis. It is a concept that can be universally understood and applied.
What makes a good mechanical fastener/cleaner combination? A number of factors merit consideration. Proper component selection requires an understanding of the composition of fasteners, the cleaners and the belt itself. There are numerous fasteners, cleaner designs and types of blades to choose from.
Mechanical Fastener Selection
Belt splicing is among the most critical considerations for preventing surprise belt failures and keeping repair downtime to a minimum. Although vulcanized splicing is preferred in some locations, mechanical splicing continues to prove its value as a cost reducing, uptime increasing alternative.
Suitable mechanical fasteners come in a variety of shapes and sizes. Each is designed with a common purpose to help mines maintain top productivity. Different compositions and styled fasteners make selection an important overall consideration.
Proper selection requires some homework. Before a choice is made:
Determine the belt tension: Most conveyor belting has a mechanical fastener rating, and care should be taken to avoid operation beyond the manufacturers’ recommended ratings.
Measure belt thickness: Fastener size selection should correspond with belt thickness. If the fasteners are to be countersunk, measure the belt thickness after the belt cover has been removed.
Measure the diameter of the smallest pulley in the drive: Consider all of the pulleys over which the belt makes at least a 90° wrap.
Choose a fastener that is appropriate for the application: To maximize fastener life, fastener material must be matched to the application. Consider different compositions, climates and operating conditions, along with different styled fasteners. (See illustration 1) For example, “scalloped edge” fasteners with concave scalloped edges enable fastener plate ends to embed deeper into the belt, with less effort. This design profile enables belt cleaners to ramp up and over the plates without hard edge impact. This design both enhances cleaning efficiency and reduces the risk of damaging the belt, the splice or the cleaner.
Hinged or solid plate: Solid plate styles are preferred for longer life and to prevent sifting. Hinged fasteners are preferred on portable conveyors and on conveyors with smaller pulley diameters.
Belt Cleaner Selection
As with fastener selection, there are things to consider and determine in advance in the selection of precleaners, and secondary cleaners. These include:
Relief points: For proper system operation, the cleaner and splice need to interact with minimal impact. This interaction always creates kinetic energy, which needs to be stored and dissipated while keeping blades in contact with the belt. This is best accomplished through the use of multiple tensioning elements or relief points. These multiple tensioning elements are especially important for the higher speeds and loading rates encountered in mining conveyor systems. Generally, cleaners that incorporate more relief points allow the blade to gently ride over the fasteners and, after the fasteners have passed, to get back to the belt and resume cleaning.
Material path: In selecting precleaners, the length of the blade should cover just the material path of the conveyor. Typically this is two-thirds the width of the belt. It is unnecessary for the cleaning blade to extend to the belt edges where it accomplishes nothing more than rubbing against the belt. With the blade covering only the material path, the amount of differential wear between the center and the edges of the blade is reduced. Consequently, the blade maintains constant blade-to-belt contact for longer periods before the need for maintenance or tension adjustment.
Blade design: In high speed, high load conveyor applications, blade design and durability also deserve consideration for maintaining optimal blade tip tension and cleaner performance. Urethane precleaner blades should provide long life; enough strength to maintain good contact on the belt even with wet, sticky materials; and a sharp shearing edge to peel material off the belt. Faceted profile blade designs help preserve a sharp edge because they form a new shearing edge once wear reaches a new faceted blade section, enhancing cleaning efficiency throughout the life of the blade. On secondary cleaners, carbide inserted cleaning tips will best penetrate the most abusive, sticky wet carry back materials. Since carbide can be a brittle material, sandwich designs offer more protection than exposed tips against fracture from splice impact. In addition, use of a tungsten carbide blade mean long wear life with fewer tension adjustments. For applications still leaving water on the belt, another soft urethane secondary cleaner can be added to wipe the belt dry.
Cleaner Installation
Proper installation opens the door for proper performance. Naturally, this needs to be practiced by following manufacturers’ installation instructions. Every step must be followed, carefully and completely. An understanding of the basics will help assure they are followed to the letter.
Tangent Line of Force: With fastener/cleaner interaction in mind, knowledge of the tangent line of force will help determine where to position the cleaner pole for optimum system operation. A belt cleaner on the head pulley creates two interacting forces – the friction force of the belt coming around the pulley and the pressure force of the blade tensioned against the belt. The friction force acts tangent to the point of contact at the tip of the blade, and acts to try to suck the blade through.
Cleaner manufacturers set their coordinates so that this will not happen until after the blade has worn past its usable life, usually indicated by a wear line. If installation coordinates are not followed, the pole may be too far outside the tangent line of force and cause the blade to suck through prematurely.
Optimal tension: Tensioning is conceivably the most important influence on belt cleaning efficiency. Cleaners with proper tensioning ensure the blade and belt remain in constant contact without placing excessive pressure on the belt. In coal mining, most precleaners and many of the secondaries have either spring or pressurized tensioners. Both styles enhance system performance by allowing mechanical fasteners to pass easily under the blades and by continuously compensating for blade wear. Pressurized tensioners are more expensive but have the benefit of nearly zero maintenance. Spring tensioners are less costly but will require periodic maintenance during the life of the blade. As a rule, regular checks of belt/blade tension belong as part of monthly preventive maintenance. Visual inspection checks, enabled by spring tensioners or pressure gauges, provide an instant opportunity to react and remedy potential problems. On some cleaners, simple turns on an adjustment nut are all it takes to restore optimal tension.
Secondary Belt Cleaner Location: Generally speaking, most cleaners should be placed no closer than four inches from the transition point where the belt leaves the head pulley. This places the fastener beyond the head pulley and enables the belt to settle down and give a little when the cleaner blade pushes up against the fastener. Templates on some cleaners help users identify proper locations. Similarly, gauges for correct setting of the blade angle provide valuable guidance, especially on secondary cleaners. The proper angle of the blade against the belt is critical to how it will interact with both the belt and the splice and can greatly impact cleaning performance.
Addressing Mistracking
Certainly maintenance measures must be followed to assure effective, prolonged component performance. Minor problems if not remedied become big trouble. Perhaps the most frustrating is the problem of mistracking. How it is addressed will have a strong influence on how well and how long the components perform as a system.
Whether caused by shifting, something bumping into the conveyor or premature wear on one side, the belt sometimes will not properly track through the center of the conveyor structure. In its advanced stages this can become a major problem with the possibility of catastrophic, costly failures.
The use of pressure rollers provide a simple reliable solution for problem belts that continuously mistrack to one side. When applied on the return side of the belt, the angled rollers mounted in a fixed position address the problem by continuously funneling the belt into the correct path.
A different belt trainer is better suited when the belt wanders to either side. Most trainers are adaptive and utilize friction to steer the belt back to center. For severe problems or wet conditions, a trainer that relies on friction only may not be sufficient. For example, Flexco’s PT-Max high-performance belt trainer utilizes a “pivot and tilt” action that also alters the belt tension profile. By creating an asymmetrical belt tension, this device easily steers even the highest tensioned belts.
Proper Tools for Proper Performance
Belt repairs are inevitable. Addressing the problems with the right tools will reduce the possibility of recurring repairs and compounded problems affecting the entire system. In addition to making the repair more lasting, the right tools will also make the repair safer and more successful. A variety of portable tools are specifically designed for making repairs more time efficient and more effective. These include:
Belt cutters: Effective belt repairs start with straight, square cuts. Doing the job with a knife is inexact and potentially dangerous. Wider belts increase the margin for imprecision and error. Fastener performance is compromised and the compatibility of fasteners, belts and cleaners operating together suffers. Portable, lightweight belt cutters make straight square cuts easier and safer. Designed for belt thicknesses ranging up to 1” (12-25mm) and widths up to 84” (900-21230 mm), they help maximize splice life and minimize downtime.
Problems associated with mistracking – including
premature belt and splice wear, load spillage and fastener pullouts – are less likely to occur.
Skivers: Countersinking fasteners -- removing a strip of rubber top cover to lower fastener plates below the surface of the belt – addresses potential problems encountered between fasteners and cleaners. For lasting, effective results, it is not a job to be performed with in inexact and potentially dangerous hand-knife. Specially designed skivers ensure quick, safe and accurate top cover removal at various depths. It is also a cleaner and faster alternative to a router, since the skiver removes the top cover as one continuous strip.
Rivet drivers and sets: Portable power-driven belt repair tools also increase speed, precision and success of fastener installation. From a safety standpoint, they eliminate the possible dangers associated with manual hammering. They also simplify repairs in locations with tight clearances and result in uniform fastener installations. Collated rivet sets, designed for use with specific air-operated rivet drivers, also enhance the speed and uniformity of installations.
Conclusion
Conveyor belts, fasteners, cleaners, accessories and specialty tools have individual purposes and roles affecting overall performance. They can be evaluated and selected individually on the merits of their features and benefits. But for optimum performance they should be looked at and relied upon as part of a system, one designed and orchestrated for maximum output and prolonged operation.
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