History Of Belt Conveyors
Primitive belt conveyors have been used since the 19th century.
In 1892, Thomas Robins began a series of inventions which led to the development of a belt conveyor system used for carrying coal, ores and other products.
In 1901, Sandvik invented and started the production of steel conveyor belts.
In 1905 Richard Sutcliffe invented the first conveyor belts for use in coal mines which revolutionized the mining industry.
In 1913, Henry Ford introduced conveyor-belt assembly lines at Ford Motor Company’s Highland Park, Michigan factory.
In 1957, the B. F. Goodrich Company patented a conveyor belt that it went on to produce as a Turnover Conveyor Belt System. Incorporating a half-twist, it had the advantage over conventional belts of a longer life because it could expose all its surface area to wear and tear.
In 1970, Intralox, a Louisiana-based company, registered the first patent for all plastic, modular belting.
The conveyor belt consists of one or more layers of material. It is common for belts to have three layers: a top cover, a carcass and a bottom cover. The purpose of the carcass is to provide strength and shape. The carcass is often a woven or metal fabric having a warp & weft.
The warp refers to longitudinal cords which characteristics of resistance and elasticity define the running properties of the belt.
The weft represents the whole set of transversal cables allowing to the belt specific resistance against cuts, tears and impacts and at the same time high flexibility.
The most common carcass materials are steel, polyester, nylon, cotton and aramid. The covers are usually various rubber or plastic compounds specified by use of the belt.
Steel conveyor belts are used when high strength class is required. For example, the highest strength class conveyor belt installed is made of steel cords. This conveyor belt has a strength class of 10.000 N/mm and it operates at Chuquicamata mine, in Chile.
Polyester, nylon and cotton are popular with low strength classes. Aramid is used in the range 630 – 3500 N/mm. The advantages of using aramid are energy savings, enhanced lifetimes and improved productivity. As an example, a 2250 N/mm, 3400 m long underground belt installed at Baodian Coal Mine, part of in Yanzhou Coal Mining Company, China, was reported to provide energy savings of more than 15%.
Today there are different types of conveyor belts that have been created for conveying different kinds of material available in PVC and rubber materials. Material flowing over the belt may be weighed in transit using a beltweigher.
Belts with regularly spaced partitions, known as elevator belts, are used for transporting loose materials up steep inclines.
Belt Conveyors are used in self-unloading bulk freighters and in live bottom trucks. Belt conveyor technology is also used in conveyor transport such as moving sidewalks or escalators, as well as on many manufacturing assembly lines.
Department and Grocery stores often have belt conveyor at the check-out counter to move shopping items.
Ski slopes also use conveyor belts to transport skiers up the hill.
A belt conveyor consists of two or more pulleys or drums, with an endless loop of carrying medium that rotates about them. One or both pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler pulley.
There are two main industrial classes of belt conveyors; those in general material handling such as moving boxes along inside a factory and bulk material handling such as those used to transport large volumes of resources and materials, such as grain, salt, coal, ore, sand and more.
Belt conveyors are durable and reliable and used in automated distribution and warehousing.
In combination with a control panel and pallet handling equipment this allows for more efficient retail, wholesale, and manufacturing distribution. It is considered a labour-saving system that allows large volumes to move rapidly through a process, allowing companies to ship or receive higher volumes with smaller storage space and with less labour cost.
Rubber belt conveyors are commonly used to convey items with irregular bottom surfaces, small items that would fall in between rollers (e.g. a sushi conveyor bar), or bags of product that would sag between rollers (E.g. Salt or Flour).
Belt conveyors are generally similar in construction; and manufactured from Aluminium, Mild Steel or Stainless-Steel framework with rollers at either end of a flat bed. The belt is looped around each of the rollers and when one of the rollers is powered (by an electrical motor) the belt slides across the solid frame bed, moving the product.
Belt conveyors can now be manufactured with curved sections which use tapered rollers and curved belting to convey products around a corner. These conveyor systems are commonly used in sorting offices and airport baggage handling systems.
Belt conveyors are the most commonly used powered conveyors because they are the most versatile and the least expensive. Product is conveyed directly on the belt so both regular and irregular shaped objects, large or small, light and heavy, can be transported successfully. These conveyors should use only the highest quality premium belting products, which reduces belt stretch and results in less maintenance for tension adjustments. Belt conveyors can be used to transport product in a straight line or through changes in elevation or direction. In certain applications they can also be used for static accumulation or cartons.
In heavy use applications the conveyor bed which the belt is pulled over is replaced with rollers. The rollers allow weight to be conveyed as they reduce the amount of friction generated from the heavier loading on the belting.
Conveyors (in general)
The longest conveyor system is in Dubai Airport, and is a baggage handling system at 39 miles (63km) long.
It was installed by Siemens and commissioned in 2008, and is a combination of traditional belt conveyors and tray conveyors.
The world’s longest and second longest single belt conveyor is at Boddington Bauxite Mine in Western Australia, and is 19 miles (31km) long. This system feeds bauxite (aluminium ore) through the Darling Ranges to the Worsley Alumina refinery.
The longest single-belt international conveyor runs from Meghalaya in India to a cement factory at Chhatak Bangladesh.It is about 17 km long and conveys limestone and shale at 960 tons/hour, from the quarry in India to the cement factory (It comprises of a 7 km length in India and a 10 km length in Bangladesh).
The conveyor was engineered by AUMUND France and Larsen & Toubro and is actuated by three synchronized drive units for a total power of about 1.8 MW, supplied by ABB (two drives at the head end in Bangladesh and one drive at the tail end in India).
The conveyor belt was manufactured in 300-meter lengths on the Indian side and 500-meter lengths on the Bangladesh side, and was installed on-site. Dedicated vehicles were designed for the maintenance of the conveyor, which is always at a minimum height of 5 metres above the ground to avoid being flooded during monsoon periods.