This article is about a machine used in bulk material handling applications. For other uses of the term, see Stacker (disambiguation).
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Krupp coal stacker featuring tripper conveyor and non-slewing, luffing boom at RTCA Kestrel MineStacker at Garzweiler surface mine
A stacker is a large machine used in bulk material handling. Its function is to pile bulk material such as limestone, ores, coal and cereals onto a stockpile. A reclaimer can be used to recover the material.
Gold dredges in Alaska had a stacker that was a fixed part of the dredge. It carried over-size material to the tailings pile.
Stackers are nominally rated for capacity in tonnes per hour (tph). They normally travel on a rail between stockpiles in the stockyard. A stacker can usually move in at least two directions: horizontally along the rail and vertically by luffing (raising and lowering) its boom. Luffing of the boom minimises dust by reducing the distance that material such as coal needs to fall to the top of the stockpile. The boom is luffed upwards as the height of the stockpile increases. Some stackers can rotate the boom. This allows a single stacker to form two stockpiles, one on either side of the conveyor.
Stackers are used to stack in different patterns, such as cone stacking and chevron stacking. Stacking in a single cone tends to cause size segregation, with coarser material moving out towards the base. In raw cone ply stacking, additional cones are added next to the first cone. In chevron stacking, the stacker travels along the length of the stockpile adding layer upon layer of material.
Stackers and reclaimers were originally manually controlled, with no means of remote control. Modern machines are typically semi-automatic or fully automated, with parameters remotely set. The control system used is typically a programmable logic controller, with a human-machine interface for display, connected to a central control system.
Other than stacking, a stacker has three basic movements:
Luffing: This is vertical movement. Stackers use either a winch mechanism with metal wire, or hydraulic cylinders, generally two. Winch mechanisms are highly reliable compared to hydraulic actuators and remain widely used, particularly in large stackers.
Travelling: The stacker moves on a rail track, which may be broad or narrow gauge, enabling it to move around the stockyard as required. For this purpose, traction motors powered by direct current (DC) are connected by bevel gears to between 12 and 22 wheels. For manual control, all the controls are in a controller's cabin above the boom conveyor or boom. Modern stackers can be controlled remotely.
Slewing: This is rotation of the stacker around its central axis to align or place the stockpile where required. This works mostly by a slew pinion that rotates around a slew base. This type of gear assembly is called a sun and planet gear. The axles may be multiple and are driven by DC-powered axle motors which transmit the torque via bevel or helical gears.
The conveyor belts used in stackers may be made of fabric or metal wire, depending upon the material to be handled. They are driven by pulleys, which in turn are driven by DC motors. The motors and gear are coupled by fluid coupling.
Most stackers are electrically powered by way of a trailing cable. There are basically two types of cable trailing: power cord rotating drum (PCRD) and control cable rotating drum (CCRD). Pendulum adjustments are made to ensure the proper alignment of these cables while the stacker is travelling.
to ensure the proper alignment of these cables while the stacker is travelling. Look up stacker in Wiktionary, the free dictionary. Coal homogenization...
known primarily for its Lempel–Ziv–Stac lossless compression algorithm and Stacker disk compression utility for compressing data for storage. The original...
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that the Auto Stacker, along with the introduction of parking meters, would solve the town's parking problems. The eight-storey Auto Stacker was designed...
) A finals judge may not be a family member or the sport stacking instructor of the stacker. The competition's divided into 14 different age divisions...
seasons as head coach. Stacker served as an assistant coach in 2008–09 and 2009–10 with the Melbourne Tigers. In July 2010, Stacker was appointed head coach...
competition. Stacker won the 1969 premiership with Norths. Stacker's first job as a coach was in the lower grades for Parramatta. Stacker coached Parramatta...
Look up full stack in Wiktionary, the free dictionary. Full stack, full-stack or fullstack might refer to; Full stack, a player positioning strategy in...
Montell Samuel Daley (born 31 August 1994), known professionally as MoStack, is a British rapper and singer from Hornsey in North London. After releasing...
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moving logs. A fire two decades later destroyed most of the stacker buildings. Both the stacker and land upon which it sits are now owned by the city of...
BookStack is a free and open-source wiki software aimed for a simple, self-hosted, and easy-to-use platform. Based on Laravel, a PHP framework, BookStack...
cards in addition to a software driver. Known solutions include: Stacker XT/8 and Stacker AT/16 from Stac Electronics Expanz! and Expanz! Plus from InfoChip...
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In combinatorial optimization, the stacker crane problem is an optimization problem closely related to the traveling salesperson problem. Its input consists...
values to and from a push down stack. In the case of a hardware processor, a hardware stack is used. The use of a stack significantly reduces the required...
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