Screw conveyor

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Archimedes' screw Archimedes-screw one-screw-threads with-ball 3D-view animated small.gif
Archimedes' screw
Centreless screw conveyor CentrelessConveyor.JPG
Centreless screw conveyor

A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw blade, called a "flighting", usually within a tube, to move liquid or granular materials. They are used in many bulk handling industries. Screw conveyors in modern industry are often used horizontally or at a slight incline as an efficient way to move semi-solid materials, including food waste, wood chips, aggregates, cereal grains, animal feed, boiler ash, meat, bone meal, municipal solid waste, and many others. The first type of screw conveyor was the Archimedes' screw, used since ancient times to pump irrigation water. [1]

Contents

They usually consist of a trough or tube containing either a spiral blade coiled around a shaft, driven at one end and held at the other, or a "shaftless spiral", driven at one end and free at the other. The rate of volume transfer is proportional to the rotation rate of the shaft. In industrial control applications, the device is often used as a variable rate feeder by varying the rotation rate of the shaft to deliver a measured rate or quantity of material into a process. [2]

Screw conveyors can be operated with the flow of material inclined upward. When space allows, this is a very economical method of elevating and conveying. As the angle of inclination increases, the capacity of a given unit rapidly decreases.

The rotating part of the conveyor is sometimes called simply an auger.

In agriculture

This combine harvester uses a screw conveyor within the tube to discharge grain into the trailer alongside Combine-harvesting-corn.jpg
This combine harvester uses a screw conveyor within the tube to discharge grain into the trailer alongside
A screw conveyor moving grape stems away from wine grapes after they've been destemmed. In vertical deployment, the linear force is upwards, but portions of the circular motion point downward, at a slight gradient. Function depends on the material transported resisting downward flow.

The "grain auger" is used in agriculture to move grain from trucks, grain carts, or grain trailers into grain storage bins (from where it is later removed by gravity chutes at the bottom). A grain auger may be powered by an electric motor; a tractor, through the power take-off; or sometimes an internal combustion engine mounted on the auger. The helical rotates inside a long metal tube, moving the grain upwards. On the lower end, a hopper receives grain from the truck or grain cart. A chute on the upper end guides the grain into the destination location. [2]

First Grain Auger invented in 1945 in Toronto, Canada First Grain Auger circa 1945.png
First Grain Auger invented in 1945 in Toronto, Canada

The modern grain auger of today's farming communities was invented by Peter Pakosh. His grain mover employed a screw-type auger with a minimum of moving parts, a totally new application for this specific use. At Massey Harris (later Massey Ferguson), young Pakosh approached the design department in the 1940s with his auger idea, but was scolded and told that his idea was unimaginable and that once the auger aged and bent that the metal on metal would, according to a head Massey designer, "start fires all across Canada". [3] Pakosh, however, went on to design and build a first prototype auger in 1945, and 8 years later start selling tens of thousands under the 'Versatile' name, making it the standard for modern grain augers.

A specialized form of grain auger is used to transfer grain into a seed drill and is usually quite a lot smaller in both length and diameter than the augers used to transfer grain to or from a truck, grain cart or bin. This type of auger is known as a "drill fill". Grain augers with a small diameter, regardless of the use they are put to, are often called "pencil augers".

Centerless augers are particularly popular in industrial animal farming facilities, where the primary application is distributing animal feed from a central storage location to individual or group feeding devices. The flexible nature of the auger wire allows feed or other materials to change elevation and move at angles. The first centerless auger was patented by Eldon Hostetler and Chore-Time Equipment in the context of this application. [4] [5]

Other uses

Various other applications of the screw or auger conveyor include its use in snowblowers, to move snow towards an impeller, where it is thrown into the discharge chute. Combine harvesters use both enclosed and open augers to move the unthreshed crop into the threshing mechanism and to move the grain into and out of the machine's hopper. Ice resurfacers use augers to remove loose ice particles from the surface of the ice. An auger is also a central component of an injection molding machine. An auger is used in some rubbish compactors to push the rubbish into a lowered plate at one end for compaction.

Augers are also present in food processing. They are a tool of choice in powder processing when it comes to conveyor does precisely bulk solids (powders, pellets...). [6] In a conventional meat grinder, chunks of meat are led by the auger through a spinning blade and a holed plate. This method emulsifies the fat in beef to soften hamburger patties and is also used to produce a wide variety of sausages and loaves. Augers are also used to force food products through dies to produce pellets. These are then processed further to produce products such as bran flakes.

Augers are also used in oil fields as a method of transporting rock cuttings away from the shakers to skips. Augers are also used in some types of pellet stoves and barbecue grills, to move fuel from a storage hopper into the firebox in a controlled manner. Augers are often used in machining, wherein the machine tools may include an auger to direct the swarf (scrap metal or plastic) away from the workpiece.

Screw conveyors can also be found in wastewater treatment plants to evacuate solid waste from the treatment process.

The amphibious infantry fighting vehicle BMP-3 uses an auger-type propulsion unit in water.

Olds elevator

The Olds elevator is a variant of a screw conveyor developed by Australian engineer Peter Olds in 2002. [7] [8] Rather than rotate a central screw blade, a stationary screw is contained within a rotating casing that scoops surrounding material into its base. [9] Following similar principles to the conventional screw conveyor, the Olds elevator can lift bulk materials efficiently. Since its invention, it has been assessed as a viable system for industrial uses by a number of academics. [10]

See also

Related Research Articles

<span class="mw-page-title-main">Archimedes' screw</span> Water pumping mechanism

The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest hydraulic machines named after Greek mathematician Archimedes who first described it around 234 BC, although the device had been used in Ancient Egypt. It is a reversible hydraulic machine, and there are several examples of Archimedes screw installations where the screw can operate at different times as either pump or generator, depending on needs for power and watercourse flow.

<span class="mw-page-title-main">Drill bit</span> Type of cutting tool

A drill bit is a cutting tool used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. In order to create holes drill bits are usually attached to a drill, which powers them to cut through the workpiece, typically by rotation. The drill will grasp the upper end of a bit called the shank in the chuck.

<span class="mw-page-title-main">Angle of repose</span> Steepest angle at which granular materials can be piled before slumping

The angle of repose, or critical angle of repose, of a granular material is the steepest angle of descent or dip relative to the horizontal plane on which the material can be piled without slumping. At this angle, the material on the slope face is on the verge of sliding. The angle of repose can range from 0° to 90°. The morphology of the material affects the angle of repose; smooth, rounded sand grains cannot be piled as steeply as can rough, interlocking sands. The angle of repose can also be affected by additions of solvents. If a small amount of water is able to bridge the gaps between particles, electrostatic attraction of the water to mineral surfaces increases the angle of repose, and related quantities such as the soil strength.

<span class="mw-page-title-main">Mixing (process engineering)</span> Process of mechanically stirring a heterogeneous mixture to homogenize it

In industrial process engineering, mixing is a unit operation that involves manipulation of a heterogeneous physical system with the intent to make it more homogeneous. Familiar examples include pumping of the water in a swimming pool to homogenize the water temperature, and the stirring of pancake batter to eliminate lumps (deagglomeration).

<span class="mw-page-title-main">Extrusion</span> Process of pushing material through a die to create long symmetrical-shaped objects

Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex cross-sections; and to work materials that are brittle, because the material encounters only compressive and shear stresses. It also creates excellent surface finish and gives considerable freedom of form in the design process.

<span class="mw-page-title-main">Mill (grinding)</span> Device that breaks solid materials into smaller pieces by grinding, crushing, or cutting

A mill is a device, often a structure, machine or kitchen appliance, that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such comminution is an important unit operation in many processes. There are many different types of mills and many types of materials processed in them. Historically mills were powered by hand or by animals, working animal, wind (windmill) or water (watermill). In modern era, they are usually powered by electricity.

<span class="mw-page-title-main">Bulk material handling</span>

Bulk material handling is an engineering field that is centered on the design of equipment used for the handling of dry materials. Bulk materials are those dry materials which are powdery, granular or lumpy in nature, and are stored in heaps. Examples of bulk materials are minerals, ores, coal, cereals, woodchips, sand, gravel, clay, cement, ash, salt, chemicals, grain, sugar, flour and stone in loose bulk form. It can also relate to the handling of mixed wastes. Bulk material handling is an essential part of all industries that process bulk ingredients, including: food, beverage, confectionery, pet food, animal feed, tobacco, chemical, agricultural, polymer, plastic, rubber, ceramic, electronics, metals, minerals, paint, paper, textiles and more.

<span class="mw-page-title-main">Silo</span> Structure for storing crops

A silo is a structure for storing bulk materials.

<span class="mw-page-title-main">Variable rate feeder</span>

A variable rate feeder is a piece of industrial control equipment used to deliver solid material at a known rate into some process.

<span class="mw-page-title-main">Feed mixer</span>

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<span class="mw-page-title-main">Rotary feeder</span>

Rotary feeders, also known as rotary airlocks or rotary valves, are commonly used in industrial and agricultural applications as a component in a bulk or specialty material handling system. Rotary feeders are primarily used for discharge of bulk solid material from hoppers/bins, receivers, and cyclones into a pressure or vacuum-driven pneumatic conveying system. Components of a rotary feeder include a rotor shaft, housing, head plates, and packing seals and bearings. Rotors have large vanes cast or welded on and are typically driven by small internal combustion engines or electric motors.

<span class="mw-page-title-main">Conveyor system</span> Equipment used for conveying materials

A conveyor system is a common piece of mechanical handling equipment that moves materials from one location to another. Conveyors are especially useful in applications involving the transport of heavy or bulky materials. Conveyor systems allow quick and efficient transport for a wide variety of materials, which make them very popular in the material handling and packaging industries. They also have popular consumer applications, as they are often found in supermarkets and airports, constituting the final leg of item/ bag delivery to customers. Many kinds of conveying systems are available and are used according to the various needs of different industries. There are chain conveyors as well. Chain conveyors consist of enclosed tracks, I-Beam, towline, power & free, and hand pushed trolleys.

<span class="mw-page-title-main">Concrete plant</span> Equipment that combines various ingredients to form concrete

A concrete plant, also known as a batch plant or batching plant or a concrete batching plant, is equipment that combines various ingredients to form concrete. Some of these inputs include water, air, admixtures, sand, aggregate, fly ash, silica fume, slag, and cement. A concrete plant can have a variety of parts and accessories, including: mixers, cement batchers, aggregate batchers, conveyors, radial stackers, aggregate bins, cement bins, heaters, chillers, cement silos, batch plant controls, and dust collectors.

<span class="mw-page-title-main">Mechanical stoker</span>

A mechanical stoker is a mechanical system that feeds solid fuel like coal, coke or anthracite into the furnace of a steam boiler. They are common on steam locomotives after 1900 and are also used on ships and power stations. Known now as a spreader stoker they remain in use today especially in furnaces fueled by wood pellets or refuse.

In manufacturing, threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element. There are many methods of generating threads, including subtractive methods ; deformative or transformative methods ; additive methods ; or combinations thereof.

<span class="mw-page-title-main">Granulation</span> Forming grains or granules from a powdery or solid substance

Granulation is the process of forming grains or granules from a powdery or solid substance, producing a granular material. It is applied in several technological processes in the chemical and pharmaceutical industries. Typically, granulation involves agglomeration of fine particles into larger granules, typically of size range between 0.2 and 4.0 mm depending on their subsequent use. Less commonly, it involves shredding or grinding solid material into finer granules or pellets.

High-density solids pumps are hydrostatically operating machines which displace the medium being pumped and thus create a flow.

Pellet heating is a heating system in which wood pellets are combusted. Other pelletized fuels such as straw pellets are used occasionally. Today's central heating system which run on wood pellets as a renewable energy source are comparable in operation and maintenance of oil and gas heating systems.

<span class="mw-page-title-main">Pellet boiler</span> Heating system

A pellet boiler is a heating system that burns wood pellets. Pellet boilers are used in central heating systems for heat requirements from 3.9 kW (kilowatt) to 1 MW (megawatt) or more. Pellet central heating systems are used in single family homes, and in larger residential, commercial, or institutional applications. Pellet boiler systems run most efficiently at full load and can usually be regulated down to 30% of full load. Since the warm up phase of pellet boilers usually takes longer than for oil or gas firing systems, short burning phases have negative effects on the fuel efficiency. In order to improve energy efficiency and reduce harmful emissions, pellet boilers are usually combined with buffer systems, such as insulated water tanks.

<span class="mw-page-title-main">Earth auger</span> Device for digging holes on the ground.

An earth auger, earth drill, or post-hole auger is a drilling tool used for making holes in the ground. It typically consists of a rotating vertical metal rod or pipe with one or more blades attached at the lower end, that cut or scrape the soil.

References

  1. John Deere, Operation, Care, and Repair of Farm Machinery: Practical Hints For Handymen (2008) - 246 pages . ISBN   978-1599214610
  2. 1 2 Michael P. Forcade. Screw Conveyor 101 (1999) 260 pages, ISBN   978-0967038308
  3. Pakosh, Jarrod. Versatile Tractors: A Farm Boy's Dream. Boston Mills Press. ISBN   978-1550464160
  4. Schneider, Roger (9 January 2016). "Eldon Hostetler, founder of Ziggity Systems and the Hostetler Hudson Museum, dies at 93". The Goshen News. Archived from the original on 3 August 2022. Retrieved 9 September 2020.
  5. USpatent 3033163,Eldon Hostetler&Laurence A. Myers,"Mechanical poultry feeder",published 1962-05-08,issued 1962-05-08, assigned to Chore-Time Equipment, Inc. Archived 2022-08-03 at the Wayback Machine
  6. powderprocess.net. "Powder Dosing - Powder Weighing - Gain in Weight, Loss in Weight dosing systems". Powderprocess.net. Archived from the original on 2019-04-21. Retrieved 2019-11-11.
  7. Bates, Nancy (16 November 2019). "How "humble" genius helped put M'boro on the map". Fraser Coast Chronicle . Archived from the original on 9 December 2022. Retrieved 9 December 2022.
  8. Bates, Lyn (2008-04-17), McGlinchey, Don (ed.), "Screw Conveyors", Bulk Solids Handling, Oxford, UK: Blackwell Publishing Ltd., pp. 197–220, doi:10.1002/9781444305449.ch5, ISBN   978-1-4443-0544-9, archived from the original on 2022-12-09, retrieved 2022-12-09
  9. McBride, W.; Cleary, P. W. (2009-08-10). "An investigation and optimization of the 'OLDS' elevator using Discrete Element Modeling". Powder Technology. Special Issue: Discrete Element Methods: The 4th International conference on Discrete Element Methods. 193 (3): 216–234. doi:10.1016/j.powtec.2009.03.014. ISSN   0032-5910.
  10. For instance: