A compactor is a machine or mechanism used to reduce the volume of waste material or soil through compaction by the action of packing it down to reduce the volume, or to pack loose material down so it has less voids and is solid i.e. stone for road base.
In many parts of the world, road rollers are still known colloquially as steam rollers, regardless of their method of propulsion. This typically only applies to the largest examples (used for road-making).
Since the effectiveness of a roller depends to a large extent on its weight, self-powered vehicles replaced horse-drawn rollers from the mid 1800s. The first such vehicles were steam rollers. Double-cylinder designs were preferred. Single-cylinder steam rollers were uncommon and unpopular, as the power impulses from the steam engine would produce slight waves in the road. Some road companies in the United states used steamrollers through the 1950s, and in the UK, some remained in commercial service until the early 1970s.
As internal combustion engine technology improved during the 20th century, kerosene-, gasoline- (petrol), and diesel-powered rollers gradually replaced their steam-powered counterparts. The first internal-combustion powered road rollers were very similar to the steam rollers they replaced. They used similar mechanisms to transmit power from the engine to the wheels, typically large, exposed spur gears. Some companies did not like them in their infancy, as the engines of the era were typically hard to start, particularly the kerosene-powered ones.
Virtually all road rollers in commercial use now use diesel power.
Types of Compactor Edit
Normally powered by an engine and with hydraulic drives, compactors take many shapes and sizes.
- Waste or landfill site Compactors; These have a large bulldozer blade is mounted on a loader chassis fitted with spiked wheels which is used to drive over waste deposited by waste collection vehicles (WCV's)or from waste transfer containers, in the UK.
In construction, there are three main types of compactor;
- plate compactor, or "jumping jack" The plate compactor has a large vibrating baseplate and is suited for creating a level grade, while the jumping jack compactor has a smaller foot. The jumping jack type is mainly used to compact the backfill in narrow trenches for water or gas supply pipes etc
- Road Roller. The roller type compactors are used for compacting crushed rock as the base layer underneath concrete or stone foundations or slabs. .
- Vibrating RollerRoad rollers may also be vibrating rollers. They come in various sizes from pedestrian controlled,up to large self propelled rollers weighing up to 20 Tons.
Road rollers work by using the weight of the vehicle to compress the surface being rolled. Initial compaction of the substrate is done using a pneumatic-tyred roller, where instead of the single- or double-drum is replaced by two rows (front and back) of pneumatically filled tyres. The flexibility of the tyres, with a certain amount of vertical movement of the wheels, enables the roller to operate effectively on uneven ground. The finish is done using metal-drum rollers to ensure a smooth, even result.
Rollers are also used in landfill compaction. Such compactors typically have knobbed ('sheeps-foot') wheels and do not attempt to achieve a smooth surface. The knobs aid in compression due to a smaller surface area being in contact with the ground.
The roller can be a simple drum with a handle that can be operated by one man, and weighs 100 pounds, all the way up to a massive ride-on road roller weighing 21 short tons (44,000 lb or 20 tonnes) and costing more than US$150,000. A landfill unit can weigh 59 short tons (54 tonnes). On some machines the drums may be filled with water.
- Manual walk-behind
- Powered walk-behind (electric or diesel/gas powered)
- Trench roller (manual units or radio-frequency remote control)
- Ride-on with knock-down bar
- Ride-on articulating-swivel
- Tractor mounted and powered (this may be a 'one-off' – see gallery picture below)
Drums come in various widths: 24-to-84 inches
- Single-drum sheeps/pad-foot (soil)
- Single-drum smooth (asphalt)
- Double-drum (duplex) sheeps/pad-foot (soil)
- Double-drum (duplex) smooth (asphalt)
- 3-wheel cleat with bulldozing blade (landfills)
Variations and featuresEdit
- On some machines, the drums may be filled with water on site to achieve the desired vehicle weight. When not filled, the lighter machine is easier and cheaper to transport between worksites.
- Additional compaction may be achieved by vibrating the roller drums
- Water lubrication may be provided to the drum surface to avoid hot asphalt (for example) sticking to the drum
- Hydraulic transmission permits greater design flexibility (early examples were direct mechanical drive) and reduces the number of moving parts exposed to contaminants of construction sites
- Human-propelled rollers may only have a single roller drum
- Self-propelled rollers may have two drums, mounted one in front of the other (format known as 'duplex'), or three rolls, or just one, with the back rollers replaced with treaded pneumatic tyres for increased traction
Other types of Compactors Edit
Scrap Compactor Edit
Different compactors are used in scrap metal processing, the most familiar being the car crusher. Such devices can either be of the "pancake" type, where a scrap automobile is flattened by a huge descending hydraulically-powered plate. The other type is the baling press, where the automobile is compressed from several directions until it resembles a large cube.
Waste Compactor Edit
Many retail and service businesses, such as fast food, restaurants, and hotels, use compactors to reduce the volume of non-recyclable waste as well as curb nuisance such as rodents and smell. In the hospitality industry tolerance for such nuisances is particularly low. These compactors typically come in electric and hydraulic operation, with quite a few loading configurations. Most popular loading configurations fall under the following:
- Secured Indoor Chute.
These compactors are almost exclusively of welded steel construction for two reasons: durability under pressure and exposure to the elements, as compactors are installed either completely outdoors or sometimes under a covered loading dock.
Trash Compactor Edit
There are also trash compactors designed for residential use which, likewise, reduce the volume, smell, and rodent problems of Waste. This can be especially valuable for households which regularly dispose of items such as disposable-diaper boxes or the non-edible portions of vegetables from a large garden. Related to this, there are frequently limits to the number of trash bags/receptacles that can be left outside for residential pickup, which further renders such compactors beneficial to such households.
Compactor & Roller Manufactures Edit
- Aveling-Barford Steam and Diesel rollers
- Case CE
- Caterpillar 815, 815B, 815F, 825, 825B, 825C, 825G, 835, CS 563E, CS 583E
816, 816B, 816F, 826B, 826C, 826G, 836
- Dyna-pac(= Atlas Copco)
- Ingersoll Rand (Volvo Construction Equipment)
- Massey Ferguson Construction (Compactors) model C44c, C55c, C66c
- Marshall and Aveling Marshall steam and Diesel models
- Stothert & Pitt Diesel rollers 10cwt to 10 ton.
- Terex CMI-division
- Vibromax now JCB
- List of Construction Plant Manufacturers
- Landfill compaction vehicle
- Road Roller Association
- Roller (agricultural tool) - for farm rollers
- Roller (disambiguation) - for other types of roller
- Steam roller - the first powered road rollers
- Massey Ferguson Industrial & Construction Equipment by J.Farnworth
- Caterpillar Century by E.C.Orelmann
- Road Roller Association – UK-based society dedicated to the preservation of steam (and motor) rollers and ancillary road-making equipment.
- Preventing Injuries When Working With Ride-On Roller/Compactors, a publication from the U.S. National Institute for Occupational Safety and Health
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