Key Facts
- Total mass:
- Up to 90 t
- Motor power
- Up to 185 kW
- Maximum feed capacity
- Up to 2,200 t/h
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TAKRAF Bradford Breakers
The Bradford Breaker simultaneously sizes and cleans raw coal. It is commonly used for:
- Primary run-of-mine (ROM) coal crushing and cleaning
- Secondary coal crushing and cleaning
The Bradford Breaker can also be used to separate other materials.
Machine sizes are available for feed rates from 100 to 2,200 t/h and more.
Bradford Breakers are sold under license.
The Bradford Breaker is essentially a large rotating cylinder powered by an electric motor through a reducer and chain drive. Coal is lifted and dropped in the cylinder, shattering on impact. Product-sized coal passes through perforations in the cylinder shell, while reject material such as stone and debris is discarded separately.
Semi-mobile Bradford Breaker
A semi-mobile Bradford Breaker offers the junior and small mining sector the benefits of the Bradford Breaker in a more compact machine, which is mounted on a relocatable support structure. This allows for:
- Ease of transport to move the Bradford Breaker as mining progresses to another block or resource
- Ability to position the Bradford Breaker as close as possible to mining operations, therefore reducing conveying costs
- Simple civil works, as a civil template is provided to ensure correct positioning of the hold-down bolts in the cast concrete
Key components
The ends are of fabricated steel. The feed and discard ends have conical openings to facilitate the entrance of the feed and to reject tramp iron, rock and other debris. Each end has seal paths to run against seals fitted to the dust hood and the feed and discard chutes.
The universal section beams are fastened to the trunnion ends with high tensile, minimum clearance HEX head bolts. The beams are jig drilled for accuracy and ease of assembling screen plates.
Outer flanges are lined for three screen plate lengths from the feed end.
Screen plates are made from VRN 400 material or equivalent, having square holes for the desired product size to pass through.
The plates are fastened to the beams with high tensile bolts and special washers. Adjacent plates do not overlap.
The first row of plates at the feed end comprises blank plates to minimize the possibility of fines build up on the end plate of the dust hood, which may occur depending on the particle size distribution (PSD) of the feed.
The lifting shelves are fabricated from VRN 400 steel plate. They lift the material and aid in material flow through the breaker for efficient scavenging of tramp/uncrushable materials.
Their positions in the drum can be arranged to increase or reduce the rate of axial flow of material through the drum.
The feed deflectors are made from VRN steel plate and aid in material flow through the breaker. Their function is to rapidly move material away from contact with the feed end trunnion into the lifter section. The angle of the deflectors is not adjustable.
The two refuse ploughs are fabricated from VRN 400 steel plate and designed to direct refuse through the discard end opening of the breaker. Two or three ploughs are fitted to ensure accurate balance rotation and maximum removal of rock and debris.
The tyres are hardened steel forgings, completely machined and shrink fitted onto the trunnion ends.
The four support wheels are heavy section, alloy steel forgings with hardened, shrink-on rims. The hubs are shrink fitted onto alloy steel shafts.
Feed and discard tyres run against beveled thrust wheels if the drum “floats” out of its neutral position.
These are heavy duty, self-aligning spherical roller bearings with tapered bores and adapter mountings. The housings are split for ease of inspection and maintenance.
Wheel stands are fabricated from mild steel with machined bearing pads and are provided with adjusting screws for accurate mounting and aligning of wheel assemblies.
The slack side of the chain passes over a spring-loaded adjustable jockey sprocket to provide the correct chain tension during operation.
The dust hood of fabricated mild steel plate is fitted with liners of VRN 400 or equivalent on the lower section. The top half is removable as a unit to facilitate maintenance access. The bottom half has doors along the side for inspection and maintenance access. The hood ends have dust seals set to contact machined seal paths around the peripheries of both trunnion ends.
The breaker is shipped in sub-assemblies for final assembly on site. The drum assembly is transported to site fully assembled in order to reduce installation time.
Benefits
Durable design
Grid type screen plates on the Bradford Breaker ensure high cylinder strength and a long life. The machine is driven from one end only by a simple drive assembly comprising a squirrel cage motor, fluid coupling, gearbox, and final chain drive.
Handles large ROM lumps with ease
Large feed and discard openings allow the passage of sizable ROM lumps of coal and tramp material without the risk of blockage. Internal lifters can be arranged to accelerate or retard material flow rate through the machine.
Effective dust control
Fines generation is minimized since the coal fractures along natural cleavage lines, with the machine designed to contain dust, permitting effective suppression or extraction and treatment of dust-laden air.
Low operating costs
The Bradford Breaker operates with minimal downtime and offers low power consumption compared to other machines with similar crushing duties, keeping operating costs relatively low.
