Coal Crushers

Introduction to Osborn Coal Crushers

The preparation of ROM coal commences the moment it is received from the mine. The Rotary Coal Breaker crushes and breaks the coal and removes the majority of the rock contamination.

The sized coal from the Rotary Breaker can then be fed into a Rolling Ring Crusher which produces a finer product.

For more specific and smaller sizing of the coal, the Double Roll Crusher is generally the preferred machine, particularly for processing the sizes required by power stations and for the export market where tight specifications are required.

Serving the South African coal market for more than 80 years, Osborn’s Coal Crushers have proven to be extremely reliable and have gained popularity as far afield as Australia, Turkey and neighbouring African countries, such as Zambia, Zimbabwe, Botswana and Mozambique.

Osborn Rotary Breakers

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ITEM DESCRIPTION

DRUM LENGTH

- A (mm)

CANOPY HEIGHT

- B (mm)

CENTRE HEIGHT

- C (mm)

TRUNNION

CENTRES - D (mm)

INLET DIAMETER - J (mm)

1 3.0 X 6.7 8330 3970 1950 860 1500

2 3.6 X 5.6 7770 4582 2090 1028 1800

3 3.6 X 6.7 9040 4582 2090 1028 1800

4 3.6 X 7.6 9910 4582 2090 1028 1800

5 4.2 X 6.7 9310 5170 2550 1017.5 2100

6 4.2 x 9.0 11400 5170 2550 1017.5 2100

Fabricated or cast screen plates are manufactured from wear resistant materials. The coal lumps are lifted and dropped onto the screen plates minimising the amount of fines passing through the square apertures. The drum is fitted with lateral beams for stiffness and square aperture screen plates with hole sizes to suit the product required.

Thrust Rollers are positioned at each end of the Rotary Breaker to prevent excessive axial float. Osborn Rotary Breakers can accept feed size of 600 mm of coal and high capacity units process up to 2000 tph. Osborn Rotary Coal Breakers have a simplistic design but are extremely durable. For this reason coal miners choose the Osborn Rotary Coal Breaker.

Replaceable steel al loy tyres are shrunk onto the machined end disc to ensure easy maintenance.

Uncrushable objects in the feed are passed through an outlet scoop into a collecting bin.

A segmented drive sprocket bolted to the machined end disc.

Special wide faced trunnion rollers support the breaker drum. Rollers are housed in self-aligning spherical roller bearings.

Chain Drive or Girth Gear and Pinion Drive

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Mineral Sizers/Roll Sizers for Primary/Secondary and Tertiary Applications

Osborn’s range of Single Shaft and Twin Shaft Roll Sizers are of a heavy duty low profile design capable of handling high tonnage throughputs using minimal installed primary power.

The Roll Sizer can be configured to operate in two ways depending on the material output size required. These being either through the centre (Centre Sizers) or down the side (Side Sizers). All Osborn Sizers are designed to operate with a single drive or a twin drive.

Osborn’s Roll Sizers are ideally suited for static, semi mobile and mobile installations. The overall weight and compact design with all the crushing forces kept within the actual body of the sizer allows for a more cost effective design without any major foundations.

Slow speed Roll Sizer concept

The Mineral Sizer’s twin rotating shaft concept was developed in the late 1970’s. It was discovered that by using relatively slow rotating shafts fitted with large teeth, large volumes of material could be passed through. The high torque and shearing force would crush the oversize material and reduce it to the required size producing minimal fines with lower noise and power consumption.

Generally the Osborn Mineral Sizer can work at a crushing ratio of 4:1 and in some cases up to 6:1 and can cope easily with handling very soft sticky material as well as dry and hard rock types. This new concept has revolutionized the underground coal mining sector, reducing blockages and transfer points.

All kinds of applications have been presented to the Sizer due to it being able to achieve up to and exceeding 10,000 tonnes per hour with material feed size over 2m3. The Osborn Mineral Sizer has been designed to be installed in primary, secondary and tertiary applications with a final outfeed size of nominal 50mm.

Centre Sizing Shafts rotate inwards

Side Sizing Shafts rotate outwards

Mineral Sizer

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The working area length can vary between 1- 4 meters depending on capacity required (working throat). This is in 500 mm sections.

Model Number Type of Sizer

550 Centre and Side Sizer

650 Centre and Side Sizer

800 Centre and Side Sizer

1000 Centre Sizer

1250 Centre Sizer

1450 Centre Sizer

1650 Centre Sizer

Mineral Sizers – Range of Models

Osborn’s range of Mineral Sizers start at our 550 model through to a 1650 model. Model sizes are determined by the centre distance in mm between the main rotors.

Tooth and Rotor Design

The basic concept of the Osborn Mineral Sizer is of counter rotating rolls turning towards each other in the centre Sizer design and away from each other in the side Sizer design. The Primary Sizers can be configured with 3 tooth and 4 tooth segments.Secondary and Tertiary Mineral Sizers would be constructed with multi tooth segments that are bolted to the tooth carriers mounted on the main rotors.

The success of the crushing action is very dependent upon the tooth configuration with the size and shape of the teeth specifically selected for each Mineral Sizer application. The teeth are designed to be locked into machined recesses on the shaft that ensures easy replacement of the teeth caps without the need to remove the entire rotor assembly.

Heavy duty clamps hold the teeth in place on the rotor and each row of teeth is torqued through tensioning bolts which are located outside of the feed stream.

Mineral Sizer

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Construction features of Osborn Mineral Sizers

Main frame • Fabricated from carbon

steel.• End plates are machined

from solid plate and horizontally split along the rotor shaft centre line.

• Side frames are fully welded, of ribbed construction and machined to size, spigotted and bolted to form a highly robust assembly capable of containing any dynamic forces created whilst the machines is in operation.

Shaft Assemblies

• Rotor shafts and drive gears are machined from high carbon steel.

• Shaft bearings are of the spherical roller type.

• Bearings and cartridges are retained on each end of the shaft by large locking nuts so that all the thrust on the teeth and shafts is contained inside the shaft and not transferred onto the bearings.

Wear plates • Osborn mineral sizers

are fitted with wear plates completely covering the inside of the body and sizing chamber.

• The wear plates are made from high wear steel and are bolted to the sizer to allow ease of replacement.

Lubrication • All gears in the Osborn sizer are lubricated through an oil bath. • The reservoir is fitted with an oil level sight glass, magnetic drain plug and oil sampling point.

Sizing Teeth Osborn provides a range of sizing teeth suitable for different applications. Type and fitment thereof varies accordingly.

Modular Reduction Gear Box and DrivePinions and gears are machined, carburised and ground from high tensile steel. All bearings are spherical roller type. Gearbox selection is sized to include a high safety factor.

Drive Details• A TEFC electric motor drives through a fluid coupling which is fitted with an inspection cover for maintenance of the coupling. A reduction gearbox is bolted to the transfer box which is also fitted with inspection covers. The final drive is via a spur gear which

is housed in the transfer box.• All rotor drive gears (in & output) in the transfer box are spline coupled onto their mating shafts for ease of maintenance,

replacement if necessary and timing adjustments. The reason for timing adjustment, is for rotor self-cleaning purposes. • Also different rotorshaft ratios can be obtained by fitting different spur gears other than the 1:1 ratio.

Features of an Osborn Mineral Sizer

• Low shaft rotor speed• Low wear on working parts• Low noise levels• Low generation of fines• Minimum dust created• Crushing forces kept within the sizer housing• Modular construction of machine• Teeth wear parts can be easily replaced in situ• Low feed height

Mineral Sizer Construction

• Electric Motor/s Prime mover• Fluid Coupling• Heavy Duty Design Gearbox (continuously rated)• Main Shaft Support Frame• Main Shaft and Support Bearings• Toothed Segments• Wear Plates / Cleaning Combs

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Breaker Bar Assembly

SIDE ELEVATION

PLAN VIEW

END ELEVATION

Sup

port

ed A

rea

Wor

king

Are

a

Drive End Link Box

Working Area

Side Frame

Prime MoversGearboxes

Main Rotors with Toothed Segments

Fluid Coupling Housing

Non-Drive EndNon-Drive End BRG Housing

Speed Sensors

Non-Drive End Wear Plate

Cleaning Combs

Drive End Wear Plate

Inspection Covers

Shaft Centres

Breaker bar support

Primary 3 Tooth Sizers

The Osborn Mineral Sizer has counter rotating rolls, driven by the electric motor prime mover through a fluid coupling and connected to a heavy duty gearbox.

The final drive to the rotors is from the reduction gearbox through to spur drives which are located in the mainframe link box.

The gears are shrink mounted onto their mating shafts and when assembled into the gearbox housing, provide a gear train to give the required ratio. Input and output shafts are splined to give simple assembly and better drive, thus reducing damage through the continuous shock loading the Mineral Sizer is subjected to.

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Rolling Ring Crushers

This Rolling Ring Crusher “hammermill” design has the capability to reduce a coal feed size of 500 mm to 25 mm in one pass. Capacities are in excess of 2 000 tph dependent upon rotor speed, percentage lump in feed, hardness, structure and moisture. The crushers are fitted with cleanout doors to remove tramp iron and uncrushable materials from the metal trap at the rear of the machine.

Construction Features

1. ROTORMachined from heat-treated steel to minimize deflection. Designed

with an excessive safety factor for critical speed requirements.

2. FRAMEThe housing is fabricated from top quality steel plate and stress

relieved prior to machining.

3. BREAKER PLATEPre-screens undersize material through breaker grate to minimize fines production, alleviate dusting and decrease wear on crusher.

4. ADJUSTABLE DROP CAGEThe machine is furnished with a drop cage. This feature produces

absolute size control within the product range of the machine. It

also permits quick cleanout in the event of a power failure and

blockage.

Adjustment of the American Rolling Ring Crusher can be performed

in 3 different ways:

(1) The hand wheel

(2) The hand wheel with Reduction Gearbox

(3) The motorised gearbox

BEARINGS (NOT SHOWN)Heavy-duty anti-friction bearings, which are enclosed in dust and oil

tight pillow blocks. The pillow blocks are mounted and dowelled on

machined surface. Split bearings are optional.

5. LINERSThe liners consist of high impact and wear-resistant plates. The

liners can be easily replaced without dismantling the machine.

6. SHREDDER RINGSEach ring has multiple cutting edges and is reversible. The rings

revolve at slow speeds and split the coal, instead of crushing

it, producing a granular product with minimum fines. If rings

encounter tramp metal, they are free to deflect on their shafts.

The Shredder Rings can be changed either through the rear

inspection panels or from the top of the machine. This may also be

used to lift out the whole shaft assembly.

3

2

6 1

5

4

Hand wheel (and gearbox on large machines) for drop cage adjustment.

A

E

C

D

B

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Access door for shredder ring change and metal trap clean out.

Breaker plate, screen plates and rotor assembly.

Breaker plate adjustment screwson both sides.

Heavy duty bearing and plummer blocks for rotor shaft.

Pivoted arrangement for ease of access is an optional extra on all machines.

Access for inspection of drop cage and screen plates.

MODEL A B C D EWS 16 BG 667 508 1346 1525 965WS 28 BG 667 787 1346 1805 965WS 46 BG 667 1219 1346 2237 965WS 70 BG 667 1829 1346 2846 965AC 3B BG 667 1232 1632 2470 1168AC 3D BG 667 1537 1632 2775 1168AC 3F BG 667 1842 1632 3080 1168AC 7C BG 864 1842 2038 3131 1473AC 7D BG 864 1994 2038 3283 1473AC 7F BG 864 2299 2038 3588 1473AC 7J BG 864 2756 2038 4045 1473AC 57G BG 1219 2959 2571 4394 2032AC 72H BG 1372 2819 2931 4458 2337AC 72J BG 1372 3105 2931 4743 2337

NOTEDimensions shown are approximate only and should not be used for plant layout.

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Double Roll Crusher

Osborn Double Roll Crushers can be used for primary and secondary crushing. The Double Roll Crusher is generally regarded as a 4:1 feed to

product ratio crusher, however in some instances, dependent upon material friability and hardness, it is possible to achieve a 6:1 crushing ratio.

The feed material should enter the centre of the gap between the two rolls and spread across the full roll width for maximum efficiency and this

ensures a uniform product size distribution.

For strict coal product specifications the Osborn Double Roll Crusher is preferred. It is important to understand the material characteristics, as

the type of coal will often vary considerably. Hardness, rock content, friability and moisture content are the major factors that need to be identified,

together with the crusher capacity, maximum lump size, required product size and the amount of fines that are acceptable.

Efficient crushing will lower the power requirements and increase the life of the crusher segments. When the correct crushing ratio is used and

the optimum roll diameters selected, the segments will grip the feed material more efficiently and it will also not allow pieces to roll on top of the

segments due to the incorrect nip angle, this assists in reducing wear.

Crushing rolls and drive

Each roll assembly comprises of renewable and reversible toothed segments, bolted and keyed to a robust hexagonal hub with the nuts inside the

hub. Locking nuts are securely located in fabricated pockets in the drum. This enables removal and replacement of segments from the outside

using only one tool (Allan Key). Bolt heads are protected from excessive wear by being counter sunk in recesses on each segment. Teeth are

arranged in a staggered formation on the segments to prevent tooth on tooth impact. Tooth proportions are designed for the particular product

requirements.

The rolls are separately driven by two identical motors, through sets of vee belts which are connected between the gearbox pulley and the flywheels.

The drive arrangement is free standing with the electric motors mounted on adjustable base plates.

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Frame and Canopy

Crusher ModelDia x Width mm

A B C D

24 x 48 608 1030 2820 920

30 x 36 608 1251 3125 1180

30 x 54 608 1251 3125 1180

30 x 72 608 1251 3125 1180

36 x 36 808 1880 3412 1430

36 x 54 808 1880 3412 1430

36 x 72 808 1880 3412 1430

Dimensions subject to change. Please consult Osborn for confirmation of dimensions.

Release Mechanism

Uncrushable material entering the rolls will load the springs causing them to compress and allow the passing of the non crushable objects.

Compression springs are fitted at one end and act on the bearing housings of one roll. Spring adjustment bolts and shim plates are fitted for

adjusting the roll position. Hydraulic roll adjustment and force relief cylinders can be supplied instead of the springs as an optional extra.

Fabricated channel beams serve as the main frame support. For ease of adjustment, machined low friction polymer pads are provided. Inspection

doors are provided at the roll ends on the non-drive side as well as on the crusher ends. Flanges are provided on the top for connecting a feed

chute.

Head Office:57 Jansen Road, Elandsfontein

PO Box 8182Elandsfontein, 1406

JohannesburgSouth Africa

Tel: +27 11 820 7600 Fax: +27 11 388 1136

E-mail: osborn@osborn.co.za www.osborn.co.za

Companies of the Astec Aggregate and Mining Group

www.osborn.co.za www.telsmith.com www.rockbreaker.com www.astrcmobilescreens.com www.kpijci.com

All rights reserved. Unless otherwise indicated, all materials on these pages are copyrighted by OSBORN. No part of these pages, either text or image may be used for any purpose other than personal use. Therefore, reproduction, modification, storage in a retrieval system or retransmission, in any form or by any means, electronic,

mechanical or otherwise, for reasons other than personal use, is strictly prohibited without prior written permission.

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