Feature: Crushing & screening equipment

By Steve Skinner11 November 2010

A Sandvik UJ640 jaw crusher is being used to break up to 800 tonnes/hour of blasted rock into sizes

A Sandvik UJ640 jaw crusher is being used to break up to 800 tonnes/hour of blasted rock into sizes below 150 mm at Heidelberg Cement’s Kållered quarry near Gothenburg, Sweden.

Quarry operators are looking for greater productivity, improved product consistency, adaptability, reliability and of course lower running costs from their crushing and screening equipment. They also want this in a smaller, lighter and more transportable package. So how are manufacturers responding?

Through redesigned components and an increase in power to 932 kW, the capacity of Metso's new Nordberg MP1250 cone crusher for static plants has been increased by +30% over its MP100 predecessor to more than 1000 tonnes/hour, depending on the application and material.

With installation that requires the same physical footprint as the company's earlier model, the new cone offers increased productivity from a compact crushing unit that also offers more efficient use of energy.

A redesigned mainframe improves durability, while a higher fulcrum point, which increases the parallel crushing action between the bowl and the mantle, and an increased throw (the difference between the closed side setting and the open side setting) lead to more work per cycle. An automatic system continually monitors product size and adjusts the crusher settings for consistency.

Metso has also upgraded its Superior 60-110E primary gyratory crusher so that it's -20% lighter, yet capacity is the same as found in the earlier 60-100 MK-II crusher. A spokesperson said, "Through the redesign and an increase from 514 rpm to 600 rpm mean we've been able to enhance performance while increasing reliability."

Recycling

At Bauma, BHS Sonthofen unveiled its Procrush semi-mobile unit equipped with either a rotor centrifugal crusher or a rotor impact mill. Capable of handling a feed size up to 56 mm the Procrush can process up to 90 tonnes/hour and the company says it produces high quality fractions with excellent particle shape.

Fitted with a feeding hopper and belt conveyors for both input and output the unit sits on hydraulic legs that enable it to lift itself for loading without the need for additional equipment. "This unit offers a flexible solution for changing locations and applications," marketing manager Birgit Gicklhorn told CE.

Also at Bauma, following two years of development, Sandvik unveiled its QI240 mobile impact crusher. Designed to process demolition materials on site, the QI240 has been developed to offer contractors mobility, productivity, ease of transport, and simple operation, while also reducing environmental impact.

Spokesperson Melissa Baker said, "The compact design alongside high levels of production and superb product shape also make this an ideal unit for use in smaller quarries where space and machine manoeuvrability are at a premium."

Equipped with a pre-screen to remove undersize material - thereby maximising throughput and reducing wear - the unit is also fitted with an underpan feeder to reduce the spillage traditionally associated with impact crushers.

The underpan feeder also protects the conveyor belt as all of the material travelling at high speed from the rotor is collected on the wear-resistant underpan feeder liners, before being delivered onto the conveyor.

Two hydraulically adjustable apron curtains can be positioned to convert the machine from working as a primary to secondary impactor for the production of smaller end product.

Optimum flow

Alongside the QI240, Sandvik also used Bauma to launch its six-strong CV200 series of vertical shaft impactors (VSI) designed for the mining, construction and recycling sectors. The entry level CV215 has a capacity of 10 tonnes/hour while the range-topping CV229 can process up to 600 tonnes/hour.

"In developing the CV200 series our engineers focussed on providing economy, capacity, reliability and reductions in maintenance as well as cutting power requirements and therefore emissions. We also looked at health and safety aspects to reduce risks," said Rowan Dallimore, product line manager for Sandvik impact crushers.

The rock-against-rock crushing technique employed by the VSI offers various benefits including constant product gradation even as the wear parts of the rotor erode. "Contamination rates too are extremely low as no wear parts are used to directly crush the rock," said Mr Dallimore.

Specific advantages of the CV200 series include reduced operational costs per tonne, quick and easy replacement of wear and spare parts, consistent, easily controlled product grading and reduced power consumption.

New rotor and wear parts lead to increased rotor life and reduced maintenance as well as an increased capacity without impacting on fuel consumption.

The new VSIs also feature Sandvik's Bi-Flow system, which in conjunction with the high performance rotors and new wear parts results in a reduction in power demands. Mr Dallimore said that up to 20% of throughput can be handled through the Bi-Flow system, which offers huge savings in electricity consumption.

The Bi-Flow system directs a second flow of material via rock-lined chutes against the stone bed in the crushing chamber and in the opposite direction to the rotor-fed material. The opposing flows result in greater impact, cleavage and attrition.

A fully enclosed hydraulic cabinet enables quick and easy adjustment of the rotor throttle and drive-belt tensioning as well as housing a semi-automatic greasing system and maintenance tool kit. An integrated feed tube replacement system has been designed so that a single operator can replace the feed tube via an access point reachable from the crusher inspection door.

Mr Dallimore said, "This greatly reduces cost and space claim while reducing the health and safety risks associated with what was traditionally a time consuming, costly and heavy duty operation."

Kleemann's 350 tonnes/hour capacity MR 110 Evo and 450 tonnes/hour MR 130 Evo use a new material flow concept to ensure there is no restriction to the flow of material through the crushing process. The discharge chute beneath the crusher is 100 mm wider than the inner width of the crusher and the discharge belt is a further 100 mm wider than the chute.

"Material is quickly transported away from the critical area under the crusher and the increased flow rate reduces wear," said marketing manager Mark Hezinger.

Even before the crushing chamber, Kleemann studied material flow and optimised the widths of the feeder troughs and grizzly to aid smooth transport of material to the crusher opening.

"The behaviour of the independently vibrating double-deck grizzly and chute has been improved, and together with the new crusher bypass, which features changes to both its form and geometry, the entire system has been relieved of load. This has lead to increased performance and reduced wear," said Mr Hezinger.

A new inlet geometry allows for better penetration of material into the range of the rotor, while the wear characteristics of the new C-form rotor ledges has been improved so the edges remain sharper for longer.

Mr Hezinger said, "This gives a higher quality end product, which is further enhanced by the new fully hydraulic adjustment of the crushing gap. Not only can the gap be adjusted via the crusher's electronic control unit, but the calculation of the zero-point is possible while the rotor is running, which has eliminated the need for impact toggles."

The zero-point is the last position at which the rotor can turn freely before the impact plates and blow bars touch.

Growing families

Following the success of its PC1 and PC2 models, Hartl Powercrusher has extended its range with four new units. The PC3 features an impact crusher with an inlet opening of 1,2 m, while the PC4 is a jaw crusher with an inlet of the same dimensions. Both mid-range units have been designed for recycling applications as well as for processing natural stone and both can process up to 300 tonnes/hour.

"The size and weights of the PC3 and PC4 are suited to transportation. Both are extremely flexible and can be moved quickly between job sites, where they can be set up and ready to crush in less than 30 minutes," said marketing manager Nathalie Palmetshofer.

The new range-topping PC5 impact crusher and PC6 jaw crusher feature inlet openings of 1,3 m and can process up to 400 tonnes/hour. Both units are equipped as standard with a double-deck independent heavy duty grizzly and the lower deck is changeable, offering flexibility in the material size deposited to the side conveyor.

The main conveyor belts on the PC5 and PC6 can be lowered hydraulically to ease access to the area under the crusher outlet as well as to simplify replacement of the conveyor belt.

Ms Palmetshofer said, "The complete range has been designed to accept Stage IIIB compliant engines, while the use of wider tracks affords increased stability and mobility even in difficult ground conditions."

Fellow Austrian manufacturer, Rubble Master launched its RM80 Go! at Bauma, following the introduction of the concept with the RM70 Go! at Intermat last year.

The 'Go!' concept is based on providing a crusher that is quick to set up and easy to operate via a simple to use operator interface so that someone with little specialist knowledge can still produce high quality output.

Kormann Rockster Recycler's 32,6 tonne Turbo-Crusher R1100 track-mounted impact crusher is the company's largest mobile crusher and was designed in response to customer demand for a bigger machine.

Kormann Rockster CEO Wolfgang Kormann said, "Our existing series, including the top of the range 25 tonne R900, has already proved itself, however we received a large volume of requests for a bigger machine covering a wider market segment. The Turbo-Crusher R1100, with a throughput of almost 350 tonnes/hour is our answer."

Equipped with a hydraulic drive, the Turbo-Crusher R1100 features a two-step, 1,8 m long pre-screen, which increases throughput and reduces wear. The main conveyor can be lowered hydraulically, which eases access to clear blockages as well as simplifies the fitting of the optional RS94 screen box.

Powerscreen Pegson, part of Terex, has extended its range of crushers with the launch of its XH320SR impact crusher.

Capable of processing up to 320 tonnes/hour, the XH320SR has been designed for recycling, demolition and quarry applications. An efficient direct drive powers the crusher, while a double-deck grizzly feeder with an underscreen and load management system combine to increase throughput and reduce wear costs. The unit also features an under pan feeder, new impact chamber with four bar rotor, a twin apron design and hydraulic overload protection.

MFL's new RCI100.100T Stoneformer impact crusher has been designed for processing natural stone, demolition debris, asphalt and coarse gravel at a rate of up to 170 tonnes/hour. Options include an extra finger screen for pre-screening and a rigid, laterally inserted conveyor for fine material. The 4 m3 hopper has hydraulically foldable walls, while a 1 m x 2,8 m vibrating chute with a two level grid conveys material quickly to the crusher inlet.

The 35 tonne tracked unit is powered by a 200 kW Caterpillar diesel engine in combination with an electric motor producing 132 kW. Marketing manager Michael Fasching said, "Improvements throughout the unit have resulted in a +15% increase in efficiency compared to our previous generation crushers."

A modified programmable logic controller (SPS) not only manages 'just in time' throughput and highlights faults, but also enables remote maintenance via a modem connection. "The SPS also offers users the benefits of wireless remote control for both drive and the vibrating chute. Additionally, four further variable functions can be controlled remotely," said Mr Fasching.

Terex Finlay has also extended its family of crushers and screens with three new crushers and the 694+ tracked screen with an inclined 4-way split screen and triple deck box with 27,9 m3 of screening area.

The company's J-1480 tracked crushing unit featuring a Terex Jaques single toggle jaw crusher is capable of processing up to 600 tonnes/hour. The unit is available with direct drive for improved fuel efficiency and a greater use of power or hydrostatic drive, which offers reversible operation for clearing blockages and for demolition applications.

Featuring a vibrating pan feeder linked to an aggressive independently driven pre-screen for optimum separation, the J-1480's 10 m3 hopper capacity can be increased though optional side extensions.

The Terex Finlay C-1550 tracked cone crusher incorporates a Terex 1300 cone crusher with direct drive. The machine features a pre-screen system with a single deck screen and 1,2 m belt to remove fines, thus improving the capacity of the cone and reducing wear.

The variable speed cone has a tramp relief system to clear blockages of non-crushable material such as steel and 'on the fly' closed side setting, while the 8 m3 hopper is equipped with an automatic metal detection and purge system to protect the cone.

Also new from Terex Finlay is the I-130RS tracked impact crusher with detachable sizing screen. Incorporating a Terex Cedarrapids three or four bar rotor 1313 impact chamber with hydrostatic drive, the unit features hydraulically assisted apron settings and a recirculating system for over-size material.

The 'quick detach' 3,6 m x 1,5 m double deck screen can be easily removed, while the 9 m3 capacity hopper features a variable speed pan feeder and independent pre-screen for optimum separation even when the feeder speed is reduced.

Screening

In the same vein as crushing units, next generation screens are also being developed to increase productivity from a reduced footprint.

Sandvik's tracked QE440 has +40% more screening area than the QE340 it replaces, while the stockpiling conveyors are both wider and higher to deal with the increased production and to enable larger stockpiling. The 5,5 m x 1,75 m scalping area lends itself to high levels of production, yet the unit's overall dimensions mean it is still easily transportable between sites.

Built on a heavy duty crusher-type chassis, the top deck of the QE440 can be equipped with punched plate, heavy duty mesh, rock fingers or grizzly bars, while the bottom deck features either heavy duty mesh or fingers to match the application and material requirements.

At the beginning of this year Metso unveiled two new tracked mobile screens in the shape of the three deck ST4.8 and two deck ST3.8. The first screens to be manufactured at the company's Lokotrack factory in Tampere, Finland, the new models feature new anti-spillage systems and improved cooling to deal with high ambient temperatures.

Product manager for mobile screens, Adrian Wood told CE, "The market demand for increased capacity and higher quality end products has already seen a major increase in screen size. I believe this trend will continue to the point where mobile equipment will have a similar capacity to most fixed plant installations."

Mr Wood said the development of the screen itself is critical to higher capacity and he believes technology regards increased throw and dual and triple screens will lead the way as the need to maximise the whole screen area will become more important.

"The focus for manufacturers is to find methods to achieve greater accuracy using smaller areas to achieve higher capacities, while fitting in to similar size physical envelopes as found with today's machines," he said.

Powerscreen's new range topping Warrior 2400 is a heavy duty tracked screen designed to handle large feed sizes while remaining transportable. "The Warrior 2400 has been designed to meet the needs of end users at the larger end of the quarrying, mining and recycling sectors," said Pat Brian, global sales director.

Featuring a heavy duty inclined screen with a high amplitude triple shaft drive, the Warrior 2400 is suited to screening, scalping two or three way splitting and stock piling. Hydraulic folding tail and side conveyors aid set-up while a simple-to-use electronic control system enables operators to monitor and diagnose any issues on site via an LCD. Mr Brian said, "In due course we will also offer the option of dual power."

Optimisation

Be it in static plants or across mobile units the challenge is to increase productivity while retaining minimal overall dimensions. Particularly with mobile units, manoeuvrability and transportability remain as important as productivity. While the opposing demands will eventually lead to compromise, the newest generation of equipment demonstrates that for the time being at least, manufacturers can offer more for less.

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