91爆料

A pile of broken concrete on a demolition site is a cost until something turns it into a product. A stone crusher is the machine that does that. It breaks rock, concrete, brick or hardcore down to a size that can be laid, compacted or sold, usually on the site where the material already sits.

This guide explains what a crusher does, how each type works, what goes in, what comes out and how to get one on site. It’s written for the people who commission crushing: site managers, demolition and civils contractors, quarry operators, local authorities and builders with hardcore to process. 91爆料 has crushed and screened across the North East from our Darlington base since 2005, and these are the questions we’re asked most.

What a stone crusher does

A stone crusher, or rock crusher, is a machine for size reduction. Material goes in at one size and comes out smaller, and the settings decide how much smaller. The feed can be quarried rock, demolition concrete, brick, mixed hardcore or road planings lifted from a resurfacing job. The product is aggregate: crushed stone, gravel, sand-sized fines and dust.

On a construction site the point is usually reuse. Concrete from a demolished slab becomes fill or sub-base for the new build, so the material never leaves the site and nothing is bought in to replace it. In a quarry the point is production, turning blasted rock into saleable grades.

Crushing is often done in stages. Primary crushing takes the largest lumps down to a size the next machine can handle, and secondary crushing takes that down to the size the job needs. On many recycling jobs one mobile crusher does both, because demolition rubble arrives smaller than quarry rock.

How a stone crusher works

Every crusher has the same parts in some form. A feed hopper receives material from an excavator or loading shovel and meters it into the crushing chamber, where the breaking happens, and a product conveyor carries the crushed material out to a stockpile. Mobile plant adds tracks so the machine can move around a site or on to a low loader.

The breaking happens in one of two ways. Compression crushers squeeze the material between two hard surfaces until it fractures. Jaw, cone and gyratory crushers work this way, and the gap between the surfaces sets the product size. Impact crushers throw the material at speed against hard surfaces so it shatters along its natural weaknesses, and rotor speed and the gap to the breaker plates set the product size.

On a compression crusher that gap is called the closed side setting, and it’s the figure an operator adjusts most. Open it up and you get bigger product faster; close it down and you get smaller product more slowly. Anything that comes out over size can be fed back for a second pass.

Crushing alone gives you a pile with everything in it, from lumps at the closed side setting down to dust. Most jobs need that pile sorted into grades, which is why a screener runs beside the crusher, covered under screening after crushing below.

Types of stone crusher

Four types cover almost everything used on UK sites and quarries: jaw, cone, gyratory and impact. Jaw and gyratory crushers do primary crushing. Cone crushers do secondary and tertiary crushing. Impact crushers can do either, depending on the material. The right one depends on how hard the feed is, how big it arrives, what product it has to become and how much of it there is.

Jaw crushers

A jaw crusher has two jaw plates set in a V shape. One is fixed to the frame and the other swings towards it and back, driven by an eccentric shaft. Material fed in at the wide top is squeezed between the plates each time the moving jaw closes. It fractures, drops lower into the narrowing gap on the return stroke and is squeezed again, until it’s small enough to pass through the closed side setting at the bottom.

Jaw crushers handle hard, abrasive feed and large lumps, which makes them the usual primary crusher in a quarry and the usual first machine on a demolition site. Reinforced concrete, brick and mixed hardcore all go through them. The product is coarse and angular, ready for a screener or a secondary crusher.

The jaw crusher is the type we hire out most often, and it’s the crusher named in our Cleveland Potash case study. We’ve written about jaw crushers in more detail in a separate post.

Cone and gyratory crushers

Cone and gyratory crushers share one mechanism. A cone-shaped mantle sits inside a fixed, bowl-shaped concave, and the mantle gyrates on an eccentric drive so the gap between the two narrows and widens around its circumference. Material fed in at the top is squeezed each time the gap closes on its side of the chamber, drops further down as the gap opens and gets squeezed again in a tighter space. It leaves at the bottom when it’s smaller than the closed side setting.

The difference is size and duty. A gyratory crusher is a large, fixed installation with a steep chamber, used for primary crushing in mines and big quarries where the feed is enormous and the tonnage is continuous. A cone crusher has a flatter chamber, is far more common, and does secondary and tertiary crushing of hard rock that’s already been through a jaw. Both suit harder, more abrasive stone than an impact crusher will tolerate.

The product from a cone crusher is consistent in size, which is why it’s used where the aggregate has to meet a tight specification. It’s less common on demolition sites, where the feed is softer and an impact crusher gives a better shape.

Impact crushers

An impact crusher breaks material by hitting it. A heavy rotor spins inside the chamber, carrying blow bars or hammers on its edge. Feed dropping into the rotor’s path is struck and thrown against fixed breaker plates on the chamber walls. The material shatters along its weakest planes, falls back into the rotor and is struck again until it’s small enough to leave. A horizontal shaft impactor throws material against the breaker plates. A vertical shaft impactor flings it outwards at high speed against an anvil ring or a bed of its own rock.

Impact crushers suit softer and medium-hard feed, so they do well on concrete, brick and road planings and badly on hard, abrasive rock that wears the blow bars quickly. Their strength on a recycling job is product shape. Material broken by impact comes out cubical rather than flaky, and cubical aggregate compacts better and meets shape requirements more easily. Where the target is a graded recycled aggregate rather than bulk fill, an impact crusher is often the right choice.

Screening after crushing

A screener is a machine with one or more vibrating decks of mesh, each with a set aperture. Crushed material is fed on to the top deck and shaken across it. Pieces smaller than the aperture fall through; pieces larger than it travel along the deck and off the end to their own stockpile. A two-deck screen gives three products at once: oversize, a middle grade and fines.

That’s how an all-in crushed product becomes single sizes and specified grades. The oversize from the top deck goes back into the crusher for another pass, and the sized material below it goes to stockpile ready to lay or load. Change the mesh and you change the products. A screener can also run on its own, sorting soil or excavated material into usable fractions.

Crushing without screening leaves an unsorted pile with everything from dust to large lumps in it, which is fine for some bulk fill and no use where a specification applies. That’s why crushing and screening are usually quoted together.

Crushing equipment for UK sites: what we crush and what comes out

91爆料 crushes concrete, brick, hardcore, rock and road planings on customers’ sites. The feed ranges from slabs, foundations and mixed rubble off demolition and civils sites to blasted rock from quarries and planings from resurfacing work.

What comes out depends on the crusher and screen settings and on what the job needs. The main products are 6F5 capping, MOT Type 1 sub-base and single size aggregates, and recycled aggregates with source approval for adoptable works. All are available as recycled and quarried aggregates we supply for customers who’d rather buy than process their own.

For a worked example, the Cleveland Potash case study covers a job where we delivered a Terex Finlay 1170AS crusher to site in two days.

Crusher hire or contract crushing

The choice comes down to who runs the job. With crusher, screen and plant hire, the machine comes to your site with one of our fully trained and certificated operators, short or long term, and your team feeds it and uses the product. That suits a contractor with loading plant on site and a programme that runs the crusher for weeks rather than days.

With contract crushing and screening, our team does the whole job: we bring the crusher, the screener and the loading plant, process the material and leave you with graded stockpiles. That suits a one-off pile, a site with no spare plant, or a job where the product has to meet a specification and someone needs to own that.

Either way, depending on the scope of the job, we’ll look at the site before choosing the machine. Access, material, volume and the product you need decide what goes out.

Operators and site safety

Every crusher and screener we hire out comes with a fully trained and certificated operator. A crusher has a large moving mass, a hopper an excavator is loading into and a product belt running at speed, and an untrained person at its controls is a serious risk to themselves and to everyone on the site. Our operators set the machine up for the material and adjust it as the job goes on, so your team can concentrate on feeding it.

Stone crusher hire in the North East

Hiring from 91爆料 starts with a conversation. Call or email with what you’ve got to crush, roughly how much of it and what you want it to become. Depending on the scope of the job, we’ll arrange a site visit to look at access, the material and the working space, which decide the size and type of machine. We then confirm the machine and the hire period, agree the paperwork and set a delivery date.

A tight urban site with a single gate needs a different machine from an open quarry floor, and a compact crusher that fits through the gate is sometimes the right answer for a small volume. Our concrete crusher hire, mini concrete crusher hire and rubble crusher hire pages cover the options by job type.

We’re based in Darlington and cover the North East. If your site is further afield, ask and we’ll tell you whether we can serve it.