Sandvik Construction A world leader in Construction Module 2b How machinery factors affecting crusher performance Sandvik Construction

Safety first Safety is our top priority Protective Equipment Emergency Number Emergency Exit Assembly Point Alarm 2 Sandvik Construction Sandvik Construction

Crushing concepts Machinery factors What are we about to examine The major machinery influences on crusher performance, which are setting throw chamber volume speed Sandvik Construction

Crushing concepts Machinery factors Control features Jaws Cone HSI VSI Chamber Limited by plate profile Various & many Limited by position of curtains and setting on bottom curtain. Different depth rotors Throw Limited X Speed Yes Setting Other Nip Angle Automation Bi-Flow operation Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Control features Nip Angle Width Gape Flywheel speed What features can be changed? Sandvik Construction Features of the Jaw Crusher this relates to all Jaw Crushers Nip Angle this is important with regards to the flow of material when crushing because if the nip angle is wrong then material will bounce back up rather than be crushed Gape and Width are impotant with regards to the top size of material that we can accept

Crushing concepts Machinery factors Jaw crushers Control features What machine factors can be used to adjust the performance of a jaw crusher? Closed side setting (C.S.S.) Jaw plate tooth profiles Speed Stroke Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Manual setting adjustment Manual shim-type setting regulation Hydraulically assisted shim-type setting regulation Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Hydraulic wedge setting adjustment Hydraulic Setting Wedge System = = The setting is adjusted with the help of wedges. Adjustment is carried out “automatically” simply at the push of a button. Sandvik Construction Hydraulic Setting Regulation Wedge systems is available on the QJ330, although there is a wedge system available on all of the Mid Range mobiles for setting regulations. The depth of the Jaw box is important with regards to mobiles. You need to be careful on the depth because we want to make the mobile until as low in height as possible for transport but the bigger depth of Jaw Box the better the material reduction due to the fact that the material spends longer in the crushing chamber.

Crushing concepts Machinery factors Jaw crushers Jaw tooth profiles Coarse Corrugated (CC) Sharp Teeth (ST) Heavy duty (HD) Designed to give high performance and low operating costs All jaw plates are reversible Wide Teeth (WT) Corrugated (C) Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Speed The number of compression and the distance material will fall is determined by the speed. We will examine this later in this module relative to cone crushers Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Throw Toggle plate angle Steeper angle resulting in larger horizontal movement Gap through which the material passes Sandvik Construction

Crushing concepts Machinery factors Jaw crushers Throw Toggle plate angle Adjustable stroke by changing the position of the toggle block holder. Dry rolling toggle (low maintenance) Sandvik Construction

Crushing concepts Machinery factors Cone crushers Chambers All other parts in the crusher are ”only” there to hold the chamber in place or to create movement of the mantle. Sandvik Construction

Crushing concepts Machinery factors Cone crushers Why so many chambers? All crushing starts with the chamber! Sandvik Construction

Crushing concepts Machinery factors Cone crushers Why so many chambers Which loaded EC chamber will produce the best performance Should both feeds be fed to the same chamber? Consider volumetric capacity Consider mechanical advantage Consider wear profiles Sandvik Construction

Each eccentric revolution means a crushing stage Crushing concepts Machinery factors Cone crushers Speed Eccentric throw m mg N mN Travel length Each eccentric revolution means a crushing stage Sandvik Construction Eccentric speed rpm H2800=395 H3800=360 H4800=320 H6800=290 H7800=280 H8800=230

Crushing concepts Machinery factors Cone crushers Speed There are a number of steps as material passes through the chamber When the falling stone is caught, it is trapped and to some degree pushed upwards. Sandvik Construction

Crushing concepts Machinery factors Cone crushers Speed Sandvik Construction

Crushing concepts Machinery factors Cone crushers Speed v Capacity Sandvik Construction

Crushing concepts Machinery factors Cone crushers Speed Practice proves theory Point go remember Higher speed: Lower throughput. Finer product. Improved product quality. Lower speed: Higher throughput Coarser product. Poorer product quality. Sandvik Construction

Crushing concepts Machinery factors Cone crushers CSS Consequence map C.S.S. reduction Smaller volume in the crushing chamber Higher pressure Lower capacity Risk of packing Improved shape More power Higher energy consumption Finer product Higher net capacity Sandvik Construction

Crushing concepts Machinery factors Cone crushers Motion pattern OSS CSS OSS Concave CSS followed 1800 later by OSS Mantle Sandvik Construction

Crushing concepts Machinery factors Cone crushers Throw Altering the eccentric throw Eccentricity Eccentricity Mainshaft Eccentric bush Eccentric Increasing the eccentric throw-more energy to the material-more capacity-more nett product Sandvik Construction

Crushing concepts Machinery factors Cone crushers Increased throw Larger avarage volume Eccentric throw Increased average chamber volume Small throw Large throw Increased throw resulting in increased chamber volume results in higher capacity more stones in the chamber to compress Sandvik Construction

Crushing concepts Machinery factors Cone crushers Throw alteration Consequence map Throw increased More crushing stone-against-stone Packing risk Higher capacity More power needed Higher power consumption Improved shape Higher net capacity Larger average setting Higher flow Higher torque Increased compression Sandvik Construction

Crushing concepts Machinery factors Cone crushers Larger throw larger crushing force F1+F2 F3 a Reaction Force F1 Hydroset pressure p is proportional to Crushing Force F Reaction Force F2 Area of Piston: A Reaction Force F3 Sandvik Construction

Crushing concepts Machinery factors Cone crushers Relationship between power & pressure Max permitted Packing Fine crushing Hydraulic pressure Coarse crushing Power Max permitted Sandvik Construction

Crushing concepts Machinery factors Cone crushers Take home message Best results are achieved when the optimum chamber is fitted to the crusher. The optimum throw has a major influence on obtaining best results 1&2 are volumetric issues and may well determine the utilisation of the crusher --- remember all crushers work best when continuously choke fed The crusher setting has an effect on both volume and reduction. Is the feed condition correct—have you removed the risk of packing Sandvik Construction

Crushing concepts Machinery factors Cone crushers Summary The work done in a crusher is affected by Machinery factors such as setting throw chamber volume speed Work done(energy)=volume x toughness x reduction ratio Sandvik Construction

Crushing concepts Machinery factors Cone crushers Summary Work done Machinery factors such as setting throw chamber volume speed Material factors such as toughness. feed size---product size. particle size distribution and specific gravity---bulk density---volume crushed. feed shape---moisture---clay content--- flowability. Work done(energy)=volume x toughness x reduction ratio Sandvik Construction

Crushing concepts Machinery factors Take home message All crushers have a volumetric and a mechanical limit Toughness of material, feed material particle size analysis, volume and reduction ratio all play their part in the ability of the crusher to perform the duty over an acceptable lifecycle. If any combination of these factors overstress the mechanical capability of the crusher (demands too much energy from the motor) it will be necessary to reduce the influence of another. Eg. The demand for greater throughput at the expense of reduction. Work done(energy)=volume x toughness x reduction ratio Sandvik Construction

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