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How Vertical Shaft Impactor Works?
Vertical Shaft Impactor is no more than Centrifugal "STONE-PUMP". Stones are fed into rotor center (such as water in the centrifugal pump) & stones are thrown outwards towards the boundary by outward-developing force.
Feed material is fed through a vertical tube in the midway of the horizontal rotor revolving at high speed (60 M/Sec to 70 M/Sec) around an axis in vertical motion. Feed material owing to the centrifugal force starts gaining speed and it acquiring distributed over the cone of the distribution and as the material travels over the vanes of the rotor, towards the periphery matches the same as the speed of the periphery of rotor. At the instant of rotor alighting, material achieves a velocity which is the sub-sequence of radial velocity and peripheral velocity (owing to centrifugal force) and resultant velocity direction is almost 45 degrees to radial direction.
These feed particles have so high kinetic energy that after impact, against the stresses of breaking surfaces generated within the particles overshoot their optimum strengths and hence particles disintegrate into different number of pieces giving rise to fresh surfaces.
It is the velocity and only the velocity which decides the Fragmentation amount.
Hence, Vertical Shaft Impactor is in true sense a purity defines Impact Crusher which crushes only by the way of Impact. Not like other traditional Impact Crushers, where shear, attrition, compression and impact allocations, play the part in material crushing.
There is no gap setting in Vertical Shaft Impactor. Crushed material falls outside of the annular open ring area by the way of gravitational force.
We manufacture both types of Vertical Shaft Impactor:
Stone on Stone type: Rotor is designed in a manner that, stone layer gets settled on the vane and surface is also developed by material built up. Thereby minimizing the deterioration on the vanes & also on walls' breaker. But this cushioned surfaces, minimize a considerable crushing amount and the spare consumption amount is also minimized.
Stone on Steel type: In this category of VSI, after getting discharged from the rotor, the material slides on the metallic steel vanes and hits on the surfaces of metallic steel. By nature wear on, breaker surfaces and vane surfaces is high. Larger feed sizes up to 100 to 150 are possible. Ratio to reduction is also high.
Points to Remember
There should be a clear under standing that Stone-on-Stone V.S.I is mainly a "Shaping Machine" and not a harsh heavy reduction machine for crushing. Heavy size reduction has been avoided by intention in Stone-On-Stone V.S.I, by offering a "Soft Cushioned Impact", so that, material is not minimized to ideal product size at one go, but it achieves the desired size of product, only after three to four passes or more, This has been done by intention.
Hence, quite a high recirculating load was needed. And that is how cubical shape attained by nine stone-stone type V.S.I, is very much advanced to cubical shape received by any other present I crushing equipments.
So, capacities of throughput are extremely high and should not be confounded with the ultimate capacities of product output. Invariably throughput capacity needs to be 1.5 to 5 times of output capacities. For example, sand manufacturing Vertical Shaft Impactor having output capacity of 20 TPH, should have a say of 100 TPH capacity of throughput.
Hence, capacities of recirculating equipments and feeding equipments should be dependent on throughput capacities and not on capacities of output.
Making sure that no over sized material is fed to Vertical Shaft Impactor, is very important. Even occasional, two pieces or one piece can be harmful, as these pieces may choke up in the tube of feed or block the rotor passage. Rotor will become out of balance and if continued to operate further may get damage to the bearings. Therefore, per-screening before feeding into V.S.I, is very necessary. Even papers, cardboard pieces, cotton waste and clay lumps, etc., may block the passages. Upper limit of feed size, which is maximum feed size should be controlled in a very strict manner.
Continuous feeding, without disruption at rated throughput capacity provides the best results. It enhances shape and outputs of aggregates, gets improved further.
Surface velocity of the rotor determines the ratio of reduction. For finer end product, higher speeds are needed. For standard aggregates, 45 m/sec is optimum speed but for better products higher speeds even up to 70 m/sec to 80 m/sec are utilized.
It is highly advisable and advantageous to make provisions in the circuits of crushing, in a manner that all the detached sizes in needed proportion you should be able to convey back to Vertical Shaft Impactor, in order to improve shape further and to attain desired analysis of grain in the product. (You could say to attain desired F.M.).
As the material is all the time flowing over the bed of material and impacting also impacting on the built-up of material, wear & tear on the components is minimized & hence per ton spare parts consumption entire production is very low; most commonly when compared with traditional impactors.
Crusher Dimensions in mm
|Max. Feed size||0-30||0-35||0-35||0-40||0-40||0-50||0-50|
|Diameter in mm||610||780||780||1000||1000||1200||1200|
|Surface speed m/sec||30-62||45-65||45-65||45-65||45-65||35-55||35-55|
|Power in KW||55||75||90||160||200||250||300|
|Wt. in Kgs. approx||2800||3200||3800||5800||6000||6900||7000|
Production Capacities (depend on material & feed size, approx valuse)
|Type||Through Put||Product Through Put|
|0-2 mm||0-4 mm|
|35||40 tph||8-12 tph||15-20 tph|
|55||70 tph||12-16 tph||20-25 tph|
|80||90 tph||16-24 tph||23-30 tph|
|110||130 tph||25-30 tph||35-40 tph|
|160||160 tph||30-40 tph||50-70 tph|
|220||220 tph||50-70 tph||70-90 tph|
|330||280 tph||70-90 tph||110-130 tph|
Closed Rotor (Welded Construction)
Open Rotor (Bolted Construction)
Tips life with different application.
Product - 0-4
|Mineral with 15%Quartz||1500-1300|
|Mineral with 60-90% Quartz||500-1500|
|Blast Furnace Slog||3000-4000|
Above Non-binding values differentiate considerably.
Payment Term : 40% Advance, Balance against Proforma invoice