Sandvik Mining and Construction

Narrator: This presentation explains the basic functions of how the Sandvik VSI Autogenous crusher works. This is a rock on rock (autogenous) crusher, whereby no wear parts are used to crush the rock.

Sandvik Mining and Construction

Narrator: Look at the image showing the main parts and basic function of a VSI crusher. A VSI is typically a third stage crusher (maixmum feed size is 55mm) and crushes rock by the impact of rock agianst rock. The VSI works by accelerating rocks using centrifugal force, to a very high speed and then impacting them into each other within the crushing chamber. Click on the link opposite to see the basic functions of the Sandvik VSI crusher.

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Sandvik Mining and Construction

Narrator: Crushing is achieved by feeding the rocks, via gravity feed from either a conveyor or feeder. From the moment of entry into the feed hopper, rock ledges are formed within the crusher, which protect the crusher and guides the flow of material through the crusher and onto the discharge conveyor. Click on the link to see the flow of material through the crusher.

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Sandvik Mining and Construction

Narrator: The high speed rotating rotor is the heart of the crusher. This rotor acts as a rock lined centrifugal pump. Click on the links below to see a sectioned view of the rotor in action.

Click here to see rotor with feed

Click here to see rotor without feed

Sandvik Mining and Construction

Narrator: The rocks are accelerated by centrifugal force to typically 53 metres per second - that’s 190 kilometers an hour or around 118 miles an hour.

Sandvik Mining and Construction

Narrator: The chamber inside the VSI is cleverly designed so that it always keeps a layer of rock on its surface. Therefore the rocks that have been accelerated from the rotor are impacted into other rocks within the crushing chamber – this protects the machine parts from wear. The highly energized rocks within the crushing chamber, impact and move in a helical path around the crushing chamber in the same direction of the rotor. This gives multiple breakage by impact, attrition and cleavage. Click on the link to see the rock acceleration and movement in the crushing chamber.

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Sandvik Mining and Construction

Narrator: A Sandvik VSI also has what is called Bi-Flow system. The Bi-Flow rocks pass through adjustable gates within the feed hopper and are directed to fall into the crushing chamber, but in the opposite direction of the rotor fed material. Here they combine with rocks that are being accelerated out of the rotor. Bi-Flow can increase the crushers capacity by around 20%, without reducing crusher efficiency. Material in Bi-Flow is indepedant from the rotor (and motor power) and therefore requires no energy input and causes no increased wear to the rotor wear parts.

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