The VSI-800-CR Vertical Shaft Impact Crusher, also known as a sand-making machine, is a twin-motor final-stage crusher for manufactured sand and fine cubical aggregate. The following covers feed materials, output products, applications, wear-part service, the rock-on-anvil principle and comparisons with alternatives.
What materials can the VSI-800-CR process?
The VSI-800-CR is built for the fine fractions coming from secondary crushers, including hard, abrasive stone. Typical feed includes:
- Basalt, granite and other hard igneous rock
- Hard limestone and gravel from secondary crushing
- Material requiring conversion into manufactured sand at higher tonnage
Maximum feed size is 40 mm. The closed-rotor, rock-on-anvil configuration is specifically matched to harder rock, where impact against the anvils gives a stronger, more consistent reduction.
What products does it make?
The VSI-800-CR produces manufactured sand and cubical fine aggregate. Output is used as a sand substitute or supplement in concrete and asphalt, and to upgrade the shape of fine aggregate from upstream crushers. The high-velocity impact creates a high fines content and a cubical grain shape that improves the workability of bound mixes.
Which industries and applications use it?
- Manufactured (crushed) sand production for concrete at medium-to-large plants
- Fine aggregate shaping for asphalt and concrete
- Quarrying and aggregate plants supplementing or replacing natural sand
- Hard-rock processing where a substantial, continuous sand output is required
What is the difference between rock-on-anvil (CR) and rock-on-rock (OR)?
In the rock-on-anvil (closed rotor, CR) configuration of the VSI-800-CR, material is thrown by the rotor against fixed steel anvils. This gives a stronger reduction and a more consistent product and is preferred for harder rock. In a rock-on-rock (open rotor, OR) configuration, material is thrown against a bed of the same stone, which lowers wear-part consumption but generally yields a slightly different product mix; it is favoured for very abrasive feed where wear cost dominates.
How are wear parts replaced and how long do they last?
The main wear parts are the rotor wear tips, the anvils and the chamber liners. In the rock-on-anvil configuration the anvils take the direct impact and wear faster on abrasive feed, so they are designed to be interchangeable and replaced on a routine schedule. Service life depends on rock abrasiveness, rotor speed and tonnage; at the VSI-800-CR's higher throughput, wear-part planning is part of normal plant operation.
How does a VSI compare with a tertiary impact crusher?
A tertiary impact crusher uses a horizontal rotor with blow bars and breaker plates and gives strong reduction with cubical shaping for non-abrasive stone. The VSI-800-CR accelerates material against anvils and is the better choice for manufactured sand from harder, abrasive rock, with rotor speed giving precise control over fines. For abrasive feed and a sand product, the VSI is normally preferred, and the two machine types are often combined so the tertiary impactor shapes the coarse fractions while the VSI generates the sand.
How does the VSI-800-CR fit into a complete plant?
The VSI-800-CR is installed after the secondary crusher in the sand circuit, fed from a screen that delivers the correct size fraction. Its output is screened again and, where a washed product is required, passed to sand-washing equipment. The variable-speed rotor lets the operator match the fines yield to demand, and the twin-motor drive sustains the throughput a mid-to-large plant requires. The unit is supplied within complete CONSTMACH plants or as an addition to an existing line, with wear parts available from the manufacturer.
