Load & Haul

Intelligent VSI design cuts costs for high quality sand

In addition to an aggregate plant, the Chung Kang Aggregate Enterprise site in Taichung, Taiwan, incorporates a plant that produces high quality sand for use in road construction and civil engineering work. The material is produced from crushed gravel with a work index of 20 and abrasion index of 0.57.

The material is in great demand, as Taiwan suffers from frequent earthquakes, which additionally means specification on the concrete used in buildings and bridges must be of very high quality. For this reason, the sand used must be produced in a vertical shaft impact (VSI) crusher to meet the required standard.

Chung Kang had been operating two VSI crushers, each with a power of 220kW. These two machines produced 30 tonnes per hour of 0-5mm sand of a satisfactory quality but the cost per tonne was deemed unacceptable by the business, and a new solution was sought.

After discussing its requirements with Sandvik Construction, Chung Kang replaced its two VSIs with a new Sandvik CV218 VSI crusher.

Impressive results

Based on site visits and analysis of the material and the production processes, Sandvik’s technical team could assure Chung Kang that the CV218 VSI crusher would produce a minimum 60 tph of 0-5mm sand.

After installation and testing, however, the Sandvik VSI exceeded the initial assurance, producing an average 70 tph of 0-5mm sand.

In addition to this boost in production, the business experienced a significant reduction in operating costs and emissions. While the old installation involved two 220kW machines, the single CV218 plant used 220kW to produce a higher throughput, considerably reducing the cost per tonne of Chung Kang’s operation, and saving energy.

Not only was production significantly improved from 30 tph to 70 tph but the quality of the aggregate was also enhanced. This allowed Chung Kang to sell an additional product of 5-13mm, which benefited the company by commanding a high price.


Customer-focused features

The CV200 series – provides a range of benefits over other autogenous VSI crushers, making it suitable for many applications, including manufactured sand, premium shaped aggregates, and recycled aggregates.

Introduced in 2002, Sandvik’s line of autogenous crushers – of which the CV218 is but one model – utilise rock-lined rotors to accelerate material. This is then impacted in a highly energised rock-lined crushing chamber, which again impacts with material falling through the patented bi-flow system.

The autogenous crushers incorporate the Sandvik Hurricane rotor. Dubbed a “major breakthrough in VSI autogenous rotor design” due to its decreased vibration levels and wear part design, the rotor increases crusher bearing life and reduces maintenance.

These factors contribute greatly to improved production and lower operating costs.

Operator safety has also been accounted for, as standard Sandvik VSI crushers are fitted with a timed, trapped two-key system, which ensures the safety of maintenance personnel, combined with electrical isolation. Also supplied, and fitted as standard, are a vibration detection switch and a pre-start alarm siren.

The CV218 used by Chung Kang is a single drive crusher with a 220kW electric motor, complete with an automatic grease lubrication system and hydraulic tension of the V-belts.

Source: Sandvik Construction

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