Overcome crushing challenges with FLSmidth® EV Hammer Impact Crusher
Overcome crushing challenges with FLSmidth® EV Hammer Impact Crusher

Overcome crushing challenges with FLSmidth® EV Hammer Impact Crusher

Maximises crushing of large feed blocks.

Many cement plants extract limestone by blasting, which often leads to oversized boulders containing a lot of clay and sand. The crusher therefore must handle feed that contains larger blocks as well as some sticky materials. FLSmidth EV Hammer Impact Crusher is a proven, reliable and cost-effective impact crusher that help to overcome these crushing challenges.

In traditional hammer crushers with a top inlet, introducing large blocks in the feed can impede the action of the hammers and block the crusher. FLSmidth EV Hammer Impact Crusher reduces quarry-size limestone boulders of size up to 2.5 m and 5 tonne to mill feed of 25 mm in a single operation. This is a reduction ratio of 1:100 in a single operation.

High Capacity
The EV Hammer Impact Crusher throughput capacities range up to 2,200 tonnes per hour (tph) with outlet grate and 2,500 tph without outlet grate. Motor sizes are typically in the range of 500 - 2,500 kW. Featuring a horizontal feed system, EV Hammer impact crusher is ideal for crushing abrasive and moderately sticky raw materials.

Highly-effective prime crushing The EV Hammer Impact Crusher features a highly-effective two-stage crushing process. Primary crushing takes place by impacting. Secondary crushing takes place by shearing and compression between the impact hammers and the breaker plate and between the hammers and the outlet grate. This ensures that even the smallest particles absorb energy and that no oversized particles leave the hammer impact crusher.

The horizontal feed system can also tolerate coarse feed blocks because of its shock-absorbing inlet rollers.

Hammers arrangement increases efficiency
The hammer rows, are arranged in staggered pattern to provide complete coverage across the outlet grate. By arranging them in this way, the raw material can be crushed at multiple points increasing overall efficiency.

The symmetrically-shaped hammers are free to pivot around the bolts, reducing the impact from the contact between material and hammers, thereby protecting the rotor and crusher housing.

Adjustment of the spacing between the hammers, breaker plate and outlet grate can be optimized to compensate for hammer wear. Even when the hammers lose up to 30 per cent of their original weight, the required product size curve is unaffected. The hammers can easily be turned to reverse the leading and tracing edges for maximum service life.

"Grate" expectations fulfilled
The adjustable outlet grate gives the EV Hammer Impact Crusher control of the maximum size of the product. The grate ensures a consistent flow to the conveyor and protects it against any sudden impact of material leaving the impact crusher at high speed. Equipped with sturdy, replaceable grate bars supported by heavy cheeks, the adjustable outlet grate allows unique control of the mill feed size using hydraulic systems.

The outlet grate also serves as protection for the conveyor and other machinery such as reclaimers, sluices and mills, against operational upsets and mechanical damage The hold-up mechanism of the outlet grate generates a crushed product with a relatively high proportion of fines. In this way, more of the comminution work is moved from the less energy-efficient raw mill to the more energy-efficient hammer impact crusher.

Durable and Reliable
All exposed surfaces in the crusher including the adjustable breaker plates are lined with bolted-on wear-resistant plates.

The inlet rollers consist of a cylinder and a concentric shaft which is driven by a separate motor. Rubber pads inserted between the shaft and the cylinder make the rollers shock absorbent.

The hammer rotor assembly consists of a heavy-duty, forged shaft with a square cross-section and fitted with rotor discs. The special "sandwich" assembly of the discs is a robust construction which prevents distortion and crack formation.

Crusher retrofit
Since FLSmidth first launched the EV Hammer Impact Crusher in the mid-fifties, design improvements have continuously been introduced while its basic concept has remained the same.

Many of the improvements have been based on the day-to-day experience of operators. The improvements can also be implemented on existing crushers to upgrade their operation and facilitate daily maintenance.

It will normally be practical to implement such an EV Crusher retrofit, including new hammer rotor and outlet grate, in connection with a scheduled major overhaul of rotor and grate.

Main benefits of EV Crusher retrofit:

  • New Crusher in a week
  • Capacity increased upto 10 per cent
  • Specific wear rate (g/t) reduced
  • Specific power consumption (kwh/t) reduced
  • Wear parts last longer
  • Less downtime
  • Low maintenance with facilitated tools
  • Low TCO
  • ABOUT THE AUTHOR:
    J Raghuraman, Product Line Manager-Material Handling, FLSmidth.

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