Feeder breakers and feeder/sizers are both used as primary crushing options in run-of-mine (ROM) coal crushing operations, however there are a number of reasons why the feeder breaker has become the ROM crusher of choice in coal.
“The feeder breaker is modern, efficient and maintenance friendly,” said McLanahan coal applications and product specialist Brad Anstess.
The feeder breaker is a feeder and crusher in one compact, low-profile, horizontal unit. While a feeder/sizer arrangement uses two different pieces of equipment for the same function, requiring additional structure and civil.
The feeder breaker has a number of advantages over a feeder sizer arrangement, including lower capital and infrastructure costs. Because the feeder breaker has a feeder and crusher in the same horizontal plane, there is no need to raise the hopper and therefore ROM dump wall up by an additional three or more meters, or to make the feeder excessively long and angled because it does not need to feed into a primary sizer chute.
Similarly, operational, maintenance and running costs are lower when selecting a feeder breaker over a feeder sizer combination. These cost reductions result from its smaller vertical and horizontal footprint as no primary sizer structure, access platform or maintenance area required. Feeder breakers also offer reduced power and have less moving parts, along with reduced spare part crushing component costs when compared to a primary sizer.
Feeder breakers are also able to adjust product size by raising or lowering the crushing head, unlike a fixed centre sizer which cannot be adjusted in this way. The crushing picks used in a feeder breaker are designed to selectively crush coal and rock in a shear, taking advantage of coal’s weaknesses, cleats and fracture planes, unlike a primary sizer with its block faced tooth profile.
When a feeder and sizer option is used the feeder in most cases would have to be longer and angled to accommodate the sizer it has to feed. Lost hopper capacity would also be an issue as it would need to be longer to accommodate the sizer, resulting in a longer chain with its own additional costs.
McLanahan feeder breakers feature material-specific lacing patterns within the pick design; large diameter crushing rolls that are specifically designed to efficiently crush the maximum feed lump size and maximise unobstructed throughput of undersize particles; and picks positioned on different diameters and splayed horizontally to ensure maximum crushing efficiency and to prevent ‘grinding’ on oversize lump.
“The McLanahan feeder breaker is designed for today’s time poor market,” said Anstess.
Unique features provided in the McLanahan feeder breaker include a hydraulically operated rear door which provides clear and open access to allow efficient emptying of the hopper, and easy access for maintenance. The Feeder Breaker also includes hydraulically powered chain tensioning, plug welded and bolted liners for efficient removal of wear liners and large access doors along both sides of the feeder frame to enable swift and safe access to chain pins and links.
The specially designed front access door doubles as a safe work platform when lowered into maintenance position to enable work to be carried out on the breaker head and feeder head shaft sprockets whilst access is still available from the rear.
“Nowadays”, said Anstess, “It is pretty standard to include a range of sensing and condition monitoring devices and data logging on all mining equipment to maximise the ability to track and report on the machines operating parameters at all times.”
We find that it is valuable to offer different level condition monitoring packages for different client’s needs. Customising a feeder breaker for each site uses standard components but optimises the design so that the client is not compelled to pay for features that are not relevant.