Limitations on pan feeder size can cost mining operations to experience profit slumps. On reversing this undersized configuration, oversized feeders might maximize a mine’s productivity flow rate, but now there’s the very real possibility of a volumetric overload to contend with as the high-volume material throughput accelerates. Clearly, to keep the feed from causing a processing bottleneck, we need to properly size and select a pan feeder that’ll optimize aggregate flowrates.
Collecting the Sizing and Selecting Criteria
Neither too large nor too small, an optimally sized pan feeder maximizes flow efficiency. As a result of this process tailoring strategy, system downtime issues are happily reduced, too. The first job is to assess the aggregate stream, to evaluate its speed and material properties. Is the material dry and dusty? Is it wet and sticky? Is there a lot of undersized bits churning amongst larger groups of rocky matter? Maybe the whole aggregate flow is composed of heavy boulders. Next, just how dynamic is the material? Minimum and maximum flow rate velocities must be gauged at this point, for even a low-energy stream of undersized rocks will choke up a larger feeder if the material is flying fast. The shape, composition, mass, and gradation of the flow medium must all be identified and taken into consideration before a feeder can be selected.
Properly Addressing the Discharge Conditions
Now that the nature of the fast-flowing material medium has been identified, we’re halfway finished. The feeder dimensions are calculable, so the equipment receives a median capacity rating. However, there’s no way to know how the material is striking the “throat” of the feeder as it approaches the pan. To correct this issue, the designers need to assess a few additional feed variables. Namely, how is the hopper above the feeder pan guiding the abrasive material load? Ranked as a key design parameter, it’s the shear length of the hopper opening that regulates the aggregate as it’s funnelled towards a pan feeder. Shear length is described as the length of the opening hopper aperture. From the angled hopper maw to its strike-off bar, this value is used to control feed capacity.
And so it goes, with each dimensional constraint being carefully determined. The length of the feeder pan is such that it carries as much mineral load as possible. However, denser materials are clearly heavier, so this value can change. Shorter pans maximize space, but now there’s a chance of discharge-side self-flushing loss. Moving over to the drive system, an optimally configured VFD (Variable Frequency Drive) motor is locked to a gear reducer or hydraulically powered drive linkage. When the drive system and properly selected pan feeder kick in, they process mined feed without causing any kind of performance bottlenecks.