Routing Powder to Multiple Destinations in Mining & Mineral

A crusher, a mill or a reclaim conveyor feeds several destinations: a product silo, a reject bin, a blending bed. One line with a junction saves a great deal of structure, and the junction pays for it.

The physics is simple and unforgiving. Material travelling in a straight line has to change direction, and it does that by hitting something. In abrasive mineral service that impact point erodes quickly, and once it has eroded through the liner it erodes the body, at which point the repair is a fabrication job rather than a liner change.

Jamming is the second mechanism. A diverter sized on the nominal particle distribution meets a lump from a damp bin or a tramp piece from upstream maintenance, and the blade or plug stops halfway. A partially switched diverter sends material to both destinations, which in a plant where one of them is a reject bin is a quality problem as well as a mechanical one.

And the tonnages are large, so a junction that leaks across the closed branch moves material where it was not wanted at a rate that shows up in the stockpile rather than in a sample.

A junction whose wear is concentrated in a replaceable liner at the impact point, with a measured service life and the liner on the shelf before it is needed.

An opening and a mechanism sized for the largest credible particle, so a lump stalls the feed rather than the diverter.

Positive sealing across the closed branch, confirmed by position sensors, so the destination is known rather than probable.

In a pet food plant the same junction fails hygienically rather than mechanically: a fat layer on the seal face carries one recipe into the next.

The impact point is identified first, because it is not always where the drawing suggests. The particles carry their momentum into the outer wall of the turn, and that is the surface to line: ceramic tile or hard faced plate where the angle is steep, a compliant rubber where the material grazes.

Access to that liner is then designed. A junction that has to be cut out to be relined will be run until it leaks, so a bolted access panel at the wear face is worth more than a harder liner behind a welded one.

Sizing follows the top particle rather than the distribution. That includes what the screens pass when they are worn, and it includes the tramp material the plant actually sees. Where jamming cannot be designed out, a stall detection on the actuator is better than a torque setting that bends the blade.

Switching is sequenced at rest, with the feed stopped and the line cleared. A diverter asked to cut through a flowing stream of abrasive mineral will do it a few times and then stop sealing.

• Impact point identified and lined as a wear part with its own service life.
• Bolted access at the wear face so relining does not mean fabrication.
• Opening and mechanism sized for the top particle and credible tramp material.
• Switching only with the feed stopped and the line cleared.
• Stall detection on the actuator rather than a torque setting that deforms the blade.
• Position confirmed on both ends, since leakage across a closed branch shows up in the stockpile.

• Abrasiveness and impact angle at the junction, which decide the liner material more than the mineral name does.
• Top particle size and credible tramp material, which set the opening and the jam case.
• Access for relining, which decides whether the liner is a consumable or the whole junction is.
• Consequence of a misroute, which is high wherever one branch is a reject or a different grade.
• Moisture content, since damp mineral builds up on a stationary blade and seat.
• Tonnage, because a small cross leak at these rates is a measurable misplacement of product.