The Problem

Part of a modernization project for Chino Mines Company involved new bins for copper concentrate, flux, and slag. Stearns Catalytic Corp., the engineering/construction contractor for the project, asked Jenike & Johanson to evaluate the design of the bins and feeding arrangement.

Our tests on the bulk solids showed that much steeper hoppers would be required to ensure mass flow. Without mass flow, semi-stable ratholes could form even when the moisture contents were low, causing erratic flow. If the moisture content increased above the specified value due to a disturbance in the dryer, arches and ratholing could be expected.

Jenike & Johanson's Solution

The solution we proposed was to modify the bins with a triple cone BINSERT® system as shown in the sketch. This converted the bins to mass flow, with no increase in headroom. Discharge is controlled by a mass flow screw feeder whose speed is varied by a signal from the impact flow meter.

The Result

Jenike & Johanson engineers performed the structural design calculations and prepared engineering drawings for the modification, including the mass flow screw feeders. We reviewed the bin and feeder construction in the fabrication shop and again on-site after installation to ensure that the design was properly executed. We also designed and supplied special shutoff slide gates to be used when performing maintenance on the bins.

The bins have been used for several years and have operated extremely well.

[ Complete Article ]

Email This Article