Rotofeed®

Rotofeed® systems normally consist of two pressure vessels, with the upper Lock Vessel being used to gravity feed material at pressure into the Dispensing Vessel which is always pressurised.  The material is fed out of the Dispensing Vessel by the Rotofeed® Dispenser which is driven by a variable speed electric motor and very accurately delivers the material into the pipeline where it is transferred in a continuous air stream into the process. The use of the variable speed motor allows the feed rate of the system to be turned up or down as required, and the Rotofeed® System has generally a 10 : 1 turn-down ratio. Occasionally, variable speed metering screw feeders are also used to effect the transfer into the air stream, and this technology was the first to be used by Clyde Bergemann Materials Handling. The Rotofeed® Dispenser is a Volumetric device, and with homogeneous consistent materials can offer an accuracy of feed rate in the order of + 2 ~ 3%.  More accurate Gravimetric control of the feed rate can also be offered by the use of load cells. By using only the Dispensing Vessel, the Rotofeed® system can be used to deliver measured batches of material into the process, before stopping to allow the vessel to be vented and re-filled. The air supply is normally from a directly coupled medium-pressure air compressor, using hot conveying air. Pipeline sizes are not matched to the Rotofeed® sizes, and are dependent only on the transfer distance and available air pressure. The Rotofeed® system has a transfer rate limitation of 100 tonnes/hr, over distances up to 300 metres.  Transfer velocities vary from 7 ~ 20 metres/sec, and transfer pressures up to 30.0 bar(g). The Rotofeed® technology has applications in the injection of coal, other fuels, limestone and bed sand into the re-injection of ashes and grits into Fluidised Bed Combustors, the injection of limestone into FGD Processes, and any other applications where direct material feed into the process is required.