Improving the Capture of Dust for Sand Moulding Application
Sand is used to form moulds into which molten metal is poured to make castings. The sand forming the mould is given strength by adding a binder which may be a resin or clay. After the casting has solidified, the metal component is released from the mould at the “shake out”. The sand is then reclaimed and reprocessed to allow for its repeated use. The recovered sand may be crushed, cooled and graded as part of the reprocessing. It will be handled on conveyor belts, and probably an elevator returning the sand to silos or hoppers for re-use. Throughout the process, dust is released and there can often be visible water vapour for clay bonded sands. Historically a wet scrubber was the automatic choice for this application because of residual moisture and visible water vapour which precluded the use of a bag filter. However the increasing use of chemically bonded sands means that a cartridge filter such as an AAF OptiFlo® RC – when carefully applied – is often the first choice.
Our client wanted to improve the capture of dust that was created and/or released during the handling of recovered sands on conveyor belts. There is a potential for dust to be created at each change of direction, chute and belt transfer and its thought that as much as 1% of product stream is becoming airborne during its transit through the client’s complex materials handling system.
AAF proposed an OptiFlo® RC with an integrated fan and isolation box to meet the challenge. This pulsejet cartridge dust collector is specifically designed for the handling of dust generated by sand moulding and provides a continuous operation. The OptiFlo® RC was supplied with REDClean® NFR cartridges. AAF cartridge technology allows operators to reduce power consumption, enhance efficiency and extend the time between cartridge change-outs. AAF also suggested hooding is employed at each transfer point with special attention to elevators or chutes where “natural windage” can create airflows that must be allowed for in the selection of the extraction system flow rate.
The installation of the OptiFlo® RC dust collector has ensured the removal of airborne particles and made the plant a safer environment overall. Since the successful commissioning of this dust collector, it has performed to the high standard expected by the client, prompting them to choose the OptiFlo® RC for their other facilities.