Exhaust capture and treatment from shake-out

The technique used for the emission collection from shake-out depends on the degree of mechanisation, the emissions to be extracted and the size range of the eastings, in particular the smallest and largest item cast on the same machine. 

The system of reducing emissions most commonly used is a ventilator panel on the side of the shaker. Usually, panels are installed on both sides of the shaker, regardless of the shaker size. If possible the rear of the shaker is enelosed in this way too. Frequently an extraction point is provided under the shaker in the sand-box, operating through a projecting pipe. This presents the risk of sand being extracted if the box is filled with sand up to the pipe. Moreover the pipe s inlet is often obstructed by sand lumps or adhering steam and dust. 

The best way of achieving good emission levels with relatively small ventilation rates is when shake-out is performed in enclosed units. Roof openings, possibly with a moving screen, doors and entry/exit chutes make it possible to use a crane or other means of transport. In addition, the closed cabins reduce the noise level. 

Appropriate techniques for dedusting are cyclones combined with wet scrubbers or dry filters. Biofilters are also used and are discussed in Section 4.5.8.6. 

For gravity die-casting and centrifugal casting, post combustion, chemical washing and adsorption to activated carbon are used in order to reduce organic emissions and odour. These systems have already been described above. 

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