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Rodless cylinder takes over sludge-raking chore

Pressure decay circuit
Pressure decay circuit automatically reciprocates long-stroke rodless air cylinder.
External yokes
External yokes on DGO rodless cylinders are linked via powerful rare-earth magnets to internal air-driven pistons.

Wet aluminum hydroxide sludge is a byproduct of our anodizing process. After drying, we dump the sludge in a bin from which it is eventually hauled away for disposal. To reduce the volume — and thus the hauling charges — we had been raking the material manually, but because the sludge is usually hot and frequently fuming, this was an unpleasant and laborious chore.

A few years ago we eliminated the human factor with an automated system that uses a DGO rodless pneumatic cylinder from Festo Corp., Hauppauge, N.Y., to power the rake. The 12-ftstroke cylinder mounts on a framework along the longer side of the rectangular bin and is reciprocated by a simple pressure- decay air circuit. The rake is attached to a swing arm mounted on the cylinder’s yoke. After we learned that the circuit performs best when the 4- way valve exhaust ports are choked to provide sufficient backpressure, the system has run without problems.

Matthew Chan
Dan Martina
Kawneer Co. Canada Ltd.
Scarborough, Ontario