Heart of steel

When designing any mechanical conveyor system for the food, beverage, packaging or pharmaceutical industries, the big dangers to be considered are the potential breeding and the spreading of pathogenic micro-organisms. The pre-requisites, therefore, are easy-to-clean, non-corrosive materials free from potential dirt-collecting crevices. Another problem area is the lubricant; clean applications require either use of an expensive food-grade lubricant or lubrication-free chain.

There are a number of ways to achieve non-lube performance of drive chains which vary with the load capacity and life requirements of the transmission medium. Today engineering plastics, especially self-lubricating acetyl types, play a part but, in the main, such chains suit applications where corrosion resistance and weight saving are more important than load capacity. Where conventional externally lubricated steel roller chains are normally used, power transmission capacity and wear life are the main criteria for selection and an all-steel lube-free chain is required.

There are two main methods of achieving lubrication-free steel roller chain and both involve internal lubrication between the load bearing surfaces, between the chain pin, internal bushing and the roller. As the chain passes over a sprocket, particularly a driven one, it is these internal bearing surfaces that have to articulate under load. Given inadequate lubrication, these are the main areas of wear and the resulting chain elongation.