A Chocolate Flavored Gearbox (just in time for the holidays!)
Q: A chocolate factory called us with an unusual problem. A seal on a mixer gearbox was failing, with chocolate powder getting into the oil. Was this going to harm the gearbox?
A: The short answer is yes, the chocolate powder will harm the gearbox. How much harm depends on what point in the process the mixer gearbox is located (See Fig 1). At the early stages, some of the cocoa bean shells are present in the mix before winnowing, and if these make it into the oil, abrasive wear will occur. At later stages of production, (liquor or crumb phase) the chocolate can easily mix into the oil, the immediate result being an unacceptable increase in viscosity. In addition, the chocolate mix will interfere with the heat transfer capabilities of the oil. Additionally, the film strength characteristics of the oil will be affected , resulting in greater tooth wear. Finally, this is a food grade oil in a food grade environment. The leaky seal may allow oil to get into the chocolate product, ruining the batch. The recommendation to the company was to change the oil, and fix the seal as quickly as possible.
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Figure 1 - Chocolate making schematic (Ref: www.fieldmuseum.org/chocolate/making.html)
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-DPW
