Keeping oven chains protected, even at extreme temperatures
Bakery ovens used in the production of tortillas, pitta bread, pizza dough and other baked goods can expose conveyor chains to extreme temperatures upward of 650°C. At these high temperatures common foodgrade chain oils can evaporate and break down, leaving behind high levels of residue and/or requiring constant re-lubrication.
A common solution to this is to use a chain lubricant containing suspended industrial solids that will provide emergency lubrication even when the carrying fluid evaporates, but these formulations are often at the expense of the lubricant no longer being registered by the National Sanitation Foundation (NSF) as food grade (H1). So how can you ensure high-temperature performance whilst maintaining food safety standards?
Firstly, it's important to recognise that technical advances in the industry show that H1 lubricants can now deliver the same, if not better performance than conventional industrial products. In the bakery industry NSF H1 lubricants can be used safely on machinery components such as pumps, mixers, gearboxes, chain drives and conveyor belts. Even at high temperatures, heavily loaded and in wash-down environments, the appropriate NSF H1 lubricant will still reduce friction and wear, protect against corrosion, dissipate heat and have a sealing effect.
Secondly, there is a requirement to understand the make-up of the lubricant being applied to any equipment, especially when operating at elevated temperatures as the various base oils used in lubricants have different temperature limits and exceeding these limits even by a small amount; can have a dramatic effect, resulting in evaporation and the formation of residues. Even synthetic esters, which are excellent performers in many bread ovens can evaporate at temperatures above 260°C - 315°C resulting in frequent re-lubrication in order to keep the chain lubricated and protected. Even with constant re-lubrication, however, the continuous breakdown of certain types of base oils can thin the lubrication barrier reducing component protection and, as residue levels become higher, the result is an impairment of fresh lubricant reaching the intended surface(s).
To counter this, a common solution is to use a solid lubricant. The solid lubricant is suspended within a fluid carrier which, when applied, carries the complete formulation into the components, as this begins to evaporate at higher temperatures the solid remains inside the friction points as a type of emergency protectant to decrease wear of the surfaces.
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