Plant Services - May 2008 - (Page 48) Power transmission reliability Chain manufacturers also produce a large number of special conveyor chains. Many of these run over standard sprockets but use special lubricants, coatings, materials and design features to provide longer service life in adverse conditions. When chain features are well matched to the application, these specialized chains often are well worth their added cost. But, in many cases, properly lubricating and maintaining a standard chain in service will be more economical in the long run. Align during installation Many manufacturers provide good installation guidance. The book, “Standard Handbook of Chains,” by the American Chain Association, gives more information. These usually have only the basics. A few steps need extra attention. Align the sprockets and tracks, or ways, correctly. Align the head shaft and tail shaft sprockets with each other as closely as practical. Use standard laser alignment to ensure the tracks are well-aligned with the sprockets, but using piano wire also works well. Ensure that the shafts are perpendicular to the chain path. This is especially important with multistrand conveyors that have chains some distance apart. If the conveyor is heavily loaded, verify the alignment under load because high loads can flex machine parts. Multiple chains intended to run in parallel often are supplied in matched sets. Be sure to install them in the correct order to avoid erratic operation and breakage. Set the initial tension correctly. Chains that are too tight can run hot and wear faster. Chains that are too loose can be noisy and operate roughly. If the conveyor is to operate heavily loaded, ask the supplier for data showing how much the chains elongate with load. A heavily loaded chain might elongate so much that it becomes loose. That is possible even if the initial chain tension is set correctly at idle. Lubricate along tracks Conveyor chains must have proper lubrication to achieve long and reliable service. Proper lubrication between sprockets is often more important than when the chain engages the sprockets. While it’s obvious that sliding-surface Ranges and grades Temperature range (°F) -50 to +50 -20 to +80 +10 to +110 +20 to +130 +30 to +140 +40 to +150 Suggested viscosity grade SAE 5 SAE 10 SAE 20 SAE 30 SAE 40 SAE 50 Table 1. Suggested oil viscosity as a function of operating temperature. When the temperature range permits a choice, use the heavier grade. 48 www.PLANTSERVICES.com May 2008 http://www.tdcflltar.com http://www.PLANTSERVICES.com
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