Prepare for the Worst But ...
In this issue of Process Heating, we bring you several articles that should help you do just that when faced with highly corrosive process fluids or environments, unexpected dryer conveyor bed contortions, the need for heat transfer fluids, or reduced fan airflow due to system effects.
In “Engineering Graphite: Equipment for Corrosive Applications,” Kevin J. Kelley, director of sales and marketing with SGL Carbon Technic LLC, Strongsville, Ohio, a manufacturer of carbon-based products including graphite heat exchangers and pumps, notes that graphite process equipment, especially heat exchangers, are increasingly being used in chemical processing, pharmaceutical and other process applications requiring high corrosion resistance. Impervious graphite resists most concentrated acids such as hydrochloric, hydrofluoric, phosphoric and sulfuric acids; pickling liquors; and aqueous solutions containing halides, nitrates or sulfates. In addition, its corrosion resistance at temperatures to nearly 400°F (200°C) makes it suitable for many heat processing applications.
Conveyor dryers have only a few moving parts, and the most important by far is the conveyor bed. In “Conveyor Bed Dryer Maintenance Tips,” Steve Blackowiak the manager for parts and refurbishments at Aeroglide Corp., Cary, N.C., a manufacturer of conveyor-based dryer and oven systems, offers tips to help you prevent a major bed crash. Among the factors to consider are proper belt tensioning, conveyor chain wear, conveyor sprocket wear and belt lubrication.
In “Choosing Heat Transfer Fluids,” Michael Bates, technical director for Duratherm Extended Life Fluids, Lewiston, N.Y., a manufacturer of heat transfer fluids, offers a general overview on the two main culprits of fluid breakdown -- oxidation and thermal degradation -- as well as fluid types. Of course, before selecting any fluid, consider the expected lifespan of your heat transfer fluid system, application-specific criteria such as whether a food-grade fluid might be required and environmental issues.
Understanding some of the common causes for system effect losses can help you more accurately size and select fans. Provided by Willowbrook, Ill.-based New York Blower Co., “Flow Effects” explains how when specifying fans, you must look beyond the routine system resistance calculations and consider the location of some common components and their proximity to the fan inlet or outlet. Elbows or poorly designed fan inlets, for example, can create additional immeasurable losses commonly called “system effects.” If they are not eliminated or minimized, the fan speed and horsepower will need to be increased to compensate for the resulting performance deficiencies.
Using these technical articles as well as our online archives at www.process-heating.com, which includes a Google search of more than 10 years ofProcess Heating, will help you know what the worst might be while you prepare for the best -- and get it.
Associate Publisher & Editor