In this issue of Process Heating, we focus on fundamentals with articles that cover the basics of finned-tube coils, microwave heating, infrared thermometers and drying effusivity.
In "Coil Capacity and Efficiency," Matthew Jacobs of MultiTherm, Devault, Pa., notes that finned-tube coils are found in many process heating systems and many times are the first major component to show symptoms of improper upstream filtration. In a dirty atmosphere, they can actually cause many systematic problems, including pump, compressor and fan failures. Jacobs covers the causes of air-side fouling and offers tips on keeping your coil clean and operating efficiently.
Microwave heating is the focus of two articles. First, in "Food-Friendly Heating Boost," Gene Eves of Ferrite Co. Inc., Hudson, N.H., and Phil Weiner of Philip Weiner Associates Inc., Grand Rapids, Mich., explain how incorporating a microwave booster oven with your existing convection system can increase production capacity. Booster ovens can be used to preheat product centers before passing the product through the primary heating system, resulting in faster cooking and greater volume while at the same time improving product quality. Eves and Weiner say that microwave booster ovens preheat the entire product simultaneously, including its center, so that less time and energy is required to achieve desired internal temperatures of the final cooked product.
Second, Lian Sawires of Gyrotron Technology Inc., Bristol, Pa., explains how heaters that incorporate high frequency microwave technology are designed to increase the speed and energy efficiency of coating, curing, drying and processing a range of materials. According to Sawires, specific applications that might benefit from using the high frequency microwave heating include adhesive processing, joining and glass processing.
Infrared thermometers are the focus of "Sensor Health Checks" by John Salemi of Ircon Inc., Niles, Ill. Salemi says the key to trusting infrared temperature measurement is proper installation, operation and maintenance of the device. Salemi cautions that despite the reliable accuracy of infrared thermometers, certain environmental factors must be accounted for to ensure accurate temperature-measuring performance. Fail to maintain such things as the power supply to the thermometer or the air supply to its air-purge unit and you may receive misleading temperature readings that can affect manufactured product quality and even risk catastrophic plant breakdown.
Finally, in "Effusivity for Drying," Dr. Yves Roy, Dr. Nancy Mathis and Adam Harris of Mathis Instruments Ltd., Fredericton, New Brunswick, along with their co-author, Normand Dubuc of Montreal-based Invensys, Auto-
mation, Pharmaceutical Solutions, explain online effusivity monitoring for drying applications. The authors assert that the main goals of using online monitoring are to improve manufacturing efficiency and product quality. Online monitoring provides a "process check" that occurs within the actual unit operation being performed. This allows you to modify a process in response to measured fluctuations, making it possible to achieve better product consistency.