Fun with Heat: Lessons in Time and Temperature
While enjoying a perfectly delicious dinner with friends a few weeks ago, I asked the hostess how she prepared the potatoes -- specifically, how long she baked them. She seemed ready to detail every step in the food preparation process, but I forestalled her by assuring her I really only needed to know how long they were in the oven. “About 45 minutes,” came her reluctant and likely piqued response.
“Oh, that’s too bad,” I said, with regret. “They’re really good. But I can’t commit that kind of time to a vegetable.” Everyone at the table sat in stunned silence for a moment before bursting out in laughter.
I suspect some of my fellow diners thought I was making a joke -- and perhaps I was -- but it was founded in truth. Proper heating (cooking) times and temperatures are essential to achieve the desired outcome. In this case, that was a baked potato side dish, but that fact is equally true whether you’re curing a powder coating or drying inks in a printing application.
I was reminded of that dinner while reading “Streamlining Pasta Cooking and Cooling,” a case history detailing how Creative Foods, a specialty division of Brake Brothers that makes prepared frozen meals, sauces, soups and desserts for the U.K.’s foodservice and catering market, overcame challenges in the pasta-cooking process for its ready-to-eat meals. Creative Foods typically uses the long noodles such as fettuccine, linguine, tagliatelle and spaghetti in their meals. While these staples are a delicious part of the meals, the long pastas typically are difficult to process and tend to stick together, damaging the product quality and increasing waste. Creative Foods worked with Lycos Manufacturing, Columbus, Wis., to implement a rotary drum pasta cooking/cooling solution that provides water injection for agitation to keep the product in uniform suspension while moving through the unit.
The “Advantages of Passive Cooling and Laminar Airflow” for effective heat dissipation in power control systems are the subject of an article from Tim Wooley of Payne Engineering Co. Inc., Scott Depot, W.V. As Wooley says, laminar flow describes the condition of the boundary layer of air as it passes over the surface of the heat sink. Effective cooling employs this laminar flow, where the airflow is smooth, undisturbed and flows in constant contact with the surface of the heat sink material or coating, maximizing heat transfer.
Maximizing heat transfer in thermal fluid heating systems is the focus of an article by Scott Moore of Heatec Inc., Chattanooga, Tenn. “Maximizing Thermal Fluid Heater Efficiency” describes a way to increase a heater’s thermal efficiency and reduce fuel costs: install a heat exchanger in the heater’s exhaust stack. The heat exchanger recovers heat from the exhaust stack that would otherwise be lost into the atmosphere.
Also in this issue, Catherine Tetrick of Measurement Specialties Inc., Hampton, Va., offers “Thermistor Technology Review” with an overview of basic thermistor technology. She also provides some pointers that can help you decide if your application can benefit from using these versatile temperature sensors.
Finally, “Using Waste Heat for External Processes” from the DOE explains how the energy from gases exhausted from higher temperature processes can be recovered and used for lower temperature processes. Is your application a candidate? Turn to page 36 to find out.
Oh, and if you’re wondering if I really can’t commit 45 minutes to a vegetable? I took the recipe home with me.
Associate Publisher & Editor