Anyone who has attended the Industrial Heating Equipment Association's annual safety seminar has seen the slide presentation on catastrophic oven failures and heard the discussion of why they occurred. Like most calamitous events, the failures happened because a chain of events took place in the right -- or, given the consequences, wrong -- order to create an unsafe situation. Why did the chain develop unbroken? I blame it on good intentions.
You know what I mean -- you meant to review the updated standard, perform the required maintenance as scheduled, upgrade the controls. You were going to do it as soon as business slowed down, or when it picked up. But it didn't quite happen as planned. If good intentions are only followed up by bad execution, you can expect problems to follow.
Some specific examples are described in "Is It 1990 Yet?" by Energy Notes columnist Dick Bennett. He points out the industrial ovens and furnaces safety standard, NFPA 86, has called for annual safety valve inspections since 1995, and the emergency shutoff valve and leak test hardware requirements have been in the various versions of NFPA 86 since at least 1990. Yet many plants do not perform the required inspections and testing. Is yours one of them? Are your good intentions -- rather than good actions -- creating an unsafe environment?
You may also have good intentions about improving the efficiency of your heat processing equipment. In this issue, we have three articles that can help you execute your plan of action.
In "Improving Fan Operation in Curing Equipment," Mike Olson and Dave Polka of ABB Inc., Automation Technologies, Drives and Motors, New Berlin, Wis., explain how variable-frequency drives provide the adjustable motor speed that can boost productivity, reduce energy consumption and increase your bottom line in paint application and curing equipment.
As summer approaches, it may be time to upgrade or design your process cooling or industrial refrigeration system. In "Direct-Expansion Evaporator Coil Design," Bruce I. Nelson, P.E., Colmac Coil Manufacturing Inc., Colville, Wash., notes that many refrigeration systems incorporate direct-expansion evaporators. In most cases, failure of the direct-expansion coil to perform as specified is a result of a poor thermostatic-expansion valve or distributor operation.
Plasma spray coating is used in a range of finishing applications, including semiconductors, metals and architectural glass. Plasma spray coating is a process of thermally spraying one substance (usually in a powder form) onto another. Power control during coating is important to achieving the most uniform results. In "Improving Plasma Spray Coating Control," George A. Sites, Ametek HDR Power Systems, Columbus, Ohio, describes a power control system that may improve coating results.
Finally, in "Specifying Heat Transfer Fluid for Food Processing Appli- cations," Pete Frentzos of Radco Industries Inc., LaFox, Ill., explains the new NSF fluid categories. These regulations may make it easier for process engineers in food manufacturing to choose a heat transfer fluid.
Editor and Associate Publisher