60th Anniversary: CE History from 60, 30, and 15 years ago on flowmeter calibration, analysis instruments’ computer capabilities, and managing risk
December 1954: Standpipes simplify flowmeter calibration
Instrument engineering does not stop with the design and installation of instrument systems. It must certify the accuracy of the system, and provide ways to demonstrate and recheck performance tolerances of the system’s components.
Not more than 10 years ago, about the only facilities available for recalibrating flowmeters were the hydraulics laboratories of the instrument manufacturers. With few exceptions, no companies outside the instrument industry had primary standards for calibrating meters.
Because of the large increase in the use of flowmeters, particularly by aircraft engine manufacturers, more efficient ways of handling the meter calibration problem had to be developed. In one engine plant, for example, 350 to 400 m must be checked every 30 days to an accuracy of plus or minus .5 percent to comply with standard military specifications. A much larger number of flowmeters must be checked regularly to less exacting tolerances.
December 1984: Analysis instruments reflect increasing computer capabilities
Process analyzers are becoming intelligent to the extent that they can do their online thing just as effectively as a pressure or temperature sensor. An analyzer can perform in a distributed batch composition loop or in a network of distributed plant safety stations. It can conserve energy by assessing combustion efficiency, then control fuel ratio to sweeten effluent. It can monitor potable or wastewater with instruments deployed in the latest networking mode. With such a prestigious roster of control capabilities, what is the future for microprocessor-based analytical controllers in distributed networking arrays?
In the discussion that follows, there is presumptive evidence that an intelligent analytical controller could become a source of crisis decision when operating as a knowledge-based system. Such a system whose memory is preloaded with "expert" input on the process at hand, would alter control strategy in response to analyzer-generated feedback command.
December 1999: Managing risk: Don’t fall flat
Broad grins on the faces of skydivers in free fall come from two things. First, the exhilaration of free falling through space just can’t be concealed; and second, skydivers are confident they have properly assessed and mitigated the risk before stepping out of an airplane. Careful inspection and preparation of equipment, hours of rigorous training, and reliable backup systems permit skydiving enthusiasts to make more than 3.25 million jumps in the U.S. in 1998 with less than 0.001% fatalities.
In process and manufacturing environments, risk assessment is too frequently reserved for formal hazard analysis and operability studies (HAZOP) conducted as part of a project. The reality is, hardly a day goes by when each of us is not faced with some form of risk assessment at home, in our travels, or at work.
Whether choosing to use a chair with rollers instead of a ladder, accelerating through a traffic light that’s about to turn red, or trying to do a heroic act to prevent a plant shutdown, each is a risk that we have chosen to take. In more situations than we care to count, it’s blind luck that keeps us out of harm’s way. Most of the time, it shouldn’t be like that! Most of the time there is time to proactively assess risk and develop appropriate precautions.
– 2014 edits by Chris Vavra, production editor, CFE Media, firstname.lastname@example.org
Review other Control Engineering 60th Anniversary articles below and other historical documents on the history page at www.controleng.com/history.