Thermowell Vortex Shedding

During a recent plant revamp, it was discovered that several thermowells should be replaced. These devices had been in service for years without issues, so it was an uphill battle to justify their replacement. The whole thing boiled down to vibration problems due to vortex shedding, and the potential for fatigue failure.     Continue reading

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Interactive graphs using R

During a recent presentation, I was asked how the interactive plots for several process models were generated. The details of the models can’t be discussed, but the graphing technique can. In the following “rpanel” example, the proprietary process equations were replaced with typical Lotka-Volterra (LV) equations.     Continue reading

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Flow Instrumentation Videos

Requests for explanations on the design and operation of certain flow instruments are very common. Except for custom-built devices, most instruments are now described in Youtube or Vimeo videos. Here are a few examples.   Continue reading

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All forecasts are wrong, but some generate fewer complaints

In the engineering business, it’s common to be asked for time series forecasts.   Production forecasts, man-hour forecasts, sales forecasts, the list is endless.   In those cases where the only available information is the time series itself, the “go to” forecasting method is commonly a “Black Box”, or some form of the ARIMA (autoregressive integrated moving average) technique.  These techniques do a good job of torturing usable patterns out of the original data, however they don’t provide insights into why the patterns exist.           Continue reading

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Control system migration using existing field wiring

At the beginning of any controls migration project is the debate over minimizing field wiring changes versus the advantages of all new/different cabling.   Since each project is different, there isn’t a “best way” for all projects.    This post provides examples of control system upgrades that re-use existing field wiring.   Continue reading

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U.S. Gasoline Supplied, Part 2 of 2

The following video is the 2012 version of one of a series of internal videos that were produced by Revision Group in 2006.       That series was used to estimate the effect of rising oil and gasoline prices on capital spending in the hydrocarbon processing business.     Continue reading

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U.S. Gasoline Supplied, Part 1 of 2

This is part 1 of a 2 part video series on gasoline supplied to the U.S. domestic market.    This video describes the transformation of the raw supply data into its seasonal component and long term trend.     Continue reading

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