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Correlation Flowmeters by David W Spitzer and Walt Boyes

Ultrasonic flowmeters can be applied to fluids that are ultrasonically conductive. Correlation flowmeters are not ultrasonic flowmeters, however at least one design uses ultrasonic means to obtain its measurements. Correlation flowmeters measure fluid velocity by measuring parameters associated with flowing stream at various locations in the piping. To illustrate the general principle of operation, consider a flow stream that abruptly changes color from red to green. The color of the fluid could be sensed at two points that are one meter apart in the piping. If the second sensor detects the green fluid one second after the first sensor detects the green fluid, the velocity in the pipe could be calculated to be one meter per second. There are various flowmeter designs that utilize different measurements to determine the flow rate. Note that correlation flowmeters do not disturb the fluid flow, but rather passively or actively sense its characteristics.


Inspector Clou'fleau': An Application in Conflict Provokes an Investigation by David W Spitzer

Sometimes you have to do detective work so that you know what you have --- or suffer the consequences.  Such was the case when I was asked to audit a steam flow measurement system where the flowmeter was used to measure the flow of steam from a cogeneration plant comprised of a gas turbine and heat recovery steam generator.  I seem to recall that this flowmeter measured the flow of steam valued at US$10-20 million per year.  This particular measurement could be used to perform a steam system balance whereby the total amount of steam leaving the cogeneration plant could be compared with the sum of the billing flowmeters to monitor for measurement and/or operational problems.


Effect of Bubble in Impulse Tubing by David W Spitzer

What is the approximate flow measurement error associated with a differential pressure flowmeter for liquid service operating at a pressure of 4 bar where the differential pressure transmitter is calibrated for 100 inches of water column and the impulse tubing on the high side of the transmitter has a 10 inch vertical bubble of non-condensable gas?



In addition to over 40 years of experience as an instrument user, consultant and expert witness, David W Spitzer has written over 10 books and 500 articles about flow measurement, level measurement, instrumentation and process control. David teaches his flow measurement seminars in both English and Portuguese.


Spitzer and Boyes, LLC provides engineering, technical writing, training seminars, strategic marketing consulting and expert witness services worldwide.


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