Control Engineering Instrumentation eNewsletter for June 2003
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Risks of low technology visualization
At one time or another, we've all used the simplest, lowest tech means of seeing into a process - sight glasses. But did you know that just three separate failures of sight glasses, two in chemical processing and one in a pharmaceutical plant, resulted in the deaths of 28 people, more than $67 million in damages, and $1.5 million in lost business?
I came across an eye-opening article titled 'Process Observations Sight Glasses No Longer Need to be the Weakest Link' on the L.J. Star website. The author, Andy Obertanec, provides a thorough explanation of what can go wrong with sight glasses, how to avoid sight glass failures, how to maintain sight glasses, and what to look for when selecting a sight glass.
How well do we understand wireless field instrumentation?
I recently considered installing wireless network technology in my office - that is until I read a couple of PC magazine articles that included benchmark reports. I was amazed how much slower wireless is to a hardwired network. Then I read an ARC Advisory Group report titled 'Use of Wireless Level Measurement is Increasing in Process Industries.'
The ARC report indicated power consumption and transmission range as the key things to consider. Perhaps it's because the ARC report focused on level that no mention was made about communication speed, but all this got me to wondering how well those implementing wireless instrumentation really understand and/or consider the pros and cons of wireless technology.
Sometime in the future, I'm planning to write an article about wireless field instrumentation, but before I do, I'd like to hear from the wireless field instrumentation pioneers (those with the arrows in their backs) and the experts.
In the world of wireless field instrumentation, tell me, what are the:
Lingering myths that have been overcome
Besides communication speed, I'm thinking one of the gotchas must be the new and unusual considerations that must be defined and evaluated in a wireless instrumentation deployment hazard analysis, but I'd like to hear what you think.
Educate me about this topic by sending an e-mail to firstname.lastname@example.org
For more on wireless, watch for the cover story in the July 2003 edition of Control Engineering .
Small video borescope inspects sensors and valves
Anytime you can see inside process piping and vessels without taking flanges apart, you have to get excited.
During a recent tradeshow, I stopped at the Everest VIT booth because they were showing live pictures inside a pipe using a 3.9 mm diameter video borescope. Having used borescopes to inspect engine and compressor cylinder walls in the past, I was amazed how clear the image was and how much maneuverability was available.
With only a few minutes of training I was able to maneuver the borescope into the opening where a pressure gauge had been removed, down the pipe and up through the valve seat. I could clearly see the rough, cinder-like surface where valve cavitation had occurred. Using the borescope's onboard camera, I snapped a digital picture for later download into a personal computer for further analysis.
Wood-handle screwdriver replacement
There are a bunch of readers who've never heard of placing the metal tip of a wood-handle screwdriver against a piece of rotating machinery and then placing your ear against the wooden handle to hear unusual noises originating from inside the machinery. (Try it, it works, and for years it was one of the ways a lot of mechanics did troubleshooting of rotating machinery.)
UE Systems isn't marketing its Ultraprobe 10000 as a wood-handle screwdriver replacement, but that's basically what it is.
The Ultraprobe 10000 is a multi-level digital ultrasonic condition analysis system consisting of a hand-held metered pistol ultrasonic sensing instrument with on-board sound recording, data logging, and single-digit frequency tuning.
Also included with the Ultraprobe 10000 is UE Spectralyzer FFT spectral analysis software providing inspectors with the ability to view and conduct sound wave analysis from recordings made of bearings, steam traps, and valves.
Do you know the answers?
''Learning is not attained by chance, it must be sought with ardor and attended to with diligence.''
- Abigail Adams
The correct answers are highlighted in red and shown immediately below each question.
1. Iron-constantan thermocouples are designated by the letter:
The answer to Question 1 is b - J
NOTE: An earlier edition of this newsletter listed an incorrect answer for Question #1. I apologize. The following letter designations are used to identify thermocouple types:
J = Iron/Constantan
K = Chromega/Alomega
T = Copper/Constantan
E = Chromega/Constantan
R = Platinum/Platinum 13% Rhodium
S = Platinum/Platinum 10% Rhodium
B = Platinum 6% Rhodium/Platinum30% Rhodium
G* = Tungsten/Tungsten 26% Rhenium
C* = Tungsten 5% Rhenium/Tungsten 26% Rhenium
D* = Tungsten 3% Rhenium/Tungsten 150 Rhenium
* Indicate these are not ANSI symbols.
2. The standard range for pneumatically transmitted signals is:
a. 3-15 psig
b. 5-20 psig
c. 1-10 psig
d. 4-20 psig
The answer to Question 2 is a - 3-15 psig
3. A process is called ___________ if heat input is required to produce a reaction.
The answer to Question 3 is a - Endothermic