1oo2 voting for temperature transmitter

C

Thread Starter

christine

i am currently working in a project wherein we proposed to add new temperature transmitter to the existing tank to have a 1oo2 voting.

Current situation is we have an existing temperature transmitter installed in the tank. if I want to add new temperature transmitter to it, is there any other possible installation of the new sensor that I can use without drilling the existing tank for the additional flange connection?

or how about any proposed type of sensor that I can use as an alternative?
 
you might consider placement in valve-free connecting pipe,

but that depends on a number of factors such as your process, the fluids, the level of risk due to temperature excursion, a whole range of issues that require P&ID's, process material balance data, fluid data, equipment data, the criticality of the "interlock" etc.

If it is unavoidable, then you not only have to modify the tank, you also may be required to hydrotest it.

you already are aware that 1 of 2 does not constitute proper voting, unless you are describing an single vote over-ride function...
 
http://www.controleng.com/single-article/monitoring-critical-vessel-temperature/224a1b309e.html

In this article they propose IR thermal imaging as a non-contact temperature measuring method.

They are very convincing in the article and I think I believe them but in my experience doing temperature measurements indirectly or where thermo wells have to be used, leads to major control and reaction time problems due to increased thermal transfer rates. Now if you can live with that in your application I think a thermal imaging system can work for you if you use say three or four at different locations on your vessel and use the one already installed to compare and average a final output to your control system in whatever voting configuration you need but since the one will be different from the others, these readings are going to react very differently but like I said it all depends what you can live with and what you need.

If reaction time is critical I would go the same as “d” in saying to try and find a in or outlet pipe on the vessel for your installation rather than drilling into the vessel itself, unless your tank is not a certified pressure vessel. You did not supply this information so we cannot give accurate suggestions unless we know what type of vessel you are working on.
 
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