how do conductivity meters measure at winter conditions ?
how do conductivity meters measure at winter conditions ?
(OP)
Hello all,
I have been working on a system which requires (electrical) conductivity measurement of organic metarial in an aqueous stream. The aim is to prevent organic material to end up in drain lines. This is done by shutting off the valve on the pipeline when the conductivity meter shows very low values (organic material has very low conductivity with respect to water).
The conductivity is related with temperature. My question is how do condutivity meters work when the temperatures are below 0 degrees celcius ? Do they need insulation around ? Another thing is how do they correct the conductivity measurement when the temperature is changing during the day ?
I have been working on a system which requires (electrical) conductivity measurement of organic metarial in an aqueous stream. The aim is to prevent organic material to end up in drain lines. This is done by shutting off the valve on the pipeline when the conductivity meter shows very low values (organic material has very low conductivity with respect to water).
The conductivity is related with temperature. My question is how do condutivity meters work when the temperatures are below 0 degrees celcius ? Do they need insulation around ? Another thing is how do they correct the conductivity measurement when the temperature is changing during the day ?





RE: how do conductivity meters measure at winter conditions ?
Dejan IVANOVIC
Process Engineer, MSChE
RE: how do conductivity meters measure at winter conditions ?
RE: how do conductivity meters measure at winter conditions ?
RE: how do conductivity meters measure at winter conditions ?
Conductivity is the ability of a solution to pass an electric current. This depends on a number of factors
including concentration, mobility of the ions, valence of the ions and temperature. As the temperature of a
solution increases, the mobility of the ions in the solution also increases and consequently this will lead
to an increase in its conductivity. Therefore it is mandatory to always associate conductivity
measurements with a reference temperature, usually 20ºC or 25ºC.
Most conductivity cells and meters have automatic temperature compensation (ATC). During ATC, the instrument applies a temperature coefficient of variation to the measured conductivity and reports what the conductivity would be at the reference temperature, as illustrated in Figure 1. This is known as linear temperature compensation and can give a good approximation to the true conductivity when the temperature of the measured solution is close to the reference temperature.
Since your purpose is not to obtain a precise conductivity meter, the temperature effect is somewhat irrelevant. You are looking for a spike in the reading to indicate organics/
RE: how do conductivity meters measure at winter conditions ?
Is this the right meter to measure biological oxygen demand and / or other organics in waste effluent streams ?
RE: how do conductivity meters measure at winter conditions ?
I see now how the temperature is corrected.
It is true that I am interested in spikes in the conductivity measurement to detect organics.
The issue I am thinking of is what will happen if there is low measurement or spike due to lowered temperatures ?
Then there is a risk to close the valve although no organics present.
Maybe as you mentioned this a question to vendor.
RE: how do conductivity meters measure at winter conditions ?
If the analysis shows that you are entering a zone in which reliability of the system is affected/reduced significantly, you will probably need to look for using different principle of contamination measurement. Discuss with the supplier.
Dejan IVANOVIC
Process Engineer, MSChE
RE: how do conductivity meters measure at winter conditions ?
RE: how do conductivity meters measure at winter conditions ?
RE: how do conductivity meters measure at winter conditions ?
Section 8.17 is dedicated to conductivity meters. The information extracted at ftp://ftp.unicauca.edu.co/Facultades/FIET/DEIC/Mat... shows overview of oil-in-water analyzer principles.
Dejan IVANOVIC
Process Engineer, MSChE
RE: how do conductivity meters measure at winter conditions ?
These conductivity probes in this attachment ( which have gained some notoriety in the business I come from) are for detecting an oil to water interface when there are two discrete phases to work with. These are still being used in phase separation operations ( by detecting interface level ) in the hydrocarbon industry.
Typical oil - in water analysers for effluent water stream monitoring are of the UV or IR type for measuring trace dispersed oil content in a continous water phase, which is what I believe is required in this application.
Even these UV and IR sensors dont give you the total organics content; vaguely recall some of these measure only dissolved oil in water, while others measure only free oil in water.
RE: how do conductivity meters measure at winter conditions ?
RE: how do conductivity meters measure at winter conditions ?
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