I was wondering if anyone can answer a question for me.
I borrowed a flue gas analyser to check my oil boiler efficiency recently. It seems to be working just fine according to the analyser but there was one parameter 'smoke number' given on the boiler data sheet as 0-1 which the analyser didn't test for. Is there a conversion formula that you can use to get this figure. The analyser provided figures for flue gas temp, oxygen, carbon dioxide, carbon monoxide and boiler efficiency.
Thanks Jerry
I think smoke is particulate matter, and not directly related to the gas analysis.
Most analysers do not give a smoke reading. (A couple of expensive exceptions) but require the operator to use a Draeger type aspiration pump with a filter paper in the flow path of the flue products. A chemical test set such as a Brigon or a Fyrite contains the appropriate piece of kit. to use it you put the sample tube into the flue sample point and draw five full strokes of the pump through it to give the required volume pass. the filter paper is then removed and the sample "spot" on the paper compared\with standard colour samples designated on a scale known as Baccarach number. electronic samplers exist but suffer from smoke/soot deposits on the sampling optics
What figures did you get btw?
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jerry saying something like:
Don't take the chance of using the analyser without doing the smoke test first. Too high a smoke content in the flue could bugger up the sensor in the kit.
The idea is to reduce the smoke reading first, then use the analyser.
Have a look on ebay for 'smoke tester' and 'combustion analyser' and one or two smoke testers will pop up.
80quid a pop.In article , John writes
Hi
Do heating engineers normally do a smoke test when they test the flue gas?
The results I got were:
Ambient temp 25.1 deg C Flue gas temp: 159.2 deg C Oxygen: 4.6% Carbon monoxide: 10 ppm Carbon dioxide: 12.1% Poison index: .0001 Rat (whatever that is) Gross efficiency: 87.8% Net efficiency: 93.1% Carbon monoxide undiluted: 13 ppm (whatever that is)
The data sheet for the boiler only gives the following values: Smoke No 0-1, CO2 12%, Approx flue gas temp: 165 deg C
Jerry
It's probably the CO/CO2 ratio (it's about the right value). If so, figures above 0.004 (IIRC) tend to indicate the boiler isn't burning gas as well as it should, and figures above 0.008 would indicate a need for servicing. 0.0001 is a good value.
When dealing with oil boilers this is the first test you do! Drawing soot particles into an analyser "is a very bad thing" and results in rapid failure of the cell.
The only figures of note are those which the boiler makers give examples of. As you will see from your results the others are either simple indicators (useful ones though) or have very low levels as in the carbon monoxide reading (ppm = parts per million). CO is very low with pressure jet burners as incomplete/unsatisfactory combustion results in soot rather than CO hence the smoke reading test.
I seem to recall that poisons were traditionally tested by giving samples to rats - if the rat died it was poisonous!
As chemistry got more advanced they started measuring how strong a poison was - something twice as strong as required to kill a rat would be 2 Rat, something half as strong as required to kill a rat would be
0.5 Rat.0.0001 Rat sounds like a very low toxicity to me.
Oh, I didn't notice it's an oil boiler. The figures I gave are for gas. No ideal about oil, sorry.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jerry saying something like:
Looks like you got away with not doing a smoke test. The results are pretty good. For future reference though, you should ask to borrow the smoke tester as well as the analyser.
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