[Stoves] More Hot Air - Flue Gas Testing

[John Davies]

MORE SENSORS FOUND :

I keep finding more sensors that might be more suitable for the simple 
combustion measuring device. Crispin is also seeking out solutions, and any 
alternative additions by other readers will be welcome. A larger list will 
allow a suitable combination at the lowest cost. A possible selection might 
be as follows.


OXYGEN
Figaro SK 25 -
 0 TO 30 %   - linear output  - Cross sensitivity to other gasses - 
Virtually no influence from CO2, CO, H2S, NOx, H2

CARBON MONOXIDE
Alphasense CO-CE with filter for stack gasses.
Rated at 10 000 ppm ( 1% ) -  linear output- Can measure up to 10%,  with 
0.6% deviation from linear output at 10 %
Cross Sensitivity to Hydrogen 60% , others negligable.

CARBON DIOXIDE
Alphasense CO2-D1 -  sutiable for combustion gasses.-
0.2 to 95% -  log output -
Cross sensitivity to other gasses, not given. ( maybe none ? )

NOTE
1 Testing my stove at SETAR shows H2 in the flue gas to be about 25 % of CO 
during the pyrolysis stage. This is not seen as a problem, as one wishes to 
lower the level of both gasses in the flue. This will cause the CO/CO2 ratio 
to be higher than actual, not a bad deviation.
2 using the above sensors will allow testing without having to dilute the 
flue gas.
3 the proposed flue gas measuring device is not aimed to be accurate, but an 
affordable tool for developing and tuning stoves.

Regards,
John Davies.

> John Davies wrote:
>> Points to ponder:
>>
>> <snip>Their O2 sensor 25% ( also with built in filter for flue gasses ) 
>> is sensitive to CO2 and over reads oxygen by as much as much as 10 % of 
>> CO2.
>> Could other sensors also be over reading with insufficient compensation 
>> built into the system?  The more I learn, the less I believe the claimed 
>> accuracies for combustion meters.<snip>