O2 Sensor

[Hypnotist56]

Hey guys -
I've been looking to find an oxygen sensor that fits certain criteria. I've been looking through oxygen sensors on Google and I can't really figure out what kinds of inexpensive oxygen sensors are available that aren't meant to go inside car exhausts. I would really appreciate it if someone here could help me in this regard, or at least post a link to a website that sells sensors which might peddle the kind of sensor I'm looking for! I'm looking to buy just a few now, but in the future, if all goes well, I might be ordering a few thousand.

Criteria:
Reasonable price (less than $150, excluding shipping, except if shipping costs more than $25)
Resistant to and unaffected by soot; sensor will be placed in a house hold chimney and should be well suited to EPA standards of soot in chimney smoke.
Sensor's readings should be accurate to within half a percent oxygen concentration in air, or more accurate
Sensor's operating temperature must be between 50 C and 500 C (i.e, a sensor that operates at 200 C to 300 C is just fine - we can adjust where we place the sensor in the chimney to allow for temperature adjustment near sensor position)
Oxygen sensor will have to deal with the moisture present in a house hold chimney (

Accuracy isn't as important as being rugged and resistant to extreme soot build up.

I'm also looking for a carbon monoxide sensor - this would operate in the same conditions as above, but accuracy obviously needs to be much more accurate - measuring on a ppm scale seems to be a good idea for our application.

Thanks so much!

 

[crerus75]

I believe the Bosch LSM-11 lambda sensor (0 258 104 002) was used in some chimney applications, in industrial and/or residential settings. It was also used in a lot of the early "wideband" lambda sensors for automotive use. It is not really a wideband sensor, but it has been used with wideband controllers in the past (MoTeC, ETAS, etc.). Here's a link to a spec sheet.

Note that the spec sheet is from the Bosch Australia site. The American Bosch site lists it as a Motorsport-series sensor (IE automotive use) only as far as I could find. I don't have a current price on the sensor or the controller you would need for it, as it is an older (obsolete?) design. I did use one in conjunction with an ETAS air fuel ratio meter many moons ago for tuning engine management systems and found it to be a reliable and fairly accurate sensor (more reliable than the very expensive ETAS controller, which went Tango Uniform on us during a dyno tuning session). Sorry I cannot be of more help, but this sensor was supplanted by newer and cheaper true wideband sensors, and as such I had limited exposure to it.

 

[mattsooty]

Hypnotist

It really depends on what you are trying to measure?

A standard Binary Sensor (Heated Exhaust Gas Oxygen Sensor) will tell you if you are Rich/Lean of stoich by the voltage it flows and if this is sufficient you could make something very cheaply.
Whereas a Wideband Universal HEGO will tell you %O2 of the feedgas but you will need some for of electronics to run the thing as they are a bit more complex. If you are only looking for 0% you will find it easier than if you are looking for Equivalence or Lambda Ratios, as I doubt your chimney stack is running a gasoline charge.

You may struggle finding one that can deal with the level of soot you are talking about though, as these sensors arent really designed for that sort of thing - though you may find the heating element burns it off I would recommend shrouding the sensor on the downstream 'face'.

Your maximum temp is well within spec but you may find inaccuracies at 50degC - unless you pay more £££

Hope that helps

MS