[Stoves] Re. Stoves] Oxygen Sensors for all combustion...

[andrew]

On Wednesday 07 May 2008 23:34, Alex and Christine English wrote:
> Has any body found anthing like this coming off the shelf that
> isn't priced for industry? They are using something like this in
> household boilers in Europe. We have spent about $500 for parts
> but with some help from some electronic wizards this could be made
> opensource and, perhaps, even more affordable.

Yes they're in some pellet boilers and I have worked on Kob woodchip 
boilers with them. I did note the Bosch part numbers somewhen but 
don't have them to hand. I take it they are wide band devices.

From looking at the voltage characteristics of simple car lamdbda 
sensors it seems feasible to interpret their output to derive a more 
linear and less switching effect by precise control of their 
temperature. I think this could be done with a 4 wire zirconium type 
if the flue gas being analysed is relatively cool because the heater 
wires have a direct resistance vs temperature relationship, hence by 
measuring VA through the heater wire you should be able to controll 
the temperature of the sensor accurately and given that interpret 
the ramp as it switches.


AJH