I have a few flame sensors at hand, like this.
I have extended the mounting of the actual ir sensor component, away from the pc board with a length of wire, to facilitate installation.
With this setup, I can easily & reliably detect a candle flame at 8" distance.
![Image](https://i.ebayimg.com/images/g/a9wAAOSwSoVf~7Qp/s-l1600.jpg)
I have an application for gas flame sensing, in a tight space, where there is a standing pilot flame and a main burner.
I want to sense the main burner flame, ignore the standing pilot and yet be far enough away from the flames that radiant heat doesn't damage the ir sensor itself.
This combo is proving impossible to satisfy in the small space of this burner. Within the combustion chamber, heat is excessive. Mounting the sensor outside the combustion area looking in through the access hole used for gas pipes and thermopile tubing etc, does not seem to get the sensor close enough to, or afford a sufficient view of the flame, even with max sensitivity dialled into the electronics.
Some kind of high temp diy (ie free / cheap) ir capable fibre optic solution appeals to me but is beyond my expertise. This way perhaps I could shorten the apparent distance between / improve the view of flame & sensor, through the access hole.
I note glass tubes filled with mineral oil are reputed to work as effective light pipes, but nothing like that comes easily to hand and I wonder about the oil flame combination and ir wavelengths for this method in general.
Any thoughts / suggestions / ideas come to mind?
Thanks,
Brian H.
Uxbridge Ont.