Checking Oxygen Levels in a Heat-Treatment Furnace

You have options:

1. Flame test : i dont no about environment inside furnace, if there r no inflammable gases, u can light a flame and take it inside furnace by some means. If flame stays there is oxygen, if flame extinguishes then there is no oxygen.

2. Use B2C cell from TELEDYNE or ANALYTICAL in some analyser to find O2 % or PPM

Hope it helps

Limbkar

Flame test is a bit basic for this application. The furnace is full of flamable gas but is way over the ignition temperature. The gas burns off at the ends where it combines with air.

The problem is that they sometimes get air leaks that affect the components being treated. Obviously large leaks would cause a bang if enough oxygen gets into bring the gas mixture below UEL. Small leaks simply cause rejects. I'm hoping to set up a basic meter readout to indicate to the operators that the oxygen level has risen.

Calibration is not important.

You need to put a sample point in the flue gas exhaust and use a standard oxygen analyser for the specific readings, it must be calibrated against a standard otherwise how would you know what level of oxygen you are dealing with, dependant on the size of furnace you are using you could put sample points at various stages along the length of the furnace to give you specific temperature, oxygen, and CO levels,

Thanks for the reply. I'm only really looking for a change in O2. This a electric furnace filled with endo gas. It's about 40' long and any air leaks cause problems. First thing they do when they have problems is start tearing it apart looking for leaks. By putting several sensors along the length, each conected to a panel meter I'm hoping that the operators will pick up any change in O2 levels before too many parts are ruined and also have some idea of the area to check. I suspect in many cases the problem is not air leaks but water vapour in the gas forming O2. In which case the sensors should indicate a general rise of O2 instead of in a specific area. From what John has said I should have no problems with my auto sensors. Now to put the idea into practice.

Steve

I've replied to your thread on the electronics forum.

But basically most gas flue measuring instruments work using a lambda sensor as they are very accurate, once operating temperature has been reached...

Yes, I have designed systems using them back in the late 70's and early 80's.

John.