Heat treatment: How to detect a furnace leak?

Question

I am new to heat-treat and I just got hired in at a company that unfortunately does not (yet) have gas analyzers. Is there a way (besides after the fact) to detect a furnace leak say from the flame color?

Answer 1

The best way to detect it would be the old way; sniff! Most fuels now especially methane got odored and that's jut to be the first indicator, normally, you should NEVER smell any gas, if your systems are functioning well. If you want to follow the flame color rule, then you can't be so sure about it however, the flame color rule does apply in three cases rich combustion poor and adequate. I am sorry I can't provide you the color though, not too sure about that

Answer 2

I assume you are using an atmosphere furnace so you are pumping in a gas mixture at sufficient pressure and flow rate to prevent air from getting in. If the leak is in the pressure side of the plumbing, the soap solution trick should work. I am no expert on atmosphere furnaces but flame color should be an indication. I suggest checking the flame without a load so that any oils/ contaminants from the parts do not complicate the flame color.

I do know some about vacuum furnaces. The easiest way to check the integrity of a vacuum furnace is to measure the leak up rate (this is a good way to regularly monitor the "health" of the system). Pump the chamber down, blank it off, watch the pressure rise over 10 minutes. Measure the leak up rate again about an hour later. A virtual leak will slow down over time. A real leak will continue leaking at about the same rate until the chamber pressure gets up towards atmosphere. If you have a real leak but do not have a He leak detector, you may be able to find the leak by squirting methanol or acetone on the outside of the chamber. When a solvent is drawn into the chamber thru the leak, the pressure will go up much more quickly. You need to be careful because the solvents are flammable.

Good luck and be careful

Answer 3

More info is needed as to type of furnace and operation. The soap solution will only work to check for gas leaks from cold supply piping. I take it you are during heat treating in an inert atmosphere and are worried about air leaking in and causing oxide formation. If you operate under positive pressure for the inerting gas, air won't leak in. Monitoring vacuum level might work but it depends on how sensitive the detection method needs to be. Sampling hot gases can be tricky but some old methods used chemical reaction and color change to monitor exhaust gas. As I said, more info is needed.

Answer 4

if you're trying to look for a leak in a PIPE (i don't know what specific furnace) try first to cover it with soap by putting some soap in the sponge then cover the entire piping, if there is a bubble, then there's the leak

Answer 5

u should check the high pressur and low pressure , usually if it is less than normal figures there is a leak