"Chirping" forge??

[P. McKinley]

I have a new dual burner, venturi gas forge that, after about 1 1/2 hrs of operation, began to intermittently "chirp".

Any explanations?

Thanks!

[Vinny203]

i get this on mine when using a 20lb tank and it starts to freeze up or to the ground i shake and continue.

[Clydetz]

Check for crickets. I'm sorry... I haven't had my 2nd cup of coffee yet.

[P. McKinley]

The other day I received an explanation from Stacy Apelt:

"A venturi burner draws the air in by the "Venturi Effect' caused by the gas jet. If the gas pressure gets too low, the venturi starts to collapse, and the resulting "chirping" is heard. It is caused by the flame moving back into the burner tube due to not enough gas/air flow to push it out into the chamber. The pressure needs to be turned up a bit at the regulator if chirping is heard. Do not run with a chirp, as the flash back and tube burning is not good for the burner.

The choke is how to adjust the air/gas mix, but there is a practical limit to how low a venturi will run. If a lower flame rate is needed, like for HT, building a blown burner is the way to go.....materfact, building a blown burner is the way to go anytime.

Ways to reduce the problem are;
Use a 100# tank to deliver a more even flow pressure and cut down on tank freeze up. The propane temperature lowers as it boils off to produce the gas we burn. After an hour of continuous boiling ,it gets to the freezing point and becomes slush in the tank. It will not deliver enough pressure to maintain the flame.

Adjust the choke to maintain a good flame. Make sure the chamber stays in the neutral to slightly reducing atmosphere state, or you will scale the heck out of everything you forge/heat.

Adjust the gas jet position. If the gas jet is movable. it may need to be moved in or out a tad.

Adjust the gas jet size. If the gas jet is a MIG tip type, changing it to a smaller size orifice will allow running at a lower pressure. The trade-off is that the burner won't get as hot at full blast as high as before.

Build a blown burner and make all the parameters adjustable. A gate valve in the air line and needle valve in the gas line will allow the burner to run from a candle flame to as big as the gas/air supply will allow. Virtually any forge can be retro-fitted to run as a blown forge."

[BennytheBlade]

Great info. Thanks for posting.

[melsdad]

O.K. can someone elaborate on a "blown burner" compared to the venturi?

[P. McKinley]

Melsdad - Here ya go. Again from Stacy Apelt:

"Venturi forge (AKA Atmospheric Forge) - draws in the air by the "Venturi principle" caused by the gas jet. The air supply is directly in relation to the amount of gas coming through the small orifice. There is basically no adjustment for these types beyond raising and lowering the gas pressure.

Blown forge - The air is supplied by a blower and the gas is supplied by a regulator and needle valve. They are mixed as they travel down the burner tube and burn as they enter the forge chamber. Since the air and gas can both be regulated to any amount desires, any flame size or forge atmosphere ( reducing, neutral, oxidizing) can be created easily. They are pretty much fool-proof, and can produce more heat than a small venturi can. Larger forges and those used for welding are almost always blown."

[melsdad]

Thanks Dacks