Monday, August 24, 2009

Burn, baby burn!

I mentioned the burners yesterday so I thought I would show a picture of one of them. I bought two from Ward Burner Systems. They are a Ransome B4 Venturi burner with a BASO safety system and a Piggyback Venturi pilot. They are ported for natural gas and I intend to operate at up to 6 psi. I had to work with the gas company to make sure they would supply gas at this pressure. They were extremely helpful and actually ran me a dedicated line for the kiln at no cost to me. They hope to make their money back in the usage. I hope they do, too.

Yesterday, as promised I pretty much took the day off. I did unload the cone packs from the test firing of my electric Cress kiln and found as suspected that the controller is firing it too hot. I set it for cone 5 and when I pulled the packs cone 7 was down on all three packs that I put in. Good news is that they were even from the bottom of the kiln to the top. Now, I will have to see if I can get it calibrated.

My friend Ellen accused me of talking engineer speak yesterday. This is more potter speak, but a couple of terms that people might not know. Venturi burners use the release of gas at pressure to cause a vacuum to pull air into the burner to mix with the gas and then burn. The effect is named after Giovanni Battista Venturi (1746-1822)

Cones or more correctly, pyrometric cones are means of judging the temperature of and amount of heat that has been added to the pots. In the new computer controlled kilns, the internal program tries to match the way these physical cones work. Sometimes the computer gets off and you have to wack it a couple of times to get it back on track - just like me.

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