[R Fraser]

My first firing was about 10 years ago, no fiber, one forced air burner, cone 10 in 4 hours. It was too fast, unlike the Olympic Torchbearer the top was 2 cones cooler. Over the years I added fiber, another burner and two collars. I added fiber to slow the cooling for better glaze colors. Adding the second burner at the top evens out the firing. The forced air burner are very efficient. I now fire in about 7 hours to cone 10 with about 9 gallons of propane.

Aloha, Ken
[/quote]

I love your burners! I was going to build power burners as I have a blower from by forge that I am not using but was not sure about the orifice size and pressure, to air flow rate ratios for optimal performance. New power burners are big $$, but as you demonstrate very easy on the wallet in cost of firing. I think I am burning at least 14 gallons of propane in a firing for this kiln. Did you make the burners yourself? You are probably using low pressure propane too?
Richard

[Rakuken]

R Fraser, on 09 February 2013 - 01:49 PM, said:

My first firing was about 10 years ago, no fiber, one forced air burner, cone 10 in 4 hours. It was too fast, unlike the Olympic Torchbearer the top was 2 cones cooler. Over the years I added fiber, another burner and two collars. I added fiber to slow the cooling for better glaze colors. Adding the second burner at the top evens out the firing. The forced air burner are very efficient. I now fire in about 7 hours to cone 10 with about 9 gallons of propane.

Aloha, Ken

I love your burners! I was going to build power burners as I have a blower from by forge that I am not using but was not sure about the orifice size and pressure, to air flow rate ratios for optimal performance. New power burners are big $$, but as you demonstrate very easy on the wallet in cost of firing. I think I am burning at least 14 gallons of propane in a firing for this kiln. Did you make the burners yourself? You are probably using low pressure propane too?
Richard
[/quote]

Here is a picture with a list of parts of my forced air burner. If you have any questions let me know.

Aloha, Ken

Attached File(s)

•  forced air burner (1024x765).jpg (176.56K)
  Number of downloads: 77

[R Fraser]

Rakuken, on 09 February 2013 - 10:28 PM, said:

R Fraser, on 09 February 2013 - 01:49 PM, said:

My first firing was about 10 years ago, no fiber, one forced air burner, cone 10 in 4 hours. It was too fast, unlike the Olympic Torchbearer the top was 2 cones cooler. Over the years I added fiber, another burner and two collars. I added fiber to slow the cooling for better glaze colors. Adding the second burner at the top evens out the firing. The forced air burner are very efficient. I now fire in about 7 hours to cone 10 with about 9 gallons of propane.

Aloha, Ken

I love your burners! I was going to build power burners as I have a blower from by forge that I am not using but was not sure about the orifice size and pressure, to air flow rate ratios for optimal performance. New power burners are big $$, but as you demonstrate very easy on the wallet in cost of firing. I think I am burning at least 14 gallons of propane in a firing for this kiln. Did you make the burners yourself? You are probably using low pressure propane too?
Richard

Here is a picture with a list of parts of my forced air burner. If you have any questions let me know.

Aloha, Ken
[/quote]

Love it! Guess who is going shopping this week end...
Thanks, Richard

[neilestrick]

You can get more efficiency out of you blower if you have it in line with the burner pipe. It's a little more work, but the air doesn't have to make a 90 degree turn to get out. Instead of a cross, join the 2" burner pipe to a floor flange using 2" coupling and close nipple. Ideally, you'll want a coupling that isn't cast, as it will be harder to drill through. The burner pipe should be at least 8" long for good air/gas mixing. Attach the blower to the floor flange. It's now a straight line for the air. The orifice will be a 1/4 pipe nipple that goes through the 2" coupling. Just drill a hole through the coupling (both sides/all the way through) and insert the nipple. Put a cap on one end outside the coupling, and make the necessary gas connections on the other end, outside the coupling. The orifice holes will be 3 holes drilled in the side of the nipple, aimed away from the blower. This is essentially the burners used on Alpine kilns, which run great.

Here's a burner system I built for a friend using this type of burner. Sorry for the poor photo quality.

 1controls.jpeg (55.83K)
Number of downloads: 67  16Burner.jpg (404.53K)
Number of downloads: 74

[R Fraser]

neilestrick, on 11 February 2013 - 05:27 PM, said:

You can get more efficiency out of you blower if you have it in line with the burner pipe. It's a little more work, but the air doesn't have to make a 90 degree turn to get out. Instead of a cross, join the 2" burner pipe to a floor flange using 2" coupling and close nipple. Ideally, you'll want a coupling that isn't cast, as it will be harder to drill through. The burner pipe should be at least 8" long for good air/gas mixing. Attach the blower to the floor flange. It's now a straight line for the air. The orifice will be a 1/4 pipe nipple that goes through the 2" coupling. Just drill a hole through the coupling (both sides/all the way through) and insert the nipple. Put a cap on one end outside the coupling, and make the necessary gas connections on the other end, outside the coupling. The orifice holes will be 3 holes drilled in the side of the nipple, aimed away from the blower. This is essentially the burners used on Alpine kilns, which run great.

Here's a burner system I built for a friend using this type of burner. Sorry for the poor photo quality.

1controls.jpeg 16Burner.jpg

Wow, that is a very cool set up. I think instead of re-building this kiln this summer perhaps I will build some power burners.
I do have a couple of questions: are you running natural gas or propane, if propane are you on 11in WC or high pressure. How did you determine the CuFt/minute for the blower to orifice match? Do you have an orifice chart? To do this my current build the high pressure pilots and Baso's were by far the most expensive part, but safety first. So I would need to base any power burner on the high pressure propane source if I want to include the pilots and Basos. I do have the Baso valve left over from the original burner ring from the Torchbearer and it is set up for 11in WC propane, and I know it still works, but it would be awkward to plumb it for 2 burners.
I discussed the merits of high vs. low pressure with Mr. Ward previously and the choice really only mandates the orifice diameter and may affect the turn down ratio in the end. But for the best efficiency getting the orifice right is probably pretty important.

Do you have a parts list for that build?

What kind of flame retention nozzle is that?

I like the inline design with the blower passing straight through. Did you say the orifice is directed away from the blower, as in following the airflow?

Sorry to bomb you with questions…

[neilestrick]

The kiln in the photos is running on propane. Don't know what pressure he has it set up at. My old kiln, which had the same burner design, ran on natural gas with 15"+ WC. I think Ward has an orifice chart on his web site. The orifice holes aim in the direction of the air flow. I put a notch on the outer cap of the orifice pipe to show which direction the holes were drilled so I could line them up properly. The 3 holes had the same total area as the necessary orifice size, so you'll have to do some math there. You can always drill them larger if it's not working properly. Each burner needs its own Baso valve, since the Baso feeds the pilot light. The system in the photos also has a high temp shutoff connected to solenoids on the gas lines. The more safety systems the better. Sorry, I don't have the parts list. It was several years ago that I built it. The flame retention nozzle is from Eclipse. There are others out there on the market now, even on eBay. My burners used a 2" pipe, 8 inches long. The old Alpine kilns used 6" pipes, but you get better air/gas mixing in the longer pipe. Alpine uses a 75cfm blower for their kilns up to 24 cu/ft (stacking space), and 148 cfm for the larger kilns. Ideally you'll want to hook up the blower to an appropriate rheostat to control the speed, so the blower size isn't critical, as long as it's not too small.

[JBaymore]

In very round numbers, you need 10 cubic feet of air (at SATP) to combust any fuel gas (or any other fuel in fact) supplying 1000 BTUs of heat value. That is for stoichiometric (perfect) combustion. If you want to have oxidation capabilities, then you need more than that amount (or you are then dependent on secondary air entrainment...which is not a great way to go due to potential poor in-chamber mixing issues). So for a 100,000 BTU per HOUR burner....you need to actually supply to the burner's mixing tube 100,000 / 1000 = 100 X 10 = 1000 cubic feet of air per HOUR.

Since most blowers are rated in cubic feet per MINUTE (CFM) you have to convert that above demand in the units used 1000 / 60 = 16.6 CFM. If you want a specific oxidation capability out of the burner.... say like 10% excess air... then you have to add that to the above number .10 x 16.6 = 1.66 CFM more air.

Now simply mounting a 16.6 CFM blower onto a home made pipe burner assembly will NOT end up getting that 16.6 CFM mixing into the gas supply....due to the Static Pressure created by all of the burner mixing tube pipes, any elbows, restrictions of the flame retention nozzle, and so on. So the blower selected will have to have MORE capacity than what the above number represents. The Static Pressure can be reasonably calculated... but the exact configuration of the burner would have to be known. Hence the kind of larger blower numbers Neil mentions on the A.D. Alpine kilns.

best,

.....................john

[R Fraser]

JBaymore, on 14 February 2013 - 09:45 PM, said:

In very round numbers, you need 10 cubic feet of air (at SATP) to combust any fuel gas (or any other fuel in fact) supplying 1000 BTUs of heat value. That is for stoichiometric (perfect) combustion. If you want to have oxidation capabilities, then you need more than that amount (or you are then dependent on secondary air entrainment...which is not a great way to go due to potential poor in-chamber mixing issues). So for a 100,000 BTU per HOUR burner....you need to actually supply to the burner's mixing tube 100,000 / 1000 = 100 X 10 = 1000 cubic feet of air per HOUR.

Since most blowers are rated in cubic feet per MINUTE (CFM) you have to convert that above demand in the units used 1000 / 60 = 16.6 CFM. If you want a specific oxidation capability out of the burner.... say like 10% excess air... then you have to add that to the above number .10 x 16.6 = 1.66 CFM more air.

Now simply mounting a 16.6 CFM blower onto a home made pipe burner assembly will NOT end up getting that 16.6 CFM mixing into the gas supply....due to the Static Pressure created by all of the burner mixing tube pipes, any elbows, restrictions of the flame retention nozzle, and so on. So the blower selected will have to have MORE capacity than what the above number represents. The Static Pressure can be reasonably calculated... but the exact configuration of the burner would have to be known. Hence the kind of larger blower numbers Neil mentions on the A.D. Alpine kilns.

best,

.....................john

Thanks for this. I was pretty sure that the math was done for this. This info is very helpfull.
Richard