Bill Kielb Posted May 31, 2020 Report Share Posted May 31, 2020 1 hour ago, Sorcery said: Sorce Looks a bit low, light reduction? Link to comment Share on other sites More sharing options...
Sorcery Posted May 31, 2020 Report Share Posted May 31, 2020 Is that an updraft out? I'm likely trying to be "safe". I have been thinking about the difference between chimney lengths and how they might effect the sign, the size of an out flame is showing. It must be relative, yes? Sorce Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 31, 2020 Report Share Posted May 31, 2020 1 hour ago, Sorcery said: Is that an updraft out? I'm likely trying to be "safe". I have been thinking about the difference between chimney lengths and how they might effect the sign, the size of an out flame is showing. It must be relative, yes? Sorce Yes it is an updraft. Below is a pic of a Geil downdraft that is ventilated to a natural draft hood so right off the top of the kiln, height and size of Chimney was used to calculate the natural draft hood but in this case has little influence over the height of the flame. Very similar size flame actually to the updraft. The updraft is natural gas, the downdraft is propane so the downdraft is generally darker but both still go a nice boron / copper green late in the firing. Picture is a bit washed out by daylight but you get the idea. Also included the site port pic taken at the same time. Link to comment Share on other sites More sharing options...
Sorcery Posted May 31, 2020 Report Share Posted May 31, 2020 @Bill Kielb But how does the Height of the flame influence the reading on the Oxy probe in the respective kiln? Visible flame is irrelevant if the flame ends halfway up a thirty foot chimney, as the oxygen starved portion of the flame is well passed the ware chamber. You know what I mean? It is hard to explain. Sorce Link to comment Share on other sites More sharing options...
Mark C. Posted May 31, 2020 Report Share Posted May 31, 2020 I can field that question The more you reduce (either by damper in or closing air to burners or secondary air which is air around burners) the flame needs air ( what we call oxygen -really is a mix of gases) to burn and gets longer to find it-weather up chimney or out a spy plug. The oxygen meter records this as a larger number-push the damper in more =longer flame =more reduction -high the number on the oxy meter Its a direct deal flame gets longer meter gets higher numbers No flame (oxidizing atmosphere) meter is near zero on numbers Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 31, 2020 Report Share Posted May 31, 2020 37 minutes ago, Sorcery said: @Bill Kielb But how does the Height of the flame influence the reading on the Oxy probe in the respective kiln? Visible flame is irrelevant if the flame ends halfway up a thirty foot chimney, as the oxygen starved portion of the flame is well passed the ware chamber. You know what I mean? It is hard to explain. Sorce I do and I don’t The height of the flame is a general indication of the pressurization of the kiln and level of reduction. Color by way of how rich the mixture is and height the pressurization of the kiln. That along with a healthy site port jet indicates the kiln is filled with a reducing atmosphere and as a result secondary air (oxygen) is not being allowed in to oxidize the wares. In a brick kiln, site ports are very important to watch so one can know with some certainty their kiln is pressurized top to bottom with a reducing atmosphere. The upper site port will be the highest pressure and the lower port the least. As you open the damper slightly there will be a point where the lower port flame decreases to nothing, even thought he top port will still have a weak jet. The reduction atmosphere will decrease on the o2 probe and the flame above your damper will decrease in size and color. It is no longer overly rich and the kiln is less pressurized. Visible flame is never irrelevant it’s just another indicator of how effective you are at the moment. The site ports are key though and the lower port is very key if you want to keep unwanted air or oxygen from destroying your reduction on the pots it passes by.. So taken to the extreme though, many feet down the flue the mixture will cool, oxidize and no more flame to see. That part I get but it’s not pertinent to maintaining a good firing. A super tall chimney will outdraw the kiln bringing in more excess air So direct connect flues are more critical to proper sizing. Link to comment Share on other sites More sharing options...
Sorcery Posted May 31, 2020 Report Share Posted May 31, 2020 Yes yes! Sorry for being vague, I am coming from more of a high-rise building, plumbing and HVAC understanding of chimneys, that, coupled with my need to find every extreme of something in order to find my understanding, I realize I am talking about outlandish chimneys or what not, to illustrate a point, that may be confusing! I should say, I am thinking of that article on reduction firing which speaks of efficiency, and the flame tip being the "edge", if you will, of the "reduction zone". So my thought process says, if the flame tip is halfway up a chimney, you can have great reduction, without ever seeing a flame from it. Does that make sense? This... 3 hours ago, Bill Kielb said: firing. A super tall chimney will outdraw the kiln bringing in more Is more or less the "answer to my question", but, in the lovely world of internet communication, also served to be the point of..."unjumblestuffing"! Thanks for bearing with me through it! I have a pretty good understanding of reduction firing. I guess my biggest problem, is that in trying to be properly efficient, it pains me to use a process that is inefficient! I think that's why it's so intriguing to me, to dance that line, and get the most efficiency out of inefficiency as I can! Without getting as sappy as your hands at a fresh pine wood fire..... I gotta thank you fellers for the information, and for the not flipping out on me for trying to understand something in my odd fashion! Pressure, Lol! From the wife? The Sorceress is looking for rent, and I refuse to go work "for the man" again! That! Is what I'm afraid of! Hahaha! That's how important this is to me! Cheers! Sorce Link to comment Share on other sites More sharing options...
Bill Kielb Posted June 1, 2020 Report Share Posted June 1, 2020 3 hours ago, Sorcery said: Yes yes! Sorry for being vague, I am coming from more of a high-rise building, plumbing and HVAC understanding of chimneys, that, coupled with my need to find every extreme of something in order to find my understanding, I realize I am talking about outlandish chimneys or what not, to illustrate a point, that may be confusing! I should say, I am thinking of that article on reduction firing which speaks of efficiency, and the flame tip being the "edge", if you will, of the "reduction zone". So my thought process says, if the flame tip is halfway up a chimney, you can have great reduction, without ever seeing a flame from it. Does that make sense? This... Is more or less the "answer to my question", but, in the lovely world of internet communication, also served to be the point of..."unjumblestuffing"! Thanks for bearing with me through it! I have a pretty good understanding of reduction firing. I guess my biggest problem, is that in trying to be properly efficient, it pains me to use a process that is inefficient! I think that's why it's so intriguing to me, to dance that line, and get the most efficiency out of inefficiency as I can! Without getting as sappy as your hands at a fresh pine wood fire..... I gotta thank you fellers for the information, and for the not flipping out on me for trying to understand something in my odd fashion! Pressure, Lol! From the wife? The Sorceress is looking for rent, and I refuse to go work "for the man" again! That! Is what I'm afraid of! Hahaha! That's how important this is to me! Cheers! Sorce No worries. Since you have some high rise HVAC experience maybe think of it as a carbon monoxide filled kiln. The pressure is very small, just like the differential pressure in a high rise building. If you fail to keep a floor positively pressurized (slightly) then infiltration is often the result and increased outdoor air to condition along with potential moisture infiltration. And similarly just like a building with stack effect, the pressure builds from the top down which keeps the secondary air out or pushed low in the kiln so your stuff don’t oxidize. When I taught airflow in ductwork I would always ask that students think of it as a pressurized network we were simply poking the right size holes in. As far as the flame or edge of the flame, it’s not really pertinent. Folks have reduced in electric kilns by forcing CO in throughout the Firing cycle. Tough on elements though. One of my former students later in life supervised the pressure testing of the Braidwood reactor control building and ............... helped blow the roof off. Oops! He told me he finally understood that several inches of pressure although very small, amounts to lots of force over lots of square inches. He did comment that the event helped solidify the relationship between pressure and force though, so there is that. Link to comment Share on other sites More sharing options...
Sorcery Posted June 1, 2020 Report Share Posted June 1, 2020 @Bill Kielb thanks again sir! Bloody hell! Let me show you a picture of what my reduction flame looked like last go. It was a little bit shorter it seems. Though I believe it increased some over time, I don't think it got much bigger than the video flame. I got good reduction in that firing, but I only went to cone 6. Kept that reduction flame till the end, where I may have "cleaned" it out in the end with a little Oxidation. The video firing I am trying to figure out. It kept that video flame until about cone 8 or so, then to get the bottom 10 down I "pulled the damper to heat the bottom", as I read here, and I ended up dancing between small and "no" flame till I decided to shut it down. Damper only, I was trying to not add gas. I felt like it was "neutral", but I think it was enough to either reoxidize or never reduce. As it seemed a Very light reduction. I feel like "blaming" that period in which I was trying to get the low cones down, over that small size flame. I guess, along with any more of your thoughts, I'm wondering if there is a way to tell (by looking at wares) if it was reoxidized, or never reduced at all. Or if this concept even makes sense! Thanks Again for any insight! Sorce Link to comment Share on other sites More sharing options...
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