Date: Mon Nov 24, 2008 4:38 am. By: Neon John
On Sun, 23 Nov 2008 12:34:53 -0600, funkbastler wrote:
On Sat, 22 Nov 2008 20:42:48 -0500, Neon John wrote:
On Fri, 21 Nov 2008 18:02:01 -0600, funkbastler <nobody@nowhere.somewhere.us wrote:
I'm not John, but....
http://energy.growmark.com/propane/Chapter9.html
Orifice charts are at the bottom of the page.
Bear in mind (if you don't already know) that the pressures are different for LP and NG, so adjust your regulator if you can, or compensate by adjusting the target orifice size if you can't.
this type of burner has absolutely nothing to do with what you cited. IT has neither a fixed orifice nor a pressure regulator. Suggest that you let us neonists discuss what we know, sit on the sidelines and learn.
No orifice? Inspirator? How's the fuel/air mixing accomplished?
Nope, neither.
Educate me, oh learned one.
Glad to.
the first thing you should understand is that neon fires, like most industrial glass working fires, use compressed gas AND air. In the case of neon, 2 psi is the standard air pressure and from 2 to 5 psi is the gas pressure. There is simply no need for an inspirator-type venturi device. And since the heat rate is varied over such a wide range, the gas valve serves as the "orifice".
Incidentally, it is common practice in the trade to refer to the things that make flames as "fires". Probably a tradition from before natural gas and compressed air were conveniently available. Nowadays "fires" and "burners" are used interchangeably. I like the old way and usually use "fire"
Second, I suggest looking at this page.
http://www.neon-john.com/Neon/Shop_equip/Ribbon/Ribbon.htm
This is the page on my homemade ribbon burner. Mine is both simpler and works better than commercially made burners. I have changed my fire around a bit since that photo was made. I added structure inside the Tee to form a venturi-like function and added a zero pressure regulator. Now I can vary the fire's width from a couple of inches to full bore with only a minor touch-up on the mixture.
All of my neon bending equipment is homemade because I could not afford commercial equipment when I decided to get into neon. I improved it in the process. Having a pedal control on the ribbon is a major change. That enables me to have an air conditioned shop because the high BTU input fire is only on when I'm actually bending.
You may also see some photos from my very early photo dump web site here:
http://bellsouthpwp.net/j/o/johngd/files/neon/
Some of these haven't made it to my new site yet.
Next, look at this page
http://www.voltarc.com/NeonFabrication.htm##Burners
Specifically
The economizer that cuts back flow after the mix has been set by needle valves. this conserves gas when not actually bending http://www.voltarc.com/NeonHyde12106.htm
Venturi mixer. In this device, the air goes in the bottom and the gas in the side. Inside the mixer is a venturi jet that the air blows through, creating a suction on the gas line. One sets the basic mixture with the gas valve and then varies the flame with the air valve. If a zero pressure regulator were used in the gas line then no further gas adjustment would be necessary to vary the flame size. The gas would follow the air. They're not so the air and gas must be adjusted.
http://www.voltarc.com/NeonHyde12464.htm
I don't use a venturi mixer, just a tee like in my ribbon burner. It requires twiddling with the gas more often but since I usually leave my cannon fire at the same setting, that doesn't matter. In my setup there is a S second tee that admits oxygen from a medical oxygen concentrator It works out to about 10% additional oxygen and REALLy makes a difference in how fast I can work. http://www.voltarc.com/NeonHyde12464.htm
Air needle valves. These have a gradual, non-linear (equal percentage) plug that results in very smooth and fine adjustment of the compressed air flow. http://www.voltarc.com/NeonHyde12136.12137.htm
Standard cannon burner head. It receives pre-mixed air/gas through a rear NPT fitting. The slits around the side serve as pilot lights to keep the main jets lit, the gas velocity of which being such that the flame would blow off otherwise. This is a general purpose splicing and bending head. http://www.voltarc.com/NeonHyde12468.htm
Knife-edged cannon head. Same as above but with a very narrow flame. This is normally used for splicing and some forms of gathering. Many shops don't use one but I do. It makes prettier splices than the general purpose cannon. The screens are the pilot lights as the slots are above http://www.voltarc.com/NeonHyde12469.htm
Canon fire with mixers. I don't like that design, as it is difficult to get both sides burning equally. I mount my mixer on the bench and run the mixed gas/air/oxygen through silicone rubber hose to a "Y" type Tee and thence to the burner heads. If the lengths after the Y are equal, no balancing needed. http://www.voltarc.com/NeonHyde12471.htm
Standard 16" ribbon fire. The metal at the right with the loop in it is a slide that blocks portions of the burner to set the amount of screen that gets gas flow. This unit sits on top of either a simple chamber that receives gas and air or the economizer. IT requires compressed air and lots of it, which is why I designed my burner to use a blower for the air. http://www.voltarc.com/NeonHyde12057.htm
These are the screens we've been discussing. Simply brass stock drilled with a bunch of holes. You'll note that they do not use pilot holes or slots. That makes the fire touchy to adjust. You'll notice from my burner page that I DO use pilot holes which makes the burner much easier to adjust. The leaded glass that we use requires an extremely lean fire, on the verge of blowing out, or else the glass turns black. The pilot holes make that a much easier condition to achieve.
24 inch fire. Works like the 16" one except that the slides work toward the center. Unless shops are doing very large work (Walmart channel letters, for example) most don't have this fire. It uses a LOT of gas, even when economized plus the partial flame is in the center where it gets in the way of heating already bent glass. when used, it's almost always used wide-open. http://www.voltarc.com/NeonHyde12103.htm
Standard cross-fire. Each tip makes a flame exactly like that of a propane torch. It pre-dated the cannon fire and many benders, myself included, like it better for smaller glass. The pencils are mounted on gimbals so that the intersection can be focused to a sharp point or spread out. One pencil can even be bent out for heating a small spot in preparation for blowing out the side of a glass tube to make a "tee". http://www.voltarc.com/NeonHyde12124.12123.htm
If you get on Youtube and look up the "how it's made" series for fluorescent lamps and for strobe lamps, you'll see much the same processes and fires, in an automated environment. NONE of these use atmospheric pressure fires with inducers or orifices.
If that's not enough education, let me know and we'll do some more.
John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Some people are like a Slinky .. not really good for anything but you still smile when you shove them down the stairs.