Another FrankenBurner

3D printed plastic burner experiments (photo heavy)

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Just thought I would contribute to this talk of wasp waist burners , as I have gleamed some ideas from this site. 

Amal injectors use a simple copper cone for their taper long venturi, fairly easy to replicate either from sheet or pipe, or turn if you have access to a lathe. A morse taper reamer or pin reamer may even be close enough. If you go onto their site you will find a pdf with basic dimensions and pics. Approx taper of 1: 12. Their 3/4" has a venturi of approx 1/2", the 3/4 simply refers to the size of pipe thread. 

Currently working on a couple of all steel, water cooled narbs, powered by Amal injectors. Results so far are very promising, in terms of heat output and economy, no pop back and the ability to turn right down. Still prototyping at the moment, so time will tell.  

I had considered making my own version of their injector, as I have the necessary machine tools, but for the money just decided to buy them. It would be possible with a bit ingenuity to make a simpler copy with basic tools and pipe fittings. Their jets are very finely sized, so the 3D printer nozzles may be the way to go as a cheap alternative.

Cheers Billy

 

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So all this new discussion has given me some things to think about.  In all my experiments with wasp waisted burners, I kept the maximum output at 3/4" since I was trying to make a 3/4" burner.  This reduced the intake down to 1/2" depending on the length of the out-take funnel.  In looking at the pic from Frosty on the previous page, I realized that I was painting myself into a corner, and what I could to do was create a burner with a 3/4" intake, and allow the funnel to enlarge to 1".  Now here's the question....is this then a 1" burner, or a 3/4" burner?  Either way, the smaller wasps worked well, just had a much smaller flame (Due to restricted intake).  So I'm making this (printing up now) with the intake that I have that works best (rev3.4.1):

1731691160_Burner341wasp.thumb.JPG.5ea2ff24ce8af1e41a0ce65a455fc911.JPG

Then...All the discussion about the rabbit cage version by G-Son, I wondered what would happen if I added something like that to my 3.4.1 burner.  These are printing up as well (a 16 hour print...):

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Higher fins, same intake, top with hole to allow for choke, 3/4" output pipe.  I'm also printing one with a 3" wide intake so the fins are further from the center.  I'll let you know when I test it!

DanR

 

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32 minutes ago, D.Rotblatt said:

Now here's the question....is this then a 1" burner, or a 3/4" burner? 

Very excited to see those results!

About sizes… 1" burners and 3/4" burners have nothing to do with 1 or 3/4 inches, other than the tubing they're made of is graded by a system that once upon a time had that size, before it was changed to thinner wall thus increasing the internal diameter. I'd say scrap the incorrect grading and call it what it actually is. As it has (at least) two diameters of interest, it would make sense to call it a 0.75/1.00" burner, if those are the actual diameters of the waist and exit. You can even take one step further and grade them in metric, reducing the risk of confusion. Out with the old, in with the new. ;) 

In the end, the diameters don't really matter. The important thing is how much heat they put out, i.e. how big forge they can handle, if they are to be used in a forge. 

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I believe the consensus of opinion is that burner sizes are rated by the inside diameter of their mixing tubes, or the narrowest point of constriction in a wasp-waist (venturi) burner.

Because all the early home-made burner designs were built from pipe fittings, pipe sizing came to be used as burner size references. It probably is time to change that; good look trying :)

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Question for Frosty, do you happen to know what that final pipe size is in the forge you posted?  

Thanks for the information Billy.  Are your water cooled NARBs something you are keeping close to the vest or are you willing to entertain the curious?

4 hours ago, D.Rotblatt said:

is this then a 1" burner, or a 3/4" burner?

As Mikey stated, your mix tube is mostly 1 inch pipe.  I suspect this burner will need a larger jet, probably a bit larger.  

Full length tapered mix tubes can not be categorized into the same size categories.  The commercial burners I deal with are all rated in output capacity(btu/hr).  Not so easy to determine in your garage.  If you are using mig tips, you could compare to pipe burners which use the same tip at similar pressures.  

I am playing with similar.  The small tapered tube we cast is an adapter for half inch heads to a 3/4" mix tube.  I am able to go to the 045 tip in this burner.  I also have a straight 3/4" head(No tapered outlet from throat or spiral vanes) which induces similar air using the same jet.  I am now trying to figure out if there is much of a difference in performance(possibly in different applications), how so, and hopefully why.

I look forward to your results.

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6 hours ago, Mikey98118 said:

I believe the consensus of opinion is that burner sizes are rated by the inside diameter of their mixing tubes, or the narrowest point of constriction in a wasp-waist (venturi) burner.

Because all the early home-made burner designs were built from pipe fittings, pipe sizing came to be used as burner size references.

As many things so, the nomenclature works great until you step outside the box a little :unsure:.  I was amazed that just because of this I was limiting myself to a preset tube size...just following the herd.... Says something about the power that giving something a name has on our psyche.

I guess I was just trying to keep things modular.

3 hours ago, Another FrankenBurner said:

I am playing with similar.  The small tapered tube we cast is an adapter for half inch heads to a 3/4" mix tube.  I am able to go to the 045 tip in this burner. 

That's what I'm using on my new burners.  If you are getting that with a 1/2" opening and getting a neutral flame, I might have to give one a try...Hmmmm.....back to the Inventor for some designing! :D

7 hours ago, G-son said:

Very excited to see those results!

I'll post when I get them!  Thanks for your input!

DanR

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23 hours ago, D.Rotblatt said:

I was amazed that just because of this I was limiting myself to a preset tube size

Yes, but it's fun.  It's kind of the blacksmith burner way.  Trying to squeeze as much down the pipe as possible.  More btu's without staying within those confines is easy.  

We are reinventing the wheel back to the venturi burner but it isn't a fair fight.  Venturi burners are almost the only NA burners I see commercially.  I have been experimenting, trying to increase my understanding of the inner happenings.  I originally thought the outlet taper was about reduced downstream drag and vortex geometry but the more important thing happening is the increase in static pressure of the FAM at the delivery point.  

Now I am trying to determine how changing the inlet reducer shape, throat diameter, and outlet taper length changes the static pressure, what the limits are(and why), and what this does to the flame.  As Frosty stated, it's an endless journey.  

I took a handful of pictures of some of the commercial burners I have seen recently .  These are all low pressure, relatively large orifices, and low temperature application.  

This guy is one of 20 burners which were in a large HVAC unit.  

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This one is out of a large griddle top.  The orifice is behind the wall on the left size which feeds into the venturi under the cross bar.  

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Here is a shot of that venturi, after I cut the burner apart.

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This big cast guy is for a pizza oven.  IIRC he is 170,000 btu/hr.  He is a blown burner.IMG-1070.JPG.2e1efcb8e99035619d5dfa718dd87760.JPG

 

I thought this one was neat.  It is the only one that I have seen like it. It was on an old condemned HVAC.

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On the lower left you see the gas valve which is plumbed right into the blower housing.  The orifice discharges into the blower suction and the blower mixes the FAM as it is delivered.  

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