VainEnd84 Posted March 12, 2017 Share Posted March 12, 2017 I've been tossing the idea for a no weld NARB, and wanted to get some feed back from the community about this idea. I'm going to attempt building it but I'm not certain if the idea will work. All input is welcome! My plan thus far is to use a standard 3/4" Frosty T burner but use a 3/4" x 3" reducer to afix the noslette to the mixing tube. I'm guessing that gas leaks my be an issue so I was thinking of brazing the reducer to the mixing tube. I was also thinking of using a noslette pattern similar to that used by stockmaker. I know that both stockmaker and Frosty have the mixing tube mounted perpendicular to the noslette array so I may use something like a 90degree street elbow between the reducer and the mixing tube, if the inline mounting doesn't work. Again any input is most welcome! Quote Link to comment Share on other sites More sharing options...
stockmaker Posted March 12, 2017 Share Posted March 12, 2017 I am going to give you my thoughts on this, and they are just thoughts, because I don't know for sure what will work and what will not. My bottom line on this, is it may work, but your chances of success are slim. I recall seeing someone selling a round 3" NARB head recently but it was not using the T Burner as a mixer. You are not going to find a lot of data on NARB design. My experiments with the NARB using the 3/4" T Burner (as with all burners) is that it is sensitive to the relationship between the size of the air plenum in the burner head and the size and number of the nozzle ports. This is where air/fuel mixing and backpressure association occur. In addition to this relationship, the entry into the nozzle head is important as well. Frosty's design uses a horizontal entry into the burner head with no diffuser, while the blown ribbon burners typically use a vertical entry into the head with a built in diffuser to spread the gasses. So the horizontal entry is in fact part of the diffusing system. Once you start messing with the size of the plenum, the shape of the plenum, the size/pattern of the burner ports , and the angle the gas enters the burner head, all bets are off, you are on your own. This week I abandoned my plans to use a 4" X 4" burner head, and am now simply going with exactly what Frosty has working as I am wanting to blacksmith and not do R&D on Propane burners. My 4"X4"X2.5" head would not settle down (kept backfiring) until I had the 17 ports reduced to just 13, the ports are each 5/16" in diameter. This was after I had cast two heads, and after testing with a wood filled test block which seemed to work fine. I have idea's as to why this happened, but like I said I really don't want to experiment with explosive gas's as I am doing too much guess work while not knowing what I am doing. So there you go, my thoughts on changing things, there is not much data that I have found to work with. Quote Link to comment Share on other sites More sharing options...
VainEnd84 Posted March 12, 2017 Author Share Posted March 12, 2017 Cheers for the input, that's pretty much what I expected, I just like tinkering sometimes and thought I'd try my hand at making this. I'll report back on my progress. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 17, 2017 Share Posted March 17, 2017 stockmaker, That was succinct and clear information on the subject; thank you for that. Quote Link to comment Share on other sites More sharing options...
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