Hefty Posted November 6, 2023 Share Posted November 6, 2023 Hi everyone, I have only worked with NA burners so far, some bought, some built, but I had an idea today that I'm curious about. This is NOT something I actually plan to build and test, I'm just wondering if it would work and I thought I'd put the idea here where more experienced people could politely tell me why it's a stoopid idea Could you make a blown burner by pointing a gas orifice at the intake of a centrifugal blower (IE an electric version of a traditional blacksmith's hand-cranked burner)? Problems I foresee: -You'd have to be able to eliminate the possibility of gas getting to the brushes of the motor and igniting. -You'd need to use a gas solenoid safety shut off valve in case of fan failure (but this is recommended for all blown burners, I guess) Positives if it would work: (if I have this right in my head) -more thorough mixing of fuel and air -less pipework needed Is it as simple as this, or am I missing something glaringly obvious to those who have experience with blown burners? I understand the basics of more common blown burner designs but just wondered if this variation (apart from the potential spark issue) could conceivably work. Cheers, Jono. Quote Link to comment Share on other sites More sharing options...
wirerabbit Posted November 6, 2023 Share Posted November 6, 2023 My initial thought is the positives as you have stated them do not out weigh the negatives. In addition to the spark ignition danger, you risk failing to entrain all the fuel gas into the forced air volume, which would come with a few more negatives. Fuel gas injection down stream of the forced air will mix well if designed correctly. I am also not convinced you would reduce any piping with your hypothetical design. Fun to speculate, but this might be a solution looking for a problem. Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 6, 2023 Share Posted November 6, 2023 That is exactly how I'd make a gun burner were I to do so. One of the guys in our club has a commercial gun that is built with the gas connection built into the blower. The blower speed control knob is right next to the needle valve on the blower itself. Pat usually uses it on his mid sized melter and then on forges if needed or at meetings. He mounts it directly to either firing through the refractory liner. It keeps itself cool with air flow and he removes it when he shuts it off. The worst drawback to wanting one of these particular burners being that Pat bought it decades ago and the company hasn't offered it in 30 years. There are others out there though. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Hefty Posted November 8, 2023 Author Share Posted November 8, 2023 Frosty, do you know if the club member's burner blower has any sort of protection from propane getting near the motor, or is this a non-issue? Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 8, 2023 Share Posted November 8, 2023 The propane can't flow unless the blower is running so it's all drawn into the flow and out. Any open vents between the impeller fan and motor have a strong flow of air from the back of the motor through and into the impeller fan. Propane would have to flow into a strong wind. It's also a brushless motor so there aren't any sparks. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Hefty Posted November 9, 2023 Author Share Posted November 9, 2023 Ah, that makes sense! Thanks! Quote Link to comment Share on other sites More sharing options...
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