When you run that thing on natural gas ONLY... I'm assuming your flame is not burning inside that pipe??? How are you controlling the location of that flame? With blower speed?
The first picture is taken down the burner and shows the baffle plate, it generates the velocity barrier. the velocity through the holes is higher then the 75'/ sec so as soon as it goes through the holes and the speed drops the flame comes back to the baffle plate but can't get through the Baffle plate.
Thanks for taking the time to write this up Yoda. What is a 5k ignition burner? If I may ask, what's behind your decision to just burn oil in your next furnace? N/G availability? It looks like your 2 NG tubes are just 1/8" copper dumping into the burner pipe but are coming in from from a single source. If it wouldn't be too much trouble Id love to see how the valves are set up. Pete
the 5k ignition burner will be much like a handheld propane torch mounted so that the flame is directed at the atomized oil cone. the reason for going to a waste oil fired burner is that the next furnace will be about double the size of this one. This one was based on cylinder heads but in the last year i have had enough orders that i have run my scrap source out of cylinder heads and had to take complete engines, i have had to tear them down and then the blocks are large enough that i can't close the lids on the furnace and puts me in a position that the furnace operates in a somewhat uncontrolled manor. The next furnace will be able to take a V6 in complete form and still close the lids. It will need to fire in the 750+ kbtuh range which is more than a residential gas supply can handle. It would also throw a flag to the powers that be. so the need to go to waste oil. I'll make a drawing of the burner block showing the gas passages tonight. Art B
That is quite an interesting arrangement. Thanks for posting all the details. Would it make sense to use a large diameter barrel, and fire a single burner in typical furnace fashion, ie: with a tuyere low on the furnace wall?, and have the metal drain out of an opening? I guess you really need the tilt-and-pour arrangement to get the metal out of the furnace. Seems like I have seen a dual-chamber melting design, with a melting burner on one chamber, and a holding burner on the other chamber, and perhaps the holding chamber used as a scoop-and-pour arrangement, with a feeder low in the wall between them. Both chambers looking sort of like typical furnaces, but liquid-tight. For an entire engine block, I guess the diameter would get pretty large for the melting chamber, but seems like a holding chamber would eliminate the need for tilt-and-pour.
most of my sales are still to the hobby market 45 lbs at a time, a low month is about 300 lbs with the highest month being 1200 about, 20% is above 800 per month, and about 20% below 300. last year was 5700lbs, 2016 was 6100lbs. I've looked at opening a site other then eBay but I'm afraid of not being able to meet the market, some of my customers are starting to order multiple boxes at time, if i can't get individual cylinder-heads i can't keep up if i have to tear the engines down, so the next furnace needs to be able to take the complete engine and i will need to be able to pull out crankshafts, etc. with the furnace firing, I pull camshafts out now once the aluminum breaks down on the heads, by getting the iron out before the aluminum is melted it keeps the FE level down. I think if the iron sets in the pool i would get higher Fe. I have started on the next furnace I'll take a couple pictures of where I'm at, I did the R&D on the burners with the duel fuel burner on my current furnace so that I could work the bugs out. one thing i found was that if the nozzle is to large, when you turn it down it starts pulsing. so i used a smaller nozzle and increased the oil feed pressure it allows the firing rate to go over the rating by about 350 to 400%, after that it stops atomizing and just starts squirting oil. This post rattled on a little sorry about that Art B
This is kinda playing into my potential indoor LPG build so I'm going to ask a related question. When running NG do you use flame back arrestor on the gas line feeding the burner...? I did on my propane feed to my brute. Not completely sure if it was necessary. I had it, so I plumbed it in.
Not sure about NG but in general from my research the only time a flame arrestor is necessary is when you have oxygen incorporated with the setup like a cutting torch, etc.
The only time a back flow preventor ( check Valve ) is needed is when the oxygen or air source has a higher delivered pressure then the fuel or NG. when using a venturi it generates a lower pressure area at the fuel injection point. Unless you are using a high pressure fan and a restricted outlet the possibility of the combustion air pressure being higher then the gas pressure is very slim. very few fans can generate 3.5"WC of static pressure. even a vacuum or leaf blower probably cant generate that level of pressure. Low pressure propane is regulated to 11.5" WC and NG at 7.5 at the meter. It is almost impossible to get that high a pressure from any blower that we have access to, the only air source that could deliver that kind of pressure would be a turbo charger in the exhaust or compressed air. The only way you can get an explosion in the gas line is a combustible mixture of fuel and air with air at a greater than 80% ratio pressure regulators by their very nature of operation are a check valve if the delivery pressure goes higher then the pressure setting on the regulator. Art b
Only natural gas burner I've built. Did it's job, on the cheap too. 18" 2"sch40 2" ball valve and a 120v bathroom exhaust fan. 35$ to put one together. Not sure how it would hold up in a furnace though.
