HVAC burner question

[DavidF]

I have aquired a beckett burner in working order from a friend of mine and was wondering if this thing can reach iron melt temps by its self or do I need to make any modifications to it to get it to? Like a secondary blower or just gut the whole thing and use the pump and nozzle with a different blower?

[Jammer]

Do you know what the output BTU is? A friend of mine uses one the melt large amounts of ALuminum for ingots and sells them back to the scrap dealer. His is a large one, about a million BTU. Of course that's with the right nozzle, fuel and you hold your mouth just right. He's using waste oil so I'm sure he's not getting the Max.
The one I had was 200K BTU from a house furnace. I got tired of pushing it around and sold it. Now I need it.

[Harry]

I think you wont have any trouble melting iron with one of those burners. I bought one a couple years back and never did use it because about the same time I also bought a siphon nozzle and it worked so well I went that route.

With the burner like you have there are a few things on running them. First off you have to get it going and often times when they are pulled from a home there is something wrong with them. The next thing is filtering your oil, the nozzles used in these has a very small orifice and can clog easily though they do have a built in filter on the nozzle and the tips are cheap at around $5.

Once you get your fuel sorted and the burner in working condition its time for fire, and lots of it. This is the main reason why I decided to go the other direction. These units to my understanding are either off or balls out and I need more control. You have a very small range of adjustment using the pressure of the oil and of course the air needs to be adjusted to maintain environment along with this. Then you can also change out the nozzles for different ranges. Not sure how much this will allow for and the blower will need to be able to keep up with the largest nozzle used so an addition air supply may be needed.

The basic idea is the same with any atomizer, spray the oil out in a fine mist, mix with air and light. This works great for making fire but refining it to be able to control the fire is another story. With the siphon nozzle and fuel metering I dont rely on the siphon part, just use the nozzle to make the mist. A metering pump adjusts the flow from lead temperatures up over iron and a variable speed on the blower tunes the environment. These do require compressed air and I have added propane to mine as well just because it seems to give that extra oomph in the burn, faster burn means more heat lower in the furnace and it only takes a tiny amount to make a difference. I measured during one melt and used 1/2 lb an hour over the course of about 6 hrs.

With this setup I can set the temperature at say 1300* for aluminum and hold it there within a few tens of degrees which is very important for me since I mold and pour and sometimes can get busy away from the furnace, without a steady temperature you could easily gain 50* a minute so even just a few minutes of inattention will seriously overheat a melt. For guys that make their molds up ahead of time this probably isnt so important because they can tend the furnace with a more watchful eye and catch the melt when it is ready.

[DavidF]

Im not sure how many btu its rated for but it say it can take a nozzle from .5 gph to 3 gph I can probable figure out btus from that.
Ill be burning diesl with it not waste oil, just dont feel like having to filter and thin the wast oil to save a few bucks, maybe if i was doing alot of casting I would feel different but for now I dont mind spending a few bucks for fuel.
I wonder if I can get a thermocouple to turn this thing on and off to regulate the temp in the furnace? Ill have to look at the ones for kils and see how hot they can take it.
It will be some time before i set this thing up, im looking at building a much larger furnace than what i have now. I would like to be able to melt 50 - 75 lbs of iron Still have to do some more research first though. Not to mention save up some bucks for some refractory to line the fire breathing beast with.

[dallen]

if your using diesel fuel it has 138,000 btu's per gallon, if you don't mind what are you going to pour that will take 50 to 75 pounds of Cast Iron??

I belive a 1 gph in my burner that I throwed together and it melts iron, also the refractory in my furnace which is starting to look pretty ugly were the loose pieces around the burner opening are falling into the flame and melting. I plan to go to the next size down nozzle because when I am on oil and trying to run it low you can hear the flame fluttering like its getting fuel in drops instead of a constant spray.

so you will just have to play around with the burner till you figure out how to make it work for you. I don't really thing automatic temperature control is needed on a home furnace, on a kiln or heat treat oven yes, but I think like harry says if you learn your burner you should be able to lite it warm it up them adjust for the temp you want and leave it alone.

With my old burner I used to use propane and I would run 20 to 30 psi, with this new burner that I have put together I run the same blower and use 4 to 5 PSI of gas to melt about anything I put in the furnace.

[DavidF]

Dallen,
Im working on building a 2 cyl steam engine 2.5" bor 3" stroke, I doubt any one piece of the engine weighs more than 10 lbs but would hate to cast it one peice at a time. Plus later on down the road I may want to cast large aluminum parts like an automotive intake or maybe a cnc mill Not to mention being able to fit larger scraps and ingots into the crucible. I have a small furnace now made from a propane bottle lined with 3k refractory but it only has a 6" bore and I have been wanting to go biger since my first few casts. I am running a naturally asperated 3/4" reil type burner but have not quite got to iron melt temps with it yet, just made the iron kinda bubble up some and stick together but not melt.
For the next furnace I would like to have a 12" bore 12" deep and running on something other than propane.
I did test out the beckett burner today in the open air and it lit off just fine, burned off my eyebrows and made some serious fire.
Im listening to everyones input and thinking it through. I might try hooking up the pump and motor to a router speed controll and see if I can vary the fuel some and still get it to atomize, then run a separate blower that can also be adjusted. The one thing I dont like about this burner it that it would need a 4" bore tyre going into the furnace. Who knows, maybe ill just build a siphon burner like yours.

So you burnt up your refractory? what was it rated for, and what is the size of the bore on your furnace? Just curious so I can get a general idea of things so I know what direction to go in.

[Harry]

I see it a little differently David concerning the Beckett sty burners. I am of course speaking from just what I have read on them and not actual experience but everything I have seen is they are either full on or off which means a run away train as far as temperature goes. A PID with a themostat would be great if you could get something that would handle the heat. You could then set up a range for on and off and the burner would hold the temperature desired.

Now this doesnt apply to siphon nozzles because you feed the nozzle the amount of fuel you want and can adjust this over a wide range. A 1 gph nozzle is rated at that for the 3" or so of lift of a certain viscosity fuel. As soon as you elevate the tank or add a pump you change the rate of the nozzle. I have used the 0.20 gph nozzle at a flow rate of over 1 gph simply by pumping the fuel through. I use a peristaltic pump on a dc controller that will vary the speed of my pump motor from somewhere around 10 to 500 RPM. Another speed control for the blower air and tuning is easy at any level of fuel use.

While I really like the siphon burner for its component simplicity, any piece can be easily replaced and back in service in minutes, I have to think a beckett style burner set up with a temperature sensor would function pretty damn sweet. Honestly I can see myself eventually moving to electric for aluminum casting just for ease and complete lack of emissions, even a straight up propane system would be viable as long as it had off on control.

[dallen]

the wall in my big furnace is made with 2700 degree insulating refractory, I have enough 3000 to reline the wall. but i am waiting till I get this burner figured out. my problem isn't that I can't melt it, its that I don't get to do enough casting to really figure out what the burner is doing.
heres a link if you want to see what I throwed together.

http://s1222.photobucket.com/albums/dd4 ... %20burner/

My furnace is built out of a what is called a short 60 water tank, I can't remember what the dimensions are. I can put an A20 crucible in it and still have plenty of room for tongs and burner flame. if your planing on doing large melts I would advise that you make your furnace at least 18 inches deep, and A20 is real close to 12 inches tall and with a block under it your going to need 4 inches for that. and them a little extra at the top. so I would go 12 X 18 I think mines pretty close to that.
Heres a link to a video of an iron pour that I did back in October,

http://www.youtube.com/watch?v=MN-3haEe ... er&list=UL

if you listen you will here that studdering I was talking about that I think is caused by the 1 gph nozzle. you will also probably notice the the inside of the furnace is almost white from heat, and that there is no flame coming out the top. during this melt I was also running propane into the burner at about 3 to 4 PSI, I don't really need it but it makes the burner burn so much hotter. I believe Harry is also running gas on startup but cuts it off so that he can control the temp for melting Alumium.

[Harry]

David, I get a pulsing with my burner also which I believe is the nozzle starving itself then refilling. Dont think this is any kind of a problem and never worried about it as long as it balances out to the atmosphere you want and the heat you want. I know I can turn up the pump and the pulsing will go away until I turn up the compressed air.

On the propane, last casting I was doing I was leaving the propane on but I dont think I was getting more than 1 or 2 PSI. It does make the oil burn quicker and just makes the whole thing seem like it is running more like it should along with being cleaner and as I continue to close in my foundry area cleaner is better.

Last couple of weeks I have been working on the shop and have not done any casting. Need to get back to it soon because I have a ever growing list of things needing done along with getting flask parts done, sick and tired of using worn out wood flasks and refuse to make replacements because that will force me to get the aluminum ones done.

[DavidF]

Harry,
let me start out by saying im the kind of guy that if you set something thats broken in front of me, and told me not to touch it or you would cut my arms off, I would still have to try and and fix it. Its a curse. Ok onward and forward, What if the burner had an adjustable dwell time? On X and off X that was variable? There would be some surge in temp but the radient heat of the metal and refractory lining would balance out to a certain temp that could be maintained....???? Jeez see what you did to me, poof simplisity right out the window LOL