Kwiky burner with a twist

And it’s been four hours since it was lit. This is a cold start with just the combustible air and diesel. I guess this makes it a drip burner as well.

 

Nice to see it light off on diesel alone. That will be convenient.

One thing I am wondering about is the velocity of the fuel/air mix as it enters the furnace. Since your burn tube is small and the cumbustion air is somewhat pressurized compared to, say, a leaf blower, I am wondering if the flame front will also be pushed well into the furnace like an "anti-Ursutz" , if you will, burner setup. That may pushed flamefront might not be desirable. I am thinking, based on my recent testing of low pressure combustion air and raised plinth, if there might be some advantage to trying to slow the airspeed of the air/fuel mix as it enters the furnace so combustion has time to progress nearer the entrance to the furnace and therefore has progressed well by the time the air/fuel mix encounters the crucible. How might that slowing be accomplished? I am thinking a 30 degree included angle (15 degrees each side) or so flare on the end of the burn tube and perhaps 3 or 4 inches in length would force the stream to expand in cross section and therefore necessarily slow down. So atomization would occur outside the furnace, the flare would occur beginning just outside the furnace and continue through the insulated furnace wall and end at or a quarter inch the inside furnace wall. That way actual combustion might start shortly after entering the furnace and would be moving slower so it could progress well prior to encountering the crucible.

I will be the first to admit that this post is composed of idle musings that may or may not reflect reality. But, as food for thought, I decided to toss them out there.

You have done nice work on the burner to date. Way to go.

Denis

 

I appreciate it Dennis. Thanks.

I also agree with you. You did not get to see what I saw well I was testing the brass Venturi tip.

I set it at a point where it atomized water Best during my testing. This did two things. I could hear the turbine spinning a little more freely which means I was adding back pressure, and I was not getting the full potential of the CFM. The second thing I noticed is a higher pitch whistle coming from the Venturi. It was easy to play with when it was water and even easier to play with without water.

When the Venturi was shifted closer to the tip there was more of a spattering then Atomizing. The air pressure was greatly reduced as well. I’ve been thinking about this since the last video I posted up here. I’ve been trying to figure out how to adjust that Venturi with a mechanism on the outside. And/or When I put the tube that enters through the side of the furnace (I forget the fancy name) maybe have a 1/8” clearance so it naturally syphons atmospheric air with a threaded damper.

The last two burns I did I was burning less than .4L in five minutes. That peanut butter jar completely full wise .8L

In comparison to the water test, with the diesel I only had 1 foot of syphon head pressure. It would only squirt out of the nozzle with the head pressure 3” linear stream . Where with water at 18 to 20“ I was getting almost 5” linear stream. There is a little bit of pressure and viscosity playing it’s toll here. For the diesel burn I also cut the Feedline to half length, from 10 feet to 5 feet.

In my opinion there are so many variables going on...until I figure out the height for a dispensing fuel and even introduce oil with its viscosity, I will have no hard conclusion.

Edit; during that last video I only got to about 3/4 of the fuel ball valve open with the combustible air fully open. My wife was filming and she was giving me this cutthroat signal to shut it down. Once she did that I slammed the ball valve on the fuel closed. The rest is in the video.

 

Looking really good so far. Impressive to see that vac draw the fuel without a compressor. I think your burner is good to go at this point. Time to turn your attention to the furnace. Give us some dimensions you are considering.. You get a crucible yet?

Why'd the wife say kill it? She getting scared? These are really safe burners as you have seen. Propane gives me chills.

 

The wife does not like answering questionable questions. She also said it was getting hot and she was nervous. Some neighbours were overseeing. She doesn’t like being the redneck just the rednecks wife. Typical insurance broker… Avoid accountability.

As for crucible, #8 to #12 for my portable mini foundry. Depending on the type of brick I get (I’m hoping to use the same torch and) and second stationary furnace maybe go bigger with a two-man lift.

 

Lol.... Sounds like to me you need about a 12-14" inner furnace diameter, say about a depth of around 16" with a 4inch exhaust hole.. Is that about what you are thinking??

 

Close.. ID 12” x14” but the exhaust hole. I was thinking starting 3-3 1/4” and get bigger if needed. I figure I’ll start with 8Kg Silicon Carbide Graphite like...

 

I wouldn't go smaller than 4" on the exhaust. You can always cast a filler ring out of Mizzou and make it smaller. If your lid is cast, you dont want to bust that stuff out. it sucks cutting holes bigger. You can have the most powerful burner, but if you can get the burnt fuel out, it will just choke itself out. Mine is 3inches and I wish it was bigger. This is not a place to insert short D* jokes to those of you clowns. Maybe its time for a poll around here for exhaust hole size in use..

Yeah 14" deep is plenty.. figure a 3inch plinth.

 

I would also sugesst a 4" vent. OMM, you mentioned in your last post hoping to get some additional combustion air by leaving some space in the tuyere around burn tube. The more your furnace is pressurized the less that will work. And access for skimming and adding more metal is desirable. A 4 inch hole is the minimum for that I think.

I would be thinking 4 or 5 inch plinth, again to allow combustion to proceed well prior to contact with your crucible. Your interior dimensions will accommodate that height. I think the concensus in the recent discussions on furnace design has been to err on the larger rather than smaller interior dimensions, again to improve heat/combustion. (Put another way, I have yet to read someone wish their furnace interior were smaller.)

Denis

 

Denis said that better than I did.. Kinda like any engine.. The more fuel you can get it in, burned, and quickly outta there making room for the new incoming unburnt fuel. Or if you're a car guy.... "No replacement for displacement"
Savvy?

 

Regarding this idea of the fuel/air stream being cold: on my first furnace my burner tube pointed at a sort of tangent to the crucible—-not at all good I now know. But I remember being VERY puzzled to see flame impinging on the crucible but at the same time noting that the point of impingement was black where the rest of the crucible was various shades of red. And, yes, the fuel/air stream was burning by the time it impinged. But, in retrospect,I now know that it was just starting to burn there and so was relatively cold. The flame that had already made a circuit around the inside of the furnace was far hotter and was heating the remainder of the crucible pretty well, but could not keep up with the cooling effect of the stream right a the point of impingement. There has to be a lesson there....

Denis

 

Matt-

I started watching some of your videos last night.
Very interesting stuff you have.

A few comments from the peanut gallery that you may consider:

1. When I get things that melt too close to the hot end of the burner tube, they tend to melt from the inevitable blowby around the burner tube at the tuyere (valves, gauges, etc).
2. The correct term would be "combustion" air, not "combustible air". Air will not combust, but the oxygen in it will enable the oxygen/fuel combustion process.
3. The crucible seems to get hotter if it is elevated to within 1 or 2 inches of the lid.
4. Generally I have seen "clay graphite" or "silicon carbide", but it has been an either-or situation.
The Morgan clay-graphite crucibles are ferrous-metal rated (as well as non-ferrrous metal rated), and they have a higher temperature rating than the Morgan silicon carbide crucibles which are non-ferrous-metal rated only.
For an oil burner, I would use a Morgan clay-graphite "Salamander-Super", not to be confused with the "Salamander" label that Morgan uses on some of their other crucibles.

I have tried a lid opening that was 8" diameter, and while I was able to melt iron that way, it seemed to be slower and less efficient than a smaller opening.
I forget how large my current lid opening is, but I think it is about 4" diameter, and as others have mentioned, that allows skimming through the opening, and seems to work well.
As others have said, I would not use a lid opening smaller than 4" diameter.

I am following along with your foundry adventures.
Good luck.

Edit:
Crucibles are sized by number, and you can quickly figure out the maximum nominal capacity of the crucible in pounds by using the crucible number, ie: a #10 crucible will hold about 10 pounds of aluminum, or roughly 3 times that much in brass/bronze/iron.
A #20 crucible will hold about 20 lbs of aluminum, etc.

If you mention a crucible, you should mention the crucible number so we know what size you are talking about.

Here is a Morgan "A" shape crucible chart (inches on the left, metric in blue).
The bilge shape crucibles hold a little more metal for a given size, but they are difficult to source, and so most people use the "A" shape.

I have seen some supposedly "iron-rated" non-Morgan crucibles used by others that folded up like a wet waffle under oil-burner temperatures, so I highly recommend going with a big name brand like a Morgan salamander super.



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Super helpful Pat.. Good post buddy!

 

Well I’m back at it again. This torch isn’t done until I’m happy.

This is what I’m planning on doing to make the nozzle Venturi adjustable.

 

I had the day off today so I decided to stop by the crematorium, as I’m still waiting for a call on the brick.

I got a (2 hour) full tour. It was really neat. He explained each furnace was 2 million BTU with a 1 million BTU afterburner. I got to see old stainless steel and titanium screws, joints...

Originally, I believe he told me they had 5 different types of brick.

He clarified it was only two different types of bricks. I didn’t measure the brick but they all look to be 2×4×9.

The floor and walls only showed the long rectangular side (similar to house bricks) with almost zero mortar in between.
He said there is three courses of stacked brick and the 1st to 2nd course 1” has white insulating blanket and repeats the 2nd to 3rd course. The third course to stainless steel outer wall, had this 1 inch thick dense shield. The floor and first 6 courses of brick were the very heavy dense brick. The next 16 courses were the very light density brick. The ceiling of the furnace was the light density brick set in an arch. He also explained he could get over 600Days of of high temperature burns because he does not thermal shock the brick.

He told me, these furnaces and type of brick, do not like heat shock. He says he keeps them burning on Sunday to maintain 800°F. He uses NG with a 1 1/2” pipe feeding each furnace.

He also told me about his other crematorium has 6 million BTUs for pets, something about the amount of fur and air toxins.

I also got to see what he called high temperature glazing. He said the denser brick handles it better. He gave me a good suggestion to put one of the denser bricks in the direct shot of the burner and make it easy to replace.

I am also halfway through building my second Kwiki. This is the one I’m going to attempt to have only a half inch burn tube. I also found myself a few small DC pumps. They have a maximum 40 gallons per hour and 7 psi. The pump states it has a 70 µm filter in it. The only problem is it is 24 V DC.

 

Crematorium? Yeah, I think I'd have to pass on that tour. Wonder if that creepy bastard gets to pocket the gold he finds when sweeping up.... Ahem.. ?
That's a job I'd want no part of!

Hey Matt... 24vt is no big issue... Look on fleabay and get a cheapy chinese power supply.
https://www.ebay.com/itm/30V-5A-DC-...=152857635607ae00308f9ac94b4e82ef186af7f9ab52

 

Jason, the guy was an absolute gentleman very professional with a professional tradesman to tradesman attitude. It became a small world and very cordial when he knew my profession and found out that I’ve apprenticed One of his best friends son. It’s a small world.

 

It's still a creepy job... Someone's gotta do it I suppose, glad he's a nice guy for your sake.
I ran a car lot in florida that was next door to one of these places. Every thursday afternoon and when the wind blew from the south, I was OUTTA THERE!

 

I do about 1-2 dozen of these type tours every year. Some are organized and some are not. I put this one in my top 10 along with the guts of the Hoover dam, Some aerospace companys, my two personal foundries and close down federal penitentiary’s.

My favourite are always personal unguided tuers with engineers or owners, where I can pick their minds, not under a script.

Maybe a little bit too morbid for you, but today I got to play with titanium hip and knee joints and see how they went together. For me, it was a little bit neat as I have made at least one of the joints I handled in my past. He stated 3800°F was pooling temperature for titanium. He rarely gets above 2600°F. Any gold or lead mixture is usually lost.

 

After walking a mile from the parking lot, we tried to do the Hoover dam, but the rentacop at the door gave my wife crap because she was carrying a bottle of water and a purse... We told them to shove their dam tour and watched it on youtube. Saved 50bucks too. That damn tour should be FREE.