Gear-pump pressure nozzle burner

I ran a Beckett style burner on my crudely modified MIFCO B-16 furnace (I did not get the OEM burner with it, and was tired of keeping propane tanks in water baths with my DIY forced air burner)
One thing to note is the delavan pressure nozzles do not like to be sitting inside a hot furnace. They will coke up if left exposed to heat long enough. During operation the airflow+ fuel was sufficient to keep nozzle temp down.

My solution for this was to quickly withdraw the burner assembly from the furnace as soon as furnace operation were complete. In my head I had designed a lever to withdraw the burner & drop a heat shield down across the burner socket but I never got that far with it, and I have not run that furnace in many years at this point.

Might I ask why you have not started with a Beckett burner as a base? The blower, motor, coupling, ignition & electric eye safety features are all there in one somewhat convenient unit. Often can be found for free or dirt cheap on the Craggles or Marketplace in used but serviceable condition.
Starting my furnace was as simple as flipping a light switch. (on a good day when I didn't have to bleed the fuel lines)
Consider adding some plumbing fittings for priming the pump + bleeding the pump if you separate your fuel tank from the burner

 

Hi
Thanks for the tip about the nozzles coking up.

Where I live (New Zealand) liquid fuel heaters are rare and a quick Google search tells me there are no Beckett agents or burners here (new or used). I have never before heard of Beckett. Even if I could get one, they will be the wrong voltage (220V).

For less than the price of an air compressor, I have found burner units on Aliexpress. Quality/suitability unknown.

Dazz

 

Thank you for answering some of the questions. You have 220 V single phase at hand.

But now I have more questions.

Are you “only” going to be running diesel as a fuel?
And you are “not”, considering “any” compressed air in the whole working set up?

 

Hi
If I can avoid buying/running a compressor, I would be happy to be restricted to running diesel.
Avoiding the need for a compressor is a goal worth seeking. They are expensive, use lots of power (=$$) and are something else to go wrong.

Dazz

 

Every shop needs a compressor. I bit the bullet years ago and bought a big one. Once you have it, you'll wonder how you managed before. They dont use lots of power unless you run it all day. Mine hardly runs when I use it to move diesel for my burner. 15psi is all and it's very low volume to run the venturi. I see you are in Oz dazz, so your results may very. After all, your toilets are confused, be sure you point your burner the other way around too....

 

The rule of thumb in hydraulics is a 1 Hp electric motor displaces 1 gallon of fluid at 1200psi. In 1 minute.
An automotive oil pump moves several gallons a minute.
The heat is caused by inefficiency. The oil is compressed storing the energy then is released as heat generated by friction in the regulator and any pump slip or system resistance.
The pump is positive displacement minus any slip. If this pump was designed to pump motor oil. It will have more slip when pumping less viscus fuels. How much is unknown.
You are delivering a lot of fuel at a low pressure. If you remove the spray nozzle and crank the regulator tight. How much fuel are you pumping in a given length of time?
Whatever the ratio is of fuel pumped to fuel needed would be a good point of reference. You might pump several times the volume you will use in the burner after pump slip at very low RPM
I have a feeling that if the pump was driven at 200 to 300 RPM with a .1 Hp motor. It would be plenty.
Joe

 

Lol. Or maybe three or four. I have three in my shop. Two in my basement shop and one in my truck.

I have an 5hp, 80 gallon in my shop that is on pretty much 24/7(I unplug it to use the welder). With small grinders and pneumatic nailers, I just couldn’t imagine trying to shove a 2 inch 18g pin nail into a piece of wood using a hammer.

 

There are several options available for running without a compressor. I happen to use a compressor and Delevan "siphon" nozzle, but pressure nozzles can be run from any number of pump types as discussed for the last 3 pages here. An example is Topendscraper over at AA. He had a successful adventure with a fuel injector pump.
http://www.alloyavenue.com/vb/showthread.php?7647-Diesel-burner
In order to keep things even simpler and/or less expensive you might consider a brute style drip burner fed either by gravity or a peristaltic pump (also known as a dosing pump). That won't atomize your fuel, but once your furnace is sufficiently preheated with propane it doesn't need to be. It would open the door to other fuel options as well.

Pete

 

The only shop compressors I know that aren't worth spending any money on is the one's that are "oil-less" TOTAL JUNK! I call them air-less. They are NOISY and will fail when you need it most.
Give me an old school, oil leaking, chug chug chug shop compressor any day. We have a 3 phase in the hangar that's 60+ years old and receives ZERO maintenance and she just keeps putting out more air than we will ever need. If you are dragging a compressor around to job sites, that a different story. Bring a long cord and leave the noisy bitch outside.

Rasper runs an oil burner and uses gravity as the motive force for moving the oil. He hauls the fuel container up a flag pole and doesn't need compressed air. You might look at his setup Dazz. You can skip the nozzle all together that way!

 

Hi Joe, It's all a bit of a compromise arrangement that just happens to work, there's no doubt that the flow rate could be optimized but it was lying around handy. The pump normally runs off the camshaft so would typically run at half engine RPM so say 1000 RPM normally. I'm using a lot of kerosene which is pretty low viscosity so when I drive the pump at 720 RPM it's flat out producing 50 PSI. So for a 40 year old, worn, low precision pump with low viscosity liquid I have to run a certain minimum rev range. When running a half horsepower motor the current drawn indicated about 0.6Hp at 1440 RPM.

 

I like to think of it in millilitres per minute. It’s easy to measure.

I found diesel to be very difficult to burn. I did some tests with a small Diesel pump that ran off 24 VDC. It worked great with diesel. When I switched the feed to WVO it just choked. I did as many tests as I could trying not to use pressurized air. But... I didn’t try a gear pump. I wanted everything portable and easy to plug into a common North American plug (120 VAC 15A). I have two different properties. I do have a welding plug (240 VAC 40A) at both properties but, my goal was to keep it somewhat simple. I wanted diesel for the start up fuel and switch to WVO (as I discovered I can get it for free). I am running 2 torches so I can switch One of the two to WVO about two minutes in. Within five minutes I can have them both burning WVO. I’m working with high air velocity through my blower though.

My drip feed is somewhat of a small stream through a 1/8 ID tube. My goal was to get about 100 mL/m (3-4 fluid ounces per minute) per torch. So, I shot for double 200 mL per minute. But, I found if I was only using one torch, I didn’t have enough air. I had two 90° corners that I wanted to get rid of and increase the air volume. My old torch is work just fine, but they were running at full capacity of air. So I got rid of the two 90° and replaced it with one 30° And took the ID of the burn tube from 0.328” to 0.5”. This should give me three times the amount of air which I can choke back using a ball valve if need be.

I fully support anybody keeping something simple. Sometimes simple is just what you have access to.

 

I build a drip-style oil burner that was exactly like the one ironsides uses, and I could not get it to work right at all.
For the short period of time that it was working somewhat, it was surging all over the place, and not easy to regulate.

I noticed that Clarke's burner surges quite a bit (he uses an Ursutz), and he gets extremely hot iron, but still has problems with overheating and failing plinths.

What I consider the bible on oil burners is a paper written by the chief engineer at Delavan, and he goes into great detail about oil burner types, cone shapes, solid cones, hollow cones, fuel viscosity and how that affects fuel flow, droplet size, etc., etc.
The white paper is called "Fuel Nozzles for Oil Burners" by E.O. Olson, chief engineer of Delavan fuel metering products operation.
I will try to attach it here.

I really think the gear pump and pressure nozzle that I detail on the first page of this thread will work well, especially with the automotive size spin-on fuel filter, and diesel (I run diesel only).
I know the gear pump arrangement works well in general because that is the same gear pump that is used on virtually all oil heating units that use the pressure nozzle system.

The trick will be to get the right nozzle that works well with a furnace.
I think I went with a solid cone nozzle.

So if you like the drip-style burner, and don't mind a little surging, and don't mind perhaps adjusting it from time to time throughout the melt, and can get it to work (I could not get mine to work without it dribbling and puddling in the furnace), then it is as simple a burner as you can get, and does not require an air compressor.

I removed the o-ring from my Delavan siphon nozzle, and it works extremely well, but requires an air compressor.
I think my new screw-pump Delavan will work well, and it will eliminate the air compressor and the o-ring.
Screw pumps are relatively cheap (compared to air compressors), and I will probably build two units, and keep one as a spare.

.

 

That book on fuel nozzles is an interesting read: it turns out that lower flow rate nozzles have a smaller droplet size. So when I used 8 small "mist" nozzles it turns out that was the right thing to do to get a finer spray.

 

But as I recall, Olson said that finer droplets does not equal a hotter flame.
Check me on that.

.

 

But it should allow for faster combustion which is an issue for fuel oil compared to gasses.

 

The combustion process inside a heating unit, or a furnace, is not as simple as you would think.
Conventional wisdom does not always apply.
I posted a link to a white paper here that showed a guy pulsing the pressure to a siphon nozzle burner and increasing the efficiency by 30 %.

Its about creating the largest surface area of the hottest part of the droplets.
I will look at Olson's paper again and see if I can spot the part about droplet size.

.

 

The below items paraphrased from Olson's white paper:

When the viscosity of the fuel increases, the flow rate through a pressure-atomizing nozzle increases.
You would think the opposite would be true, but it is not.

If a burner is started with cold oil, and then the oil in the tank is heated, the burner discharge rate will decrease with the warmer fuel.

Surface tension of the particular liquid used affects the droplets.

The boiling range of the fuel affects the flame length and the flame front distance from the end of the burner tube.

High viscosity fuel produces larger droplets in a spray than low viscosity fuel at the same pressure.

Increasing the fuel pressure on the nozzle reduces the droplet size.

Nozzle design is a very important determinant of droplet size in the spray.
The smallest possible droplet size is not necessarily the most desirable.
Good droplet size distribution to produce efficient, quiet fires is determined by nozzle design.

.

 

Pat, I’m glad to see you’re back.

I tested fine droplets to spitty spray. The spitty spray with diesel and oil actually work better for heat and flame but not as good for lighting.

It is the hot face that vaporizes the fuel with a flash. Keeping the heavier droplets circling in suspension weren’t easy.

 

I've been on "vacation", but the "SV Debacle of 2020" (as it came to be know) warranted comment, or so I thought at first.

I played around with compressed air pressure on my siphon nozzle, and started by using 100 psi.
It seems like the burner runs hotter with the air pressure at 30 psi or less.

Like someone described, the droplets burn like a candle flame.
There are cool inner parts, and much hotter outer parts.
As the pulsed fuel pressure guy mentioned in his white paper, the idea for the hottest oil burner burn is to maximize the hottest part of the flame, and maximize the surface area of the hottest part of the flame.

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