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Dusty's Boiler and Auxiliaries Projects

Posted by frustrated 
Dusty's Boiler and Auxiliaries Projects
June 30, 2023 11:01AM
I have no idea what happened. We had three separate topics on the same project. To make future searches easier, I decided to merge the topics. I merged the first two without problem and when I went to merge the third, all three were erased. By clicking backwards through my browser, I was able to recover the text of the merged file -- but none of the photos.

If you could send the photos to my e-mail, I could reassemble the post.


Sorry about this, I honestly have no idea what happened.



This is my attempt to combine design elements of the SES boiler-burner with the basic burner design from a typical gas turbine engine (jet engine).


All tubing is 5/8" copper, with a length of 83 feet (25 meters) resulting in a surface area of 1963 in2.
As the drawing shows, burner exhaust gasses are directed through the super heat section of the boiler coils as the gases make their 180o turn and flow through the bulk of the boiler coils shown below:




This assembly is not yet finished, it's still a work in progress. I have not yet fired up the burner while it's inside the boiler coils; although my spark ignitor has been quite reliable thus far, I do not want to risk accidentally filling the boiler container with atomized diesel fuel before the burner ignites it, so, I will finish building the ECU (Electronic Control Unit), which uses a flame sensor to insure ignition, before I attempt to boil any water. Testing the ECU will be done with the burner outside of the boiler coils.

I pressure-leak tested the coils up to 100 psi,...(the pressure limit my shop air compressor will supply). I filled the boiler pot with water, and with the coils completely immersed, turned up the air pressure while I watched for bubbles,...there were none. I would prefer testing at 500 to 600 psi, but I don't have the equipment to do that.

I'm aware that the boiler coils are somewhat closer together than is typical, however, I am using a leaf blower to force the hot exhaust gases through the boiler coils at a pretty good clip, so I'm hoping that the hot gases will be well circulated despite the tight spacing. This tight spacing is an experiment for me, and I would very much appreciate hearing from those having experience with forced air boiler-burners such as mine.

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Dusty [ PM ]
Wobble Plate Air Compressor DIY new
June 28, 2023 08:37PM IP/Host:
Registered: 9 days ago
Posts: 3
The siphon-type fuel nozzle I use in my burner does a marvelous job of atomizing diesel fuel, but needs a nominal 4 to 6 psi air pressure to operate. This pic shows a "cloud" of diesel fuel which I intentionally did not ignite in order to take this photo:


These fuel nozzles need a smooth air flow, like you would expect to get from a compressor's air tank. Air flow taken directly from the output of a single piston or diaphragm pump consists of a series of pressure pulses which cause the same pulsing to show up in the burner's flame, which at low burn rates can lead to the flame going out.

Many automotive air conditioning compressors use a wobble plate (swash plate) to drive multiple pistons, resulting in a very smooth vapor flow. My problem was that the smallest commercial unit I could find was still way too big. So, I designed and built my own, shown running in this video:Wobble Plate Compressor

This chart shows measured performance when connected to the 2mm bore siphon nozzle:


Displacement per revolution is 6.8 cubic inches (111.4 cc).






Edited 1 time(s). Last edit at 06/29/2023 12:08AM by Dusty.
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Dusty [ PM ]
Jet Engine Inspired Burner new
June 28, 2023 08:31AM IP/Host:
Registered: 9 days ago
Posts: 3
Some years back I decided to build a light weight steam turbine capable of 100+ HP; this post (my first) describes & shows the burner assembly.
This video shows the burner running at a low to mid-level operation burning Diesel fuel: Burner Video

The simple drawing shows how the slotted burner can is located inside the outer stainless steel shell. Both of these parts were made form thin stainless steel cookware and drinking cups (notice the pot lid in one of the photos ). The below pics show the inner burner can assembly; the slotted tabs are pushed slightly inward so as to force the high speed air from the blower into a swirling pattern inside the combustion area. The slotted rings around the burner can assembly swirl the air flow between the inner and outer walls of the burner assembly providing the cooling needed to keep the inner combustion chamber from melting.





The brass nozzle is sold on eBay for use in "waste oil" burners; the one I'm using has a 2mm nozzle bore diameter and is rated to use 4 to 6 psi air to turn 14 liters/hour into a fine mist. In practice, I've successfully used up to 15 psi to burn significantly more fuel,...how much more I haven't yet measured. I've been told by some folks who use this same style nozzle in their foundry ovens that feeding pressurized fuel into the nozzle also increases the burn rate.

The two circuit boards generate the high voltage for spark ignition.

Fuel burn rate is determined by the air pressure fed into the fuel nozzle and the variable speed "leaf blower" supplying air to the burner and is fully variable from completely off to whatever the max burn rate turns out to be, (I'm guessing well over 30 liters/hr, perhaps even double that by using a fuel pump).

Notice the flame color in the below photo is blue-orange; blue indicating complete combustion, while the orange means my boiler tubes will still collect a bit of black soot.


Finally, below is a pic of my test set-up. The small round, black cylinder in the foreground is an electric motor which turns the metal colored cylinder via a timing belt. The metal colored cylinder is a wobble plate, 5-cylinder, 10-piston, air compressor which I designed and built to supply air flow to the fuel nozzle.

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