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Dusty's Experimental Boiler

Posted by Dusty 
Dusty's Experimental Boiler
July 01, 2023 02:38AM
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.





Edited 1 time(s). Last edit at 07/01/2023 07:45AM by Dusty.
Re: Dusty's Experimental Boiler
July 01, 2023 02:49AM
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 Comressor

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

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




Re: Dusty's Experimental Boiler
July 01, 2023 02:57AM
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.



Edited 2 time(s). Last edit at 07/01/2023 07:18AM by Dusty.
Re: Dusty's Experimental Boiler
July 01, 2023 03:39AM
This is a burner I experimented with burning five gal of oil per hour.
The power was 15 PSI of water pressure and acted as the fuel pump as well.
I never used it as I was working on several other designs at the time.
Rolly


Re: Dusty's Experimental Boiler
July 01, 2023 07:31AM
Very interesting! I especially like the wobble plate air compressor. Nice work.
Have a great day
Steve
Re: Dusty's Experimental Boiler
July 01, 2023 09:37AM
Rolly, is the boiler tubing inside the bluish ring ?
Re: Dusty's Experimental Boiler
July 01, 2023 10:07AM
No The brner went under my Derr Boiler.
Rolly


Re: Dusty's Experimental Boiler
July 02, 2023 03:16AM
You could make a simple water pump with non return valves to hand pressurise your coils then look for leaks.
Mike
Re: Dusty's Experimental Boiler
July 03, 2023 12:34AM
The Turbine

In this thread's first post I mentioned the burner-boiler would supply steam to a small turbine,...so here is that turbine. Try to overlook all the missing screws, I'm still adding the little stuff like a proximity sensor to read RPM, etc., so many of the pieces are held together with a minimum number of screws.
Doesn't look like much from the outside, but inside the housing is the 3 stage axial flow turbine:



Looking into the steam outlet, below left, you can see the 3rd rotor. The right pic shows 1st and 2nd stage rotors and the 1st stage stator blades.


The convergent-divergent nozzle shown below has 17 nozzles which have a 1.1" diameter and a 1.18 in2 outlet area. The most restricted section of each nozzle has an area of 0.0136 in2. Multiplying by 17 gives a total nozzle area of 0.231 in2 which is equivalent to a single 0.27" diameter hole.



The pic below shows nozzles, blades, and stators orientation along the steam flow path.


Re: Dusty's Experimental Boiler
July 03, 2023 03:24PM
Hello Dusty,

All I can say about your work is WOW!

You are way ahead of me with your boiler design because mainly, well, you are building one. That counts for a whole lot of credit.

I have become somewhat enchanted with the Velox boiler system, modified, of course. I can't leave anything alone.

It seems to me that you must have studied turbines quite a bit. So a question. I have run across some conflicting information. My potential design calls for a compressor output of 90 psi (gauge) and that is necessarily a multi stage. One source says that it should be an axial stage before a radial outflow stage and another says, no, a radial compressor stage before the axial.

I have not had the time that I really wish to devote to the proper study of this situation yet so - What's your take on it?

Welcome to the Phorum, I hope we will be seeing and hearing a lot from you.

Best Regards,

Bill G.
Re: Dusty's Experimental Boiler
July 03, 2023 10:06PM
Hello Bill G.

First, I'm just an old, retired electronics engineer that during my career worked on the electronic controls for several gas turbine engines and managed to pick up a little knowledge about jet engine physics along the way.

You can find example engines for both of the compressor arrangements you mentioned; both work, and I don't believe one method is better than the other. However, you only need a single centrifugal stage to reach 90 psi if you use a stainless or Titanium impellor. Nearly all automotive centrifugal impellors used in turbochargers are made from aluminum, and provide a max pressure increase of 4 to 1 or 58.8 psi at sea level. The 4 to 1 max limit is because the compressed air becomes hot enough to cause aluminum impellors to loose enough strength such that they can no longer handle the centrifugal stresses at those elevated temperatures. But, both stainless and titanium can handle much higher temperatures without loosing too much strength, so those impellors can provide 8 to 1 pressure ratios (117 psi); meaning you only need a single centrifugal impellor to get to 90 psi. A few after-market turbocharger companies are selling impellors made from a single block of metal, aluminum and I believe stainless, CNC machined.

Finally, I've read that some race car fanatics use dual turbo chargers, one feeding into the other, to get 150 pounds boost.



Edited 1 time(s). Last edit at 07/03/2023 10:51PM by Dusty.
Re: Dusty's Experimental Boiler
July 06, 2023 10:07PM
Hello Bill G.

I don't believe you'll be able to run out to your local compressor supply store and buy one of these, but I wanted to show you the potential of centrifugal compressors. Some very clever researchers using CFD (Computational Fluid Dynamics) have designed a single stage centrifugal compressor capable of 14 to 1 pressure increase,...that would give you 205 psi at sea level from a single compressor stage. link: 14:1 Single Stage
Re: Dusty's Experimental Boiler
July 14, 2023 09:40AM
Managed to buy a hydraulic jack unit on sale and put it to use accomplishing a hydrostatic test on my monotube boiler. The Normal Working Pressure will be 500 psi so I tested the boiler to 1000 psi. There was no ballooning of the annealed brazed connections, indicating that 1000 psi had not exceeded the yield limit. Factoring in 80% strength for copper at 200 C gives me 800 psi just to get to the yield pressure, not the burst pressure. Not bad for copper tubing.


Re: Dusty's Experimental Boiler
September 13, 2023 12:27AM
ECU Progress Report:

As I mentioned a few posts back, my Burner-Boiler will be computer controlled; boiler temperature and pressure outputs will be continuously monitored and fuel, burner air flow, and feed pump will all be automatically adjusted to maintain the desired power output. To that end, I've designed and have been building the ECU (Electronic Control Unit) which uses an Arduino Mega 2560 micro-controller to monitor all the various sensors and adjust electric motor speeds which control air & fuel flow into the burner. I've placed all the various electronic boards inside a decades-old Dell PC mini-tower chassis shown below.



The necessary burner components are laid out a test bench while I write and test the software for the Arduino 2560.



The plastic box below simulates the various sensor voltage levels allowing me to input to the computer different temperature and pressure levels without actually running the burner or boiler. This allows me to write the software which will ensure the ECU will not allow an over-temperature or over-pressure condition to ever happen; all while the display screen shows parameters such as Boiler Temperature In and Out, Boiler Pressure In and Out, etc.


Re: Dusty's Experimental Boiler
September 13, 2023 07:15AM
Dusty,
Nice work.

I re-posted your pictures of the nozzle and design. I think of this design to be pretty good. It looks like a great idea.

Wondering if you have some data or observation on how well the converging-diverging nozzle design works? Any idea what your Reynolds number is at your conditions? More over, wondering if you maintain laminar flow. Then, with laminar flow, the 2nd and 3rd stages make sense. If not laminar, then the later stages are not worth while.

Reason I say this and after the post earlier is that, I was just talking with Tony Grzyb about his turbine design and experimenting. He performs development in a much less formal manor. However, he has some interesting turbine developments worth mentioning. He noticed that there was no improvement with adding a 2nd stage with his turbine. His nozzle is not converging-diverging to just focus on turbine blade form development. My thought is that a converging-diverging nozzle would cause more turbulence, in its effect, if not in the lower Reynolds No.

On another note, turbulence is your friend when in boiler design. The higher the number, the better the heat transfer. The bigger the blower the better...might be counter productive to the turbine. Everything is a balance.

It's fun figuring these things out.

Kind regards,
Rick


Re: Dusty's Experimental Boiler
September 13, 2023 09:49AM
Hi Rick,

My decision to use CD nozzles is based on the many research studies I've read over the years, which all state their benefits.

I have no idea what the Reynolds numbers are through the nozzles or through the blades and stators, however, I have attempted to insure a laminar flow through the entire turbine. This has been accomplished primarily by insuring the angle of the turbine walls are 7o to the axis. Consider that if you were to pull all the blades and stators out of steam turbine, you're left with a divergent nozzle. If you keep the diverging angle at 7o or less, your turbine is almost assured to have laminar flow. If the diverging wall angle is 10o or more, than the turbine will almost certainly have turbulent flow. Here's a short study on diffuser angle and it's affect on flow separation: DiffuserAngle.pdf

I don't know Tony Grzyb nor anything about his turbines; does he post his projects anywhere on the internet? However, just noticing the high number of blade-stator rows in most any steam turbine used in power stations should tell us that a single row of blades is not a very efficient turbine,...and a little physics will verify that observation. Still, I applaud anyone designing and building their own turbines, regardless of their efficiency.

My use of CD nozzles is only a small part of the overall turbine design; blade and stator design is equally important. Steam flow velocity and pressure are both constantly changing as the steam progresses through the blades and stators. The first row of blades are almost entirely impulse while blade rows 2 & 3 are combined impulse-reaction. Steam velocity through the first row of blades changes very little, however, notice how large the inlet area of the stator blades are compared to the exit area. Steam entering the stators slows a bit as it expands, thereby increasing pressure, which is then forced through the smaller area at the blades exit, which lowers the pressure while increasing the velocity. This high velocity steam now impacts the leading edges of the second row of blades resulting in energy transferred into the blades via impulse (or impact, however you want to think about it). As with the stator blades, the inlet area of the rotor blades is much larger than the exit area, resulting in the steam exiting the rotor blades at much higher velocity than it entered, thereby creating a reaction effect on the rotor blades.

Dusty



Edited 2 time(s). Last edit at 09/13/2023 08:21PM by Dusty.
Re: Dusty's Experimental Boiler
September 28, 2023 12:40AM
First test run of the ECU controlled burner was a complete success.
Below is a pic of the outdoor test stand showing all the components mentioned in my "ECU Progress Report" post above.


Burner & ECU function test

In the video, after I press the start button, about 3 seconds was required to suck fuel (B7 Diesel) into the burner and ignite it. The flame is detected and the ignitor is turned off. At 19 seconds into the video an unexpected air bubble in the fuel line caused the flame to go out, which the sensor instantly noticed resulting in the ignitor being turned on until the fuel is re-ignited, followed by flame detection and ignitor once again being turned off. That sequence took only 1 second, for which I'm very pleased as I was concerned that a flame-out might possibly result in a cloud of unburned fuel mist blown into the boiler where it could explode or at least result in an unpleasant pop.

Almost immediately after the re-ignite cycle, the ECU increases fuel and air flow, as it was programed to do, in order to increase boiler heating. The increased power output continues until I turn the “Pressure Out” up to a setting above 20 (an arbitrary number chosen for test purposes). At this point the ECU regulates the power output based on the manual input, “Power Request”, which I turn up to about 23% before I press the OFF button.

After the start-stop button is pressed, fuel flow is turned off while the air blower remains on at 10% to blow excess heat out of the combustion chamber, which is done to prevent the plastic flame sensor from melting due to latent heat within the metal parts of the combustion chamber.

Next tasks to accomplish before placing the burner inside the boiler: wire up the boiler feed pump (a pressure washer) and write the software to control it.
Re: Dusty's Experimental Boiler
October 11, 2023 09:43AM
Adjusted the burner's air-fuel mixture to get the most blue flame at medium to high burn rates, which is now done through software changes.
Fuel is diesel B7 at about 80% power level. The photo was taken at night with minimal outdoor lighting.



I've posted a video on YouTube: Night Burner Test

Getting closer to being able to boil a little water cool smiley
Re: Dusty's Experimental Boiler
October 11, 2023 07:46PM
Dusty, very impressive looking! I'm far behind on deciding exactly how my boiler will end up. Too many ideas , too little time, and most of my time has gone toward overall design especially the expander.
Thanks for posting. I look forward to seeing your finished design.
SteveW
Re: Dusty's Experimental Boiler
October 25, 2023 07:01AM
Successful boiler test today. For this first test, the boiler was connected to a water faucet in my front yard and the steam's 5/8" (16mm) output end was left open to avoid any accidental pressure build up; the purpose of this test was only to make steam, and to get an idea of how much steam was being generated. No pressure or temperature gauges have been installed at this time. These two photos show the test table,...



Steam!!


A one minute long video of the boiler's first test run is here: https://youtu.be/rjPUE-RhNXU
Re: Dusty's Experimental Boiler
October 25, 2023 07:43AM
This looks very well executed, my congratulations.

On a humorous note, I know of an instance where one individual built a monotube and complained that he couldn't get it to raise steam above 40 psi -- no matter how hard he tried. One of the club members visited him and found out that the water supply was a garden hose...and so all the pressure buildup was moving backwards into the house plumbing. If he had just shut off the spigot, he would have gotten lots of pressure -- fast! It might be hard on the hose, but that's life...
Re: Dusty's Experimental Boiler
October 25, 2023 09:27AM
frustrated Wrote:
-------------------------------------------------------
> This looks very well executed, my
> congratulations.
>
> On a humorous note, I know of an instance where
> one individual built a monotube and complained
> that he couldn't get it to raise steam above 40
> psi -- no matter how hard he tried. One of the
> club members visited him and found out that the
> water supply was a garden hose...and so all the
> pressure buildup was moving backwards into the
> house plumbing. If he had just shut off the
> spigot, he would have gotten lots of pressure --
> fast! It might be hard on the hose, but that's
> life...

Well, I guess we know the water pressure in his house was 40 psispinning smiley sticking its tongue out

But you bring up a question I've been pondering over for many weeks; what feed pump should I use, and do I actually need two pumps?
I'm considering using a small 12 volt pressure washer pump as a "starter" pump to get boiler pressure up to about 100 psi, then use a steam powered pump to supply more water at 500 psi.

I believe the SES auto used a 3-piston pump powered directly by the piston engine and needing several HP to run. My engine will be a turbine spinning at 60,000+ rpm, making engine take-off power shafts to drive a piston style feed pump mechanically challenging. So, if I want to use a single pump, I also need a rather large, heavy 3 to 5 HP electric motor to spin it.

What feed pumps are other steam cars using?
Re: Dusty's Experimental Boiler
October 25, 2023 12:27PM
Generally speaking, most steam car feed water pumps are mechanically driven from the main engine. Some of them built in the 70s used off the shelf CAT pumps. Cars like Stanley's had piston pumps of their own design. Doble pumps looked fairly sophisticated with 3 pistons, magnetic solenoid unloaders, and so on.

The attached drawing shows that the Stanley had two single acting pumps operating of a crosshead in the middle. The stroke looks rather long compared to bore, which ondoubtedly kept leakage to a small value. There is also a single acting fuel pump on the same assembly, so the water and fuel were being pumped at a constant proportion, with delivery to be regulated by automatics. There was another hand pump to prime the boiler for light off.


Re: Dusty's Experimental Boiler
October 27, 2023 09:06AM
From experience, the temperature and pressure rise at the same value or very close to the same value. So it is easy to measure the exhaust temperature and have a good idea of the pressure. As the Professor (team member), this is the advice I gave a gentleman who is seeking a land speed record.

Super Secret Boiler

I actually recommended preliminary testing using a garden hose. Results did teach us a lot about how well the boiler performs.

I have to thank Tom Kimmel for asking me to ride in his mono-tube powered buggy at a steam meet. We rode together at the fairgrounds and in time trials. I was the computer trying to figure out to control the feed water while he drove. The observation with this experience is that the temperature gage and pressure gage rose at the same values. Readings were at 800-800, then 900-900, 1,000-1,000, 1,100-1,100 and 1,200-1,200 temperature and pressure respectively. It was at this point that the engine intake manifold brew off with a spectacular bang. This was one of the best times I had at a meet smiling bouncing smiley let alone one of the best learning experiences.

Through the ages and including Serpollet, there always have been a large feedwater pump to provide the pressure needed to get the steam pressure out. The Easter egg had a steam driven pump as big as the drive engine. It did set a land speed record at the time.

Gardner-Serpollet Wikipedia for quick reference

Working with figures from Chuk (Land speed record for a steam piston powered car), the pump needs to produce 25% to 35% more pressure than you get out. Hope this helps...and fun to watch.
Re: Dusty's Experimental Boiler
October 27, 2023 08:53PM
Thanks Rick.H, your recommendation of needing 25% to 35% more pressure from the feed pump than the boiler output pressure is useful information.

Thanks Frustrated for noting that some '70s steamers use off-the-shelf CAT pumps.

Using both of your data, I've done a few back-of-the-envelope calculations. The burner I've built can burn 28 liters of Diesel in one hour, which equates to 1,018,679 BTU = 400 HP = 300 KW. A huge unknown is whether or not my boiler can convert most of those BTUs into steam. But I need to start somewhere, so lets assume the boiler is 100% efficient. Using one BHP (Boiler Horse Power) = 13.155 standard HP, means my boiler would be rated for 30.4 BHP.

Using the flow rate formula: BHP x 0.069 = GPM (gallons per minute),

30.4 BHP x 0.096 = 2.1 GPM = 8 LPM.

So, assuming 100% boiler & burner efficiency, my feed pump needs to deliver 8 LPM (liters per minute).

I've previously decided my boiler will operate at 530 psi max; adding 35% results in 715 psi, which is = 50 bar. So the feed pump needs to deliver 8 LPM at 50 bar, (2.1 GPM at 700 psi).

Many home-use, electric pressure washers exceed those requirements, and they're relatively inexpensive. I could vary the electric motor's rpm to control flow rate, but these pumps are all plunger type, meaning they're constant pressure at all rpms, so changing the pressure at the pump would be a challenge.

Gentlemen, am I on the right track?
Re: Dusty's Experimental Boiler
October 28, 2023 02:03PM
For a small boiler, a good starting point is to assume that the boiler is about 80 percent efficient - there's practical limits to how much you can insulate the boiler casing and how much heat you can extract from combustion gasses. For instance, reducing stack gases to feedwater temperature would require an infinitely large economizer. Abner Doble claimed the Doble-Detroit boiler was 90 percent efficient and gave data to back this. The thing was that the data showed that the feedwater tank was probably outside on a cool Detroit day and so the feed water temperature was cool -- meaning that the gases leaving the boiler were cooler. The problem was that the car used a condenser and the feed water temperature leaving the condenser would be close to boiling temperature, making it impossible to reduce stack gases to the same low values.

There is a useful term called equivalent evaporation which is used to compare boilers of different specifications, giving an honest comparison of their capabilities. I have only seen it once used in relation to steam cars, by the Baker Steam Car and Manufacturing Company of Pueblo, CO. It actually showed that their boiler was just so-so, but most readers probably couldn't decipher the results and assumed that the results must have been really favorable if they took the time to have independent tests made and published.

Honestly, boiler horsepower is a pretty obsolete measurement and wasn't universally accepted even when it was common simply because of the wide range of engine efficiencies.

I think the better way to calculate this would be to determine what boiler pressure and temperature you want to maintain and then figure out how many BTU this constitutes in whatever unit of measure you prefer. Multiply your burner output by about 80 percent and then divide by the BTU per unit to determine units per hour.

Regards,

Ken



Edited 1 time(s). Last edit at 10/28/2023 05:12PM by frustrated.
Re: Dusty's Experimental Boiler
November 02, 2023 09:34AM
Yes Dusty, you are on the right track. You are at a good starting point.

I started the same way with my steam powered scooter design. Be careful you don't fall into analysis paralysis. Beter to go with your design with a prototype or a test of a mono-tube in action. Measure your results and equate to your design.

One SACA Meet I brought a 3/8 OD copper coil (called an Ofeldt coil) with wire spiraled inside like a rope. I brought my Coleman liquid fueled camping stove, a #10 can and a couple of fittings and valves. The intent was to test my concept of using fill within the boiler tube or generating tube.

I substitute teach at my local High School and generally take on Technology, Math (Geometry), Sciences and round it off with Social Studies along with Art; and Gym. One main thing I emphasis is failure. The breakdown of FAIL is first attempt at learning. I'm at school now writing this response, free period of course.

My tube experiment mentioned above was a failure in my mind. I was testing the tube as a natural circulation tube as used within an Ofeldt Boiler. The benefit with fill within a tube is really good for forced circulation or force feed. Hence my new Ofeldt design includes more forced circulation (forced feed) to the generating tubes. Hope you see where I'm going with this example.

Hope this is useful information. You want high Renolds No. indicative of turbulence within the tube. I did a quick calculation using some values from the internet to find that heat transfer goes up exponentially with the increase of turbulence. When you get to this point in design and experimentation, you may very well find out why it is not useful to work with boiler horsepower and move to a more commensurate set of units.

Proceed with vigor my friend,
Rick
Re: Dusty's Experimental Boiler
November 03, 2023 08:17PM
I'm not sure if I had fallen into analysis paralysis, or if I was just being indecisive, but I've spent much of the past 5 days trying to decide, what is the best feed pump design for my project. I finally concluded that my best option is to use two separate pumps; a small electric pump will ensure the tubes are full of water before the burner is ignited, and also provide enough pressure to allow the boiler to generate sufficient steam to power a separate steam powered feed pump. I had previously been focused on using a positive displacement pump, likely an electric pressure washer, but the large size, large weight, and the need for a large motor electronic controller needed to vary pump speed and flow, pushed me to keep looking for other choices.

I finally realized that today's electric fuel pumps should work nicely. The high pressure automotive fuel pumps I plan to use are rated to deliver 5 liters per minute at 100 psi. This alone should be sufficient to generate enough steam, at pressure, to run a small steam powered feed pump, at which time the electric pumps can be turned off. I will also try running two of these pumps in series in an attempt to double the pressure output up to 200 psi. From what I've read on the internet, a few race car enthusiasts are running two high pressure pumps in series to boost fuel pressure to the engine; hopefully this is a good indication that I wont burst the second pump due to over-pressure.

If the Osias provided chart, shown below, is accurate, their pump should provide 260 LPH (4.33 LPM) at 120 psi. Two pumps in series should theoretically reach 240 psi. I ordered two pumps from China,...should be in my possession in about 2 weeks. I'll keep readers posted as to how well they work. I'm very impressed with how well these pumps are designed and built using a tiny impellor as the pump. I've posted the internal parts drawing below.




Re: Dusty's Experimental Boiler
November 04, 2023 06:18PM
Dusty, good looking design. I've been dithering along for years myself.
I have a question though. What temperature do you expect to
encounter with your pump? The system I'm working on will reach over 500F
. Your burner really is interesting. I am looking forward to seeing your system fully working

SteveW
Re: Dusty's Experimental Boiler
November 04, 2023 09:45PM
SteveW, In my design, the Osias feed pump is used only during initial start-up, to pump water from the reservoir tank into the boiler tubes and then to supply enough feed pressure into the boiler to produce enough steam pressure to run the primary steam-driven turbo-pump. Once the turbo-pump is operational, the Osias pump will be turned off. So, most of the time, the Osias pump will be pumping ambient temperature water.

However, my overall engine design is a closed system using condensing coils to cool the steam back into water; so, there will likely be times when a re-start occurs shortly after a shut-down resulting in the Osias feed pump pumping water at just under 212oF.

I searched the internet for max operating temperature of the Osias fuel pumps, and came up empty, however, my thinking is that automotive engines typically operate above 212oF, and a common location to mount an external fuel pump would be under the hood, next to the hot IC engine,....so surely these fuel pumps can withstand 212oF. I know I'm getting into uncharted territory, and I'll just have to try it myself to determine whether or not these Osias fuel pumps make good feed water pumps.

Now, if you're thinking of possibly using one of these Osias pumps to circulate pressurized 500 degree water through boiler tubes,... then you're deep into uncharted territory.



Edited 1 time(s). Last edit at 11/04/2023 09:49PM by Dusty.
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Al Wobble Plate Pistons b.jpg 259.7 KB open | download Dusty 07/01/2023 Read message
Al Wobble Plate Reed Valves a.jpg 280.7 KB open | download Dusty 07/01/2023 Read message
Al Wobble Plate parts a.jpg 213.2 KB open | download Dusty 07/01/2023 Read message
Al Wobble Plate assembly d.jpg 277.6 KB open | download Dusty 07/01/2023 Read message
Boiler Burner dwg.JPG 197.9 KB open | download Dusty 07/01/2023 Read message
Boiler Coils a sml.jpg 614.1 KB open | download Dusty 07/01/2023 Read message
Boiler Coils top sml.jpg 745.6 KB open | download Dusty 07/01/2023 Read message
Boiler Burner assy sml.jpg 517.8 KB open | download Dusty 07/01/2023 Read message
P1010004b.JPG 131.4 KB open | download Rolly 07/01/2023 Read message
P1010007.JPG 86.4 KB open | download Rolly 07/01/2023 Read message
Spider & Turbine Assy sml.jpg 276 KB open | download Dusty 07/02/2023 Read message
Turbine Parts sml.png 722.9 KB open | download Dusty 07/02/2023 Read message
Turbine Exhaust End sml.jpg 535.6 KB open | download Dusty 07/02/2023 Read message
Blisks & Stator.png 760.5 KB open | download Dusty 07/02/2023 Read message
Nozzle c.jpg 220.2 KB open | download Dusty 07/02/2023 Read message
Steam path thru blades.png 18.2 KB open | download Dusty 07/02/2023 Read message
Boiler Hydro test d sml.jpg 245.3 KB open | download Dusty 07/14/2023 Read message
ECU mini-tower sml.jpg 440.3 KB open | download Dusty 09/13/2023 Read message
ECU Test Bench 2 sml.jpg 322 KB open | download Dusty 09/13/2023 Read message
Display & Test Box sml.jpg 376.7 KB open | download Dusty 09/13/2023 Read message
Nozzle.jpg 5.5 KB open | download Rick.H 09/13/2023 Read message
Steam path thru blades.png 18.2 KB open | download Rick.H 09/13/2023 Read message
Diffuser Angle.pdf 823 KB open | download Dusty 09/13/2023 Read message
Burner Software Test Stand sml.jpg 309.9 KB open | download Dusty 09/28/2023 Read message
Blue Flame.JPG 54.4 KB open | download Dusty 10/11/2023 Read message
Boiler test #1.JPG 51 KB open | download Dusty 10/25/2023 Read message
Test Table, Boiler a sml.jpg 361.2 KB open | download Dusty 10/25/2023 Read message
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Stanley pumps.png 65.9 KB open | download frustrated 10/25/2023 Read message
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Water%20thermal%20conductivity%20F.jpg 126 KB open | download Rick.H 11/14/2023 Read message
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Cordless Pressure Washer.png 40.6 KB open | download Dusty 12/17/2023 Read message
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36VDC Feed Pump top view.jpg 827.7 KB open | download Dusty 01/06/2024 Read message
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Boiler Input Sensor Block sml.jpg 179.8 KB open | download Dusty 01/31/2024 Read message
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Sensor Block Exploded View sml.jpg 388.2 KB open | download Dusty 01/31/2024 Read message