Advice on a boiler burner

[camoura]

Hi,
I'm constructing a vertical boiler based on a Myfordboy youtube video ( 3"diameter x 5" height ) and I'm planning to use a gas burner.
I'm using a portable camping stove with a 75% butane 25% propane gas castridge.

I'm don't know if the high temperatures of the flame could melt the silver soldering. ( I did some tests placing a silver solder wire direct over the flame and it melted ). Also the gas valve does not offer a good control of the gas flow so it's dificult to adjust the flame specially near the low side.

Is this set up ok? Could anybody give me advices on burner choices for this set up?

Thank you very much.

Cheers from Brazil

Carlos Moura

 

[mfrick]

It will take a lot of heat to melt the silver solder joints due to the fact that you will have water in the boiler and the mass of the boiler will be a large heat sink dissipating the heat very rapidly, try to melt a joint that has been silver soldered and you will see that it takes a lot of heat, just melting the silver solder by its self is fairly easy.
Mike

 

[Gerald Pierce]

Hello Carlos,
Another option is ceramic burners. I purchased two from Stuart Models, www.stuartmodels.com

Photo below shows a round burner under a small boiler I built.

 

[Tony Bird]

Hi Carlos,

As has been mentioned if your boiler has water in it the solder won't melt even if it was soft soldered. Try repairing a soft soldered joint in a water system that has water in it. Not sure it will help you but I have just posted in this section on a boiler and burner build I am making.

Take care Tony.

 

[Steamchick]

Hi Carlos,
The photos in this thread look good. I have been making boilers and burners for many years off and on. Silver solder melts typicallying at 630C and above depending on the alloy. That is a dull red heat. When soldering a boiler I use 2 or 3 blow-lamps, and the boiler is 3/4 buried in sand or enclosed in a fire-brick oven. I doubt you camping stove could melt a joint if you have water in the boiler. Where is the water level gauge?
Properly designed joints will be at least as strong as the copper, so should never fail in a wet boiler..... except if in regions where the water cannot reach... Many loco boilers fail at flue tube joints high in the firebox, when at full pressure and the water is allowed to drop below the top of the firebox.
In your vertical boiler, the top of the firebox is below the water so cannot overheat.
A couple of points:

1. A proper boiler has proper plans, calculated material thicknesses, silver soldered joints, an hydraulic test at >2 times the Normal Working Pressure, a steam test to show pressure of NWP + 5% cannot be exceeded when the safety valve has lifted, of its own accord, and at least the following safety devices. Safety valve, water level gauge, pressure gauge, water pump. Then you can get it certified. It should also have a clack valve, blow-down valve, blow-down on the water gauge. It can have other things, more like a full-sized boiler. The fun is making all the parts that make a boiler a "proper job".
2. Lag the boiler - 90% of your heat is lost warming the room if you have no lagging. My standard, from boiler copper outwards: startvwith a sheet of paper. Next is aluminium foil, shiny side out. Then corrugated cardboard, 3 to 6 mm thick. Then more aluminum foil, shiny side inwards. That is the scientific bit of insulation. Then a "pretty" cover made from slats of wood. I used Balsa, easy to work and excellent insulation, from 3mm to 12 mm thick. The balsa can be stained to imitate a darker wood, then varnished and a couple of copper or brass bands to finish the "pretty" appearance.
3. Lag the pipework. I use cotton string, wound around all the pipes and finally painted with white emulsion paint. It looks like proper industrial pipe lagging and keeps the steam hot!
4. The Camping burner you have is a good start. If the power is too small (your engine slows when on full gas) then try a ledger burner until you have flames cming out the sides of the firebox. That is as much exhaust flexible gas as the boiler can take. Then invest in a radiant burner, but don't get one with a bigger jet than the biggest camping stove you can use. The radiant is more efficient, but not worth the cost in the saving of gas.... but it can be nicer and easier to manage.
5. I have made dozens of ceramic and other burners. Tell me your flue tube number and bore size the height and diameter of your firebox, and I'll suggest the biggest burner and jet you can use.
6. Tell me the bore stroke and speed of engine, and pressure for the safety relief of the boiler and I'll work out the maximum steam demand.
7. All the sums are in books, or interweb if you want to do it yourself.

Enjoy steaming!
K2

 

[ajoeiam]

Hi Carlos,
The photos in this thread look good. I have been making boilers and burners for many years off and on. Silver solder melts typicallying at 630C and above depending on the alloy. That is a dull red heat. When soldering a boiler I use 2 or 3 blow-lamps, and the boiler is 3/4 buried in sand or enclosed in a fire-brick oven. I doubt you camping stove could melt a joint if you have water in the boiler. Where is the water level gauge?
Properly designed joints will be at least as strong as the copper, so should never fail in a wet boiler..... except if in regions where the water cannot reach... Many loco boilers fail at flue tube joints high in the firebox, when at full pressure and the water is allowed to drop below the top of the firebox.
In your vertical boiler, the top of the firebox is below the water so cannot overheat.
A couple of points:

1. 
   
2. All the sums are in books, or interweb if you want to do it yourself.

Enjoy steaming!
K2

Would you care to share even a list of those resources (links would be easier but I'm not picky!!)

 

[Steamchick]

Hi AJ:
Some reference material I use:

• Model Boilers and Boilermaking: K.N.Harris. (The best book I have on the subject! - Makes "boiler Engineering" easier.).
• The examination and testing of minature steam boilers: Southern Federatiuon of Model Steam societies. But your local society will also have some document telling you their minimum requirement for the code that must be followed before you can run within their rules and insurance.
• Safety of Copper boilers: by Kozo Hiraoka: and ASME "Boiler and Pressure vessel code". He is a genius at making the ASME codes and design of boilers easy to follow. See also his Safety Valve article in "Live steam and outdoor railroading" - worth buying the back-issues for these 2 articles.

Regarding the latter 2: refer to your National location for the relevent codes as the codes for UK, Europe, Australia, USA, S. Africa, etc. all vary. I am in the UK and my model club - who certify my boilers use UK codes, but I design to "worst case" of UK and US codes. - for safety. US code limits Copper body Silver Soldered boilers to 100psi for sound Engineering principles. - I don't argue with that when designing a boiler, or re-instating from an unknown history.
Remember, working outside of National codes and practices is entirely at your own risk - same as driving a car without correct insurance. So no-one should post anything on the web suggesting you by-pass codes, as that is illegal in most countries. (Hence the nature of my advice).
I'm sure you understand.
Incidentally, despite what you may see as "common practice", the Safety Valve is just that. Something that operates to keep you safe. Is is bad practice to run a boiler with the safety valve operating continuously: This just shows "bad management" of the fire. The safety valve is intended to operate a few % over the NORMAL WORKING PRESSURE: (While you may not crash and hurt anyone, speed cops love to book people for being "a few % over the limit"). So please operate your boiler upto and not exceeding a limit marked on the gauge that is below the safety valve operating pressure, (I.E. NWP). But check the natural operation of the safety valve against your gauge upon first firing EVERY TIME you use the boiler. Any problems, shut down fully at the safety valve operating pressure and fix the problem BEFORE you continue steaming. - It only makes sense. Even in your own Garage!
Enjoy (safe) steaming.
K2

 

[Steamchick]

Carlos, As you are in Brazil, I have no knowledge of "Codes and Practices" that affect you, but I am sure that with "common sense " and your published plans you can work-out what you need to do.
On Burners: Check the JET SIZE of the burner you are using. That controls everything at "maximum". When the "fire" is bigger that the flue can manage, the flames burn badly, as the back pressure reduces the air-intake for correct combustion. Long before you get a "bad smell" (Unburned gas in the exhaust) you can get CO gas - which is highly toxic - in the exhaust. So PLEASE get a CO Monitor - only a few dollars on the I'net. And if it sounds, TURN OFF the gas and get out into fresh air quickly. CO doesn't just kill, it can simply cause permanent damage to lungs and gives no warning. You simply wake up with a bad head and an oxygen mask on your face, and a worried-looking emergency crew!
What I use for Butane for a 13mm flue is MAX no 5 jet: 20mm flue a no 8 jet, 25mm flue a 12 jet, for a 32 mm flue a max 16 jet. More or less. (less is safer). But a lot depends on the burner position (flames should NOT touch metal), what tubes etc are in the flow to inhibit exhausting, etc. So be prepared to try a burner, if you need more steam try the next size, etc. - That's what most of us do, for all our wisdom!

Incidentally, the gas control valve is likely to be your problem, not the burner. The manufacturer has spent more man-hours than you can imagine with his expert engineers making a burner that is very versatile, down to a safe minimum. But the "cheap" valve (I have one) is the problem. All burners will be "as good as each other" with the valve. - The best valves I have are from GOOD makes of camping stoves. (Camping Gaz, Primus, etc.). If you have a gas cooker, then there is a reason "why" the knob for the lowest setting "clicks" at this point... because below this the burner is "unsafe" and at risk of going out (and gassing you), or of popping-back (when it will burn incorrectly and make LOTS of CO! - even worse!). So if you need to run at LOWER than your current burner can manage, then you need a smaller burner. Domestic Gas cookers have an option of larger or smaller burners for this same reason. Smaller burner, smaller jet, easier control. Big burner = Bigger heating ability, but the lowest setting is still "biggish".

For anyone who worries why I "bang-on" about CO:
A Government health statement: As CO levels increase and remain above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea. At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.
So please use a CO warning alarm.
And if you ponder why I don't mention CO2...
Concentrations of more than 10% carbon dioxide may cause convulsions, coma, and death [1, 15]. CO2 levels of more than 30% act rapidly leading to loss of consciousness in seconds. It is relatively much harder to get to such concentrations with a small burner in your garage.
Safe steaming!
K2

 

[Richard Hed]

Hi AJ:
Some reference material I use:

• Model Boilers and Boilermaking: K.N.Harris. (The best book I have on the subject! - Makes "boiler Engineering" easier.).
• The examination and testing of minature steam boilers: Southern Federatiuon of Model Steam societies. But your local society will also have some document telling you their minimum requirement for the code that must be followed before you can run within their rules and insurance.
• Safety of Copper boilers: by Kozo Hiraoka: and ASME "Boiler and Pressure vessel code". He is a genius at making the ASME codes and design of boilers easy to follow. See also his Safety Valve article in "Live steam and outdoor railroading" - worth buying the back-issues for these 2 articles.

Regarding the latter 2: refer to your National location for the relevent codes as the codes for UK, Europe, Australia, USA, S. Africa, etc. all vary. I am in the UK and my model club - who certify my boilers use UK codes, but I design to "worst case" of UK and US codes. - for safety. US code limits Copper body Silver Soldered boilers to 100psi for sound Engineering principles. - I don't argue with that when designing a boiler, or re-instating from an unknown history.
Remember, working outside of National codes and practices is entirely at your own risk - same as driving a car without correct insurance. So no-one should post anything on the web suggesting you by-pass codes, as that is illegal in most countries. (Hence the nature of my advice).
I'm sure you understand.
Incidentally, despite what you may see as "common practice", the Safety Valve is just that. Something that operates to keep you safe. Is is bad practice to run a boiler with the safety valve operating continuously: This just shows "bad management" of the fire. The safety valve is intended to operate a few % over the NORMAL WORKING PRESSURE: (While you may not crash and hurt anyone, speed cops love to book people for being "a few % over the limit"). So please operate your boiler upto and not exceeding a limit marked on the gauge that is below the safety valve operating pressure, (I.E. NWP). But check the natural operation of the safety valve against your gauge upon first firing EVERY TIME you use the boiler. Any problems, shut down fully at the safety valve operating pressure and fix the problem BEFORE you continue steaming. - It only makes sense. Even in your own Garage!
Enjoy (safe) steaming.
K2

Thank you for that. When I make a serious boiler, it will have at least TWO safety valves. ONe for the proper amount of steam and one for about 5% above that.

 

[Steamchick]

Hi Richard, Being in the US of A (I think that is where you find Seattle? - I spent 6 hours in the airport there awaiting my connection between Hawaii and Amsterdam many years ago...) you will find the regs stipulate that the real SAFETY valve must manage all the steam at full burner (and blower if fitted) within 6% of the NORMAL WORKING PRESSURE: The NWP is not to be controlled by a "blow-off valve, but by sensible driving of the boiler in harmony with engine load... Making a "pop" type valve that works reliably to open above NWP and not allow the pressure to rise more than 6% over NWP is a bit of a task, and may take some tuning. But Kozo Hiraoka has written an excellent article on Safety Valves in Live steam and outdoor railroading magazine: I strongly advise you buy a back copy and study his designs. They are well proven I understand, based on many earlier designs but shown in many sizes in the article. Also, I seem to remember he explains how to size the valves and determine the set pressures, and how to set them, for the ASME codes.
When it comes to "Safety" I recommend using the codes, as it saves re-inventing the wheel and getting it "off-round"... And every boiler above atmospheric pressure should be taken seriously, to the point of scrapping boilers that are not fit for purpose... Have you ever spilled boiled water from a kettle on your hand and felt the pain? Multiply that by hundreds for the pain from steam venting onto flesh.
Take care mon ami,
K2

 

[Richard Hed]

Hi Richard, Being in the US of A (I think that is where you find Seattle? - I spent 6 hours in the airport there awaiting my connection between Hawaii and Amsterdam many years ago...) you will find the regs stipulate that the real SAFETY valve must manage all the steam at full burner (and blower if fitted) within 6% of the NORMAL WORKING PRESSURE: The NWP is not to be controlled by a "blow-off valve, but by sensible driving of the boiler in harmony with engine load... Making a "pop" type valve that works reliably to open above NWP and not allow the pressure to rise more than 6% over NWP is a bit of a task, and may take some tuning. But Kozo Hiraoka has written an excellent article on Safety Valves in Live steam and outdoor railroading magazine: I strongly advise you buy a back copy and study his designs. They are well proven I understand, based on many earlier designs but shown in many sizes in the article. Also, I seem to remember he explains how to size the valves and determine the set pressures, and how to set them, for the ASME codes.
When it comes to "Safety" I recommend using the codes, as it saves re-inventing the wheel and getting it "off-round"... And every boiler above atmospheric pressure should be taken seriously, to the point of scrapping boilers that are not fit for purpose... Have you ever spilled boiled water from a kettle on your hand and felt the pain? Multiply that by hundreds for the pain from steam venting onto flesh.
Take care mon ami,
K2

Under NO circumstances would I trust steam under pressure. I know that after two centuries of steam, all the details have been workt out properly0--even so, I don't trust anything that could kill me. MY second valve is in the nature of a back-up redundant system. Valves stick, bad things happen to goo people and sh)te happens. Redundancy is not a BAD thing, it is extra safety. That is a goo thing.

 

[Steamchick]

OK Richard. I trust you to be a sensible guy. Most of my message is for the benefit of readers that simply "do not know". New people to the subject, 'n all. My simple message: it is common sense to apply the regs and codes of practice as a minimum. Don't ignore them - they are for everyone's safety.
Of course additional safety items are good, providing there is no conflict of operation related to the items that are to meet the regs. and codes.
Stay safe, live long, stay happy.
K2

 

[Steamchick]

Hi Richard, I trust you would always give me your most sensible advice, just the same. I have read a lot by you and respect your knowledge and experience.
Sorry, if I had caused any offence.
K2

 

[Richard Hed]

Hi Richard, I trust you would always give me your most sensible advice, just the same. I have read a lot by you and respect your knowledge and experience.
Sorry, if I had caused any offence.
K2

Of course not any offense. I'm and adult. Anything I make always goes by the code ++

 

[chrsbrbnk]

Looping back to the CO thing I had a CO leak from my furnace a couple years back of about 20 -35 ppm levels that don't show on the household alarms and digital detectors but we were having a rash of headaches and fine motor skills were affected like our archery scores dropped. anyway the point is that CO does not readily come back out of the blood it takes days. I suspect the gov. recommended levels are way to high for any prolonged exposure. might be reasonable to think of running a boiler on the kitchen with the stove vent sucking or similar type of venting. sorry about the rant chris

 

[Steamchick]

I learned about CO and headaches when I had old cars - and the Kids were getting horrible headaches and drowsy in the back seat on long runs. The seals on the tailgate were leaking and sucking exhaust fumes into the back (3rd. row) seat zone. It was on a very long run - maybe 3 hours plus - that my wife and I got bad heads when I realised what was happening... After that we used to keep a window just cracked open to suck more ventilation through - 'till the car was changed!
But I like having the CO alarm in my Garage for when I have a couple of blow-lamps blasting away on a copper boiler for silver soldering!
K2

 

[Richard Hed]

I learned about CO and headaches when I had old cars - and the Kids were getting horrible headaches and drowsy in the back seat on long runs. The seals on the tailgate were leaking and sucking exhaust fumes into the back (3rd. row) seat zone. It was on a very long run - maybe 3 hours plus - that my wife and I got bad heads when I realised what was happening... After that we used to keep a window just cracked open to suck more ventilation through - 'till the car was changed!
But I like having the CO alarm in my Garage for when I have a couple of blow-lamps blasting away on a copper boiler for silver soldering!
K2

Altho' CO itself is odorless, the other carbon related unburnt fumes should always be a clue to the poison presence.

 

[Steamchick]

Hi Richard, Back in the 1970s and 80s there was so much pollution around the brain switched OFF to most of it... cars were simply "smelly things". I didn't used to smell exhaust much unless from a bad diesel truck. But nowadays, my 1979 Moto Guzzi absolutely stinks! The garage even stinks the following morning after I have been out and put it away the day before. Though I don't remember it stinking 20 years ago. Car exhausts are now below 1% of the CO that they used to produce - buts a lot more around now - except for COVID restrictions on travel "except when really necessary". And Hydrocarbons, etc. are all similarly lowered. You won't smell the CO from the boiler burner - and it probably won't have much else except H2O and CO2... so won't smell noticeably anyway. As the brain turns OFF progressively increasing smells, it only makes you aware of "new" smells..., then even a slowly worsening atmosphere in the garage won't be detectable. But the CO detector will shout when it gets to a certain level. For less than £10 on the intershop I thought it worth shouting about. - Just so you all don't go and die on me and I'll have no-one to moan to...
K2

 

[Steamchick]

Hi Carlos, We crazy people have digressed from your request for "the best" burner for your boiler.

• Did you get the information you need?
• How are you progressing?
• Can we give you any more advice?

If you tell us the size of firebox - where a ceramic burner could fit - maybe we can make some plans for you to make a burner? - or I could make a burner for you? (I sell them on e#@y). But I would also need to know how big is the passage for gas to pass through the boiler. Is you existing burner OK when turned onto FULL GAS setting? = Does it give you enough steam? - Do flames leak out anywhere?
Cheers!
K2

 

[Richard Hed]

Hi Richard, Back in the 1970s and 80s there was so much pollution around the brain switched OFF to most of it... cars were simply "smelly things". I didn't used to smell exhaust much unless from a bad diesel truck. But nowadays, my 1979 Moto Guzzi absolutely stinks! The garage even stinks the following morning after I have been out and put it away the day before. Though I don't remember it stinking 20 years ago. Car exhausts are now below 1% of the CO that they used to produce - buts a lot more around now - except for COVID restrictions on travel "except when really necessary". And Hydrocarbons, etc. are all similarly lowered. You won't smell the CO from the boiler burner - and it probably won't have much else except H2O and CO2... so won't smell noticeably anyway. As the brain turns OFF progressively increasing smells, it only makes you aware of "new" smells..., then even a slowly worsening atmosphere in the garage won't be detectable. But the CO detector will shout when it gets to a certain level. For less than £10 on the intershop I thought it worth shouting about. - Just so you all don't go and die on me and I'll have no-one to moan to...
K2

Yes, of course, I'm only talking about cars -- they don't burn completely cleanly.[/QUOTE][/QUOTE]