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[1967Brutus]

 I favor filling up with a bleed  off line extended with silicone tube to let the gas escaping outside the boat. 

Thanks for the videos. They are clear and enlightening.

Not letting gas escape INTO the boat, in itself is clear, but... I have so far never seen the need for letting gas bleed off during filling?

I like those snap-on couplings... who sells them? Haven't found them yet.

[rhavrane]

Bonjour,
These ones ?
  - http://fr.rs-online.com/web/p/coupleurs-rapides/6671784/?sra=pstk 
  - http://fr.rs-online.com/web/p/coupleurs-rapides/6671778/?sra=pstk
 

[KBIO]

Hello !
Filling up a gas tank with no bleed off is like filling up blind. You never know if it's full or not , above all with the connections supplied . A bleed off with a plunger inside the tank at about 15/20 mm from the top is a clear indication of the tank being full when the liquide spits outside.... the boat !   and it leaves a void space for safety .

I get those push/pull connections for a fair price ,compared to what is proposed in some other places , in Germany:[size=78%]
https://www.bengs-modellbau.de/en/Quick-coupling-Nw-2.7/7021
[/size](you have plenty informations and suppliers all over the world , here: https://modelismenavalvapeur.forumactif.com/ )[size=78%]


Whatever I built , I keep my standards to :
-  6,75 mm for steam and 5,50 for gas. I keep BA in BA as I have the tap & die for it , but as I am always doing tests , I am swapping engines or boilers and standard threads make the thing easy.
I'm gone for a few days ! Have fun and "Steam up"!


[/size]

[1967Brutus]

Thanksfor the info, guys!

Feel a bit silly, since I have bought from Bengts before, the grafisil balls for my safety valve repair... Guess I did not look properly, huh? Duh...

[1967Brutus]

Filling up a gas tank with no bleed off is like filling up blind. You never know if it's full or not , above all with the connections supplied . A bleed off with a plunger inside the tank at about 15/20 mm from the top is a clear indication of the tank being full when the liquide spits outside.... the boat !   and it leaves a void space for safety .

Makes sense... My tank is removable, I weigh, so I know what is inside...

Raphaël showed a gas tank with a level glass... I guess that would be my preference in case weighing is not an option, but your solution works as well.

[KBIO]

For a while I used to build gas tank with glass gauge . But I quickly realized that it not very handy to see them when inside the boat and that the tube glass is very fragile .
They end up cracking and leaking (always at the bad time) and the O'ring getting old ends up by leaking.
I then did some with a polycarbonate window , which is a lot stronger and safer , but still , it is difficult to check the level when inside the boat.
I must admit that , even if I don't use them anymore , it is lovely to have it.
Just do what you like, as long as you like it , that's make the life brighter and the steamer happy !
 

[1967Brutus]

Just do what you like, as long as you like it , that's make the life brighter and the steamer happy !
 

It's not a matter of choice... I only have ONE gastank, and it's not fixed in the boat

[KNO3]

Hermann Echtdampf sells a full set for converting Regner gas tanks to quick coupling, including the valve and pipe for refill from a commercial gas canister:
https://www.echtdampfwelt.de/gaseinfullsystem.html

The parts can be bought separately as well:
https://www.echtdampfwelt.de/echtdampfshop/gasarmaturen.html

[DBS88]

Out of curiosity I have now added a pressure gauge to the refillable gas tank so that we can see the pressure in the tank at the start and also whilst the burner is running. The guage is connected to the valve that supplies gas in the gas phase. In the video, the burner is running completely from the liquid phase valve. My workshop temperature is about 20C, the pressure shown at the start is 45psi or 3Bar. The pressure remains constant through out the test, after a couple of minutes gas valve is opened further and the burner runs near to its maximum with a 0.5 gas jet, the pressure remains at 45psi or 3 Bar, the gas tank does not get cold, no condensation forms, and no icing on any of the pipework. The flame is a good steady flame.
https://youtu.be/4haodDkh0M8?si=yuy8hr9RpY3H7tMf


We now know that the pressure in the system is 45psi or 3 Bar which is higher than the 2 Bar that I have seen other video's of liquid phase gas being used.
The figure of 3 Bar or 45 PSI in my tank at 20C was worrying me, since other videos show 2 Bar, I wondered if my gauge was not working properly? I did some further research and it appears from this chart that 3 Bar is about right.
I hope this further information is useful to your project

[rhavrane]

Bonjour,
For fun, using the usual gaseous phase with a large burner : https://youtube.com/shorts/RPYHMExjdIo

[1967Brutus]

Out of curiosity I have now added a pressure gauge to the refillable gas tank so that we can see the pressure in the tank at the start and also whilst the burner is running. The guage is connected to the valve that supplies gas in the gas phase. In the video, the burner is running completely from the liquid phase valve. My workshop temperature is about 20C, the pressure shown at the start is 45psi or 3Bar. The pressure remains constant through out the test, after a couple of minutes gas valve is opened further and the burner runs near to its maximum with a 0.5 gas jet, the pressure remains at 45psi or 3 Bar, the gas tank does not get cold, no condensation forms, and no icing on any of the pipework. The flame is a good steady flame.
https://youtu.be/4haodDkh0M8?si=yuy8hr9RpY3H7tMf


We now know that the pressure in the system is 45psi or 3 Bar which is higher than the 2 Bar that I have seen other video's of liquid phase gas being used.
The figure of 3 Bar or 45 PSI in my tank at 20C was worrying me, since other videos show 2 Bar, I wondered if my gauge was not working properly? I did some further research and it appears from this chart that 3 Bar is about right.
I hope this further information is useful to your project

Too bad the noise of the burner near completely drowns out your voice and makes your comments unintelligeble, but absolutely a very useful and inspiring video.

the 2 bar might be the result of using a filling bottle that also has been feeding a burner in the gaseous phase some previous occasion, and the propane content of the mix in that bottle having lowered a bit.

[rhavrane]

Bonjour,
We are supposed to use a pressure of about 800g / 10 - 15 PSI to the burner and a gas regulator needs a gaseous phase, this means that, in a liquid phase mount, these parameters should be taken in account,
I say that because for me, a gas regulator is a securing accessory as it is not mandatory in the practice of model boats I mean !

 

[KBIO]

Helo !



A very accurate observation, as the propane %tage decreases more rapidly. But if you look at the chart above, a difference of 5°C justifies the pressure difference.
Many burner tests are carried out at room temperature, and in a workshop, the temperature is more often 15°C than 20°C, especially in winter.
This means that DS88's reasoning is correct, given the chart.


Below is a graph I propose on my forum , showing how propane behaves during burning and why the pressure in the tank drops.
Note that when the tank level is at the middle , there is 25% Propane for 75% Butane .The propane would only propel the mixture, the two calorific values being more or less the same.

[1967Brutus]

Bonjour,
We are supposed to use a pressure of about 800g / 10 - 15 PSI to the burner and a gas regulator needs a gaseous phase, this means that, in a liquid phase mount, these parameters should be taken in account,
I say that because for me, a gas regulator is a securing accessory as it is not mandatory in the practice of model boats I mean !

Not sure if I understand this post properly...
I understand what you mean by a "securing accesory".

I mean, how does it improve safety?

I agree on the constant pressure, but in my opinion, "liquid phase feed" allready provides a significant improvement on the stability of the fuel pressure.

[rhavrane]

Bonjour,
Sorry, my French is better than my English to give my opinion, would it be because I am French  ?

What I wanted to say is that for me I specify, the gas regulator is a very useful accessory in terms of safety.

In fact, in the event of the boat being blocked unexpectedly in the middle of the lake, as has already happened to me, a regulator stops the pressure increase and the consumption of steam, which leaves much more time to carry out a rescue and avoids any risk of possible deterioration of the boiler.
It is not mandatory and I feel much more safe with one on my steam plants.

My friend Google, I like using when I have a doubt or a lack of vocabulary translated "sécurisant" by "secure" because I thought that "comfortable" was not appropriate to translate my opinion.

Counter example, for the "Anton trophy", we operate at 8 bar (+/-120 PSI) max and there, no regulation, all the heat power is needed and our lonely safety accessory is the RC safety gas valve : https://youtu.be/IzHLYp4lXtM  (The winner, "Ky" as a more efficient boiler than mine as we have the same speed machines https://youtu.be/pxjvgliqmuI )

[1967Brutus]

Thanks for the explanation. Languages and translations can be tricky at times.

[1967Brutus]

Despite being an engineer, I do not know those numbers by heart, so I had to look them up...
Not being pedantic, I just found information differing from yours.
According to my AI buddy on the web, Propane and Butane start decomposing around about 480 deg C, literal statement was:  "at the auto-ignition point, 480 degrees".
According to Wiki, the auto-ignition temperature is around 280 degrees, and that usually is the temperature where molecules become unstable, because they show a strong tendency to react with other molecules without external provocation. So now we have three values, appr 280 deg, appr 480 deg, and "above 700 deg in presence of a catalyst.
Given that the gas is pressurized throughout the entire fuel circuit until either nozzle or control valve, whichever of the values turns out correct, that critical temperature could be significantly lower.
Personally, I still think the chances of dirt being formed in the evaporator being higher than the dirt being carried from the bottle to the tank to the burner, and given that it happens also on vapourfeed installations, I would not be surprised if the dirt is being formed at the tip of the nozzle even...

On the bolded, I have a question: those that experience gas blockages in vapour fed installations, how intensively do they operate their equipment, and what consumption rates are we talking about?

Because here is why I can't grasp the concept of there being dirt in the gas:
-IF the blockages are being caused by dirt, it would be fair to assume, this dirt has certain dimensions, no? The gas as we buy it being filtered and all should suggest a certain max possible particle size.
-If above assumption is valid, it would also be fair to assume, that "trouble-interval" would be depending on nozzle size, no? A smaller nozzle would block sooner than a wider nozzle, if particles are the reason, because the smaller particles would pass a wider nozzle unhindered, but might get stuck in a smaller nozzle...

Reason I am pushing this subject a little, is that I an fairly certain that not many people run their set 80+ hours in a single year. Most people I talk to, speak of maybe 5 hours per year, if that...
But that is the kind of runtimes I am getting. I have a relatively small burner (max about 90 grammes per hour, average 60), meaning my burner has seen roughly 5 kilos of fuel and all of it throught that one single tiny nozzle. If dirt would be a problem, I run no filter and my burner has a relatively small nozzle, I would expect to have seen trouble allready...

I have anyway a very hard time imagining how dirt particles, once on the bottom of the fuel tank, would be carried away by the vapours above the liquid surface. I just don't see the mechanism... I could see that happening in liquid feed installations, but not in vapour feed systems.

Again, if this comes across as pedantic, I apologize once more, that really is not my intention. I see things that do not add up, and being a bit autistic, that does not go down easy.

I am coming back to this, for reason that I opened my gastank today to check the possibility to install a riser tube under the gasvalve (which is no problem).

When doing so, I also measured the exact volume of the tank by filling it with tapwater (measured volume 135 ml) and I checked with a light before filling if there was any debris inside.

I emptied the tank via a coffee filter to see if there would be any debris coming out with the water. I found none. Flushed it 3 times with destilled water, same procedure, there was absolutely NO debris in the tank whatsoever.

About 5 kilogrammes of gas have been evaporated in that tank, if there would have been ANY dirt in the gasbottles that I use for filling (I have used 3 different brands, the bulk of it Rothenberger, but also a few no-brand generic bottles) it would have collected in the tank.

Therefore, I absolutely do not believe in dirt coming from those bottles, and any dirt formed, therefore HAS to originate from overheating/decomposing in the evaporator.

I am currently modifying, using a temporary coil of 2 mm ID (3 mm OD) because I do not have any other suitable material.
Gas tank has its riser pipe, and appears to be gas-tight. So far, so good.
Coil will be experimental-only-aesthetics-later...

[1967Brutus]

Well...

I think I overestimated the Regner gasvalve's abilities...
I have a HUGE fire now, and the regner valve barely controls it... Even with the engine full ahead, and the gas regulating valve at minimum, burner pressure was in no time over 2 bar (control setpoint 1,5 bar).

Now it is very possible that I accidentally opened the pilot regulating valve.

Anyway, with a bit of care, it IS possible to fire up without a vapour circuit, and despite the humongous fire, and the heating deactivated, the fuel tank picked up temperature fairly quickly to 28 degrees C.

So THAT part of the game works.

A second, slightly less nervous (me) run, allowed me to pay a bit more attention, and this revealed that the controlvalve DOES control, it simply needs a bit of readjustment.

Apart from that, it worked fabulous! The tank remained constant in temperature without heating, the fuel pressure, judging by the virtually total lack of correcting action by the pressure control was absolutely constant from the very beginning till the last 30 seconds.
When fuel ran out, in about 10 seconds the burner controller went from about 20% to 100%, the flame reducing, and about 10 seconds later the flame went out, just like that.

Video:

First run with experimental liquid gas feed

[1967Brutus]

I remembered, that when I first received the valve, and used it with an unheated gastank, about a year and a half ago, I was not impressed with maximum fire, so I shifted the lever a bit over the control spindle.

Back then I was running a cold tank and thus lower fuel pressure.

I restored original calibration of the controlvalve, and now it simply works. I had to set a pilot fire adjustment to prevent the burner from extinguishing, but other than that it now works like a charm.
Rocksteady pressure control, and from full tank to empty, the burner position does not change if the steamthrottle is not moved.

I am very pleased.

Of course, I need to re-do the entire system, because it works in the test-conditions (indoor, no wind) but it looks ugly as heck.
I have a few ideas for that, but if I can do that, remains to be seen.

The start is relatively simple: Set RC valve to manual, and set it to full open, liquid valve closed. Hold a pilot fire at the funnel, and very carefully open the liquidvalve until the fire catches. Manually keep the fire a bit low. Within about 15 seconds, the RC valve can be closed. If fire responds, the liquid valve can be carefully opened further. Raise steam on a tempered fire. Onc pressure is in range, set RC valve to auto.

https://www.youtube.com/watch?v=TZ4jjKwckxw

[1967Brutus]

Rearranged the evaporator coil to make use of heat transfer through metal-to-metal contact instead of the hot gasses.
Reasons for doing, first of all, the first experimental set-up really looked like crap, second, the coil was located OVER the flue gas outlet.
A gust of wind would mean that the hot outflow would be pushed aside, not only robbing the coil of its heatsource, but maybe even actively cooling it. Dangerous!


The coil now being located lower, and in direct metallic contact with a guaranteed hot metal conduct should ensure a more stable heat supply, of still an acceptably low intensity.

How it looks now:



To me, this is aesthetically acceptable.

[DBS88]

Well done and thank you for sharing your work with us, we can all learn from what you have achieved.

[rhavrane]

Bonjour,
Nice job indeed to my opinion, furthermore it fully justifies the French expression "Usine à gaz"     

[1967Brutus]

About 5 kilogrammes of gas have been evaporated in that tank, if there would have been ANY dirt in the gasbottles that I use for filling (I have used 3 different brands, the bulk of it Rothenberger, but also a few no-brand generic bottles) it would have collected in the tank.

Therefore, I absolutely do not believe in dirt coming from those bottles, and any dirt formed, therefore HAS to originate from overheating/decomposing in the evaporator.

Yeah, right! Me and my big mouth... Spent about an hour messing about and swearing, not understanding why the darn thing would not light.
Found the nozzle blocked.


Does only confirm my conviction that there is no dirt in the gas though, because how else would I be able to burn 5 kilo of gas without any problems, have a squeaky clean fuel tank, but still within 2 runs after changing to liquid fuel feed encounter a blocked nozzle?

My best guess is that I soldered the fuel lines with resin core tin, and the fuel now being liquid in the line, dissolves the resin.
Anyway, after U-son cleaning, the thing ran again, and the new evaporator is easy to use.
I lighted the burner with everything cold, which is doable if being done careful, but I think the new standard will be to heat the funnel for 10~20 seconds with one of those tiny burners (I belive they are used to make "crème brulé" or something, anyway, barely bigger than a cigarette lighter and a nice little flame. Heat the evaporator, open the fuel and light the burner. A bit of assist at the evaporator for the first 10 or 20 seconds, and things should work all on their own from there.

And they do:

https://www.youtube.com/watch?v=VbxQ-J2g41M

[1967Brutus]

Well done and thank you for sharing your work with us, we can all learn from what you have achieved.

Thanks! It seems to work really well, but I have to still get used a bit to the slightly different behaviour at start-up and initial raising steam.

But the constant, and much higher fuel pressure is a real blessing. The fact that the RX battery load has reduced by about 65% is marvellous (and was the primary goal), but the stability of the system is really amazing. So much so, that there literally is ZERO indication of fuel remains decreasing, AT ALL...
It just goes and goes, and all of a sudden, simply the burner control goes to full within a few seconds and that's it...

In the old situation, I saw a fairly constant steam pressure, but over the duration of the run a gradual increase of the burner control, due to the dropping fuel pressure. That gave me a crude indication of fuel remaining. Now I REALLY have to fill the tank to a prescribed amount and use the timer, or I am screwed.

Oh, well, there's a downside to everything I guess... :p

[1967Brutus]

Bonjour,
Nice job indeed to my opinion, furthermore it fully justifies the French expression "Usine à gaz" 

I had to look that one up, but.... yes... it does, doesn't it?

Yet, while by now over the course of a year the internals of the boat resemble a plate of spaghetti, the liquid feed system actually is extremely simple, and way easier to use than I expected...