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[SimonCornes]

Simple question- how do you do it? I have a Cheddar gas tank with a filling fixture and a valve. I have a Coleman’s tin of propane/butane mix with an adaptor. So, with the tank out of the boat, do I fill the tank with the Coleman’s cylinder pointing up, down or horizontally and how do I know when it’s full??
I have the same issue when filing has cooking hob lighters but at least mine has a window in the side so I know how much is in!!
Many thanks
Simon

[rhavrane]

Bonjour Simon,
He is the accessory you need for a Cheddar tank : https://youtu.be/eez9ACLowcQ

When a gas tank has a purge valve like the JMC example, it's easy to know when it's full, with the Cheddar system you have to guess it when you see liquid gas coming out of the filling port... Not obvious I agree.

[SimonCornes]

Oh Raphael, if only I spoke French!!    But I can see that the JMC tank is an improvement on the Cheddar tank because of the purge valve and sight glass to visually see the contents. I’m not sure if he suggested a piece of silicon tube on the Cheddar adaptor to prevent gas escaping before the tank was full?? Bit I can see that he filled it holding the gas canister pointing vertically downwards.

[DocMartin]

Simon:
Raphael consistently posts very helpful videos (en Francais).  You can take advantage of these videos by selecting the Subtitle function from the Settings icon on the YouTube page just below the posted video (looks like a six toothed gear).  When you click on Subtitles, select Auto-Translate and then choose English.  This will show English subtitles on the page.  The translations are never perfect but the salient information can be garnered from each video.  Give it a try.

DM

[Bunkerbarge]

Fill the tank upright, preferably sat on a hard surface.  Open the outlet valve just a very small amount, you should only just be able to hear the hiss as the gas escapes.  Push the connector from the disposable tank onto the Ronson valve, firmly to ensure it isn't leaking at the Ronson valve.  Fill the tank until you get liquid spitting from the outlet valve.  Stop filling and leave the outlet valve open for a second to ensure there is a gas space at the top of the liquid.  Then shut the outlet valve and refit the tank.


It is also worth weighing the tank when it is totally vented and when it is completely full.  That way you can always check whenever convenient by weighing to see how much gas you have in the tank.  Experience will guide you as regards how long you expect it to last.

[SimonCornes]

Simon:
Raphael consistently posts very helpful videos (en Francais).  You can take advantage of these videos by selecting the Subtitle function from the Settings icon on the YouTube page just below the posted video (looks like a six toothed gear).  When you click on Subtitles, select Auto-Translate and then choose English.  This will show English subtitles on the page.  The translations are never perfect but the salient information can be garnered from each video.  Give it a try.

DM

Thank you - I’ll have a go at that!!

[SimonCornes]

Fill the tank upright, preferably sat on a hard surface.  Open the outlet valve just a very small amount, you should only just be able to hear the hiss as the gas escapes.  Push the connector from the disposable tank onto the Ronson valve, firmly to ensure it isn't leaking at the Ronson valve.  Fill the tank until you get liquid spitting from the outlet valve.  Stop filling and leave the outlet valve open for a second to ensure there is a gas space at the top of the liquid.  Then shut the outlet valve and refit the tank.


It is also worth weighing the tank when it is totally vented and when it is completely full.  That way you can always check whenever convenient by weighing to see how much gas you have in the tank.  Experience will guide you as regards how long you expect it to last.

Thank you BB. This morning I tried filling the tank then fired up the boiler for the first time. I think it might have run for 3 or 4 minutes and didn’t get up to 45psi before it went quiet and I’d obviously run out of gas. I weighed the tank and then had another go at filling it but I didn’t open the outlet, I just used the adaptor 3 or 4 times and stopped only when I was getting liquid gas running over the tank but I could hear the liquid sloshing around inside. Bear in mind this is the first time I’ve ever run a steam plant. The first thing I noticed was the boiler singing like a kettle and I understand that means I need to move the flame holder in a bit and until it stops? Couldn’t do that then because everything to hot so i ignored the noise! I also noticed some small water leaks from the pressure gauge banjo and water level sight glass top fitting so tightened both up a bit and I think they might be okay now I also had a bit of leakage around the safety valve but, again, too hot to tighten more. At about 43psi the valve lifted and water and steam shot up the extension pipe and after about 30 seconds with nothing changing and steam and boiling water shooting upwards I chickened out and closed the gas tap. The system is fitted with a Cheddar
Electronic Gas Valve but I have no instructions for it. I assume you have to turn the pot to reduce the temperature at which it operates to just below the safety valve lifts so maybe 42psi ?
The screw that holds the flame holder is loose so i was able to push it in a bit so I’m thinking of firing it up again tomorrow morning to see if the constant whistle stops. If it doesn’t I assume I have to shut down again, let it cool and move the holder in a bit more? All very trial and error. I did use the steam in the boiler to run the Puffin twin the first time and to discover that I needed to reverse the throttle channel and to prove to myself that it basically works!
Given that I bought the boat with a theoretically operational plant then I’m a bit surprised that the flame holder was loose but I would also think that the automatic gas valve would previously have been set up so that no adjustment is required now? Any advice would be gratefully accepted!
Simon

[Bunkerbarge]

Simon, If you don't open the gas tank outlet valve, albeit very slightly, as the tank fills with liquid the displaced gas has nowhere else to go but back into the disposable tank.  This disrupts the flow of liquid into the tank and makes filling very difficult.  That is precisely why you were getting spitting at the filling valve, which is a waste, it was not because the tank was full but was because the gas is trying to get back into the disposable tank.  If you don't very slightly open the valve you will find filling the tank difficult and misleading and sometimes not actually possible.


When you say flame holder I take it you mean the nozzle holder?  A good starting position is with the tip of the nozzle holder in the centre of the air hole.  That is usually a good enough location.  You can adjust the position with the burner operating, just loosen the screw slightly and tap the nozzle backwards and forwards gently with a metal object.  You will hear the change in the flame and should see a different colour looking down the flue.  Not too close.  You want a blue flame usually with a good bit of noise.  You won't be far away from the central position.


To set the EGV, raise the pressure slowly by controlling the burner with the gas valve on the tank, then, when it gets to the required or working pressure, 45 psi in this case, then adjust the potentiometer screw until you see the gas servo operate.  Then open the tank valve fully and run the engine to use some steam.  You will find there is around a 5 to 10 psi delay in the servo operating in either direction so you might need one or two very fine tweeks of the potentiometer to get it just where you want it.  First time of use I would simply let the pressure rise and see at what level the servo operates.  Unless of course it doesn't in which case you will have to adjust accordingly.


Both the nozzle position and the EGV setting are operator set variables and both should be checked even if the plant is sold as operational.

[SimonCornes]

Thank you so much for that - I will print off a hard copy for future reference! The screw in the flame holder is already loose and the nozzle is quite a tight fit. I suppose this is where it’s good to set up the plant outside the boat!! I will persevere until I get there!! Thanks again.

[Bunkerbarge]

Just to give you an idea with a burner type that can be safely run outside the boiler:


The pictures show the nozzle in its normally best position.  Then the three flame pictures show a weak yellow flame when the nozzle holder is pushed in too far and is blocking off the airway, and a too strong a flame with too much air when the flame is pushed away from the ceramic.  This flame tends to be too hot in the centre and too concentrated, rather than a nice even flame across the surface of the ceramic.  Finally the best flame, evenly spread across the ceramic burning at the most efficient to give the best balance between performance and gas consumption.

If the nozzle holder is too tight I would remove it, take the nozzle out, and clean it up with some metal polish or 'T' Cut paint restorer.  If that doesn't help then rub it with some very fine wet and dry abrasive.  When you have finished wash thoroughly in soapy water, rinse and dry before refitting the nozzle.  The nozzle can very easily block with the finest spec of dust so needs careful handling.

[SimonCornes]

Thank you BB. Installed its all a bit tight in the boat, ie not a lot of spanner wielding room, but I'll see what I can do - I think I have a mirror that I can check that gap with. Cheddar suggests 4mm between the face of the nozzle and the far edge of the hole in the holder. It's annoying when you assume that everything will be set up to run perfectly but I guess I'll learn more this way!


Do you also fully open the valve in the gas tank? I guess if you didn't have the EGV that's how you'd control the size of the burner flame so I imagine that when you have the EGV set up properly then that controls the gas flow with the tank valve fully open? It all seems a bit fierce at the moment but, again, I suppose you get used to what is 'normal' ?!!

[SimonCornes]

I’ve just had it going again and I think the gas nozzle is about right now. No steam leaks from any of the boiler fittings and so now I’m playing with the EGV. It could really do with a proper knob on it as I have to remind myself which way to turn it!! I think I’ve got it shutting down but I’m not convinced if it’s opening or closing quickly enough. I’ve stopped now as the water level is down to about half so I’ll refill and try again another day.

[Bunkerbarge]

Simon,  Don't forget the EGV is a little crude in so far as it only switches from 'Full Flame' to 'Pilot Flame' as required.  You can still use the gas tank valve to control the full flame but, if you do, you then have to compensate by adjusting the pilot flame as you don't want that to go so low it might go out.  The pilot flame is adjusted with the little knurled knob on top of the servo operated gas valve, which is basically just a fine by-pass.  I tend to open the gas tank valve fully.

[SimonCornes]

Thank you BB. I see what you mean about a knurled wheel on top of the valve. Someone has put a black paint mark on it. I feel inclined to leave it alone as it hasn’t gone out yet. Wonder if I can find a set of instructions for it? I have a set for the current Clevedon Steam version but it’s not exactly the same.

[KBIO]

Good morning !
A quick experiment of filling a gas tank equivalent of a Cheddar's one , with no bleed off.
Sorry , it's in French but the following explanation will help.
When you transfer liquide gas to an empty tank , exactly like when you fill up a lighter.[size=78%]The  receiving tank is closed = the liquid will flow into the empty tank by the simple difference of gravity.[/size]
Pressure rises in the receiving tank until a gas space of around 20% is left.  You cannot fill up more liquid unless you have a bleed off valve to allow this gas to escape. A transparent silicone hose allows the liquid flowing into the empty tank to be visualized.  The pressure will rise as in the video, but given the ambient temperature: +/- 23°C, the Durit is well below its burst pressure: up to 7 b.
As a general rule, I let the pressure in the boiler build up to 45 psi. I remove the tank, or leave it, and refill with gas before launching the boat.
Remember : the gas is heavier than air , so do not let any gas escaping , leaking , ... inside , and blow it out prior to switch on the burner. The Butane / Propane  is possible when it is  2 to 9% of the total air volume for optimum combustion.


https://youtu.be/kSATuA1FdPw?si=D4EdK_Ei1lM57Gkk


www.youtube.com/@22KBIO

[Bunkerbarge]

I don't think anyone was suggesting that liquid gas would not behave as per the laws of gravity however fully understanding the process that is going on does help us to achieve a much better flow of fluid.  If we do not allow for a small amount of bleed of then the displaced gas must go somewhere and the only place it can go to is up into the filling tank.  You therefore have gas flowing up through the same spaces as fluid is flowing down.  Hardly surprising that this disrupts the flow.


Interestingly in the example in the YouTube clip the liquid fuel is flowing through a sealed connection, therefore reducing the potential for spitting and leakage, and the refillable tank is being filled via a significantly larger bore valve than you find in the Ronson type valve.  When it was first suggested to me by a gas tank supplier that the tank should be bled while filling I was sceptical at first but after a number of tests very quickly became convinced that it is a much better means of filling a refillable gas tank through a Ronson type valve.


As regards filling cigarette lighters, I fully agree, that was always an equally inefficient and hazardous process.


Interestingly when I used to fill up a refillable tank in an enclosed model I have I also filled through a clear silicone tube.  I fitted a vent line to that tank though to take the vent outside the model during filling.  It was interesting to see the slowing down of the liquid flow through the  silicone tube if the vent was closed.


As with all these things I would encourage experimentation to determine what is best for the individual bearing in mind all safety considerations and a good understanding of what is actually happening.  Many years ago I had an interesting conversation with a modeller who had insulated his gas tank in an attempt to prevent it cooling during use.

[rhavrane]

Bonjour,
As you may have noticed it, Kbio and I use what we call "Legris" type connectors. Here are the links if your are interested : 
http://fr.rs-online.com/web/p/coupleurs-rapides/6671784/?sra=pstk 
http://fr.rs-online.com/web/p/coupleurs-rapides/6671778/?sra=pstk
I don't like at all the Regner or Cheddar tanks because I loose a lot of gas during the refill and put fire in one of my boats because of it because I can not remove the gas tank in several of my boats    https://youtu.be/awkPgSYqNM0
Si I decided to modify this tank with a Legris connector and kept the otiginal fill system as purge : https://youtu.be/uBzQW8iq-2o


 

[KBIO]

Many years ago I had an interesting conversation with a modeller who had insulated his gas tank in an attempt to prevent it cooling during use.

Mistake !
When the liquid inside the tank comes to gas , the tank pressure decreases  and thus  it cools down . The "ice" you see outside  the surface of the tank is the water inside the  ambiant air which is getting  cooler creating outside condensation. This is proving a good thermal exchange .If you want to maintain good pressure in the tank, you must maintain the maximum exchange surface between the inside and the outside and above all not prevent this exchange by insulating the tank.
Even better , warm it up a bit.
So do not insulate the tank.

You can also reduce the cooling and maintain a good pressure inside the tank by supplying the burner in liquid phase. One drop of butane in Std Conditions is about 240 time its volume in gas. In other word , it wouldn't depressurize so fast and tremendously reduce the cooling effect . This is another subject.


As regards filling cigarette lighters, I fully agree, that was always an equally inefficient and hazardous process.
And yet , thousand of people does it every day !

If we do not allow for a small amount of bleed of then the displaced gas must go somewhere and the only place it can go to is up into the filling tank.
That's all gas laws and I am not very familiar with it ! Some will explain better than I can do but  the equilibrium vapor pressure of the liquid gas refers to the pressure exerted by the vapor of the liquid, at a given temperature, that is required to prevent the liquid from changing state .
In another word , we want it or not , depending of the ambiant temp , there always be +/- 20 % space above the liquid in a close recipient .

I am sorry not to be smart enough to explain in descent English but I am sure  that one of our member can do it a lot better than I do !
It is Sunday afternoon , no rugby at the TV and I had a good lunch ! ;-))

[Bunkerbarge]

I know it's a mistake, that is why I was using it as an example.

[KBIO]

I understood !    That was just to explain why to the others !

[1967Brutus]

Simon, If you don't open the gas tank outlet valve, albeit very slightly, as the tank fills with liquid the displaced gas has nowhere else to go but back into the disposable tank.  This disrupts the flow of liquid into the tank and makes filling very difficult. 

I agree with near verything you posted, but, not to be pedantic, this is 100% untrue. The fuel is a condensable gas, and by simple law of physics, the gas in both the bottle as well as the fuel tank are ALWAYS at exactly their poiling/condensing point, where the equilibrium between temperature and pressure is. As long as they both hav th same temperature, they will have the same pressure, and any liquid flowing from one container to the other will cause a bit of vapour to condense into liquid in the receiving container, and a bit of liquid to evaporate in the giving container.
When the disposable bottle is held upside down, and the connection between bottle and tank has been established by means of the filling adapter, the liquid gas will flow down by gravity from bottle to tank. It WILL be slow (I typically see flowrates around 0,5 grammes per second), but it WILL flow.

The ONLY two things that disrupt this process are
A) non-condensable gasses (air) in the fuel tank)
B) the fuel tank being warmer than the bottle (in that case, the pressure in the fuel tank will be higher, and the fuel will not flow).

To fill a fuel tank, all that is needed is that there is no air in the tank, and the tank to be filled being colder than the bottle. To achieve that, first filling (when new) is a short burst of filling with fully open gasvalve blowing off to atmosphere. This will drive out the air, and the liquid gas evaporating will strongly cool down the fuel tank. Close the gas valve and fill the now icy cold tank.

Once the tank is air-free, any subsequent filling can be done by just gravity. The heat from the hand holding the filling bottle is sufficient to keep the flow going (albeit slow, maybe 1 gramme per second) provided you do not hold the fuel tank with a full hand as well.

As for filling grade, a fixed number cannot be given, but personally I keep it below 80% volumetric for reason that overfilling can be seriously dangerous.
A too full tank, combined with movemnt of the model can cause liquid gas entering the fuel line due to sloshing. Since there is no appreciable pressure drop over the fuel line, this fuel will in large part remain liquid until it reaches the burner, and when it does, it will extinguish the flame. Gas will continue to flow out (if a gas attenuator is used, steam pressure will drop opening the fuel supply to full, worsening the problem) and thee boat will fill up with gas.
Attempts to relight the burner can be fairly disasterous.

For the maximum filling level, I fully agree with and STRONGLY recommend the use of a precise scale (a 0-500 grammes scale with an accuracy of 0,01 grammes smaller than a pack of cigarettes can be had for around 10 Euros via most shopping sites like AliExpress or Amazon etc).
Internal volume of the tank is easily estimated by the dimensions taking material thickness into account, density of LPG is 0,51 grammes per cm3 so it is easy to figure out how much your tank can safely hold.
Alternative, unscrew the filling- and gas valves and fill with water to figure out how many mililitres the tank will hold. No rocketscience.

[rhavrane]

Bonjour,
Another possibility to check the gas level is to install a glass pipe similar to the boiler ones on the tank :
https://youtu.be/JDXPLvyf5i4

[1967Brutus]

Excellent solution! Just be careful not to break the glass...

On board ships, pressurized level glasses are protected by a metal frame or cover, usually made out of a lengthwise halved piece of metal pipe.

On our boilers such a tubular levelglass is not too big a problem because the boiler is never removed while pressurized.
But the gastank usually is "handled" during and after filling, and as long as there is any liquid present, the pressure must be considered to be there and in full.

[rhavrane]

Bonjour,

Hopefully, I have never had the opportunity yet to navigate in closed premises, I am always outside because none of my tanks can be removed of their boats.
Especially in my enclosed boats like my tugs or cargos, I pay great attention to all connections and do not hesitate to use thread locker or PTFE tape to avoid any leaks.
Precision, the valves positioned on gas my tanks bought to French or German manufacturers are not designed with seals to be assembled and disassembled.
Examples : https://youtu.be/RXi9hN2orsc