# fuel attenuating valve: what do you know?



## Skeeterweazel (Feb 11, 2014)

I've recently learned that such a thing exists: a valve that regulates gas pressure to maintain a constant boiler pressure. I've done a little searching and have found a fancy electronic unit, but have seen mention of a mechanical unit that used boiler pressure as an input to regulate gas.

Anyone w/ experience or knowledge please chime in w/ your thoughts.

Thx.
Marty


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## weaverc (Jan 2, 2008)

Marty,
Many years ago, several of us on the east coast played with a mechanical adjustable gas pressure valve. I put one in my K-27 and later removed it. I think Jon Kling did also. 
See my separate message to you. By the way, the one I have is smaller (barrel is 1-3/8"x5/8")and less complicated than the ones mentioned below by Joe. You can have mine if you want it.


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## StackTalk (May 16, 2014)

There are a couple of which I am aware:

The more widely known is from Forest Classics and it is referred to as the BIX029:

http://www.forest-classics.co.uk/bix029.htm

I bought two of these myself, to use in a marine and a stationary steam application, but currently they are languishing on a shelf.  Reports are that they work pretty well.

The other regulators are by Anton and appear to be more sophisticated:

http://fabrice.bretagne.perso.neuf.fr/Les%20Accessoires%20vapeur.htm#regul

Anton makes a regulator and an automatic gas cut-off that will monitor water pressure and cut the gas when the boiler loses water pressure. At least one model has a "pilot" capability which allows gas flow for lighting the burner and then can be switched over to pressure control once the boiler is lit. Without this pilot feature, these valves need a bypass to allow boiler lighting which then must be closed when the boiler is up to pressure.

I have no first-hand knowledge of either product in use, but I have read good reviews on the Anton as well.

Cheers,

Joe

Clarification or confusion?

Since the BIX029 is to be set up to detect steam pressure, it looks like it functions to regulate gas flow with respect to maintaining steam pressure, but it does not function as a safety. It will increase gas flow when the pressure drops and reduce gas flow when the pressure pushes on the diaphragm past the adjustable set point, but if you run out of water, the valve will open fully in in a vain attempt to re-build pressure?

My translation of the Anton instruction seems to suggest that the valves start off completely closed and must be bypassed to light the boiler unless the pilot model is chosen. Once lit, the water pressure on the diaphragm opens the gas flow until pressure meets the adjustment or set point. Additional pressure causes the valve to reduce gas flow, but a complete loss of pressure also closes the gas flow, thus providing low water gas cut off.


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## rookie (Aug 30, 2010)

I believe Regner offers such a device. You could check with Jason at - The Train Department.


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## Chris Scott (Jan 2, 2008)

Stuarts Models, UK

Electronic Gas Valve
http://www.stuartmodels.com/accessories.cfm/mainaccess_type/9/the_type/Electronic Gas Valve

Unfortunately they offer no description of its workings at all.


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## Pete Thornton (Jan 2, 2008)

Skeeterweazel said:


> I've recently learned that such a thing exists: a valve that regulates gas pressure to maintain a constant boiler pressure. I've done a little searching and have found a fancy electronic unit, but have seen mention of a mechanical unit that used boiler pressure as an input to regulate gas.
> 
> Anyone w/ experience or knowledge please chime in w/ your thoughts.
> 
> ...


The question is - Why do you need one ? If your steamer runs quite cheerfully on a certain setting and you don't have to fiddle with it, why bother?
The same question comes when someone asks about using r/c to control the gas valve.

It is unusual if I have to adjust gas pressure during a run. Perhaps if the train is light and therefore the safety is blowing, I will turn it down a bit. Or if the train is heavier or the wind is cold, I'll turn it up, but then it needs no further adjustment.


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## StackTalk (May 16, 2014)

Pete Thornton said:


> The question is - Why do you need one ? If your steamer runs quite cheerfully on a certain setting and you don't have to fiddle with it, why bother?
> The same question comes when someone asks about using r/c to control the gas valve.
> 
> It is unusual if I have to adjust gas pressure during a run. Perhaps if the train is light and therefore the safety is blowing, I will turn it down a bit. Or if the train is heavier or the wind is cold, I'll turn it up, but then it needs no further adjustment.


Pete, your approach is probably indicative as to why few such devices are manufactured and sold - and if purchased, may be still sitting on a shelf, as in my case. 

They are not necessary, but then again, when it comes to a hobby many things we do are not, strictly speaking, necessary.

I read with interest the thread here about an electronic cruise control that someone on this site has built and is testing . . . and I would love to tinker with one of these one day, if I ever get around to it.

Necessary? No. Desirable? Perhaps.

Cheers,

Joe

PS: I am going to check the BIX029 to confirm that the gas valve is open when there is no pressure on the diaphragm. I suspect the Anton device is superior.


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## weaverc (Jan 2, 2008)

*More info*

Marty, see my comment above. A constant boiler pressure is maintained by the safety valve (I use pop valves). What I found that the gas pressure regulator valve did was extend the use of gas over time because it eliminated the over pressure at the beginning of a run. As I wrote earlier, I don't use the valve any more, so if you want it to experiment with, send me an email off line and I will send you a photo of it and give it to you if you want it. My email address is in the PM I sent you earlier.


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## oiler (Jul 8, 2014)

I'm actually looking for a couple of the forest classic ones if somebody is willing to part with them. Some people have good luck with them and some do not. I was told the electronic one is better. I have a Hemmens one on my clyde puffer and it works very well but good luck finding one. if anyone would like to sell me a couple or one please send me message or email me. I have paypal.


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## Skeeterweazel (Feb 11, 2014)

Thx all for your comments and offers. I will keep them in mind. At this point i'm just curious about this technology. These units seem rather large for my little loco and may be a challenge to get them to fit. After starting this thread last night i started wondering if i could make my own, something i could come up w/ that could be made and controlled by my Arduino microcontroller. Was thinking if i could find the right temperature sensor, and temperature was indicative of pressure, it would be easy for Arduino to move a servo connected to fuel valve. Just a thought.
Pete: i hear you. My fuel valve seems a little finicky. I think if i fill the tank all the way i get liquid out of the valve and into the jet, which is a problem i understand. But sometimes it seems the fuel output jumps for no apparent reason. I think the taper on the valve is rather course. Does anyone know of valves w/ finer control for Regner/LumberJack locos? And what about ambient temperature? Summertime here in SoCal it's been in the upper 90's. If loco was in house and i bring it out to run it, does the pressure in the tank increase significantly as sun hits the tank?
Thx again.
Marty


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## BigRedOne (Dec 13, 2012)

Train Department is selling fine tapered steam regulator values. Not sure if those would work as fuel regulator, though.

I understand ambient temperature will increase pressure of butane fuel, and heat from a running loco will also.


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## Kovacjr (Jan 2, 2008)

Skeeterweazel said:


> Thx all for your comments and offers. I will keep them in mind. At this point i'm just curious about this technology. These units seem rather large for my little loco and may be a challenge to get them to fit. After starting this thread last night i started wondering if i could make my own, something i could come up w/ that could be made and controlled by my Arduino microcontroller. Was thinking if i could find the right temperature sensor, and temperature was indicative of pressure, it would be easy for Arduino to move a servo connected to fuel valve. Just a thought.
> Pete: i hear you. My fuel valve seems a little finicky. I think if i fill the tank all the way i get liquid out of the valve and into the jet, which is a problem i understand. But sometimes it seems the fuel output jumps for no apparent reason. I think the taper on the valve is rather course. Does anyone know of valves w/ finer control for Regner/LumberJack locos? And what about ambient temperature? Summertime here in SoCal it's been in the upper 90's. If loco was in house and i bring it out to run it, does the pressure in the tank increase significantly as sun hits the tank?
> Thx again.
> Marty


 

When you fill all gas tanks you always have to bleed off the tank due to it being overfilled. All tanks allow you to overfill past your outlet valve as the valve vents when liquid reaches the top of the valve. Simply open the gas until it flows without spitting then close let sit and light up. No issues will arrive should you follow that each time you refill. You can also open the gas valve and when it spits stop filling.


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## Pete Thornton (Jan 2, 2008)

> But sometimes it seems the fuel output jumps for no apparent reason.


Changing temperatures around the tank will change the pressure. If you look at the Accucraft loco tenders, they usually have a 'water bath' around the tank, which serves to stabilize the temperature. Cool water in summer (we usually just pour some distilled water in there - and in some locos that's also the water feed tank for the boiler, so it has to be distilled.) I've run in freezing temps by filling the water bath with hot water from a small soup kettle.



> I think the taper on the valve is rather course. Does anyone know of valves w/ finer control for Regner/LumberJack locos?


 Ask Jason - he makes them for Accucraft locos. But I doubt you need one.



> And what about ambient temperature? Summertime here in SoCal it's been in the upper 90's. If loco was in house and i bring it out to run it, does the pressure in the tank increase significantly as sun hits the tank?


 Yes. See my comment about water baths above.

P.S. A lot of what you pay for when you buy an expensive engine is extra features that make the experience easier. My EBT #12 has a water pump in the water tank around the gas tank, so I can fill the boiler while hot and continue running. Many locos also have an axle pump and bypass, which does the same thing while the loco runs.
Do a google search for "site:mylargescale.com tender water pump".


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## Two Blocked (Feb 22, 2008)

I have used a Cheddar attenuator in my Big Boy for the past 15 years. It was and is a great unit that works a treat, and keeps a constant 45 psig reading on the clock no matter the load or grade. My Hudson sports a Forrest Classics unit that is a joy to use. Both these locos routinely haul 25 plus MDC box cars with metal wheels [think inertia], thus relieving the operator of the sometimes difficult task of adjusting fuel flow while under way. These are "well worth it" pieces of gear to have.


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## xo18thfa (Jan 2, 2008)

K.N. Harris has two ideas in his book "Model Boilers and Boiler Making"

Do a Google search for a PDF download of this book


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## dougiel (Jun 3, 2008)

Kovacjr said:


> When you fill all gas tanks you always have to bleed off the tank due to it being overfilled. All tanks allow you to overfill past your outlet valve as the valve vents when liquid reaches the top of the valve. Simply open the gas until it flows without spitting then close let sit and light up. No issues will arrive should you follow that each time you refill. You can also open the gas valve and when it spits stop filling.


Jay,

not quite true. Properly designed gas tank and filler valves do not need to have liquid bled off before being lit. All it takes is a bit of common sense in the design with the gas take off above the filler valve vent. In some good designs this is built into the bush the filler valve screws into.

DougieL


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## Chris Scott (Jan 2, 2008)

Stuart Models Electronic Gas Valve Instructions; 

http://1stclass.mylargescale.com/chrisscott/Stuart%20Models%20-/01-Stuart%20EGV%20-%20Electronic%20Gas%20Valve%20Instructions.pdf.PdfCompressor-747819.pdf


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## Chris Scott (Jan 2, 2008)

From Two Blocked;










I have attached a photo of the Cheddar fuel attenuator valve that I installed in one of my locomotives in 2000. It reads ambient boiler pressure via a streamline connected to the loco's backhead as a given, and then controls the flow of fuel to maintain that boiler pressure by cutting fuel flow in and out as demanded by changes in loads and grades. It is a g-d send to the model engineer who is trying to manage the inertia of a large consist train as they try to manage throttle and bypass pump settings, while preventing the ever present danger of accordioning the following long train should the locomotive falter.

KO-5


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## Kovacjr (Jan 2, 2008)

dougiel said:


> Jay,
> 
> not quite true. Properly designed gas tank and filler valves do not need to have liquid bled off before being lit. All it takes is a bit of common sense in the design with the gas take off above the filler valve vent. In some good designs this is built into the bush the filler valve screws into.
> 
> DougieL


 
I have locos from Accucraft, Roundhouse, Aster, Cheddar, Argyle and all allow the tanks to be overfilled. If you know of some that dont do tell.


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## dougiel (Jun 3, 2008)

Kovacjr said:


> I have locos from Accucraft, Roundhouse, Aster, Cheddar, Argyle and all allow the tanks to be overfilled. If you know of some that dont do tell.


Thats strange Jason because non of my Roundhouse loco's have a problem with this. Neither do my gas tanks made by Tony Sant.

All my Accucraft ones do though,

No problem with my Aster's as they are all meths (alcohol) fired .

DougieL


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## Steve Ciambrone (Feb 25, 2014)

None of my Roundhouse engines require the liquid to be vented before lighting the burner.

Steve


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