Smoke box regulators

[Jim]

The plans for my 5" Britannia, 'Boadicea', call for a twin poppet valve regulator in the smoke box.
Has anyone on the site had experience (good or bad) with these type of regulators?
As an alternative I have looked at a modified 'Twin Disc' type regulator described and used by Les Sheppard in his NSW C38.
Any thoughts comments would be very welcome.

Jim

[Deleted]

Hi Jim,

Modelworks have supplied a commercial plumbing fitting for the regulator, as shown below - it appears to contain a steel ball rotating in a PTFE-type seating. I'd be interested in other peoples' views of this type of fitting.



Regards,

John

[waggy]

Hi Jim,

I'd be very wary of using the above type of valve for a regulator.

These things are designed to isolate a water supply or whatever you decide to put through it, probably no more than once a year at most!

Think how many times during a run the regulator is opened and shut? I suggest the valve would wear fairly quickly.

I asked a similar question to Jim regarding the poppet valve regulator but don't recall any replies.

Waggy.

[Shawki Shlemon]

Many years ago I built c38 with the regulator mentioned , other than some leaks that were fixed it worked OK . On the other hand I designed a regulator for 5" engine and fitted it to a few including one on C 36 similar to C38 but 4-6-0 and slightly smaller in the smoke box ,both engines are sold now , the 36 is in our club and runs every month without any problems . To see the design go to my web site on page 7.You will need to change steam inlet and outlet arrangement to suit your engine .

[gilesengineer]

Ball-Valves make exceeding good regulators. We now-a-days tend to use nothing else in 10 1/4" gauge. They are very sensitive, and 100% reliable in heavy service. The only time we had a problem was when the linkage wasn't set up properly on one loco, and so the valve was fractionally open when the regulator handle was closed. This meant that over time the PTFE extruded itself through the opening, making it impossible to fully shut off. They are easily obtainable in most BSP sizes from places like the 'Pipe Centre' and other trade plumbing supply places. In 10 1/4" gauge we use 1/2BSP, or 3/4BSP on the biggest engines.
It is possible to get right-angle valves as opposed to in-line valves. This can make fitting it into the boiler much easier.....

Waggy is right to excercise caution though. You do need to use a steam rated one. Typically, these have red handles. don't use the yellow or blue handles, as these are not rated to stand the temperature.

All ours are mounted internally in the boiler - I wouldn't try putting them in the smoke box with its higher temperature unless it was shielded...... (having seid that, John's post infers that Modelworks do.....)

Giles

[ausdan]

was only talking abt regulators last week, I was suggesting I wanted to have a external type and the boiler inspector commented that he had a smokebox fitted regulator on his loco, with one of the benefits, you can easily undo the pipe work and gain quick access if needed .

Have seen quite a few of 7.25 locos use the ball type valves....

[Jim]

Thanks chaps for all the replies so far.
I hadn't given commercial ball valves any serious consideration for use as a steam regulator, perhaps I should. It would certainly make the linkages to the outside of the smoke box much easier to fit.
Kind regards
Jim

[chameleonrob]

jj said:

Hi Jim,

Modelworks have supplied a commercial plumbing fitting for the regulator, as shown below - it appears to contain a steel ball rotating in a PTFE-type seating. I'd be interested in other peoples' views of this type of fitting.



Regards,

John

I'm pretty sure thats what our club loco uses and after five years of heavy use is still as good as new.

rob

[richardwilliams]

I can speak of both the twin pop style valves and the gas valve(that's what I used). The twin pop valve as per drawing was terrible, it gave too little steam (first valve open) and too much steam (second valve open) With the first valve open the loco did not move.
The gas valve is a great improvement, certainly I recommend you go that way.

[Jim]

Thank you Richard, your comments are very helpful and confirm my suspicions regarding the poppet style valves. Thanks too to all the others who have shared their views and experiences on this matter.
Jim