Gas valve regulator

[Deleted]

I read in a thread recently on Face Tube, You Book or whatever it is called a mention of the use of gas valves (available from Screw Fix for just a few pounds) for regulators and that they are used quite regularly nowadays. Having never seen one in use for this purpose does anybody have any photographs or diagrams of said item in situ?

[marshall5]

Many people have successfully used ball valves as regulators however I doubt the ones from the likes of Screwfix are suitable - others may disagree. I purchased, at considerably greater expense, one that was not only pressure rated but also temperature rated as suitable for steam use. For the first few months it was brilliant - no blanking off for hydraulic needed and it didn't leak a drop. Unfortunately, as time went by, it began to pass steam and I scrapped it. I suspect, that because in use it was only 'cracked' open most of the time the seal had eroded on the edge.
I'm sure that suitable ones are available but make sure that it is steam rated for temp. and pressure. The most difficult bit is usually working out how to connect it up. There have been several posts on the subject, a search should reveal them.
Cheers,
Ray.

[Tony K]

Orville, as Ray says, there are numerous threads on this.
Jim uses one in the Boadicea thread - try December 26, 2014.
On the whole it boils down to the following for me....
They appear to work well and feedback is good, although many of them are just about within spec on temperature and probably should not.
They are cheap and replaceable.
Most are brass which is not the best because of de-zincification.
If you search harder you can find stainless versions for a small additional cost - I would recommend that approach.
Just my opinion.

[uuu]

I'm lining up to fit a ball valve in Jessie. Since the loco is way off being finished, I'll not know how sucessful it will be. So I'm designing things so I can make a disc valve much like the drawings to swap over if things go wrong.

Sorry about these messy sketches: The first one is mostly the original layout - but experimenting to see how big a hexagon would fit in the dome - and how much higher than standard I could get the operating mchanism to go.



Then a sketch showing a modified dome top, to give a bit more room, and the view from above of how things would fit. With a smaller valve - I decided the big one wouldn't go.



And here's the dome top, with a valve. You'll see I've turmed off part of the valve, to give a bit more clearance, and to avoid too big a pocket for water to gather.



As I said - time will tell...

Wilf

[marshall5]

I used a 1/2" BSP right-angle ball valve in my 4" scale Hunslet but I'm sure a 3/8" one would be more than adequate. When the seal failed I used the body of the valve as the basis for a screw-down type regulator so I didn't have to alter anything else.
Ray.

[Jim]

Gas valve regulators are used a fair bit out here and as far as I'm aware with no real problems.
I have spoken to one modeller who found the PTFE valve seat expanded under heat and jammed the regulator shut....luckily. He solved the problem by removing the PTFE seat and shaving a few thou off and has had no troubles since. The valve I'm using has a removable retaining ring for the valve seal making easing or replacing it relatively 'easy'. I have also made up a 4 spares PTFE valve seat in case I need them in the future. Like so many things in this hobby a lot depends on what you prefer.

Jim
 
This is my valve.



..and installed with the operating linkages attached. It's hard to make out but I made the bottom link woth long open ended fingers that slide over the pivot pin on the operating arm. It allows for angular movement and can be lifted off if the crank arm needs to be removed.

[Deleted]

Thanks for all the above, much appreciated.

[doubletop]

NZ has large dairy and wine industries so stainless parts are easy to come by. These are rated for steam and 200degC

www.anzor.co.nz/ball-valves/product

Download the spec sheet.

Here is my Dart with one fitted to replace the hopeless Stroudley. With all the fittings in place 80psi of air leaks down to 50psi in about 4 mins. I gave up timing how long it took to get down further.









Pete