Milner Hunslet regulator

[mwfanwy]

Hi All, Can anyone please provide some guidance or a proven design for using a ball valve as the regulator instead of the original Milner design which I am told is not reliable? The boiler is a copper one by John Ellis, but the regulator boss has not yet been drilled/threaded. Thanks in advance guys if anyone can help.

[pault]

Hi
Commercial ball valves make very good regulators, and are available in a variety of materials to suite your tastes. If you can find one like this you are laughing.
www.vip-ltd.co.uk/dynamic/viewitem.php?item=01/0094/015

Unfortunately this company only do these in ½” BSP which is ideal for 7 ¼” although may be a bit small for some narrow gauge. The straight through ones work fine it’s just arranging the operating rod or the main steam pipe that is a pain. I have retro fitted about 5 of these and they give a smooth progressive regulator which is trouble free for many years.

The oldest one i have fitted is about 15 years old and still works fine.

Regards
Paul

[ejparrott]

Nov 23, 2012 22:49:49 GMT pault said:

Unfortunately this company only do these in ½” BSP which is ideal for 7 ¼” although may be a bit small for some narrow gauge.

Its an interesting question actually, just how do you size a ball valve for use as a regulator?

[uuu]

Can you fit this inside a boiler, or is it only an outside option?

[ejparrott]

No reason not to fit inside

[Boadicea]

Nov 24, 2012 7:43:10 GMT ejparrott said:

Its an interesting question actually, just how do you size a ball valve for use as a regulator?

Suggest it should be the same size bore as the output tube.

No problem in mounting inside a boiler but probably best to use a valve made in stainless. These are readily available and usually cheap.

[suctionhose]

Ball valves have been commonly used in Oz for donkeys years.

I have mine, mounted inside the dome, out for the first time in 15 years at the moment. Nothing wrong with it. They do leak sometimes during hydraulic tests even if perfect in steam.

Mine is an 8mm stainless one of no special spec. You can get steam / gas / hot water ones these days.

As for size, the throttle opening is usually less than the steam pipe ID. Why? dunno... A bit of wire drawing to dry the steam maybe?

With cylinders 2"bore x 3" stroke, an 8mm hole open about 75% at full throttle is entirely sufficient.

[gwr]

Mwfanmy, did you manage to sort out your regulator? I have just taken delivery of a milner hunslet boiler and I am looking to fit a stainless ball valve as a regulator. Did you purchase the one on the attachment? (vip) if so how did you fix it to the backhead?

regards

Daniel

[ejparrott]

My Manning Wardle boiler is a modified Milner Hunslet design, and I've designed the dome bush in such a way as to support it. Easy for me, the boiler's not built yet. Instead of trying to support it off the backhead, why not put a sandwich plate in the dome joint, with the regulator valve attached to it instead?

[gwr]

That would be easier to support the valve, and i could cut a window in plate to enable to line up the main steam pipe with the regulator valve. That would reduce the amount of work required on the backhead. Thanks for the idea. Daniel

[marshall5]

I wrote an article on just this subject in a recent issue of "Peveril News" the newsletter of the Manx Steam and Model Engineering Club - I hope it answers your question. I used a 1/2" valve as the main steam pipe was 1/2" and I didn't want to restrict the steam flow but having used the loco all Summer I think a 3/8" one would have been adequate. Ray.

Attachments:

ball valve.doc (671.5 KB)

[ejparrott]

Funny....I've just been and looked at my boiler drawing and regulator again....I think I might re design it to exactly the method I prescribed! I've got some 1.5" AF hex stainless at work which I could use to pull the ball valve up to a plate and then it'd be very rigid.... Dome bush would be easier to make too... Nothing stopping me dropping the regulator down come to think of it and straightening my main steam pipe out too...


hmm....

[jma1009]

i wish these valves were available in a smaller size for 5"g as i'd happily give them a try! the PTFE sleeved ball valves also look very interesting but again too big for 5"g - at least the right angled valves are too big.
cheers,
julian

[johnkeates]

I'm surprised that no-one has mentioned Gordon Smith's ingenious design using a 5/16" ball in a regulator fitting inside the inner dome on a Simplex. This was published in "Engineering in Miniature" May 2008 and in my experience works well.

The ball orifice (annular gap on full lift) needs to be scarcely larger than the combined orifices of the safety valves as these are designed to take the steam produced with a full grate working with full blast pipe assistance as happens at each annual steam test.

[mwfanwy]

I have finished the construction of my regulator valve but not tested it yet as I'm still finishing off the rest of the boiler fittings as and when time allows. I'll take some photos of progress and post them here when I get a chance.

[mwfanwy]

Some photos of the (slow) progress to date:
28/10/13 Additional photos added:

Attachments:

[jma1009]

super pics! what a lovely boiler and fittings - i note the boiler is by john ellis.

well done with the fittings and regulator which looks excellent!

cheers,
julian

[andrewsleigh]

mwfanwy
can i ask how you sealed the steampipe to the valve?

cheers

[fizzy]

Hi Julian - all. I fitted a small(the smallest screxfix sell) into my 5inch steel boiler. Its a bit of a faff but they work very well.