Ball valve regulator

[JonL]

I was discussing regulators with my Common or Garden club boiler inspector and when the subject of ball valves used as regulators came up he said he would be very reluctant to pass a ball valve used on a boiler as the seals would be unlikely to be rated for the temperatures involved. I know that people don't tend to have any issues with ball valve regulators, but if I'm going to have trouble getting my inspector to pass it off then suddenly its not so ideal.

My questions for the collective brain:
1) What sort of temperatures do you expect a regulator to see? Mine would be in the smokebox attached to the superheater.

2) The one in the link below says it is steam rated (I've not looked at anything beyond that statement, it was just a convenient one when google popped up). Do you think there are any good arguments I could use to justify my use of that or am I flogging a dead horse? He is quite a common sense, open minded chap, so I think a polite argument based in fact would sway him.


screwfix valve

[uuu]

Here's another link with a similar 180 degree rating: Valves Online

There are people who use ball valves in the steam space, as I am planning to do on Jessie.

Wilf

[ianholder]

I fitted a ball valve in the dome of a 7 1/4" Hunslet, 4" scale, over 30 years ago and it is still as tight as the day it was installed. This was a brass bodied valve with ptfe seals. I have fitted the same valves in other engines since. As you are using it in the smokebox something higher rated would be needed as the temperature would be higher. Look at the valves that RS list, their no 499-2795 is a stainless valve, body and ball, and is rated at max 232*C and 68bar pressure. If that did not satisfy your boiler inspector get another one. Boiler inspector not valve!

[oldnorton]

As Wilf says, they have been in use. I would add that they are made of steam and heat resistant materials being stainless steel and PTFE, and are rated to 180 degC and several hundred PSI.

Rather than the budget plumbing valves, which probably will work anyway, you could try ones that are more designed for chemical and industrial use. I have found these that are 316 grade stainless and can be obtained in a smaller size of 1/8" BSPP with a 1/4" valve bore. I think some people have found the plumbing 1/4" BSP valves to be too big for the steam opening and almost uncontrollable in use.

pipeworksuppliers.co.uk/index.php?route=product/product&path=65&product_id=339

Norm

[JonL]

Brilliant suggestions all, thank you.

[Roger]

For reference, iF you're running at 90psi then the temperature the valve will see is 166C.

[steamjohn248advent]

We ve been using SS ball valves is all our locos since 2003 (7 1/4") ranging from an 0-4-0 Hercules to a 1 1/4 Ton K 1 Garret.

Same in a 27' coal fired steam launch. All came from Valves on Line.

No problems so far although none are in the smokebox.


Steamjohn

Land B (min) R. Museum of Power, Langford Essex

[pault]

Hi
These are rated for saturated steam, I have fitted 7 or 8 of them, maybe more. They seem to have a life span of 15+ years. When they do start to fail you just get a slowly increasing blow by, nothing spectacular. Being relatively inexpensive, and with careful design to allow easy replacement, the life span is not an issue. I normally throw away the handle and the brass operating shaft and replace the shaft with a two piece welded stainless steel rod. A half inch vale will comfortably supply a 7 ¼” loco. The configuration of the valves make fitting much easier than a normal straight valve.

flowtechnologyuk.com/product/BV07-12

[steamer5]

Hi Alan,
Reading thru the replies, & from other threads on here, with the valve fitted IN THE STAEM DOME there is no, or very little, problem, as the valves indicated have been good to 180 plus C. The issue for you is putting it in the SMOKEBOX!.

I seem to recall that there has been a thread here that somebody has done this but the locomotive was still under construction. Information on smokebox temps during running is very scarce, maybe Julian might have some info on the temps. Jim Ewan did a lot of testing, & a quick look at the article indicates that something like 600 to 700 F ( 315 to 370 C)is possible. As Roger points out the steam temp will be dependent on pressure so if you run at 90 to 100 psi then something like 166 to 170C, you then will need to add any superheat to this, probably not a lot (ducks for cover, well you CAN'T superheat wet steam!!). The worst temp the valve is going to see will be when stationary with the blower on, or coasting, as you will have little or no cooling effect of the steam. SO have a look for a hi temp valve, I would suggest if you can get one that's good to 400C bite the bullet & grab it....in small sizes they wont be cheep!

It will be interesting to see what you find.

Cheers Kerrin

[Tony K]

Jul 10, 2020 9:18:22 GMT steamer5 said:

....As Roger points out the steam temp will be dependent on pressure so if you run at 90 to 100 psi then something like 166 to 170C, you then will need to add any superheat to this, probably not a lot (ducks for cover, well you CAN'T superheat wet steam!!). .....
Cheers Kerrin

Just one comment - the regulator is before the superheater and the seat is PTFE which, I am told, "is stable and nontoxic at lower temperatures, it begins to deteriorate after the temperature reaches about 260 °C (500 °F), and decomposes above 350 °C (662 °F)."

Carry on Nobby and fit one.

[gwr7800]

As others have pointed out, I have used one in a standard Simplex for well over 20 years it’s still in steam although now with another club member!
Seem to remember it was just a standard valve, ie small plumbing type!
With my Cookington Manor did think about trying to fitting a ball valve, in the end I followed the drawing and used a disc in a tube!
Have fun experimenting,
Cheers
Chris

[Jim]

I fitted a ball valve regulator to the Britannia and it works perfectly with a good, smooth control as the regulator is opened. The particular valve I used has screw in ring to retain the PTFE valve seats in place which makes it very easy to either replace the seats when the wear or as I have heard happening in extreme cases, the PTFE expanding making the valve hard to open or close. That being the case it is easy to just ease the retaining ring for freer movement.

As others have done I replaced the actuating handle with a simple linkage that is operated by the the regulator 'push pull' rods as per the full size.

The valve

Linkage sadly I forgot to include the operating arm that replaced the original plastic handle

and in place in the smoke box. You can just see the operating arm coming down beside the threaded end to connect the blower steam pipe to the blower.

Jim.

[Gary L]

Jul 9, 2020 17:46:48 GMT pault said:

Hi
These are rated for saturated steam, I have fitted 7 or 8 of them, maybe more. They seem to have a life span of 15+ years. When they do start to fail you just get a slowly increasing blow by, nothing spectacular. Being relatively inexpensive, and with careful design to allow easy replacement, the life span is not an issue. I normally throw away the handle and the brass operating shaft and replace the shaft with a two piece welded stainless steel rod. A half inch vale will comfortably supply a 7 ¼” loco. The configuration of the valves make fitting much easier than a normal straight valve.

flowtechnologyuk.com/product/BV07-12

Common brass ball valves have a bad reputation in the marine world, due to dezincification. This can be an issue with boiler fittings too. Pay a bit more and you should be able to find them in DZR brass (De-Zincification Resistant) or possibly bronze. I've not heard of stainless versions, (which doesn't mean they don't exist) but they are often chrome plated, which might deceive the eye.

-Gary

[cplmickey]

Just bought a valve for my Baldwin and my feeling is that I want to fit and forget so I've gone for a 316 stainless steel valve rated to 200 degrees. It was £49 with the VAT - don't know how that compares with others but gives me peace of mind. Ian