Don Young's Black 5

[uuu]

Oct 29, 2020 5:39:11 GMT runner42 said:

... One thing is certain and that is all turns at SASMEE are right hand so it simplifies things a little. An aside does all clubs have loop layouts and all travel is in the clockwise direction?

Brian

It's a bit of a trek to get here. but Isle of Wight MES raised loop is anti-clockwise. Ground level is clockwise.

Wilf

[runner42]

Prior to starting the next major phase of build, I spent some time setting the valve timing. As built it ran on air but felt that it required a bit of tinkering to optimise the timing so it required removal of the front valve covers. When initially assembled I used Loctite 510 to provide the gasket sealing, which proved to be a folly. Loctite 510 is an anaerobic sealant and on such as small assembly acted like a screw sealant so removal of the 4 x 2 1/2 mm stainless steel retaining screws was a lengthy and hazardous activity. Thankfully stainless steel screws can withstand some abuse without shearing, unlike ordinary steel screws, When I eventually removed the screws it required some considerable force to remove the cover from its seating. The need for the screws was therefore unnecessary. I have used the same gasket sealant on all covers of the cylinders so I hope I don't have to revisit these.

On reassembly of the valve covers I shall use the Loctite Blue Maxx, which I have used extensively prior to discovering Loctite 510.

Brian

[runner42]

I have been tardy in ordering materials in advance and as such have been on the make do cycle. The job in hand is the regulator which is possibly a casting so on that basis I am going to have to change the design anyway. On the make do aspect I had to look closely at the scrap box to see if I could produce something to fabricate the body. It was touch and go that I could proceed or accept a 2 week wait for delivery. The part in question was a piece of bronze that I could use, but for that it was the old mother Hubbard syndrome, nothing suitable until I thought of using stainless steel.

The drawing of the regulator is shown


regulator drawing by Brian Leach, on Flickr


I managed to produce the fixed contact face and the output port from bronze. 


regulator body by Brian Leach, on Flickr

regulator body1 by Brian Leach, on Flickr

I intend to make the adjustable contact face from PTFE and the linkages from stainless steel. Does anyone see the substitution of bronze for stainless steel as a problem?

Brian 


 

[44767]

PTFE should be fine for the disc, although I made mine from stainless steel. It is best to have the two parts from different materials. The links are perfectly alright in stainless steel but the shouldered screws providing the pivots for them need to be bronze as stainless on stainless is a poor combination. Here's my one; it, too, was fabricated as I don't think there is a casting for this.

[runner42]

Thanks Mike for posting your version. How do you intend to fix the regulator in position? I am going to silver solder two lugs on both sides and modify the steam dome so the there is a flat that takes the screws from the fixing lugs. Using DY's method requires fixing to the boiler barrel, which I wish to avoid and remove the possibility of a leak.


Brian 

[Deleted]

Nov 26, 2020 21:44:42 GMT runner42 said:

Using DY's method requires fixing to the boiler barrel, which I wish to avoid and remove the possibility of a leak.


Brian 

Are you sure Brian?.. that sounds more like LBSC than DY...on Doncaster he has the regulator un-supported relying just on the fitting to the steam pipe. On mine the regulator body will be secured to the dome bush which has been modified with an inner flange for two screws to bolt into the regulator for extra rigidity.

Pete

[44767]

I have followed the drawing for this in that it fastens in the same place but I modified the dome to have a machined face integral with it. The regulator screws to the dome not the barrel.

[44767]

Nov 26, 2020 22:06:02 GMT @greenglade said:

Nov 26, 2020 21:44:42 GMT runner42 said:

Using DY's method requires fixing to the boiler barrel, which I wish to avoid and remove the possibility of a leak.


Brian 

Are you sure Brian?.. that sounds more like LBSC than DY...on Doncaster he has the regulator un-supported relying just on the fitting to the steam pipe. On mine the regulator body will be secured to the dome bush which has been modified with an inner flange for two screws to bolt into the regulator for extra rigidity.

Pete

Pete, this is the way Don drew it. Not a good design really.



As mentioned, I modified the dome to have the mounting face milled into it.

[runner42]

I have done a trial completion of the regulator, primarily to see if the use of PTFE for the movable disc is OK. Surprisingly PTFE provides a good air tight seal without the need to carefully prepare the surface by polishing if it were metal. All the fixings and the spring are temporary, but it operates as I would have hoped. The only issue is how robust the thread in the PTFE is, will it last a long time? Generally how does PTFE respond to steam heat, will there be changes that affect the operation?

Brian

regulator by Brian Leach, on Flickr

regulator2 by Brian Leach, on Flickr

[Neale]

I've been meaning to ask for a while but this reminds me - does anyone have a comment on the recent articles in ME on a new type of regulator for the DY Black 5? Someone has fitted an industrial process control valve (a kind of globe valve, I think) in place of the original disc valve as discussed here. It's a valve suitably rated for pressure steam operation and it is operated by the original control, couples to the original steam pipe, etc. Seems like something that would be easier incorporated at the build stage rather than a later mod but I have no idea how effective it might be. I'm a fair way off considering a boiler for mine but it's useful to pick up ideas as you go!

[Cro]

Brian if I were you I would put it in some boiler water and see what happens, I have a feeling it may end up fairly flexible and no longer flat.

The way grandad did it was a bronze version of your disc but with PTFE caps fitting into the holes which end up as your seal so the regulator works the other way round (if that makes sense).

Adam

[coniston]

I think as Adam says the PTFE will soften in the steam and no longer be stiff enough to seal or sufficiently strong to support the screws. You could make a bronze cap to encase the PTFE valve, the screws would fit into this and the cap would keep the PTFE from distorting away from the face, just a thought, not from direct experience.

Chris D

[runner42]

Thanks for the cautionary note, however some research has discovered that using PTFE is good for the adjustable disk and provides a good seal. Many ME's have used it successfully in this application. To overcome the noted problem of producing a thread in the PTFE, which is considered a weak spot, I have countersunk the mating surface to take countersunk screws and put a thread in the actuating arms, thereby removing the need for a thread in the PTFE.

Brian

[David]

Nov 28, 2020 8:14:45 GMT Neale said:

I've been meaning to ask for a while but this reminds me - does anyone have a comment on the recent articles in ME on a new type of regulator for the DY Black 5? Someone has fitted an industrial process control valve (a kind of globe valve, I think) in place of the original disc valve as discussed here.

Ball valves are used as regulator valves down here. I have not done so, so cannot advise on the type of valve or material. The only thing I can say is they can be a bit stiff and may need some freeing up, based upon what I've heard from people who have used them. I think they are more commonly put in the smokebox than the dome for the models they're used on down here, and the control rodding has to be a bit overscale or the working rodding hidden to overcome the stiffness with dummy scale sized rods on display.

[Jim]

I got this 'gas' tap some year's back in a ship's chandlery. The handy part about it is that it's easily disassembled and or adjusted simply by using a hex key to take out or ease the retaining ring that keeps the PTFE seals and ball in place.

I used its twin as the regulator valve on Boadicea, it seals without any issues and moves easily when in steam.

Jim

[Cro]

Brian, I’ve never known anyone use ptfe in disc form as you have, I honestly would try it in boiling water first. The other risk you have with the countersink screws is overtime they will wear away the ptfe holes and it will become sloppy.

I personally think it’s a bad idea and will be a potential disaster when in steam and you end up with a regulator wide open and nothing you can do about it.

Sorry to sound negative I just have doubts on that one.

Adam

[runner42]

Well I can't win a trick these days, everything is becoming a problem. On the regulator issue I thought I had proved the design and before making a good one, I operated the trial regulator to see that it worked OK. After many operations I noticed that the turning of the movable disk that sometimes it would transmit the turning motion through the retaining spring to the head of the holding pin and thereby unscrewing it. This also occurred on one of the countersunk screws effectively undoing the thread and pushing the affected arm away from the movable disk. I immediately thought of Loctite, but is there a better way?

Brian

regulator3 by Brian Leach, on Flickr

[flyingfox]

Greetings, I have tried PTFE in a slide regulator valve on a 71/4 A3, and indeed it did soften, collapsing into the port, jamming the regulator, however my friend John from Chelmsford uses the same system , but reduced the area of the port by silver soldering a bar across the middle of the port, which gave support to the PTFE slide & it worked fine.
However, I used a Stainless ball valve on my 71/4 Britannia, and it worked well, after I learnt the tricks, firstly, use the high pressure version, good for 50 bar, these have a gland on the spindle, and thus stopping pressure via the spindle collapsing the softened PTFE seat, and use the full bore versions. A special ball valve is made for steam, and I think it has a brass ball.
It gave beautiful, finger tip control, and always closed properly, even for pressure tests. the loco is now 5 years old, and used regularly with no problems.
I swear that I will never use any other type of regulator.
Brian

[Deleted]

Hi Brian

That's interesting, do you have details of the valve that you used please, I wonder if there's something similar to fit 5" gauge? I know that others have used ball valves, I just like the 'fingertip' experience that you have gained from the type that you've fitted.

Regards

Pete

[stevep]

I am posting these pictures in the hope that they may help.

To be honest, I have no idea where they came from, but clearly, someone was very happy with the result.





I plan on doing something similar when I get to fitting the regulator to my Pansys - although I will aim to fix the regulator to the dome ring, rather than drill the boiler shell.

EDIT - I see that the pictures have doubletop's avatar in the corner - so maybe they came from Pete.