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Post by delaplume on Mar 8, 2021 21:26:25 GMT
Page 68 of LBSC's "Shop, shed and road" re-print by Martin Evans...ISBN = 0 85242 708 5 ....Argus books, 1979....}-------------Known as Column gauge the idea was to stop water surge affecting the level readings.... If you look at fig.4-3 that is exactly the set-up of the later GWR gauge glass fitting, complete with the pair of test cocks........
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Post by manofkent on Mar 8, 2021 21:51:42 GMT
Malcolm and Delaplume.
Thanks for answering my query.
Most interesting. I will give it a try when time allows. The water level shown in my 3.1/2 gauge locos does bounce around quite a bit .
John
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Post by coniston on Mar 8, 2021 22:51:55 GMT
What wouldbe the minimum id of an extn pipe to extend a water gauge out from the backhead so that a true level can still be seen in the ghlass? hope that makes sense! I am guessing that the id of the glass would be a good start, if so what is the od and id of the gauge glass suitable for 5in loco? Ron If I was extending the water gauges away from the back head I would make some hex bronze hollow pillars, threaded external to screw into the boiler and the same internal thread for the gauge glass fittings. Make the bore as big as you can whilst retaining sufficient strength in the male thread. So for 1/4" x 40 I would suggest 5/32" bore and 5/16 x 32 then 3/16" or even 7/32" bore should be ok. Bigger diameter gauge glass will suffer less with capillary action showing slightly false readings (high) IIRC both my 5" locos have 1/4" or 6mm OD glass, I assume the bore to be about 5/32 / 4mm but haven't measured it. Having said that for my A3 I have two of Dave Nobles very nicely made 3 cock water gauges which are 1/4" x 40 threaded fittings to match the Don Young boiler, so I guess the glass is probably 3/16" or 4mm OD. Chris D
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Post by suctionhose on Mar 8, 2021 23:11:13 GMT
In case this is of interest, this is my false backhead. The mountings for boiler fittings are just extended bushes upon which the false backhead fits over. I can't remember what I did to ensure the surface was flush with the the bush but it is and the end appearance is that the flanges are on the surface of the false plate. With respect to extended tubes for water gauges - I've had a few - there is a tendency for the water to boil in the bottom tube as soon as the pressure drops causing steam bubbles to stream through the glass. The only solution for this is to ensure the tube is air cooled sufficiently to adjust to temperature changes rapidly. You can get way with a long tube on the steam end of the gauge glass - the typical American setup is just that - but there are limitations on the water end. That said, the extension required for a false backhead should present no issues at all.
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Mar 8, 2021 23:52:17 GMT
Malcolm and Delaplume. Thanks for answering my query. Most interesting. I will give it a try when time allows. The water level shown in my 3.1/2 gauge locos does bounce around quite a bit . John The extension column (GWR pattern) is supposed to reduce oscillation in the water level, but I don’t see how it can. What is often missed though, is the big advantage of having the top and bottom glass mountings held rigidly in relation to each other, and unaffected by any movement of the boiler plates. Worth doing for that alone I’d say. If only I’d thought of that before! Gary
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Post by delaplume on Mar 9, 2021 2:58:54 GMT
Hi Gary......Did the American S160's on loan to the UK have the same type ??.........
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Post by RGR 60130 on Mar 9, 2021 8:56:08 GMT
Hello Ron, I've just checked the drawing and Michael shows the gauge glasses as being 1/4" diameter. The A1 needs the stand-offs to be a little longer than normal too so they clear the regulator shaft. If you scroll down this link you will see how Alan Marshall has done his. a1peppercorn.com/in-cab-items/I hope this helps you, Reg
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Post by silverfox on Mar 9, 2021 11:07:08 GMT
THanks
The Reg cavalry appeared over the hill
Some ;ovely little things in that
Thanks Again to all who replied
Ron
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Mar 9, 2021 11:51:29 GMT
Hi Gary......Did the American S160's on loan to the UK have the same type ??......... Hi Alan No idea I’m afraid, but I’ve something stirring rustily in my memory that says it was one of the ideas Churchward got from the States, so it’s quite possible. Could be completely wrong though. Gary
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Post by Deleted on Mar 9, 2021 12:04:19 GMT
Hello Ron, I've just checked the drawing and Michael shows the gauge glasses as being 1/4" diameter. The A1 needs the stand-offs to be a little longer than normal too so they clear the regulator shaft. If you scroll down this link you will see how Alan Marshall has done his. a1peppercorn.com/in-cab-items/I hope this helps you, Reg Hi Reg would you by chance have that drawing of the reverser indicator mech? It could help me greatly when I get there. Regards Pete
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mbrown
Elder Statesman
Posts: 1,720
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Post by mbrown on Mar 9, 2021 13:00:27 GMT
Hi Gary......Did the American S160's on loan to the UK have the same type ??......... Yes, they did. As in most US practice, they had one water gauge plus some try cocks. The water gauge had screw-down stop valves in place of the top and bottom cocks that we are used to in UK practice. The one for the bottom fitting was close to the gauge, but the top cock was just one wheel valve among many and one would have had to trace the pipe run to see that it was the Water gauge cock. It is suggested that unfamiliarity with the arrangement for the water gauge cocks led directly to the two fatal explosions due to low water on these locos . There is a cab photo and diagram of the fittings in the book "Over Here: The Story of the S160s" by R N Huggins published in 1980 - probably out of print but you may get a second hand copy on Abe books if you were interested. Malcolm
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Post by RGR 60130 on Mar 9, 2021 13:12:02 GMT
Pete,
I most certainly have the drawing and will try to photograph it for you.
Reg
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Post by Deleted on Mar 9, 2021 15:56:10 GMT
Pete, I most certainly have the drawing and will try to photograph it for you. Reg Thank you, Reg.. Kind regards Pete
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Post by delaplume on Mar 9, 2021 17:29:57 GMT
Hi Malcolm,
quote}--- "There is a cab photo and diagram of the fittings in the book "Over Here: The Story of the S160s" by R N Huggins published in 1980 - probably out of print but you may get a second hand copy on Abe books if you were interested."
I've just had a look and yes, I can have one for £52 !!
I'll try elsewhere ---------- it certainly looks a good book ---------- thanks for the tip
Alan
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mbrown
Elder Statesman
Posts: 1,720
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Post by mbrown on Mar 9, 2021 19:09:37 GMT
Blimey! Mine cost about £2.50 I think (albeit decades ago....) . Abebook prices can be quite variable and if you keep looking a much cheaper one may crop up. Meanwhile, although the glossy paper plus my poor quality camera don't help clarity, here are the two most relevant pages..... IMG_20210309_190135 by malcolm brown, on Flickr IMG_20210309_190403 by malcolm brown, on Flickr Malcolm
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Post by Oily Rag on Mar 9, 2021 22:16:37 GMT
Hi Jim, You might like to consider linking the upper and lower arms...This makes it very easy to shut off the gauge glass in a hurry.... With the gauge glass cocks linked, how did one do an individual passage way blow and test ? Such as steam closed and open water and drain to blow the water passage way and ensure it is clear and then close water and open steam to blow and ensure the steam passage is clear. Down here that is all a very must do when operating a boiler and on hand over. With them linked you are blowng them but both at the same time which I thought could be misleading. Our gauges have a ball valve between the drain passage and the glass so if a glass pops it should close.
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Post by delaplume on Mar 10, 2021 4:50:36 GMT
Yes, you're quite right about separate testing......I think we removed the pin in the top arm to do the test then replaced afterwards..but don't quote me on that as it's been a while ( 20 years ) since I was last active on the full size.... Here's a better view on "The Earl" at Welshpool...........
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Post by 92220 on Mar 10, 2021 9:14:27 GMT
'scuse my ignorance but what is a false backhead? Evening Andy False is probably the wrong terminology, we are referring to the backhead cladding, or at least I am.. Pete If anybody is interested in the correct description: the B.R. drawing calls it a "CLOTHING BACKPLATE", so Pete is right. The word "false", is the wrong word in this context. Bob.
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Post by andyhigham on Mar 10, 2021 9:55:05 GMT
A point on the "American" style gauge. The top fitting on my Shay was connected American style to the turret/manifold, when I turned on the injector the water shot to the top of the glass and stayed there until I turned the injector off
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