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Post by Deleted on Oct 3, 2014 9:49:36 GMT
that's very informative Ben.. do you by chance have the same info for any Gresley pacific....I'm assuming that little changed between A1/3 and 4. I do know that 4472 as built had hydrostatic lubricators but these were soon replaced by mechanical ones, shame as I like the look of the backhead with hydrostatic fitted. Perhaps if you find yourself on the footplate of one of these fine beasts in the future you'd be so kind as to take a series of similar photo's to those above with descriptions of their operation, I will do all i can to incorporate them in my build with as many working parts as possible. well I would do that wouldn't I?.... Pete
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Post by Deleted on Oct 3, 2014 10:06:24 GMT
YEP----- might be applicable to The Bear.........must find some clear photos of The Bears' backhead !!
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Post by andyhigham on Oct 3, 2014 10:22:59 GMT
No----in the lubricator body itself-------- The sight glasses appear to be in pairs. Is this more redundancy? A glass in use and another in case of breakage/blockage for each circuit?
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Post by Roger on Oct 3, 2014 10:28:07 GMT
shouldn't there be two Tea Urns, if that's what that white jug is? I mean, that would be an emergency if one wasn't functional...
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Post by andyhigham on Oct 3, 2014 10:39:30 GMT
An empty brew can would be more of an emergency than a faulty lubricator
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Oct 3, 2014 10:55:21 GMT
re The Great Bear there are plenty of clear pics of the backhead of this loco and the early Stars in Russell and Nock.
alan, re the jockey valve you are quite correct that in the GWR instructions this is referred to as the 'W' valve. as you look at the valve, steam comes in at 9 o'clock from the fountain, and also at 2 o'clock (on small locos only at 2 o'clock), and the oil from the sight glasses (except that direct to the regulator) comes in at 3 o'clock. below this in line with the valve handle coming off at 3 o'clock is the feed pipe to the steam pipes in the smokebox.
the GWR sight glass assembly , as ben has described, has alsorts of other pipes and valves for filling, warming through in cold weather etc but the basic design varied only in capacity of the oil.
i have gone down to a 5/16" dia sight glass with success (quite a bit less than those commercially available), and i would be interested if anyone has made the sight glasses of less diameter and still be totally reliable and easy to see and operate. however what this means is that if you copy the GWR sight glass assembly accurately it will have to be a dummy. i dont see the point of fitting stuff to our locos that dont work (apart from loco lamps!)
cheers, julian
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Post by Roger on Oct 3, 2014 11:11:28 GMT
An empty brew can would be more of an emergency than a faulty lubricator I think there's a clear case for two sight glasses on the side of that Urn....
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Post by Deleted on Oct 3, 2014 11:11:56 GMT
i dont see the point of fitting stuff to our locos that dont work (apart from loco lamps!) cheers, julian Mine will work.....sorry couldn't resist.... this reminds me i still have all the electrics awaiting my attention for said lamps...very basic though so shouldn't take too long and will be a perfect job for doing indoors over the winter months... so much other stuff to do....it's never ending... Pete
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Post by Deleted on Oct 3, 2014 11:13:36 GMT
Are you taking commissions for these lamps Pete?
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Oct 3, 2014 11:14:09 GMT
hi andy,
the GWR instructions for the 5 sight glass type (shown in the above pic) state "all these lubricators have two glasses for each independant cylinder feed. oil may be passed through either (thus keeping one spare) or both of these glasses at the same time but the rate of feed must be adjusted to suit the number of glasses in use". (the 5th glass is for the regulator feed which can just be seen in the above pic on the right hand side).
there is also the smaller 3 glass type.
the single glass type is not covered by the GWR instructions i have that is still fitted to EARL OF BERKELEY in ben's pic (and also fitted to Dean Goods 2516 at 'Steam' in swindon).
cheers, julian
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Post by Deleted on Oct 3, 2014 11:32:17 GMT
Are you taking commissions for these lamps Pete? I can't take credit for the lamps themselves Ben, they are commercially available items, think I got them from Blackgates and very nice they are too...they are supplied as non working lamps although should be easy to convert, i'll of course give a full description of what's involved once they are finished... Pete
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Oct 3, 2014 11:34:22 GMT
( re pete's proposed working lamps, they dont have to be working/lit as such unless in darkness or reduced visibility according to the old BR rule book! )
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Post by Deleted on Oct 3, 2014 11:48:50 GMT
Always good to plan ahead Julian, who's to say I'm not going to fail in section on the V2 somewhen and be unable to move, it may get dark before an assisting engine arrives
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Post by Deleted on Oct 3, 2014 11:50:30 GMT
An empty brew can would be more of an emergency than a faulty lubricator ------------------------------amen to that, Brother !!
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Post by suctionhose on Oct 4, 2014 12:48:37 GMT
Interesting that the GWR system, which is more complicated than most, provides redundancy in the form of dual feeds for one cylinder. Our older engines had Detriot Lubricators with two feeds per cylinder and one for the air compressor (the later was often an add on to the side of a 4 feed Detroit). The two feeds to each cylinder went to the valve and the cylinder respectively so in fact neither were indispensable.
What surprises me is how little oil is required. How can 2 drops a minute - perhaps a small tea spoon full - be sufficient to lubricate a few square metres of high speed metal to metal bearing running at a couple hundred of degrees? Apparently it does well enough but it does test your belief.
David Wardale during his Red Devil work did quite a lot on cylinder lubrication to extend liner life (which was ridiculously short) as well as reduce oil consumption as an operational expense. A lot may be attributed to the method of introducing the oil to the surfaces. ie the atomisation and distribution.
Which brings me to the point that our oil systems for models are quite rudimentary in that regard. Whether mechanically or so called "hydrostatically" provided, oil is pumped into the steam pipe in the hopes that it splatters everywhere and does the job. That philosophy in itself suggests waste is inherent.
Recently, I have had the opportunity to compare a mechanical lubricator with a hydrostatic on the same engine operating in the same circumstances ie my own engine at our Club.
Sometime in the 1980's I made a bunch of mechanicals with the double oring pump and ratchet drive. Nine out of ten have been terrific. The one that gave trouble was tweaked and it too has been working well since.
After 20 years without more than an occasional tank clean I decided to change to a hydrostatic just for the fun of it. I have to stay of the mechanicals, they have not given the slightest trouble. The one just made redundant was a twin feed with separate tanks so the rate of oil consumption could be compared - it never varied. Both levels just went down in unison always. The volume delivered once adjusted to my satisfaction by the oring spacer never wavered. In all they have extremely reliable and satisfactory.
The hydrostatic made to replace it is larger than Julians but so is the engine's cylinders. Interesting thing is that at one to two drops a minute it seems more than adequate. The chimney is quite wet and some gets on me. By calculation; wheel dia, ratchet teeth, track length I find the mechanical is giving approx 20 drops per lap of club where only two or three drops from the hydrostatic is equivalent or greater volume of oil.
I guess drop size must be larger. But I also question whether the mechanicals deliver precisely their theoretical displacement. Another member has made similar analysis of his mechanical - being unhappy with it - and reports less delivery in service on the engine than it appears to deliver on the bench.
One important variable is speed. Roger and Pault have discussed this early this thread. Slow moving pumps have time for pressure and oil to bleed off. The popular "Foster Lubricator" has a release mechanism that fires a shot under spring pressure which makes sense although I have not been so unhappy with my simple mechanicals to warrant trying the Foster type.
The last point to make is about the exact point and method of introducing the oil to the valve or cylinder. I have not done more than think about this, particularly in reference to my NSWGR 50 Class which has slide valves between the frames with port faces vertical. How do I know the oil doesn't enter through top of valve chest with steam and just fall to the bottom missing the valve altogether?
One assumes because oil is found in the chimney that it went through the works. But to believe it went EVERYWHERE and lubed everything on the way is rather a leap of faith I feel. A traction engine owner having the oil introduced to the steam chest some distance away from the valve spindle reported excessive valve spindle wear. After relocating the oil feed with this in mind he found the problem went away.
So in summary, a reliable mechanical is very convenient and simple. How well they work is entirely dependant on sound design and manufacture. The so called hydrostatics as we refer to them, are great fun - not easily made, require more attention and are not for all drivers. Ample oil in and out is likely necessary to compensate for the lack of science in a model to properly atomise and distribute the oil where it is needed.
Hope the above additional is of interest.
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Post by Deleted on Oct 4, 2014 16:02:32 GMT
One way of "atomising" (after a fashion)is to introduce the pumped oil into the main steam pipe as soon as is possible after leaving the Dry header......... With my 5"G Parallel Scot that I used to run I did just that, replacing 2 Vee-twin mechanicals( one on either side --- with drive from the crossheads ).. with one mechanical behind the front buffer beam, in front of the centre cylinder, with its' drive coming from the old by-pass pump eccentric ( The pump being removed !!---Two live steam injectors is all it needs, just like it's full-sized cousin !!)....The main steam pipe was drilled and a threaded Bronze bush was brazed in ( in situ I might add !....Took a heck of a lot of cleaning but we did it !!)... A tapered nozzle of a set length was then screwed into this bush such that the end of the nozzle was mid-stream of the Superheated steam flow, its' fastest point............Initially I set the output at max. but after a few runs was able to significantly reduce it until the chimney lip had a soft, grey, light ash look to it.............Job done !!.............For those who can't quite grasp the idea try this}------------ a standard large bucket filled with water.........PUT just two drops of Fairy Liquid in and stir gently......NO FROTH, just a clear solution..................Notice how the water feels slightly oily or slippery ??-----------Well there you have it..The water represents the volume of steam used by say SIMPLEX in 1 minute----- the Detergent is the Steam Oil also used in a minute........APPROXIMATELY, for demonstration purposes...ie}---The steam PARTICLES have the Atomised Oil particles mixed in with them....Steam Oil is designed to do just this, whereas Automotive oil definitely is NOT !!----------------Also remember that each inlet of steam brings with it a FRESH CHARGE of oil.........
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Post by suctionhose on Oct 4, 2014 23:27:07 GMT
I'd to hear more about "best place to introduce the oil".
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Oct 4, 2014 23:48:27 GMT
hi ross,
i totally agree with you that where the steam oil is fed into the steam supply for the cylinders/valves deserves much closer attention in miniature. on many well known designs it is at some convenient location where the details can easily be added on the drawings without obscuring some other drawing detail, and totally ignoring a better location. in GWR locos the already atomised oil is fed into the hot header. this is where the oil is fed into the system on my 3.5" GWR KING, but the banjo connection is hideously awkward and requires a couple of special tools and also makes assembly/taking apart of the boiler and smokebox extremely difficult. i have done something similar to what alan did on his ROYAL SCOT on other locos.
on STEPNEY i have added a feed into the central steam chest on the valves between the inside cylinders arrangement but a bit higher than as shown on the drawings. i would prefer a feed instead into the main steampipe inside the smokebox but on a small 5"g loco such as STEPNEY with a drumhead smokebox the connections of the pipework into the smokebox would be very awkward and inaccessible.
as many will know, if you listen carefully to a loco working you can tell if the lubrication is ok. for example i can immediately tell if a mechanical lubricator has failed or the tank is empty.
cheers, julian
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robmort
Hi-poster
3.5" Duchess, finishing 2.5" gauge A3 and building 3.5" King
Posts: 172
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Post by robmort on Oct 6, 2014 9:44:05 GMT
Surely the obvious and best place to feed the oil is in the centre of the steam union pipe under the smokebox, especially on 2 cylinder locos. This is where I've done it.
Rob
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Midland
Elder Statesman
Posts: 1,870
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Post by Midland on Oct 6, 2014 9:55:21 GMT
Yes, I know the JOCKEY valve by that name and in that function as well--------It's just I had a part-memory that the condensing coils selector valve was either called the 3-way valve OR the J-valve because of it's shape........An atomising valve within the Jockey valve ??......I thought they were at the other end ie at the delivery end, (after the choke-)-where the oil is about to be fed into the cylinders.........JULIAN, here is a typical GWR footplate view .. Could you talk us through the various pipes involved with the Hydrostatic system as I'm beginning to think I've been labouring under a misapprehension all these recent years regarding what's actually happening........I see the condensing coils and the two pipes leading down to the main body.....the condensate water displaces the oil which moves up from the lower gallery--controlled by the screw adjusters----through the water in the glass tube, to the upper gallery....but then what ?? How does the jockey valve ( which I thought only had oil within it ) fit into the system then ??>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> How did you get this picture to work. I tried to post one for you on the 4472 cab and it was rejected. Not a LNER thing is it? David
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