jma1009
Elder Statesman
Posts: 5,900
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Post by jma1009 on Sept 2, 2014 12:11:19 GMT
  as there has been quite a bit of discussion at various times regarding these things, the above article i wrote some years ago (copyrighted) might be of interest and promote a bit more interest and dispel a few myths regarding these gadgets. cheers, julian |
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Post by Deleted on Sept 2, 2014 12:19:59 GMT
Very nice of you to post this Julian..  I would really, really love to have hydro-static lubrication on 4472...alas if strictly following the prototype I can't....  Pete |
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Post by Doug on Sept 2, 2014 14:18:07 GMT
thanks Julian i just might try this out on my butch, I hate the position of the lubricator its a nightmare and impossible to service without a big stripdown, this would be a great little project too.
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gwr7800
Part of the e-furniture
Member of Portsmouth mes
Posts: 384
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Post by gwr7800 on Sept 2, 2014 15:56:07 GMT
Very Informative in deed ,didn't realise that you need a "choke" but drilling the nipple is a good idea ,I've been using a hydrostatic lubricator for years on the Manor it works well the fluid I first tried was very salty water it worked ok but the glycerine works better! Regards
Chris
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Post by Roger on Sept 2, 2014 16:33:17 GMT
Thanks for posting that Julian, I'll copy and absorb that. So much to think about!
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Post by Deleted on Sept 2, 2014 16:33:55 GMT
I'm thinking of trying a hydrostatic on the 5" 0-6-2 when (if!) I ever get that far, mainly because I've never fitted one before and the idea of a large oil tank that will last a day appeals.
I believe the type of steam oil used makes a difference. Too thin and it tends to emulsify in the tank filling the sight glass with gunge!. That used to happen to a friends 2½" gauge loco. I had it to do a bit of work on it and I filled the tank with the heavy steam oil that I use and it all worked perfectly, until my friend filled it up with his thinner stuff again!
Doug - you need a spare steam valve to turn the steam supply to the tank on and off. You might not have one on Butch?
John
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Post by Roger on Sept 2, 2014 16:56:33 GMT
It's interesting that the Glycerine doesn't want to work its way down into the oil tank since it's heavier than the oil. Is it the surface tension of that and the size of the No. 78 hole that stops that from happening?
I'm really surprised at how little oil you use. I guess most people wouldn't dare go that lean with a mechanical pump because you couldn't be sure it was working or not. Being able to see the oil float up the glass is a real bonus and I find them visually appealing too.
I'd be interested to see a sketch of the complete system, where the valves are etc and how the one pipe should be joined to the steam feed to ensure that both cylinders get oil. I suppose you could always have two sets of sight glasses and two feeds.
Another thing that comes to mind is that if a mechanical system with a variable output was fitted with a glass like that, you could trim the output in a way that can't readily be done without that.
It's certainly an interesting system and well worth considering doing. Now I really don't know which way to go.... anyone got a coin?
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Post by Doug on Sept 2, 2014 17:11:31 GMT
I'm thinking of trying a hydrostatic on the 5" 0-6-2 when (if!) I ever get that far, mainly because I've never fitted one before and the idea of a large oil tank that will last a day appeals. I believe the type of steam oil used makes a difference. Too thin and it tends to emulsify in the tank filling the sight glass with gunge!. That used to happen to a friends 2½" gauge loco. I had it to do a bit of work on it and I filled the tank with the heavy steam oil that I use and it all worked perfectly, until my friend filled it up with his thinner stuff again! Doug - you need a spare steam valve to turn the steam supply to the tank on and off. You might not have one on Butch? John Hi John i have a very dead injector which i could use the valve for but the whole mainfold needs to be repaced as the valves are left to right (need to face the driver ideally) the injector is not required at this point anyway as i have a good hand pump (i only use infequently) and a quite healthy axlepump. its all a bit academic currently but it would be nice to test the hydrostatic system on butch before i get to that point on speedy. |
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Post by Doug on Sept 2, 2014 17:15:02 GMT
It's interesting that the Glycerine doesn't want to work its way down into the oil tank since it's heavier than the oil. Is it the surface tension of that and the size of the No. 78 hole that stops that from happening? I'm really surprised at how little oil you use. I guess most people wouldn't dare go that lean with a mechanical pump because you couldn't be sure it was working or not. Being able to see the oil float up the glass is a real bonus and I find them visually appealing too. I'd be interested to see a sketch of the complete system, where the valves are etc and how the one pipe should be joined to the steam feed to ensure that both cylinders get oil. I suppose you could always have two sets of sight glasses and two feeds. Another thing that comes to mind is that if a mechanical system with a variable output was fitted with a glass like that, you could trim the output in a way that can't readily be done without that. It's certainly an interesting system and well worth considering doing. Now I really don't know which way to go.... anyone got a coin? from the trouble i have had i would definately say go for a hydro system if you can bonus is they look amazing too i saw a Paddington at the model show last year with two sight glasses it was a awsome! i will dig a photo out.  |
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jma1009
Elder Statesman
Posts: 5,900
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Post by jma1009 on Sept 2, 2014 21:05:29 GMT
hi roger, the glycerine doesnt work its way down to the oil tank because of the small dia pipes (3/32" dia) used plus the very small size of the jet. when the loco has steam up you open the steam valve to the pipe from the valve on the backhead to the bottom of the oil (displacement) tank and so the whole system is pressurised at a pressure greater than steam chest pressure whilst the loco is in steam. at the same time you open the needle valve to a pre-determined position. when back on the steaming bays after a run and whilst the loco is still in steam the 2 valves are closed. i should perhaps add that if the steam stop valve doesnt close properly/isnt closed and the needle valve isnt closed before dropping the fire and blowing down the boiler etc oil can be sucked into the glass from the pipe to the steam chest, and glycerine sucked down into the oil tank as the boiler cools down and creates a vacuum within. you only ever make this mistake once! ive posted the following pic before, but shows top left the steam stop valve on the manifold feeding down to bottom of the oil tank hidden under the cab floor, then the pipe from the top of the same tank going to the additional stop valve actuated by the GWR type regulator quadrant, then this feeds to the bottom of the sight glass. as the loco has inside cylinders with a single steam pipe to the steam chest only one sight glass is required. cheers, julian  |
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Post by Roger on Sept 2, 2014 21:29:19 GMT
Hi Julian,
I love that backhead with all the clutter and feel of a full size locomotive.
That all makes sense to me now. I presume the valve operated by the regulator is in between the steam valve you mentioned and the bottom of the oil tank. I can see that 1501 has a similar mechanism for operating a valve like that.
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jma1009
Elder Statesman
Posts: 5,900
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Post by jma1009 on Sept 3, 2014 9:38:38 GMT
a couple of points:-
on the above PADDINGTON pic supplied by doug the pipes from the 2 sight glasses appear to be shown as going through 2 hollow stays through the boiler. this is uneccessary, and in fact inadvisable, as the whole sight feed assembly should not be allowed to get too hot, plus i would dread to to think what it would be like having to do the additional pipework in the smokebox even in 7.25"g!
the oil tank should also be in a position where it doesnt get too hot. on the above pic i posted the tank is behind the rear axle but not far from the glare from the ashpan and so is lagged.
re john's point about grade of steam oil, ive used both the finer refined grade and the very thick stuff and neither makes any difference to the operation of the sight glass etc.
on roger's SPEEDY thread, Ben questioned the use of the term 'hydrostatic' and i would agree with him (the late Basil Palmer explained this in some detail in ME many years ago) but i see no reason to confuse matters by departing from the generally used description for these types of gadgets!
cheers,
julian
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Post by suctionhose on Sept 3, 2014 12:35:56 GMT
Thanks for this info Julian. Actually the reason I joined this forum in the first place was thru a search for Hydrostatic Lubes and Julian's name came up. Of course Julian's article had not been made available at the time so I pressed on regardless. The pic shows my sight glass fitting. While barely resembling a Detroit I at least managed a Detriot like oil cock...It is a hybrid of a commercial unit that turned out to be poorly made in the needle valve area. I used the glasses and the top fittings. In practice, I'm not sure what happens to the glycerine- it certainly diminishes gradually. I suspect some adheres to and passes on with the oil. Over consecutive days the oil gathers in the top of the glass indicating that the volume of glycerine has diminished. Julian suggested to me that the glycerine was being drawn back into the oil tank. Certainly that is possible if care to close valves at the end of run is not carefully followed. However, I now believe some glycerine goes with the oil. I saw a pic - I think Julian's Linda cab - where it appeared the same may have been happening there. They are fun. And reliable. I would not say they are easy to make or even suggest they are less work than a mechanical. Depends on your mechanical - my standard mechanical version has only 2 pieces for the pump body and only turned parts for the ratchet pawls. Of 10 made in a batch in the 1980's, only one has given trouble.  |
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jma1009
Elder Statesman
Posts: 5,900
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Post by jma1009 on Sept 3, 2014 18:48:13 GMT
hi ross,
those sight feeds are very nice! as are the safety valves you posted on the 'scale' boiler fittings thread.
Ed mentioned looking at mechanical lubricator tanks to check that the oil level was going down ok , but ive found that with a long queue of punters waiting for rides you dont have time to check these things when perhaps you should, and so the sight feed arrangement has a lot to recommend for itself.
here's hoping i might persuade Ed to fit a hydrostatic sight feed lubricator to his 7.25"g Manning Wardle JUBILEE!
cheers,
julian
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Post by suctionhose on Sept 3, 2014 21:36:04 GMT
Yes Ed should really do that!
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Post by Deleted on Sept 4, 2014 0:04:27 GMT
Hi Julian, I love that backhead with all the clutter and feel of a full size locomotive. That all makes sense to me now. I presume the valve operated by the regulator is in between the steam valve you mentioned and the bottom of the oil tank. I can see that 1501 has a similar mechanism for operating a valve like that. Hi ROGER--------- that's known as the JOCKEY VALVE ------------ www.thesaintproject.co.uk/Pages/ArchiveNews2012.html |
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Post by suctionhose on Sept 4, 2014 3:53:53 GMT
A lot about it on this earlier thread modeleng.proboards.com/thread/7054The fundamental difference between model and FS hydrostatics is that models use boiler pressure to force the oil out of the tank, thru the glass and down to the cylinders. FS lubricators are under equal pressure (boiler) and the oil is forced out by the head of condensate that accumulates in the top of the lubricator. Once thru the nozzle the oil floats into a chamber where it is collected by a continuous flow of steam directed along a pipe (s) to the cylinders and valves. These days there appears to be a lot of confusion and crossed terminology calling what is a displacement lubricator a hydrostatic. They are certainly similarities but they are not the same. |
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pault
Elder Statesman
Posts: 1,496
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Post by pault on Sept 4, 2014 7:18:32 GMT
As a point of interest there is no reason why you cant have a sight glass in the feed from a mechanical lubricator, some of the Romney locos have them built onto the side of the lubricators.
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Post by ejparrott on Sept 4, 2014 8:25:30 GMT
I'll think about it....
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Post by Deleted on Sept 4, 2014 21:31:52 GMT
As a point of interest there is no reason why you cant have a sight glass in the feed from a mechanical lubricator, some of the Romney locos have them built onto the side of the lubricators. ------------ when I raced Motorcycle Grass-Track ( and a dabble at Speedway) both the JAP and ESO JAWA engines employed a Pilgrim pump with two small "windows" such that you could regulate the oil flow ie}---- Fully open for big-end and 2-3 drips per min. at fast idle for the rocker train............The whole system utilised the "Total Loss" principle.... |
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I would really, really love to have hydro-static lubrication on 4472...alas if strictly following the prototype I can't....
