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Post by tecnamflyer on Feb 12, 2012 12:38:54 GMT
Gents,
For the uninitiated and seeing it mentioned many times in recent threads,
What is a Hydrostatic lubricator.
Paul
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cotswold
Part of the e-furniture
Still testing the water
Posts: 307
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Post by cotswold on Feb 12, 2012 12:57:44 GMT
Imagine a container containing both oil and water. The oil, of course, is floating on top of the water. Connect the bottom of the container to a steam supply and connect the top of the container via a needle valve to the loco cylinders. If the rate of flow of the oil is extremely low, the steam will have condensed to water long ago (hence the water in the bottom of the container). The only remaining problem is measuring the rate of flow of the oil. So, between the needle valve and the cylinder interpose a vertical sight glass filled with water (or glycerine or whatever). With the needle valve just cracked open, drops of oil will float very slowly up through the sight glass, one by one. You now have avisual indication of the rate at which oil is passed to the cylinders.
No moving parts and extremely simple in use (not quite so simple to make and I have to admit that mine is bought).
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Feb 12, 2012 13:50:30 GMT
A picture paints a thousand words - even if it is not a good picture!  With Cotswold's explanation, you should be able to see how it works. Just to take it a little further, the GWR used it on 0-6-0 tanks - possibly other locos. If you leave the oil on whilst the engine is idle it carries on pumping oil. Therefore, there is a valve operated by the regulator handle to shut the oil off when the loco is idle, as in this picture of 5764 at Bridgnorth, SVR. The big red handle is the regulator and the other red item is part of the shut-off mechanism to the oil supply valve, which is at the bottom of the picture (just about). ![]() www.tonykendall.co.uk/images/5764 018Small.jpg[/img] |
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Post by RGR 60130 on Feb 12, 2012 16:17:10 GMT
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Post by peterseager on Feb 12, 2012 18:14:30 GMT
Hydrostatic lubricators were the GWR lubricator of choice until relatively late in the GWR's existence. The Southern also used them, the Schools for certain.
My Manor does not have the regulator valve ie its just like the diagram above. Works fine. For a short stop I don't do anything but for a longer stop eg lunch, just turn the steam valve off.
The Simplex won't have the sight glass. The tank is behind the front buffer beam and feeds straight to the cylinders through a needle valve. The chimney is then used as an indicator of satisfactory lubrication. With the sight glass I find the chimney is still important as a check. Several people have reported that this simplified system works. This setup has the advantage that the steam pipe, which needs to be long, is long and the oil pipe is short, again what is needed.
The tank holds more than enough oil for a days running therefore missing out the sight glass is not a problem.
Peter
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Feb 13, 2012 11:17:27 GMT
despite having at least a dozen ratchet wheels pump parts and bits for quite a few mechanical lubricators, all my current locos are fitted with 'hydrostatic' lubricators which i have made myself, and i wouldnt go back to mechanical lubricators.
strictly speaking our 'hydrostatic' lubricators are simple displacement lubricators with a sight glass and oil control needle valve in the supply line. jack austen-walton described one for his 'TWIN SISTERS' in the late 50's, and fred cottam described a rather complicated arrangement for his 3.5"g GWR KING. the cottam arrangement was then used by martin evans for TORQUAY MANOR. Roy Amesbury published a design for his PRESIDENT loco. don young specified hydrostatic lubricators for most of his later loco designs but only published the details for one loco GEORGE and even then was careful not to disclose all the secrets as he relied on selling completed fittings commercially!
they have the big advantage over mechanical lubricators of not needing check valves or any working parts that wear out, and i have always found them easy to make and operate with 100% success. there is no more work involved in making the sight glass than a water gauge IMHO. the sight glass can actually be made quite small (unlike some early commercial and published designs).
i was told the missing 'secrets' of the don young design. if you look at the TORQUAY MANOR drawings you can be easily put off i think, and i have found it unneccesary to incorporate any check valves or an atomiser (incidentally the fullsize pic above from tonytrans of the GWR arrangement shows the atomiser valve that the oil stop valve incorporates). i have built 2 hydrostatic lubricators for GWR locos with the correct regulator quadrant linkeage but connected to a simply stop valve rather than an atomising valve.
i dont know why some people have problems with the sight glass filling with oil...in theory this shouldnt happen! the sight glass can have 'O' rings on the end of the glass if the ends are ground smooth, or around the glass if not but either way a register needs to be made in the body to stop the 'O' rings being displaced by the pressure within...ive seen quite a few commercial sight feeds without this provision! make sure you use 'O' rings suitable for cylinder oil.
the pipework needs to be small in diameter and bore...i use 3/32" dia rather than tonytrans' 1/8" dia. also at the steam chest end there should be a 'choke' in the pipe... the connecting nipple drilled say 1mm for its length will suffice. the 'jet/nozzle' at the bottom of the sight glass for the oil to blob up the glass from needs to be drilled as small as you can get it say No. 76 or preferrably No. 78. in my sight glasses the needle valve seat is the bottom of the 'jet/nozzle' fitting. my needle valves are 10BA with quite a long taper.
the whole assembly and your oil can and its contents need to be kept scrupulously clean!
in operation they work reliably and feed far less oil than a mechanical pump, and not only is it fun to see them work and provides an additional feature in the cab but you know it is working! you need to have a bit of a routine for emptying and filling the tank, and remember to open the steam valve before leaving the steaming bay, and closing same at the end of a steam up, so if you are a bit absent minded or get into a flap running a miniature loco then they are probably not for you!
the fittings and tank and pipework etc needs careful silver soldering and cleaning afterwards to remove any flux and muck that might block the pipes or jet/nozzle, and of course the whole system and especially the tank must be pressure tested hydraulically after making. there are quite a few miniature locos where the mechanically lubricator is difficult to fit or drive, and where a hydrostatic lubricator can be usefully substituted. and as commented on above if it's a GWR or a Southern loco (with a few exceptions) it ought to have one anyway!
i have used both the more refined light and heavy grades of steam oil in hydrostaic lubricators with no difference in their operation.
i use Roy Amesbury's method of glycerine in the sight glass.
as i wear glasses i dont like to get splattered with oil when im driving!
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Feb 13, 2012 11:34:02 GMT
not the best pic im afraid, but you can just see bottom left corner the sight feed glass, top left is the small steam valve for the oil tank, and centre the simple plug on/off valve connected to the regulator quadrant. the oil tank is underneath the cab floor so cant be seen. Attachments:
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Post by peterseager on Feb 13, 2012 18:23:45 GMT
I believe there are two types of lubricator we are discussing here:
Hydrostatic lubricators where steam from the manifold is condensed and forces oil into the cylinder. Our miniature systems don't essentially differ from full-size except for some simplification. Fred Cottam's design is very much like the GWR system.
Displacement lubricators where there is a direct connection between the valve chest and oil tank and steam miraculously gets from the valve chest and into the oil tank displacing oil back to the cylinders down the same pipe. Shawki Shelmon uses this system and discussed it in one of his threads. The ultimate simple system. Shawki essentially uses a separate tank for each cylinder. I wonder if this is the reason it works so well because the steam will be pulsing more than if a single tank was connected to a common point between the two cylinders. This is why I decided to go down the hydrostatic route when retrofitting my Simplex.
Peter
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waggy
Statesman
Posts: 744
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Post by waggy on Feb 13, 2012 19:36:37 GMT
Shawki,
Could you post a schematic of this dark art?
Waggy.
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Post by peterseager on Feb 14, 2012 8:59:33 GMT
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waggy
Statesman
Posts: 744
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Post by waggy on Feb 14, 2012 9:12:22 GMT
Thanks, Peter.
Did look but searching the forum isn't that easy.
Waggy.
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Feb 14, 2012 10:09:10 GMT
i remember reading sometime ago in ME that our 'hydrostatic' lubricators were not strictly speaking 'hydrostatic' as per fullsize. i cant remember now what the distinction was...i think it was in one of the late Basil Palmer's articles so will have to dig it out and refresh my memory!
one further tip i would recommend is to paint the back of the sight feed glass (on the outside!) with white enamel. no point having a sight glass if you cant see what's going on inside it!
as a bit of an aside and going back to mechanical lubricators of the LBSC oscillating type i dont like the idea of the pump not pumping for over half the time it takes for the ratchet wheel to do a full circle, and if the linkeage is connected to the valve rod there might be quite a long time between squirts of oil if the loco is notched up and just moving the ratchet wheel (or roller clutch assembly) just a small amount each revolution of the wheels. i would rather have a constant feed irrespective of the loco being notched up with the ratchet wheel going round say 3 teeth per revolution of the wheel, and reduce the bore of the ram. i fitted a mechanical lubricator to my first loco and sleeved the pump bore down from 1/8" to 1/16" and fitted a 1/16" ram, and the pump was worked off the axlepump eccentric. ive never understood why mechanical lubricators are often connected to the valve gear.... surely a loco needs the same amount of cylinder oil when working notched up as in fullgear?!
of course hydrostatic lubricators avoid all these problems!
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Post by Boadicea on Feb 14, 2012 13:23:57 GMT
of course hydrostatic lubricators avoid all these problems! Alternative view.... Fit a Jim Ewins type mechanical oiler, set the flow by adjusting the spacer, forget about it except for topping up. No messing with sight glass, glycerine, constantly adjusting, over-oiling at idle. Apologies, unable to write more!  ;D |
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Post by peterseager on Feb 14, 2012 18:07:59 GMT
Just looked up Hydrostatic lubrication on Wikipedia: So the Hydrostatic lubricators used on full size locos are no different to our size. Someone obviously borrowed the term a long time ago and applied it to loco lubricators. The sense of applying pressure to the lubricant is certainly there but it only provides a supply of oil to the bearing surfaces. [Edit] Another reference on the web dates the invention of hydrostatic lubricators back to 1870. The accompanying drawing shows two chambers for oil and water, connected at the bottom. From this you get a sense of water and oil balancing and pushing the oil out. From this it would appear the word hydrostatic was invented without thought of any other use. See: www33.brinkster.com/iiiii/mccoy/Peter |
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Post by steamjohn248 on Feb 15, 2012 22:47:31 GMT
I'm with Boadicea, Jim Ewins Pumps are foolproof especially if driven by roller clutch, if you do not want the bother of making them they are available "off the shelf" in a range of delivery amounts, as used on commercial vehicles for automatic chassis oiling. Google "Interlube". Units are available from,among others, www.Woodwardssvsltd.co.uk Usual disclaimer. we use them on all our locos and steam launch. Steamjohn |
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Post by peterseager on Feb 18, 2012 18:54:32 GMT
I found Basil Palmer's article mentioned above, Model Engineer, 18th October 1991. He describes how he made a Detroit Hydrostatic Lubricator for a South African Class 16E loco. A similar lubricator was fitted to the Schools Class. Basil states there is "A difference between a displacement and hydrostatic lubricator" but does not elaborate further. He continues by describing the Detroit Hydrostatic Lubricator. "If reference is made to the sketch illustrating the principle of the Hydrostatic lubricator, it will be clear that while the oil is displaced from the oil reservoir by the condensed steam, its subsequent progress to the cylinders is not governed or determined in rate of flow or volume by the boiler pressure or quantity of steam available, but only by the head of condensed water above the oil in the reservoir and the opening controlled by the driver/fireman in the screw valve under the sight glass." He goes on to discuss how gravity would be sufficient to get the oil to the cylinders and the need for the pipes to fall from the cab to the cylinders. Steam to the oil pipes is needed so that the oil will gain entry to the cylinder which is under varying pressure itself with the opening and closing of the regulator. So there is a difference between the lubricator used on models and shown in the diagram at the head of this thread and full-size lubricators in that the miniature version uses steam to force the oil through the metering device and on to the cylinder but full-size relies on a fixed head of water in the lubricator to meter the oil and steam helped by gravity to take the oil to the cylinder. Peter Attachments:
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Feb 18, 2012 20:53:39 GMT
G'day Peter
Thanks for that diagram; it is the first time I have seen that arrangement particularly the choke mixing live steam and oil after the sight glass. The oil reservoir is still at boiler pressure but there is carrier steam to the cylinders. Is the live steam supplied from the turret 9manifold) or from the steam pipe after the regulator?
I model form I wonder if you could get enough head to lift the oil without making the lubricator well out of scale?
Regards
Ian
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Post by fostergp6nhp on Feb 18, 2012 22:18:12 GMT
On GWR the carrier steam and steam supply to the resevoir via the condensing coil is controled by the valve under the regulator handle which is also the atomiser(choke)
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Post by Deleted on Feb 18, 2012 22:55:07 GMT
On GWR the ........ steam supply to the resevoir via the condensing coil is controled by the valve under the regulator handle which is also the atomiser(choke) Not so, the steam supply to the condenser coil comes directly from the fountain on top of the boiler. Sorry! |
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Post by Shawki Shlemon on Feb 19, 2012 8:33:10 GMT
Someone up there is asking me to post a diagram of a simple lubricator , I have changed my computer to Mac and I don't know my way around it but I will try to explain it . I use one per tank and that way I know if all cylinders are getting oil .
The tank , I use a copper pipe around 1.25" diameter ,closed at both ends with copper or bronze ends ( silver soldered ) , three fittings one on the top which includes a jet ( I start with no 75 drill ) , lately I have been making the jet removable for adjustments ( I have in some cased fitted the jet in valve chest wall instead of the tank ( it makes no difference other than accessibility ) , I use 1/8 pipes . At the bottom I fit two fittings one with a stand pipe inside , call it vent and the other one drain and filler . The top fitting is connected to the valve chest ( that is it one connection ) To drain the water I open both bottom fittings , water will flow out , when oil start draining , I stop connect an steam oil can and pump oil until it flows from the vent fitting , plug up and is done . Of course there will be a bracket to fit the lubricator .
My latest engine NSW C32 was not oiling well , I increased the jet hole s to one size up and tested the engine Today , oiling was fine , I am very happy with it .
I hope this helps
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;D
