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Detroit Hydrostatic Lubricator

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David Smith 4815/02/2019 02:11:31
10 forum posts
3 photos

Does anyone have a set of drawings that I could get copies of that were offered for the asking by Basil Palmer for his 1.5" scale Detroit Lubricator described in the 18-31 October 1991 issue of Model Engineer?

Thanks for reading, Dave

David Smith 4827/03/2022 00:36:10
10 forum posts
3 photos

Further to my question two years ago, along with other projects, I'm still tinkering with a single feed version of the Detroit lubricator. Does anyone have experience with the practical smallest inside diameter of the sight glass that still provides reliable drip feed? So far all of the designs I have found call for 12mm O.D. (.470" and 1mm to 2mm wall thickness. I'm wondering if .375" O.D. with .047 wall thickness can be used?

Thanks for reading, Dae

Dave Wootton27/03/2022 06:06:33
317 forum posts
66 photos

Hi Dave

I've used the 12mm od sight glass with sucess ( the glass available pre cut from Reeves) in the standard sight glass lubricator. And I have seen a twin feed set up using 3/8" gauge glass tube working very well on a 7 1/4" Jessie. I intend to make one for my current loco using 3/8" glass.

On the Model engineer clearing house forum Malcolm Brown describes the construction of a very neat Detroit lubricator in the thread " 99 3462 Build diary" there is also much information on thereregarding these lubricators and a reprinted article by Julan Atkins regarding construction and jet sizes etc I followed these for mine.

I have not got the articles but Roy Amsbury used smaller than usual sight glass in the design of his lubricator in M.E . Having got a sight feed on a small 3 1/2" g engine that bounces around a bit on the track, I would imagine that one of the limiting factors with regard to glass size would be the oil droplet hitting the glass wall, probably not such a problem with a larger more stable engine driven sensibly!

Dave

Dave Wootton27/03/2022 08:54:06
317 forum posts
66 photos

Got it wrong about Malcolm Brown's Detroit lubricator, Its on M.E.C.H but only mentioned in a thread with a picture  " Hydrostatic lubricator article" and is fitted to his Burma Mines locomotive. A very neat design resembling a Detroit lubricator.

Dave

Worth reading Malcolm's build thread a master of fabrications that look like castings, I pinch lots of his ideas.

Edited By Dave Wootton on 27/03/2022 08:56:22

David Smith 4828/03/2022 00:46:53
10 forum posts
3 photos

Hello Dave, Thank you for taking the time to reply to my query.

Your response makes me think the inside diameter of the glass tube is almost solely driven be what is necessary to prevent the oil droplet from hitting the wall. From my own experiments using a 1/64" nozzle diameter the oil droplet is about 3/32" diameter just before it leaves the nozzle in a 50% solution of glycerin and water. For a 3/8" diameter glass what wall thickness will you use? The only 3/8" diameter glass I can find has a .079" wall leaving the inside diameter of only .220". However, I can easily find 100mm (.394" diameter glass with 1mm and 1.5mm wall giving I.D.s of .316" and .276" respectively. Then the question is how thick does the wall have to be?

I would love to get copies of the articles by Malcom Brown, Julian Atkins, and Roy Amsbury as you suggest. However, I'm writing from the USA and don't know how.

Dave

Dave Wootton28/03/2022 07:07:54
317 forum posts
66 photos

Hi Dave

The Julian Atkins article , originally published in a club magazine,is available on the Model Engineering Clearing House Proboards website forum, as is the picture and mention of Malcolm Browns Detroit style lubricator. I don't know how to post a link but I'm sure a search will find it. It is very similar to this forum but more biased towards locomotive construction. The Roy Amsbury articles are I believe in the build series for his Great Western locomotive President that was featured in Model Engineer magazine in the 1980's, I'm afraid I don't have copies of those. There are several threads on Hydrostatic lubricators on the site.

As regards the thickness of sight glass tube I bought some 10mm o/d glass tube with a wall thickness of just over 1mm, this was being sold as boiler gauge glass tube by a traction engine specialist. As the lubricator pressure cannot exceed boiler pressure I assume it should be ok. I need to make several sight glasses in the near future so I will experiment a little, the ones made previously have been hydraulically tested up to over boiler pressure, mainly to test for leaks, likewise the oil tank has been pressure tested.

The oil jet in the sight glass is drilled no 78 and the oil control valve has a gentle taper which gives good contol, A friend had a commercial sight glass which would not feed consistently, we found the oil jet was much too large at around.030" replacing it with a smaller jet made it perform well. The other important thing which i got from Julians article is a 1mm restrictor where the oil delivery enters the steam chest, this prevents gulping when steam is shut off.

Have a search for the M.E.C.H Proboards site, if you get stuck I'll try to forward a link , I'm not very good with computers! Maybe some kind person who is may post one.

Dave

John Purdy28/03/2022 17:47:45
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360 forum posts
204 photos

Dave

I've sent you a PM.

John

David Smith 4830/03/2022 20:50:17
10 forum posts
3 photos

Hello John,

If you sent me a PM I did not receive it.

Dave

David Smith 4830/03/2022 21:19:47
10 forum posts
3 photos

Hello Dave, Thank you again for taking the time to reply.

The #78 (.016" dia.) drill for the oil jet is encouraging since my tests concluded a 1/64" (.0156" dia.) works well. Thanks for the tip on the 1mm restrictor where the tube enters the steam chest. I have seen restrictors in either the lubricator out let on at the steam chest., some times both. If you have had good luck with just the one at the steam chest that is the method I'll use.

Do you think a 3/32" dia. thin wall tube is big enough from the lubricator to the steam chest? The total distance is abour 40".

I'll try to look up the sources as you suggest. I'm not to good with computers either. When in engineering school we used slide rules.

Apparently your leaning towards 10mm O.D. X 1 mm wall tube. Would that be borosilicate or quartz glass. According to internet sources the quartz glass is more durable.

Next question is sealing method. I've seen O-rings on the glass O.D. trapped in a gland. I've also seen O-rings clamped against the end of the glass tube. Obviously when the O-ring is on the O.D. the glass end treatment is not so critical. I believe the glass end is usually ground square and smooth.

I've tried to send a picture of the back head of my boiler with a drawing of the lubricator taped in position. But, I can't seem to get my file into the "album" so to attach. The Detroit lubricator I'm modeling is not the type in Basil Palmers ME article in 1991. But rather the older design.

You've ben very patient and I'll not pester you any further.

Dave

John Purdy30/03/2022 21:42:46
avatar
360 forum posts
204 photos

Dave

I just checked my sent box and it shows my message as being unread. Have you checked your message inbox? Its the envelope shaped icon in the login line at the top of this page, between "Settings" and "Friends". It should be flashing.

John

John Purdy30/03/2022 22:21:20
avatar
360 forum posts
204 photos

Dave

I've just re-sent my PM.

John

julian atkins30/03/2022 23:55:53
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1258 forum posts
353 photos

Hi Dave,

If you send me a PM with your email I can send you the articles and drawings referred to.

Cheers,

Julian

Dave Wootton31/03/2022 07:09:55
317 forum posts
66 photos

Hi Dave

Not pestering at all, hope I have been of some help, I see Julian has kindly offered to send you the articles and drawings, he knows far more than me about these, I basically followed his instructions!

My Rob Roy is miles away on display in a relatives house ( failed boiler test!) so I can't measure it but I'm sure the oil pipe to the cylinders is 3/32". This is obviously a much shorter run than yours would be, but has worked fine, as the lubricator was a retro fit for a mechanical pump it is not run under the boiler lagging as I have seen advised to keep the oil warm and fluid. The pipe is quite cool to the touch but even thick cylinder oil finds its way through.

The sight glasses I have made so far have all used commercially available tube with pre ground ends, with O rings sealing against the end of the tube. So far I have only experimented with cutting the 10mm glass tube, the most successful method so far was using a Dremel drill with a diamond cutting disc with the tube held gently in an ER collett in the lathe and the Dremel clamped to the toolpost ( I say clamped but it was actually gaffa taped!! ) turning the lathe by hand. The ends were ground on a diamond sharpening stone using a piece of 1" dia steel with a hole bored a light sliding fit for the glass and the end faced off as a guide to facing the end off square. I've not made the sight glass yet so its not been put to the test but seems to have worked ok.

The glass I bought was sold for boiler sight glasses so I presume it is the tougher stuff, fortunately I bought lots of it as took a few attempts to cut it to length.

Do let us know how you get on with your installation, good luck with it.

Dave

David Smith 4803/04/2022 19:52:13
10 forum posts
3 photos

Thank you to everyone who replied. I have received a lot of specific and useful information. I believe I have enough to confidently proceed.

One last thing puzzles me: Except for Basil Palmers design there is no boiler pressure steam applied to the top of the sight glass where the oil droplet floats to the top in any of the other designs. In these cases apparently the oil proceeds to the cylinders via gravity. While the boiler pressure is throttled at the base of the sight glass by the needle valve the valve throttles the oil flow through the the jet orifice. Where as when boiler steam pressure is applied to the top of the sight glass the needle valve regulates oil flow due to density diference between the oil and what clear fluid is in the sight glass. Plus the boiler pressure at the top of the sight glass forces the oil through the tube and through a "choke" then into the steam chest which is always at a lower pressure.

By casual observation no boiler pressure to the top of the sight glass would make oil droplet regulation easier and more consistent. But, boiler pressure to the top of the sight glass would make delivery of the oil to the cylinder more positive. Which is prefered?

Dave

duncan webster03/04/2022 21:26:49
4116 forum posts
66 photos

Without the steam feed and choke the feed rate is dependant on the difference between boiler pressure and steam chest pressure, decreasing as the regulator is opened. This is not how full size did it. With the steam feed from the jockey valve, the feed oil is pushed through by the column of water between the condenser in the cab roof and the bottom of the oil container. This does not depend on regulator opening, hence the name hydro=water and static. I've said before that I'm surprised this works in models as the height of the water column is much reduced, but several model engineers much more skilled than me have said it does.

Edited By duncan webster on 03/04/2022 21:27:31

Dave Wootton03/04/2022 21:36:04
317 forum posts
66 photos

Hi Dave

I've not seen the Basil Palmer articles, so can't comment on that, but in the more usual version the only connection to boiler pressure is the steam feed to the oil tank which condenses to water to displace the oil, which is fed to the cylinders via the sight glass. Rather than gravity I have always believed it is the difference between boiler pressure and steam chest pressure which causes the oil to feed, hence the restrictor in the oil feed to the steam chest to prevent gulping when the regulator is closed and the pressure difference between boiler and steam chest would be greatest. I would have thought that feeding boiler pressure to the top of the sight glass would balance out the pressure across the sight glass and stop it feeding. There are variations in the design I think to the Fred Cottam/ Martin Evans version which use an atomising valve in the oil feed, but I have no experience of that. The simpler system built to the principles in Julian's article works extremely well and feeds very reliably and is easy to regulate.

The only time I have known feed problems with this system was when the oil tank was very close to the boiler and ashpan and failed to condense reliably. This was cleverly cured by the builder without moving the oil tank, he made a spiral coil in the steam feed and soldered it to the back of the cab steps to act as a heat sink, worked perfectly!

Dave

David Smith 4815/04/2022 01:47:08
10 forum posts
3 photos

Thank you for explaining the difference between having boiler steam applied to the top of the sight glass and not. I'm still perplexed as to which is better. I can see advantages and disadvantages to both approaches. I've decided to try both. The Detroit lubricator I'm modeling is older than Bazil's by 40 years. It has a "T" at the top connection to the condenser that directs steam to the top of the sight glasses via a tube. I can easily build the lubricator to feed steam and also plug the feed to close the flow. I've attempted to attach a photo of my boiler back head so the style of the lubricator can be seen. It is just a sketch of the lubricator taped to the back head. But, I'm sure the concept can be seen.

Dave

SillyOldDuffer15/04/2022 08:50:53
Moderator
8875 forum posts
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Posted by David Smith 48 on 30/03/2022 20:50:17:

Hello John,

If you sent me a PM I did not receive it.

Dave

Welcome to the forum Dave. The arrival of a Personal Message is signalled by a flashing envelope in the "My Friends" box top right of the screen, also shown is the number of PMs in the Inbox. To read the message click on the 'Inbox (1 NEW message)' link. Another way is to click 'Inbox' between 'Settings' and 'Friends' in the green banner top left of screen.

newpm.jpg

You don't have to 'Add Friend' to receive or send PMs.

Dave

David Smith 4815/04/2022 22:02:15
10 forum posts
3 photos

I was able to find the M.E.C.H. Proboards site, login, and register. I searched "Hydrostatic Lubricators" and found Julian Atkins' article of 2014. There is a lot of good information there. Thanks for the tip. On Sept. 3, 2014 Julian says, (I quote) ...difference between model and FS (full size) hydrostatics is that models use boiler pressure to force oil out of the tank, thru the glass and down tot he cylinders. FS lubricators are under equal pressure 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 collect by a continuous flow of steam .....to the cylinders and valves." Julian's explanation is excellent. In his narrative the operative words are: 1. For models "..boiler pressure to force the oil..". 2. For FS "...forced out by the head of condensate...". I believe he had the key to the model system. I'E': The "head" in the model lubricator is too small to have enough weight to push the oil through the nozzle of .015" +/-. Thoughts?

I believe it was Dave Wootten who asked me to keep the forum informed on my progress. Well, I have made some progress. In the attached photos are pictures of the lubricator condenser. The first photo is of my 3D print proof. The ball portion is 1" in diameter. I cut it in half to measure the wall thickness as my solid model is used to make the investment casting mold and core. The second photo is of the first test casting. Overall I'm pleased. Although since the efficiency of the condenser is related to the wall thickness I thought it a bit thick. A friend is doing the actual casting and thought he could cast with a little as .045" wall thickness. The solid model has been adjusted and I'm waiting for the next casting. The long tube on the top of the condenser is a chucking piece. Once the hex end is machined and threaded the chucking piece will be cut off and the top machined and tapped for a steam fitting.

I'm also working on the cylinder feed tubes at the steam chests. I hope to have pictures for you soon. If there is an interest?

Dave

duncan webster16/04/2022 00:02:34
4116 forum posts
66 photos

Basil Palmer articles Oct 91 in ME. I've not got a copy. There are some drawings here

Robinson on the GC had a system called 'Intensifore' where he had a pair of chambers in line, one exposed to the steam pipe (I think after after the regulator), one full of oil connected into the cylinders. the steam cylinder was bigger than the oil cylinder, so the oil pressure was always higher than the steam chest pressure, but not as extreme as full boiler pressure. If it is connected after the regulator, then shut regulator = no oil

A slightly more complicated version of this was described in ME quite recently, issue 4639. Probably available via the archive

Edited By duncan webster on 16/04/2022 00:42:51

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