Author Topic: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler  (Read 5240 times)

Offline Inky Engines

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Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« on: February 28, 2013, 10:24:15 AM »
The video shows my recently completed steam plant based on Elmerís VR75 in action.  The boiler is substantially to Sandy Campbellís design, as recently posted on the MEM Plans and Drawings board, Iíve just modified the base slightly.  The plant includes exhaust steam oil separation, and has manually pumped and pre-heated feed water delivery. 

The oil separator appears to work well, in that there is water in the displacement lubricator, and oil in the exhaust condensate pumped from the separator.   The sharp eyed may notice that Iíve changed the displacement lubricator - I increased the capacity, and added a flow control valve.

I added the feed water preheater (comprising a 15Ē long copper tube coiled inside the oil separator) purely as an experiment; it heats the feed water from ambient temperature to near boiling point, but I have no idea as to what, if any effect it has on overall efficiency. 

Iím presently using the 1Ē ceramic burner with No 5 gas nozzle from my 2Ē boiler, but the base would take a 2Ē diameter burner with larger nozzle.  The safety valve is to a design by Gordon Smith modified slightly to account for the lower operating pressure.  The safety is set at 45psi, but the engine does not need this sort of pressure, it will happily run on less than 10psi.

The feed pump is an off the shelf purchase.  Iím presently building Elmerís Vauxhall Donkey Pump, and wondering if this might be suitable to feed water to this boiler?

I hope you enjoy the video!- its not quite the first run - there were far to many loose connections and joints for this to be posted!

As always comment and questions welcome.



<a href="http://www.youtube.com/watch?v=mdvk5ekM-0s" target="_blank">http://www.youtube.com/watch?v=mdvk5ekM-0s</a>

Kind regards

Geoff at Inky Engines

Online Jim Nic

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #1 on: February 28, 2013, 11:04:00 AM »
A superb plant Geoff, well done.  :ThumbsUp:  Watching it run has reinforced my ambition to add Sandy's boiler to my project list and if I can produce a plant half as good as yours I'll be well chuffed.

Jim
The person who never made a mistake never made anything.

Bogstandard

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #2 on: February 28, 2013, 11:25:48 AM »
Very nice plant indeed Geoff. :praise2:

Just a couple of mods you should try to make it even better.

Do go for the larger burner, you should be able to turn it down a lot and still get up to full steam in very little time.

When I was producing engines for sale, I always used to advocate the use of two steam control valves, the first where yours is, on top of the boiler, but if you put another one in the steam line to the engine, and lock it up at the optimum running speed of the engine, then you can just turn the one on top of the boiler off so that you can top up your inline lubricator plus any other other little tweaks that need to be done without losing the settings the engine requires. You should find that by doing this, you should not need as much steam to be produced to keep the engine running smoothly. When fitted into a working model, the engine should only be running at a couple or few hundred RPM at most

When you see people operating these little engines, especially oscillators, invariably they are putting too much steam through the engine and you see steam blowing from everywhere, that is a totally inefficient way to run a steam engine. If the locked up valve is set correctly, you will get optimum efficiency from the engine without losing any of the precious steam.

Nice one

John

Offline b.lindsey

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #3 on: February 28, 2013, 11:54:23 AM »
Very nice Geoff. Great job on the video too but yours always are :).  So how long can you run it safely before having to use the feedwater pump to add more water to the boiler. ALso what is the reason for running the exhaust steam through the chimney?  Is it to imporve drast as in a locomotive or just a convenient way to direct the exhaust steam upwards rather than out to the side for example?

Bill

Offline zeeprogrammer

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #4 on: February 28, 2013, 12:10:53 PM »
Beautiful plant Geoff.

That, along with a couple of tips I see from Bogs, is going to be useful in my next project.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Zee-Another Thread Trasher.

Offline SandCam

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #5 on: February 28, 2013, 06:00:48 PM »
 :stir: :slap:... I don't remember saying you could modify my boiler >:D :ThumbsUp: :LittleDevil:

Quote
Iíve just modified the base slightly
:Jester:

Well now... I would hate to think what a major mod would be :lolb: :ROFL:

Just kidding Geoff, It's nice to see someone else using the design, which is what it was posted for.

What a lovely job you have made of that plant, I particularly like the addition of a feed water heater, you should find that this will reduce your gas consumption considerably and will help reduce pressure sag when you come to refill via the hand pump since the feed water will already be at a much higher temperature.

Did you shorten the main barrel or, as I suspect, lower the bottom tube plate to give a larger water content? and possibly with the addition a further cross tube or two in the main flu.
I assume you can slide a 2" burner through the gap in the new bottom assembly?

Elmerís Vauxhall Donkey Pump should be more than adequate as a feed pump so long as you can control it's run time adequately or it will overfill your boiler.

I look forward to seeing how you get on with it when you get it finished.

Best regards.

Sandy. :cheers:

Offline Don1966

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #6 on: March 01, 2013, 02:07:23 AM »
Beautifully done Geoff, love the way it looks the cladding adds to it also.

Don

Offline Inky Engines

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #7 on: March 01, 2013, 08:58:41 AM »
John...

I've seen your advice on running these small engines before, and certainly got better performance from my Fancy wobbler when I throttled back the steam.  Both your suggestions are now on my to do list, I had always intended to fit a 2" ceramic diameter burner (possibly) to Sandy Campbell's design, and the base is designed for one to slot straight in.  Thanks very much for your very helpful input.

Bill...

I had no idea how long it would run before needing more water,  it had never really been run under anything like stable conditions ... and so I checked .... at moderate revs it will run for about 15 - 20 minutes during the time that water is seen within the visible 2" of the water gauge.  It would probably be longer if run at the speed recommended by Bogs.

As to the reason for the exhaust being fed through the chimney, I wanted to get the exhaust away vertically from the top of the model and had a choice between doing so within. or outside the chimney.  I hoped feeing through the chimney would improve the draught, although I do appreciate that this is more appropriate in a coal fired unit.  I was concerned that condensate released on start up above the burner may be a problem, but this seems not to be the case with the in line oil separator.

Sandy...

What can I say, I hope I haven't breached any terms and conditions of use, I'm just pleased I didn't build the boiler twice size!

Seriously, thank you for making the design available - I would certainly recommend it to others, it is straightforward and logical to build, and I have been nothing but impressed with the performance.

I used a 5 1/2" length of 3" diameter copper tube - the barrel is therefor 1/2" shorter than design, the bottom flange is inset 1/2" in the barrel so that the roof and upper sides of the firebox are copper, and there is 1/2" of extra internal height.  Unfortunately, I didn't think out the use of the extra volume too well and it sits at the top of the boiler with all the fittings at design height - it would have been better within the water gauge height, or possibly below the water gauge as an extra safety factor.

Jim, Carl, Don...

Thank you.

Kind regards

Geoff from Inky Engines




Offline SandCam

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #8 on: March 01, 2013, 01:44:42 PM »
Hi Geoff,

Quote
I hope I haven't breached any terms and conditions of use

As far as I am concerned You have broken every rule in the book, in fact you can expect a visit from an official of the British Boiler Bashers Association who will confiscate all your engines and boilers >:D :censored:... you have not broken any rules... quite the opposite... you have taken a basic design and adapted it to your requirements without compromising the design integrity of the pressure vessel.

The only things I am concerned about are: -

1/ I DID NOT THINK OF IT!!! :facepalm: :Doh: :Lol: :ROFL: :lolb:

2/ You got my Initials wrong in the credits of your video  :'(:( :naughty: :stir: It's A. F... Not A. J.
    But I am sure my Son Alex James will be happy to accept the credit  :whoohoo: :Jester:

Seriously though, the only time I would get concerned would be if someone were to use one of my designs for commercial purposes without my consent and/or, worse still, changed something that compromised the design integrity of the pressure vessel (such as reducing the thickness of the boiler shell or flu to make it cheaper) and also attributed the design to me.

Nothing you have done has made any difference to the original design spec.  You have, in fact, improved it as far as access to the burner is concerned. Very well thought out.  :praise2: :ThumbsUp:

As for the extra 1/2" of volume... it's arguable where this would best be used... certainly below the water gauge would have merit in providing a little more safety, with respect to low water level, however, having it at the top, as you have done, can also be of great value, since it increases the steam space above the water and thus will reduce the risk of carry over of water when the boiler content is at maximum on the water gauge.

With your addition of a hand feed pump (and soon to be a steam pump) the low water situation is better guarded against so, on merit,  I feel that having it at the top is possibly the best use in your particular setup... this will be more evident when/if you change to a larger 2" burner.

Which ever water feed pump you finally end up with, remember, it is always better to feed replacement water in small amounts, rather than wait for the level to drop to almost the bottom of the glass.
By adding smaller amounts, more frequently, you avoid large temperature shift within the boiler (along with the associated large pressure drop) which would occur when you add a lot at once.

Finally Geoff, I concur with John regarding the second preset/locked steam valve as it makes servicing whilst in steam so much easier to manage.

Keep up the great work.

Best regards.

Sandy. ;D :cheers:


Bogstandard

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #9 on: March 01, 2013, 02:55:28 PM »
Just to add to what Sandy has stated.

Over the years, I have seen many efforts by people to try to extend steaming time.

Some people seem to think that you can steam forever just by adding a pump or two. It can be done, but the engine would also have to have some sort of continuous lubrication as well.

What you should really be aiming for is to have the boiler, as Sandy has stated, topped up with a few drops rather than a continuous stream, and the final effect should be to maybe double your steaming time, from say 20 - 25 minutes to say 3/4 of an hour. After that time, the engine will most probably be requiring a good lube anyway, and it would give your gas tank time to warm up again as well.

Your idea of putting the feed water through the oil/water trap in not new, but very few people do it. But also, if you made yourself a rechargeable gas tank, you could sit it in a bath of water, also fed by the exhaust steam pipe running through it, that would keep your gas pressure much more stable throughout the steaming time as the gas tank wouldn't frost up as quickly.

John

Offline Inky Engines

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #10 on: March 02, 2013, 08:50:16 PM »
Sandy & John

Thank you both for your further input, clearly further examples of the expert advice and support available on the forum, and so generously given to newcomers to the hobby.  You have given me much to think about. .... I had thought the project was complete!

Sandy

Sorry about the typo in the You Tube video credits  - as you will know I can't edit it and to repost the video would break the existing links.  I have however put the correct middle initial in a credit in the video description.  You Tube audience retention analysis shows that only 50% watch the credits anyway, most of the others give up after the movie bit, a few give up during the still image introduction (perhaps they don't like Star Wars) - my point is that it's possibly better in the description than at the end of the video - no excuse but it makes me feel better.
 
Kind regards

Geoff at Inky Engines

Offline gary.a.ayres

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Re: Elmer's VR75 Engine & Sandy Campbell's 3" Steam Boiler
« Reply #11 on: November 11, 2019, 01:18:17 PM »
The video of your plant here has been an inspiration to me over time, and remains so as I continue with my own humble efforts.

 :LittleAngel: