Well Worth A Reading

[rake60]

I happened across a blog by the Science Museum of London
detailing the restoration of tiny 72 year old running
Triple-Expansion Marine Engine Model

Now that is SMALL model engineering!

Rick

 

[rickharris]

Good grief! That shows skills that few would have today. 1/6 stroke - wonder how fast it went when new - maybe he didn't run them.

 

[Divided He ad]

WOW!!!!!


That engine is amazing.... Imagine what else the maker could achive!

Thank you for posting that Rick, it is very interesting.



Ralph.

 

[mklotz]

Not as impressive as the triple expansion engine, but here's an entry for the world's smallest steam powered vehicle...

http://video.aol.com/video-detail/tiny-steam-engine-powered-vehicle/660547713

 

[rangerssteamtoys]

Thats a super small engine
If only the maker diverted his skills to something more useful, maybe he could have build the first mechanical red
blood cell

 

[SandyC]

Hi Guys,

Whilst I fully agree that the model 3 cylinder engine is truly a remarkable example of miniature engineering at it's best, for which the builder can only be highly congratulated, I am,however, at a loss as to why, the science museum have made such a grave mistake in calling it 'A TRIPLE EXPANSION ENGINE'

IT IS NOT..... it is a 3 cylinder in line 'SIMPLE EXPANSION' marine engine.

Take a close look at the intake manifold...it is directly connected to all three cylinders.... this would not be the case for a true Triple Expansion Engine.

In a Triple, the first (HIGH PRESSURE) cylinder would be the only one directly connected to the steam source (in this case air)...the exhaust from this cylinder would then pass directly (often internally) to the valve chest of the second (INTERMEDIATE PRESSURE) cylinder, which in turn would exhaust directly into the final (LOW PRESSURE) cylinder and from there to the exhaust condenser.
A further clue is that each successive cylinder would be much larger than the preceding one...on this model all cylinders are the same dia.

The final clue comes from the statement 'this engine used to run on only the small puff of air obtained from a small rubber bulb'...firstly, such a low pressure air source could not possibly work a true triple expansion engine (even a modern high pressure compressor can have trouble doing this, it is most often just not possible to run multiple expansion engines on air)....on the other hand, such a small air supply could be more than adequate for a 'SIMPLE EXPANSION' engine.

so...sorry MR SCIENCE MUSEUM.... whilst I applaud your very fine efforts at restoring such a remarkable piece of engineering, I cannot say the same for your description of same.

Hope this does not ruin your enjoyment of viewing the video's etc guys....but I felt it only right to highlight the mistake being made.

Best regards .

SandyC

 

[chuck foster]

i have to agree with sandy on this one, it is a simple engine. if you look at the cylinder covers they apear to be all the same size (dia).

i also agree that it is an amazing model and it is even more amazing when you consider it was made in 1936

non the less it is good to see it is being taken care of so we can all enjoy it.

chuck

 

[Divided He ad]

Sandy,

Just a question... did you attempt to highlight this fact on the web page? or by e-mail to the museum?

I would do it myself after reading your post but have no real knowledge of the design of all of these engines yet.(so wouldn't feel right)

I just think it would be nice to notify them so that they have the chance to correct it ;D




Ralph.