Author Topic: Ateliers Engine Build  (Read 8195 times)

Offline ChuckKey

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Re: Ateliers Engine Build
« Reply #15 on: January 22, 2017, 12:13:26 AM »
It looks as though it is a Meyer expansion valve, but this is the first time I have seen one apparently controlled by the governor; they are usually adjusted manually. I love the fan-shaped thing on top of each expansion valve rod end, which I take to be a scale for a cut-off indicating pointer.

Offline steamer

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Re: Ateliers Engine Build
« Reply #16 on: January 22, 2017, 12:36:58 AM »
Yes but I'm trying to wrap my head around the mechanism that controls the riding cut off governor......hmmmmmmm

Dave
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Damned ijjit!

Online Jasonb

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Re: Ateliers Engine Build
« Reply #17 on: January 22, 2017, 08:29:02 AM »
Looks like the shaft from the governor goes into a set of bevel gears (u) and rotates the valve rod, if the two pucks on the rod are L/H and R/H threaded then as the valve rod rotated that will move them to cover or uncover more of the valve below.

A similar thread on teh fan shaped dial pointer would let you see the movement of the pucks

Offline ChuckKey

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Re: Ateliers Engine Build
« Reply #18 on: January 22, 2017, 10:03:43 AM »
... if the two pucks on the rod are L/H and R/H threaded then as the valve rod rotated that will move them to cover or uncover more of the valve below.

Yes, that is how a Meyer valve works. In playing around with the design of one some years ago, I found that I could more accurately match valve events over a wide range of cut-offs by using slightly different pitches for the two threads. I have two textbooks that discuss the gear in some detail, and neither mentions this possibility.

In this case I too am unclear how the movement of the governor causes the bevels to rotate. In any case I am unconviced as to how well it would have worked: one of the things to avoid in governor gear is friction, and this arrangement would have a lot of that.

Online Jasonb

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Re: Ateliers Engine Build
« Reply #19 on: January 22, 2017, 10:26:38 AM »
It may be that the two bevels on the governor shaft are mounted on a helix so as the balls make the shaft go up and down the two smaller wheels rotate on the helix and then rotate the larger gears, this would only be a relatively small movement of the gears probably not even a full rotation so you would need quite  a fast spiral on the valve rod too.

Offline steamer

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Re: Ateliers Engine Build
« Reply #20 on: January 22, 2017, 04:15:55 PM »
Yeah but whats confusing is the upper right hand view...which I assume is the governor mechanism...and then the general view with the bevel gears.

the shaft has a bevel gear on the valve spindle...implying it's part of the riding cut off mechanism....but look at the other end ...it's on a radial link joint...which means the shaft can't rotate.....we're missing something.....

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Rivergypsy

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Re: Ateliers Engine Build
« Reply #21 on: January 23, 2017, 01:04:23 PM »
Wow, some beautiful engines in the scans, and amazing draughtsmanship too - I can't believe this has just come to light after searching for so long.

In terms of the cut-off, hopefully with a little more modelling it'll be possible to turn the engine over and see quite how the it works at different governor positions. Here's a link to an early animation of the engine from late last year -

Many thanks again all for your help, input and enthusiasm!

Dave

Offline kvom

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Re: Ateliers Engine Build
« Reply #22 on: January 23, 2017, 03:18:56 PM »
Looking at the vertical view of the two valve rods it appears that they are separated laterally by 336mm as opposed to being one on top of the other in your model.

Online Jasonb

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Re: Ateliers Engine Build
« Reply #23 on: January 23, 2017, 03:57:22 PM »
They look to both be in line and on the ctr line of the cylinder from above

Offline kvom

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Re: Ateliers Engine Build
« Reply #24 on: January 23, 2017, 04:25:27 PM »
Seems there must be some sort of offset in the rod between one end and the other.

Online Jasonb

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Re: Ateliers Engine Build
« Reply #25 on: January 23, 2017, 04:30:26 PM »
Which bit of which drawing are you seeing an offset in?

J

Offline kvom

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Re: Ateliers Engine Build
« Reply #26 on: January 23, 2017, 05:42:44 PM »
My mistake.  I thought that the cam bracket was the upper rod, which is in fact not seen in this view.   :noidea:

Offline gerritv

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Re: Ateliers Engine Build
« Reply #27 on: January 23, 2017, 10:08:00 PM »
Drooling over those engravings and the complexity of the machine.
One of you might be interested in https://www.abebooks.com/servlet/SearchResults?kn=delaby&sortby=17&tn=MACHINES+%C0+VAPEUR+

Gerrit
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Offline Rivergypsy

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Re: Ateliers Engine Build
« Reply #28 on: January 25, 2017, 12:31:15 PM »
LOL, the drawing does take some digging through, doesn't it? That cut-off had us head-scratching for a while, as did the rear support bearing, although it has to be said i did ponder the option of mirroring the engine to put another two cylinders on the other side of the flywheel... :naughty:

Offline Rivergypsy

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Re: Ateliers Engine Build
« Reply #29 on: January 25, 2017, 12:36:17 PM »
Btw, thanks for the book links - now on order from Amazon!  :happyreader: