Author Topic: Textile Mill Diorama  (Read 112159 times)

Offline J.L.

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The Governor
« Reply #675 on: October 03, 2018, 10:14:45 PM »
Carl, close inspection of my dioramas would mean that almost every member of this  forum would have found something amiss.  ;)

The mounting of the governor proved interesting.  The design of the supporting shape came from drawings loaned to me by Tom. I will have to design the linkage to work the butterfly valve as I go along.


Offline b.lindsey

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Re: Textile Mill Diorama
« Reply #676 on: October 04, 2018, 12:39:51 AM »
I haven't checked in in a few days John as other things have been keeping me busy, but the photos and detail are phenominal as always!!

Bill

Offline steamer

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Re: Textile Mill Diorama
« Reply #677 on: October 04, 2018, 11:11:17 AM »
That's looking great John!

Dave

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

Offline J.L.

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Governor Action
« Reply #678 on: October 04, 2018, 08:19:11 PM »
Thanks Bill and Dave.

Here are some observations about the butterfly valve in the steam tube of the governor body and its function. Jump in and correct me if I am wrong anywhere.

The valve that sits in the tube is set at an angle, so it is not round, but more elliptical in shape. An early Stuart Turner Ltd. Henley-On-Thames drawing indicates that the open position of the valve when installed is at 30 degrees from vertical. Steam shut-off position is at 15 degrees from vertical.

I don’t think this is what I have in these photos. The positions are from horizontal, not vertical. Nevertheless, linkage should make things right.

The first two photos show my positions without the boss. It is effortless to move the shaft. But when an 0-ring is installed and a boss screwed in (photos  3 &4) there is resistance. I’m not sure the weight of the balls will overcome this resistance. The shaft may hang up.  So I am considering wrapping teflon tape in the stuffing box instead. It’s all a matter of preventing air from escaping the valve chest.

If the balls are down and the valve is closed, the engine won’t run. So adjustment of the butterfly valve is critical. I noticed in the notes for a Ransome and May horizontal engine, if really slow running is desired, the governor lever should be weighted to nearly balance the weight of the balls.

You can see this counterweight in photo 5 of a French governor.

Of course all this discussion could be considered academic with a small engine running under virtually no load. It’s just as easy to control speed with a manual adjustment of the steam valve.

If the linkage lets me down, it will be allowed to move freely without operation. After all, the governor is the eye candy of the model.
 
« Last Edit: October 04, 2018, 08:22:28 PM by J.L. »

Offline Admiral_dk

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Re: Textile Mill Diorama
« Reply #679 on: October 04, 2018, 10:03:01 PM »
Wonderful work as usual from you John  :praise2:

I can't remember steam valves - but I have seen a good number of full size gasoline engine throttles and they do not close at 90 degree to the flow, but in the 80-85 degree region (says he without measuring - it might be less).

Offline Steamer5

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Re: Textile Mill Diorama
« Reply #680 on: October 04, 2018, 10:41:03 PM »
Hi John,
 Stunning!
Doing a bit of a catchup, & the additions are just wonderful!

On the governor front, in my view the governor shouldn’t shut off, that’s the job of the steam stop valve. As you rightly point out, if the governor is closed the engine won’t run! My thought is the governor should be a it’s minium stop position (which isn’t closed ) so that it’s throttling the steam flow as the steam is admitted using the stop valve. Once the stop valve is open the governor has control of the machine at min revs, as the load goes on the governor opens allowing more steam in.......just my 2 cents worth.

Cheers Kerrin
Get excited and make something!

Offline J.L.

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AHA!
« Reply #681 on: October 05, 2018, 02:42:54 AM »
Thanks fellows.

Well, tonight the penny finally dropped. I could not get my head around how to get the linkage to operate properly.  As you say Kerrin, as the load comes on, the governor opens allowing more steam in.

Then I descovered my error. I had the throttle valve closing as its shaft was being turned countercloskwise. Turning the shaft clockwise opened it. That's how all the Stuart governors operate. They have levers that push and pull.

I had the throttle valve disk in the wrong way.  :hammerbash: My levers have to rise and fall. Push down and the throttle opens; ease off and the throttle returns to its original position. I simply took the throttle valve out and put it back in the other way.

Good point  Kerrin in stating the job of the steam stop valve as a separate issue. 




« Last Edit: October 05, 2018, 11:03:10 AM by J.L. »

Offline J.L.

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Re: Textile Mill Diorama
« Reply #682 on: October 05, 2018, 12:41:59 PM »
A copule of pictures should simplify what I have said above. In the first photo, the valve has nowhere to go if the shaft is turned counterclockwise. It's locked in the tube at its preset angle. So the balls can't open it when they lose their centrifugal force with a load.

But in photo two, I put the disk in the other way. Now the balls can open the disk as centrifual force is lost with an increased load. In other words, it can open.

I replaced the rather clunky setscrew with a little # 0-80  hex head grub screw. It goes in far enough to lock the disk and be flush with the surface of the shaft.
« Last Edit: October 05, 2018, 04:20:19 PM by J.L. »

Offline J.L.

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A Shortcut
« Reply #683 on: October 05, 2018, 04:19:21 PM »
Now for the linkage.

I've had success where shear strength is not an issue, to simply glue a boss to a lever rather than try to fabriate the  piece all at once. I could just drill a grub screw hole into the lever, but a boss makes the part look more natural.

The trick is to get the scrap piece of shaft out of the parts before the Loctite sets up!

A bit of hand drawing of the dried part across a piece of emery paper will blend the parts together.

Edit:
I was wrong about the shear strength of Loctite 680. After 24 hours, it is 4000 psi.
« Last Edit: October 05, 2018, 05:39:17 PM by J.L. »

Offline Roger B

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Re: Textile Mill Diorama
« Reply #684 on: October 05, 2018, 07:23:58 PM »
Splendid attention to detail as ever :praise2: The engine looks a smooth runner and I'm glad you sorted the governor linkage  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Offline J.L.

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Re: Textile Mill Diorama
« Reply #685 on: October 07, 2018, 02:33:46 PM »
Thank you Roger.
Yes, I found the governor settings confusing. I think the only way to set the throttle will be to watch the running of the machine, put a finger on the flywheel to represent a load and observe whether the engine is compensating.

As I said earlier, much of this is academic. The model will not be under load much at all. Just the line shafts and the saw and lathe being brought online occasionally for display.

At this point, the engine can be considered finished.



Offline Kim

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Re: Textile Mill Diorama
« Reply #686 on: October 07, 2018, 03:10:25 PM »
You're governor is mighty nice looking John!
Kim

Offline Brian Rupnow

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Re: Textile Mill Diorama
« Reply #687 on: October 07, 2018, 04:54:04 PM »
Lovely engine John. A real masterpiece!!--Brian

Offline J.L.

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Re: Textile Mill Diorama
« Reply #688 on: October 07, 2018, 06:40:17 PM »
Thanks Kim.

Hello Brian. Happy Thanksgiving weekend from Peterborough to Barrie.

This powerful little engine is shaking the table. That's beause there are 5" wheels mounted on the legs so that the model can be viewed from both sides as it is turned around.

To stabilize the table, there will have to be extenders added to the legs to take the weight off of the wheels. I did this also for the 19th century steam driven machine shop diorama. It didn't shake as much though. Victoria has only a 1" bore.

Cheers...John

Offline wagnmkr

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Re: Textile Mill Diorama
« Reply #689 on: October 07, 2018, 07:33:59 PM »
What a Gorgeous engine John. Well Done That Lad!!

Happy Thanksgiving to Peterborough and Barrie from Lindsay.

Cheers
I was cut out to be rich ... but ... I was sewn up all wrong!

 

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