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Old 11-13-2017, 04:52 PM   #1
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Default Stuart triple expansion

My triple expansion project almost completed. It won't run on compressed air. Is this because compressed air doesn't expand and steam does? Hope some one has an answer for me. That or my valve timing is not correct. Thanks Larry. I should have read other posts on this issue first. Will not run on compressed air. That's what I was afraid of. Now I have to build a boiler. Thanks everyone.

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Old 11-13-2017, 06:53 PM   #2
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I've built a double expansion and it runs on compressed air. True that compressed air doesn't expand as steam does, but I think there is something else wrong as it should run on just the primary cylinder.
Depending on pressure there will be some pressure passed to the secondary cylinder. It may not run perfectly but I think it should run. Can you isolate the primary and see if it runs?

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Old 11-13-2017, 09:54 PM   #3
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It should definitely run on compressed air.
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Old 11-13-2017, 11:18 PM   #4
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Fault timing of the triple expansion steam engine..

You must connect the air pressure to the cylinder and adjust the timing and test running in H.P, then I.P cylinder and last L.P cylinder.

To running test for each cylinder: Remove the two connecting rod to other cylinder who is not in use (due less load caused by friction), the cylinder who is under test/adjusting timing must have connecting rod to run the steam engine. Also you are adjusting/running the triple steam engine as if it were "one cylinder steam engine".

After each cylinder has correct timing and running test for each cylinder is done, mount all connecting rod and the two manifolds on place and the triple steam engine is ready to run.

Here is my triple expansion steam engine running on air pressure under test.

Jens Eirik, Bergen in Norway :)
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Old 11-14-2017, 03:50 AM   #5
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Thanks for the info. I'll work on this based on your 1 cylinder at a time approach. Nice engine Mechanicboy. Great video.

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