Diaphram life?

Discussion on Stirling or "hot air" engines (all types)
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Crazyguy
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Joined: Sun Jun 07, 2015 10:39 am
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Diaphram life?

Post by Crazyguy » Tue Mar 29, 2016 4:43 pm

I've seen lots of engines running with diaphrams. Has anyone ever had one last a long time before tearing?
Is this a reliable design for a real engine and not a toy?

Ian S C
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Location: New Zealand

Re: Diaphram life?

Post by Ian S C » Wed Mar 30, 2016 1:40 am

A diaphragm should last quite well, couldn't say how many hours, but think of the diaphragm in the fuel pump on a motor car, or in a gas regulator. These last for years.
Ian S C

Crazyguy
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Joined: Sun Jun 07, 2015 10:39 am
Location: USA

Re: Diaphram life?

Post by Crazyguy » Wed Mar 30, 2016 8:31 am

I was thinking if you had a diaphram fail on a stirling that pumped it's own cooling water, the engine would stop when the diaphram failed, which would stop the cooling water flow, but the heat source (fire) would be unstopped and the engine and components would overheat (burn up) . It would have to be attended or monitored, or have a thermostat to stop the fire. Or maybe a bimetal vent that would let the heat escape if it got too hot.

Ian S C
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Location: New Zealand

Re: Diaphram life?

Post by Ian S C » Thu Mar 31, 2016 1:06 am

I think the nearest to a diaphragm in commercial Stirling engines is the "roll sock" seal on a piston, these are rated for tens of thousands of hours continuous running.
In case of break down some means of auto shut off for the gas could be arranged.
Ian S C

Crazyguy
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Location: USA

Re: Diaphram life?

Post by Crazyguy » Thu Mar 31, 2016 5:27 am

I think the "roll sock" type of diaphram is good.

Wellington
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Re: Diaphram life?

Post by Wellington » Fri Apr 29, 2016 3:53 am

Ian S C wrote:I think the nearest to a diaphragm in commercial Stirling engines is the "roll sock" seal on a piston, these are rated for tens of thousands of hours continuous running.
In case of break down some means of auto shut off for the gas could be arranged.
Ian S C
Tens of thousands of hrs running time is good enough for me. But what about materials? Which easily available materials will give the longest life do you think?
.Wellington.

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