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Question about diaphragm material

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Jens Eirik Skogstad07/04/2017 17:31:08
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Hi folks!

I created the gas stop valve and gas attenuator.

But the problem is teflon/PTFE sheet is noe easy to buy in Norway.

Can i use the thin silicone sheet as diaphragm cut from the silicone form for baking who is sold by kitchen shop?

The silicone seem soft and strong material and can withstand up to 250 degree Celsius/482 degree Fahrenheit.

Or must it be teflon/PTFE sheet as diaphragm?

 

Edited By Jens Eirik Skogstad on 07/04/2017 17:33:48

JohnF17/04/2017 00:34:20
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Cant answer your question Jens but this will bump it to the top again !

Brian Baker 117/04/2017 08:31:10
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Greetings Jens,

I think that PTFE sheet can be purchased on Ebay, and I trust you can access that site.

Regards

Brian

John Haine17/04/2017 08:54:37
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I'd have thought that silicone would be better than ptfe, the latter is not very strong but silicone is very hard wearing.

Neil Wyatt17/04/2017 09:40:04
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Not sure of your application, but LPG regulators in cars use thin rubber sheet.

They potentially run at 100 degrees (heated by engine coolant) although the LPG evaporating takes the edge off that.

Neil

Ian P17/04/2017 10:11:23
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I would have thought that the selection of diaphragm material and thickness would be dictated by the pressures involved and the mechanical design (diaphragm diameter and deflection distance)

You have not given any indication of the purpose (is this a gas flow regulator?) so I'm only speculating. If you need PTFE or silicone for their chemical resistance then it possible that you could use a metal diaphragm for its mechanical strength but have a thin plastic membrane clamped on the face that is in contact with the media.

Ian P

Keith Long17/04/2017 10:26:37
781 forum posts
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Jens - you don't say what thickness of ptfe you need but Direct Plastics list sheet down to 0.25mm. The smallest piece that they show on their website is 300mm square at £1.70 + vat. I would have thought if that material is suitable getting them to post it to Norway should be possible.

I've bought from Direct plastics in the past and found them very easy deal with.

Keith

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