Does anyone know this type of seal?

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
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Jeroen Vriesman
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Does anyone know this type of seal?

Post by Jeroen Vriesman » Tue Nov 15, 2016 3:16 pm

Have a new vacuum chamber, but two of the seals have an unknown type.

And I think I need to replace them.
It's all full-metal, and the seal seems to be a long fine circular spring with aluminium. It looks like a re-usable type of wire seal, but I don't know if it's re-usable.
The chamber is Leybold Heraus.

The thickness of the "wire" is about 4mm, and the inside diameter is 453mm.

One side of the flange is completely flat, the other side has a 3mm deep groove for the seal.
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Jim Stead
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Re: Does anyone know this type of seal?

Post by Jim Stead » Tue Nov 15, 2016 4:14 pm

I believe that's called a C Ring seal. They come spring energized (like yours) and without the spring.

Andrew Seltzman
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Re: Does anyone know this type of seal?

Post by Andrew Seltzman » Tue Nov 15, 2016 5:29 pm

helicoflex
Andrew Seltzman
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Joseph Venne
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Re: Does anyone know this type of seal?

Post by Joseph Venne » Tue Feb 21, 2017 11:54 am

I too think that it's a helicoflex.

Jeroen Vriesman
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Re: Does anyone know this type of seal?

Post by Jeroen Vriesman » Tue Feb 21, 2017 12:09 pm

Yes that was the correct answer, question is a few weeks old.

Chamber is operational now, but there are still some leaks.

Since helium leak detectors are very expensive, I will try with 5%H2-95%N2 and a hydrogen sensor to find the leak.

I ordered a TGS821 sensor, which can detect 50ppm H2, but I'm a bit in doubt about how to proceed with it. It's made for atmospheric pressure air, so it seems to be logical to place the sensor at the exhaust of the fore vacuum pump.
But, the oil from the pump might contaminate the sensor, maybe... I do have a mist filter.

I can also place it between the turbo and the fore vacuum pump, but would it work at E-1 mbar? The sensor is an alumina substrate with sintered SnO2 (semiconducting), the resistance of the SnO2 drops in the presence of H2, but the absolute H2 pressure is much lower at E-1 mbar. Would it work? we will see.

Johan Reinink
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Re: Does anyone know this type of seal?

Post by Johan Reinink » Wed Feb 22, 2017 5:37 pm

50ppm is a partial pressure in the order of 5 E-2 mbar if I'm correct, very low for leak detection. How big is your leak?

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