VacSeal question

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
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VacSeal question

Post by Bob_Palmer » Fri Nov 18, 2005 10:25 am

I have an application where I am expereincing a vacuum leak on a viton seal between a loadlock and a gate valve manifold. My loadlock achieves -6 milibar but should get in to the low 7's. When squirting the crease between the loadlock and manifold the pressure rises from 1e-6 to 3 e-6. The gatevalve and airlock manifods are rectangular and the viton oring sits in a rectangular groove on the gate valve manifold. My problem is tthat he dissasembly and repair of this leak is extremely labor intensive and rife with peril. Is VacSeal a viable solution. It seems to me that the VacSeal would have trouble migrating from the crease between the manifolds to the groove where the oring sits. I am also concerned about outgassing, this loadlock has internal baking and can achieve 150degrees C so I guess curing can be done more quickly. Any thoughts are appreciated. Thanks in advance. I sent a word doc attachment showing a picture of the gate valve.
gate valve.doc
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Re: VacSeal question

Post by bevan » Sat Dec 01, 2007 1:26 am

That is a good quality valve you have there.

Have you thought about using a PFPE grease - low vapour pressure, works up to 200° C and has a vapor pressure of 5 x 10-13 @ 20° C. Not cheap - but I know a few people who swear by it.

Try some Fomblin Y-Vac3 - you can get it at Leskers for $80 per tube, should last you a while.

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