All,
This is something my instrument engineer Steve Wiemholt found that has changed our lives in the lab: since we've installed these "soft start" check valves in the roughing pump lines a few years ago, we haven't had a single blown detector or column separation window on either our SX50 or our SX100 instruments!
Even when we've done a few no-nos such as pumping the chamber without holding up the stage chamber body after it had been dropped. Usually a guaranteed blown set of windows when that happens! But we've had not a single window needing replacement...
Here's the link:
http://www.lesker.com/newweb/valves/pdf/kjlced09_sec02_pages34-35_butterflyvalves.pdf
It's the "soft start" KF valve at the bottom of the page.
My engineer says: The Kurt J. Lesker part number for their KF40 sized soft start check valve is M2250040. The KF40 is the smallest size. This will necessitate use of KF25 to KF40 adapter fittings.
This might even be useful for JEOL probes but not sure about their detector window robustness under normal circumstances.
Manufacturer page:
http://www.vatvalve.com/products/catalog/H/311_1_A
This is interesting. A short relative question: what are/was pipe length from roughing pump to EPMA in your case before upgrading with these valves and experiencing window blowout? I think in our case long lines (~9m) soften pumping too, however as we plan to move our probes to different location, I think the technical room will be closer and pipes could be practically shortened, or even upgraded to steel less leaky pipes, and I consider then such Valves would be nice to have to protect the windows. As far I am thinking about this it should be installed only on pump for general pumping. For sure it should be not installed on Diffusion pump roughing pump. Also Probably It could be installed closer to EPMA, probably best placement would be to insert it in between roughing pump pipe and vacuum distribution box of EPMA. It does not need to be placed close to pump?
Quote from: sem-geologist on January 27, 2026, 08:05:24 AMThis is interesting... could be installed closer to EPMA, probably best placement would be to insert it in between roughing pump pipe and vacuum distribution box of EPMA. It does not need to be placed close to pump?
Good question.
We installed it right at the roughing pump because the clamps were designed to fit on the pump adapter. I guess it could be installed anywhere but the further from the detector windows seems better to me.
Our roughing/backing lines were pretty short, maybe only a couple meters.