For the newbies--flow meter here means sticking the end of the
capillary into a vial of water and looking for bubbles to form ;)
At 0.5 mL/min, it takes a little while.
Also, capillary connections to the valve can be tricky. If the
capillary is stuck in too far, it can break and scratch the
rotor. If it's not in far enough, you won't get a good seal--that
is every time you tighten the connection you can also push the
capillary out a little. You can even end up crushing the end of
the ferrule and clog it.
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If you connect a flowmeter to the vents of your valco valve, do you see a flow? If yes, does it change when you go from load to inject modes? Is your actuator aligned with your valve?
CédricOn 9/27/2018 12:20 PM, Scott Wieman wrote:
[log in to unmask]">Hey all,
We're currently trying to get our GasBench up and running after a long period of inactivity. We've plumbed the 0.3% CO2 in He line directly into the GC column (and saw CO2!) and into the bulkhead that normally holds the sampling needle capillary (and we don't see any CO2). The issue seems to be with the valco 8-way valve and leaks initiating with it. We now have the water trap plumbed into port 5 on the 8-way valve so it feeds directly into the GC in load mode, but again see nothing. Our helium leak detector is showing major leaks at both screws, but the ferrules are biting the capillary well in both cases and we've remade the connections a few times to no avail. We're currently using FS1.5 ferrules for fused silica running in and out of the 8-way valve and ZRF1.5 ferrules for the silcosteel. Have other folks had this issue before? Are there other ferrules we should be using for the 8-way valve? Thoughts or suggestions are highly appreciated!
NASA GSFC | UMBC | CRESST II--
Scott Wieman, M.A.Planetary Environments Laboratory, Code 699