Question: Troubleshooting the Bucket Monitor

sarasage is asking a question about bucket-monitor
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by sarasage | September 14, 2021 00:45 | #27724

Checking with the Public Lab community to see if anyone can assist me with some issues I am having with the bucket monitor.

I had a perfect opportunity to pull a grab sample last week, but could not get the Tedlar bag to inflate. I suspect the failure was because I had left the intake port plug off of the monitor, but there are other questions I have, as well:

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The intake port plug was replaced. I think its absence prevented the Tedlar bag from inflating.

Does the black valve on the Tedlar bag need to be closed completely?image description

Also, what is the valve for and what happens if you loosen it?

Does every Tedlar sample require single-use ferrules and a nut?

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Is it correct to assume you need a front and back back ferrule, as well as a Swagelok end nut per grab sample?

Should the pump be set to inflate, not deflate?image descriptionimage description_

Seems like an obvious question, but I want to verify. Thank you!


The ferrules and the nut usually feed the gas sampling port of the GC/MS. Although there are many other instruments that can use them. Can't help with anything else. We only ran the gas samples a very few times. Usually, we did heart cutting of a sample from the HPLC to the GCMS. We avoided the cost of an LCMS this way when the instruments were much more expensive and unreliable.

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@kgradow1 wondering if you have any troubleshooting ideas?

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1) The bag will not inflate if the valve is completely closed 2) The nut is reusable, and the ferrule is too if you're careful (you can tighten it slightly, enough to hold it in place, but not so tightly that you can't slide the Tedlar bag in and out). You sort of need to have a light touch to do this -- if you accidentally overtighten it it's not a problem, you just have to cut the ferrule off before you send it in. If it's overtightened, you can still use the bag, but you can't reuse the ferrule. 3) It should be set to deflate, since you're trying to suck air out of the container (in order to get the bag to inflate). That said, f you're not sure which way the pump is working and want to do a trial run, you can also rubber band a regular old plastic bag to the utake port - make sure there's a clear path for air to get in - and run the pump to see if you have it set up right. That way you can test proof of concept without having to use an entire Tedlar bag.

Hope that helps!

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