Hello Kenneth,
I do not know if this would be applicable. But when I was at York College
of PA, the compressor we were using would only barely produce the 80psi
(5.5 bar) and I noticed that suddenly one time we kept having an issue with
the sample getting to above the magnet but not releasing. It turned out
that the pressure was enough to get it to the top and start moving but not
enough to get it to the end and let the sample go. It turned out that the
issues corresponded with a large number of people needing the house air at
the same time, and that drop of a few psi was enough to cause the problem.
I don't know if you have a dedicated air supply or a house one but thought
I would add my two cents. (am still pretty new here)
Sincerely,
Silas
On Wed, Mar 6, 2024 at 12:30 PM DrSpin <rajanp_at_uw.edu> wrote:
> Hi Ken
> I see that you guys are talking about this in the specific context of
> sample changers and so this is a bit of a tangent. On one of my manually
> operated instruments, the spinner was getting stuck on top of the BST. The
> cause turned out to be rather mundane i.e. oily deposits that seemed to
> have accumulated (over a period of thousands of human hours) just about an
> inch below the top so it is not easily visible. The seemingly mild deposit
> was enough to cause a block preventing the spinner descending smoothly.
> Cleaning it with Kimwipes and IPA took care of it. Even in 2024, looks
> like the laws of Physics operate the same way and the good old lessons of
> ensuring that the sample tube and spinner are clean before you put them in
> the magnet, seems to hold good !
> Gave me an opportunity to boast about the fine engineering tolerances
> that are involved in making an NMR machine tick, to some green horn users.
>
> Best
> Rajan
>
> On Wed, Mar 6, 2024 at 7:03 AM ter Horst, Marc A.
> wrote:
>
>> Hi Ken and Hasan
>>
>> Yes. On two of our systems with a SampleXpress. Went through the
>> same adjustments, o-rings, spinners, source compressed gas pressure, sample
>> lift adjustment. Also tried re-adjusting the bed of the SampleXpress and
>> with a level. Does this happen with ‘regular’ 5mm tubes
>> or J-young tubes
>> or both?
>>
>> Will try Hasan’s recommendation (Thank you!).
>>
>> Marc
>>
>>
>> *From:* main_at_ammrl.groups.io On Behalf Of *Hasan Celik via groups.io
>> *Sent:* Wednesday, March 6, 2024 10:00 AM
>> *To:* main_at_ammrl.groups.io
>> *Subject:* Re: [AMMRL] Bruker SampleCase: Samples getting stuck as they
>> are dropped down the transport tube
>>
>>
>> Hello Ken,
>>
>> We had this problem before. It turned out that the bolts holding the
>> metal part that guides the spinner into the transport tube got loose over
>> time (~5 years after the installation). I had to remove the plastic
>> transparent plastic cover around the unit to access them. Once I lined up
>> the metal part that latches onto the plastic tube and tightened the bolts,
>> it didn't happen again.
>>
>> Best,
>>
>> Hasan
>>
>>
>>
>> On Wed, Mar 6, 2024 at 6:54 AM Kenneth Sharp-Knott wrote:
>>
>> Has anyone had any issues with their spinners getting stuck at the top of
>> the transport tube as they are dropped? It is a little difficult to see
>> just why they're getting stuck, but they appear to be kinked at an angle at
>> the top of the transport tube.
>>
>> I've changed the rubber band - no effect.
>>
>> The air pressure may be a bit lower than what Bruker wants 5.5 bar vs 6,
>> but it's the same exact air pressure I've had since it was installed.
>>
>> Seeking the usual wise advice and counsel for the AMMRL greats.
>>
>> Ken Sharp-Knott
>>
>> Manager of Analytical Services and the NMR Facility
>> Department of Chemistry
>> Virginia Tech
>>
>> (540)267-6502 (Cell)
>> (540)231-0885 (Office)
>> --
-
*Silas Brown **(He/Him)**, Instrumentation Specialist *
Department of Chemistry
Williams College
150B Morley Science Laboratories
Williamstown, Ma. 01267
E: seb14_at_Williams.edu | P: 413.597.3544
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Received on Wed Mar 06 2024 - 09:41:47 MST