I haven't worried about the dewar; the spinner has a hole through it (that's the whole problem) so there is plenty of flow and not that much pressure buildup. The real weak link is the rubber hose that connects to the dewar on the bottom of the probe, so any significant pressure buildup will simply pop that hose off. I have only seen one of those pop off once. Worrying about the glass inserts may be a more valid point. Perhaps a more seasoned lab manager can tell me how risky my approach is. I picked up this trick from the NMR facility at the University of Utah where they have been using it for decades without problem. Personally, I am more concerned about damaging things by sticking long sticks and other objects into the bore so I was surprised how common recommendations along those lines were. Anyhow, to each his own.
-Scott
On Nov 15, 2011, at 2:03 PM, Stolowich,Neal J. wrote:
> In my experience, cranking the sample lift air up usually does not work with the heavier Varian spinners and most probes, but I haven't tried cranking up the VT air as well. But one question- don't you worry about possible effects to the VT dewar and probe glass inserts by that amount of air flow going through the probe, instead of from above the probe?
>
> Cheers!
>
> Neal J Stolowich, Ph.D.
> NMR Facilities Manager
> Department of Chemistry
> University of Louisville
> Louisville, Kentucky 40292
> Office: (502) 852-7894 Fax: (502) 852-8149
>
>
>
>
> -----Original Message-----
> From: Scott Burt [mailto:scott.r.burt_at_gmail.com] On Behalf Of Scott Burt
> Sent: Tuesday, November 15, 2011 12:00 AM
> To: AMMRL
> Subject: Re: AMMRL: How to retrieve empty spinners
>
> I'm surprised no one has mentioned the easiest method of getting the empty spinner out of the upper barrel: simply crank the VT air up to 30 or 40 and the spinner floats up just fine without any of the complicated methods suggested earlier.
>
> We have enough undergraduate researchers and undergraduate labs using our 300 MHz Inova that I end up doing this once or twice a month. I've had to do this at least once or twice on our 500 MHz Inova as well. This should not be a complicated or time consuming endeavor; just use the VT air and your back in business in less than 30 seconds.
>
> -Scott
>
> ---
> Scott Burt
> Assistant Teaching Professor
> NMR Facility Manager
> Department of Chemistry and Biochemistry Brigham Young University C008A BNSN Provo, Utah 84602-5700
> Phone: (801) 422-2404
> Fax: (801) 422-0153
> email: scott_burt_at_byu.edu
>
>
>
>
>
> On Nov 14, 2011, at 12:58 PM, Rudi Nunlist wrote:
>
> > Another way is to use a round wooden dowel. Those were used quite frequently.
> > The UCB wood shop has some that fit an empty spinner bore pretty well.
> > Hardware or hobby stores might have them as well.
> >
> > For the reverse situation, where users forget the spinner and drop the
> > sample into the magnet, the same dowels and a loop of double sided
> > tape works for fishing the sample out.
> >
> > Both methods had to be used more than once, they are well tested.
> >
> >
> > Best Regards,
> >
> > Rudi Nunlist
> >
> >
> > ------ On Sun November 13 2011 11:43, gozim_at_nmr.uni-frankfurt.de wrote:
> > =Spinlanders,
> > =
> > =before you start to dismount your probe holder to fetch an empty
> > =spinner (without a tube) try the following:
> > =Insert the next sample as usual, and lift it again.
> > =
> > =Have a good field,
> > =
> > =JGZim
> > =
> > =
> > =
> > =
> >
>
>
>
Received on Tue Nov 15 2011 - 17:30:21 MST