Nick:
One other comment regarding the old Mod. Ltd. furnaces.
After developing a water jacket leak in our original furnace can, we
had a new furnace can built with a couple of useful modifications:
1) A vertical mounting flange welded near the middle of the
can. This mounting flange makes makes it easy to mount the furnace,
and provides complete support even with top and bottom flanges
removed.
2) Oversize top and bottom flanges containing water cooling
passages. These passages are machined slots near the outer
perimeter of each flange with covers and water fittings welded on.
These new cooling flanges have eliminated our troublesome copper
cooling collars, and provide more efficient water cooling, which
seems to have measurably reduced the furnace blank a little bit.
Bill McIntosh
>>Hi Nick,
>
>
>We have the moly made up at Schwarzkopf and the welding done at
>Applied Fusion. Total cost is about $500 each. We use a 3/4" o.d so
>the heat shields on the Mod. Ltd. furnace need to be opened up a
>bit,otherwise the length is still 8 3/4". We use the larger o.d. so
>that the liner is more easy to remove. We neck-down the i.d. at the
>bottom 1" of the crucible so that a ca. 0.550" liner fits tight but
>doesn't get stuck higher up in the crucible where all the "crude"
>precipitates. Depending upon what we are doing we can get several
>liner changes. The crucible itself seldom if ever fails, but
>eventually a liner will crack and melt will stick it to the crucible.
>
>Matt
>
>
>>Hi Matt
>>
>>Thanks for the info. Where do you have to Mo crucibles from and what
>>size are they ? Do they fit in the old Mod. Ltd furnaces ?
>>
>>Cheers
>>
>>Nick
>>
>>
>>At 08:33 12/10/01 -0600, you wrote:
>>>The NMGRL long ago stopped using ion pumps on the extraction line due
>>>to high background problems. The MAP-215 still has the Tri-ode ion
>>>pump provided by MAP and has not had any background problems. At
>>>UCLA (when I was there) the VG3600 had a Starcell and there was never
>>>a background problem, however on the extraction lines the Starcells
>>>were a problem. We here at New Mexico are very happy with our Varian
>>>V-70 turbo pumps for all parts of our extraction line.
>>>
>>>Modifications Limited is marketing Nb crucibles in place of the too
>>>expensive Ta crucibles. We tested a Nb crucible for a day and found
>>>it acceptable, however never put it through a good workout. We will
>>>continue to use the Mo crucibles which have served us so well during
>>>the past several years. They have low blank, are very durable, and
>>>cost effective.
>>>
>>>Matt
>>>
>>>--
>>>Matt Heizler
>>>NM Bureau of Mines and Mineral Resources
>>>NM Tech
>>>801 Leroy Place
>>>Socorro, NM 87801
>>>
>>>Office 505-835-5244
>>>Argon Lab 505-835-5271
>>>Main Office 505-835-5420
>>>FAX 505-835-6333
>>>http://geoinfo.nmt.edu/staff/mheizler/home.html
>>
>>___________________________________________________________________________
>>Dr Nicolas ARNAUD, PhD UMR 6524 CNRS
>>Chargé de recherche CNRS Lab. "Magmas et Volcans"
>>Tel: (33 0) 473 34 67 11 5 rue Kessler
>>Fax: (33 0) 473 34 67 44 63000 Clermont-Ferrand France
>>[log in to unmask]
>>http://wwwobs.univ-bpclermont.fr/lmv/index.html
>>
>>Section 11 Serveur intersyndical WEB:
>>http://wwwobs.univ-bpclermont.fr/partners/CN11/index.html
>>____________________________________________________________________________
>
>--
>Matt Heizler
>NM Bureau of Mines and Mineral Resources
>NM Tech
>801 Leroy Place
>Socorro, NM 87801
>
>Office 505-835-5244
>Argon Lab 505-835-5271
>Main Office 505-835-5420
>FAX 505-835-6333
>http://geoinfo.nmt.edu/staff/mheizler/home.html
--
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William C. McIntosh
[log in to unmask]
Volcanologist/Geochronologist
New Mexico Geochronology Research Laboratory
N.M. Bureau of Geology
New Mexico Tech
801 Leroy Place
Socorro, New Mexico, 87801-4796, USA
505-835-5324 office; -5271 lab; -6333 Fax
----------------------------------------------
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