Re: Trapping radioactive material from rotary-vane pump exhaust

Steve (Steve@atrbiotech.com)
Tue, 5 Jan 1999 11:51:34 -0500

The problem with trapping after the pump stems from two sources. The first
is that the discharge vapor carries a fair amount of heat with it from the
pumps mechanical frictional losses. The added heat has to be factored into
the sizing of the cooling system in the trap to insure a high percentage of
containment. The other concern is the solvents used in this application have
melting points that may be lower than single stage refrigerated traps ( -50
C with todays refrigerants) . LN2 offers temperatures that are low enough
for efficient trapping but the process of maintaining fluid levels in the
dewar flask require constant attention. How about a large bed charcoal trap
post pump, there are several sizes available.
-----Original Message-----
From: swilbert@Imail.neorx.com <swilbert@Imail.neorx.com>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Date: Tuesday, January 05, 1999 1:46 AM
Subject: Trapping radioactive material from rotary-vane pump exhaust

> Hi all,
>
> we are planning on analyzing samples containing trace amounts of
> tritium-labelled compounds using our LC-LCQ system. I am looking for
> advice on efficiently trapping possibly radioactive exhaust fumes
> generated when ballasting the rotary-vane pump. Any help is greatly
> appreciated.
>
> Thanks!
>
> Sibylle Wilbert
> NeoRx Corp.
> 410 West Harrison Street
> Seattle, WA 98119-4007
> Phone: (206) 281-4001 ext.250
>
>
>______________________________ Reply Separator
_________________________________
>Subject: Buffer make-up programs.
>Author: "Scharin, Eric" <eric.scharin@Covance.com> at IMail
>Date: 1/4/99 5:38 PM
>
>
>I used to use a shareware program (of unknown origin) called "Buffer" to
>aid in buffer make-up. You could pick an acid, input the desired pH (it
>would tell you if you were out of range), ionic strength, molarity, and
>temperature and it would output the quantities (per liter) of acid,
>conjugate base, and salt for the recipe. It really sped up the design
>of formulation experiments (especially constant ionic strength designs).
>
>Unfortunately, the program was written for the Mac, and only ran on
>older Mac OSs. My question to the list: does anyone know of a Windows
>program (shareware or otherwise) that will serve the same functional
>requirements?
>
>Thanks.
>
>Eric Scharin
>Technical Services
>Covance Biotechnology Services
>
>
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