http://www.norhof.com/norhof2002/index.html   pressurized dewars, control software

http://www.barber-nichols.com/cryogenic.htm   expensive looking submersible pumps

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   Paul F. Dennis, Alex Etchells, and David Blomfield

   Review of Scientific Instruments Vol 70(9) pp. 3778-3779. September 1999

Abstract
      We describe the principle of operation and construction of an inexpensive, reliable system for the automated dispensing of liquid nitrogen from a single supply Dewar to multiple cryogenic traps. The system can be run under full computer control and in conjunction with existing designs of traps will allow unattended operation over long duty periods combined with programmed temperature cycles. ©1999 American Institute of Physics.

Indexing separation, materials handling, physical instrumentation control, temperature control, computerised control, flow control, low-temperature techniques, nitrogen, valves
DOI 10.1063/1.1149993 
URL http://content.aip.org/RSINAK/v70/i9/3778_1.html

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Inexpensive liquid nitrogen pump
    D. Chopra and H. Babb

   Review of Scientific Instruments Vol 46(8) pp. 1126-1127. August 1975

Abstract
      We describe the design of a simple and inexpensive system for transferring liquid nitrogen from one container to another.

DOI 10.1063/1.1134371 
URL http://content.aip.org/RSINAK/v46/i8/1126_1.html
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