Vacuum pumps

Robert Horton horton at molbio
Thu Jun 11 13:51:34 EST 1992

Klaus.Matthaei at writes:
: Dear Netters
: Water vacuum pumps can work well unless of course there is a pressure drop
: and you crack your gel.  However, it must be lovely to be able to afford to
: blow away 400 gallons of water (your words) everytime you want to dry down
: a gel or an oligo.  Those of us that live on the dryest continent in the
: world cannot afford to do so and I sugest with our ever increasing
: population neither can the rest of the planet. I remember the severe
: drought of the summer of 1980 in New York when water trestrictions
: prevented us washing cars, watering lawns and even flushing the toilet when
: we wanted.  How would you have dried your gel there?
You have a point; the impact of 400 gallons of water use depends a lot 
on where you are. In New York (or LA for that matter), I'd use my smokey 
old vacuum pump (who'd notice?:( )

: As for the oil and smoke, the new dry pumps contain no oil and were
: designed to overcome exactly that type of problem.  (I am not a company
: rep!!)  
It must be lovely to be able to afford a $1500 gel dryer:)
: Most disturbing I find comments trying to justify polluting our environment
: ourselves just because other things are worse.
It wasn't meant to be a justification of pollution. You cannot exist in this
world without affecting the environment. It is rational to attempt to make
choices that minimize detrimental effects. The environmental effects of many
of our actions are quite complicated and it is NOT always possible to make
environmentally sound decisions just by "common sense". I was trying to
point out that a water aspirator MAY NOT be worse for the environment than
the smelly old vacuum pumps most people use. I'm sure it depends on where
you are, etc., but I don't think the answer is so simple as "water use is
bad"; what is the environmental impact of using 3kg of dry ice? The point
about other things being worse is that it probably isn't worth doing an
environmental impact study to find out the effects of 3kg of dry ice.
And if you are going to spend $1500 to fight pollution, I think there must
be better ways than buying an environmentally friendly vacuum pump. 
   If it makes you feel better, I think the suggestion made by
gbga13 at about making an aspirator-based vacuum pump that
recycles the water is a terrific one; it looks like one could be built for
~$150, and it would not be subject to fluctuations in water pressure. When my
conscience can no longer stand the thought of "wasting" 400 gallons of water
to dry an oligo, I'll probably build one.
Bob Horton            /\ "Crash programs fail because of the theory that
U. of Minnesota, CBS  || with nine women pregnant you get a baby a month" 
1479 Gortner Ave.    /||\                    -Werner von Braun. 
St. Paul, MN 55108    ^^   horton at 624-3790

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