2/14/97
the same room as our vacuum evaporator. Although we have an oil mist filter
on the VE, we get some smell from the rotary pump when roughing out the
bell jar. Any suggestions on how to eliminate this problem, the computer
users have objected to the smell and possible health concerns.
Are some filters better than others? How realistic is it to expect a filter
to eliminate all odor? I have considered venting the pumps to another room
and putting a big industrial filter there, but am worried about oil
condensing out in the vent pipe on its way to the filter. The campus
facilities folks are reluctant to vent the pumps into the building exhaust
because it will involve rebalancing the whole building etc. But they might
be up for putting in a vent to another room if we can figure out how to do
it without creating other problems.
Any ideas?
Jonathan Krupp
Microscopy and Imaging Lab
University of California
Santa Cruz, CA 95064
(408) 459-2477
FAX (408) 429-0146
jmkrupp@cats.ucsc.edu
There are several ways of dealing with rotary pump vapours. One pump
salesman told me that the best filter was a giant, movie-house bag of
popcorn! Great oil absorber and cheap to replace. I have vented most of my
pumps out the window or into the fume cupboard. I'm very surprised that the
building people were concerned about the building exhaust, since the vent
pipe is so small (one inch or less) and there is almost no movement of air
through the vent pipe, and that only for a few seconds until a bit of
vacuum is established.
If you lead a long pipe into another room, there is no harm in the vapours
condensing in the pipe, that eliminates some of the problem. The computer
users are correct, oil vapours are a health hazard if inhaled.
Mary Mager
Electron Microscopist
Metals and Materials Eng., UBC
6350 Stores Rd.
Vancouver, B.C. V6T 1Z4
CANADA
tel:604-822-5648, fax:604-822-3619
e-mail: mager@unixg.ubc.ca
When new, I feel that some oil mist filters are quite effective, but over
time I'm sure their efficiency drops significantly. Personally, in any
installation where a rotary pump is frequently moving large volumes, such
as evaporators and SEMs, I would recommend venting the rotary pump to
outside the building.
Regards,
Larry Stoter
LPS@teknesis.demon.co.uk
If at all possible try to vent your RP into a fume hood or outside.
You can also double filter the exhaust by making a 3-4" dia
PVC sealed tube about 10-12" long with screw cap plugs on each end.
I've done this in the past with good results.
You have to drill a hole in the top and botton and thread in a pipe nipple
the same size as the pump outlet at the bottom of the cylinder.
Adapt this to fit the threads ofa Balston disposable vapor filter which
will sit on the inside of the cylinder. Drill another hole in the top
cap and tap it to fit another Balston filter.
I can fax you a drawing if you are interested. Just emailme your FAX #.
cheers
Ed Basgall, PhD
Penn State Univ
Dept of Chem
University Park, PA 16801
edb@chem.psu.edu
of our roughing pumps up an "elephant trunk", which is just a
small hose (about 5" diameter) that goes up into the house
exhaust, the same as our chemical hoods are vented into. We don't
know the effect of the slight oil vapors on our health, but
there's no reason for us to take a chance. I hope you can enjoy a
healthy work space too.
If this solution is impossible, please use some sort of absorbant
material and check it periodically to see when it is approaching
saturation. The best part of our solution is that it needs no
attention on our part.
deking@vnet.ibm.com
I use Balston, Inc. filter Type 9955-12, Grade 371H on my vacuum evaporator
mechanical pump, two Sargent-Welch mechanical pumps, and a Marvac Z-30 direct
drive pump I use for pumping my vacuum desiccator for TEM film. They have a
threaded mount that fits many mechanical pump oil mist eliminator ports
directly. In the case of the Sargent-Welch, I ordered an adaptor from big
supplier of those pumps. like Fisher, etc., or adapt your own.
The metal oil mist "eliminators" that come with many mechanical pumps are often
totally useless. This Balston filter eliminates 99% of oil vapor mist, plus they
have a small tube that sticks out the bottom side for oil to drain out of. I put
a short length of plastic lab tubing from it to a small 50cc bottle to collect
filtered oil and eventually just put it back into the pump once per year. They
are inexpensive.
Balston is in Lexington, MA. Try these filters. Good luck!
Gib Ahlstrand, MMS Newsletter Editor
Electron Optical Facility, University of Minnesota, Dept. Plant Pathology
495 Borlaug Hall, St. Paul, MN 55108 (612)625-8249
612-625-9728 FAX, giba@puccini.crl.umn.edu
It may be that the filter insert in your existing oil mist filter
has reached saturation. The need to change the insert will depend your
frequency of use. The amount of oil vapor passing through a good quality
clean filter should be minimal and the health problem probably not serious
if entering a room with adequate air turnover. I agree that if you can smell
the oil it's undesirable.
Depending on how much you run the evaporator, I would be as concerned
about my mental state. The noise from those things can be nerve-racking!
Don Gantz
Boston Univ Med School
gantz@med-biophd.bu.edu
Regarding rotary pump oil vapors in areas where one
cannot vent the pumps outside. I had posted a reply
to J. Krupp about a double filter set-up I had
constructed while serving time at U of Ill. This
design has worked well for such an application.
Several others had inquired as to the construction of such a unit.
I have a drawing available for the do-it-yourselfer
or would be willing to construct one (or several) and send it out
for a modest price to anyone interested. Please contact me via
email: edb@chem.psu.edu if you would like further information on
such a unit. If there is enough interest I may just quit my day
job and produce these full time.
cheers
Ed Basgall, PhD
Penn State Univ
Dept of Chem
State College, PA 16802
Ph: 814-865-0493
FAX 814-863-0618
edb@chem.psu.edu