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Thank you.
________________________________________
From: Confocal Microscopy List [[log in to unmask]] On Behalf Of Carl Boswell [[log in to unmask]]
Sent: Thursday, October 28, 2010 1:42 PM
To: [log in to unmask]
Subject: Re: perfusion system
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An appropriate siphon system can provide constant flow for essentially
unlimited volumes. This is a trick used by old (me) column
chromotographists, in which a large reservior is connected to the column (or
small feeding reservior) via a tube that loops lower than the bottom of the
column (or the perfusion chamber). The pressure is determined only by the
height of the small reservoir. Flow from the small reservior into the
chamber causes lower pressure to pull solution from the large reservior. If
I remember correctly, as long as the connecting tube between the reservoirs
loops below the outlet (waste tube from the chamber) then flow (pressure) is
constant. One can continue to replenish the large reservoir because there
is no disturbance of the small one. An added bonus is it can never run dry
because when the large reservoir empties the flow stops when the liquid
level in the connecting tube reaches the same level as the outlet tube.
If you're interested, I could do a diagram.
c
Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX 520-621-3709
----- Original Message -----
From: "Craig Brideau" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 28, 2010 9:03 AM
Subject: Re: perfusion system
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A few years ago one of our students needed non-pulsing flow for a perfusion
setup. As an added catch, the perfusion had to run for over 20 hours, so
syringe pumps didn't have sufficient volume. I managed to find a very tiny
gear pump that provided steadier flow and had enough head to feed from a
fairly deep reservoir jug. Gear pumps basically trap small amounts of fluid
between the teeth of a pair of gears. The flow from the pump is still
slightly pulsing but much better than a peristaltic pump. The pump has been
used for a number of different projects over the years and is still working
well.
Craig
On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler
<[log in to unmask]>wrote:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> The cyclical pressure changes produced by roller pumps will cause movement
> of the chamber and a change in focus.
> This can be eliminated by (a) using a air filled side arm which damps the
> pulsations, as a been mentioned previously, and (b) by making the outlet
> port of the perfusion chamber much wider than the inlet port - something
> rarely seen in commercial perfusions.
>
> Gravity provides pulseless driving force for perfusions and is quite
> cheap.
>
> Jeremy Adler
> Genetics & Pathology
> Rudbeckslaboratoriet
> Daghammersköljdsväg 20
> 751 85 Uppsala
> Sweden
>
> 0046 (0)18 471 4607
>
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