SERVALL

CENTRIFUGES

Kwan Sorwall, Ine.

NORWALK, CONNECTICUT, U.S.A.

 

CABLE ADDRESS: “SWEDEGOODS” December 1, 1959 TELEPHONE: VICTOR 7-2491
PLEASE REPLY TO:
NORWALK, CONNECTICUT

Our Ref: NLC:GS

AIR MAIL

Dr. J. Lederberg, Head

Department of Genetics

Stanford University - School of Medicine
Palo Alto, California

Dear Dr, Lederberg:

We received, a couple of weeks ago, a report from our Mr, Soderlund with whom you
discussed, at that time, your idea of a liquid-filled bowl centrifuge.

We had given preliminary thought ® such a rotor years ago after collaboration with
Dr. Bob Backus, who was then at the University of California, on his method of
suspending micro-tubes (1/2 ml. volume) in standard 50 ml. fluid-filled tubes in
the SS-1 Centrifuge. His results approached those of an ultra-centrifuge, but,
of course, the volumes were terribly small, His end use was analytical rather
than preparative however.

The basic problem encountered is structural, which exhibits itself in size, weight
and expense, Tied in with this comes acceleration rate and deceleration rate,
reasonable limitation of which results in control and drive expense.

It is our understanding from Torsten that you would like to be able to swing tubes
up to 50 ml. capacity, specimen Rs Fup to 1.5 and at speeds in the superspeed
range,-i.e., 10 to 20,000 rpm. These parameters are extremely tough In the design
of our HS Rotor, We encountered them to a great extent. When one comes up with a
good. structural design, it's practically impossible to make. Compromises are called
for. The most positive method of compromising would be to shorten the tubes, With
that goes the volume.

It is not my intention to detract from the idea, It is rather to point out that
there are more problems connected with this than with most centrifuge designs and
they will be felt in the cost. Despite this fact, we are working on the situation
for a very closely related problem in continuous flow centrifuging, and during the
early part of next year, we should be able to tell a great deal more about it. If,
in the meantime, you would jot down and send along to us your ideas of the
capabilities this rotor should have, it would certainly help to have them in front
of us.

WESTERN SALES aNd SERVICE OFFICE - BANK OF AMERICA BUILDING - BERKELEY 4, CALIFORNIA - ‘TELEPHONE: THORNWALL 8-0716
van Sorvall, Inc.

Dr. J. Lederberg =2~ 12/1/59

We're not much help to you for the present. No piece of equipment which we have,
or could easily make, will do for your purpose. Both our production and model-
making facilities are overtaxed for months to come. We hope to relieve this
situation by plant expansion next Sumer, but we just do not have the capacity
at the present time.

Your contact, in this matter, is certainly appreciated, JI am sure our work on
the bowl-type continuous flow will lay nicely the ground-work for the rotor you
hve in mind.

Sincerely yours,
IVAN SORVALL, INC.

Norman L, Christensen
Senior Vice-President