Thermo Scientific 11174729, Инструкция по эксплуатации

Страница: 21 / 66

Chapter 4
OPERATING PRINCIPALES
Thermo Fisher Scientific MR23i 4-1
Chapter 4
OPERATING
PRINCIPALES
DRIVE SYSTEM
The rotor is driven by a three phase asynchronous motor. The rotor
is situated in the centre of a virtually hermetically sealed and
armour plated centifugation chamber. A control system ensures the
correct drive speed.
The shape of the rotor is a primary load factor: a horizontal rotor
presents a greater load than a fixedangle rotor. The larger the dia-
meter of a rotor, with accessories, the greater the load, and the
lower the maximum r.p.m. The machine cannot spin the rotors at a
speed higher than that which they can resist mechanically.
Relative centrifugal force (RCF), at the circumference of a rotor
and bucket combination, is directly proportional to the square of the
speed (r.p.m.) and radius of the rotor.
Therefore, a greater r.p.m. and/or a larger radius produces a grea-
ter R.C.F. and increases the speed of separation of the sub-
stances.
SAFETY
INTERLOCK
SYSTEM
The Jouan MR23i is equipped with an interlock system that pre-
vents opening of the centrifuge lid when the rotor is spinning.
The centrifuge will not operate until the lid is closed and latched in
place. The lid remains latched until the rotor stops spinning.
When the rotor has stopped spinning, the stand-by screen will be
displayed. The lid cannot be opened while any screen showing live
and set values is displayed, nor if a fault screen showing a TIME
OUT is displayed.
Note If a power failure occurs, access to the samples in the centrifuge is
possible. For this it is necessary to use a special tool. Follow the lid
opening procedure (
Chapter 2: “INSTALLATION PROCEDURE”
Section “MANUAL LID UNLOCKING” ).
Perform bypass only under emergency conditions as the rotor
could still be rotating.
IMBALANCE
DETECTION
SYSTEM
The Jouan MR23i is equipped with an imbalance system that con-
tacts a switch when an unacceptable imbalance is present in the
rotor load. When it is activated the brake is applied immediately.