10
2.
FEATURES
OF
THE
turret
6
A.
General
Description
The
turret
6
has
a
rotating,
temperature
‐
controlled,
metal
cuvette
tower
which
holds
up
to
six
cuvettes.
An
insulating
cover
of
urethane
plastic
encloses
the
cuvette
tower,
providing
thermal
insulation.
A
floor
is
attached
to
the
bottom
of
the
tower,
and
the
rotating
body
of
the
holder
contains
a
Peltier
element
sandwiched
between
this
floor
and
a
brass
heat
exchanger.
Water
flows
through
the
heat
exchanger
to
draw
off
heat
generated
when
the
temperate
of
the
cuvette
tower
is
lowered.
Figure
5.
turret
6
with
a
section
cut
away
to
show
the
optic
access
to
one
of
the
cuvettes
A
miniature
stepping
motor
resides
under
each
cuvette
to
drive
rotating
magnet.
Dry
gas
enters
a
1/16
‐
inch
hose
barb
on
the
front
of
the
instrument
and
is
carried
through
a
manifold
in
the
floor
of
the
turret
to
small
holes
on
the
bottom
of
the
18
cuvette
windows.
This
flow
of
gas
will
keep
the
windows
free
of
condensation
when
working
below
the
dew
point
temperature.
The
rotating
body
is
mounted
on
a
large
precision
bearing
and
rotated
via
gears,
using
the
external
Vexta
stepping
motor
(not
visible
in
this
view).
Two
wires
exit
below
the
Vexta
stepping
motor.
One
conducts
the
drive
currents
for
the
stepping
motor
and
Peltier
unit.
The
other
conducts
the
sensor
lines.
The
two
brass
1/8
‐
inch
hose
barbs
for
water
provide
access
to
the
heat
exchanger.
A
1/16
‐
inch
brass
hose
barb
is
used
for
the
dry
gas.
CAUTION:
Accidently
attaching
a
water
line
to
the
dry
gas
barb
will
severely
damage
the
instrument!
Attach
the
lines
with
care.
