Micromeritics 1305 Operator's Manual page 27

Model 1305 MultiVolume Pycnometer
Calibration Volume
Sample Chamber Cap
and Sealing O-ring
Pressure transducer
Jun 99
Four precision balls (volumes) are supplied with the
instrument to be used as high accuracy calibration
standards.
•
3
one 2.4250-cm ball of 0.6563-in. diameter for use
3
with the 5-cm sample volume range
•
3
one 16.758-cm ball of 1.2500-in. diameter for use
3
with the 35-cm range
•
3
two 25.49-cm balls (50.97-cm
diameter for use with the 150-cm
These volumes should be kept clean and maintained
as near the temperature of the instrument as possible
while in use.
Permits opening and closing of the sample chamber
with volume variations held to the microliter or less
range. The flat surface of the sealing plug mates with
a matching flat of the lip of the sample cup to pro-
vide a precise metal-to-metal stop. These surfaces
must be kept scrupulously free of particles, especially
3
with the 5-cm range, if the best instrument perform-
ance is to be achieved. The sealing plug is fitted with
a 2 x 1-7/8 x 1/16-in. Buna-N
the seal. This o-ring should be coated with a thin
layer of vacuum grease. It and all the surfaces it
touches or wipes must be maintained free of particles.
Two spare o-rings are included in the accessory kit.
The pressure transducer is a 25-psig unit of ±0.1% of
full scale accuracy. It is used only up to 20 psig in
the instrument. It will indicate vacuum down to about
-5 psig before showing a constant reading. Even
though it will not indicate vacuum below -5 psig, it is
not harmed by application of high vacuums. It is lo-
cated in the electronics enclosure on the other side of
the wall from the filter assembly. This transducer type
has been chosen for its excellent linearity, a factor es-
sential to the accurate operation of the Model 1305
MultiVolume Pycnometer.
Controls and Components
3
total) of 1.4375-in.
3
range.
TM
o-ring which makes
3-5