VWR Collection Laboratory Equipment - page 45

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2. Temperature needs:
Temperature uniformity refers to the consistency of the temperature across the
top plate. Each top plate material has its pros and cons. Ceramic top plates are
more chemical resistant, heat up very quickly, and are easy to clean. The white
reflective surface aids in viewing the sample. However; ceramic tops are subject
to thermal shock. Heating of metallic vessels should be avoided. The edges of
a ceramic top plate may not be a hot as the center where the heating element is
located. Aluminum top plates offer a more uniform heating surface, will not crack or
chip but are more susceptible to corrosion and more difficult to clean.
3. Sample size:
The size or volume of your sample is another important factor to consider when
selecting a hotplate or stirrer. Always consider the largest sample that you may
be working with and look for one that can handle that capacity. The capacities
listed are based on water. A viscous sample will weigh more than water.
4. Viscosity:
Sample viscosity plays a role in selecting a stirrer. The magnetic coupling strength
is a factor in determining which size stirrer to choose. The right drive magnet and
stir bar combination is needed to efficiently stir the sample. Variables such as
sample size or weight and top plate size dictate which stirrer will work best. The
stir bar size and shape, the distance between the drive magnet and the stir bar,
vessel shape and size, speed and viscosity also must be considered. The more
viscous the sample, the greater magnetic coupling strength needed.
How to Select a Hotplate/Stirrer
VWR
®
Hotplate/Stirrer Selection Guide
VWR
®
HOTPLATES/STIRRERS
Hotplates, Stirrers
& Hotplate-Stirrers
Basic Mini
High Volume Stirrer
Standard / Advanced
Large Capacity Stirrer
Model 1000 / Model 2000
Advanced
Multi-Position Stirrer
Standard / Advanced
Slow Speed Stirrer
4 Position / 10L
Standard/Advanced
Slow Speed Stirrer
1 Position
Standard/Advanced
4.5” Diameter
12.5 x 11”
21.25 x 25”
12.5 x 11”
12.5 x 11”
7 x 7”
6.5 x 5.75 x 4.75”
(16.5 x 14.6 x 12.1cm)
17 x 11 x 3.8”
(43.2 x 27.9 x 9.7cm)
28. x 26.6 x 5.25”
(71.1 x 67.6 x 13.3cm)
17 x 11 x 4”
(43.2 x 27.9 x 10.2cm)
17 x 11 x 4”
(43.2 x 27.9 x 10.2cm)
21.1 x 8.5 x 3.5”
(53.6 x 21.6 x 8.9cm)
N/A
to 400°C
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
100 to 1200rpm
60 to 1400rpm
100 to 1800 rpm
60 to 1400rpm
1 to 150rpm
1 to 150rpm
± 2%
± 2%
± 2%
± 2%
± 1%
± 1%
N/A
1 second to 160 hours
1 second to 160 hours
1 second to 160 hours
1 second to 160 hours
1 second to 160 hours
1000mL
25L
100L / 200L
1L
1L / 10L
2L
4.5lbs (2kg)
14.6lbs (6.6kg)
63lbs (28.6kg)
14.75lbs (6.69kg)
14.5lbs (6.6kg)
8.8lbs (4kg)
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