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2. . . . . Description, technical data
Two precision-made glass syringes [
volume are attached to an acrylic carrier plate
of an anodised aluminium stand rod
plungers has a tray
1
for holding weights
ringes are linked by a connecting hose
form a closed system. An air inlet
drawn into the system. A safety cord prevents the small
plunger flying out of the cylinder. A rod
the base plate
upon which disc weights can be stacked
5
when not in use.
Volume of syringes:
Ratio of plunger
diameters:
Ratio of plunger masses
with tray:
Number of weights:
Mass of weights:
Base plate dimensions:
Total weight:
3. . . . . Operation
• Preparation: open the air inlet, pull out the large cyl-
inder to about the 20-30 ml mark then close the inlet
again.
3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com • Technical amendments are possible
,
] of differing
3
9
on top
2
. Each of the
4
. The sy-
bm
so that they
8
allows air to be
7
is included on
6
10 ml and 50 ml
10:3 (∅ 26.9 mm : 14.7 mm)
10:3
15
40 g each (approx.)
140 mm x 100 mm
1.2 kg
• Experiment procedure: first lay a weight onto the
small plunger. Next lay weights one by one on top of
the large plunger. When the fourth weight is laid on,
the plunger starts to descend.
• Thus when the weight ratio is about 1 : 3.5 ± 0.5
weights, the system is in equilibrium. This ratio is
confirmed by placing weights in the ratio of 2 : 7 (if
the plungers are very clean and weights precisely cen-
tered, the large plunger may start to descend). Equi-
librium is also apparent for a weight ratio of 3 : 10.
• During the course of an experiment, air gradually
seeps out since syringes that were entirely airtight
would not move at all. It may be necessary to let in
more air.
4. . . . . Storage and cleaning
• For the equipment to function perfectly, it is essen-
tial that the plungers and cylinders are free of any
grease or dust. Even fingerprints can affect the func-
tionality adversely. The equipment can be cleaned
using methylated spirits (caution: flammable!). If the
safety cord is removed to facilitate cleaning, it can be
replaced by any suitable strong nylon cord (e.g. but-
tonhole thread).
• The equipment should be stored in a dry, dust-free
location.
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