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Les langues disponibles
Les langues disponibles
Geology
Seismograph scale model
Réf :
507 035
ENGLISH
4 Use
4.1 Preliminary adjustments
The degree of freedom of the seismograph in relation to the frame depends on
several parameters, some of which are antagonistic.
The adjustment levels are as follows:
1. Positioning of the ring (10) on the rod (5): a position higher or lower than a
simple alignment creates a tension increasing solidarity between the weight
and the frame.
2. Tightening the ring retention screw (10): if the screw is over-tightened the
effect is identical to the first by linking the weight to the frame by the elastic
link on the suspension rod (9); the opposite effect of the screw being loose
releases the weight.
3. Friction of the pencil or felt-tip pen point: positioning and retention of the
pencil on the mass is performed using the screw (8). The ideal position
consists in reducing insofar as possible, friction on the paper while
maintaining sufficient pressure to allow recording.
When the weight is released from its attachment on the rod, friction of the
pencil on the paper reduces the independence of the weight in relation to the
instrument support.
This effect can be compensated by increasing the
retaining force, that is the weight/frame link by adjusting parameters 1 and 2.
Correct adjustment of these three parameters ensures optimum performance
of the seismograph, that is, mechanical independence in relation to any
shaking of the frame and at the same time, an accurate recording.
4.2 Operation
Place the seismograph on a table.
The shock waves of the earthquake are simulated, with printing out of
repeated shakes of the table, or direct shaking of the base of the scale model.
The orientation must be perpendicular to the direction of unwinding of the
paper.
During this period, a second person pulls the strip of paper to allow recording
of the seismograph.
If necessary, readjust as described in the previous paragraph.
5 Maintenance and storage
The seismograph scale model does not require any specific maintenance.
Replace the paper roll as follows (refer to the assembly diagram):
- On one of the sides, loosen the screw (13) located at the end of the axis of
rotation of the roll then remove the screws (14) and the two nuts accessible
under the instrument base.
- Remove the empty roll and replace by new one.
- Reassemble the support upright and tighten the side screw in the axis of
rotation.
For storage in a minimum space, the weight of the seismograph can be
removed as well as the support rod which can then be stored horizontally.
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