8
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Hermetic sealing
• The microswitch is fi lled with inert gas (nitrogen-hydrogen mixture), the internal pressure being 1 bar.
• The hermetic sealing (membrane-cap - cap-base) is achieved with a continuous seam welding bead.
• 1 x 10-8 atm cm3/s
6
5
4
3
2
1
-1
-2
∆FC (N) Increase in operating force
P (mm Hg)
θ°C
600
+ 250° C
0mm Hg
400
760
150° C
50° C
25° C
-50° C
200 150 100 50 0 200 400 7600
DISTINCTIVE CHARACTERISTICS
8
7
6
5
4
3
2
0 0.27 0.28 0.29 0.30 0.31 0.32 0.33 0.34 0.35
F.daN
Total
Tolerated overtravel
forces
travel
in mm
Mechanical strength
No abrupt increase in the total travel of the
device is noted under rising overtravel forces
of up to 80 N. On return to a normal overtravel
force of 20 N after these measurements have
been carried out on one and the same device, the
total travel will be observed to have varied only
very little (low permanent set).
The device can be damaged if the overtravel
force is pushed up to 150 N.
Change in operating force as a function of
ambient temperature and pressure.
The force values of our hermetically sealed
microswitches are infl uenced by ambient pressure
and temperature; we give the value, for the base
cell, for the increase in operating force (∆ OF) as a
function of these two parameters.
The characteristics are stated for normal
temperature (23°C) and atmospheric pressure at
sea level (760 mm Hg).
Our hermetically sealed microswitches can be used
from atmospheric pressure to absolute vacuum;
some variants allow use at higher pressures.
Reliability of characteristics
Below are two test extracts showing the stability of the essential characteristics over time and as a function of
temperature.
F
Operating force T°=150°C
0.5 N0.5 N0.02 mm
Release force
Rest position
5 days
Release position
Operating position
Overtravel position
Time
Travels and forces
Change in the characteristics
concerned under a constant load of
25 Newtons applied to the operating
device.