HYDAC FILTER SYSTEMS GMBH
Appendix | A
MoWa OLS10-Z-x 4573340 en-us web
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1. Functional principle
By means of the magnetic field of the magnet – which is located on the
inside of the float housing – the reed contacts (protective gas contacts) ar-
ranged in the sliding tube are actuated according to the fill level required.
Depending on the type of contact (closing contact or opening contact), the
control circuit is opened or closed and a switch command is transmitted,
which is used for control purposes or signalling. If the device is equipped
with a temperature switch, the same function is triggered by this switch
when the particular temperature is reached.
2. Area of application
Float switches must only be used for fill level regulation or fill level
monitoring of liquid media. Fluids must not exhibit severe contamination
or contain coarse fragments and must not be subject to crystallisation.
It must be ensured that materials of the device that come into contact with
the media (sliding tube, float) have a sufficient level of chemical resistance
to the medium to be monitored.
3. Application in EX zone
Only devices that are explicitly designated as EX devices can be used in
EX zones. Float switches in an explosion-proof design are suitable for use
in zone 0 explosive gas atmospheres. Devices featuring the designation
Ex ia IIC T6 and EX ia IIIC T80°C are intended for use in normal ambient
temperatures and liquid temperatures up to 60°C; devices featuring the
designation Ex ia IIC T6...T4 and Ex ia IIIC T80°C...T125°C are intended
for use in increased temperatures up to 125°C. The maximum operating
temperature and the EX designation on the type plate must be observed.
Float switches in an explosion-proof design must only be connected to a
certified intrinsically safe supply circuit and evaluation circuit with maxi-
mum values of 30 V DC, 100 mA or 100 mW. The operating temperature
ranges can be found in the temperature class table and device specifica-
tions can be found on the type plate.
4. Mounting
When mounting the Reed-Control float switch, the type of mounting loca-
tion on site must correspond to the mechanical connection of the float
switch. The dimensions of the screw socket must be identical to the di-
mensions of the screw plug of the float switch. With regard to flange ty-
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