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4
Construction and function
Construction:
The measuring tube with its earthing sleeves and electrodes
passes through the sensor housing and forms the external
process connection of the FMG90.
A magnetic field for the measurement process is generated inside
the sensor housing, which also contains the sensor and signal
conditioning circuitry.
The two stainless steel electrodes are located in the middle of the
measuring tube between the earthing sleeves. The FMG90 does
not need any moving parts to make measurements. The inside of
the measuring tube is completely open, allowing the fluid to flow
unhindered through the measuring tube.
Function:
The magnetic inductive flow sensor functions according to the induction principle:
The measuring tube is located in a magnetic field (B). If
an electrically conductive medium (V) flows through the
measuring tube and, therefore, at right angles to the
magnetic field, a voltage (U) which is proportional to
the mean flow velocity will be induced in the medium
and subsequently picked up by the two electrodes.
5
Installation
Before installing, check that
the wetted materials of the device are suitable for the media being used (see Materials
Table "10.1").
the equipment is switched off and is in a safe and de-energised state.
the equipment is depressurised and has cooled down.
SUITABLE TOOLS:
Use only suitable tools of the correct size.