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eoretical bed level based on the
calculation of the average density
of a constant height using a
hydrostatic pressure sensor
Submerged ultrasound sludge
blanket transducer to sense
re ections from the solid bed
Turbidity sensor, either at a xed
height or attached to a motorised
cable spool.
Buoyancy based
electromechanical system
mechanism allowing the unit to be
positioned at a xed height or attached to a
extracted, cleaned and validated without
motorised cable spool determines the
shutting down the process. e insertion
turbidity of the process water. Used in a
length of the sensor mechanism can be
xed height system, it can be used to
varied to match the thickness of the tank
initiate the reduction of the in ow rate
wall and to ensure optimal sensor depth
should turbidity levels increase. On a
once inserted in the tank. High quality
motorised cable spool, it can provide a
assemblies are speci cally designed to
turbidity pro le to the operator. is
prevent operator injuries during the
measurement is targeted at turbidity
validation process. Due to the requirement
pro ling as well as bed-level detection. If
of the extension of the sensor into the
only bed level measurement is required,
process in this style of transmitter, the use
then the buoyancy principle is more cost
of a ceramic sensor avoids long oil lled
effective.
capillaries between the sensors and
e 'buoyancy based electromechanical
transmitter that are used in metal type
system' uses a sensing weight which is
sensors. is means a more robust solution
lowered on a measuring tape into the
with improved long term accuracy and
thickener to detect the bed level. Typically,
stability.
the sensing weight is a light, hollow
In processes with slow and predictable
container lled with the bed level material.
settling behaviours, using only the
When the container is lowered, it sinks in
hydrostatic pressure technique can be
the water but ' oats' when it reaches the
adequate. However processes prone to
bed. At t