Function
The displacer rod, which is attached to a
measuring spring using a chain, immerses
into the liquid and is subject to a buoyant
force proportional to the mass of the displaced
liquid.
Every change in the weight of the rod corresponds
to a change in the length of the
spring and is therefore a measure of the
liquid level. The longitudinal expansion of
the spring, i.e. the travel of the rod, will be
transmitted from the measuring space to the
indicator unit by means of a magnetic coupling.
The basic version of the indicator unit
consists of a scale with a pointer for displaying
the liquid level. As an option, the indicator
unit may be equipped with electrical
transmitters for remote display or with limit
switches.
If the device cannot be installed from above,
because, for example, a stirrer is mounted in
the container, a special displacement vessel
is available for lateral installation.
Since the buoyancy of the displacer rod
depends on the density of the measured
medium, it must have been designed for the
specific liquid to be measured.