MEASUREMENT & MONITORING
STATE-OF-THE-ART
KOBOLD
THE WORLD’S SMALLEST DUAL-TUBE
CORIOLIS MASS FLOW METER: HIGH
PRECISION MEASUREMENTS WITHIN 150 MM
Due to the weight influence of sensor coils,
for the measurement of very small flow-
rates it is common practice to use single
tube Coriolis flow meters. The sensor coils
of dual-tube Coriolis sensors are mounted
onto one of the two measuring tubes, thus
having, by very small tube diameters, a
significant weight influence on the tube on
which they are mounted.
Therefore, the influence of the sensor coils
on the measurement results increases by
decreasing tube diameter. For this reason
single tubes are often favoured for the
measurement of very small flow‑rates,
where the coils are mounted to the chassis
and not on the tube. However, with the use
of just one measuring tube the influence
of external interferences increases
dramatically. To reduce this sensitivity
and at the same time delivering accurate
measurements at very small flow rates,
Heinrichs Messtechnik has developed the
dual-tube Coriolis principle to a new level.
In this new state-of-the-art technologie,
the sensor coils are no longer mounted
onto the tubes, but rather between them,
thus freeing the measuring tubes from the
influence of the coils weight allowing for
extremly small tube diameters in dual-tube
design.
The result is the world’s smallest dual-
tube Coriolis Mass flow-meter: The high
Performance Coriolis (HPC). With an
installation length of just 150 mm it is
now possible to achieve high accuracy
measurements with deviations of just ± 0.1
percent. Furthermore, the sensor shows
insensitivity to temperatures of up to
180 °C, to pressures of up to 600 bar as well
as to strong vibrations.
“Market observations have revealed an
open gap in the measurement of small
flow rates”, explains Frank Schramm,
the managing director of Heinrichs
Messtechnik GmbH. The current problem
is that the state-of-the-art stipulates
the use of dual-tube technology, where
the magnets are mounted to one tube,
the exciter and sensor coils to the other.
However, for very small flow rates this
principal has a decisive limit. For example,
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PECM Issue 40
Heinrichs Messtechnik GmbH developed the smallest dual-tubed-Coriolis-Mass-Flowmeter in
the world: The High Performance Coriolis (HPC). With an installation length of just 150 mm
high accuracy measurements are achieved with deviations of just ± 0.1 percent
where extremely small flow rates demands
a tube diameter of just 1 mm, the vibrating
behavior of the coils weight can influence
the measurement results significantly.
“Therefore it is common practice to use
one tube systems for these applications,
in which the coils are mounted to the
chassis of the sensor. This system has the
decisive disadvantage in that the second
tube, which also serves as a measurement
reference, is omitted, requiring that the
sensor coils be mounted on to the chassis
of the enclosure making the sensor
more susceptible to vibrations and other
disturbances.
For this reason, Heinrichs Messtechnik
GmbH has set as its objective, the
development of a high precision, shock
resistant Coriolis Mass Flow Meter.
Emerged is the High Precision Coriolis –
short HPC – with its installation length of
just 150 mm the smallest Coriolis mass
flow meter in dual-tube design.
REDUCING DISTURBANCE
INFLUENCES BY POSITIONING
THE SENSOR COILS BETWEEN
THE MEASURING TUBES
“Due to the sensitivity single tube Coriolis
sensors, a costly mechanical decoupling
is often required, rendering them
inappropriate for many applications. Our
quest was therefore to find a means of
unifying a dual tube design with very
small diameter tubes”, explained Schramm.