The whole development
phase took a mere 1.5
years. To achieve this short
development time Heinrichs
Messtechnik utilized the latest
simulation technology.
Instead of mounting the coils onto the tubes, the manufacturer chose to mount them onto a
PCB situated between the measuring tubes. By simultaneously doubling the number of pick-
up coils from two to four, the resolution is increased significantly.
Since the fundamental problem lies in the
weight of the coils, which when compared
with tube diameters of 1.5 mm or less
present a significant weight, Heinrichs
Messtechnik adopted the following
solution: The conventional approach of
mounting the coils onto the tubes was
abandoned in favour their mounting on
a printed circuit board mounted between
the tubes. This method also enables the
use of four sensor coils instead of two, as
is usually the case with dual-tube Coriolis,
providing a higher resolution.
On the measuring tubes themselves only
very light magnets are mounted, which,
with a weight of only 0.08g, have little to
no influence on the vibrating behavior of
the tubes.
Instead of conventional brazing, the
magnet holders are mounted onto the
tubes using a special laser-welding
technology. Utilizing this method,
Heinrichs Messtechnik aims at keeping
the production costs of the sensor to an
absolute minimum, it not only allows for a
stress‑free connection, but also eliminates
the time-consuming and elaborate process
of brazing in a vacuum oven.
INSENSITIVE TO EXTERNAL
INFLUENCES
Using the dual-tube design, the new HPC
displays extreme insensitivity towards
external influences, allowing for precise
measurements with a maximum deviation
of ± 0.1 Percent of the mean value and a
Zero-point stability between 0.001 and
0.005, making a mechanical decoupling
in most cases superfluous. Owing to the
measuring tubes high working frequency
of over 200 Hz, the coupling of installation
vibrations or similar oscillations into the
measuring system is prevented and so
with avoiding fault signals. A further
advantage in mounting the sensor coils
on a motionless PCB is the elimination of
open wiring within the sensor, as is the
case of standard commercially available
devices. This wiring often presents a
vulnerable weak point, since the wire and
its point of connection must vibration
continuously with the frequency of the
measuring tubes.
With the exception of the laser welded
measuring tubes, the HPC consists
essentially of a solid drilled and tapped
stainless steel block. Furthermore, the HPC
has been stripped of a splitter at the inflow
of the tubes, instead possessing a reservoir
– in which the process pressure distributes
the fluid exact into the measuring tubes,
hence preventing flow disturbances
generally caused by splitters. This
technique has the timesaving advantage
of one less component to weld as well as
one less potential material stress source.
The result is an extremely robust device
capable of withstanding temperatures
and pressures of up to 180 °C and 600 bar
respectively. “In principle, the device may
also be ordered with Hastelloy tubes and
other alloys”, added Schramm.
VARIABLE ASSEMBLY
CONCEPT
For flexible installations, different
constructive variations of the HPC are
available: Besides the traditional Inline
Version, which can be inserted directly into
the process line, there are three further
models available, which are suitable for
either wall mounting, by means of wall
brackets, or may simply be placed on
a table. “For our Table model there are
two available options: either with the
measuring pipes pointing downwards
below the supply line or pointing
upwards above the supply line. For the
measurement of gas, upward pointing
tubes are recommended to prevent any
issues with fluid collecting in the tubes.
The same also goes visa versa for the
measurement of fluids”, Schramm remarks.
Collectively, the devices are available in
three measuring ranges:
0–20, 0–50 and 0–160 kg/h. On request
other adaptations are also available, for
example, customer-specific enclosures,
connectors or interfaces. In particular for
the chemical and semiconductor industry,
fully-welded stainless steel enclosures are
also available.
RAPID DEVELOPMENT
SUCCESS WITH HIGH-END
SIMULATION
The whole development phase took
a mere 1.5 years. To achieve this short
development time, Heinrichs Messtechnik
utilized a state-of-the-art simulation
technology. “By these means the required
number of prototypes was drastically
reduced, reducing so with development
costs significantly”, Schramm says
contentedly. Furthermore, with the aid
of the simulation technology customer-
specific requirements can be captured
and individual solutions presented in the
shortest of time.
The HPC was presented for the first time
on the Hannover trade fair from 23rd to
the 27th of April, simultaneously being
the official launch of sales. Furthermore,
ATEX and IECEx approvals are also planned
as well as a patent registration of the
technology. Parallel to the launch of sales,
Heinrichs Messtechnik is also working
on a new miniaturized transmitter with
flexible interfaces, specially designed for
compatibility with the HPC.
www.kobold.com
Issue 40 PECM
147