Reliable metering technology:
Metering Technology You Can Trust
The proper recording of measurements is the basic prerequisite for
optimising operating processes
Numbers are important! Figures accompany us throughout our daily
professional and private lives. Expressing production processes in figures is
not only a matter for engineers; modern quality management and controlling
procedures too make use of significant indicators in order to evaluate
operations in a company - the term "balanced scorecard", for example, is a
buzzword denoting an approach that helps to describe the effectiveness of
corporate strategies. Even if the ultimate indicator of a company’s success or
failure is the profit and loss account produced by the finance department, the
ways in which these final figures are arrived at must be as transparent and
understandable as possible. And for this to be achieved, all areas of an
operation, or as many as possible, need to be depicted effectively and
objectively, in order to make it possible for them to be evaluated. Within
production processes, however, it is physical and analytical metering
technology that offers a clear and objective instrument by which individual
sub-processes can be represented.
When decisions have to be taken on the scope and type of the metering
technology to be deployed in an operation, reliability is not the only
essential factor: the information that the equipment can provide on the
effectiveness and efficiency of the process is equally important. In the field
of modern process instrumentation, the work put into the further development of
systems and equipment must be guided by the precise requirements of the
application concerned. The constant dialogue between the vendor and the
customer and the intermeshing of equipment and application are essential
factors in the constant further development and improvement of metering systems
and devices. The diversity of process parameters that can be measured is
constantly being extended. Whereas 30 years or so ago, the basic
instrumentation of process plant in the food industry consisted only of the
thermometer and the manometer, flow metering and the measurement of ingredients
are nowadays often an integral part of modern manufacturing systems.
The
measurement of such parameters as conductivity, turbidity, density, speed of
sound, colour, filling level etc. has become state-of-the-art in production
process technology. Analytical processes such as the determination of
ingredients in complex blends (for example alcohol in liqueurs) or the counting
of yeast cells in fermentation products are also making the leap out of the
laboratory and into process technology. Infrared measuring techniques and a
variety of other forms of spectrometric technology still have considerable
innovative potential for industrial applications in the future.
Process indicators save money
If a manufacturing process is to be optimised by the installation of
appropriate control or regulating devices, the principle still applies, as it
always has, that before these parameters can be influenced it naturally has to
be possible for them to be recorded reliably and precisely. In the case of the
thermal treatment of a beverage, for example, not only temperature but also,
amongst other things, dwell time are important influencing factors. A combined
measuring unit for temperature and flow which determines the relevant
measurement values and at the same time can carry out the necessary regulation
measures fully automatically is just the solution needed for this process
requirement.
Right from its early days, GEA Diessel’s strategic orientation
has been towards “niche applications” in metering technology. The IZM-T™, for
example, which is based on the electromagnetic flow meter principle, offers
this combination of measurement functions, which also has many applications
where quantities have to be officially registered. These measuring devices can
be installed on mobile trolleys for peripatetic use, offering the advantage
that the metering technology can be used at practically any point in the plant.
If the measurement and control elements such as butterfly valves or other types
of control valve are driven by electric motors, the operator need provide no
other form of supply connection than an electric socket.
Mobile volumetric metering unit for automatic filling with
print-out of an official voucher
The fully automated and precise filling of containers, tankers or other
transportation vessels saves time and reduces product waste. Thus these devices
demonstrably save money. GEA Diessel offers numerous different versions adapted
to the customer’s specific requirements. Mass flow meters operating on the
Coriolis principle furnish a number of measurements at the same time: the
density, temperature, flow and volume of liquids and gases can be determined,
recorded and analysed simultaneously. In the case of mixtures that consist of
only two components, such as sugar solution, this data is already enough to
allow the concentration of the solution to be calculated, and thus enables an
indicator of the degree of efficiency within the production train to be
provided at any time. In breweries, the yield of finished beer produced from
the quantity of malt employed can be determined in a similar manner.
The
disproportionate rise in the cost of energy makes it more and more necessary to
constantly measure and monitor figures such as actual consumption per unit of
output (e.g. energy costs per hectolitre of beer), so that action can be taken
immediately if there is any marked deterioration in the efficiency of any
individual stage in production. The design of typical GEA Diessel modules for
beverage production such as water
deaeration systems (DIOX™ und VARIDOX™), continuous blending devices (DICON™) or carbonation systems (DICAR™) is
constantly monitored with a view to optimising consumption data. The quality of
the metering equipment used is of crucial importance in this.
VARIDOX™ water deaeration equipment
with integrated cooling
Maximum process reliability
The reliability of today’s meters reflects, amongst other things, the high
quality of both the electronic and the mechanical components. Years ago, a
metering device was typically expected to have a service life of seven years.
Thanks to constant development and improvement, this figure is now far
exceeded, e.g. in the case of electromagnetic flow meters. Mechanical metering
systems naturally require periodic servicing, but here too, the use of new
materials has led to a marked improvement. The introduction of sophisticated
modern materials has, for example, almost doubled the life expectancy of the DI-TRACO™ CO2 measuring
system.
Should any internal defects nevertheless occur, self-monitoring
mechanisms in the metering system are already able to identify and report
numerous possible malfunctions, so that the operator can react immediately and
prevent the production of faulty batches of product, which is expensive. It is
however important that either the equipment should be so designed as to allow
for production to be continued manually, or else that spare parts to replace
critical components should be available at short notice.
Since equipment
outages can have very serious consequences for highly sensitive processes, GEA
Diessel offers production units with enhanced redundancy, i.e. spare components
ready to take over a function if required.
In the case of continuous
blending devices such as DICON™, for example, there is combined regulation of
proportions and concentrations. Plausible limit values decide whether
individual measured results are tolerable. Atypical deviations are immediately
reported to the operator, who is then able, after a short check, to switch over
temporarily to the alternative metering equipment.
So-called “twin systems”,
for their part, virtually manage their functionality themselves. Here,
everything in the system is provided in tandem and operated in “master and
slave" mode. Generally speaking, the machine operates using the measurement
values furnished by the master. But it is also possible to take an average
value from the "master" and "slave" figures, the individual values being
monitored to see that they remain within the plausibility limits.
If there
should be any breakdown, the device switches over automatically from the master
to the slave system, ensuring that production can continue; this ensures
reliable operation even during the night shift.
Summary
The recording of measurement values is a basic prerequisite for being able
to take action to optimise production processes. GEA Diessel has been producing
a variety of metering devices for many years and makes use of different
measuring systems in its equipment for the food and beverage industry. For very
sensitive areas within production, measurement and control systems with
multiple redundancy, known at GEA Diessel as “twin” systems, may well prove to
be worth while in the long term despite higher procurement costs.
The author:
Hermann Hartmann, Dipl. Phys.,
Head of Metering and Data Technology at GEA Diessel
Published in: food Marketing & Technology, June
2008
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