MASS FLOW ACCURACY FOR
GASSES
Some of the most important flavour
contributors to beer are fermentation
products such as esters, higher alcohols and
sulphur compounds. The concentrations of
these flavour compounds will be altered if the
growth characteristics of the yeast are less
than perfect.
Achieving the optimum O2 level in the wort
for each beer therefore is very important
in terms of product quality, so an effective
process to control the oxygen levels is
essential. Using a mass flow sensor to
establish the concentration of dissolved
solids, and total volume, coupled with a
mass flow controller to deliver the gas, is an
efficient starting point.
To improve the accuracy of the system even
more, the signal from a dissolved oxygen
(DO) probe in the fermenter vessel can
provide feedback to adjust the setpoint and
obtain the exact level of dissolved oxygen
required. This offers the opportunity to
maintain precise levels of dissolved oxygen
which have a major impact on the quality of
the final product.
PH IN WATER
Carbon dioxide (CO) is used to reduce the
pH of the water for a number of reasons.
Primarily, it is a gas that is easy to handle,
non-corrosive and its most appealing feature
is that it will not lower the pH of water
below 7.0. In addition, the only maintenance
required for the dosing system is to replenish
the gas cylinders periodically.
The control structure for this dosing system
needs to cope with variable flow as well
as decreasing gas pressure as the volume
in the cylinders deceases. Using a mass
flow controller that is calibrated for the
gas and delivers accurate measurements
independent of temperature and pressure, is
very important.
Oxygen levels can be accurately controlled during fermentation to ensure optimum product quality.
The CIP process can involve a range
of chemicals that are used to clean
and disinfect the equipment. The
concentration of these chemicals is
very important in achieving an effective
cleaning cycle without wasting expensive
materials. Also, using control systems
that are purely timer-based offers no
confidence in the effectiveness of the
process and also retains no meaningful
data, which may be required for regulatory
compliance.
By examining the temperature and the
conductivity of the cleaning fluid it is
possible to determine if too much energy
or too much chemical is being used. Any
reductions in energy consumption or raw
materials will have a beneficial effect on
operational costs. Working with sensor
manufacturers that have experience in this
application to create a more sophisticated
control and sensor feedback-loop system
can therefore offer many benefits.
Many will use a pH sensor after the dosing
point and use this information to adjust the
gas flow rate. This reactive process can be
optimised by adding a pH sensor to the input
side and using the readings from this sensor
to set the CO2 dosing rate. The second sensor
then acts as validation of the process setting.
This offers a quicker response to changes in
the pH levels at the input.
Correctly positioned pH sensors for example
can provide data on the effectiveness of
the process, while conductivity sensors
can provide a measure of contamination –
once this figure has reached almost zero,
the procedure can then be concluded with
minimum delays to production.
STREAMLINED PROCESSES
Ultimately, improving data collection,
interpretation and analysis can offer many
advantages. Working with experienced
process control manufacturers, such as
Bürkert, can yield benefits across the
board. From designing new installations to
improving the efficiency and effectiveness of
existing equipment, getting the right sensor
in the right place will have a significant
impact.
Process optimisation is primarily about
acquiring the correct data and using it
as effectively as possible. This requires
experience in the application as well as
with the equipment itself to ensure a cost-
effective and reliable installation. Bürkert
has over 100,000 catalogue items, including
cutting-edge flow measurement equipment
that can also provide mass flow data.
This expertise in manufacturing and
expansive knowledge of numerous
applications helps customers to reduce
operating costs, improve productivity and
ensure compliance with regulatory bodies
where necessary.
OPTIMISED CLEANING
For those working in hygienic applications,
clean-in-place (CIP) is a very important
process that maintains the cleanliness
of equipment. Using a combination of
chemicals, water and heat, the process offers
a very efficient method of cleaning vessels
and pipework without dismantling them.
However, time taken for cleaning is time
lost from production, so this needs to be
kept to a minimum whilst also ensuring that
the process has been effective. Optimising
the control of CIP reduces costs as well as
minimising chemical usage and improving
productivity.
About BURKERT
Burkert Fluid Control Systems is one of
the leading manufacturers of control
and measuring systems for fluids
and gases. The products have a wide
variety of applications and are used
by breweries and laboratories as well
as in medical engineering and space
technology. The company employs over
2,500 people and has a comprehensive
network of branches in 36 countries
world-wide.
Comprehensive process control installations
can deliver considerable savings.
www.burkert.co.uk
Issue 38 PECM
119