Separator's Digest - GEA Westfalia Separator Group

Central processing
of raw milk
Müllermilch decided to change over the
operations with a daily milk processing
quantity of approx. 400 t raw milk
completely to the production of H-milk.
because the plan involves the use of several
UHt heating installations, the most costeffective
solution for purifying and
standardizing the milk was to use a cold
milk skimmer including a standardizing
system with sufficiently large capacity
for central processing of the raw milk. In
order to be able to produce skim milk
with a minimum fat content, the plan was
also for a milk pre-heater installation to
be integrated, because the residual fat
content in skim milk is very temperaturedependent.
the order for a milk treatment installation
with a cold milk separator type MSe 500
with a capacity of max. 35,000 l / h raw milk
and a Gea Westfalia Separator standomat
MC for milk and cream standardization was
placed by Müllermilch, following extensive
preparations, with Gea Westfalia Separator
in oelde via the agent Gea Westfalia
Separator CZ s . r .o. because the intention
was to minimise the installation and
commissioning time, the focus was on
complete pre-assembly in the oelde
plant. tried-and-tested components from
companies of the Gea Group were used
almost exclusively for the design of the
installation. accordingly, the pumps and
valves come from Gea tuchenhagen, and
the heat exchangers come from Gea
ecoflex.
Cold milk machine with
a fully hermetic bowl
the installation consists of a buffer tank
with a regulated feed. the milk which
comes from the raw milk tank is conveyed
by the feed pump through a plate
heat exchanger in which it can initially be
pre-heated in a regenerative section and
subsequently heated up to 15 °C in the
heating section with warm water. the warm
water is generated in a warm water circuit
by means of steam. of course, it is also
possible for the steam feed to be shut off
entirely and for the milk to be processed
cold.
the milk is fed into the separator, where it
is treated by means of centrifugal force and
separated into skim milk and cream. the
WeStFalIa Separator standomat MC aND MSe 500
The milk treatment plant incorporates, among other things, an MSE 500
cold milk separator and a Westfalia Separator standomat MC.
MSe 500 cold milk machine is a version with
a fully hermetic bowl. the slide-ring packings
in the feed and discharge are cooled with
water during the start-up and shut-down
phases; this extends the service life of the
packings. the density and temperature of
the cream are measured in the Gea Westfalia
Separator standomat MC; these data are
used to determine the fat content, and a
hygienic regulating valve is used to set the
desired concentration. a cream fat content
of up to 42 percent is possible. the process
control calculates the quantity of cream
required to achieve the defined milk fat
content. the excess cream is discharged via
a further regulating valve, and is fed into a
collecting tank; the remaining cream is
recycled back into the skim milk.
the excess cream is pumped from the
collecting tank by means of a cream
pump into the raw cream tank for
further processing. the temperature of the
standardised milk is lowered to less than
4 °C in the regenerative and the ice-water
cooling section of the plate heat exchanger.
the milk is then fed into the finished milk
tank, from where it is distributed to the UHt
installations.
Fully automatic cleaning
During the production process, which can
take 12 hours, fat may become deposited
on the disks. this fat is removed from
the separator by means of hot water
intermediate flushing. For this purpose,
product is displaced from the installation
with water, and the buffer tank is filled with
water. the temperature of the water in
GEA Westfalia Separator Process 15
Separator’s Digest 3 | 2008
the circuit is raised to 60 °C; the design of
the installation means that this process
takes only a few minutes. the hot water
circulates, and two partial ejections of the
bowl are carried out in order to remove all
remaining traces of fat. after this procedure
has been completed, the contents of
the installation are returned to production
temperature with ice-water, and milk
processing recommences. after the end of
production, a completely automatic cleaning
process is carried out by the central CIp
station of the dairy.
the entire installation is automated by
means of a C 7 automation unit from
Siemens with a local graphic display and
a keyboard. the installation control is
linked to the central control facility of the
dairy via a profibus, and communicates all
readings as well as valve and motor statuses
to the central control facility. the command
centre is responsible for operation and
visualisation.
the installation has been operating since
the end of 2007; the technical acceptance
procedure has already been completed, and
the installation is operating to the complete
satisfaction of the dairy.