Decanter centrifuges
for laboratory & pilot plant
ModelMD 60MD 80
Throughput: 1 - 100 l/h
Max. acceleration: 4,400 g
Lemitec decanter centrifuges of the MD series
were developed specifically as two-phase
decanter centrifuges for use in laboratories and
pilot plants to enable small quantities of
products to be processed at rates of between
1 L/h to 100 L/h in a continuous separation
operation. The minimum throughputs of
industrial decanter centrifuges are generally far
greater than the throughputs required for the
quantities of products available in research
laboratories. In the past, the processing stage
of continuous separation therefore frequently
had to be simulated with alternative batch-wise
separation methods.
Applications
Lemitec decanter centrifuges are typically used
in the food and fermentation industries, the
chemical and pharmaceutical industries and in
biotechnology. In addition to their use in R&D
departments, Lemitec decanter centrifuges
have also been successfully used over long
periods in the production of high-quality prod-
ucts requiring material flows of less than 100
L/h.
Lemitec decanter centrifuges can also be used
as measuring instruments to obtain data on the
flow properties of individual product phases.
The flow behaviour of the product stream and
the change in the torque between the bowl and
the scroll are displayed on the control panel of
the decanter centrifuge as a function of the
power consumption of the drive motors and
recorded, thus enabling the flow behaviour to
be evaluated for the purpose of modelling de-
canter applications.
Operating principle
The operating principle of decanter centrifuges
is quite simple and has been known for over a
century. The suspension to be separated is
pumped into the bowl through an inlet tube
(feed) and accelerated.
Separation process
The bowl comprises a cylindrical and a conical
section and rotates at a speed appropriate for
the separation operation. Centrifugal force
causes the solids present in the suspension to
be deposited on the wall of the bowl.
Solids discharge
The scroll, which has the same
cylindrical/conical shape as the bowl, rotates at
a slightly higher speed (differential speed) than
the bowl. This causes the separated solids to
be conveyed towards the narrow conical end of
the bowl where they are expelled through
outlets and discharged. The extent to which the
solids are dewatered depends, amongst other
things, on the length of time they are exposed
to the centrifugal force in the bowl. The time
taken for the solids to be conveyed through the
bowl can be set as appropriate for the type of
separation operation by altering the differential
speed.
Lemitec MD 60 Decanter centrifuge
Lemitec MD 60 / MD 80 Decanter centrifuges
Throughput
1 to 100 L/h
Liquid discharge
A weir disc that can be set
exactly as required is fitted at
the end of the cylindrical
section of the bowl. The
clarified liquid flows along the
scroll thread to the cylindrical
end of the bowl and out over
the weir plate, after which it
is collected in the casing and
discharged. The depth of the
clarified liquid in the bowl can
be adjusted to exactly the
level required by inserting different weir discs.
All Lemitec decanter centrifuges of the new MD
product series are fitted with a centripetal
pump for discharging the clarified liquid. It is
now possible to discharge the clarified liquid
under pressure.
Control
The decanter centrifuge is controlled and
monitored by means of a modern touch screen
that also displays all important process
parameters at a glance. The decanter
centrifuge can be incorporated into
a process control system via a
variety of interfaces.
The acceleration (g) and the diffe-
rential speed are also fully adjusta-
ble during operation and can be
altered to suit the product beha-
viour.
Drive
The bowl and scroll are driven by two separate-
ly controlled servo-motors that are connected
electronically.
This means that there is no need to use a me-
chanical gear unit. The differential speed can
therefore be set with a high degree
of precision, irrespective of the range of
speeds. The minimum differential speed is as
low as 1 rpm. As the bowl and scroll are not
mechanically connected, Lemitec decanter
centrifuges may also be used to determine the
optimum or maximum separation parameters of
individual products. The drive is switched off
electrically without damaging the machine if the
permitted operating parameters are exceeded,
for example due to an excessive amount of
torque between the bowl and the scroll.
Construction
All Lemitec decanter centrifuges have been
designed to be compact and simple to operate
as well as ensuring functionality and taking full
account of users' needs. The number of com-
ponents has been kept to a minimum, as has
the equipment required for assembly. The set-
up times have thus been considerably reduced
and the changeover from one product to anoth-
er, including the time required for thorough
Section view of a decanter centrifuge
cleaning of the centrifuges, can be completed
in just thirty minutes. Thanks to the fact that
Lemitec centrifuges are straightforward to oper-
ate, there has also been a great reduction in the
time needed to train staff how to use them. The
additional items of equipment provided also
facilitate the day-to-day operation of the centri-
fuges.
All ceramic bearings
Lemitec decanter centrifuges may also be fitted
with all-ceramic bearings. Unlike conventional
bearings, all-ceramic bearings do not require
any greasing or oiling but can be lubricated with
water instead. The decanter centrifuges can
thus be completely sterilised with steam as well
as operated under sterile conditions without a
great deal of extra effort.
Advantages
Universal decanter centrifuge
Quick product change – under 30
minutes
Modern control panel and reduced
parts mean easy operation
Compact space saving design
Use under sterile conditions possible
Technical data
MD 60 MD 80
Throughput
Bowl
Internal diameter 60 mm 80 mm
Slenderness ratio (L/D) 3.75 3.85
Maximum acceleration 3,300 x g 4,400 x g
Maximum speed 10,000 rpm 10,000 rpm
Differential speed 1 - 200 rpm 1 - 200 rpm
Motor rating 2 x 1.2 kW 2 x 3.5 kW
Material used for components in contact with the product
1.4571 1.4571
Additional items of equipment and tools needed to operate a Lemitec decanter centrifuge
Completely
sterilisable
Product changeover
in just 30 minutes
Lemitec GmbH
Rieppelstrasse 6
D-13629 Berlin
Fon +49 (0) 30 - 33 09 15 40
Fax +49 (0) 30 - 33 09 15 41
E-Mail [email protected]
Internet www.lemitec.com
Decanter throughput 1 - 30 L/h 5 - 100 L/h
Dimension and weights
80 kg 125 kg
Control unit (cabinet) 300 x 400 x 700 mm 400 x 500 x 970 mm
24 kg 47 kg
Decanter 700 x 300 x 550 mm 1,000 x 350 x 550 mm