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 info@lemitec.com

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