| Technical Description
A disc centrifuge can be used to separate mixtures of non-inter-soluble liquids.
emulsion to be separated is prepared in a stirred tank. Water/oil is
recommended for use as the emulsion. A stirring machine with a speed
control mixes the two liquid phases. In the course of the mixing
process the oil droplets are distributed ever more finely in the water.
When the droplet sizes are smaller the emulsion remains stable for
A pump delivers the emulsion up into the centre of the
rotating centrifuge. The emulsion is delivered by way of the
distributor base via riser ducts into the disc intermediate chambers.
The driving force of the separation process is centrifugal force. It
ensures that the specifically heavier liquid particles (water) are
drawn more strongly towards the outside than the specifically lighter
liquid particles (oil). The settling distance and time are shortened by
the disc arrangement set at an oblique angle to the field of
acceleration. On the underside of the rotating discs the specifically
heavier portion of the emulsion moves downwards and outwards. The
lighter portion flows inwards on the top side of the discs. The
separated liquids exit the centrifuge by way of outlets and can be
collected in tanks.
The rotation speed of the centrifuge can be
adjusted by way of a potentiometer. A valve is used to adjust the flow
rate of the emulsion due to be separated.
Various types of stirrer
are available to perform the stirring. A photometer is recommended for
analysis of the separated fractions.
The operating and service
instructions form the basis for learning how to perform an extensive
range of maintenance and inspection operations on the centrifuge.
Learning Objectives / Experiments
- Production of stable emulsions with different types of stirrer
- Learning the fundamental principle of disc centrifuges
- Influence of rotation speed and feed flow rate on separation result
- Characteristic of concentration of the light phase in the stirred tank over time (with photometer)
- Startup/shutdown and operation of a disc centrifuge
* Continuous separation of emulsions
* Maintenance and inspection exercises possible
* Practical experiments on a laboratory scale