- This is one of the best way we know to increase
efficiency in separation of different plastic materials.
- Hydrocyclone is a static device where flakes are
spinning into a tube by means of water flow created
by a pump.
- Separation occour because the two forces, centrifugal
and centripetal increase the difference of specific
- As simple as this.
for separation of plastic scraps||
- Hydrocyclones are widely
used for separation in plastic recycling.
- You surely
know the very common cyclone used everywhere.
hydrocyclone is nothing but a cyclone working with water and not with
Because of this, a little more attention should be paid to inlet speed
and outlet sizes because these parameters can change the performance of this
device but, the principle is just the same.
- Hydrocyclone uses the centrifugal force of water, spinning inside
the cylinder, to push heavier than 1 material to the side while less than 1
material gets centripetal force and it stays in the centre, going to another
The spinning of water increases the difference of
Theory is very good indeed; let's go to practice.
the maximum available speed we'll need a high pressure water pump, and this is
easily available but, and it is a big but, impeller should handle not only water
but water and rigid plastic flakes so, your supplier will start to have a
question mark on his face.
Another very important point of the system is the
size of the inlet pipe; of course the smaller the size the highest the
- Yes, but flakes size should be taken into consideration as well.
top of everything, the smaller the flow, the bigger the residence time (into
vertical cylinder) to allow different materials to separate.
Solution to all this is, of course, a compromise among inlet
size, pressure, flow rate and % of flakes into water.
When you find the right
relation among all those, you're set.
make a long story short, there are a lot very detailed books talking about
hydrocyclones but no one, always as far as we know, clearly defines all
parameters to be taken into consideration when rigid materials, with a pretty
good size, are involved.
If you like to get more information we will be glad to tell you
as much as we know about it and about experience we got with different
materials, sizes and whatever else involved in the process.
did make an example talking about separation between
PET flakes and olefins but, of course, hydrocyclones
can be used to separate different specific weight
plastics of any kind.