Complete Dewatering System

The centrifuge cannot be as a de-watering device until it is installed with the necessary ancillary equipment. This is usually as follows: -

1)      Control panel – usually a wardrobe type panel approx. 1200 mm x 800 mm.

This provides all the contactors and overloads necessary for all the drives associated with the centrifuge system.

It also houses the PLC, which starts these drives in sequence and controls them in accordance with signals-from the control instrumentation.

2)      Centrifuge feed pump – usually a progressive cavity type pump as this provides an almost constant, non-surging flow.

This type of feed pump is normally protected from running in a dry condition in some way.

3)      Sludge macerator – An 0ptional extra sometimes requested by a client if the site is prone to blockages caused by rags or leaves etc. Not essential but can assist more consistent operation.

4)      Polymer makes up system – An essential item polymer is to be used. There are a variety of systems readily available on the market at varying prices. Allied colloids are one such supplier.

Before installing mixing equipment it should be decided by the client whether powder grades or liquid grade products are to be used. The liquid make up systems are far cheaper but liquid grade polymers tend to be more costly to use.

5)      Polymer dosing pump – As with the feed pump a progressive cavity type pump is normally used with this duty.

6)      Cake handling – this can be performed in a number of ways: 

Support entire centrifuge directly above a skip.

Belt conveyor, probably most common and safest method to handle centrifuge cake.

Screw conveyor, very good in the right application, advantage is that the unit is totally enclosed but some cakes can be sticky and do not convey well, e.g. ferric sludge from water treatment works.