Retsch AS 200 User Manual download pdf (Page 26)

31.07.2012  Retsch GmbH 26

Wet sieving

Dry sieving will be possible in the large majority of

cases. There are, however, some materials in which the

adhesive forces between the individual particles can

cause difficulties. These problems can be eliminated by

adding liquid, preferably water, during the sieving

operation (in so far as the additives mentioned in the

chapter on “sieving aids” were not successful). One

pre-condition for wet sieving, however, is that the sub-

stances to be separated will not swell, dissolve or other-

wise interact with the liquid.

Required accessories

* Clamping cover with spray nozzle, matching the sieve

diameter.

* Base pan with water drain, matching the sieve

diameter.

Preparations

* Position your AS200 near a water drain.

* Use a hose to connect the spray nozzle in the

clamping cover to a water faucet.

* Connect the drain from the base pan with the drain or

a suitable container to receive the liquid.

Operation

* Apply the solid in the form of a suspension.

* Set the liquid (water) supply rate so that the spray just

covers the sieve surface completely.

* Using dispersion agents is advisable. They reduce the

surface tension of the sieve liquids.

* When dealing with goods which resist forming a slurry

or where more exact separation is required, spray

each individual fraction, one after the other.

* Following the sieving process, the fractions are to be

transferred from the individual sieves to suitable filters

(e.g. filter paper) and dried in a drying cabinet at 80°C.

* Then clean the sieves in an ultrasonic bath and dry

them, too, in the drying cabinet (without the gaskets).

Do not exceed a maximum drying temperature of

80°C.

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Retsch AS 200 User Manual Page 26