PM-STS-DDA
DRAIS Continuous Direct Dispersion Plant
DIRECT PERL MILL

DIRECT PERL MILL, Type PM 40 STS-DDS.

The solids, shown in red, flow through the inner tube of the inlet shaft into the screwfeeder, whereas fluids, shown in yellow, are pumped in from the side through an adjustable annular gap and run down the walls into the feeder screw. This arrangement prevents bridging of solids ahead of the filling aperture.

Applications Micro fine grinding and dispersing solids in liquids without pre-mixing and cell fractionation without preliminary treatment, i.e. in a single operation; for the preparation of, for example, pigments, palletized carbon blacks for carbon and printing inks, titanium dioxide clinker, herbicides, insecticides, ferrites, magnetic tape compounds, sulphur, silicates, semi-conductor compounds, cacao nibs, carbons for fine dispersions, etc.

System advantages
Obviation of pre-mixing or preliminary treatment. Individually batched components or mixtures thereof are fed straight into the grinding chamber. Enclosed system prevents environmental pollution; no objectionable emissions of dust, vapors or fumes. Lower power requirement per unit of production. Materials handled include those difficult to disperse or prone to settling out and in the past could not be processed in agitation mills or only after preliminary preparation. Dissolving and melting can be performed within the work cycle. Frictional gap separator for grinding media retention at product discharge outlet. Optimum temperature control through triplex intensive cooling system.

Grinding Container
Stationary cylindrical pot. Bolted demountable bottom. Pot jacketed for turbulent flow water cooling or heating. Lining of hard steel, alloy steel or mild steel with hard chromium plated finish. Radially disposed activating pins of high manganese steel or sintered hard metal.

Agitator Configuration
Agitator shaft and discs can be heated or cooled. Agitator assembly including discs and pins produced from materials compatible with grinding pot.

Agitator Shaft
Seal Stuffing box, lip seal or pressurized double acting mechanical seal with locking fluid.

Material Infeed
Individually driven special purpose screw feeder, flange-mounted on the end of the grinding pot, with tubular infeed for solids; side mounted inlet stubs for liquids.

Grinding Media
CHROMANITE steel beads or DRAISAL special ceramic beads, 0.8 mm to 5mm in dia., depending on product requirements.

Grinding Media Retention
Frictional gap separator (rotor-stator principle) protected by several patents, specially developed for separation of grinding media from highly viscous charges.

Agitator drive
Built in three phase motor with vee belt transmission; sizes from PM 40 STS-DDA with intermediate starting clutch.