For Removal of flat, narrow and long foreign matters (Heavies) and also light weight contaminants such as corks, plastic pieces. This is most suitable for primary Screening after the pulpers. The table given below the relation between stock consistency and Screen perforation for selection.

Consistency (%)	Hole Perforation (mm)	Slot Perforation (mm)
3	5 - 3	1.5 - 10
2.5	3 - 2.5	1.0 - 0.7
2	2.5 - 2.0	07. - 0.4
1.5	2 - 1.5	0.4 - 0.3
0.5	1.2	1.15 - 0.1

Middle Body:
Middle body consist one no. stock inlet for tangential feeding the stock which is being accelerated by rotating impeller.

Bearing body:
Bearing body and rotor with perforated extraction plate is fitted in the upper body.

Bed Bar:
Bed bar in addition to breaking the stock the bed bar acts upon the change of flow from rectified to turbulent, to minimise the flake contents.

Accept Stock outlet:
The stock entering under high pressure is exposed to impact and shear forces caused by the impeller / bed bar for defibration and goes upward through perforated extraction plate while foreign matters down into the tail cyclone for removal.

High Pressure back water Pump:
It takes water from thickner tank and clarified water is fed to tail cyclone making pulp consistency low and also in main unit to increase turbulence.

Setting tank / Junk removal tank:
The heavies rejected in tail cyclone settle in the jun tank for intermittent manual removal .

Floating stock outlet:
The stock flowing in the setting tank together with the heavies goes upwards to get thruogh the floating stock outlet at the top of tank and enters the circulation pipe linked to the control part of the mai unit.