Fine screens are used for the mechanical pre-treatment in waste water treatment plants. The major task of fine screens is reliable removing of inorganic solid materials. With our 30 years of experience in water treatment and our knowing about weaknesses of other fine screening technologies we have developed our fine screen CONE STAR that maximizes strengths for our clients benefit.

The CONE STAR is working according to the counter flow principle. Bigger solids than the spacing are hold back by the screen basket and organic materials are washed out by the passing wastewater. To ensure a reliable cleaning of the screening area the screen basket is automatically cleaned by a special cleaning cycle. The cleaning cycle works without any moving parts like rake cleaner! The CONE STAR is usually installed in the rectangular channels with an inclination of 30° against horizontal.  

Screening:  
The CONE STAR works with a screen basket that is driven in combination with the screw conveyor by the same engine.  The rotation (see Fig. 02) of the basket ensures the reliable wash out of organic materials and the cleaning of the screening surface by the fixed washing device. The cleaning cycle works without wear intensive mechanical parts like rake cleaner or wiper.

Cleaning cycle:  
If the water level rises to a preset level, the cleaning cycle will get activated! The screen basket will rotate 720° in the wastewater to wash out organic content from the screenings. Inside the screen basket 3 radial blades are mounted that lift up floating screenings by the rotation of the screen basket! After completing the second rotation the magnetic valve of the back washing device opens. Water with pressure between 2,5 and 4 bars cleans the screen by using an increase of the velocity between the wedges. The screenings are washed out of organics again and fall down into the opening of the screw conveyor by impulse of the water and gravity.  

Dewatering and pressing:  
To minimize the quantity for easy handling and expenses for disposal in further progress the screenings should mostly be dry. Therefore the CONE STAR is equipped with a dewatering and pressing device. The screw conveyor can discharge either to a belt conveyor, a container or an optional bagging device.

Emergency overflow:  
In case of a power blackout an optional overflow-coarse-screen provides a mechanical pre-treatment until the breakdown is eliminated.

Overload protection:
To protect CONE STAR components against damage, the gear motor is controlled and switched off by overload control. This overload control works with electrical or mechanical devices.


Service/Maintenance:
Most of the CONE STAR components are made of 1.4301/AISI 304 or 1.4571/AISI 316. The bearings of the screw conveyor are reliable sealed against waste water.

The special design of the CONE STAR enables to swing it out of the tank into maintenance position. The maintenance staff doesn’t need to move down in the channel to make inspection or service at the screen it selves. So a high quality of service is ensured because the maintenance is able to work in upright position.  


Installation:  
The CONE STAR will be delivered ready for operation, completely installed & tested. At the site the CONE STAR has to be installed into the channel.


Sizing:
The CONE STAR is designed for channels bigger than 1000 mm. The spacing of the mesh is available in various sizes. The length of the screw conveyor is depending on the depth of the cannel and the discharge height.

Options:  
  strengths are individuality and flexibility. We are able to adapt our equipment in a line with client’s requirement.

For outdoor installations we optionally provide also a heating system.  


Benefits:

Ø       High reduction of organic content in the screenings because of multi-stage wash process

Ø       Effective cleaning cycle ensures free screening surface without rake cleaner or wiper => no abrasion

Ø       Less stress on the other components (shaft) through less weight of the screen basket => optimized screening surface

Ø       Efficient dewatering and pressing of screenings

Ø       Easy to maintain because of maintenance position

Ø       Spare part availability all over the world

Ø       High operation safety because of minimum moving parts

Ø       Flexibility

Ø       ……