Classification, the division of granular material into various size groups, is one of the most important steps in the production process. Screening in the broader sense also encompasses thickening, pre-screening, control screening, dewatering and deslurrying. The screening result depends on the correct assessment of the material to be screened, the choice of mesh and the execution and adjustment of the screening machine.

The success of screening is determined by the quality of the product obtained, i.e. the proportion of undersized/oversized particles in the various grades.

It is evident that best result cannot be achieved cost effectively, with just one type of screening for all applications. The requirements are too demanding and materials too numerous.

It is therefore advisable to refer your problem to a specialised screening machine manufacturer who not only has an extensive range of machines in his delivery programme but has qualified staff with experience in your particular field.

Table 1 explains the technical differences between circular and linear motion screening machines – the main groups in the range of modern screening machine manufacturers

Types of machine Circular motion screening machine Double counter
weight screening
effective screening width mm 400-2400 600-5500
effective screening length mm 800-6000 1900-11000
screening area m2 0, 3-14, 4 1, 2-50
motion Circular Linear
amplitude mm 2- 6 3- 8
speed min-1 800-3000 700-1000
angle of throw degree 75-85 35-60
screening angle, normal degree 10-22 0-12
screening angle, special execution degree 8-40 Upto 40
transport speed, normal m/s 0, 12-0, 3 0, 2-4, 4
transport speed, special execution m/s Upto 4, 0 Upto 4, 0

Modern Screens

modern_screensModern screening plants are judged by the quality of material produced, throughput for a given screening area, availability, power consumption and personnel required, in other words, the overall economy.

There is an ever increasing demand for higher throughputs,calls for larger machines, not least because they are more economical. Having recognised this trend, we developed and manufactured “large screening machines”, for preparation plants with high capacities.

At the same time, our wide range of screening machines for small and medium capacities are also being developed using latest technology. We build and supply specialised screening machines for pre-screening, underwater screening and sand-screening. They can be mobile, stationary with dust covers, or for classifying.

Types of machine Material Characteristics Circular motion screeningmachine Double counterweight
screening machine
Classification Coarse, dry
Classification Coarse, moist
Classification Coarse with sprays
Classification Fine, dry
Classification Fine, moist
Classification Fine with sprays
Enrichment Coarse
Enrichment Fine
Pre-Screening Coarse
Pre-Screening Coarse
Control Screening Fine
Dust Removal
Deslurrying O
De-Pulping O
Thickening O
When compiling this table, both commercial and technical aspects were considered.Legend 

• recommended

☐ recommended with reservation

O not recommended


Circular Motion Screens


  • Sand and gravel, building materials
  • Rocks, crushed stone, chippings
  • Minerals, ores, pellets, sinter
  • Coal, coke, petrol coke
  • Chemical products, fertilisers, granular material
  • Salts, sugar
  • Compost, refuse, refuse slags

Operational Characteristics

Circular motion screens are freely vibrating. This means that the amplitude is self regulating depending on the relationship between the weight of the screen itself and the counterweight. Circular motion machines have a steep angle of throw and therefore require an inclination of 10º- 22º.


Exceptions are the dewatering screen at 3º-5º and steep screens, for example when screening sand at an angle 20º- 40º.

Machine Details

The screen frame, consisting of side plates and cross-members,absorbs all static and dynamic forces. The drive shaft with eccentrics runs in 2 roller bearings that are positioned at the centre of gravity. Drive is either via V-belts or flexible coupling. Lubrication of the bearings is either by oil or grease. The screen frame with 4 sets of springs rests on the support construction and can be manufactured to accept lengthwise or crosswise tensioned sieves as well as flat panels. For dusty materials we supply the machines with either a dust hood or a complete dust enclosure.

Technical data for Circular motion screens
Effective width mm from 400 upto 2400
Effective length mm from 800 upto 6000
Inclination degree from 8 upto 40
Speed min1 from 800 upto 3000
Amplitude mm from 2 upto 12
Angle of throw degree from 75 upto 85
We reserve the right to make changes that serve technical progress.


Double Counterweight Screens


Coal, raw and washed

Ores, minerals, granular material

Rocks, limestone

Coal, coke, petrol coke

Sand and kies, baustoffe

Operational Characteristics

“Banana” screens are high speed screening machines. Due to the steep screen inclination, high transport speeds are achieved. A very thin layer is formed and a large proportion of the fines pass through the elongated apertures. The inclination is less in the middle and discharge section, which reduces the transport speed. In these sections a good separation, even of marginal particles, is achieved.

Technical data
Effective width mm from 800 upto 5500
Effective length mm from 1900 upto 5500
Effective length degree from 800 upto 40
Speed mm-1 from 700 upto 1000
Amplitude mm from 6 upto 16
Angle of throw degree from 35 upto 60
We reserve the right to make changes which serve technical progress


For more than five decades, we have maintained leadership with proven technology, consistent quality, committed delivery and effective customer service in the field of crushing screening, material handling, grinding, beneficiation and pyroprocessing.


As pioneers in the turnkey execution of mining and processing plants, viz coal, iron ore, steel, aluminium, cement, fertilizers, power generation and minerals, we harnessed a dedicated team of professionals and built a fully equipped workshop to provide innovative technology and cost-economical equipment for all


A growing list of satisfied customers is a testimony to this.