Tips and Tricks for an optimal use of your mobile screening plant
The quality of the screen lining are very important for sieving results
With the use of a screening plant, the crushing and screening process of natural stone and recycling applications can be made more efficiently. In order to achieve a high-quality end product, the screening plant must be individually adapted to the application. But a few factors need to be considered.
Especially in multi-stage crushing and sieving processes, screening plants are indispensable for obtaining exact fractions.These are later used as standardized aggregates in asphalt or concrete production. A screening plant can also be used alone if, for example, a classified grain size of old asphalt needs to be added to the new asphalt. Compared to stationary technology, mobile solutions therefore score with flexibility and high performance values.
In addition, the systems are installed directly next to the bulk material, so material handling can be reduced. Depending on whether a double-deck or triple-deck screening plant is used, three or respectively four fractions are produced. In order to achieve a high throughput capacity with as little wear as possible, the screen lining, the screen inclination and the layer cover must be selected correctly.
Tips for an efficient operation of the screening plant:
– Selection of screen linings suitable for the application
– Screen inclination: The steeper the screen inclination, the larger the sieve machine must be, as the material falls faster and rests on the sieve deck for a shorter time. If the material is to be sieved very thoroughly, a lower screen inclination is advisable. Although the throughput is lower, the result is more precise.
– Layer thickness: The speed of the infeed belt influences the layer thickness. If the speed is too high, the layer thickness on the screen deck increases. Since coarse material is then bloated, the screening is less precise and also too fine material can intermix with the oversized particles.
Important for a high throughput and a precisely classified end product is a well-organized material flow. Kleemann has generously dimensioned the feed hopper of its MOBISCREEN EVO screening plants so that feeding by wheel loader or upstream crushing plant is possible. The material is transported on the extra wide feed belt of 1,200 mm to the sieve box. In order to adapt the screening plant flexibly to different applications, the screening angle can be adjusted according to the requirements. This achieves high quality and high performance. At the discharge of the feed belt, an impact plate distributes the material evenly on the screen lining.
Factors for choosing the right screen lining
– The material type: natural stone or recycling
– The grain shape: cubic or elongated
– The desired final grain size: Determination of the screen mesh sizes of the sieve decks
– The moisture content: if the feed material is moist, it is important to avoid caking.
– The sieve inclination: The steeper the sieve inclination, the larger the sieve opening must be selected in relation to the desired separation cut.
– Upper deck to lower deck ratio: this must not be larger than 4:1, otherwise the classification is not thorough enough and the application gets less efficient. In addition, the wear increases.
The quality of screen linings is crucial for the screening result. The higher the quality of the covering, the more accurate the cut. Kleemann therefore relies on screen linings that meet high demands for robustness and precision. For the screening of different fractions and materials it is important to be able to fall back on a wide range of screen linings. The most important differences lie in the mesh shape – square, rectangular or harp – as well as in the composition – steel or plastic.
This must be taken into account when screening fine material
If the mesh size of the lower deck is too fine, the covering may close because the fine material sticks. The finer the wire thickness, the less caking occurs and the higher the throughput. But the wear is higher. With thicker wire thickness, the opposite is the case: more caking and less throughput. The screen covering is then more robust. Plastic screen coverings are very well suited for fine material and moist material, as the linings vibrate more strongly and caking is thus avoided. However, the separation cut of these linings is not as sharp as with steel screen covering. In individual cases it also makes sense to choose a coarser upper deck so that the lower deck is knocked free of the coarse material.
In plants that often process thousands of tons of rock during each working shift, maintenance is of particular importance. The large engine compartment of the MOBISCREEN EVO screens simplifies inspection. Further service components are quickly accessible via the revolving working platform with railings. Good access to the screen decks also makes screen lining changes more convenient for the user. For example, the fine grain belt can be lowered to allow access to the lower screen lining. The quick screen lining change and the intuitive operability of the MS EVO make it easy to adapt flexibly to new applications.