Technology

What tasks are KROOSH screens designed for?

KROOSH screeners provide solutions for a wide range of industrial processes, primarily the ability to efficiently screen hard-to-screen products such as wet and sticky bulk materials, as well as suspensions and polydisperse slurries with particle sizes from 15 microns to 30 mm.

What is the difference between KROOSH screeners and other screeners of other brands?

It’s well-known that screens are different, and, among other things, it is possible to distinguish such types as:

• Vibrating screens
• Oscillating screens
• Drum screens, etc.

KROOSH screens are related to vibrating screens, but, at the same time, they are fundamentally different from them. Usually, when talking about vibrating screens we mean a standard single frequency vibrating machine. KROOSH screeners are multi-frequency vibrating screeners.

The main idea of operation of a conventional vibrating screen is that the vibration motor excites the screen mesh transmitting vibrations either to the screen body or directly to the mesh.

Screen vibration energy is important for screening performance:

• mesh acceleration prevents mesh clogging
• acceleration of the screen mesh allows breaking the adhesion of particles to each other
• in case of slurries the acceleration of the screen mesh allows breaking the surface tension of the liquid.

The acceleration of the screen mesh of a single-frequency screener is very small and is more or less equal to the acceleration of the screener body i.e. a conventional (single-frequency) vibrating screener the amplitude of the body and the amplitude of the screen mesh are equal to each other and they are approximately 4-5 mm. This not only leads to clogging of the screens, but also - compared to multi-frequency screens - reduces the specific productivity of the equipment.

The main idea of KROOSH screeners is that single-frequency oscillations of the motor or screener’s body are converted into multi-frequency oscillations of the screen mesh with the help of a special mechanical device.

What are the advantages of multi-frequency technology by KROOSH?

• Fast particle separation: due to multi-frequency oscillations, the bulk medium is effectively loosened, mixed and segregated, ensuring the rapid penetration of fine particles to the mesh surface.
• High relative productivity and high efficiency: since fine particles reach the screen faster, this provides the most efficient screening mode along with high throughput, and as a result, significant savings in energy costs per kg / ton of product.
• Room saving: due to the high relative productivity, the screening area is significantly reduced compared to conventional screens.
• Self-cleaning screens: multi-frequency oscillations of the screen create such accelerations that provide continuous self-cleaning of the screen during the screen’s operation.

Please, have a look at how the same products are screened by a conventional vibrating screener and by a KROOSH multi-frequency screener.

How does the KROOSH technology work?

KROOSH technology is based on the principle of influencing on a granular medium feeding in a screener with a continuous frequency spectrum corresponding to the frequency spectrum of this particular granular body.

As a result, the granular material gets the properties of a liquid. Outwardly, it looks like the movement of a turbulent fluidized layer of bulk material along the mesh. In this state, the segregation phenomenon is sharply activated in the layer, and small particles in a very short time pass through the layer to the screen mesh and then through the mesh apertures.

We developed the special mathematical model which adjust the following screen parameters:

1. Frequency spectrum of screen oscillations:

Frequency spectrum is responsible for the self-cleaning of the screen mesh, for interacting with the material on the screen mesh and for its rapid mixing in order to quickly separate the layers.

• Conventional vibrating screener oscillates only at one frequency, albeit high, but only at one.
• The multi-frequency screener has a continuous spectrum of frequencies: the acceleration of the screen mesh reaches 50-100g and even 200g if needed, and on a conventional screen it’s only 3-4g.  Depending on the product we screen – how fragile is this? what is the bulk density? what is the abrasiveness? etc. – we set up the screener’s acceleration accordingly.

2. Screen mesh stroke

Screen vibration energy is important for screen performance. The combination of a wide frequency spectrum and a large amplitude of screen mesh vibrations provide energy transfer to the material layer, which is much higher than the energy on conventional screens. This allows you to get a significant increase in the performance of a multi-frequency screener comparing to conventional screeners.

• In a conventional vibrating screen, the stroke of the body and the stroke of the screen mesh are equal to each other and are equal to approximately 4-5mm.
• In a multi-frequency screener the stroke of the body itself can be even smaller (for example, 1-2mm), but inside the screener there is a second mass (Kroosher system), which converts the vibrations of the body into vibrations of the screen mesh, and the stroke of this second mass is 2-3 times higher than the amplitude body (for example, 6-7mm), and the transmitted amplitude from the Kroosher system to the screen mesh is even higher (for example, 10-15mm).

Thus, the developments of our team of scientists have made it possible to create a unique type of equipment for screening & sizing of hard-to-screen products with high quality and efficiency.