Inclined screens operating principle
The micro-launch system was discovered at the beginning of the twentieth century and was immediately used in the screening process for the industrial screens. At first it seemed plausible that the rotary movement induced to the machine was the most effective screening method since it induces a flight trajectory with very steep relapse angle to the particles, increasing their possibility to impact the selection surface, centring the net opening.
The disadvantage of being able to process reduced flows with this system, is compensated by slightly inclining the vibrating screen. This is how the inclined vibrating screens appeared.
Designed with a central transmission shaft and lateral oscillators or using a single electric vibrator, the inclined vibrating screen is a heavy-duty, easy to maintain application.
The rotary inclined vibrating screens are used:
- When there are no limitations in height and size
- When you can accept as net opening the projection of the selection plan nominal opening on the horizontal surface
- When you want to reduce as much as possible the closure of the selection surface net openings when processing particles of critical size. By critical particle size we refer to particles with sizes slightly bigger than the nominal net opening that get stuck in the net if the inclined vibrating screens do not have enough power.
The shape of the elementary particle is very important in cleaning the selection surface; it can be classified in:
- Polyhedral shapes: easily to process
- Prismatic shapes: tend to get stuck in the net
Classification of the inclined screens
The inclined screens are used in multiple applications for various types of products. Vibroprocess continuously enriches its range of rotary inclined vibrating screens, searching for new, innovative solutions for each of its projects
In the screening process with rotary inclined screens, the movement is induced through rotary oscillators that generate a rotary, or better ellipsoidal trajectory as the gravity force, the different response of the springs in various directions and especially the position of the oscillator axis with respect to the center of gravity of the oscillating system, deform the circular trajectory induced by the centrifugal force generated by the oscillator.
The rotary oscillator is poorly efficient in horizontally moving the product along the machine; therefore, the machines provided with rotary oscillators should be inclined to facilitate the movement of the product. There are extremely effective in freeing the particles of critical size from the selection surface of the inclined screens.
For lighter and less complex machines, the ellipsoidal trajectory can be induced by installing a single electric vibrator. The electric vibrator should be placed above the centre of gravity of the screening surface.