Inclined vibrating screens are a crucial component in the cement industry, used primarily for the separation and classification of materials. Their working principle is based on the use of gravity and vibration to achieve efficient particle separation. Here is a detailed explanation of their working principle:
1. Structure and Design: Inclined vibrating screens are designed with an inclined frame, typically set at an angle between 15° and 30°. This inclination allows gravitational acceleration to assist in the movement of materials across the screen surface. The screen body vibrates circularly due to helical springs, which are integral to its design.
The screen consists of several key components:
Side Walls: Provide structural support.
Decks: Hold the screening media.
Screening Media: The surface through which particles are separated.
Exciter: Generates vibrations.
Electric Motor and Motor Console: Powers the exciter.
Spring and Spring Supports: Absorb vibrations and provide stability.
2. Vibration Mechanism: The vibration mechanism is central to the operation of inclined screens. An external electric motor drives this mechanism via a belt and pulley system, creating a circular motion that propagates throughout the screen body. This motion is facilitated by eccentric masses attached to the exciter, which can be adjusted to change the stroke length (typically between 8 mm and 12 mm).
3. Material Flow: As materials are fed onto the screen, they encounter an impact area that breaks up larger particles, ensuring they lie flat for effective screening. The combination of gravitational force from the incline and vibrational energy causes materials to move across the screen surface.
Particles smaller than the mesh size fall through the screening media, while larger particles continue along the deck until they reach an outlet where they are discharged. This process effectively separates materials into different size fractions.
4. Multi-deck Configuration: Inclined screens often feature multiple decks, allowing for simultaneous classification into several grades or sizes. Each deck can have different mesh sizes tailored to specific requirements in cement production processes.
5. Advantages: The simplicity of their design makes inclined vibrating screens cost-effective with low maintenance needs. Their bolt-and-nut assembly prevents issues associated with welding, such as cracking or failure under stress.
In summary, inclined vibrating screens utilize a combination of gravitational forces and mechanical vibrations to efficiently separate particles by size during various stages of cement production, from raw material processing to finished product classification.
