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Although the crushing process is an important part in a crusher plant, the screening quality and precision has the highest influence on the overall efficiency of all equipment. As the heart of every crushing and screening plant, a vibrating screen is used for classifying material by size in every stage of the process from feeding to the product separation. The different sizes of materials mixing with each other and an increase in returning material amount caused by low screening efficiency equals low profitability for every crushing and screening plant.

Screening equipment consists of a drive that induces vibration, a screen media that causes particle separation, and a deck that holds the screen media and the drive and is the mode of transport for the vibration. It is used during the mechanical screening processes, designed to separate one material from another. As the second part of the material handling process, screening equipment is used to separate raw material from a crusher or quarry into even finer grades, coming closer to an end product.

There are a variety of different types of screening equipment, as different materials have different characteristics and requirements for the result. For example, in the construction industry there are a variety of shapes and sizes needed for different jobs, whether it's a new building or road maintenance. To get the maximum amount of efficiency along with the correct particle size, there are several parts of screening equipment that vary to get the needed result. These variables include the screen material, size, slope, hole openings, number of decks and type of vibration motion.

Horizontal Screens

These screens provide outstanding performance for all screening and can be widely applied in mining, aggregates, and concrete and asphalt recycling. The special applications for Horizontal screens include: when fine screening with a large percentage of near size product, wet washing or when low head room is critical such as mobile mounted equipment.

Horizontal screens are named because they are designed to be horizontal. The work direction of the screen is parallel to the ground or has a slope of 0 to 10o. Compared with the inclined screen, it is more accurate and effective to determine the size and separate materials. Rather than relying on gravity, the feed is propelled forward by the linear (or sometimes elliptical) motion of the screen. The feed, thus, stays on the screen for a longer time than it would in an inclined screen of the same size. As a result, material has more opportunities to fall through the apertures, and more effective screening can take place. This makes horizontal screens especially useful for secondary screening and final sizing. Another reason for choosing horizontal screens is the lower installation height. The screen has the advantages of simple structure, reliable performance, large screening capacity, and economical use. Its low power consumption and low maintenance cost, it is the simplest and most practical screening equipment in the crusher plant.

Inclined Screens

This remains the most widely used type of screen, on account of its relative simplicity and low cost. It's made up of a frame inclined at an angle of around 15° to 25° to the horizontal, to which the screening media is attached. A rotating unbalance mechanism drives the screen body in a circular motion which, combined with gravity, moves the feed material towards the discharge end. An inclined screen can have multiple decks, allowing for separation into several grades.

Inclined screens are fairly versatile, and suitable for a range of different applications. As well as changing screen media, it's often possible to adjust the inclination angle, stroke length, and rotation speed according to the user's goals. With this versatility, an inclined screen is suitable for almost any type of screening.

Grizzly Screens

Very coarse materials are usually screened using an inclined screen called a grizzly screen. Grizzlies are characterized by parallel steel bars or rails set at a fixed distance apart and installed in line with the flow of the material. The gap between the grizzly bars is usually greater than 50 mm, and can be as large as 300 mm, with a feed size of up to 1 m. Vibrating grizzlies are usually inclined at an angle of around 20° and have a circular or linear throw mechanism.

The bars are typically made from wear-resistant manganese steel and are usually tapered to create gaps that become wider towards the discharge end of the screen to prevent material from wedging between the bars. These screens are for the most rugged and heavy-duty scenarios. Grizzly screens are generally used as a feeder prior to the crusher to supply the flow of correct-sized material through the crusher.

Banana Screens

The banana screen is designed by injecting a banana-shaped multi-stage working surface based on a linear classifier. There is a larger slope screen at the feed end, followed by a stepwise decrease at a certain number of angles until the discharge opening, the overall screen surface is concave curved. The sloped screen at the feed end allows for more material to pass through the screen surface with higher screening speeds and thinner material delamination. Modern banana screening machines achieve good separating accuracy at an extremely high feed rate and with difficult-to-screen material. Its operational behaviour makes it a high-speed screen. Compared with conventional vibrating screens, the banana screen handles a considerably larger feed quantity for the same screen area. Different gear unit sizes enable outstanding setting-up to suit the specific application. Balance masses and speeds can be adjusted in stages, enabling linear vibration amplitude and screen box acceleration to be optimally adapted to meet process requirements.

High Frequency Screens

High-frequency screens are engineered to provide higher production capacities and more efficient sizing than conventional screens. High-frequency screens operate with aggressive vibration applied directly to the screen, which allows for the highest capacity in the market for the removal of fine material, as well as chip sizing, dry-manufactured sand and more.

The high-frequency and low-amplitude operation ensure a faster material travel speed without loss of screening efficiency. This combination of high frequency and low amplitude is ideal for fine material screening, in which coarse material particles are lifted higher while the finer particles stay closer to screen, and as a result, the probability of separation is increased with high-frequency screens.