A vibrating screen is often seen as the efficiency tipping point for an entire mineral processing operation.
After all, it’s where multiple processes finally come together, and the final aggregate product is sorted. While the vibrating screen tends to receive all the glory, the internal screen media is often an overlooked workhorse.
Screen media must be trusted to perform efficiently and accurately. For this to happen, contractors and producers must choose screen media that is a perfect fit for their specific operation to work at peak performance.
This ideal fit can be found by evaluating any current screening challenges, looking at the application’s needs and comparing the advantages and disadvantages of some of the most popular categories, including synthetic and rubber screens, heavy-duty rubber and perforated steel screens, as well as standard and high-vibration wire screens.
Synthetic media
Synthetic media, such as rubber and polyurethane, are known for their ability to reduce noise levels and for their long wear life.
This type of media typically has less open area than wire screens, leading to decreased throughput and reduced bottom-deck capacity since the material takes longer to make its way down. Operations using synthetics must keep a close eye on the openings in the panel, as they tend to wear by rounding out, making it necessary to regularly check that out-of-spec material isn’t getting through.
Synthetic screen media also tends to be very rigid and relies on the vibrating screen to do most of the heavy lifting. The static movement of the screen limits vibration to 800 or 900 cycles per minute. In most cases, this does not hinder the screen media from achieving adequate production and throughput, but it also doesn’t take full advantage of the screening equipment.
Synthetic media can also be more susceptible to common issues, such as blinding and pegging.
Heavy-duty media
Steel plates and heavy-duty rubber are the most durable options.
Perforated steel plates are a good option for applications requiring a durable screen media, but they are extremely heavy, which can make maintenance and operation more cumbersome. Additionally, their open area is often quite low.
Rubber is quieter and can be effective for screening material with a large top size, but it tends to be more susceptible to pegging.
Consider the drop height, material size, abrasiveness, weight and volume. Naturally, the more impact the material will have on the screen media, the higher the durability the media should have, at least at the point of impact. Additionally, abrasive materials – such as granite – require resistant screen media.
However, the rigid construction of steel and rubber makes for limited throughput, which must be considered alongside durability to achieve peak efficiency.
Wire screen media
Woven wire cloth has been the traditional option for a reason. It is relatively inexpensive and effective.
However, limited wear life and frequent changeouts lead many operations to consider more advanced options.
High-vibration wire screens offer a wear life compromise between synthetic media and woven wire, often providing the most performance benefits. Some high-vibration wire screens feature high-strength wire bonded by polyurethane strips to maintain individual wires in parallel alignment. The wires vibrate independently within specified opening sizes to amplify the screening process and increase throughput by up to 40 percent.
Additionally, the vibrations prevent or significantly reduce pegging, blinding and clogging issues, improving product quality and reducing potential downtime.
Some manufacturers can customize screen media to a specific application. When properly fitted, high-vibration screen media can amplify the work of the vibrating screen with vibrations of 6,000 to 10,000 cycles per minute – up to 13 times greater than traditional, rigid media options.
Often, the screen media can be modified with thicker or double wires and additional polyurethane to further boost durability.
Making the right choice
Screen media is ultimately the mechanism that keeps saleable rock from being sent to the crusher, and maximizing its efficiency shouldn’t come at the expense of higher maintenance.
Some manufacturers promising quieter or cheaper screen media have forced customers to compromise on the ultimate goal of performance and efficiency. High-vibration wire screens offer a solution – not another compromise.
Serge Raymond is a product specialist at Major.