Three screening 101 takeaways

Screening is a fundamental component of every operation. Photo courtesy of Polydeck

Joe Schlabach, vice president of marketing and sales at Deister Machine Co., led a presentation on the basics of screening at the 2019 AGG1 Aggregates Academy & Expo in Indianapolis.

The presentation targeted novice plant design personnel, covering basic concepts needed to understand critical screening operations.

Here are three takeaways from Schlabach’s presentation:

1. Screening is a combination of art of science. Simply put, screening is the process of agitating material, causing that material to stratify and allowing smaller material to fall through openings in the screening surface.

According to Schlabach, this process, although relatively simple, involves a combination of creativity and data to create an effective screening plant. Screening parameters should be specially designed for the type of material and screen box. These parameters include the speed and stroke of vibration on the box, the direction of the vibration rotation, and the incline angle.

2. The basics of dewatering screens. The sole purpose of a dewatering screen is to remove water but retain all material, Schlabach explains. Commonly used in an ultra-fines recovery application, a dewatering screen should be as efficient as possible so material isn’t lost through media openings.

3. Key terms. Schalabach detailed several terms every screen operator should be aware of, including:

• Plugging. Sized material plugging the opening on the screen.
• Blinding. Fine particles sticking to the surface of the screen media due to moisture gradually blazing over openings.
• Carryover/dirty material. Excessive undersize particles failing to pass through the screen.