5 Questions About the Evolution of GK’s FINGER-SCREEN™

Custom Content - Ask the experts | Screening Technology

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July 12, 2019

1. When were the first screens created?

Back in the late 1960s, General Kinematics (GK) designed and engineered a dual knife DE-STONER® Air Classifier for use in the wood industry. The DE-STONER® Air Classifier combines vibration, fluidization, and an air knife to separate materials by density. To optimize the separation, we realized the need to control the size of the particles presented to the air knife. Initially, GK’s engineers incorporated a traditional perforated screen deck for this application but quickly discovered the limitations of this setup.

In a traditional perforated screen deck, the perforated hole is made perpendicular to the deck. As a result, material that is slightly larger than the opening gets trapped within the hole, plugging up the screen deck and making screening ineffective. We needed a better way to screen.

2. How Did Screens Evolve?

Dick Reeves, General Kinematics Director - Resource Recovery

While the original perforated plate is appropriate for other industries with similar shaped materials, it is inadequate for the wide variety of shapes and sizes typically found in the recycling industry. Larger and odd shaped materials are more challenging and require a different approach to screening.

We made a slight change to the traditional perpendicular perforated screen by angling the axis of the hole away from vertical. The result creates an incline ramp that helps material climb out of the hole and decreases the plugging of the deck. Even though this evolution was an improvement, the fundamental issue of material getting trapped in a four-sided hole remained.

3. Can You Fit A Square Peg In A Round Hole?

Common sense says no, you cannot. This analogy is especially true when screening recycling materials. In a round opening, you create a four-sided constraint that traps oddly shaped particles. So, while an inclined ramp did help move some materials climb out of the hole, it still wasn’t sufficient enough for much of the product.

4. What If A Screen Had a Three-Sided Opening?

Imagine how a three-sided opening would look. Then flare out two sides to create a tapered, three-sided opening. Also, now include that inclined ramp we developed earlier. We’ve just created GK’s FINGER-SCREEN™!

The FINGER-SCREEN™ is inherently self-relieving, and the inclined ramp creates a three-dimensional material with more uniformed product distribution. The round hole problem was solved, and the screens now could be used for a variety of applications.

5. What Have You Done Lately?

Let me introduce you to GK’s latest innovation in screening. Our FINGER-SCREEN™ 2.0 Primary Screen takes screening to the next level. Featuring all the benefits of the original FINGER-SCREEN™, this new design provides a longer displacement that moves traditionally difficult to screen materials. When used as the primary screen, FINGER-SCREEN™ 2.0 provides the initial size separation which scalps off any potentially destructive contaminants, allowing the rest of the downstream equipment to operate effectively.