Pegging is a form of screen blinding in which particles become wedged point-first in screen openings, standing upright like pegs and reducing the effective open area of the screening surface. It is a mechanical obstruction problem distinct from blinding caused by moisture or static. Pegging is most common when screening elongated, flat, or needle-like particles on woven wire cloth where the particle's minor dimension is close to the aperture size.
When particles peg, they physically occupy the screen opening without passing through, creating a blockage that reduces the available screening area. Over time, accumulated pegging can reduce a screen's effective open area by 30-60%, dramatically lowering throughput and screening efficiency. In round vibratory separators made by Sweco, Kason, Midwestern Industries, and ScreenerKing, pegging is addressed through amplitude adjustment, ball deck systems, or ultrasonic deblinding.
Pegging vs. Other Screen Blinding Problems
| Problem | Particle Shape | How It Lodges | Primary Solution |
|---|---|---|---|
| Pegging | Elongated, flat, fibrous | Wedges point-first from above, stands upright | Ball deck, increased amplitude, slotted mesh |
| Plugging | Near-spherical, near-size | Lodges partway through aperture, stuck in opening | Slightly larger mesh, ultrasonic deblinding |
| Blinding (adhesion) | Sticky, moist, fine | Coats and seals openings from above | Anti-blinding coatings, heated screens |
| Static cling | Very fine, dry powders | Electrostatically attracted to wire surfaces | Grounding, anti-static treatments, humidity control |
Why This Matters in Vibratory Screening
- Throughput loss — Each pegged particle permanently blocks one screen opening until cleared. Cumulative pegging can reduce effective open area by half, requiring more frequent cleaning or larger separator sizes.
- Product quality — Reduced open area forces more near-size particles to travel to the discharge spout as oversize, increasing product loss or contaminating the oversize fraction.
- Screen damage — Aggressive cleaning to remove pegged particles can stretch or tear screen cloth, shortening screen life.
- Prevention strategy — Identifying pegging early allows operators to adjust amplitude, frequency, or screen media type before throughput drops below acceptable levels.
Related Glossary Terms
- Plugging — Near-size particles lodging within screen openings
- Near-Size Particles — Particles close to the aperture size that cause blinding
- Ball Deck / Ball Tray — Bouncing balls that knock pegged particles free
- Ultrasonic Deblinding — High-frequency vibration that prevents particle lodging
- Amplitude — Stroke distance that helps eject pegged particles
- Screen Cloth — The screening surface where pegging occurs
Pegging FAQs
What is pegging on a vibratory screen?
Pegging occurs when elongated, flat, or irregularly shaped particles wedge point-first into screen openings, standing upright like pegs. The wedged particles reduce effective open area, lowering throughput and screening efficiency. Pegging is most common with fibrous, flake-shaped, or needle-like particles on meshes where the particle's minor dimension is close to the aperture size.
How do you prevent pegging on a vibratory screener?
Prevent pegging by increasing amplitude to bounce wedged particles free, using ball deck or ultrasonic deblinding systems, switching to a slotted or rectangular aperture screen, or increasing mesh size slightly. Adjusting the lead angle to change material dwell time can also reduce pegging.
What is the difference between pegging and plugging?
Pegging involves particles wedging point-first into openings from above, standing upright in the aperture. Plugging involves near-size particles lodging completely within the screen opening, stuck partway through. Pegging is more common with elongated or flat particles while plugging affects near-spherical particles very close to the aperture size.
Solve Screen Blinding Problems
ScreenerKing offers ball decks, ultrasonic deblinding kits, and replacement screens in multiple weave patterns to eliminate pegging on any separator.
