MANTIS Conveyor Products

CEMA Idler Test Report
MANTIS Conveyor Products® — Put to the Test

What We Tested:

MANTIS Conveyor Products® CEMA Idler

Why We Tested:

Bearing contamination can cause idlers to spin roughly or seize. That leads to downtime – and time is money. To shield bearings from contaminants that can affect performance and ROI, we designed MANTIS CEMA-rated idlers with four layers of protection:
  1. External Nylon Labyrinth Seal
  2. Secondary Internal Labyrinth Seal
  3. Chamber Lock Technology
  4. Proprietary Defender® Bearings

How We Tested:

Our CEMA Idler Slurry Tester simulated loading per CEMA Standard 502 at a belt speed of 400 FPM for the NHI MANTIS CEMA idler and two leading competitors. Instead of just water spray, we ran multiple tests using a slurry consisting of chemicals and particles designed to corrode, penetrate, and abrade the test article.

What We Found:

After 40 hours of slurry testing, we manually disassembled all three idlers.

Competitor #1 Idler:
  • Completely seized.
  • Excessive contamination in both bearings throughout the inner cavity.
Competitor #2 Idler:
  • Idler spun very rough.
  • Heavy contamination in one bearing with evidence of slurry pass-through.
  • Second bearing also showed signs of contamination.


  • No degradation in external labyrinth seal.
  • Internal labyrinth seal maintained full contact with bearing housing.
  • Slurry fully contained within chamber lock.
  • No debris on bearing seals.
  • No contamination inboard of bearings.
  • ZERO contaminates found in bearing grease!


MANTIS CEMA Idlers stand up to the toughest conditions and keep your line moving.