Through recent site visits, Brentwood’s Polychem Solutions Team has observed several chain and flight clarifier systems with excessively worn collector chain due to long-term exposure to heavy grit concentrations. Clarifier chain wear can be extreme in high grit conditions such as: combined sewer plants, plants without an effective grit removal system, or coastal facilities with a high presence of sand or snails. Although it is common for a well-maintained longitudinal collector to have 15 to 20 years of chain life, some are showing severe wear in less than 10 years operation, and in certain cross collectors, as rapidly as 3 years.

Evidence of premature wear can be seen in barrel striations and can be measured with a pair of calipers. Polychem NCS-720-S collector chain should be replaced when the barrel OD reaches approximately 1.25″, understanding that striations can make accurate measurements challenging. Polychem Solutions can assist with chain inspection, testing, and may recommend chain upgrades such as GritShield for both drive and collector chains. Uneven wear may indicate flight misalignment or improper chain catenary. If the initial installation date is known and the system has operated continuously, the estimated remaining chain life can be calculated to assist in maintenance planning and budgeting.

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