Magnet grids (also called inline magnets or magnetic separators) are arrays of permanent magnets positioned within a material flow path — typically in a gravity chute, on a conveyor, or within a pipe — to remove ferrous metal contamination such as nuts, bolts, wire fragments or worn metal parts from ingredients or finished feed before they can damage downstream processing equipment or pose a safety risk in the finished product.

Magnet grids are commonly installed at multiple points in a feed mill, including at ingredient receiving, ahead of grinding equipment where metal contamination could damage hammers or screens, and sometimes at finished product discharge as a final safeguard before bagging or bulk loadout.

Grid configuration typically consists of multiple magnetic bars or tubes arranged in a staggered pattern across the flow path, designed so that material cannot pass through without coming into close proximity with at least one magnetic element, maximizing the probability of capturing ferrous contamination as it flows past, even at relatively high material flow rates.

Magnet strength is typically specified in terms of gauss rating at the magnet surface, with higher-strength rare-earth magnets increasingly used in modern installations to improve capture efficiency, particularly for smaller or weakly magnetic contaminants that older, lower-strength magnet designs might fail to retain.

Magnet strength and cleaning frequency are the main operational considerations, since accumulated ferrous material gradually reduces a magnet's effective holding capacity for additional contamination, and most quality control programs include scheduled magnet inspection and cleaning as part of routine plant sanitation and equipment protection procedures.

Some installations use self-cleaning magnet designs, where an internal mechanism periodically sweeps accumulated metal away from the magnetic surface into a separate collection area without requiring the magnet to be removed from the process line, reducing the labor and downtime associated with manual cleaning compared to fixed magnet grids that must be physically removed and cleaned.