01How narrow belt diverting works
The sorting surface is a bed of many narrow belts running side by side across the width of the line, in the direction of travel. A small parcel rides on several belts at once. To divert it, the belt groups beneath and beside the parcel are driven in a pattern — running, stopping or driving differentially — that walks the parcel diagonally off the main flow into its chute, while parcels for other destinations continue straight. There is no arm to swing and no wheel row to swivel; the surface itself does the steering.
That surface is the smalls advantage. A mailer or small carton is always fully supported by several belts, so it cannot tip into a roller gap, stall between sections, or be missed by a diverting mechanism sized for bigger freight. Light items that a pusher would flick, the belt bed carries and places.
02Where narrow belt fits
Smalls streams in e-commerce fulfilment, postal and courier flows, and the small-parcel tail of a mixed operation that deserves its own line instead of struggling through a carton sorter. Narrow belt sections also serve as destination diverters downstream of a dimensioner in compact measure-and-sort cells for small goods.
The honest limits: narrow belt is a small-parcel technology. Large, heavy cartons belong on cross-belt carriers or behind wheel sorter rows, and a mixed operation often runs both — carton sorting on one line, smalls on a narrow belt line, each stream on the surface that handles it best. The parcel sorter page sets the range side by side.
03Feeding a narrow belt sorter
Smalls arrive in bulk — sacks, totes and gaylords of unsorted mailers — so the upstream stages matter as much as the sorter: a singulator (with stack separation where items arrive overlapped) to create the gapped single file, and identification sized for small labels. The sorter then executes destinations at the pace the smalls stream demands, which is counted in items per hour far beyond carton-line rates. Line design starts from your smalls profile: item size range, stream volume at peak, and destination count.