A cross-belt sorter is an advanced conveyor-based automated sortation system used in various industries to handle and direct items such as luggage, apparel, parcels, packages, and mail. This system uses a series of independently operated short conveyor belts mounted transversely along the main track, [1] known as cross-belts that are organised in a loop, to sort items quickly and accurately to their designated destinations. Cross-belt sorters are widely utilised in logistics, e-commerce and postal services due to their high efficiency, throughput, and accuracy.
There are a variety of different cross-belt sorters—each industry and each cross-belt sorter manufacturer can have unique products. Nevertheless, the standard two are horizontal cross-belt sorters and vertical cross-belt sorters. In both cases, current generations employ linear induction motor technology—this means they are simpler to operate, maintain, and endure less mechanical wear over time. [2]
The main components of a cross-belt sorter include:
The cross-belt sorter operates in several stages:
There are typically three main connections required to the cross-belt trains to enable operation. High-end cross-belt sorters adopt non-contact technology in favour of minimal maintenance. This means little or no wear occurs, providing a highly reliable system and reducing lifecycle cost, but results in a slightly higher capital cost to other technologies.
Linear synchronous motors (LSM) are used in high-end sorters as they require little maintenance, are non-contact and can provide accurate acceleration, deceleration or maintain a speed. Although speeds up to 3 m/s are reported, sorter speeds of up to 2.5 m/s are typically used for parcel applications to ensure no fly-outs of lighter items (Items becoming airborne during acceleration or transit). Additional LSM’s are typically added to a track for redundancy, therefore, should a LSM become inactive, there is sufficient propulsion provided by the remaining LSM’s to ensure no loss of performance.
Alternative contact solutions adopt motorised wheels that propel a flat plate under the sorter through friction.
Inductive power transfer (IPT) uses a magnetic field to transfer electrical energy without contact. Alternatively, a wheel with a motor on the carrier, generates power to the cells. An often cheaper but higher maintenance solution uses a Busbar system and brushes.
Contact types of activation rely on mechanical actuators to activate the cells, though typically the ejection point requires to be a fixed position resulting in less dynamic ejections and operates at lower speeds and throughputs.
Industrial Wi-Fi is typically used as this provides non-contact communication that is not disrupted by dirt or debris. Alternative technologies include Infrared.
Cross-belt sorters offer several advantages:
Cross-belt sorters are employed in various sectors, including: