A belt conveyor parcel sorting system uses continuous conveying, parcel identification, position tracking, and automatic diverting to transport and route parcels to designated destinations. Belt conveyors move parcels between operating stations, while sorting mechanisms receive commands from the control system and transfer parcels to the required sorting lanes.
A belt conveyor mainly performs the transportation function and does not necessarily provide automatic sorting by itself. A complete parcel sorting system usually combines belt conveyors with sliding-shoe, swivel-wheel, pop-up transfer, or other sorting equipment.
Main components of a belt conveyor parcel sorting system
A complete parcel sorting conveyor system generally consists of conveying equipment, sorting mechanisms, identification and control systems, and discharge equipment.
Belt conveyor
The belt conveyor is the basic transportation section. It typically consists of a conveyor belt, drive pulley, return pulley, idler rollers, tensioning device, frame, and drive motor.
Common belt materials include PVC and PU. The appropriate material depends on parcel weight, conveying speed, surface-friction requirements, operating environment, and cleaning requirements. The drive pulley moves the belt continuously, while the return pulley changes its direction and the idlers support the belt and conveyed parcels.
Some conveyor lines are also equipped with belt-misalignment sensors, tracking devices, guide rails, and protective structures to reduce belt deviation and handling problems.
Sorting mechanisms
Sorting mechanisms transfer parcels from the main conveying path to designated branch lines. Depending on the equipment design and application, common options include sliding-shoe sorters, swivel wheel sorters, pop-up roller transfers, and pop-up chain transfers.
These mechanisms use different operating principles and have different parcel-handling requirements. They are not all installed directly into a conventional belt conveyor.
Identification and control system
The identification system collects parcel identity and logistics data. Common devices include fixed barcode scanners, QR code readers, OCR vision systems, and RFID readers.
Barcode scanners read the codes printed on parcel labels. RFID readers collect information from electronic tags attached to parcels or carriers. Some systems also use DWS (Dimensioning, Weighing and Scanning) equipment to measure parcel dimensions and weight.
The control system typically includes PLCs, industrial computers, sensors, and higher-level sorting management software. It retrieves the assigned destination from the identification results and determines when to activate the sorting mechanism based on parcel position and conveyor timing.
Sorting outlets and discharge equipment
Sorting outlets receive parcels after they have been diverted. Common arrangements include chutes, side conveyors, collection bags, totes, and roll cages.
Each outlet may correspond to a delivery area, transportation route, or downstream handling station. More automated systems may also include full-container detection, chute blockage sensors, and fault alarms to monitor discharge conditions.
Operating process of a belt conveyor parcel sorting system
After entering the sorting system, parcels usually pass through induction, identification, task assignment, position tracking, automatic diverting, and exception handling.
Parcel induction and conveying
Parcels enter the belt conveyor through manual loading, unloading conveyors, or automatic induction equipment. When parcels are unloaded in bulk from roll cages, pallets, or containers, an upstream singulator may be installed to separate items that are stacked or touching one another.
Singulation equipment creates a more consistent gap between parcels, allowing them to enter the identification area as individual items. This helps improve scanning and downstream sorting performance.
Identification and data acquisition
As parcels pass through the reading station, fixed scanners read the barcode or QR code on each shipping label and transmit identification data, such as the tracking number, to the sorting control system.
If DWS equipment is installed, parcel dimensions and weight can also be measured during conveying. In systems using RFID, readers collect the corresponding electronic tag data.
The identification result is generally matched with shipment information in the backend system to determine the parcel's destination. The full delivery address is not necessarily encoded directly in the barcode.
Sorting assignment and position tracking
Based on the identification result, the control system assigns the parcel to a designated sorting outlet. Photoelectric sensors, encoders, or other detection devices track its position along the conveyor.
Position tracking keeps the identification data associated with the correct physical parcel. When the parcel reaches the activation zone of the sorting mechanism, the system sends the divert command according to the predefined conveyor timing.
A position-tracking error can cause a parcel to be mis-sorted or missed, even when its barcode has been read correctly.
Automatic diverting
When a parcel reaches the assigned position, the control system activates the corresponding sorting mechanism and transfers it from the main conveyor path to the target outlet.
Depending on the equipment design, the diverting action may involve lateral pushing by sliding shoes, directional transfer by swivel wheels, or lifting and lateral transfer by pop-up rollers or chains.
After diverting, the parcel enters the designated chute, branch conveyor, or collection area.
Exception handling
When a barcode cannot be read, shipment information cannot be matched, parcel tracking becomes invalid, or a sorting outlet is blocked, the system may route the parcel to an exception-handling area.
Operators can rescan the shipping label, verify the shipment data, or inspect the parcel condition. After the issue has been resolved, the parcel can be returned to the automated sorting flow.
The exact response may involve an alarm, a local conveyor stop, recirculation, or manual diversion, depending on the control logic and system configuration.
Continued conveying of unsorted parcels
Parcels that do not receive a divert command at the current outlet continue along the main conveyor to subsequent sorting points. After passing the final sorting station, parcels that have not been diverted may enter another sorting line, a designated collection area, or a downstream dispatch process.
How common sorting mechanisms work
Belt conveyors can be combined with different sorting technologies. The following three mechanisms are commonly used in logistics sorting systems.
Sliding-shoe sorter
A sliding-shoe sorter typically uses a chain or slat-based conveying structure with multiple sliding shoes mounted on the conveyor. The shoes move along guide structures to divert parcels laterally.
When a parcel reaches its assigned sorting position, the control mechanism activates the corresponding shoes. The shoes push the parcel toward a side sorting lane. After the diverting movement, the shoes continue along the conveyor and return to their operating positions for subsequent sorting tasks.
This design can handle cartons, totes, and various packaged items. It is suitable for logistics systems with multiple sorting outlets. Its throughput depends on conveyor speed, shoe spacing, parcel dimensions, and outlet layout. A single maximum throughput figure should not be applied to all sliding-shoe sorters.
Swivel wheel sorter
A swivel wheel sorter uses a group of steerable wheels or rollers to change the conveying direction of parcels. When a parcel reaches the designated diverting point, the control system changes the wheel orientation, moving the parcel toward a side branch conveyor.
Some models use servo motors to control wheel steering, while others use pneumatic or alternative drive arrangements. Swivel wheel sorters can be installed as independent diverting modules along a conveyor line and are used where parcel flows need to be redirected to different branches.
Parcel compatibility depends on the wheel arrangement, contact surface, base stability, and load capacity. Some models can handle mailing bags and small parcels, but soft packages, irregular items, and parcels with uneven bases should be tested under actual operating conditions.
Pop-up transfer sorter
A pop-up transfer unit is generally installed at a designated point along the main conveyor. When a parcel needs to be diverted, the lifting mechanism raises rollers, belts, or chains until they contact the bottom of the parcel. The transfer unit then moves the parcel laterally onto a branch conveyor.
Depending on the drive arrangement, the equipment may use pop-up rollers, pop-up chains, or pop-up belts.
These systems are commonly used to change the direction of cartons, pallets, and other items with stable supporting bases. The allowable load must be determined by the lifting mechanism, conveying surface, motor capacity, and rated equipment specifications. It should not be assumed that every pop-up transfer unit supports the same load.
How to select a suitable parcel sorting mechanism
Different sorting mechanisms have different load-carrying arrangements, diverting methods, and installation requirements. Selection should be based on parcel characteristics and the operating requirements of the complete conveyor system.
Parcel dimensions and packaging: Check maximum and minimum dimensions, weight, base geometry, and packaging materials to ensure that parcels can move reliably through the conveying and diverting sections.
Required throughput: Determine the target processing rate based on parcel volume per hour, conveyor speed, and parcel spacing. Confirm that both the sorting mechanism and discharge equipment can handle the required volume.
Number of sorting outlets: When multiple outlets are required, consider sorter arrangement, outlet spacing, and the control system's ability to assign sorting tasks.
Available space: Check conveyor length, elevation, branch directions, maintenance access, and connections to existing equipment.
System integration: Confirm that identification equipment, PLCs, sorting software, and higher-level logistics management systems can exchange information correctly and support the required exception-handling functions.
Belt conveyors provide continuous parcel transportation, while sorting mechanisms change the conveying path. These components must work together with identification, tracking, and control systems to form a complete automated parcel sorting solution.
In addition to precision mechanical components for logistics conveying and sorting equipment, Hansheng Automation provides custom CNC precision machining services. We manufacture non-standard precision components according to customer-supplied drawings and support individual parts and small-batch production.
