Checkweigher conveyor engineering
Keep the weighing result attached to the right pack.
The critical task is not simply firing a pusher. The system must preserve pack order and carry each checkweigher result to the exact product at the reject point. Conveyor speed, distance, acceleration, product pitch and sensor positions all affect that tracking window.
Smooth transfers and controlled spacing also protect weighing performance. Unstable packs, back pressure or a poorly aligned transfer can create repeatable nuisance rejects. We assess the approach, weigh section, discharge and reject conveyor as one product-handling sequence.
Choose a reject action that suits the pack.
A pneumatic pusher is often suitable for stable cartons, tubs, bottles and trays. Air-blast rejection can suit light packs at high speed, while a drop flap or retracting belt can create a controlled downward reject route. Product trials are used to check clean separation across the pack range.
The rejected product can enter a guarded or lockable bin. Bin-present, full-bin and access-open sensing may be added where the operating requirement calls for secure containment or a fail-safe line permissive.
Retrofit checkweigher reject conveyors
A reject module can often be integrated with a suitable existing checkweigher or packaging line. The survey checks the available straight length, conveyor height, belt speed, product gap, electrical and pneumatic services, inspection outputs, guarding and access for cleaning and maintenance.
The final acceptance test should challenge good and failed products across the operating range, including minimum and maximum packs, normal speed, start-up conditions and the agreed fault responses. Read the reject conveyor selection guide for the application details that help this review.
Typical checkweigher applications
- Underweight and overweight packs
- Missing-component weight checks
- Food and beverage packaging
- Cartons, bottles, tubs and trays
- New or existing production lines
- Verified reject containment
Checkweigher reject system FAQs
How does a checkweigher reject system work?+
The checkweigher classifies each weighed product, the control system tracks that result to the reject point, and a timed mechanism removes the failed pack. A separate sensor can confirm that removal occurred.
Which reject method is suitable after a checkweigher?+
Pneumatic pushers suit many stable packs, air blast can suit lightweight products, and drop-flap or retracting-belt systems can suit products that need downward or gentler removal. Product trials confirm the choice.
Can checkweigher rejection be added to an existing line?+
Often, yes. The review must confirm usable conveyor length, stable transfers, product pitch, signal availability, guarding, reject containment and the line response to a fault.
What is reject confirmation on a checkweigher line?+
Reject confirmation is an independent signal that the identified failed pack entered the reject route within its expected time window. If confirmation is missing, the system can alarm or stop the line.