The benefits to the customer are numerous with the Garvens StarWeigh XS checkweigher:

• Foremost is the fact that this unit can handle tall, unstable, and difficult to transfer type of containers
• The unit is designed to straddle the customer’s existing conveyor so installation is quick and easy
• The StarWeigh XS checkweigher automatically times & spaces product for weighing so there is never an issue with having "two packages on the scale at the same time".
• The StarWeigh XS checkweigher is a very small and compact checkweigher so it takes up very little line space. This is particularly valuable in clean room environment
• The StarWeigh XS checkweigher is very accurate, the most accurate checkweigher in the industry
• Depending on the application, the design can incorporate calibrate & re-zero pockets that eliminate any weight drift problems which is an industry first
• Innovation – What is original and/or creative about the new product? What new technologies or design concepts were employed?

Star-Wheel for better Material Handling

Our saying is that "If we can handle the product we can weigh it!". With the introduction of a star-wheel as conveying device through the checkweigher, and straddling the checkweigher over the customer’s conveyor, we have virtually eliminated any transfer problems of the container from the customer’s conveyor to the checkweigher and we have positive control of the container during the whole transfer throughout the checkweigher. Additionally containers do not have to be timed and spaced, that is, separating them from one another to a certain pitch to run them one by one over the weigh platform. These containers running butt-to-butt will hold each other upright. This is significant particularly for small metal canisters or plastic containers used in the pharmaceutical industry which are often top heavy and very unstable, and which if they fall down impact the operation of the production line.

Multiple load cells for higher throughput

Common knowledge when weighing a package on a checkweigher is that when the throughput increases the accuracy decreases! With the use of the star-wheel as conveying device this does not have to be the case anymore. With this arrangement we are able to place multiple load cells side-by-side on a frame below the star-wheel and increase the throughput without impacting material handling or weighing conditions. This is significant as well, since often the limiting factor for the operation of a checkweigher is its throughput. With aerosol cans we have designed a StarWeigh checkweigher integrating 6 load cells, handling a throughput of 400 cans per minute and achieving an accuracy of +/-15mg @ 2σ.

Re-zero and calibration pockets for higher accuracy and no line stop

Load cell parameters will wander over time and so will the accuracy and precision of the load cell overall. If we do not re-zero and calibrate these load cells at regular intervals we will deteriorate the performance of a checkweigher. With a traditional checkweigher arrangement we have to create a "hole" in the product flow to have enough time to re-zero when the weighing conveyor is empty. Typically we like to do that at no more than 15 minutes intervals. In high performance lines a big enough gap is not always present in the line to allow for a re-zero every 15 minutes. Additionally when calibrating a checkweigher one has to stop the line to be able to place a calibration weight onto the weigh conveyor. With the StarWeigh XS checkweigher this is not the case anymore. In the star-wheel we make provision for a pocket that no containers can reach, which becomes our re-zero pocket and another pocket where one and always the same container is trapped in the star-wheel, which becomes our calibration pocket. This means that in every rotation of the star-wheel we can re-zero and calibrate any of the load cells without any interruption of the line. Even more using the customer’s containers in the calibration pocket, we have all the dynamic characteristics of the effective product calibrated into the system.
Another significant aspect with the use of the star-wheel as conveying device is that when placing the container to be weighed onto the load cell by pushing it horizontally, we will not induce any vertical motion beyond natural vibrations produced by the container.
This technology and the load cells chosen, has allowed us to achieve accuracy better than +/-10mg @ 2σ weighing gold and silver coins at 120 coins per minute. This is the first and only checkweigher in the market that calibrates itself on a continuous basis while operating.

Short Unit for Minimal Line Space:
The round star-wheel as a conveying device does not need a lot of space. Hence we can design a very compact unit that fits over the customer’s conveyor. This is particularly valuable in clean-room environment where space is of a premium.

Flexibility for Different Container Sizes:
On many production lines, customers run numerous size and weight containers which creates difficulties for conventional checkweighers. The conventional checkweigher must be sized for the heaviest package and this always causes poor performance (with package handling and accuracy) on the smaller lighter weight packages. With the StarWeigh XS checkweigher, we can and have incorporated the dual scale option where we utilize one lighter capacity weigh cell for the smaller product and one larger capacity weigh cell for the larger product. This allows the StarWeigh XS to maximize accuracy for lighter and heavier products all in one checkweigher.