Slice is right for Welsh cheese maker
19 Dec 2006
AVC manufactures and pre-packs a large variety of quality Welsh-branded cheese products at its facilities in Lampeter, Ceredigion. The company uses locally sourced raw milk in its products, which include Cheddar, Curd, Red Leicester and double Gloucester cheeses.
For the manufacturing operation, cheese is taken up into towers, known as block formers, where the cheese is cut into blocks. The previous weighing system was unreliable so that the cheese sliced in the towers was coming out in varying weights. The problem was linked to the original weight controller being unable to communicate back to the PLC to make the necessary corrections.
To address these issues, the cheese maker opted for a solution from Applied Weighing to replace the existing load cells and weight instrumentation for the tower weighing systems with a closed system in a feedback loop.
Within the new setup, each tower weighing system works in conjunction with a load cell junction boxes, which is designed to allow easy monitoring of the load cell performance and ensure their correct functioning. The load cells were used with special weighing assemblies chosen for their ease of installation, reliability and suitability for weighing in harsher environments.
The three original weight indicators were also replaced with a single weight controller, the Model 920i. This controller shows a graphic weight display for each tower and a single Profibus output was provided to communicate with the PLC.
Alongside the three towers is a conveyor line, which comes back on itself in a loop. A checkweigher on the conveyor belt checks the weights of the cheese coming out of the towers. The original checkweigher was upgraded by using another Model 920i weight controller to perform a dynamic weighing programme.
This weight controller notices changes in weight from each tower individually and has a single Profibus output to communicate with the existing PLC. Therefore, it is now possible for the PLC to correct any changes in weight by changing the cheese cutter settings in the towers.
The checkweigher is fully useable as a standalone unit, but information can also be sent to and from it via LAN/Profibus/RS232. Information about many different products can be stored in an internal databank. The stored product information cannot only include tolerances but also information about product routing and belt speeds. The checkweigher is therefore suitable not only for ‘in-weight’ checks but also for classification and sorting for a wide variety of different weights and sizes.
This closed system has allowed the system to get within 7g accuracy of the 25Kg in the towers. This degree of accuracy has impressed Aeron Valley as it is extremely precise and has enabled them to have greater consistency in their cheese production.
By installing the new system Aeron Valley are now able to control weights more accurately. Being able to control the weights in the towers better allows them to produce a softer cheese and, therefore, produce the best quality cheese possible.
Having operated the system at the factory for a number of months, Edward Evans, chief engineer at Aeron Valley Cheese: The system “has enabled our production team to manufacture an even greater quality of cheese and will continue to do so for many years to come.”