We were approached by a major food manufacturer in East Anglia to investigate potential improvements to their process and handling equipment used in the production of cooked rice which was then used in pre prepared meal production.
Our customer was experiencing a very high scrap rate (> 15%) using their existing equipment. Our engineers attended their site in order to completely understand the processes and reasons for generation of the scrap. This study also included all up stream and down stream processes so that any suggested solution took into account all of the associated requirements.
The original system utilised traditional wire baskets with a perforated sheet mat secured to the bottom. It was established during inspection and experimentation that the scrap was being caused by burst bags which were as a result of 2 faults.
In sufficient head room above the tray base to allow sufficient expansion of the bag
Damage to the existing trays causing the bags to be punctured during the cooking process.
The trays supplied by Craven and Co. Ltd were different in construction to the wire basket design as they are of a sheet construction and have an effective internal free height of 42mm when close stacked.
A weight transfer system through a series of height control pins directly to the stillage rather than through the baskets reduced the stress. This reduced the tray damage sustained and also allowed the ability to use two different product heights by alternating the pins being used.
The existing stillages were also modified which included placing some small packer pieces in the corner of the stillage or removing the central packer already present on the stillage.
We were able to achieve a complete re-design of trays and stacking system. The new system has the following advantages;
- With the same overall height and hence retort loading, an increase of 20% in the free head height was achieved. This reduced the scrap rate to 0% and achieved a payback period of 8 months.
- The ability to use two different heights due to new pin system, allowing two different products to be processed on the same equipment.
- An improved stacking system transferred all the weight to the base stillage using a series of pins, rather than transferring the load through the trays themselves. The damage to the trays was therefore virtually eliminated. This resulted in an increase life of the trays (approx 3 times the original).