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. This 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. 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. These were as a result of 2 faults:
- In sufficient head room above the tray base to allow sufficient expansion of the bag
- The existing damaged trays were puncturing the bags during cooking
The trays supplied by Craven were different in construction to the wire basket design. They are of a sheet construction and have an effective internal free height of 42 mm 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. The tray damage reduced, and alternating pins allowed for two different product heights.
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;
- The free head height increased by 20%, with the same overall head height. This reduced the scrap rate to 0% and achieved a payback period of 8 months.
- The new pin system can use two different heights. The same equipment can therefore produce two different products.
- An improved stacking system transferred all the weight to the base stillage using a series of pins, rather than transferring the load throught the trays themselves. This eliminated damage to the trays. This resulted in an increase life of the trays (approx 3 times the original).