Food Engineering

FieldReports: Recipe for a kitchen upgrade

March 22, 2003
Automating its batch processing helps Langeberg Foods increase the efficiency of its operations

The only problem with being an industry leader for decades is the tendency to continue with the same success formulas for too long.

In the case of Langeberg Food Processors -- one of the oldest and best-known prepared food makers in South Africa -- many of its plant operations were too labor-intensive and decentralized for efficient production. Hence, company management decided to study all operations to find ways of optimizing production.

The company's Boksburg plant in suburban Johannesburg was chosen as the test facility for a complete renovation of the Kitchen Plant, where jams, brines and sauces that are intermediate ingredients of end-use products are made. Langeberg manufactures a diverse range of foods, including mayonnaise, tomato sauce, jams and jellies, and a variety of canned vegetables.

As part of the Boksburg plant upgrade, the company and its system integrator, Hatch Africa (Pty) Ltd., researched software-based production systems and selected modules from the Windows-based FactorySuite software from Wonderware Corporation in Irvine, Calif. After purchasing a development toolkit from Wonderware distributor Futuristix, the team began designing systems that would incorporate InTouch process visualization software; an InBatch flexible batch management system; and Industrial SQL Server real-time relational database. This last module was intended to provide historical data on each product batch and facilitate easy-to-use structured queries into the data for process optimization.

"Our overriding goal was to have a modern integrated Kitchen Plant with real-time control," explained Langeberg project manager Evert de Vries. "We want to have a Plant that could run at least 10 different products simultaneously, coordinated with production of at least 17 different recipes that result in the intermediate ingredients for those products. Our goals were to reduce the labor content of each product, reduce the cost to make each product; reduce production waste and raise the quality of our products."

With the upgrade complete, productivity gains have improved dramatically. In fact, Langeberg needed to renovate its filling and seaming lines in order to keep up with increased product flow.

Batch production

The new Kitchen Plant has several batch preparation areas that include a wide range of tanks, vessels, pipes, manifolds, valves, mixers and other equipment -- all controlled automatically using Siemens Programmable Logic Controllers (PLCs) and InTouch operator workstations. "All recipes are initiated by the system and we tend make one product at a time in each area because we want consistency of throughput for each product," said Kitchen Plant production manager Sean Elton. "We need flexibility to handle various products according to seasonal growing patterns. The staff know in advance what product batches to initialize in order to adapt to the fresh produce and jam concentrates coming in."

Many of the most commonly used raw ingredients are supplied to the Kitchen Plant via seven piping systems that help automate the addition of starch, tomato puree, vinegar, brown syrup, white syrup, oil and hot water to the appropriate batch. These ingredients are discharged automatically via manifolds into the tanks, autoclaves and mixers appropriate to the particular recipe. Langeberg and Hatch Africa set up approximately 125 product recipes and another 30 Clean-in-Place (CIP) recipes in standard sets of production "trains."

Production priorities are set within the system and each batch is scheduled on a per-shift basis, with InBatch providing the ability to schedule as many as 16 recipes for processing at any given time.

All ingredients arrive in tanker trucks or in drums and are diluted or mixed in preparation areas to produce the correct sugar concentrates for delivery to the batching areas. A separate spice room is used to store all dry ingredients that are added by hand at specific phases during a batch. Langeberg staff pre-batch the proper weights and combinations of spices for particular product batches so they can be added simultaneously by the floor operators.

Each batch run uses a similar procedure in which the first ingredient is typically 90 percent of the water required for the product, followed by other ingredients and then the final 10 percent of the required water. InBatch checks for equipment availability and starts available batches immediately. Each product recipe includes a number of phases and these are run in sequence, issuing instructions to the PLC for specific actions to be controlled at every phase. Certain phases require operator intervention (i.e. the hand addition of small amounts of spices) and the process is halted until the operator has accomplished the task and entered feedback data on a nearby operator interface panel. This data entry step verifies that every step of the recipe has been completed.

Complete batch genealogy

The operator messages are stored locally in the operator workstations and are also sent to the InBatch Server where the process controller can view the messages that are queued for each of the workstations. In the event of a workstation failure on the Kitchen Plant floor, the process controller is still able to instruct the operator verbally of the next step to ensure that the batch continues without interruption. At the end of each batch, the recipe is updated to "done" status and InBatch proceeds to the next production batch.

All historical data on each batch run are maintained in an IndustrialSQL Server database. Batch record logs provide traceability from the finished products all the way back through the production process to the ingredients consumed. These logs include information such as start/stop times, quantities, ingredients and even operator details for use in maintaining product genealogies as well as for historical analysis to optimize system performance using standard structured query statements. Both the InBatch and database systems utilize dual hard drives so that all data is 100 percent backed up. The SQL machine also has a DAT tape backup.

Langeberg has an off-line laboratory that tests samples of every batch for pH and Total Dissolved Solids (TDS). If either of these is too high or too low then the operators are prompted to take corrective action. In the case of certain brine batches, the InBatch system makes the adjustments automatically and then prompts the Kitchen Plant operator to resample. All test results are recorded in the InsdustrialSQL Server data base for traceability purposes.

All Clean-in-Place operations are managed by InBatch as well to optimize efficiency and throughput. CIP operations can take place at two levels, either in tanks or in the pipe lines, so that either can be cleaned while the other is in use.

"One of the significant benefits of using the InSQL data base module is that it makes it easier to optimize our processes and better integrate other systems, such as computer-aided maintenance and time and attendance," Elton said. The integrated nature of the FactorySuite software also permits management to add new capabilities easily.

Based on successes we've had in the Kitchen Plant using the FactorySuite software, we've decided to standardize on Wonderware software at all five of our major manufacturing plants in South Africa," de Vries noted.