Cape Town-based Seravac is a bulk supplier of enzymes and related products to the diagnostic, pharmaceutical, biotechnological, research, wine, food and beverage industries. The company is acknowledged as one of the world's largest producers of the enzyme Peroxidase, extracted from horseradish roots. In addition to a range of specialty enzymes, Seravac also offers custom development and manufacturing services. These products are all manufactured to strict FDA-approved standards.
The original plant was officially opened by Dr Chris Barnard in 1961 and was recently acquired by Good Hope Holdings. Under the new management, there has been a substantial increase in international demand for the company's products. After carrying out feasibility studies, it was decided to install new facilities with a high degree of automation and to streamline the processes involved. This would increase productivity and efficiency at the plant and at the same time bring manufacturing in line with the company's ISO 9002 certification.
Seravac's project manager, Hennie Wagener, says that one of the major challenges to the upgrade was to ensure that the company's FDA accreditation was retained. This meant that the desired throughput improvements could not be achieved at the cost of changing the manufacturing processes in such a way that would necessitate a complete and costly re-accreditation. This, in turn, provided some real challenges to Ram-Tec Systems in the implementation of the automation and control system.
Previously, most processes were run largely on a manual basis, particularly so that the products could be laboratory-checked at the various production stages. Manufacturing standards for this type of product meant these check points had to be retained.
A great advantage of automation can be lost if the plant is dependent to a large extent on manual input and the operators lead the process. Some parts of the factory, such as the Coffin Filters (where the filtration residue is needed for the final product), simply could not be automated and the mixture of full and no automation made the system all that much more complex.
While some of the latest automation technologies were used in the control system design, it was seen that the easiest and most efficient method to cater with Seravac's production requirements was with tried and tested scada technology. "After considering the various packages available, we recommended Wonderware's InTouch to the client," says Malcolm Heathfield Ram-Tec project manager. "InTouch provided us with a flexible, stable platform as well as ease of use from a configuration and user point of view. We also had a growth path for planned future expansion of the plant and importantly, an opening for the installation of a full industrial sequel server to be installed at a later date."
In the initial phase, the sequel server capabilities already built into InTouch were used to provide traceability on the product and the process. Two separate database utilities were set up using standard MDB file structures. CIP process information with duration and date time stamp was saved in one, while the second stores information on the batch being produced and added ingredients. Both these functions produce automated traceability in place of manual logging.
The factory has two separate manufacturing processes - the horseradish plant (HRP) and pharmaceutical and diagnostic factory (PDF). The InTouch scada provides a total overview of both plants. At the PDF plant an Allan-Bradley SLC500 PLC controller is located with Flex I/O for MCC control. This PLC also supports an ASI bus network to solenoid field boxes as well as analog instrumentation. These IP65-rated devices were mounted directly in the field with no enclosure for added protection. Heathfield says supplying an enclosure for these robust devices would have led to additional and unnecessary cost.
At the HRP system an HMI and separate Allan-Bradley SLC 500 PLC have been installed. A DeviceNet link connects the PDF and HRP PLC systems.
Development and commissioning of the HRP and PDF systems had to be done within tight schedules to ensure minimum downtime. The combination of technologies chosen ensured that the strict deadlines were met in this instance with both plants completed on schedule.
For more information contact Mike le Plastrier, Futuristix Advanced Control Systems, 011 723 9900, [email protected], www.futuristix.co.za
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