Automation in the Food Industry, 1991

This book is designed to be everything its title suggests-a practical guide to automation within the food industry. It is the first book to offer practical advice on what can be a most bewildering subject in an industry where the use of effective automation is of paramount importance. There are many books dealing with the theory and practice of control systems in both the food and other industries. However, these tend to offer too much detail in both areas to be classed as overviews, or cover too much of the more obvious detail and gloss over, or avoid, the elements where the decisions are hard-even though these are the areas which are fundamental to successful and expansive projects. This book identifies those elements of any automation scheme which have to be considered first, and that form the foundations for any successful project. The editorial introduction outlines the content of the book and is a useful starting point. Examples are used, wherever possible, to show what can be done, how it can be achieved, and what to avoid. A glossary of definitions is included at the end of the book. All the chapters have been written by engineers, with many years' experience in this field, who have been able to express their views freely. The result is a book which covers the key areas of the subject, using a minimum of the technical jargon with which this subject abounds, in a readable, practical manner.

1 Introduction to food processing.- 1.1 Introduction.- 1.2 Raw materials handling and storage.- 1.2.1 Categories of materials.- 1.2.2 Identifying incoming materials.- 1.2.3 Control and information requirements.- 1.2.4 Example of tank farm.- 1.2.5 Example of flour blending.- 1.2.6 Example of milk reception and storage with CIP system.- 1.3 Primary processing.- 1.3.1 Batch versus continuous processes.- 1.3.2 Modularity.- 1.3.3 Mixing.- 1.3.4 Evaporators and heat exchangers.- 1.3.5 Vacuum and pressure cooking.- 1.3.6 Variable flowrates.- 1.3.7 Effluent.- 1.3.8 Dispensing and container handling.- 1.3.9 Shaping and forming.- 1.3.10 Example of a confectionery assortment.- 1.4 Secondary processing.- 1.4.1 Packaging systems.- 1.4.2 Machine control and coordination.- 1.4.3 Assembly automation.- 1.4.4 Example of confectionery assortment packing.- 1.4.5 Finished goods storage and despatch.- 1.5 Weighing and metering.- 1.5.1 Weighing.- 1.5.2 Metering.- 1.5.3 Example of a ‘loss in weight’ metering system.- 1.6 Summary 27 Further reading.- 2 Total systems.- 2.1 Introduction.- 2.2 Current systems concepts.- 2.3 General requirements.- 2.3.1 The pragmatic approach.- 2.3.2 Utilise existing technology.- 2.3.3 Identify measurable benefits.- 2.3.4 Commonality of use.- 2.3.5 Transfer of information.- 2.3.6 Utilise a modular platform.- 2.3.7 Resilience.- 2.3.8 Adaptability and expandibility.- 2.3.9 Use industry recognised vendors.- 2.3.10 Maintainability.- 2.3.11 Allow for external factors.- 2.4 Food processing industry issues.- 2.4.1 Conversion factors.- 2.4.2 Quality.- 2.4.3 Safety.- 2.4.4 Cost.- 2.4.5 Repeatability.- 2.5 Manufacturing process system.- 2.5.1 Pre-production issues.- 2.5.2 Production issues.- 2.5.3 Post-production issues.- 2.6 Total systems.- 2.6.1 Functional blocks.- 2.6.2 Method of implementation.- 2.6.3 Benefits of total systems.- 2.6.4 Engineering the facility.- 2.6.5 Training and education.- 2.7 Examples of total systems approach.- 2.7.1 Example 1: the design phase.- 2.7.2 Example 2: the planning phase.- 2.7.3 Example 3: the implementation phase.- 2.8 Summary 46 Further reading.- 3 Integrated factory systems.- 3.1 Introduction.- 3.2 Integration objectives.- 3.3 Integration phases.- 3.4 Process control and factory automation.- 3.5 Human interface.- 3.6 Summary 57 Further reading.- 4 Specification for success.- 4.1 Introduction.- 4.2 Control system concepts.- 4.3 Hardware requirements.- 4.4 Software requirements.- 4.5 Case studies.- 4.5.1 Soft drinks plant.- 4.5.2 Edible oil plant.- 4.6 Summary.- References.- 5 Computers in control.- 5.1 Introduction.- 5.2 Types of computer.- 5.2.1 Programmable controller.- 5.2.2 Personal computers.- 5.2.3 Mini- and mainframe computers.- 5.2.4 Summary of computer types.- 5.3 SCADA and DCS systems.- 5.3.1 SCADA system.- 5.3.2 DCS equipment.- 5.4 Stand-alone controllers.- 5.5 Three term control.- 5.5.1 The purpose of three term control.- 5.5.2 Algorithm based three term control.- 5.5.3 Auto tuning.- 5.6 Hardware configuration.- 5.6.1 Single system.- 5.6.2 Single controller with remote I/O.- 5.6.3 Hierarchical system.- 5.6.4 Intelligent field sensors.- 5.7 Secure system configurations.- 5.7.1 Dual processor single I/O.- 5.7.2 Dual channel.- 5.7.3 Triple (or more) channels.- 5.7.4 Single channel with non-computer back-up.- 5.7.5 Safety considerations.- 5.7.6 Reboot and auto synchronising.- 5.8 Operator interfaces and maintenance aids.- 5.8.1 Operator interfaces.- 5.8.2 Maintenance data.- 5.9 Summary.- 6 Operator interfaces.- 6.1 Introduction.- 6.2 Operator functions.- 6.2.1 Supervision and alarm handling.- 6.2.2 Process overview.- 6.2.3 Production control.- 6.2.4 Maintenance.- 6.2.5 Which system?.- 6.3 Serving the person behind the machine.- 6.3.1 Ergonomics.- 6.3.2 Picture hierarchy.- 6.3.3 The need to know and the need for speed.- 6.3.4 How much information?.- 6.3.5 Alternatives to keyboards.- 6.3.6 Control-room design.- 6.4 The right system on the right level.- 6.4.1 The local operator interface.- 6.4.2 Centralised operator interface systems.- 6.4.3 Mimic panels.- 6.4.4 Monochrome VDUs.- 6.4.5 Printers.- 6.4.6 Interaction devices.- 6.4.7 Colour graphics.- 6.4.8 Management-level operator systems.- 6.5 Future operator interface systems.- 6.5.1 Presentation, simulation, evaluation.- 6.5.2 Back to the mimic, down to the process level.- 6.5.3 Integrated functions.- 6.6 Summary 118 Further reading.- 7 System accuracy and reliability.- 7.1 Introduction.- 7.2 Accuracy.- 7.2.1 General concepts.- 7.2.2 Why is accuracy important?.- 7.2.3 Terminology.- 7.2.4 System configuration.- 7.2.5 Processor arithmetic capability.- 7.2.6 Analog and digital signals.- 7.2.7 Digital integration.- 7.2.8 Example of weigh system accuracy.- 7.2.9 Example of metering accuracy.- 7.2.10 Example of level measurement accuracy.- 7.2.11 Estimation of overall system accuracy.- 7.3 Statistical quality control.- 7.3.1 Automated data acquisition.- 7.4 Reliability.- 7.4.1 General concepts.- 7.4.2 System reliability analysis.- 7.4.3 Mean time between failure (MTBF).- 7.4.4 Failure rate.- 7.4.5 System availability.- 7.4.6 System configuration.- 7.4.7 Failure mode analysis.- 7.4.8 Series system.- 7.4.9 Redundant system.- 7.5 Software quality assurance.- 7.5.1 Software failure.- 7.5.2 Software error rate.- 7.5.3 Assuring software quality.- 7.5.4 Software quality assurance policy.- 7.5.5 Analysis and design methodology.- 7.5.6 Programming standards.- 7.6 Summary 148 Further reading.- 8 Achieving integration.- 8.1 Introduction.- 8.2 Integration.- 8.2.1 Background.- 8.2.2 Why integrate?.- 8.2.3 Information transfer requirements.- 8.2.4 System coordination.- 8.2.5 Connecting elements together.- 8.2.6 Defining integration.- 8.3 Feed forward.- 8.4 Feedback.- 8.5 Production management information.- 8.5.1 Resource optimisation.- 8.5.2 Manufacturing information.- 8.5.3 Material audit.- 8.5.4 Quality assurance.- 8.5.5 Telemetry systems.- 8.6 Summary.- 9 Computer enhancements.- 9.1 Introduction.- 9.2 Background.- 9.2.1 Why do you want a computer anyway?.- 9.2.2 Technology is well in advance of what you can buy.- 9.2.3 Who is going to specify and program the automation?.- 9.2.4 Who is going to maintain the system?.- 9.2.5 The push behind current developments.- 9.2.6 State of the art: what does it mean?.- 9.3 Hardware enhancements.- 9.3.1 Miniaturisation at operator and plant level.- 9.3.2 The rate of development for speed and size of processors.- 9.3.3 Transputers.- 9.3.4 Parallel processors.- 9.3.5 Multi processors.- 9.3.6 Dual systems.- 9.3.7 Dual standby systems.- 9.3.8 Dual and triple redundant systems.- 9.3.9 Inventions still waiting for technology to catch up.- 9.3.10 Production methods.- 9.3.11 Adaptive control.- 9.3.12 Opto electronics.- 9.3.13 Intelligent peripherals and input/output.- 9.4 Software enhancements.- 9.4.1 Standardisation.- 9.4.2 Software developments.- 9.4.3 Management information systems.- 9.4.4 Data acquisition and SCADA packages.- 9.4.5 Computer-aided process engineering.- 9.5 Hardware and software together.- 9.5.1 Reduced instruction set computers.- 9.5.2 Computer integrated manufacture.- 9.5.3 Factory of the future.- 9.6 Summary.- Further reading.- 10 Expert or knowledge-based systems.- 10.1 Introduction.- 10.2 Experts.- 10.3 Non-experts.- 10.4 Building expert systems.- 10.5 Technology.- 10.6 A practical guide.- 10.6.1 The very hard way: write it yourself.- 10.6.2 The quite hard and very very expensive way: use an AI toolkit.- 10.6.3 The cheapish but still fun way.- 10.7 Summary 195 Further reading.