Improving production efficiency by automating the food industry

The food industry relies on numerous often complex processes, so it is no surprise that the best automation and control technologies developed for chemical and pharmaceutical manufacturing are now helping improve efficiency for a whole new range of users.

Automating production and improving process efficiency are two major objectives of the food industry worldwide. The benefits associated with increased control of raw materials, manufacturing, warehousing and despatch are wide ranging and can have a significant impact on the profitability of food and beverage producers.

Food manufacturing is a complex process, as anyone who works in the industry is well aware. Maintaining the quality of a finished product by monitoring incoming ingredients and regulating the production process precisely are key to the success of a brand and, ultimately, the manufacturing company.

During the past decade of the 20th century, food manufacturers turned increasingly to the process control technology used in pharmaceutical and chemical production. In many respects the industries are similar, all demanding high yields from raw materials as well as a consistent and repeatable quality of finished product. While the regulations covering the manufacture of food and beverages are not yet as strict as those laid down for pharmaceutical production, they are not far behind.

Traceability, conformity and the ability to repeat a procedure precisely from batch to batch not only have legal implications they also directly affect the consumer's acceptance of a product.

As a result of the need for increased quality control and improvements in repeatable production, many food producers are now investing more heavily in automated process control. This type of automation can take many forms, from the fairly simple control of a discrete process to the complete automation of an entire factory or, as one leading supplier of electronic process systems calls it, totally integrated automation (TIA).

Rising to the dough challenge

Warburton's Tyne Bakery in Newcastle is the first bakery in the UK to use a new double dough detection system to help improve the efficiency of its baking lines.

Within the automated process, a specific quantity of dough is placed in each compartment of the baking tray, which is then covered and baked. Occasionally, a double dough error can occur, which results from the overloading of the baking tray. This can have serious implications further down the line, where the baking lids rise higher than normal and can jam in the chain-driven ovens.

To solve the problem, a detection system was designed using compact, M18 ultrasonic sensors developed by Siemens Automation and Drives. Once set, the PC programmable sensors are tamper-proof and their operation cannot be altered except by authorised personnel. The detection system has been incorporated into Warburton's control system so that it either sounds an alarm or stops the conveyor which feeds the ovens.

This simple and straightforward solution demonstrates how process control components and systems can be applied to solve production problems in the food industry.

Control from shopfloor to boardroom

At a more complex level, food manufacturers are now turning to the same company to provide complete turnkey systems capable of automating production. There are many reasons for the recent adoption of process control systems, as Mark Higham, business manager for Siemens Automation and Drives explains: "The food industry is influenced by a variety of issues. Some of these are local, such as the way in which raw materials are delivered and processed. Others, including the efficient distribution of product to supermarkets, have a national importance, while factors such as the cost-effective production of frozen food can take on a global significance.“

The influence of large buyers, such as supermarkets, is also having a marked effect on the food and beverage industry, according to Higham: "Supermarkets are demanding more aggressive pricing, while at the same time expecting improved flexibility of supply. This is forcing food producers to examine ways in which process efficiencies can be improved.“

However, Higham also believes that complex manufacturing procedures, such as those found in the food industry, lend themselves to automation: "The manufacture of foods and beverages often calls for the introduction of a wide range of raw materials. All these need to be carefully checked for quality and consistency. Often, machines can do this more reliably than humans. In addition, the pressures being put on the industry by supermarkets and other large buyers means that distribution channels must be made as efficient and reliable as possible.“

The concept of TIA is now gaining momentum with many of the larger food producers. It enables production line personnel to control the quality of a finished product, such as beer, while the management and finance staff can continually monitor throughput, cost of raw materials and ultimate product yield.

Vertical integration with SAP

Recently KP Foods of Billingham embarked upon a programme of vertical integration. With the arrival of SAP and the need for process information to be more visible, KP Foods examined the way in which data was acquired and used. The installation of a Simatic WinCC supervisory control and data acquisition (Scada) system now enables the company to make better use of data for recipes. This, in turn, improves product quality and raw materials usage.

The experiences at KP Foods are typical of many in the food industry. In some cases, the layer between the shop floor Scada solution and the enterprise-wide information system needs to be filled with a middle layer of technology. Often referred to as Manufacturing Execution System (MES), these solutions are rapidly finding favour where the concept of TIA is being applied to the manufacture of foods and beverages.

In some cases, MES vendors have made a conscious attempt to provide products developed to suit the complex recipe and batch requirements of the industry. A good example of this is ORSI, an Italian MES specialist recently acquired by Siemens for its particular expertise in this area. Already a major supplier to food manufacturers elsewhere in Europe, ORSI is now providing MES solutions for blending and refining processes employed in the UK's food production industry.

Brewers benefit from improved control

The drinks and brewing sector of the market have probably benefited more than any other single area from recent improvements in process automation. There are a number of reasons for this including the high batch value of finished product, the long retention times encountered during manufacturing and the critical nature of the process parameters ­ for example temperature, raw material consistency and mixing.

At Carlsberg-Tetley's Northampton brewery, a number of automation initiatives have been undertaken over the past few years. Today Simatic S7 PLCs (programmable controllers) are at the heart of many of the brewery's process machines, from malt intake onwards. Significantly, the brewer has extended its use of automated systems beyond the physical fermentation and brewing process. The canning and packing lines have also been automated to improve productivity and plant efficiency.

The new brewhouse control system implemented recently at Carlsberg-Tetley is another example of WinCC Scada. Here, using screen mimics on the local operator panels, staff on the production line can now see potential problems arising and take corrective action.

Industry faces up to change

It is not only consumers that drive the food and beverage industry down a particular path. While tastes for particular products change, so the pressures placed on manufacturers by supermarket chains can also have a major impact. Demands for faster, more frequent delivery of smaller stock units, coupled with the need for special packaging to fulfil promotional requirements reduce the time to market for many foodstuffs. This, coupled with the erosion of margins brought about by aggressive central buying squeezes many manufacturers.

Several food producers are now installing process automation systems, such as Siemens Simatic WinCC and PLC solutions, in order to improve yield and streamline both the production and despatch of their product.

Meanwhile other market forces are also at work on the industry. For example, the recently-introduced climate change levy is prompting many food companies to look closely at one of their main areas of expenditure: energy.

This levy is effectively an energy tax that is applied to all industrial users of energy. Very few suppliers of process automation equipment have the global presence and range of technologies to be able to improve energy efficiency at every level of a factory's consumption. However, as part of a recently introduced initiative known as Totally Integrated Power, Siemens Automation and Drives is now providing industry with a complete energy service which stretches from on-site power generation plants right through to building management systems and environmental control. Energy-efficient motors and variable-speed drives, as well as circuit breakers and bus bar installations are now all available from a single source.

In many cases, forward-thinking food manufacturers have already invested heavily in automation.

Higham believes that these companies now face their greatest challenge. "Once an automated solution has been proven, it is important that users adopt a closed loop approach to their process control. This means working in partnership with the suppliers of raw materials, as well as the final customer, to ensure that production and delivery costs are minimised,“ he explained.

It is here, where a customer can obtain information directly on the status of a shipment or order, that the linking of business systems with production systems will really play an important part in the food industry. p

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