Les Hunt visited the world's largest food canning facility to discover how modern electronic and electromechanical safety systems are also being deployed to make it one of the safest operations of its kind in the world
There can be few brands in the world that are as recognisable and as well respected as that of H J Heinz Company Ltd. It would be an easy task to challenge anyone, almost anywhere, to open up their larder or fridge and not find at least one Heinz product there, such is the global presence of this hugely successful organisation.
We might be forgiven for thinking that Heinz is a British company, but it was founded in the USA by Henry John Heinz back in 1869. The first UK sale was in 1886, and manufacturing was first established in the UK in 1905. Today, the largest UK production facility is at Kitt Green on the outskirts of Wigan in Lancashire - and a brief glance at the factory's statistics is sufficient to set the scene for this article.
Kitt Green is the largest food processing plant in Europe and is reputably the largest food canning facility in the world. Cans, in a variety of sizes, are manufactured on site at the rate of around one billion units a year. A large amount of product is processed with many varieties. Clearly, the logistics of moving these cans from the can making plant to the various sterilisation and filling stations, labelling and packaging areas, and warehouse locations present a number of safety issues, particularly in the area of the palletiser/de-palletisers (PDPs), which are the essential 'nodes' of this huge logistical operation.
At Kitt Green there are a large number of PDPs of various types and manufacture, which hitherto have been protected by safety systems to current European standards. Some four years ago, Heinz embarked on a major upgrade to these safety systems, with the aim of bringing all of them to the highest safety level, Category 4 - essentially 'future-proofing' its machines in advance of expected changes in European legislation and increasing safety on site. Heinz at Kitt Green took the lead in this project and is now regarded as a reference site for other Heinz's European plants.
The project to design and install the new safety systems went out to competitive tender and attracted a number of leading sector suppliers. Following a process of elimination, the contract finally went to the US company, Banner Engineering, represented by its UK based subsidiary, Turck Banner Ltd. While the company had completed various projects at the site in the past, the key to its winning the contract was, according to Turck Banner project manager, Richard Amery, largely down to its willingness to tackle the project on a turnkey basis. The company undertook an initial basic risk assessment (including consultations with the machine operators), which was followed by a detailed study undertaken by Heinz' own internal engineering team at Kitt Green.
During Turck Banner's initial assessment, it became evident that while Heinz regard safety as paramount throughout site, the safety systems on individual machines had to be engineered in such a way that, despite a detected operator presence in one part of a machine, operations were free to continue in its other critical parts. The simplest solution would have been to initiate a complete machine shutdown should a potentially hazardous access be attempted in any part of the machine. However, production logistics prevented this.
The solution was to introduce zoning - a method that allows production to continue in one zone of the PDP while another zone has been made safe to allow operator access. Zoning allows, for example, full pallets to be loaded into the PDP by forklift, while de-palletising continues within the other zones of the machine feeding cans back on to the production lines.
The zoning of PDPs is not particularly well defined by existing standards, so Heinz has effectively taken a lead in this area of industrial safety with the installation at Kitt Green.
The engineering design was made more complex as the zoning could not be repeated from machine to machine as each of the machines presented unique zoning requirements because of their differing ages and functionality, revealing the true complexity of Turck Banner's design task. Indeed, the design process required a full appraisal of the individual dynamics of each machine, taking into account such things as machine stopping times, operator access requirements, electrical control circuit designs, current safety systems adopted and other elements that dictated the overall safety configuration.
All the PDPs are guarded by acrylic and/or wire mesh screens with manual access provided by sliding or hinged doors, the positions of which are monitored by coded magnetic switches or electromechanical interlocks. The larger 'open' access points - those providing entry for forklift trucks or the transfer of pallets between sections, which for practical reasons cannot be protected by doors - are monitored by light curtains. E-stops, including both button and rope-pull operated types, are provided at strategic locations for emergency manual intervention.
Turck Banner's installation comprises light curtains from its Micro-Screen and Mini-Screen ranges, together with associated controllers. The Micro-Screen system features tough, ultra-compact light screens ideal for use on production machinery where space is limited. Micro-Screen controllers offer floating blanking, E-stop input and selectable auto power-up. The Mini-Screen system features rugged yet compact light screens suitable for heavy-duty machine guarding applications. Each control panel, comprising both muting and latching controllers is common to most of the machines onsite. Each panel - uniquely configured for individual machines - was built and commissioned off-site and installed during machine possessions at weekends. The time window for installation was necessarily very tight due to production constraints.
The project has taken some two years to complete - no mean feat when you consider the numbers of machines involved and the constraints placed upon the contractor by the production requirements of the plant. Heinz has cut no corners to ensure that its PDPs at Kitt Green meet all the relevant European safety standards that cover such installations. Establishing Category 4 safety level on this scale is indeed a credit to the determination and abilities of both client and contractor alike. Machine safety might today be considered a 'common' industrial activity but, as Henry John Heinz once described the philosophy of his embryonic business: "To do a common thing uncommonly well brings success".