April 2000
In today's modern food and drink processing plants the emphasis is moving towards computerised control systems that enable efficient communication between different production line sectors and ensure more speedy fault diagnosis. The vital links within these systems are control cables. Dr Russell Smith, Managing Director of Lapp Cable, highlights some of the applications and specific environments that require specialist control cabling and advises on specification.Match the cabling to the environment
Specifying the correct control cable to work with the various systems now available for managing the manufacture and processing of food and drink is as important as choosing the system itself. Reliability is crucial, as control cable failure at any point in the production process will result in inconvenient and expensive machinery downtime. Lapp Cable has developed a range of highly flexible and durable control cables to cope with the specialist requirements of such demanding industries.
Processing environments are often harsh and the production lines subject to constant movement, vibration or abrasion. As a result the cables - extending out from control panels around the line to process control devices - must offer a high degree of flexibility and durability. Lapp's polyurethane sheathed cables offer excellent wear and tear resistance as well as being extremely flexible.
Food and drink preparation and processing environments demand the highest standards of hygiene and these high standards have to be met by all equipment, including cables. Hydrolysis resistant and microbe proof compounds are the ideal answer. Appropriately specified, the cable sheaths resist microbe growth, and are hydrolysis resistant which is particularly useful during cleaning and hosing down operations. The special polyurethane sheathing compound also provides increased protection against chemicals such as cleaning fluids.
Another common requirement for control cables within the food processing industry is the ability to withstand hot and cold environments. Extremes in temperature prohibit the use of standard PVC sheathed cables, which degenerate in these conditions. Lapp's FEP and PTFE insulated and sheathed cables provide increased protection from harsh thermal conditions, allowing the cables to operate in temperatures ranging from minus 190°C to plus 260°C. Again, durable polyurethane sheathed cables are the best choice for applications exposed to abrasion in both wet and cold conditions. Polyurethane offers far greater durability than PVC cables with a steel wire braid which in certain circumstances may be susceptible to degeneration and in extreme situations rusting, thus necessitating more regular replacement.
Cables may also be required to offer mechanical or chemical resistance. Ironically, the 'environmentally friendly' biodegradable oils, vegetable oils and water mixable cooling lubricants are very aggressive when they come into contact with normal PVC and elastomeric sheaths. In this instance, the specially developed OLFLEX-FD® NATUR range of cables provides the required protection, enabling cables to be used for the flexible connection of control devices on conveyor, assembly and transfer lines in areas where biodegradable oils are present.
To ensure total confidence in cable performance and durability, the perfect combination of cable, gland and connector is essential. A protected cable is all but useless if used in conjunction with an inadequately rated gland - the mechanical device that ensures protection of the cable at its point of connection. All glands carry an IP rating of two digits: the first classifies the protection against contact with foreign bodies, and the second classifies water protection. So, for example, an IP65 rating denotes that the gland is protected against the ingress of dust and against water jets from a nozzle. Many of Lapp's glands are tested to IP68 making them completely dust and water resistant.
Quick identification of hundreds of different cables can simplify a maintenance engineer's work and, more importantly, make it much safer. Specialist marking systems have been developed to clearly label cables and these too have to be selected to suit specific applications. For a food processing environment, stainless steel markers, such as Lapp Cable's Fleximark®, are ideal. They provide a rustproof, chemical and fire resistant labelling solution and are unaffected by heat, cold, corrosion, acids or chemicals. Within the cables themselves, the choice between colour or number coded cores, provides safe and reliable identification of circuits even in applications requiring as many as 41 individually identified cores.
For the specifier looking for cabling solutions to particular problems, Lapp Cable's new Applications Guide, entitled "Control cables for all environments", is an indispensable and highly informative tool. For each specific application, the Guide identifies the appropriate Lapp Cable product and details its primary performance requirement (eg, oil resistance), its secondary performance (eg, microbe resistance) and other associated characteristics.
The Lapp Group is a leading global manufacturer of control cables and accessories. In addition to ÖLFLEX® control cables its brands include UNITRONIC® (Data and Bus cables), SKINTOP® (Cable Glands), EPIC® (Cable Connectors), FLEXIMARK® (Cable Marking Systems) and HITRONIC® (Fibre Optic Cables).
