Hygiene-Compatible Components: Encapsulated slip rings in packaging machines for the food processing industry

Many applications use slip rings to transmit data and energy from a fixed to a rotating machine element. The must be as fast-rotating and low-maintenance as possible. In addition, if they are used in the food processing industry, they have to meet the hygienic requirements.

Food packaging prevents the food from contamination and from pests. But packaging does much more:  it preserves the shape, the colour and the taste, and it protects our environment by ensuring longer food preservation and preventing the waste of food. In addition, it contributes to the reduction of the additives used with the food, such as for example for its preservation. So, packaging brings many advantages; always provided it is of high quality, it meets the requirements of the product and the extremely stringent standards and hygiene provisions pursuant to the German Regulation on the Hygiene of Foodstuffs, in short LMHV.

All critical operations on the way to the consumer must be continuously monitored, documented and ensured and guaranteed by means of appropriate procedures. These provisions do not only apply to the finished product, but to the whole manufacturing process, including the packaging machines, their components and all of the materials used during production.

The tasks of a slip ring

Kubler expanded its Transmission Technology products portfolio decisively, especially for the use in this highly regulated sector. The Kubler slip rings used in packaging machines operating in the food processing area resist reliably the conditions of the working environment and ensure smooth functioning and long service life. For the new Kubler slip rings SR060E and SRI085, this is true both for the material of the drive unit and for all interface components such as connections and seals.

In packaging devices, slip rings are in charge of the rotary transmission of energy, signals and data between stationary and rotating platforms. The new Kubler SR060E has been designed for up to three load and two signal transmissions; it shows its strength in many different applications: from heating and monitoring of sealing rollers in flowpack machines, in stretch film wrapping machines or balancing machines, and up to textile machines.

For an efficient cleaning

Microbiologically perfect products are a vital aspect for every food manufacturer. The Kubler slip rings have all essential features to meet the hygiene and cleaning safety requirements in aggressive environments. Thanks to their smooth, straight surfaces - without any undercut - they are particularly easy to maintain and simple to clean. Their oval round housing is fully encapsulated, safely protecting the machine against abrasion dust. This is important since the protection of the processed food requires that no machine element shall produce any substance that might be harmful to health or have a negative influence on the taste or smell during the production process.

For easy and safe cleaning, the materials of the machine elements must resist aggressive detergents and disinfectants, and any reaction of materials must be excluded. They must be corrosion-resistant, mechanically robust and their surface must be completely insensitive.  
 
Both the new Kubler slip ring SR060E and the SRI085 are fully encapsulated and therefore not only safely protected against contact, but also, thanks to their two-chamber system, perfectly insulated and particularly easy to clean. A trend in mechanical engineering is the increasing maintenance optimisation with the goal of building plants requiring particularly little maintenance or even no maintenance at all.

The contact material used in the Kubler SR060E slip ring strongly supports this trend: the slip ring equipped with silver, bronze and precious metal contacts (contact oil-free) requires maintenance only all 100 million revolutions. This maintenance is then minimal, consisting simply in vacuum-cleaning the dust. Even in the case of continuous operation, which is generally the case today with this kind of machines, this value is practically negligible.

Regarding maintenance optimisation, the new SRI085 slip ring relies on non-contact signal transmission to the moving machines; it operates totally without mechanical wear.

For the benefit of the customer

Today packaging machines operate at high speeds. This fast pace results, for example for heat-sealing of blister packagings, in increasingly short contact times for the films. The high rotary speeds of 500 and even 800 RPM of the new Kubler slip rings compensate these high speeds without difficulty. The load current dimensioning of up to 20 resp. 25 amperes allows very short heating times and thus an optimal temperature regulation - even for shortest contact times.

The IP64 protection level is ideally suited to resist all kinds of cleaning processes. And, as regards flexibility and easy installation, these slip rings have the best arguments for their use: flat plugs, fastening screws and anodised aluminium parts minimise the installation time for the customer.