Filling line for yogurt: Hygienically designed with plastic plain bearings

Profile

• What was needed: iglidur J bearing bushings, drylin R linear round guides, igubal spherical bearings, iglidur J plain bearings, energy chains
• Requirements: High availability in 24/7 operation, very high hygiene requirements, resistance to at least daily cleaning (aggressive cleaning agents, superheated steam, high pressure), lubrication-free, FDA approval
• Industry: Beverages sector, bottling plants
• Success for the customer: Our bearings are maintenance-free and wear-free. There are also polymer materials that have been specially developed for food processing machinery and have the appropriate approvals. For these reasons, miromatic design engineers have been using a wide range of our plain bearings for more than ten years.

Problem

Michael Rothdach GmbH in the Allgäu region of Germany is a renowned machine and plant manufacturer specialising in the processing, filling and packaging of food products - with a focus on dairy products. Under the brand name miromatic, the European market leader develops mixing systems for fruit yoghurt as well as bucket filling systems for food products such as yoghurt, mustard, ketchup and sauces. The filling plants are individually configured on the basis of the customer requirements, whereby the designers can resort to a modular system of individual standard stations. There are, for example, functional units for the process steps such as provision of empty containers, filling process (with weighing or inline flow measurement), lid supply and separation, lidding, sealing and labelling. All these modules vary and are therefore linked according to customer requirements.
Developers have to meet high availability requirements for all systems. A 24/7 operation is the rule rather than the exception. In addition, very strict hygiene requirements apply. Dairy products are very critical in this regard. That is why miromatic has developed various hygiene and sterile concepts, such as a line for the aseptic filling of dairy products under sterile air blanketing. All systems are designed to withstand at least daily cleaning with the usual methods (more or less aggressive cleaning agents, superheated steam, high pressure). In addition, the exposed drive elements are lubrication-free to prevent contamination, and the components and materials used are FDA-approved.

Solution

The plain bearings made of high-performance polymers perfectly fulfil this requirement profile. They are maintenance-free and wear-free and form a good friction pairing with aluminium and stainless steel. Approved polymer materials have also been developed specifically for food machinery construction. For these reasons, miromatic designers use a wide range of our plain bearings, and have done so for more than ten years.
Here are some examples: bearing bushes made of iglidur ensure precise guidance of rotary and linear movements on various guiding and adjusting elements (see picture 1 below). Depending on the application, housing bearings, such as the drylin R linear round guide here, are also used and simplify both production and assembly (picture 2). In ball screws, igubal spherical bearings compensate for misalignments (pictures 3 and 4). And the easy-to-use format adjustment at the sealing stations is implemented with iglidur J plain bearings (picture 5). Last but not least, our energy chains are also used, which supply energy and signals to the moving axes of the mixing and filling systems (also picture 5).
The material used from the iglidur range is decided according to the application. Apart from the "all-rounder" iglidur J, however, the bearings also have to meet special requirements for temperature, resistance to cleaning media or moisture absorption. There are special iglidur polymers for this.

Picture 1: Container sorting – iglidur J bearing bushes ensure precise guidance in the linear stroke.

Picture 2: The lid sorting is implemented by drylin R linear guides. These pillow blocks consist of two parts and simplify the installation of the systems.

Picture 3: Lead screws are mounted in igubal spherical bearings to compensate for misalignments.

Picture 4: Detailed view of igubal spherical bearing as support for the lead screws

Picture 5: The height adjustment of the filling station is implemented in the vertical linear stroke with iglidur J plain bearings. One of our plastic energy chains ensures safe cable guidance.