Maintenance-free sterilisation machine

Lubrication-free linear technology and polymer slewing ring bearings in sterilisation machines

Today, ever more designers are relying on lubrication-free and maintenance-free plain bearings made of plastic. Customised or catalogue solutions are available from simple to the most complex tasks. This is also evident in the design of a sterilisation machine of the company OPTIMA consumer GmbH as part of a packaging line. Chemical resistance, weight savings and freedom from lubricants: these were the most important requirement criteria.

Profile

  • What was needed: drylin W profile rail guides, drylin R linear shafts, polymer slewing ring bearings, xiros plastic ball bearings
  • Requirements: The bearings operate like the machine five days a week and must have a long service life. They must function reliably when used with aggressive chemicals and be particularly lightweight.
  • Industry: Packaging industry
  • Success for the customer: The lubrication-free bearings made of plastic guarantee a long service life due to low coefficients of wear and friction. Among other things, they are lightweight, corrosion-resistant and their clearance is adjustable.
Sterilisation machine General view of the sterilisation machine.

Problem

OPTIMA consumer GmbH is a supplier of filling, closing and packaging machines. The globally positioned company offers everything that makes the dosing, filling, packaging and sealing of food, chemical and cosmetic products easier, safer and more economical. As a rule, these are special machines.
For one customer, the machine manufacturer has developed a sterilisation machine for cleaning the interior of canisters. Live cultures, which serve as additives for foodstuffs, are filled in. Absolute sterility must be guaranteed during filling. After initially designing a system for bottles with a capacity of one litre or 250 millilitres, a second system was later developed for five-litre or 25-litre canisters.
The sterilisation machine, which is in operation five days a week, is positioned at the beginning of the packaging line. Its core is a rotary tool. The canisters are clamped in, lifted and rotated 180 degrees. They then pass over the disinfection nozzles, are sprayed, turned back and set down on a belt. At this point, the disinfectant must act for a few seconds, which can be achieved by the filling process or the cycle times. the cycle times. Two 25-litre canisters are handled per minute.
In order to kill any bacteria present in the canisters, liquid chlorine dioxide, which is extremely aggressive, is used for disinfection. For this reason, the chemical resistance of the components is important. But it is also about energy efficiency. Thus, the total weight and the ease of movement of the system play an important role. The heavier the plant, the more sluggish the entire movement process. For this reason, motors and drives are designed smaller if less weight has to be moved. It is therefore clear to the design engineer that, given the complex requirements profile, only plastic can be considered as a material for the lubrication-free bearings.
 

Solution

Our lubrication-free bearings made of plastic guarantee a long service life due to low coefficients of wear and friction. Among other things, they are lightweight, corrosion-resistant and their clearance is adjustable. In addition, materials are available that enable applications under water, at high temperatures, in the food sector and/or in aggressive environments.
OPTIMA consumer GmbH also relies on this tribo-optimised polymer technology for plain bearings. Introduced on the market under the name 'iglidur', they have been intensively researched and improved for 30 years.
In the rotary tool of the degerminator, the suspension of the entire unit consists of a tough drylin W linear guide system as a double profile and manual clamp for higher holding forces to fix the position. The absence of lubrication makes the system extremely insensitive to dirt. The linear guide is a special part that was milled out to save weight and provided with recesses according to customer requirements. As a bearing arrangement, a pillow block with adjustable clearance proves its efficiency.
A polymer slewing ring bearing (PRT) is used as a counter bearing to the rotary cylinder that rotates the individual canisters. A special feature is the space-saving square flange, which allows direct installation on flat surfaces. A particularly lightweight drylin R precision aluminium tube shows its strength as a counter support. Linear pillow blocks such as shaft blocks and floating bearings combine to ensure that the tube cannot rotate freely. The chemical-resistant and low-wear iglidur J is used as material in all sliding elements.
The designer also relies on the material 'iglidur X' in many of his projects. It has an extremely high chemical and temperature resistance of up to 250 degrees Celsius.
„On the one hand, they are well-engineered and more cost-effective for us to procure than stainless steel bearings. And our customers don't have to keep expensive lubricants or even cleaning agents on hand. In addition, there are no disposal costs, which add up in the long run.“

Thomas Franke, Design Engineer at OPTIMA consumer GmbH on the igus polymer plain bearings
drylin W linear bearings The drylin W linear guide with pillow block has been manufactured as a special part according to customer drawings.
drylin R floating bearings Two drylin R floating bearings in combination with hard anodised aluminium shafts serve as torque support.
Bearing of rotary tool A polymer slewing ring bearing (PRT) with a square connection is used to support the rotary tool.
Polymer ball bearings The polymer ball bearings are also used in a range of packaging machines. They are tough, smooth-running and often replace more expensive metallic rolling bearings.