Aseptic milk filling

A volumetric filling system specifically for the aseptic filling of milk products has been developed by Krones, based in Neutraubling in Germany.

The Volumetric VODM-PET enables the volume of the product being handled to be precisely specified by means of an inductive flowmeter. This makes it particularly suitable for applications where dimensionally accurate containers, such as PET bottles, are being used. Hygienic or cold aseptic filling is possible in combination with a cleanroom. A further feature that makes the system highly suitable for aseptic bottling processes is an option whereby the filling function can be carried out without touching the bottle. An electro-pneumatic control system also enables the user to preprogram reproducible filling steps precisely matched to the product. The liquid is stored in a tank that is connected to the filling valve via the product feed pipe (which incorporates the inductive flowmeter for measuring the volume of product flowing through the pipe). The bottle is guided to the filling valve by a neck handling feature. This filling system does not require any lift cylinders since filling is performed in non-contact mode, giving the advantages of optimised hygiene coupled with a maximised filling angle. As soon as the bottle has been transferred to the filler, the electro-pneumatic control system opens the filling valve, thus triggering the filling function. After the pre-programmed volume of liquid has passed, the flowmeter transmits a signal to the machine's control system that causes the filling valve to close.

Direct control All steps in the filling or cleaning process are controlled by direct pulses via the control unit in the electronic component cabinet. These can be stored in memory at a centrally located user terminal and retrieved at will. Product is fed without foaming and either a membrane valve with filter or bellows valve without filter can be used. The VODM-PET milk filler is available with six different diameters, ranging from 1800 to 4320mm for 50 to 120 valves. In line with the dairy industry's stringent hygiene requirements, the version for exclusively still products features a greatly reduced number of function valves and is easy to clean. The cleaning procedure is supported by automatic CIP cups. The isolator design presupposes sterilisation of all the components inside it, and of the inflowing media and packaging components arriving. This PET-Asept process (a concept that is already well-known and proven in the beverage industry) has meanwhile found customers in Europe and Asia among producers of milk and milk-based beverages. Since the beginning of 2003, seven of these lines have been commissioned, ranging in capacity from 12,000 x 1.0-litre bottles per hour to 38,400 x 0.6-litre bottles per hour. The Brescia Spa dairy in Italy has been using this technology for a number of years. The first shared project came to fruition in 1999, when the dairy decided to market its fresh milk in PET bottles. In September 2003, the dairy's project for aseptic bottling of UHT milk in PET containers took shape with the installation of a PET-Asept line with isolator technology and a new Krones Contiform S8 blow-moulding machine. This recently went into operation and has already been successfully validated.

Special feature Another user of the VODM-PET system needed to be able to fill up to four different flavours simultaneously. A special feature was incorporated in the filler whereby every fourth valve fills the same product, thereby avoiding elaborate downstream order-picking of four mixed products in a single tray. To make this possible an intelligent line control system was required. This collects data from the line and writes back work instructions for the operators on the touch-screen of each machine's control panel. The line is able to fill transparent, coloured and opaque PET containers with volumes from 250 to 500ml and a size-38 neck. The range of operations carried out at these dairies clearly demonstrates the ability of Krones to act as a supplier of complete systems for entire lines – from the stretch blow-moulding machine through to the filling process all the way to the dry end.