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French company adopts Krones’ PETAsept bottle technology

Krones has introduced an entire process engineering and PETAsept bottle technology to provide maximum product flexbility for milk and senstivie beverages at the French Laiterie de Saint Denis de l’Hotel (LSDH).

The privately-owned company will be using Krones’ PETAsept L line to fill Ultra-High Temperature (UHT) milk in PET bottles. In addition, Krones also supplied the entire process-engineering kit, making the milk bottling process into an integrated, fully coordinated whole. The line also produces and fills a huge multiplicity of fruit juices and various other drinks as dealer’s brands.

Up until 2006, LSDH had largely been concentrating on aseptic cartoning. With ten cartoning machines and eight lines, the plant in Saint Denis de l’Hôtel produced approximately 800,000 Brik packages a day. However, due to the constance flux in the market and demand patterns, LSDH decided to incorporate aseptic PET bottling into its range. It has also simultaneously invested in two lines; one inline bottling operation with an hourly output of 18,000 containers without its own blow-moulder and another line concentrating on large volumes with its own blow-moulder.

Krones’ process-engineering project comprises of asystem invovling the preparation and UHT sterilisation of milk, milk-based mixed drinks, juices and soy milk, which supplies the 18,000-bph PETAsept L line, producing high and low-acid beverages with pH values ranging from 3.8 to 8.0. The line can also produce 100 per cent fruit and vegetable juices, squashes, semi-skimmed milk and skimmed milk as white or aromatised milk, plus soy milk.

From a tanker-truck unloading station, milk or concentrate is passed into one of the three mixing and storage tanks, each holding 180 cubic metres, while simultaneously being cooled down to a temperature of four degrees Celsius. The exact quantity is measured by a flow metre and integrated into the feed pipe. The three tanks are connected to a double-seat valve rack, providing an option for having one tank filled, the next one used for product preparation and the third cleaned. A centrifugal pump passes the product via an electro-magnetic flow meter to the UHT system, which has an output of between 9,000 and 18,000 litres an hour, depending on the level in the downstream aseptic tank.

Deaerating, homogenising, sterilising

Once preparation is complete, the finished product is passed into an enclosed 500 litre release tank. The product is preheated and then fed into the pressure deaeration system where the dissolved oxygen content is minimised. An aroma-recovery system makes sure that losses of volatile aromatic substances are kept as low as possible. At the deaeration unit’s outlet, a nitrogen injection feature has been provided. Following deaeration, the product can be homogenised at a maximum pressure of 200 bar in a homogeniser. All control functions are continuously recorded and handled by the central programmable logic control (PLC).

The shell-and-tube heat exchanger assures product sterilisation, either at 95 degrees Celsius (for fruit juices) or at 145 degrees Celsius (for milk), plus cool-down to four degrees Celsius or 25 degrees Celsius, depending on the product to be sterilised in each case.

To minimise energy consumption, the heat exchanger’s recovery rate is 85 per cent with a UHT treatment of milk at four degrees Celsius through 145 degrees Celsius and back to 25 degrees Celsius. Depending on the product involved, a total of three heat-holding zones can be connected, so as to assure treatment times of three, thirty or sixty seconds.

From the UHT system, the product is passed to the insulated sterile tank with a useful capacity of 30,000 litres. The tank is fitted with an agitator, whose speed is regulated by a frequency controller. Aseptic valves with a vapour seal assure the system’s sterility. The temperature of these sterile seals is monitored and recorded.

Seamless transition to the PETAsept line

According to Krones, the transition from process-engineering to bottling kit is seamless. The PETAsept line is supplied via short paths from the steriliser, rinser, isolator, filler and closer with sterile water and peracetic acid, and with product. A Contiform S12 accommodated in an adjacent room feeds the freshly blow-moulded PET bottles into the line via an AirCo conveyor.

LSDH has moulds for six different container shapes in stock, three round ones, plus one square 1.0-l bottle, one square 1.5-l bottle and one round 0.25-l bottle. The round 1.0-l containers for milk have been developed in conjunction with the preform supplier PDG-Plastiques under the designation of “LacPET” as double-layered ones, with a carbon-fibre-reinforced inside layer for better UV protection. The Contiform handles this special type of preform with no problems at all, just as the “normal” PET preforms with a 38 mm neck finish. LSDH produces and fills about 900,000 containers per week on this line, run in three-shift operation.

Directly downstream of the PETAsept L line, a Checkmat inspects the filled and closed containers for correct fill level and closure position. The Accutower installed after that makes sure the line can “take a breather” at need, providing up to five minutes of buffer time. A Contiroll wrap-around labeller is responsible for the container dress, which is then inspected by another Checkmat. Now, in the infeed to the Variopac TFS tray/film-wrapper there’s an option for distributing the containers among up to six lanes. The Variopac produces 1×3, 2×3 and 2×2 shrink-packs, for example, or 3×2 units on trays. After that, it’s possible to fit the packs with a handle in an applicator before a multi-divider turns the shrink-packs to the appropriate position for layer formation. And last but not least, a Robogrip palletiser loads the pallets, either as euro- or half-pallets. This machine is also able to load half-pallet-sized full-depth trays (erected from blanks and fed to the Robogrip by an additional machine) with loose bottles on half-pallets. Two of these half-pallets at a time are placed on one europallet.

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