Pianoro (BO), Italy, 22-1-2014 — /EuropaWire/ — In 2013, a well-known American supplier of veterinary products purchased a new version of the filling and closing machine Millennium 120 from Marchesini Group. TheMill120-2 was created from the standard single channel linear version. The new version adds innovative solutions to close PE tubes containing ATEX products. The machine is loaded with plastic tubes with conical caps that are filled with a liquid product at low doses (between 0.6 and 7ml), and at runs at a speed of 100 ppm.
The functioning of Mill 120-2 in 7 steps
1. Tubes loading on the machine
The printed PE tubes are loaded in bulk into a hopper of about 200 liters of capacity. A selection conveyor belt transports the tubes towards the Robovision unit, which is produced and patented by Marchesini Group. The robot is equipped with four axes of movement and a vision system, which guides the pick-up head to collect and correctly orient each tube, and then it places it on a specially sized plates that are fixed to the belt transport system.
The plates are fixed by means of a quick release system, and the correct positioning of the tubes are continuously controlled by precise sensors. The transport is equipped with a special reject station, pressurized air is used to remove the tubes that are not correctly placed or without cap. The tubes are then placed in a pair in their individual pucks by means of a tilter driven by a brushless motor, which then holds the tubes pneumatically until their complete insertion into the transport system.
The orienting group is equipped with two brushless motors provided to orient the tubes reading the marking, or recognizing a cavity formed on the upper circumference of the tube.
The system for tubes internal cleaning has two plundering blower nozzles, a PALL filter for the filtering of compressed air, and a vacuum pump with a special filter for the recovery of removed particles.
The filling group is dedicated to liquid products and therefore it uses two rotary valves made of stainless steel 316L. The system allows a tolerance in the order of + / – 5% for doses of 0.6 ml. The hopper is placed on a loading cell which provided to enable the product dosage and to reload the hopper when the detected weight drops below the minimum set. In this way it is able to avoid any contact with the product and maintain the hopper under a constant nitrogen flow. The inert gas flushing is a necessary condition considering the ATEX characteristics of the product.
5. Group for nitrogen introduction
The nitrogen is also flushed into the tube either before or after filling and immediately before its closure. The whole filling and sealing area is under nitrogen flushing, and a special sensor controls the efficiency of the fume extraction system measuring the internal/external pressure differential of the machine.
6. Ultrasound sealing
To avoid the presence of surfaces with high temperatures, typical in the hot jaws or hot air systems, the machine is equipped with an ultrasonic sealing system. A high frequency power generator is provided to produce the necessary heating only on the surfaces to be sealed, avoiding raising the temperature of the sealing group. A cooling pneumatic group is provided to reduce the residual temperature on the sealing blocks during the machine stop.
7. Tubes outfeed towards the downstream machine
The tubes are equipped with a conical cap, which is pushed towards the tube body to punch the diaphragm allowing liquid irrigation from the conical cap itself. For this reason, the tube reject system is obtained by means of a pick & place, which picks up tubes from the individual pucks and directs them to the corresponding inclined belt oriented “cap forward” taking them from the sealing area, and thus avoiding any pressure caused by pushing or pulling on the plug.