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Wrapping up bottled water

Capitalizing on an underground source of superb water quality, Earth20, Culver, OR, began bottling water in single-serve bottle sizes in 1991. It added a new rotary line and a 5-gal line in 1996. Since then, it has added a 1-gal line and a retail polyethylene terephthalate line running 12-, 16.9-, 20- and 24-oz bottles as well as 1- and 1.5-L sizes at speeds to 300 bottles/min. The retail products were originally packed in corrugated trays, but the company recognized the economic and ecological benefits of eliminating corrugated, and last spring it replaced its case packer with a Brandpac BPMP-5000 film multipacker from ARPAC Group (www.arpac.com). One of the most versatile units on the market, the wrapper runs 4-, 6-, 8-, 10-, 12- and 24-packs at Earth20.

The Brandpac Model BPMP-5000 is a continuous-motion, print-registered bottle-wrapping system that multipacks products in unsupported bundles (it can also overwrap trays, but Earth20 no longer runs trays). Earth20 is running nondistortion-shrink, high graphics printed film at speeds up to 70 multipacks/min. Supplied by Shields Bag & Printing (www.shieldsbag.com), this high-performance film, which is available printed in up to eight colors, is designed specifically as an alternative to paperboard and corrugated packaging for multipack bottles, cans and containers. It features exceptional clarity with excellent shrink and strength characteristics that allow it to be used as a standalone, unsupported package. The "bull's-eye" opening has been engineered to provide the utmost in strength for consumer handling and convenience.

The Arpac wrapper features a bottom overlap-sealing system, which is a new design that eliminates a seal bar. It overlaps the leading and trailing edges of the film beneath the grouped bottles, and they are then sealed in the shrink tunnel.

During PD's visit, the line was running 20-oz bottles, which were being bundled in a 4x6 configuration. The PET bottles, which are supplied by Ball Corp. (www.ball.com), are delivered to the wrapper in bulk on a conveyor, where they have formed six lanes, and enter the machine through a servo-driven shuttle grouper that maintains the lanes. The bottles are released from the grouper in groups four bottles deep to achieve the 24-bottle count.

A single roll of film is mounted on the side of the intermittent-motion machine and enters the machine perpendicular to the direction of bottle travel. It passes over a 45-deg roller that changes its direction to coincide with bottle travel and then passes over a series of dancer rollers that pull the film from the roll and feed it up into the wrapper. After each wrapping cycle, a brake stops the film movement to maintain registration. A servo-driven, serrated knife cuts the film, which has its top facing downward, to the proper length needed to wrap the package as it enters the wrapping section. The pull rolls and the knife are driven by servos from Parker Hannifin Corp. (www.parker.com/packaging).

A flight bar, which is connected to chains on both sides of the machine, comes around behind each group of bottles as it leaves the grouper and pushes it into the wrapping section. The cut piece of film is fed up through a gap between the grouping conveyor and the wrapper conveyor, and the edge is pushed beneath the bottles as they travel onto the wrapper conveyor. Another flight bar traveling faster than the bottle conveyor then lifts the trailing edge of the cut film, folds it over the tops of the bottles and pulls it down over the bottles. The motion of the bottles pulls the leading edge of the film beneath them to the point where it overlaps the edge placed beneath the bottles previously. The bottles then enter the shrink tunnel, which tightly shrinks the film around the bottles and creates a very tight bundle. The wrapper includes a print-registration system that achieves a 1/16-in. accuracy, and it can return to this accuracy within two wrapping cycles after an upset. An interesting feature of the registration system is that it needs no registration marks on the film. It detects the edge of the printing on each section of film.

The shrink tunnel features a three-zone blower that quickly and evenly shrinks the film around the bundle. The unit utilizes a low-volume side and top hot-air flow to reduce film ballooning in the shrink tunnel.

The wrapper incorporates an Allen-Bradley programmable logic controller from Rockwell Automation (www.rockwellautomation.com) as well as a color-touchscreen operator interface with message display and self diagnostics. The unit includes preprogrammed settings for conveyor speeds, timing and temperature settings for fast, accurate setup when changing product size and film. Quick changeover is facilitated by color-coded spacers for the infeed lane guides and a splicer rack for the film. Other machine features include a machine-mounted jib crane to ease film loading, a low-film alert to warn of a film changeover and central-point lubrication that allows for routine maintenance without stopping production.

"The wrapper performs well," says plant manager Manny Martinez. "Arpac assisted us with the installation, and and we're satisfied with the Arpac equipment."

The PET bottles at Earth20 are received on pallets. After depalletizing, they are conveyed into an enclosed room for increased sanitation where rinsing, filling, capping and labeling take place. To start the operation, bottles enter an air rinser from Bevco Conveying Systems (www.bevco.net). At the entrance to the rinser, the bottles are picked up by parallel-gripper conveyors running at a higher speed than the infeed conveyor to pull a gap between the bottles. The bottles are inverted around wheels and moved over air jets, followed by a vacuum header. The bottles are then turned right-side-up around another set of wheels, and are deposited on the outfeed conveyor. The speed of this conveyor closely matches the speed of the grippers to ensure the maintenance of a gap between bottles. This gap is read to determine a backup on the line, and if a backup occurs, the rinser, including the infeed conveyor, will stop before the backup reaches the machine. The machine will automatically restart when the backup clears.

A sensor at the infeed of the rinser reads the presence of bottles, and if there are no bottles for a preset length of time, the air will shut off. As soon as bottles are detected again, it will restart before the bottles hit the air header. A switch at the outlet of the rinser instantly stops the machine if a bottle jam occurs. As this is usually caused by an unusual backup condition, the outfeed of the machine must be cleared and the rinser manually restarted. A pressure switch shuts down the machine if the rinse medium hits a low-pressure condition. With this switch, the rinser will not run if the operator fails to open the infeed valve on the unit on startup. It will also shut down if air pressure is lost in the middle of a run.

The gripper spacing is changed by using a handwheel to adjust for different bottle sizes. The spray header is also adjusted with a handwheel to set the nozzle height in relation to the bottle neck.

Click here to enlarge.

Bottles are then conveyed to a monobloc gravity filler/capper from Fogg Filler Co. (www.foggfiller.com) that has 48 filling stations and 16 capping heads. During operation, a timing screw at the inlet of the filler meters the bottles into a starwheel that, in turn, places them onto individual spring-loaded bottle pedestals. As the machine rotates, each pedestal raises the bottle up against a seal on the bottom of the gravity-fill valve, which incorporates a vent. A guide on the bottom of the valve ensures that the top of the bottle is centered against the valve. As the pedestal continues to lift the bottle, it pushes up the valve sleeve, and filling commences. This continues as the filler rotates until the product reaches the bottom of the valve sleeve. As the bottle fills, air is displaced into the top of the filler bowl through the vent. The filling cycle is set so that the product reaches the bottom of the valve sleeve as the filler rotation brings the bottle near the machine-discharge starwheel. At this point, the bottle pedestal descends, allowing the fill valve to close, and the bottles travel into the discharge starwheel.

As the bottles leave the filler, liquid nitrogen is injected by a dosing system from VBS International, Inc. (www.vbsinternational.com) to pressurize the container. The system has a precision vertical dosing head mounted between the filler and the capper. A sensor detects a bottle entering the dosage zone and initiates the injection of a very small dose, about 0.10 g, of liquid nitrogen at a temperature of -320 deg F into each bottle. The nitrogen rapidly expands volumetrically as it changes from a liquid to a gas inside the bottle.

The capper on this line incorporates a Sidel-Aidlin cap sorter/feeder from Sidel (www.sidel.com). Caps are dumped into a floor hopper from which a flighted, inclined conveyor lifts them up for transfer into the capper. The conveyor is designed so that it will only transport caps with the open side facing out. Caps with the open side facing in drop off the flights back into the hopper. Near the top of the conveyor, the caps discharge into a chute that delivers them to the capper. Caps that pass this point drop down a plastic tube back into the hopper.

Caps in the chute are fed to a gate on the rotating capper. When a bottle arrives, a sensor opens the gate and triggers the cap to be fed to the bottle. A chuck then descends and rotates to screw the cap onto the bottle until a magnetic clutch reaches the set torque and slips. At this point, the chuck system disengages. A separate, variable-speed spindle drive enables the chucks to rotate independently from the rotational speed of the capper turret. This allows for fine adjustment of the cap-application speed to best fit the thread profile of the cap and bottle.

Both the filler bowl and the capper turret can be raised and lowered electrically to facilitate changing bottle sizes. Further aiding bottle changes are color-coded and engraved bottle-handling parts that can be changed without requiring tools. The filler/capper unit incorporates Allen-Bradley variable-frequency drives, an SLC 5/04 PLC and a pedestal-mounted PanelView 600 operator station from Rockwell Automation.

From the capper, bottles are conveyed to a Trine Model 4500 hot-glue labeler from Accraply-Trine, Inc. (www.trinelabeling.com). Bottles are diverted onto the labeler conveyor, and a feedscrew delivers them into a starwheel that meters them into the label application area.

A roll of labels is mounted horizontally at the discharge end of the machine, and labels are pulled through the labeler by a feed roller mounted just before the label-cutting station.

As the labels enter the labeler, they pass through a label-web guiding system from Fife Corp. (www.fife.com) that consists of a sensor, a controller and a series of vertical rollers that pivot to keep the labels perfectly level as they travel through the labeler.

Labels exiting the web guide then pass an electronic registration system that detects the registration mark on each label and adjusts the speed of the feed roller so the labels are perfectly positioned as they enter the cutting system. This consists of a rotating drum with an attached knife that contacts a stationary knife to cut the label from the roll.

The label then transfers onto a rotating vacuum drum that transports it past a hot-glue applicator. Earth20 is using a wraparound label, so the unit applies glue to the leading and trailing edges of each label. Stationary pads are installed on the vacuum drum that lift the sections of the labels where glue should be applied, so they contact the glue applicator, while the remainder of the label is held tightly against the drum, so it does not contact the applicator.

The label and the bottle then come together, and the label is transferred through the rotation of the bottle until the entire label has been placed on the bottle, and the label seam is made.

The six-color polypropylene labels for the Earth20 products are supplied by Superior Tape & Label (www.superlabel.com) and Relm West Labels, Inc. (www.relmwest.com). They are flexographically printed on the reverse side of the web to prevent scuffing and to accentuate the graphics.

Bottles leaving the labeler pass in front of a SmartLase CO2-style laser coder from Markem Corp. (www.markem.com) that applies a date code to the shoulder of the bottles.

The bottles are then conveyed out of the filling room and travel to a bulk conveyor that transports them around a u-curve and delivers them to the Arpac wrapper and shrink tunnel described previously. As the bundle leaves the shrink tunnel, a Marsh Patrion ink-jet printer from Videojet Technologies, Inc. (www.videojet.com) imprints a product code on the film. Twenty-four- pack bundles are then conveyed to a hand-palletizing station. Two-, four-, six-, eight- and 12-pack bundles are either hand-palletized or are pushed to the far side of the conveyor by a pusher mechanism from Container Handling Systems Corp. (www.containerhandlingsystems.com). The conveyor then transports them to a machine that assembles them into groups containing 24 bottles and wraps them in plastic film.

Arpac designed the entire bottle-conveying system after the filling room and also made other significant line modifications and improvements as part of the entire integrated system.

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