Filler Bowl Operations
The filling unit or filler bowl should be cleaned and sanitized before bottling. To prepare for filling, the beer lines, hoses, and filler should be cooled down using cold water. The water should be blown out before beer is introduced into the filler. The system is then pressurized, and beer is supplied to the filler bowl from the bright beer tank. Some brewers will vent the bowl pressurizing gas prior to the introduction of beer to lower the oxygen contact with the incoming product.
Types of Bottling Machines
The bottles are delivered on a conveyor belt, separated at a predetermined spacing by a separating device, and positioned on a lifting platform under the filling elements by a star wheel infeed device. Basically for the brewer, there are two types of bottling machines available:
These are small long tube machines which are built to fill from one to 8 bottles at a time.
All high-speed machines are rotary machines as shown in Figure 17.4.
Filling Valve Technology
There are two basic types of filling valves, short tube and long tube. Long or short tube refers to the length of the tube associated with the filling head. They work very differently, but both fill under counter pressure (the bottle is counter-pressurized to the same pressure as the filler bowl above the valves containing the carbonated beer) and the product flows by gravity into the bottle. Short tube fillers fill the bottle by running the beer down the sides of the bottle whereas with long tube fillers fill the bottle from the bottom up.
Short Tube Fillers
Short tube fillers have a vent tube about which exhausts the air or gas in the bottle as it fills with beer.
Long Tube Fillers
Long tube fillers use a long fill tube which extends nearly to the bottom of the bottle to fill the bottle from the bottom up.
Bottle Evacuation, Counter-Pressure, and Filling
In pre-evacuation short tube fillers, the bottle is pressed airtight against the filler valve and air is evacuated and pressurized with carbon dioxide, followed by a second evacuation and pressurizing with carbon dioxide is what is called double pre-evacuation. Double pre-evacuation can reduce the air fraction in the bottle to about 1% (12). The beer flows into a virtually pure carbon dioxide atmosphere.
Post Bottle Filler Operations
Once the bottle has been filled and dropped away from the filler valve, it is necessary to clear the head space of oxygen prior to crowning. This is done by creating foam in the bottle neck, with the foam rising and displacing the gas in the head space. There are several methods by which this can be accomplished. The first is to arrange the filling parameters so that the bottle foams as it descends from the filling valve; the second is to add a fobber to the machine.
After the bottle has been cleared of air, the next step is to cap the bottles as soon as possible with the crowner. The caps have a sprayed-on, hot-pressed PVC-based sealing insert or a cold-pressed sealing insert not containing PVC. The caps are conveyed to the crown hopper by means of a magnetic belt or a pneumatic crown feed, or they can be dumped manually directly into the crown hopper. Whatever method is used, the crown hopper should be kept only half full of caps.
When a bottle comes off the filler, it receives a post rinse treatment to wash off the foam, and is then passed through a blower to remove the bulk of the water. If foam were left on the bottle, not only would it be unsightly, glue adhesion could be reduced. This could cause (depending on the glue) slippage and wrinkles on the bottle label. In addition, dried foam can mildew in damp climates if left under the lips of the crown.
Before labeling, it is absolutely essential that the bottles are dry and free of condensation. This is especially important with pressure-sensitive labels that use non-water-soluble glues. Wet glue, which is typically used as an adhesive in glue applications, is much less sensitive to residual water on the bottle.
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