Rotary filling machines are commonly used to fill bottles, such as beer bottles, with liquids. In the conventional filling machine, empty bottles are delivered on a linear conveyor and are then fed by an in-feed star-wheel conveyor to the rotary table or turret of the filling machine. The turret is equipped with bottle supports or platforms which individually lift the bottles against filling valves mounted on the upper portion of the machine. Depending on the capacity of the filling machine the diameter may vary from 2 to 6 meters.
After filling, the bottles are transferred by a star-wheel conveyor to a crowner which applies the cap or crown to the filled bottle. In the crowner the bottles are supported on a rotating table and as the crowner rotates the crown is applied and crimped to the bottle.
In the conventional arrangement, the filled bottles are transferred to the crowner by a star-wheel conveyor operating at high speed, thereby subjecting the bottles to considerable centrifugal force. The centrifugal force causes the beverage level in the neck of the bottle to incline, and depending on the angle of inclination, the beverage can spill from the neck. This problem is particularly evident in the case of short-necked bottles in which the filling point is close to the bottle rim, resulting in an unexpectedly high spillage rate. Because of this problem, the speed of operation of the filler and crowner is limited.
As a further problem, the filled, uncrowned bottle changes direction during its high speed travel on the star-wheel conveyor, and the inclined beer level moves rapidly from one side of the bottle neck to the other, thereby tending to entrap air within the beer. Inclusion of air within the beer can cause decomposition of the beer during storage.
In the conventional filling and crowning arrangement it is customary to mechanically agitate the beer after it is in the bottle to cause the beer to foam into the neck of the bottle to thereby displace the air from the bottle neck prior to capping. The amount of agitation is controlled so that the foam will slightly spill over the top of the bottle. If the beer level is inclined, as occurs when the bottle is subjected to considerable centrifugal force, the mechanical agitation must be regulated so that the low end of the liquid level is foamed to the top of the neck and this results in a substantial over-foaming of the high end of the liquid level. This spillage due to foaming in the conventional arrangement can amount to approximately five barrels per hour for a conventional machine operating at a speed of 1200 bottles per minute.