HANDLING SYSTEM FOR LIGHTWEIGHT CONTAINERS INCLUDING BALLAST DISPENSER

Abstract: Lightweight containers such as polyethylene terephthalate (PET) beverage bottles (20) are rendered stable for conveyance on a horizontal conveyor (40) by temporary addition of water ballast (44). The ballast (44) is drained during washing/rinsing steps and thus does not add to the permanent weight of the bottle. Ballast in the amount of about 2 to 10 % of the bottle volume is sufficient to enable increased production line speed with fewer bottle jams due to the lightweight bottles falling over. The ballast may be added in an amount of 50 to 150 % of the empty container weight for a typical container, thus filling the bottle only 0.5 to 1.5 inches at the bottom. The bottles are arranged upright, for example at a depalletizer (30), and loaded with ballast from a reservoir or pressurized supply of water. The bottles can be loaded in a group and a plurality of valves (168) having valve bodies (166) on a movable common support open simultaneously. The ballast is removed at the bottle rinsing station, which inverts the bottles to drain the ballast as well as rinse water.

Description: HANDLING SYSTEM FOR LIGHTWEIGHT CONTAINERS INCLUDING BALLAST DISPENSER Background of the Invention 1. Field of the Invention This invention relates to the field of container handling, fo example in bottling plants, and in particular to an improvement i handling systems for lightweight plastic bottles. A limite quantity of ballast is inserted into the bottles so as to plac temporary additional weight adjacent the bottoms of the bottle during handling prior to filling, thereby lowering the center o gravity of the bottles for stable transport on horizonta conveyors. 2. Prior Art Bottling systems and similar container processing devices us automated handling apparatus to provide as high a throughput rat as possible. The handling apparatus typically carries the bottle in serial order through a number of processing steps such a washing, rinsing, filling and capping. The handling apparatu normally includes various runs of horizontal conveyor sections which move the bottles while supporting them from below. Su automated handling apparatus are effective provided the bottles ca be handled smoothly at the required rate. In a known bottling system, for example, empty bottles ar supplied on pallets wherein levels of bottles are stacked on o another with interleaved panels providing a supporting surface fo the bottles on each level or rank. A depalletizer removes ea topmost level or rank of bottles from the pallets, and places t rank at a receiving platform defining the input section of horizontal conveyor. The receiving platform has a horizont support surface leading to a funnel-like constriction where successive decreases in width along the conveying path force t bottles into single file, from which the bottles proceed serial one after another through continuously operating processing steps. The funnel-like section serves to accumulate the bottles because each rank from the depalletizer requires a certain time to be converted from an X-Y array of bottles to a single file. Theoretically, the next rank is supplied just as the previous rank is exhausted. The bottles in the single file are then carried by a conveyor typically having one or more endless loops of conveyor belt, horizontally attached link plates, rollers or the like, which define a moving horizontal platform for supporting the bottles while advancing the bottles to the next processing station. Each bottle simply rests on a horizontal surface which is moved to advance the bottle. The bottles move through stations typically including the depalletizer and funnel arrangement as described, a bottle washer or rinser where the bottles are inverted and a fluid is sprayed in from below and then allowed to drain, and a filler and capper. The filler and capper has a carousel with a plurality of filling positions at which an empty bottle can be received, filled and finally capped, while moving along a conveying path. The bottling system preferably runs continuously. For maximum production it is necessary to avoid both stoppages of the line and gaps in the single file progression of bottles. In addition to the lost production caused by gaps in the line, the bottles to some extent support one another upright as they are moved along the conveyor. Where gaps occur, the bottles leading and trailing the gap lack support from adjacent bottles and more easily fall over. When a bottle falls over, the entire line may become jammed. It is difficult to avoid gaps in the continuous progression of bottles along the horizontal conveyor. A gap occurs at least between batches of bottles when starting and stopping any of the processing stations along the bottle path. Depalletizing is inherently a batch process. Various occurrences along the path of the bottles may result in gaps opening up. Typically, one or more workers are required to watch the line and to clear jams. The general nature of bottling plants is well known and well developed. In recent years, however, plastic containers have come into use. The plastic containers are thin but durable, and light * in weight, which qualities have obvious advantages in reduction of shipping weight, ability to use lighter production equipment and * the like. However, the bottles are so lightweight as to be 5 unstable when carried on a horizontal conveyor. In order to avoid jamming of bottling lines when running plastic bottles, the lines are run substantially more slowly than a comparable line running glass bottles, which are heavier and therefore more stable. Even at slower rates of throughput, the plastic bottles tend to fall 10 over much more frequently than do glass bottles, and more workers are needed to correct recurrent jamming and resume proper operation of the line. Plastic bottles are used for a wide variety of products. A typical lightweight plastic bottle is made of polyethylene 15 terephthalate (PET) . Standard bottle capacities, for example for beverage containers or bottled water are 12 ounce, 16 ounce, 20 ounce, 1 liter, 1.5 liter, 2 liter and 3 liter. Of course other sizes are also possible and in standard use for various products. Plastic is also a popular material for other forms of containers 20 which might be described as cans or jars rather than bottles. In recent years, technical advances have reduced the weight of plastic containers such as bottles by as much as 30%. Whereas a glass bottle in a small beverage container size might weigh 6 ounces, a plastic bottle of comparable volume weighs a fraction of 25 an ounce. The bottles are often taller than they are wide and when unsupported are easily knocked over, for example by uneven conveyor passages, impacts, or even by a breeze in the bottling plant. Plastic bottles can be made in one integral piece of PET, or can be assembled from two or more pieces. A standard two piece * 30 variety includes an attached base cup which is bonded to the bottom of the bottle, tending to protect the base and incidentally adding * to the bottle weight at the bottom. Plastic bottles in one integral piece also can be made with an excess of plastic at the bottom. A "petaloid" form of bottle has a scalloped bottom with 35 radially oriented folds which increase the rigidity of the bottle at the bottom and also provide additional weight at the bottom due to the additional material at the fold. Another form of bottle is the "champagne" type, which has an inward dome in the bottom. A form of bottle construction that has a larger proportion of material at the bottom is inherently more stable than a bottle which is more top heavy. Of course a bottle with a shorter and wider form will also be more stable than a bottle which is taller and narrower. The present invention is applicable to any of these forms; however, a relatively tall and narrow bottle with a minimum of material at the base of course can achieve the greatest improvement in stability. In bottles having a reinforcing bottom cup, the cup is generally made of less expensive plastic than PET. The cup is normally opaque rather than clear. The added bottom weight is helpful for stability, but on the other hand the reinforcing cup conceals the contents at the bottom, requires additional manufacturing steps, and renders the bottle unacceptable for recycling into new PET material. The bottom cup is also undesirable in that it adds to the total weight of the bottle after the bottle is full and stability is no longer a problem. Recycling operations typically cut off and discard the entire bottom of cupped bottles in order to recycle the PET top. It is possible to deal with problems encountered due to the instability of plastic bottles by varying the nature of the conveyor. According to one method, plastic bottles are not carried on horizontal support surfaces, but rather are moved along supporting structures having rails or flanges that face inwardly to engage the neck of the bottle. The bottles are provided with a circumferential bead or flange at the neck, that rests on the conveyor rails to support the bottle. In an example known as an Airveyor, the bottles are supported entirely by such rails, and blasts of air are used to propel the bottles along the conveyor path. While such systems are useful, it would be desirable to provide a substantially jam-proof arrangement that does not require added bottle material, processing requirements and/or conveyor structure. As noted above, instability is a critical problem with lightweight plastic containers. Instability is less of a problem with glass containers as they are heavier to begin with. However, even a glass bottle may have a particularly high ratio of height to diameter, making it unstable in the same manner as a plastic bottle. In connection with glass bottles, U.S. Patent 2,516,998 - Kimball et al discloses adding water to containers along a conveyor. According to Kimball, reusable (i.e., glass) bottles enter a delabeling apparatus along a conveyor leading to a tank containing a liquid in which the bottles are to be immersed for the purpose of soaking the labels off the bottle sidewalls. The bottles are led into the tank via an inclined run of the conveyor and would float in the tank unless steps were taken to force the bottles to sink. A liquid spraying device is provided upstream of the tank to fill the bottles sufficiently that they sink when carried into the soaking liquid by the inclined conveyor. The bottles are immersed until their neck labels are below the level of liquid in the tank. According to the present invention the bottles are not filled to where they would sink. Instead, bottles are stabilized by preliminarily placing a limited quantity of ballast in the bottom of the bottles. The ballast can be added in an amount comparable to the empty weight of the bottle, the ballast residing immediately adjacent the bottom. This lowers the center of gravity of the bottles as compared to empty bottles (and also as compared to substantially filled bottles) such that the stabilized bottles will not easily fall over when carried on a conveyor which supports the containers from below. Kimball does not lower the center of gravity of the bottles or otherwise address stability. Kimball simply increases the overall weight of the bottles to exceed the weight of the soaking liquid which the bottles displace when disposed in the tank. The bottles are glass, which is heavier than water (specific gravit approximately 2.3); however, in view of the thin walled hollo nature of the bottles it is necessary to substantially fill the with water to make them heavy enough to sink as required to thei necks. Assuming that a bottle is filled completely with liquid, or at least filled to a point substantially above the center of gravity as empty, the resulting (filled) center of gravity is approximately at the same height as the center of gravity of the bottle when empty. Additionally, substantial filling requires substantial time, as does emptying the container afterwards. A typical bottling plant includes at least a means for rinsing the containers. U.S. Patent 2,915,773 - Whelan discloses dispensing a spray from an upwardly oriented nozzle into a downwardly oriented bottle, for rinsing. The spray of course drains away. U.S. Patent 3,079,936 - Hockett et al discloses complete immersion of bottles, followed by inverted rinsing. Hockett requires individual pockets for supporting each bottle, and therefore avoids problems with the bottles falling over. U.S. Patent 3,159,164 - McBrady dispenses cleaning fluid upwardly into the containers when carried around a carousel which inverts the containers. As in Whelan, the fluid drains away. As in Hockett, the containers are individually supported, thus avoiding a need for stability, as in horizontally supported bottles. U.S. Patent 3,270,783 - Hughes discloses a bottle filling apparatus. The bottles are of course filled substantially completely with the contents to be stored therein. Whereas the bottles are filled, the center of gravity is not lowered as occurs when a limited quantity of ballast is placed in a container to improve stability. U.S. Patent 3,545,024 - Randrup discloses cleaning the external surfaces of bottles. According to the disclosure, gross accumulations of the cleaning liquid are to be removed. The accumulations which are described are on the outside surface of the bottles. U.S. Patent 3,674,060 - Ruekberg limits the level to which a container is filled by a filling machine. Nevertheless, the container is filled substantially completely and no means are suggested for improving stability by limited filling with ballast during handling of the empty containers. In U.S. Patent 3,985,096 - Guimbretiere, fluids are applied to medical slides. The slides are supported individually by suction cups, as needed to incline the slides for removal of excess fluid which remains after application of the fluid. U.S. Patent 4,061,152 - Babunovic employs spray heads on a manifold in a bottle washing apparatus. The apparatus includes nozzles which direct fluid over the containers. However, the containers are supported in a fixed rank by the apparatus and moved together with the support through a circuitous path including inversion of the containers. There is no means to improve stability of empty containers on a conveyor by preliminary addition of a limited quantity of ballast. U.S. Patent 4,325,775 - Moeller includes a drenching station with a downwardly directed fluid nozzle 26. The drenching station is intended to apply water externally for softening labels on the outer surface. Whereas the drenching nozzle is above the container in Fig. 2, some of the drenching liquid might be expected to fall into the container. The disclosed drenching uses a "high volume" of fluid (Column 2, line 33), thereby presumably filling the container. The container is fully supported by the delabelin structures. U.S. Patent 4,683,009 - Shriver concerns spraying a sealin compound on the surfaces of plastic containers. The compound is applied externally. A jet of hot air is applied downwardly. U.S. Patent 4,715,920 - Ruppman et al also handles plasti bottles. The bottles are supported by their necks, eithe individually or on a neck rail. A supplemental polyethylene cu is attached to the bottom of each bottle, rendering the bottle bottom heavy. Ruppman is an example of the processing step required to place protective cups on the bottoms of bottles. U.S. Patent 4,779,634 - Gutierrez et al applies rinse wate to containers already filled with a food product. The container are inverted to drain the surface water from the food while th food is retained by a perforated panel. In order to enable an increase in production speed i processes such as bottling plants which require the handling of plastic bottles, it would be desirable to render the bottles more stable without increasing the cost and complexity of bottle processing and without attaching additional material to the bottles. It would also be desirable to provide a means to render the bottle stable when needed, i.e., when the bottle is empty and being conveyed, which does not increase the weight of the bottle thereafter. These objectives should be met without substantially interfering with the handling of the bottles during washing or rinsing, filling and/or capping. Summa y of the Invention It is an object of the invention to facilitate handling of lightweight containers, especially plastic bottles, by temporarily increasing the weight of the bottles during handling while empty, using an easily placed and easily removed ballast. It is another object of the invention to provide an improvement for bottle handling apparatus in the form of a particular method and apparatus for adding ballast to bottles. It is a further object of the invention to add weight to bottles in a manner that does not add to the permanent weight, use of materials or handling problems associated with bottles. It is a yet another object of the invention to provide an amount of temporary water ballast in an empty container sufficient to lower the center of gravity of the bottle below the center of gravity of an empty bottle, by filling the bottle for a limited height adjacent the bottom. These and other objects are accomplished by a method for handling lightweight open containers, including arranging the empty containers in an upright orientation, dispensing a quantity of ballast into the containers, and moving the containers along a conveyor, the ballast tending to keep the containers stable on the conveyor. The ballast is preferably water and can be removed after the bottles have been moved on the conveyor, for example by inverting the containers to drain the ballast by gravity. In a bottling plant the typical rinsing apparatus can be used to empty the bottles of ballast in this manner. This arrangement works quite well with polyethylene terephthalate (PET) bottles. A limited quantity of water ballast, preferably 2% to 10% of the container volume (normally about 50% to 150% of the empty container weight) , precludes many of the problems of bottle fallover and bottle jamming that are associated with very lightweight bottles. This amount of ballast is minimal, for example one or two ounces in typical beverage containers or containers for bottled water, and can be dispensed into the containers very quickly while th containers are being loaded onto a conveyor or processed along the conveyor. The water ballast occupies, for example, about 0.5 to 1.0 inch of the container height (e.g., 6 to 12 inches) , or between 4% and 10% of the container height. This limited amount can be inserted quickly and also can be drained quickly when no longer needed, e.g., during the bottle washing, rinsing and draining steps. Preferably, the ballast is added at an early point in processing empty containers, for example during or immediately after depalletizing the bottles. The ballast can be added at this point by an array of valves associated with a ballast reservoir under which the bottles are passed while arranged in a corresponding array in an upright orientation. Once the ballast is added the bottles can be handled at high speeds and through various obstructions. According to the invention the relatively low typical speed of a bottling system for lightweight containers (e.g. , several hundred per minute) can be increased substantially (e.g., to 2500 per minute or more). The valves communicating with the reservoir or other source of ballast can by arranged in an X-Y array or in a line. According to a preferred embodiment the valves are defined by a plurality of openings in a reservoir wall controllably plugged by valve bodies attached to a common support. The valves are opened simultaneously by displacing the common support. Brief Description of the Drawings The invention is described herein with reference to a number of exemplary embodiments but is capable of embodiment in other specific forms in accordance with the invention as defined in the appended claims. In the drawings, Fig. 1 is a perspective view of an initial section of a container handling process according to the invention, with a depalletizer leading to a horizontal conveyor; Fig. 2 is a perspective view from an opposite direction, with the depalletizer shown generally and the ballast reservoir broken away; Fig. 3 is an elevation view thereof; Fig. 4 is an elevation view of a further section in the handling process, leading to a container rinser; Fig. 5 is a section view showing a preferred ballast dispenser according to the invention; Fig. 6 is a partial elevation view of the ballast dispenser; and, Fig. 7 is a perspective view of a ballast dispenser according to an alternative embodiment. Detailed Description of the Preferred Embodiments The invention provides a method for handling lightweight open containers, particularly plastic containers such as beverage bottles and water bottles, but also including other forms of empty containers and the like which are subject to falling over when carried on a conveyor. The containers are arranged in an upright orientation, a quantity of ballast is dispensed into the containers to lower their center of gravity, and thereafter while moving along a conveyor, the ballast keeps the containers stable. After serving its stabilizing function, the ballast is removed, preferably simply by inverting the containers at a container rinser. Fig. 1 illustrates the initial section of a container processing plant, in particular a bottling plant as typically used in bottling soft drinks, beverages or bottled water. Such bottles are typically employed in standard sizes with volumes of 12, 16 and 20 fluid ounces and in 1, 1.5, 2 and 3 liters. The containers can be polyethylene terephthalate (PET) bottles, which are quite light in weight. The containers in general pass through stages of depalletizing, ballast loading, rinsing (which includes inverting the containers and thereby unloading the ballast) , filling and capping. The depalletizer 30 receives a pallet 22 of bottles 20 or the like. The bottles 20 are supplied in a plurality of horizontal levels or ranks 26. For example, each rank may have 300 or more bottles, standing upright on their bottoms on a divider panel 24. The depalletizer 30 includes a vertical indexing drive means 34 operable to raise the pallet 22 in increments equal to the vertical height of a rank 26 and its base panel 24. After each index the uppermost rank is disposed at the same level as a conveyor 40. A sweep bar or housing 32 encloses around the periphery of the uppermost rank, and when the uppermost rank is in position the sweep bar 32 advances toward and over conveyor 40 to move the peripherally enclosed bottles onto the conveyor 40. Conveyor 40 can be arranged to index synchronously with advance of the sweep bar or can be continuously moving. Conveyor 40 in the embodiment shown defines an endless loop, however, it can be made up in sections of smaller endless loops. The conveyor can have a continuous flexible mesh or the like, or can be made of linked plates. At least the section in the area of the ballast loading apparatus 160 is foraminous or arranged with gaps, such that spillage of the ballast can fall through to a receptacle therefor. The ballast can be loaded by passing the upright bottles through a continuous downward spray. However, this is somewhat wasteful of water and/or pumping capacity. Each rank of bottles at the depalletizing stage in processing is arranged in an orderly fashion, with the bottles disposed in a regular X-Y array. The ballast loader 160 accordingly preferably has dispensing orifices for each position in the array, operated briefly when the bottles are aligned with the dispensing orifices. When the rank 26 advances to a point in registry with the ballast loader, which can be timed or sensed, the ballast loader is activated and a quantity of ballast, preferably clean water, is dispensed into each of the bottles in the array. The added ballast renders the bottles substantially more bottom heavy and stable, reducing the tendency of the bottles to fall over. Without the added ballast the bottles would often fall over, particularly at the leading and trailing lines in the rank, where no neighboring bottle is disposed to help keep the outermost bottles upright. Without ballast, it is also sometimes the case that an inwardly falling bottle will cause a whole line of bottles to fall in a domino effect. It is also possible to add ballast to a limited number of bottles in a rank, although this is not preferred. For example, ballast could be added to the peripheral bottles only, thus defining a stable wall of bottles enclosing the unstable internal bottles. Ballast could also be added to every other bottle, etc. However, since the relative positions of the bottles is not retained throughout the process, it is preferred that all the bottles be loaded with ballast. Other forms of depalletizers and the like can also be equipped with ballast loading means. For example, in an embodiment (not shown) wherein the containers in a row are transferred from a pallet to a conveyor using gripping mechanisms, the gripping mechanism can be provided with a nozzle that injects the ballast during the transfer. Alternatively, the ballast loader can be placed at another point in the bottle processing sequence. In the exemplary embodiment shown, the bottles moving in a stable rank along conveyor 40 are converted into a row arrangement to be carried further through the process along conveyor 60. There are a number of possibilities for converting an X-Y array into ' a row. In the embodiment illustrated in Fig. 1, for example, the lateral sidewalls enclosing conveyor 40 are narrowed incrementally, forcing the bottles 20 to merge into a row for receipt on single file conveyor 60. This structure is an example of an obstruction along the conveyor path that could easily cause bottles to fall over, particularly if the conveyor is moving at a substantial speed. Various potential obstructions may be defined along a typical conveying path. The ballast in the bottles renders the bottles stable and allows them to be advanced through such obstructions at a substantial speed without undue fallovers. Fig. 2 illustrates an embodiment including one or more gates 36 for retaining the rank in position at the dispensing station. The gates 36 can by pivotable vertically or horizontally, for example being mounted on supports 42 for the ballast reservoir 44. An air cylinder (not shown) can advance and retract the gates for each ballast loading cycle. As shown in Fig. 3, the ballast reservoir 44 can be vertically adjustable, for example via handwheel 56. This enables the orifices in the reservoir to be placed immediately over the open tops of the bottles. The handwheel can drive a rack and pinion positioning mechanism or a winch for lifting and lowering the reservoir. Suitable locking means fix the reservoir at the desired position. Conveyor 60 (see Fig. 1) advances the bottles, preferably in single file, to a rinsing apparatus 110. The incoming conveyor 40 can be positioned at the height of the highest rank of bottles in a pallet, and the conveyor path downstream along the bottle path can include a decrease in elevation via inclined conveyor section 70. This enables mounting of the rinsing apparatus and filler/capper at floor level. A suitable inclined conveyor is available under the tradename Lowerlator. The rinsing apparatus 110 as shown in Fig. 4 inverts the bottles initially, thereby draining the ballast via gravity, sprays a rinse solution (preferably clean water) into each bottle, and after a draining time replaces the bottle upright. During passage from the ballast loading apparatus 160 to the rinsing apparatus 110, the bottles are stable, and this is achieved without adding to the material or expense of the bottles. The ballast system has a minimal effect on the bottling process as a whole. Inasmuch as the bottles are to be rinsed in any case, the ballast does not require additional steps to remove or further clean the bottle, in addition to that already undertaken in the known rinser. Overspray and drained rinse solution or ballast is preferably recovered. In the area of ballast loader 160 a catch basin 46 defining a wide channel under conveyor 40 receives overspray and the like from the ballast loader. The channel can extend continuously along the length of the inclined section 70 to the rinsing apparatus to catch ballast dripping from the outside of the bottles. Alternatively, the catch basin 46 can be connected by suitable conduits to the ballast storage reservoir 44 with a pump provided for moving the collected ballast fluid or material back to the ballast dispenser. In the embodiment shown in Figs. 3 and 4, the catch basin 46 is arranged to drain into the same reservoir 122 used by the rinser 110. A pump 48 moves the ballast material back to the reservoir 44 and also provides pressurized water for rinser heads 116. Pump 48 or a valve along the path from pump 48 to the reservoir 44 can be operable under control of a level or pressure sensor at reservoir 44 (not shown) , for maintaining a predetermined level or pressure of ballast fluid in the reservoir. The rinser 110 also includes a catch basin 118 draining into a tank 122, collecting overspray and drainage, and recycling the solution. The preferred solution for both ballast and rinsing is clean water, and suitable filtering and/or water purification apparatus can be associated with the water handling systems for both ballast and rinsing such that the water remains clean for at least a number of ballast or rinsing cycles. Of course it is also possible to use fresh water for ballast and/or rinsing and simply to discard the water after use. The rinser 110 receives bottles from the inclined conveyor section 70 and inverts the bottles via an inverting guideway 112 leading to a section of conveyor at which the bottles are moved while inverted. The rinse spray and drainage collection means are disposed at this section. A further inverting guideway 114 returns the bottles to the upright orientation for filling and capping at an apparatus (not shown) placed downstream of the rinser along the bottle path, in a conventional manner. Inverting guideways and filler/capper apparatus are known in the art per se. However, the operational speed of conveyors, rinsers and filler/capper apparatus has been limited as applied to lightweight containers due to problems with handling the containers in a manner that is not unduly subject to jamming. The preferred containers (e.g., bottles) essentially comprise polyethylene terephthalate, which is lightweight and durable, but is quite unstable in handling of empty containers due to the low weight of the material and the relatively top heavy arrangement of thin walled plastic containers in the sizes and shapes which have become standard for beverage bottles, bottled water containers and the like. These sizes and shapes are desirable because they are convenient for pouring and fit into standard storage shelves in refrigerators and the like. The weights and dimensions of a number of standard sizes are illustrated in Table 1, including containers with attached protective bottom cups and those which are one integral material. The containers vary in ratio of height to diameter, but generally are two to four times as tall as they are wide. TABLE 1 TYPE - WGT - BOTTLE/CUP - DIA - HGT - RATIO D/H 12 oz. water 24g (one piece) 5.6cm 18.1cm 3.3 16 oz. beverage 27-29 (one piece) 6.7 16.8 2.5 1 liter beverage 42 (one piece) 7.6 27.6 3.6 1 liter beverage 48 39g/9g 7.6 27.6 3.6 1.5 liter water 42-47 (one piece) 8.6 30.2 3.5 2 liter beverage 29.9 2.9 2 liter beverage 29.9 2.9 3 liter beverage 32.7 2.7 3 liter beverage 32.7 2.7 The preferred amount of ballast to be dispensed into the containers is shown in Table 2, together with a comparison of the volume and height of the preferred amount of ballast to the volume and height of the container. The preferred amounts of ballast are small compared to the container volume, and thus can be loaded into the container quickly, and drained quickly after use. The noted amounts are preferred and it should be understood that the specific ratios and volumes can be changed as appropriate in view of variations in the container height to width ratio, the relative need for stability in view of other aspects of the handling apparatus, etc. Stabilitywill always improve providedthe ballast is added in a sufficient amount to lower the center of gravity to a point lower than the center of gravity of the empty container. TABLE 2 As presently preferred, in connection with containers of the standard sizes noted, with height to width ratios of about 2:1 to 4:1, ballast is added in an amount sufficient to fill the bottle to about 4 to 10% of the container height, which is equivalent to a relative volume of ballast to total container volume of about 2 to 10%. Inasmuch as the empty containers are quite light, this limited amount of added ballast ranges from about 50% to 150% of the container empty weight. It is appropriate for containers with a relatively higher ratio of height to width to use relatively more ballast, and for containers with a lower ratio to use less ballast. When considering the two piece containers listed in Table 2 (i.e., containers including end cups), Table 3 compares the supplemental bottom weight (ballast plus end cup) to the weight of the overall container. Whereas the total weight added to the container at the bottom (temporarily by the ballast and permanently by the end cup) is substantial as compared to the container weight, and preferably exceeds the container weight, it will be appreciated that the effect is to move the center of gravity of the container much closer to the bottom of the bottle than the center of gravity of the bottle when empty. According to the invention as applied to containers without end cups, the added stability of a container with an end cup is obtained (due to the weight of the ballast) . However the ballast is emptied after handling, and accordingly the drawbacks of an end cup, including the need for additional material, added weight, etc., are avoided. TABLE 3 TWO PIECE TYPE TOTAL WGT. BALLAST PLUS ENDCUP %OF TOTAL 1 liter 48g 68g 142% 2 liter 69 79 114 3 liter 96 83 86 Water ballast dispensed into the bottles in sufficient amounts to place about 0.4 to 2.0 inches, and preferably 0.5 to 1.0 inch of ballast in the bottom, effectively places a stabilizing weight on the order of the empty container weight immediately adjacent the bottom of the container. Whereas an empty container has a center of gravity that is near the midpoint of its height (or somewhat lower for bottles with end cups) , the ballast temporarily moves the center of gravity to a point between the original center of gravity (e.g., the height midpoint) and the bottom of the bottle. The ballast is preferably filled to a point below the center of gravit of the empty container. However, the amount of ballast can be increased to a point above the center of gravity of the empt container provided the net effect is to move the center of gravit to a point below that of the empty container. More particularly, the center of gravity of the added ballast apart from the bottl must be located lower than the center of gravity of the bottle t achieve improved stability. A fluid ounce of water ballast weighs about 29.5 grams, and i containers of a volume comparable to the standard containers show in Tables 1-3, only one or a few ounces of water provide substantial stabilizing weight as compared to the container weight. Therefore, a very limited quantity of water is normally sufficien to enable substantially increased production speeds, approachin the speeds at which glass bottles can be handled. Wherea empty plastic bottles can be handled on horizontal suppor conveyors at nominal rates of several hundred per minute, the sam conveyors can handle container including water ballast at up t 2,500 bottles per minute without undue jamming. The particula speeds obtainable will vary with the particular bottle shape, conveyor arrangement and other factors. Insofar as any shape o bottle is apt to fall over due to handling, ballast according t the invention will improve stability and enable handling at highe speeds. The ballast can be dispensed into the bottles according to number of specific techniques and apparatus. Preferably th ballast is dispensed into a number of the bottles simultaneously, however it is also possible to dispense the ballast by sensing th position of individual bottles and operating a valve or the like t dispense the ballast into each bottle as it passes the valve. Another possibility is to operate the ballast dispense continuously, dispensing spray generally and at a flow rate whic is sufficient to accumulate the required amount of ballast in eac bottle over to the time in which the bottles pass the continuously operating dispenser. In that case the ballast can be dispensed from one or more wide pattern spray heads directed downwardly over the path of the bottles along conveyor 40. Preferably the ballast is dispensed into a group of the containers from a rank 26 from a pallet as shown in Figs. 1, 3, 5 and 6, before forming the containers into a row. The dispenser can simultaneously load ballast in an X-Y array of the containers, for example an entire rank 26. Alternatively, the dispenser can simultaneously load a lateral line of the containers in a rank as shown in Fig. 7. For dispensing ballast into a line or rank, a plurality of orifices in the lower wall of a reservoir or pressurized ballast storage vessel can be provided. Means can be provided for opening a plurality of valves as the bottles in a rank pass the valves. The bottles in the pallet are placed directly against one another and thus define a regular array. The depalletizer sweep places the bottles on the conveyor 40 in a predictable array, and the orifices or valves in the dispenser 160 are aligned to the array, as shown in Figs. 5 and 6. Apart from the depalletizer a gate 36 can be placed at the end of the dispenser 160 along the path of conveyor 40 such that the bottles queue against the gate and assume a regular array, as shown in Fig. 2. This array can be a linear array (Fig. 7) or a matrix array (Fig. 1) . The bottles can be stopped for ballast loading or allowed to advance continuously. For retaining alignment of the ballast orifices and moving bottles, an indexing or tracking drive (not shown) can be associated with the dispenser 160 such that the valves or orifices dispensing the ballast will track moving bottles on the conveyor 40, to direct the ballast into the open tops of the bottles for a sufficient time to load the bottles with the required amount of ballast. According to a preferred embodiment of the dispenser as shown in Figs. 5 and 6, valves in the required array are defined by a plurality of openings or valve seats 168 in the bottom wall of the reservoir. The openings or valve seats 168 are controllably plugged by valve bodies 166 attached to a common support 164. The common support is displaced upwardly to simultaneously open the valves by lifting all the valve bodies 166 relative to the seats 168 at one time. A cam drive, air cylinder, electromagnetic (solenoid) drive or the like (not shown) can lift the common support 164, which is preferably slidably disposed via guide shafts 174 on support blocks 172 fixed on the inner wall of the reservoir. It is also possible to arrange the valves in reverse order, i.e., with a plate (e.g., the bottom wall of the reservoir) defining a plurality of valve seats and a framework supporting the valve bodies for upward and downward displacement relative to the plate from outside the reservoir. An alternative embodiment of the invention is shown in Fig. 4. According to this embodiment, the ballast dispenser includes a pressurized fluid supply rather than a gravity feed supply as in Fig. 3. A pump 184 can be provided to pressurize the supply vessel 182, which has an array of solenoid valves 186 directed toward the containers. The valves 186 can be operated simultaneously, for example when a row or other array of containers abuts a gate (not shown in Fig. 7) along the conveyor. Alternatively, as indicated by the dashed lines in Fig. 7, each valve can be operable individually. A control photoeye is directed downwardly to detect the passing edge of a bottle 20, whereupon the valve is opened for a predetermined time, for example a time determined as a functio of conveyor speed or a preset time controlled by a one shot timer or the like. In addition to the foregoing valved dispensers, it is also possible as noted above to direct a steady spray of ballast water on the area occupied by the bottles. In passing the area, each of the bottles accumulates a quantity of ballast water, which can b pumped in a circuit between a collection reservoir under the bottl zone to the spray heads over the bottles. The invention as disclosed is an improved handling system for empty containers 20, the handling system having a conveyor 40 operable to support and transport the containers when rested thereon, and means 30 for delivering containers to the conveyor in an upright orientation. The ballast dispensing apparatus 160 is operable to dispense a quantity of ballast into containers 20 in the upright orientation, the ballast stabilizing the containers when transported on the conveyor 40. A container inverting apparatus 112, 114 is associated with a destination 110 of the conveyor, and is operable to invert the containers 20 for removing the ballast. The containers are preferably bottles, and the means for delivering the containers is a bottle depalletizer operable to remove a rank 26 of bottles from a pallet and to funnel the rank of bottles into a line. The ballast dispensing apparatus 160 can be disposed adjacent the depalletizer and operable to dispense ballast into a plurality of the bottles prior to being funneled into the line. The container inverting apparatus is associated with a container rinser 110 operable to invert the containers and to rinse the containers via a rinse fluid directed upwardly into the inverted containers. The handling system can be a bottling system and further comprises a filling station. In a preferred embodiment the ballast dispensing apparatus 160 includes a fluid supply 160, 182 with at least one valve 166, 168, 186 directed toward the containers 20 and means 164, 188 for opening the valve when a container is in position to receive the ballast. A plurality of valves 166, 168, 186 can be operable simultaneously to dispense the ballast into a plurality of containers at once. For this purpose, the fluid supply can include a reservoir 162 disposed over the containers and the valves are defined by a plurality of openings 168 in a reservoir wall controllably plugged by valve bodies 166 attached to a common support 164. Means 176, 174, 172 for displacing the common support simultaneously open the valves. The invention having been disclosed, variations will now occur to persons skilled in the art and aware of this disclosure. The foregoing disclosure of preferred embodiments is not meant to be limiting, and reference should be made to the appended claims rather than the foregoing specification to assess the scope of the invention in which exclusive rights are claimed.

Claims: I claim: 1. A method for handling lightweight open containers, comprising the steps of: arranging the containers in an upright orientation; dispensing a limited quantity of ballast into the containers so as to fill a lowermost portion of the containers and thereby lower a center of gravity of the containers as compared to said containers when empty; moving the containers along a conveyor, the ballast tending to keep the containers stable on the conveyor. 2. The method according to claim 1, further comprising inverting the containers to remove the ballast. 3. The method according to claim 1, wherein the ballast is dispensed to at least one of: a volume of about 2 to 10% of an empty volume of the containers; a weight of about 50 to 150% of an empty weight of the containers; a height of about 4 to 10% of a height of the containers; and, a height of about 0.5 to 1.0 inch. 4. The method according to claim 2, wherein the containers are plastic bottles, said conveyor moving the containers to a rinsing apparatus, the containers being inverted at the rinsing apparatus. 5. The method according to claim 3, wherein the containers essentially comprise polyethylene terephthalate and the ballast is water. 6. The method according to claim 1, comprising arranging the containers in an array in said upright orientation and dispensing the ballast into the containers substantially simultaneously fo ~ ~ each of the containers in the array. 7. The method according to claim 6, comprising providing group of the containers from a rank in a pallet of containers, dispensing said ballast into the containers and forming the grou of containers into a row. 8. The method according to claim 6, wherein the ballast i water dispensed from a reservoir by opening a plurality of valves. 9. The method according to claim 8, wherein the valves ar defined by a plurality of openings in a reservoir wall controllabl plugged by valve bodies attached to a common support, and wherei said dispensing includes displacing the common support t simultaneously open the valves. 10. An improved handling system for empty lightweigh containers which are prone to fall over in handling, the handlin system having a conveyor operable to support and transport th containers when rested thereon, and means for delivering th containers to the conveyor in an upright orientation, th improvement comprising: a ballast dispensing apparatus operable to dispense a limite quantity of ballast into the containers when in the uprigh orientation, the ballast dispensing apparatus having a dispensin flow rate and duration sufficient to fill the containers onl adjacent bottoms thereof, the ballast thus lowering a center o gravity of the containers and stabilizing the containers whe transported on the conveyor. 11. The improved handling system according to claim 10 wherein said ballast dispensing apparatus is operable to dispense the limited quantity in an amount corresponding to at least one of: a volume of about 2 to 10% of an empty volume of the containers; a weight of about 50 to 150% of an empty weight of the containers; a height of about 4 to 10% of a height of the containers; and, a height of about 0.5 to 1.0 inch. 12. The improved handling system according to claim 10, further comprising a container inverting apparatus associated with a destination of the conveyor, operable to invert the containers for removing the ballast. 13. The improved handling system according to claim 12, wherein the containers are bottles, the means for delivering the containers being a bottle depalletizer operable to remove a rank of bottles from a pallet and to funnel the rank of bottles into a line, the ballast dispensing apparatus being disposed adjacent the depalletizer and operable to dispense ballast into a plurality of the bottles prior to being funneled into the line. 14. The improved handling system according to claim 12, wherein the container inverting apparatus is associated with a container rinser operable to invert the containers and to rinse the containers via a rinse fluid directed upwardly into the inverted containers. 15. The improved handling system according to claim 14, wherein the handling system is a bottling system and further comprises a filling station. 16. The improved handling system according to claim 11, wherein the ballast dispensing apparatus includes a fluid suppl with at least one valve directed toward the containers and mean for opening the valve when a container is in position to receiv the ballast. 17. The improved handling system according to claim 16, wherein the ballast dispensing apparatus includes a plurality o valves operable to dispense the ballast into a plurality o containers simultaneously. 18. The improved handling system according to claim 17, wherein the fluid supply includes a reservoir disposed over th containers and the valves are defined by a plurality of openings i a reservoir wall controllably plugged by valve bodies attached t a common support, and further comprising means for displacing th common support to simultaneously open the valves. 19. A bottling system, comprising: a depalletizer operable to accept bottles in stacked ranks an to move the bottles in each rank successively to a receivin platform; a guideway associated with the receiving platform and operabl to funnel the rank of bottles into a line; a conveyor having a substantially horizontal movable suppor surface for carrying bottles rested thereon, the conveyor receivin bottles in the line and transporting the bottles to a rinsin apparatus; a ballast dispensing device disposed along a path of th bottles from the depalletizer to the rinsing apparatus, the ballas dispensing device being operable to dispense a limited quantity o weight ballast into each of the bottles so as to fill the bottle adjacent bottoms of the bottles and thereby lower a center o gravity of the bottles; the rinsing apparatus having bottle handling means operable to invert the bottles, whereupon the weight ballast is removed due to gravity; and, a bottle filling and capping apparatus receiving and processing bottles from the rinsing apparatus. 20. The bottling system according to claim 19, wherein the ballast dispensing device includes at least one controllable valve operable to open a flow path of ballast fluid from a fluid source to the bottles. 21. The bottling system according to claim 20, wherein the ballast dispensing device is operable to open the flow path for a duration sufficient to add ballast in an amount corresponding to at least one of: a volume of about 2 to 10% of an empty volume of the containers; a weight of about 50 to 150% of an empty weight of the containers; a height of about 4 to 10% of a height of the containers; and, a height of about 0.5 to l.o inch. 22. The bottling system according to claim 21, wherein the ballast fluid is passed through the valve by at least one of fluid pressure in the fluid source and gravity. 23. The bottling system according to claim 22, comprising a plurality of valves operable to dispense the ballast fluid simultaneously into a plurality of the bottles. 24. The bottling system according to claim 23, wherein the valves define a plurality of valve seats in a wall defining the fluid source and a plurality of valve bodies movable relative to the valve seats, the valve bodies being attached to a commo support and simultaneously movable by displacement of the support and further comprising means for displacing the support upo detection of bottles in position for receiving ballast.

Inventors: PRINGLE FRANK G, PRINGLE, FRANK, G.
Applicants: R & D INNOVATORS INC, R&D INNOVATORS, INC.
Application year: 1992
Main classification: B65B3
IPC codes: B08B9, B65G15, B65G17