Dewatering apparatus for drop marking containers

Abstract: Water and soapy lubricants are removed by an air knife assembly (26) from an area of a container (12) which is to be marked with a code by drop marking equipment (14). Each air knife (26) is positioned at appropriate pitch, roll and yaw angles to remove water only from the area which is to be drop marked, thereby avoiding damage to labels which have been applied, but not yet bonded, to the container (12). The dewatering ensures the proper marking of the product. The angular orientation of each air knife (26) may comprise a yaw angle of about 64° relative to the longitudinal axis of the conveyor, a pitch angle of about 25° from the horizontal, and a roll angle of about 52°.

Description: This invention is concerned with the drop marking of products sold in containers, such as cans and bottles, for instance beer, soft drinks, food stuffs and the like. More specifically, the invention relates to a container marking system for removing liquid (for instance water) from an area of a container that is to be marked, just prior to the marking operation. Dewatering, as the liquid removal step is commonly called in the industry, is necessary to permit typical marking systems, such as ink jet coders, to print information on a bottle or can passing by an ink jet print head during the bottling or canning process. Such marking operations typically place important information on the product, such as date codes, lot information and similar information used to track the product for various purposes. The present invention has particular application to the beverage industry where cans and bottles of chilled drinks, such as beer, soda and the like are placed into cans or bottles by high speed filling equipment. Shortly after the filling operation, capping and labelling operations take place followed by the marking operation to specify a date of manufacture and/or manufacturing codes. Proper coding is an important consideration if it should be necessary to trace the product to a particular assembly line or batch. It is difficult to ensure completely accurate marking of bottles and cans due mainly to the condensation which forms on the outside of the container after it has been filled with the cold beverage. Additional problems can be encountered due to soapy type lubricants used on the product conveyors. If these liquids are not removed from the area of the container to be coded, the ink from the ink jet printer or similar drop marking device, will not adhere satisfactorily to the container. Prior proposals for solving this problem include the use of air manifolds positioned immediately adjacent the ink jet print head. Generally, such manifolds consist of a closed section of pipe connected to an air supply. Small holes are provided along the length of the pipe. Air passes through the holes and is directed at the bottles or cans with the intention of blowing off the undesired liquid. Such prior art designs use more air than necessary, are fairly noisy and do not produce an area as clean and dry as is desired for high reliability marking of the containers. Such prior proposals teach the provision of apparatus, for removing liquid from containers supported for movement past a drop marking station, including means for supplying air at above atmospheric pressure to a manifold to produce air jets which are positioned to blow the liquid off each container before it reaches the drop marking station. Also that a drop marking system, for printing information on containers supported for movement past a marking station, should include a drop marker, and means for supplying air at above atmospheric pressure to a manifold to produce air jets which are positioned to blow the liquid off each container before it reaches the marking station. A further problem with prior art systems is the nature of the air blast which can interfere with label placement and adhesion on the containers being marked. More specifically, front and back labels are usually applied to the containers prior to the drop marking operation and the water based adhesive used on these labels requires a period of time to set. Air blasts, for purposes of dewatering, can dislodge or shift these labels and can blow liquid from other containers onto the area to be drop marked. According to the invention a container marking system is provided which includes a conveyor arranged to move containers past a drop marker for marking each container, and means for supplying air at above atmospheric pressure to a manifold to produce air jets which are positioned to blow the liquid off each container before it reaches the drop marker, characterised in that the air jets are produced by a nozzle which defines a linear array of small openings to create a thin line of high pressure air, positioning means are provided for locating the nozzle upstream of the drop marker, and the positioning means is arranged to direct the thin line of high pressure air at an angular orientation relative to the containers such that any liquid on each container will be removed from the area to be marked by the drop marker. The positioning means is preferably arranged such that the angular orientation of the thin line of high pressure air relative to the containers will minimise the impingement of the high pressure air on areas of the containers that are not to be marked. The positioning means is preferably arranged to permit adjustment of the angular orientation. The angular orientation of the nozzle is preferably between 59° and 69° relative to the longitudinal axis of the conveyor whereby the thin line of high pressure air is directed upstream. The angular orientation of the nozzle is preferably declined from the horizontal between 20° and 30° whereby the thin line of high pressure air is directed downwardly. The angular orientation of the nozzle is preferably rotated between 47° and 57° from a position in which the linear array of small openings would be vertical whereby the top of the array is located upstream of the bottom of the array. In this manner the angular orientation of the nozzle can be positioned at the correct pitch, roll and yaw angles to remove liquid from only the desired area. The line of high pressure air emitted from the nozzle is preferably arranged to shear the liquid downwardly and away from the area subjected to the air blast thereby leaving such area dry and suitable for drop marking. In the case where the container is a can conveyed upside down for drop marking its bottom, a hood is preferably provided to capture the liquid as it is blown off the can. The angular orientation of the nozzle in this case is preferably declined down from the horizontal between 35° and 40°. In a preferred arrangement for the container marking system, a plurality of nozzles are provided. The present invention accordingly provides a container marking system having an improved dewatering arrangement which can effectively remove moisture from the area of a container to be marked while the container is moving on a high speed beverage filling conveyor. The present invention also provides a dewatering system which can be positioned to dewater only the area to be marked and which will avoid interfering with the adhesion of recently applied labels to the container. It will be noted that the present invention teaches the provision of a container marking system that employs at least one air knife precisely directing air at the container to be marked, thereby ensuring that a clean, dry surface is presented to the marking device. The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a plan view of a typical beverage bottling conveyor provided with a drop marking station and illustrating the environment in which the present invention is employed; Figure 2 is an enlarged partial plan view of a bottom left hand portion of Figure 1 illustrating the physical relationship between one form of dewatering apparatus in accordance with the present invention, the drop marking device, and the containers; Figure 3 is a partial side elevation, taken in the direction of arrow 3 in Figure 2, illustrating the relationship between the dewatering apparatus, the marking system, and the product; Figures 4a, 4b and 4c illustrate the angular orientation of the nozzles to maximize performance; Figure 5 is a partial end elevation of a second embodiment of the invention for use with cans which are bottom marked; and Figures 6a and 6b are respectively plan and side elevations of a nozzle in the form of an air knife suitable for use in the present invention. Figure 1 illustrates a typical bottle conveyor suitable for use with the present invention. As is known to those skilled in this art, bottles 12 are carried on the conveyor at high speed in the direction of the arrows past unshown units which fill them with liquid and apply a cap or other sealing device. Next a labeling mechanism applies one or more labels and the bottles then move on to a marking station 10 where the desired date and/or batch coding information is applied by a drop marker in known manner. As indicated schematically, a single back labeling operation occurs upstream of the marking station 10. This operation is carried out by a BACK LABLER which places a label on the back of each bottle. The back labeler is spaced from the marking station 10 by an angle indicated by "DWELL" on the drawing. After passing the marking station 10, the containers 12 continue on the conveyor in known manner towards a final station where they are packed for shipping. As shown in Figure 2, the bottles 12 pass by an ink jet print head 14 positioned at the marking station 10 to print the coding information at a desired position on each bottle. From Figure 3 it will be seen that the print head 14 is usually positioned near the bottom third of the bottle 12, approximately 3/16 of an inch (1 inch = 2.54 cm) from the bottle surface. It is usual and desirable to put the coding information on the backside of the bottle opposite a front label 15 which has been applied at an unshown front labeling station. In order to permit the position of the print head 14 to be adjusted, it is mounted to a print head holder which is generally indicated at 16 and includes a bracket 18 permitting horizontal adjustment both radially and circumferentially of a rail 20 and a bracket 21 permitting vertical adjustment. Utilising bracket 21, the print head 14 can be positioned at a desired height relative to the bottles which are conveyed on respective bottle pads 19 comprising part of the conveyor system. In addition, the radial spacing between the bottles and print head 14 can be controlled by the bracket 18. The print head holder 16 is secured to the conveyor system by clamping the bracket 18, as shown in Figures 2 and 3, to the rail 20 which is part of the labeler system. As seen in Figures 1 to 3, an air knife assembly 26 consists of four air knives for dewatering or otherwise drying the surface of each bottle 12 prior to being marked with coding by the print head 14. The term air knife, as used in this specification, means a linear array of tiny openings connected to a common manifold to which air is supplied to produce a very thin line of high pressure air. The thin line of air can be, as disclosed hereafter, carefully orientated with respect to pitch, roll and yaw angles to strike each bottle accurately as it passes in front of the knife to dewater an area where marking is to occur, whilst still leaving relatively undisturbed other areas of the bottle which, for example, may carry adhesive labels which have not yet set. By utilising a linear array of tiny nozzles to create a thin line of air pressure, and by careful positioning of the knives, water and soapy lubricants can be sheared down and away from the bottle, producing a clean area for the coding operation. Air knives of the type required for use with the present invention are commercially available. For example, such nozzles are manufactured and sold by Lechler Incorporated as nozzle type No. 600.130. Such devices are sold under the trademark WHISPER BLAST and consist of a multichannel flat spray nozzle having a low noise level output. The nozzle utilises a laminar air flow design and is illustrated in Figures 6a and 6b. Typically such nozzles have a linear array of approximately 16 small openings 82 which define tiny nozzles and are formed in a manifold as shown. Each opening 82 is approximately one millimeter in diameter and the openings 82 are spaced approximately 1/8 inch apart (1 inch = 2.54 cm). Air above atmospheric pressure is supplied to the nozzle by coupling a hose to its threaded end 80. From Figures 2 and 3, it will be seen that the air knives 26 are secured to the rail 20 by means of brackets 22 and 24 or any similar fixture. The bracket 22 may be part of the print head holder assembly 16 which, as previously indicated, is connected to the rail 20. If more than two air knives are required a second bracket assembly 24 may be connected directly to rail 20 as shown. The air knives 26 are generally positioned upstream from the print head 14 so as to prepare each bottle prior to its reaching the print head 14. The number of air knives required depend upon the speed of the conveyor line, the number of code letters to be marked, and the size of the area to be dewatered. In most operations two air knives 26 will be employed. A second pair of air knives 26 will typically be used in humid installations or during the summer when increased humidity is encountered. To ensure optimal marking performance, it is necessary to position the air knives at an angular orientation, relative to the containers 12, having an empirically determined critical range of pitch, roll and yaw angles. The correct positioning of the air knives is illustrated in Figures 4a, 4b and 4c. Figure 4a is a plan view of the conveyor line showing the bottle pad 19 having a bottle 12 supported thereon. We have found that the air knives 26 should be yawed, relative to the longitudinal axis 30 of the conveyor pad 19, at an angle of 64 degrees plus or minus 5 degrees. Thus it will be understood that the air knives 26 point upstream of the position at which they are located, and the air emitted therefrom strikes each bottle prior to its passing the air knives 26. Figure 4c illustrates the critical pitch angle. In this end view, it can be seen that the air knives should be positioned at an angle of declination from the horizontal of 25 degrees plus or minus 5 degrees. Summarising Figures 4a and 4c, it will be understood that the air knives 26 should be yawed to point upstream approximately 64 degrees, and should be pitched downwardly with respect to a horizontal plane by an angle of 25 degrees plus or minus 5 degrees. Figure 4b is a side elevation illustrating that the linear array of openings forming each nozzle 26 should be rolled or rotated from a position in which the openings are vertically aligned by 52 degrees plus or minus 5 degrees. The direction of this rotation would be counterclockwise in Figure 4b, assuming that the bottles are moving toward the viewer. This orientation positions the top of each array upstream of the bottom of that array and ensures that water and lubricants are sheared downwardly on the bottle surface to produce a clean area which can be marked. The net effect of the three angles, illustrated and described in connection with Figures 4a, 4b and 4c, is to position each linear array of openings so that air strikes the upper area of the bottle to be marked and forces the water downwardly. As each bottle 12 moves toward the air knives 26, the increasing air pressure brought to bear continues to push the liquid downwardly and off the bottle. This arrangement prevents air and/or liquid from traveling upwardly into a region which may have been utilised for a rear label. The water and/or the air, should they reach the label area, could dislodge the label if the adhesive used to secure it has not yet set. Because of the superior ability of the dewatering mechanism disclosed herein, highly reliable marking can be achieved. Figure 5 illustrates a second embodiment of the invention suitable for use in marking the bottoms of cans. A high speed can conveyor line conveys cans 50 on a belt 52 between supports 54 and 56. The can at the point illustrated in Figure 5 has been filled, sealed and inverted so that its bottom faces upwards. As with the bottles previously discussed herein, because cold liquids have been received in the cans, condensation forms on the outside thereof. Such cans, as known in this art, typically have a concave, part-spherical shaped bottom, illustrated generally at 58 in the drawing. In typical code marking applications, the unshown print head is vertically positioned to mark the part-spherical portion of the can bottom. In order to ensure highly accurate marking, it is necessary to dewater this surface. For that purpose an air knife 60 of the type already described is positioned, as shown, opposite a hood 62 designed to capture the dispersed liquids and to drain them from marking area. The air knife 60 is directed at the part-spherical surface 58 to be marked and has a pitch or declination angle D relative to the horizontal plane, of approximately 37.5° plus or minus 2.5°. The angle D ensures that the air enters the part-spherical recess 58 and traverses substantially its entire surface to blow off condensation. Due to the positioning of the air knife 60, the air carries the liquids, from left to right as seen in Figure 5, into the specially shaped hood structure 62 which consists of a formed piece of metal sheet having an upper extension 64, a vertical extension 66 and a lower extension 68. The hood 62 is designed to capture the dispersed liquids, and to direct them to a drain opening 70 or collection barrel. The hood serves both as a moisture collector and safety shield to protect personnel from the air and liquids during the dewatering process. Preferably an air line 72, for supplying air to the air knife 60, is mounted on the upper extension 64 of the hood 62.

Claims: A container marking system, including a conveyor arranged to move containers past a drop marker for marking each container, and means for supplying air at above atmospheric pressure to a manifold to produce air jets which are positioned to blow the liquid off each container before it reaches the drop marker, characterised in that the air jets are produced by a nozzle (26 or 60) which defines a linear array of small openings (82) to create a thin line of high pressure air, positioning means (16, 18, 20 and 21) are provided for locating the nozzle (26 or 60) upstream of the drop marker (14), and the positioning means (16, 18, 20 and 21) is arranged to direct the thin line of high pressure air at an angular orientation relative to the containers (12 or 50) such that any liquid on each container will be removed from the area to be marked by the drop marker. A container marking system, as in Claim 1, characterised in that the positioning means (16, 18, 20 and 21) is arranged such that the angular orientation of the thin line of high pressure air relative to the containers (120, 150) will minimise the impingement of the high pressure air on areas of the containers that are not to be marked. A container marking system, as in Claim 1 or Claim 2, characterised in that the positioning means (16, 18, 20 and 21) is arranged to permit adjustment of the angular orientation. A container marking system, as in any of Claims 1 to 3, characterised in that the angular orientation of the nozzle (26) is between 59° and 69° relative to the longitudinal axis (30) of the conveyor (19) whereby the thin line of high pressure air is directed upstream. A container marking system, as in any preceding claim, characterised in that the angular orientation of the nozzle (26) is declined from the horizontal between 20° and 30° whereby the thin line of high pressure air is directed downwardly. A container marking system, as in any preceding claim, characterised in that the angular orientation of the nozzle (26) is rotated between 47° and 57° from a position in which the linear array of small openings (82) would be vertical whereby the top of the array (82) is located upstream of the bottom of the array (82). A container marking system, as in any of Claims 1 to 3 and in which the container is a can conveyed upside down for drop marking its bottom, characterised in that a hood (62) is provided to capture the liquid as it is blown off the can. A container marking system, as in Claim 7, characterised in that the angular orientation of the nozzle (60) is declined from the horizontal between 35° and 40°. A container marking system, as in any preceding claim, characterised in that a plurality of the nozzles (26 or 60) are provided.

Inventors: BHATIA CHANDRAKANT R, PETTEREC ROBERT E, BHATIA, CHANDRAKANT R., PETTEREC, ROBERT E.
Applicants: VIDEOJET SYSTEMS INT, VIDEOJET SYSTEMS INTERNATIONAL, INC.
Application year: 1992
Main classification: F26B15
IPC codes: B65C9, B65C3, B41J2, B41F17, F26B21, F26B15