Abstract:
A device and method for cleaning a glue-application nozzle is provide. An apparatus defines at least one liquid discharge opening for discharging liquid onto the glue-application nozzle. A suctioning device is coupled to the apparatus for suctioning the discharged liquid.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the priority of German Patent Application No. 101 63 744.6,filed Dec. 21, 2001. The disclosure of the foregoing priority application and of each and every U.S. and foreign patent and patent application mentioned herein are incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to a cleaning device and method for one or more glue-application nozzles that spread glue onto materials used in the tobacco processing industry, in particular, packaging materials, cigarette paper and coating paper.  
           [0003]    Glue-application systems, in particular, cold-setting adhesive systems, are sources of contamination in packaging machines and cigarette production machines. The time required for cleaning and correcting the problems caused by glue contamination reduces the capacity of the production lines. Specifically, particles and residues of dispersion adhesives adhering to and around the nozzle-opening regions of the glue-application devices lead to problems, for example, an unclean or uneven adhesive application, plugged nozzles or the splattering of glue particles. Glue-application system manufacturers and machine producers attempt to prevent these problems, for example, with the aid of locking bars or rotating sponge rollers in a water bath. The above-mentioned methods all are subject to wear on the cleaning device and/or the glue application nozzles and require regular maintenance and control, thus leading to correspondingly high expenditures.  
           [0004]    International patent application WO 01/02 101 A1 discloses a cleaning device that uses an atomized jet of a liquid under pressure to clean a glue-application device of residual glue. According to one embodiment disclosed in WO 01/02 101 A1, the liquid, which contains impurities such as the excess glue, is collected and suctioned off to another location.  
           [0005]    The cleaning device disclosed in WO 01/02 101 A1 has a relatively large design and does not automatically clean the glue-application nozzles because the glue-application nozzles cannot be cleaned during operation of the machine. The device disclosed in the aforementioned document is therefore only suitable for cleaning glue-application disks or plates.  
           [0006]    A device for spreading glue onto enveloping material blanks for cigarette packs with a glue-application nozzle is known from German patent document 196 39 260 A1. This reference in particular discloses a cleaning mechanism that acts from the outside upon the glue-application nozzle. The cleaning mechanism is arranged on a catch container and includes a spray nozzle. The cleaning mechanism can also be embodied in the form of a rotating brush.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the invention to provide a device and method for cleaning glue-application nozzles. The device and method preferably cause little wear on the nozzles and require little maintenance. Adhering glue particles on the glue-application device are removed thoroughly and reliably.  
           [0008]    The above and other objects are accomplished according to the invention by the provision of a cleaning device for a glue-application nozzle, for example, a nozzle for spreading glue onto materials in the tobacco processing industry and/or onto packaging materials. The device has at least one liquid discharge opening for subjecting the at least one glue-application nozzle with liquid. The cleaning device furthermore includes a suctioning device for suctioning off contaminated liquid after the at least one glue-application nozzle is subjected with the liquid.  
           [0009]    The cleaning device according to the invention reliably cleans the glue-application nozzles with relatively low wear.  
           [0010]    According to one embodiment of the invention, the liquid is suctioned from a region at or near the at least one glue-application nozzle. The suctioning device is preferably arranged such that liquid contaminated with glue is suctioned off essentially completely from a region near the at least one glue-application nozzle. As a result, other components, for example, a machine in the tobacco processing industry or a packaging machine, are not adversely affected. The cleaning is preferably effected during a break in the glue spreading operation of at least a part of the packaging machine and/or the machine in the tobacco processing industry. As a result of this measure, no additional loss of time resulting from cleaning the glue-application nozzle and/or nozzles is incurred.  
           [0011]    The at least one liquid discharge opening is preferably located at a distance to the at least one glue-application nozzle. A defined cleaning of the glue-application nozzle is possible as a result of the invention.  
           [0012]    According to another embodiment of the invention, the device for subjecting the at least one glue-application nozzle with a liquid is designed such that a liquid jet can be directed toward the at least one glue-application nozzle. A particularly compact cleaning device is realized. The liquid jet is preferably directed toward the front of the glue-application nozzle, especially directly counter or at least partially counter to the glue application device, i.e., counter to the direction in which glue flows through the glue-application nozzle when glue is spread onto the materials. Of course, the offset in timing must preferably be taken into consideration. Accordingly, the above statement is applicable only to the direction of the liquid jet and the glue.  
           [0013]    A high-pressure liquid jet is particularly effective in removing glue residues. The high pressure is generated by a pump that puts the liquid under pressure. A sufficiently strong liquid jet, in particular water, can be generated and focused directly onto the contaminated nozzle area to remove glue residues and other contamination.  
           [0014]    According to another embodiment of the invention, the cleaning device is arranged opposite the at least one glue-application nozzle, in particular below it, such that the glue-application nozzle can remain in the glue application position even during the cleaning operation. A particularly compact cleaning device can be realized by additionally providing a casing that defines or contains the at least one liquid discharge opening along with an opening that can be connected to the suctioning device. In addition, at least a part of the at least one glue-application nozzle is enclosed by the casing in a cleaning position. This design securely prevents liquid from being discharged into the area surrounding the nozzle, thus contaminating and/or wetting other parts of the remaining machinery, e.g. the packaging or processing machine. The arrangement of the suctioning device itself at least a portion of the suctioning device or suctioning opening near the glue-application nozzle prevents liquid from reaching an undesirable area.  
           [0015]    The casing of the cleaning device is preferably movable in the direction of glue-application nozzle, particularly in linear direction to allow for a particularly simple and easy cleaning. Thus, operational breaks of the packaging machine or machines in the tobacco processing industry are not extended as a result of the cleaning of the glue-application nozzle and/or nozzles.  
           [0016]    If the casing is designed such that the at least one glue-application nozzle and casing define a cavity, little or no liquid can escape into the outside. It is therefore preferable if the casing opening that accommodates the glue-application nozzle is designed to fit precisely, so as not to leave a gap between the casing and the glue-application nozzle after the casing is pivoted and/or moved in the direction of the glue-application nozzle into the cleaning position.  
           [0017]    The device for subjecting the at least one glue-application nozzle with liquid preferably comprises at least one nozzle for emitting a defined liquid jet. Alternatively, the device includes a liquid discharge opening.  
           [0018]    The suctioning device preferably comprises a pump unit or an ejector for suctioning the liquid. The ejector in particular refers to a jet pump or a steam jet pump for pumping liquid and/or atomizing liquid. Furthermore, if the casing has a front that points in the direction of at least one glue-application nozzle that is designed for guiding the material onto which glue is spread, no other guide elements are required at this location. Thus, in this embodiment, the casing performs a dual function.  
           [0019]    According to another aspect of the invention, there is provided a method for cleaning a glue-application nozzle on a machine in the tobacco processing industry and/or on a packaging machine. A liquid jet is sprayed onto the glue-application nozzle to remove impurities on and around the glue-application nozzle. The method may also include suctioning the liquid and the removed impurities out of the area near the glue-application nozzle.  
           [0020]    The method according to the invention provides an efficient cleaning of the glue-application nozzles. In particular, no liquid or very little liquid spreads to the area surrounding the glue-application nozzle because the liquid is suctioned off. The suctioning operation preferably occurs at the same time as the liquid is admitted, thus making it possible to immediately suction off all of the liquid.  
           [0021]    For a particularly effective method that requires only small amounts of suction air, the cleaning preferably occurs in a cavity with a vacuum or at a pressure less than atmospheric. The liquid jet in particular is directed with comparably high pressure onto the glue-application nozzle. The ratio of liquid pressure to suctioning capacity preferably is adjusted such that the liquid jet is not or not essentially deflected on the way to the glue-application nozzle, but is still suctioned off completely.  
           [0022]    At least a portion of the cleaning device is preferably moved in the direction of the glue-application nozzle prior to cleaning of the glue-application nozzle. For one particularly preferred embodiment, the method is realized during an operational break of the packaging and processing machine. Owing to this preferred method, no additional time is required for the operational break of cleaning the glue-application nozzle.  
           [0023]    An extremely effective removal of the glue residues is using a pulsating liquid jet.  
           [0024]    The removal of the glue residues and/or the contamination is improved if a heated liquid is used for generating the liquid jet. Furthermore, the glue residues and/or the impurities can be removed easier if a cleaning agent is added to the liquid, for example, a solvent for glue.  
           [0025]    The nozzle can additionally be flushed from the inside, resulting in an improved cleaning, if glue is pumped through the glue-application nozzle during at least part of the cleaning operation.  
           [0026]    For the purpose of this invention, the term “close” also includes the immediately surrounding area. Within the framework of this invention, the term “impurities” also refers to glue residues. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    The invention is explained in the following with the aid of exemplary embodiments and by referring to the drawings, without restricting the general inventive idea.  
         [0028]    [0028]FIG. 1 is a cross-sectional side view of a cleaning device according to the invention.  
         [0029]    [0029]FIG. 2 is a schematic representation of another embodiment of the cleaning device according to the invention.  
         [0030]    [0030]FIG. 3 is a view of the embodiment of FIG. 2 in a different position relative to a glue-application nozzle.  
         [0031]    [0031]FIG. 4 is a view of the embodiment of FIG. 2, and illustrates glue being spread onto a material.  
         [0032]    [0032]FIG. 5 is a schematic representation of another embodiment of the invention.  
         [0033]    [0033]FIG. 6 is a schematic representation of another embodiment of the invention.  
         [0034]    [0034]FIG. 7 is a schematic representation of another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]    Identical or corresponding parts are given the same reference numerals in the drawings and will not be introduced again.  
         [0036]    [0036]FIG. 1 shows a cleaning device for cleaning a glue-application nozzle  1 . A cavity  20  is defined inside a casing  18  by a cleaning nozzle  2 , the casing walls of casing  18  and the glue-application nozzle  1 . Inside the cavity  20 , a water jet  14  is focused directly onto the glue-application nozzle  1 . To generate the water jet  14 , cleaning water  3  is pumped with a pump  4  from a water container  22  under pressure through a hose  9  and a connecting element  6  into the casing  18  and onto the cleaning nozzle  2 . As a result of a relatively high pressure, the cleaning water  3  is pushed through the nozzle and generates the water jet  14 . The pump can be, for example, pump model AT20, manufactured by the German company Almatec.  
         [0037]    The high-pressure water jet, e.g. with a pressure of 4 to 8 bar but preferably 6 bar, hits the glue-application nozzle  1  that is preferably arranged below the cleaning device and removes glue residues and other impurities from the glue-application nozzle  1 . A suctioning device  17  installed near the glue-application nozzle suctions off the respective mixture of cleaning water  3  and glue residues and/or contamination as contaminated water  16 . The suctioning device  17  generates a pressure less than atmospheric or a vacuum inside the cavity  20  to suction the contaminated water. The suctioning device  17  is connected to the cavity  20  via a hose  8 , a suction pipe  7  and an opening in the casing  18 . The cleaning device is ideally arranged precisely opposite the glue-discharge opening of the glue-application nozzle  1 .  
         [0038]    During breaks in the production of the machine, the cleaning device is fitted onto the glue-application nozzle  1  with the aid of a pivoting device and/or a translational device, for example, a short-stroke cylinder  11  in connection with a guide  13 . The short-stroke cylinder  11  can be, for example, a product of the German company Festo. The cleaning device is moved in direction  12  with the short-stroke cylinder  11 . After the casing  18  has been fitted onto the glue-application nozzle  1 , a sufficiently strong water jet or liquid jet  14  is generated and focused directly onto the contaminated nozzle region. The suctioning device is also activated.  
         [0039]    Owing to its high speed, the water jet  14  removes the glue residues and other contamination. The suctioning device  17  removes the resulting atomized fog and/or contaminated water and prevents water from leaking into the area around the nozzle. To improve the cleaning effect, the glue valve and/or the glue-application nozzle  1  can also be operated briefly, such that the outflow of glue  32  can additionally aid cleaning of the inside portion of the glue-application nozzle  1 .  
         [0040]    The cleaning nozzle  2  and the suctioning device are combined to form a compact component in the casing  18 . In the operating state, they form a chamber and/or cavity around the glue-application nozzle  1  to be cleaned. A pressure of less than atmospheric or a vacuum is created in the cavity, thus making it unnecessary to have an involved seal at the contact location between glue-application nozzle  1  and cleaning device. The cleaning water  3  can be heated for a better cleaning effect and/or cleaning agents can additionally be used.  
         [0041]    The necessary water pressure is generated with the pump  4 , for example a membrane pump manufactured by the German company Almatec. The pump  4  is located on a supply container, water container  22  or other water supply system. A flexible hose  9  connects the pump  4  to the flushing head and/or the casing  18 . Different nozzles, for example, nozzles produced by the company Spraying Systems, can optionally be used inside the casing for generating specific, desired jet characteristic.  
         [0042]    The mixture of water, glue and other contaminants can be suctioned out of the casing in different ways. One method is shown in FIG. 1, which depicts the suctioning device  17 . In this case, the solution resulting from the cleaning flows into the catch container of the suctioning device  17  and should be removed regularly. The suctioning device  17  can be a model AS 1100 INOX, manufactured by Einhell, a company located in Lindau, Germany.  
         [0043]    A different variant of the invention uses a compressed-air ejector  24  and is shown in FIGS.  2  to  6 . With the aid of suction air made available to the ejector  24  via an air-intake pipe  30 , the ejector  24  generates a pressure less than atmospheric or a vacuum in the suction pipe  7 . Thus, the liquid is moved to the hose  8  and finally into the contaminated water container  23  and/or, as shown in FIG. 6, into the mixed water container  37 . Ejectors, for example, ejectors produced by the German companies Fipa or Volkmann can be used. As an example, Volkmann model PV100 can be used. The Volkmann ejector has an air consumption, for example, of 0.95 Nm 3 /min at 6 bar and preferably operates with a vacuum at 300 mbar.  
         [0044]    [0044]FIG. 2 shows an intake pipe  21  by which the cleaning water  3  is fed from the water container  22  via a pump  4  through the cleaning nozzle  2 . A shut-off valve  26  is installed inline in the system, between the connecting element  6  and the hose  9 , and functions to respectively control the supply of cleaning water  3 . For this, the shut-off valve  26  is connected via a line  29  to a control device  28 . The suctioning capacity and/or the suctioning operation is also controlled by the ejector  24  and via a shut-off valve  27 , which controls the suction air in the air intake pipe  30 . The shut-off valve  27  is furthermore connected via a line  29  to the control device  28 . The shut-off valves  26  and  27  can be opened and closed with the control device  28  for desired cycles and/or desired times. FIG. 2 shows a position in which the casing  18  is at a distance to the glue-application nozzle  1 . In this position, the cleaning device is not in operation. No water jet  14  is generated and the suctioning device is not activated.  
         [0045]    The schematic representation in FIG. 3 is the same representation as in FIG. 2, except that the relative position of the casing  18  to the glue-application nozzle  1  is different. In this exemplary embodiment, the glue-application nozzle  1  fits against the casing  18  and/or has been moved in the direction of the glue-application nozzle until it makes contact with the nozzle  1 . In this position, the glue-application nozzle  1  can be cleaned.  
         [0046]    The exemplary embodiment shown in FIG. 4 illustrates how the glue-application nozzle  1  spreads the glue  32  onto a blank  33  conveyed in conveying direction  34 .  
         [0047]    In this position and/or during the predetermined function of the glue-application nozzle  1 , no water jet  14  is generated and there is no suctioning operation.  
         [0048]    In order to support and/or guide the blank  33 , FIG. 5 shows that the casing  18  is moved to the region of blank  33  such that a guide surface  36  makes contact with the blank  33  and guides the blank  33 . In this embodiment, the casing  18  serves a dual function.  
         [0049]    [0049]FIG. 6 shows a schematic view of another exemplary embodiment of a cleaning device according to the invention in which the cleaning liquid is used in a closed system. For this embodiment, mixed water  39  is filtered through a filter  38 , suctioned in via an intake pipe  21 , and supplied to the cleaning nozzle  2  via the hose  9 , the shut-off valve  26  and the connecting element  6 . The correspondingly contaminated water and/or mixed water is then again supplied by an ejector  24  to the mixed water container  37  via the suction pipe  7 , the ejector  24  and the hose  8 . A filter  38  can also be provided for the exemplary embodiments shown in FIGS.  1  to  5 .  
         [0050]    [0050]FIG. 7 shows another embodiment of the invention. The cleaning device of this embodiment has a longer and/or larger guide surface  36 . The material onto which the glue is spread is positioned precisely in the region of the glue-application nozzle  1 . Corresponding guide rails  41 , guide plates, pressure blocks or similar measures can be used to position the material. The combination of an extended guide surface  36  and a guide rail  41  is used in the embodiment shown in FIG. 7. The opening into which the glue-application nozzle  1  is inserted for the cleaning operation is flush with the sliding surface and/or the guide surface  36 . Alternatively, the suctioning opening of the device can be integrated so as to be flush with a sliding surface of a plate inserted for guiding the material, wherein the glue-application nozzle or the guiding device with suctioning device are designed such that they can be moved. However, it is also possible to provide the material guiding parts in the region of the flushing device with a recess through which the suctioning device can be pivoted against the glue-application nozzle.  
         [0051]    The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.