Patent Publication Number: US-10773871-B2

Title: Inner container made of plastic and transport and storage container for liquids comprising such an inner container

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a United States National Phase Application of International Application PCT/EP2014/064235 filed Jul. 3, 2014 and claims the benefit of priority under 35 U.S.C. § 119 of German Patent Application 10 2013 213 167.4 filed Jul. 4, 2013, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to an inner container made of plastic for transporting and storing liquids, said inner container comprising a filling neck in an upper bottom wall for filling the inner container and an outlet neck on a front side for connecting an outlet armature and a lower bottom wall interconnecting two side walls, a rear wall and a front wall of the inner container for supporting the inner container on a pallet base of a transport pallet which is provided with an outer mantle for receiving the inner container. Furthermore, the invention relates to a transport and storage container comprising such an inner container. 
     BACKGROUND OF THE INVENTION 
     Inner containers of the afore-mentioned kind are used as an exchangeable component of transport and storage containers, which serve to transport and store liquids and are commonly used as so-called circulating containers, which are filled repeatedly. To achieve a maximum turnover volume of the liquids filled into inner containers, it is substantial to ensure that the container is emptied as completely as possible so that the entire container volume is available for refilling in the next filling process. Furthermore, it is also important to achieve an emptying as complete as possible of the container in the interest of an economic, substantially complete utilization of the content of the container and to avoid costly purging and cleaning processes. 
     A substantially complete draining of the known inner containers may prove very elaborate and time-consuming in particular in connection with highly viscous filling products which exhibit good wetting properties with regard to the inner walls of the inner container because the shape of the container is substantially aimed at providing a container with a maximized container volume which is additionally adapted in terms of its exterior dimensions and its design to the receiving space defined on the transport pallet within the outer mantle. 
     With respect to emptying the inner container as completely as possible, particular problems arise in the storage of thixotropic liquids such as lacquers whose viscosity must usually be reduced by stirring in order to allow a subsequent removal of the lacquers from the container and subsequent processing of the lacquers by spraying surfaces to be lacquered, for example. After an incomplete emptying of the container, the viscosity of the resting liquid increases again so that the amount of lacquer remaining in the inner container has to be stirred up again before performing another lacquering process. 
     Stirring up a residual or partial amount which remains in the inner container as a result of a successive removal of partial amounts, for example, is necessary in practice not only with lacquers but basically with all liquids that may exhibit separation due to storage. Separated dispersions, for example, can be homogenized by stirring. A residual amount that cannot be stirred up, such as a separated lacquer, is useless and may have to be disposed of in a costly manner. 
     For stirring, stirrer devices are usually introduced into the inner container through the filling opening formed in the upper bottom wall of the inner container, by means of which the residual amount remaining in the inner container can be stirred up. To completely use up the lacquer remaining in the inner container, it is necessary that the residual amount can be stirred up as completely as possible, i.e. that the stirrable residual amount is minimized so as to be able to use up the entire content of the container in the economic interest of the lacquer processor. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to propose an inner container made of plastic for transporting and storing liquids as well as a transport and storage container comprising such an inner container which allows the container to be emptied to the largest possible extent even in case of thixotropic liquids. 
     According to the invention, the outlet neck of the inner container is arranged at a hopper bottom of an outlet hopper formed in the lower bottom wall, the outlet hopper having a front hopper wall, which comprises the outlet neck, and two lateral hopper walls which are inclined to each other in a V-shape, are arranged at a hopper angle α in relation to the horizontal and extend starting from a keel-shaped hopper base to a lower edge of a side wall, a keel line of the keel-shaped hopper base rising at a hopper angle β in relation to the horizontal from the outlet neck arranged below the front wall toward the rear wall. 
     The design according to the invention utilizes the lower bottom wall for forming an outlet hopper which allows even highly viscous liquids to drain off in the area of the lower bottom wall toward the hopper base because of the lateral hopper walls which are inclined to each other in a V-shape in connection with the hopper base which is keel-shaped and extends from the outlet neck toward the rear wall with a rising keel line so that it is ensured that the residual amount remaining in the inner container accumulates at the hopper base. Moreover, the keel-shaped hopper base forms a drain channel which extends from the outlet neck toward the rear wall. 
     The formation of such an accumulation which forms a bath of the residual amount is a prerequisite for being able to use a stirrer on the residual amount at all, i.e. for the stirrer to be able to become submerged in the bath of the residual amount, and for preventing the formation of liquid clusters outside of the area accessible to the stirrer to the largest possible extent. 
     In a preferred embodiment of the inner container, the keel-shaped hopper base is formed in the shape of a bowl with a concave cross-section and rising in a wedge-shaped fashion starting from the hopper bottom toward the rear wall. In this way, it becomes possible to form the lower bottom wall in such a manner that the gradient of the lateral walls inclined to each other in a V-shape continues in the area of the hopper base and because of its concave and wedge-shaped design, the hopper base forms a substantial portion of a reservoir that is formed in the lower bottom wall and that allows the stirrer to become submerged. 
     If the hopper angle α is between 25° and 50° in a cross-section of the inner container running through the filling opening, it is ensured on the one hand that a sufficient gradient of the hopper walls toward the keel-shaped hopper base is formed and on the other hand that a stirring mechanism can also be introduced into the hopper base as deeply as possible and with smallest possible distance to the side walls. 
     If, in addition, the hopper angle β is between 5° and 15°, a particularly advantageously optimized design of the lower bottom wall of the inner container becomes possible, which, with a container volume as large as possible, allows the formation of a particularly effectively designed reservoir in the lower bottom wall. 
     Preferably, the keel-shaped hopper base has, in the direction of the rear wall, an end portion with a transitional wall portion which extends horizontally toward the rear wall and which has a horizontal contour in a cross-section of the inner container and ends with a curved contour in the rear wall in a longitudinal section of the inner container so that the formation of liquid clusters, i.e. of surface areas on which liquid can accumulate in an undesired manner, is prevented in the critical transition area from the keel-shaped hopper base toward the usually evenly formed and vertically oriented rear wall of the inner container. 
     A particularly smooth transition with a surface free of bumps or indentations becomes possible if the curved contour has a constant radius and preferably ends in the rear wall without a gradient. 
     Preferably, the front hopper wall is inclined from a lower edge of the front wall toward the hopper bottom so that a recessed arrangement of the outlet neck with respect to the front wall of the inner container and a correspondingly recessed and thus protected arrangement of an outlet armature mounted on the outlet neck is possible. Furthermore, the inclined front hopper wall permits adapting the gradient angle of the front hopper wall to the gradient angles of the lateral hopper walls. 
     For a proper function of the outlet hopper, however, it is sufficient if, according to a possible embodiment, the front hopper wall is formed by a triangular extension of the front wall, said extension preferably extending in the plane of the front wall. 
     A particularly low flow resistance facilitating the emptying of the inner container is achieved in the inlet area of the outlet neck if the hopper bottom is formed in the shape of a cup and has a connecting surface for the outlet neck, said connecting surface being formed on a lower edge of the front hopper wall and being arranged parallel to the front wall of the inner container. 
     If, according to a particularly preferred embodiment, the inner container is provided with a stirring mechanism whose stirrer head reaches into a stirring space formed in the bottom wall, even smallest residual amounts can be accumulated in the stirring space and be stirred up by the stirring mechanism, which is combined with the inner container and whose stirrer head is suitably designed so as to be able to reach into said stirring space. 
     If the keel-shaped hopper base forms a groove-shaped drain channel extending from the outlet neck toward the rear wall, it is ensured that the residual amount remaining in the inner container accumulates at the hopper base. This is the case to a particular extent if the groove-shaped drain channel formed by the keel-shaped hopper base widens from the outlet neck toward the rear wall. 
     The transport and storage container for liquids according to the invention comprises an inner container made of plastic having the features discussed above, wherein the inner container is arranged with its lower bottom wall for support on a pallet base of a transport pallet provided with an outer mantle for receiving the inner container and a support means is arranged between the lower bottom wall of the inner container and the pallet base, said support means having a support surface that is adapted to the bottom wall. 
     The transport and storage container according to the invention thus allows using an inner container which has the advantages previously explained in detail above by simply combining a conventional transport pallet having an outer mantle with a support means. 
     The transport and storage container according to the invention permits using an inner container which allows improved emptying without needing to deviate from the transport pallet commonly used with a transport and storage container or from the commonly formed outer mantle in order to be able to utilize the advantageous effects of the inner container. 
     The combination of the lower bottom wall designed in a special manner as an outlet hopper with the support means adapted thereto allows forming a mechanical engagement connection between the inner container and the support means, said connection relieving the outer mantle from dynamic shear forces as they occur during transport, for example, so that the transport and storage container exhibits increased transport safety. 
     Particularly advantageous effects with regard to the total height of the transport and storage container and thus also for the tipping stability or stacking safety occur if, for forming the support surface for the bottom wall, the support means has a support frame with a recess for the outlet hopper and with a recess for passage of an outlet armature arranged on the outlet neck so that the outlet neck can be received in the support means in a recessed manner. 
     Preferably, the support frame has a support brace for supporting the inner container, said support brace bridging the recess for passage of the outlet armature arranged o the outlet neck. 
     If, according to an advantageous embodiment, the support means for forming the support surface for the lower bottom wall has a support depression, a particularly safe support of the inner container with optimal force transmission of the surface load acting from the inner container onto the transport pallet is realized. 
     To reduce the number of components of a transport and storage container, the support means can be formed contiguously in one piece with the pallet base, i.e. it can be produced as a molded part, for example. 
     It is particularly advantageous if the support means is formed as a blow-molded part so that the same technology can be used for producing the support means as for producing the inner container. 
     Alternatively, it is possible to form the support means as an injection-molded part so that, by way of an optimized design, the support means can be implemented with a minimum of material used and yet in a dynamically highly resilient fashion. 
     It is advantageous in particular for producing a support means that is composed of simple plane parts and yet permits adaption to the surface of the pallet base and to the lower bottom wall as well as to the outlet hopper of the inner container if the support means is formed as a bearing structure with a plurality of bearing ribs which are arranged transversely to the longitudinal direction of the inner container and are interconnected by horizontal connecting elements. 
     If the support means is formed as a bar structure with a plurality of interconnected bars, it is possible, for example, to implement the support means as a welded structure, in particular the use of pipes proving advantageous because of their high rigidity in proportion to the material used. If the bar structure is formed at least in part by bars of the outer mantle, the material used for production of the bar structure can be minimized by using already present bars of the outer mantle. 
     To avoid undesired surface pressure on the contact points between the bars of the bar structure and the inner container, it is advantageous if the bar structure for forming support surfaces is provided with bearing surfaces, which are preferably formed from sheet metal cuttings, so that welding them to the bars of the bar structure is easily possible. 
     In the following, a preferred embodiment of the inner container according to the invention and of the transport and storage container according to the invention will be explained in more detail with the aid of the drawings. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view showing a transport and storage container with an inner container arranged on a support means; 
         FIG. 2  is a perspective view showing the support means arranged on a transport pallet of the transport and storage container illustrated in  FIG. 1 ; 
         FIG. 3  is a view showing the inner container illustrated in  FIG. 1  in an isometric illustration, laterally from the front; 
         FIG. 4  is a front view of the inner container illustrated in  FIG. 3 ; 
         FIG. 5  is a lateral view of the inner container illustrated in  FIG. 3 ; 
         FIG. 6  is an isometric illustration of the inner container, laterally from the rear; 
         FIG. 7  is an isometric illustration of the inner container illustrated in  FIG. 3 , laterally from below; 
         FIG. 8  is a longitudinal-sectional illustration of the lower portion of the inner container illustrated in  FIG. 3  according to section line VIII-VIII in  FIG. 3  with a stirrer head arranged in the container interior; 
         FIG. 9  is a perspective view showing a cross-section illustration of the lower portion of the inner container illustrated in  FIG. 3  with the stirrer head arranged in the container interior; 
         FIG. 10  is an isometric illustration showing a support means; 
         FIG. 11  is a sectional illustration showing another embodiment of a support means; 
         FIG. 12  is an isometric illustration showing the support means illustrated in FIG.  11 ; and 
         FIG. 13  is an isometric illustration showing another embodiment of a support means. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a transport and storage container  20  which receives an inner container  25  made of plastic on a transport pallet  21  in an outer mantle  24  formed here as a cage mantle with vertical bars  22  and horizontal bars  23 . A support means  27  is arranged between the inner container  25  and a pallet base  26  of the transport pallet  21 , the inner container  25  being supported on said support means  27  with a lower bottom wall  28  of the inner container  25  illustrated in  FIG. 3 . 
     As shown in  FIGS. 3 to 5 , adjacent to the lower bottom wall  28 , the inner container  25  has a front wall  29 , two opposing side walls  30 ,  31 , a rear wall  32  and an upper bottom wall  33  opposite of the lower bottom wall  28 . 
     In the lower bottom wall  28 , an outlet hopper  34  is formed, including a front hopper wall  35  and two lateral hopper walls  36 ,  37  which are inclined to each other in a V-shape and which are connected to each other in a keel-shaped hopper base  38 . The inner container  25  has an outlet neck  40  on a front hopper wall  35  connected to a lower edge of the front wall  29  adjacent to a hopper bottom  39 , which forms the area of the outlet hopper  34  lying deepest, said outlet neck  40  serving to connect an outlet armature (not illustrated) which allows tapping a filling material from the inner container  25  which has been previously filled into the inner container  25  through a filling opening  41  in the upper bottom wall  33 . 
     The transport pallet  21  of the transport and storage container  20  illustrated in  FIG. 1  is implemented as a skid-type pallet with a center skid  42  and two outer skids  43 ,  44 , on which support legs  45  are arranged that support the pallet base  26  on which the support means  27  and the outer mantle  24  are arranged. 
     Departing from the transport pallet  21  embodied as a skid-type pallet illustrated in  FIG. 1 , the transport pallet can also be embodied as a frame pallet with a circumferentially closed base frame instead of the center skid  42  and the two outer skids  43 ,  44 . Departing from the embodiment illustrated in  FIG. 1 , in which the pallet base  26  is formed as a shaped sheet metal part and the support means  27  consists of a blow-molded part made of plastic, for example, the pallet base can also be a plastic component, wherein in particular an contiguous one-piece formation of the support means and of the pallet base from plastic or sheet metal material or another suitable material that allows a formation of the pallet base in one piece with a support means integrally formed thereto is possible as well. 
     As can be taken in particular from a combined view of  FIGS. 4 and 5 , the lateral hopper walls  36 ,  37  are arranged at a hopper angle α in relation to the horizontal and each extend from a lower edge  46 ,  47  of the lateral walls  30 ,  31  to the keel-shaped hopper base  38 . The hopper base  38  has a concave cross-section  48  indicated in  FIG. 7  and has a wedge-shaped form starting from the hopper bottom  39  toward the rear wall  32  of the inner container  25 , so that the lateral hopper walls  36 ,  37 , which are adjacent to the hopper base  38 , become narrower in the direction of the rear wall  32 , i.e. the preferably horizontally extending lower edges  46 ,  47  of the side walls  30 ,  31  and the lower edges  49 ,  50  of the lateral hopper walls  36 ,  37  come closer to each other in the direction of the rear wall  32  of the inner container  25 . 
     In the inner container  25  illustrated in  FIGS. 3 to 7 , the outlet hopper  34  is formed such that the lateral hopper walls  36 ,  37  ( FIG. 4 ) have a hopper angle α=30° and a hopper angle β=10° formed between a keel line  63  ( FIG. 5 ) of the keel-shaped hopper base  38  and the horizontal. 
     Irrespective of the illustrated embodiment examples, it is a general fact that the hopper walls as well as the keel line are preferably formed in a substantially even or straight manner, yet may also have a slight curvature of the surface or of the line at least in areas. In this case, the angles α and β refer to the tangents drawn to the surfaces and to the keel line. 
     As can further be taken in particular from  FIGS. 6 and 7 , the keel-shaped hopper base  38  has an end portion  52  in the direction of the rear wall, including a transitional wall portion  53  which extends horizontally toward the rear wall  32  and transversely to a longitudinal axis  64  and which is substantially formed as a triangular cylinder shell segment and here has a horizontal contour  65  in a cross-section of the inner container  25  and ends with a curved contour  66  in the rear wall  32  in a longitudinal section of the inner container  25 . 
     In  FIGS. 8 and 9 , for illustrating the advantageous design of the lower bottom wall  28  of the inner container  25 , a stirrer head  54  of a stirring mechanism introduced into a container interior  55  through the filling opening  41  ( FIG. 3 ) is shown. In the configuration of the stirrer head  54  illustrated in  FIGS. 8 and 9 , stirrer blades  56 , which are swung against a stirrer axis  57  in order to be introduced through the filling opening  41 , are illustrated in their swung-out operating configuration. When the stirrer head  54  rotates, the stirrer blades  56  operate in a stirring space  67  indicated by the hatching in  FIGS. 8 and 9 . 
     To make possible a minimized stirrable residual amount of a liquid accumulated in the area of the outlet hopper  34 , it is substantial that a maximum portion of the lumen of the outlet hopper adjacent to the outlet neck  40  and with minimal distance to the wall of the outlet hopper  34  is covered by the stirring space  67 . On the other hand, the design of the outlet hopper  34  in the lower bottom wall  28  should restrict the holding capacity of the inner container  25  as little as possible, both these afore-mentioned requirements having to be considered in an optimal design of an outlet hopper  34  formed in the lower bottom wall  28 . 
     The partial-section illustrations of the inner container  25  shown in  FIGS. 8 and 9  make clear that the above is achieved in the illustrated embodiment example in that a hopper angle α of 30° is formed between the lateral hopper walls  36 ,  37  and the horizontal and a hopper angle β between the keel line  63  of the concave hopper base  38  and the horizontal is 10°. 
       FIG. 10  shows the support means  27 , which in the present case is formed as a one-piece blow-molded part and has a support frame  58  with a recess  59  for receiving an outlet armature arranged on the outlet neck  40  of the inner container  25  illustrated in  FIG. 3 , for example. The support means  27  has a support depression  60  whose surface forms a support surface  61 . As can be taken from  FIG. 10 , the support surface  61  is designed such that partial surfaces are formed whose relative arrangement and contour correspond to the lateral hopper walls  36 ,  37  and to the hopper base  38  as well as to the transitional part  53  in the end portion of the hopper base  38  of the inner container  25 . 
     Departing from the support means  27  illustrated in  FIG. 10 , which can be produced as a blow-molded part or injection-molded part,  FIGS. 11 to 13  show examples of other possible designs. 
     For example,  FIGS. 11 and 12  show a support means  77  that is formed as a bar structure with a closed frame  78  and with bars  79 ,  80  that are bent in a U-shape and connected to the frame  78  and which consist of differently shaped pipe pieces. 
     As is shown in particular in  FIG. 11 , support bars  81 ,  82  are provided on the bars  80 , which form bar bridges for supporting the lower bottom wall  28  of the inner container  25  and are designed to have different heights corresponding to the surface contour of the lower bottom wall  28 . 
       FIG. 13  shows, as another possible embodiment, a support device  83  that is formed as a bearing structure with a plurality of bearing ribs  84  to  89  which are arranged transversely to the longitudinal axis  64  of the inner container  25  and are interconnected and secured in their relative arrangement by horizontal connecting elements  90 ,  91 . The respective height or shape of the bearing ribs  84  to  89  is selected such that an adaptation to the lower bottom wall  28  of the inner container  25  is possible ( FIG. 11 ). 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.