Patent Publication Number: US-6209590-B1

Title: Method and a system for filling ice cream into cup-shaped containers

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention concerns a method and an arrangement for the filling of cup-shaped packaging containers with viscous substances such as ice cream from a preferably continuously-operating filling nozzle disposed over a transported series of said cups, in that upon arrival at the nozzle the cups are successively raised quickly up to a position around the filling nozzle, and thereafter lowered in a slower movement corresponding to the increasing degree to which the cup is filled until the upper edge has been lowered to the level of the lower end of the nozzle, after which the cup is displaced horizontally, whereby it is achieved that the upper edge of the cup serves to cut off the string of the mass from the nozzle. In immediate connection herewith, the next cup is fed to the nozzle so that the filling of the next cup can begin without the flow from the nozzle having to be stopped. 
     This hereby involves relatively simple movements, i.e. a horizontal movement of the series of cups and a vertical movement of the cup in the filling position. It has proved, however, that the relevant vertical movement, which is typically controlled by means of a compressed air cylinder, is nevertheless difficult to control in an optimum manner for achieving a desirably precise top filling of the cups, i.e. without short filling of the cups and without surplus discharge of the filling mass from the nozzle. It is not least at the beginning of each daily production that ice cream masses with different viscosity and specific gravity can appear from the nozzle, and there can be quite long running-in periods during which the filling of the cups is so incorrect that many of these cups have to be discarded almost as unmarketable waste. 
     SUMMARY OF THE INVENTION 
     With the present invention, focus is placed on two different process aspects for solving or reducing these problems, i.e. partly by a continuous control weighing of the just filled cups, with the associated possibility for immediate feed-back control of the relevant process steps, and partly by use of a differentiated, controllable regulation of the vertical movements of the cups in relation to the filling nozzle, to which can also be added a control of the horizontal movement of the cups. 
     With the invention, a main consideration is thus that quite great advantages will be able to be gained by a regulation of the cup movement means in order to achieve that the cups are completely filled, and thereafter to carry out the process adjustments which are necessary for regulating the filling weight to a desired amount. 
     Here, the use of other means of movement for controlled vertical movement of the cups shall not be renounced, but with the invention it has been found that the ordinary air cylinders are not suitable for control as desired, while by making use of a servo-motor the sequence can be controlled in precisely the desired manner, i.e. with regard not only to speed and position but also power output. In principle, a servo-motor can control a reciprocating movement via a threaded spindle, but with the invention it has been found more expedient to let the motor pull on a vertically-disposed belt loop, which at its one side is in support connection with a supporting element for the cups in the filling station. A change between low and high speed can hereby be carried easily and with minimal influence of wear. 
     During the filling operation the cup and its supporting element will be affected not only by the weight of the already received filling mass, but also—and to a much higher degree—by the pressure exerted by the jet of the mass leaving the filling nozzle. The associated lowering of the cup, therefore, is not a matter of active lowering, but rather a matter of a controlled braking, and the said servo-motor is a perfect means for such a braking, inasfar as it can be ajusted to yield a suitable counter torque. 
     For a more detailed description of the desirable aspects of the invention, reference is made here to the drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic side view of a filling station according to the invention, and 
     FIG. 2 a )- f ) is a sequential series of views for the illustration of the filling sequence. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1 it is shown that a filling station  2  with an overlying filling nozzle  4  is fed by conveyer  6  with holes  8  in which there are empty cups  10 . The conveyer  6  can be a belt or a turn-table which is incremented in steps to bring the cups  10  to a position under the nozzle  4 . However, it will also lie within the scope of the invention for the conveyor to be moved continuously, while the nozzle  4  and an underlying height control system  12  for the cups is fed forwards and backwards in order to effect the desired filling of the cups. 
     The said height control system  12  consists of an upper bottom support plate  14  for the cups  10 , and from here a downwards-extending support rod  16  which, via a coupling part  18 , is firmly connected to the one vertical section of a belt loop  20  which extends between an upper and a lower reversing wheel  22 , one of which is driven by a servomotor  24  for the controlling up and down of the coupling part  18  along the shown arrow  26 . The cups  10  are fed to the filling station at a height at which their upper edges are lying on a level slightly below the mouth of the filling nozzle  4 . 
     In a position immediately after the filling nozzle  4 , the now filled cups are brought to rest on a weighing platform  28 , whereby the filling weight can be registered via a weighing unit  30 . 
     It is schematically shown that the filling mass is supplied to the nozzle  4  from a processing plant  3 , in which the mass if prepared with various parameter settings controllable from a control unit  5 , the weighing unit  30  is connected to this control unit. 
     As shown in FIG. 2 a ), an initial step will be that an empty cup  10  is fed in to a position under the nozzle  4 , with the upper edge of the cup lying so far down under the nozzle mouth that the edge of the cup will not interfere with a string  32  of filling material extending down from the nozzle. Immediately thereafter, the servomotor  24  is activated for the raising of the cup to the position shown in FIG. 2 b ), where the cup begins to receive the ice cream mass which is supplied to the bottom of the cup. 
     As already mentioned, the filling mass will hit the cup as a powered jet and will thus force the cup downwards. However, at this stage the servomotor is actuated to provide a torque that will effectively balance the jet pressure. It must be mentioned that in addition to this dynamic impact there will be a downwardly directed reaction force originating from the forcing up of the filling mass in the annular gap G between the outside of the filling jet and the inner wall of the cup, and also this force should be balanced out by the applied motor torque. It has been found that the width of this gap should preferably be 3-13 mm. 
     The motor  24  is then activated for the lowering of the cup at a speed which is controlled in such a manner that the cup is lowered at the same “volume speed” as the ice cream mass is introduced, i.e. during the lowering the cup will thus be held filled more or less to the level of the lower edge of the nozzle  4 , FIG. 2 c ). When use is made of preferred cups which are conical in shape, this means that the lowering speed must be controlled in a suitably decreasing manner. 
     Towards the end of the lowering movement as shown in FIG. 2 d ), i.e. at a detected “almost lowermost” position of the cup, a lowering at increased speed is effected, i.e. by a related increase of the moment of force with which the servomotor influences the lowering arrangement, so that as shown in FIG. 2 e ), there will now occur a certain drawing-down of an ice cream string part  32 ′ which is standing up to slightly above the general filling level in the cup and even to slightly above the upper-edge level of the cup. 
     As shown in FIG. 2 f ), when a cutting-over of the ice cream string  32 ′ is hereafter effected by horizontal displacement of the cup  18 , the drawn-up string  32 ′ will distribute itself for top filling of the cup in connection with its sideways movement from the nozzle  4 , and immediately afterwards cf. FIG. 2 f ) a new cup  18 ′ will be introduced under the nozzle  4  for the execution of the filling operation. 
     By an appropriate monitoring, a control of the filling can thus be established very easily by the moving means for the cups being controlled for total filling of the cups immediately from the start. If or when it is ascertained by the immediately subsequent control weighing in the weighing station  30  that the totally filled and herewith marketable cups do not completely satisfy exact desired criteria regarding precise product weight, in the subsequent production it can, however, based on said monitoring, be quickly brought about that signals can be sent to the production equipment such that this normalises the situation, in that there shall thus merely be carried out a subsequent adjustment of the speed profile with which the motor  24  influences the cups  8  in order to ensure that these are still precisely filled, i.e. with neither over- nor under-filling. 
     The invention can be used in connection with both small and large cups, ranging e.g. from cups with a height of 80 mm and a diameter of 40 mm to one liter cups and even rectangular containers of five liters or more. Up to a volume of approximately one liter it has been found possible to operate with a capacity of some 80 filling cycles per minute.