Patent Publication Number: US-2022219374-A1

Title: Method and device for producing containers, filled with liquid filling material, from thermally conditioned preforms

Description:
The invention relates to a method according to the preamble of claim  1  and a device according to the preamble of claim  7 . 
     Generic methods and devices are used in container forming and filling systems. In such systems, thermally conditioned preforms are simultaneously expanded into the desired container shape by introducing liquid filling material under high pressure at a forming and filling station, and the containers being formed are filled. During the forming and filling process, the preforms are arranged in a mold of the forming and filling station which defines the final desired container shape. 
     The preforms are thermally conditioned, e.g., in heating lanes or heating sections, as described, for example, in WO 2012/083910 A1. 
     The mentioned forming and filling systems are known in the prior art. Reference is made to DE 10 2010 007 541 A1 in this regard. 
     Forming and filling systems are intended to replace conventional systems in which a separate blow molding and a separate filling station are provided. In conventional systems, the thermally conditioned preforms are, in two steps, first formed into the finished containers in a blow molding station by introducing gas under high pressure, which containers are then filled in the filling station in a next step. 
     In the case of the forming and filling systems mentioned here, however, forming and filling takes place in one step. As already mentioned above, the filling material is fed into the preforms under high pressure at the desired metering rate and the desired number of cycles. Typical filling times are in the range of 100-150 ms, which requires volume flows of up to 20 liters/s and pressures of up to 40 bar. 
     With regard to these requirements, devices of the generic type are provided in known forming and filling systems, for example, which are intended to enable the required pressures and volume flows. 
     The filling material is provided by a filling material source, usually a filling material reservoir, which is, via a feed line, connected to a filling valve that controls the flow to the preforms. 
     Usually, the filling material reservoir is a pressure reservoir pressurized by a pressure pump, which pressure reservoir discharges the product into the feed line at a defined pressure. 
     In known devices, furthermore, a displacement pump is arranged between the filling material source and the filling valve. The filling material source is in fluid communication with the displacement pump via a first inlet-side section of the feed line, which in turn is connected to the filling valve via a second outlet-side section of the feed line. 
     The displacement pump serves in particular to provide the required pressure and volume flow with which the filling material is discharged into the preform or the container being formed via the second section of the feed line when the filling valve is open. 
     In methods and devices of the generic type, it is provided that one displacement pump is associated with one forming and filling station in each case. This represents a relatively high structural effort and also requires high maintenance. Such prior art is shown in WO2018/141347 A1 and DE 10 2018 106 930 A1. 
    
    
     It is the object of the invention to provide a method with which this effort can be reduced. It is another object to provide a device that requires less installation space and can be operated more cost-effectively. 
     These objects are achieved with a method that has the characterizing features of claim  1  and with a device that has the characterizing features of claim  7 . 
     Advantageous configurations are specified in the dependent claims. 
     As is known from the prior art, the method according to the invention works with a filling material source which provides the desired amount of filling material. 
     The filling material source is in flow communication with the forming and filling station. 
     Furthermore, a displacement pump is provided between the filling material source and the forming and filling station, which displacement pump generates the pressure and volume flow required for filling and forming the preform, or the different volume flows required. Usually, the preforms are not filled and formed at a constant volume flow. Often a lower volume flow of, e.g., 2 liters/sec, is used initially, then a higher volume flow of, e.g., 5 liters/sec, and finally again a lower volume flow of, e.g., 2 liters/sec, is used. These are only exemplary values. Depending on the material and volume of the preform, other volume flow profiles with pumping rates of up to 20 liters/sec, for example, can also be used. These can be implemented without any problems by appropriate control of the displacement pump. 
     The term filling material source is to be interpreted broadly. It can be, for example, a dispensing station at a system, with which the filling material is produced. If the device is located, for example, at a different location, a filling material reservoir is usually used as the source. 
     The discharge of filling material from the filling material source can take place without pressure or under pressure. 
     In the case of pressure-free discharge, the displacement pumps would have to be designed in such a way that they can suck in the filling material. Alternatively, it would also be conceivable to provide a further pump in the feed line, with which the filling material can be pumped from the filling material source to the displacement pump. 
     Preferably, a filling material source is provided which discharges the filling material under pressure. It can be, for example, a filling material pressure reservoir to which filling material is applied by a continuously running pump under pressure. The use of a source that discharges the product under pressure has hydraulic advantages and allows a smaller design of the displacement pumps, for example. 
     According to the invention, it is now provided that at least two forming and filling stations are associated with each displacement pump, at which forming and filling stations the displacement pump can pump filling material into the preforms. 
     A pumping process would look something like this that first the pump is started and the filling valve of the associated filling and forming station is opened. Then, the pump would apply the filling material to the preform at a desired volume flow profile and pressure, and after completion of the forming and filling process, the filling valve would be closed again and the pump would be stopped. This process is also to be referred to hereinafter by the term “supply”. 
     It is conceivable that a displacement pump supplies the at least two associated forming and filling stations in parallel or in a temporally overlapping manner. For this purpose, it would be sufficient to adjust the filling material volume and the pumping capacity of the displacement pump accordingly. However, in industrial processes, the temperature-controlled preforms are fed one after the other to the forming and filling stations of a device and processed further as soon as possible in order to prevent the preform from cooling down too much before it is reformed. 
     Here, it can be machines that work in cycles or, preferably, machines that operate according to the rotary principle, in which the forming and filling stations are arranged on a rotating work wheel. In any case, in such processes no two preforms are available for filling and shaping at the same time over the same period of time. A parallel filling of these two preforms, which are offset by at least one cycle or temporally, with a matching volume flow profile and with one pump would therefore be problematic in industrial processes. Filling that overlaps temporally would only be possible with a constant volume flow. 
     It is therefore preferably provided that the displacement pump supplies the forming and filling stations associated with it successively. 
     It is furthermore preferably provided that a plurality of displacement pumps are provided which together supply a plurality of forming and filling stations in a defined sequence. In this configuration it is provided that, between the forming and filling stations supplied by a pump, there is at least one forming and filling station which is supplied by another displacement pump. In this way, higher cycle rates or, in the case of devices with a work wheel, higher rotational speeds can be achieved. It is conceivable, e.g., that the displacement pumps successively each supply the first forming and filling station associated with them and then, correspondingly, the at least one further associated forming and filling station. In the last-mentioned configurations, filling of preforms that overlap temporally would then also be possible. 
     If one takes as an example a work wheel with a cycle time of 1800 ms, on which the forming and filling stations are arranged, 6 stations could be supplied successively with a pump that takes 300 ms for a forming and filling process. With 2 pumps that alternately supply successive stations, 12 stations could be supplied, with 3 pumps  18 , and so on. 
     The invention also relates to a device for producing containers filled with liquid filling material. 
     As is known from the prior art, in the device filling material is discharged from a source into a feed line to the filling valve of a forming and filling station. A displacement pump is provided between the filling material source and the forming and filling station, which is connected to the liquid source via an inlet-side section of the feed line, and to the filling valve of the forming and filling station via an outlet-side section. The displacement pump is designed in such a way that it can pump the filling material provided by the filling material source with the desired volume flow profile and pressure into a preform. 
     With regard to the interpretation of the term “filling material source”, reference is made to the statements above. In addition, it should be mentioned that the filling material source, for example a reservoir or a pressure reservoir, can be part of the device, but can also be provided separately, that is to say externally, for this purpose. 
     According to the invention it is provided that the displacement pump is in flow communication with at least two forming and filling stations, and is controlled and designed in such a way that it supplies the stations in particular successively with the required product volume at the desired rate. 
     Compared to the devices known from the prior art, in which one displacement pump is associated with one forming and filling station in each case, the device according to the invention represents a considerable structural saving. 
     It is conceivable that the displacement pump is a reciprocating piston pump, which in each case executes partial strokes to supply the associated forming and filling stations. The disadvantage of reciprocating piston pumps is that they first have to be filled with the filling material volume and then discharge it in a second step. The piston pump is filled via a loading valve, which makes the construction relatively complex and slow. 
     Circular pumps are therefore preferably provided as displacement pumps with, for example, meshing pistons or gear wheels, in particular screw, rotary or rotary piston pumps. Rotary pumps do not require any loading valves and can usually be cleaned without leaving any residues by means of flushing, etc. CIP cleaning (cleaning in place) is thus possible. In addition, they can convey forwards and backwards without any problems, which can be utilized, for example, after the forming and filling process to set a desired filling level in the container or in the case of a pressure-free liquid source. 
     To supply a forming and filling station, it is only necessary to switch on the pumps and generate the desired volume flow profile by setting a defined rotational speed, for example of the meshing circular or rotary pistons. Suitable pumps are known in the prior art and are available on the market in many different versions. 
     As is known from the prior art, in the device according to the invention, the forming and filling stations can preferably be arranged on a rotating work wheel. The displacement pumps can also be arranged on the work wheel. However, it is also conceivable to provide the displacement pumps outside the working wheel and to connect them to the working wheel and the forming and filling stations arranged thereon via a rotary feedthrough. The same applies to the filling material reservoir or filling material pressure reservoir. These can also be provided outside the work wheel or rotating with it. Furthermore, a filling material source can be associated with each displacement pump. It is also conceivable, however, that a source, e.g., filling material pressure reservoir with a corresponding design, is connected to several displacement pumps. 
     The invention will be explained in more detail below with the aid of two figures. 
       FIG. 1  shows an exemplary embodiment of the device and method according to the invention, and  FIG. 2  shows another exemplary embodiment. 
       FIG. 1  shows a device  10  in which four forming and filling stations  11 ,  12 ,  13  and  14  are arranged on a work wheel  15  which rotates in the direction of arrow  16 . Usually, more forming and filling stations are provided on a work wheel, e.g.  12 . The reduction to four stations is done for reasons of clarity. Preforms  28 , which are thermally conditioned, are transferred to the work wheel or a forming and filling station arranged thereon by a device (not shown) in one position. In the case shown, this is, e.g., the position in which the forming and filling station  11  is located. The preforms  28  are then formed into containers and filled with further rotation of the working wheel  15  (not shown) and the finished, filled containers in, for example, the position in which the forming and filling station  14  is located, are handed over to a further treatment device, e.g. a closer or to a labeler. 
     Each of the forming and filling stations  11 - 14  has a filling valve  16  and a mold  17  which defines the final shape of the preform to be filled and formed. Outside the work wheel  15 , a filling material pressure reservoir  20  is provided, to which filling material is applied by a pump (not shown). As mentioned above, a filling material pressure reservoir represents a preferred configuration of a filling material source. However, other filling material sources are of course also conceivable. 
     The filling material pressure reservoir  20  is in fluid communication with displacement pumps  23  and  24  via inlet-side sections  21  and  22  of a feed line. The pumps  23  and  24  for their part are in flow communication with the forming and filling stations  11 - 14  via outlet-side sections  25  and  26  of a feed line. 
     In the case shown, the displacement pump  23  is associated with the forming and filling stations  12  and  14 , while the displacement pump  24  supplies the forming and filling stations  11  and  13 . The forming and filling station  11  is first supplied by the pump  24 . With further rotation of the working wheel  15 , a new preform  28  is then inserted into the forming and filling station  14  and this preform is filled by means of the other displacement pump  23 . The next step is the forming and filling station  13 , which in turn is supplied by the pump  24 , etc. 
     It is understood that, as already stated above, further forming and filling stations can be arranged on the work wheel, e.g.  12 . Of these 12 forming and filling stations, at least two, but also more stations, can each be supplied by one displacement pump. Conceivable would be, e.g., to provide four pumps for a work wheel with  12  positions, each supplying three forming and filling stations. The supply of successive forming and filling stations by different displacement pumps has the advantage that faster cycle rates or rotational speeds of the work wheel can be implemented. 
     As already stated above, in the case shown, the filling material is provided under pressure by the pressure reservoir  20 , while the displacement pumps  23  and  24  provide the required volume flow and pressure during the filling and forming of the preforms. Volume flows of up to 20 Its, for example, are conceivable. Usually, the volume flow varies during filling. It is conceivable, e.g., to begin with a lower volume flow, then to increase it and then to lower it again towards the end of the filling process. It is of course also conceivable to provide other volume flow profiles. This essentially depends on the material of the preforms etc. 
       FIG. 2  essentially shows a device  30  similar to that shown in  FIG. 1 . 
     Again, there is a work wheel  31  on which the forming and filling stations  32  and  33  are arranged. A preform  28  is inserted into the forming and filling station  32 . Here, too, a filling material pressure reservoir  34  is provided, which provides filling material under pressure. The filling material pressure reservoir  34  is connected to a displacement pump  36  via an inlet-side section of a feed line  35 . The displacement pump  36  is in turn connected to the filling stations  32  and  33  via an outlet-side section  37 . In contrast to the device shown in  FIG. 1 , the pressure reservoir  34  and the displacement pump  36  are arranged on the working wheel  31  so that they rotate together. The advantage is that the distance between the displacement pump and the filling valve is relatively short. On the other hand, it must also be taken into account that the arrangement of components on the work wheel  31  increases its weight, which under certain circumstances has design disadvantages.