METHOD AND DEVICE FOR THE PRODUCTION OF FILLED CONTAINERS FROM THERMALLY CONDITIONED PREFORMS
20200070397 · 2020-03-05
Inventors
Cpc classification
B29C49/685
PERFORMING OPERATIONS; TRANSPORTING
B29C49/46
PERFORMING OPERATIONS; TRANSPORTING
B29C49/68
PERFORMING OPERATIONS; TRANSPORTING
B29C49/6458
PERFORMING OPERATIONS; TRANSPORTING
B29C49/6436
PERFORMING OPERATIONS; TRANSPORTING
B29C2049/4664
PERFORMING OPERATIONS; TRANSPORTING
B29C2949/0715
PERFORMING OPERATIONS; TRANSPORTING
B29C49/78
PERFORMING OPERATIONS; TRANSPORTING
International classification
B29C49/64
PERFORMING OPERATIONS; TRANSPORTING
B29C49/78
PERFORMING OPERATIONS; TRANSPORTING
B29C49/46
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method and device for producing containers filled with liquid content from preforms made of thermoplastic material. The liquid content is fed as a pressure medium into thermally conditioned preforms during a forming and filling phase in a mold of one of a plurality of forming stations arranged circumferentially spaced apart on a common, continuously rotationally driven working wheel. A compensating device compensates for thermal consequences of centrifugal force acting on the liquid content fed into the preform during the forming and filling phase. The compensating device imparts a temperature profile to the preform in a circumferential direction, which is not point-symmetrical in relation to a longitudinal axis of the preform to produce a thermally differentiated partial circumferential region. The preform is inserted into the mold such that the thermally differentiated partial circumferential region faces in a radial direction of the working wheel.
Claims
1-13. (canceled)
14. A method for producing a container filled with at least one liquid content from a preform made of a thermoplastic material, said method comprising: thermally conditioning the preform along a heating zone in a heating device; and subsequently, during a forming and filling phase in a mold of a forming station, feeding the at least one liquid content into the preform as a pressure medium and thereby simultaneously forming and filling the container with the at least one liquid content; wherein the forming station is one of a plurality of forming stations arranged circumferentially spaced apart on a common, continuously rotationally driven working wheel at a radial distance from an axis of rotation of the working wheel, wherein a compensating device is used to compensate for thermal consequences of centrifugal force acting on the at least one liquid content fed into the preform during the forming and filling phase, wherein the compensating device is a temperature control device, which imparts to the preform a temperature profile in a circumferential direction which is not point-symmetrical in relation to a longitudinal axis of the preform and thereby produces a thermally differentiated partial circumferential region in the preform, and wherein the preform is inserted into the mold in such an alignment that the thermally differentiated partial circumferential region is facing in a radial direction of the working wheel.
15. The method according to claim 14, wherein, while the preform is being formed into the container, the preform is guided and stretched in a direction of its longitudinal axis at least for a time by a stretching rod.
16. The method according to claim 14, wherein the thermally differentiated partial circumferential region is heated more strongly than remaining circumferential regions of the preform.
17. The method according to claim 14, wherein the temperature profile imparted to the preform in the circumferential direction is regulated or controlled as a function of a selected circumferential speed of the working wheel.
18. The method according to claim 14, wherein the compensating device is arranged in the heating zone of the heating device.
19. The method according to claim 14, wherein the thermally differentiated partial circumferential region faces radially outward after insertion of the preform into the mold of the forming station.
20. The method according to claim 14, wherein the container is rotationally symmetrical about its longitudinal axis, is formed with n-fold symmetrical rotation, and wherein n is greater than 4.
21. The method according to claim 20, wherein n is greater than 8, and wherein the container is substantially circularly symmetrical.
22. The method according to claim 14, wherein the thermally differentiated partial circumferential region has a partial circumferential angle of less than 180.
23. The method according to claim 22, wherein the partial circumferential angle is less than 90.
24. A device for producing containers filled with at least one liquid content from preforms made of a thermoplastic material, said device comprising: a plurality of forming stations each having a forming and filling head and a mold, wherein each forming station is configured to feed the at least one liquid content into one of the preforms as a pressure medium and thereby simultaneously form the one of the preforms into a container and fill the container with the at least one liquid content during a forming and filling phase in the mold; and a heating device for thermally conditioning the preforms along a heating zone; wherein formation of the container takes place against an inner wall of the mold with the mold being closed, wherein the plurality of forming stations are arranged circumferentially spaced apart on a common, continuously rotationally driven working wheel at a radial distance from an axis of rotation of the working wheel, wherein the device further comprises a compensating device to compensate for thermal consequences of centrifugal force acting on the at least one liquid content fed into the preforms during the forming and filling phase, wherein the compensating device is a temperature control device, which is Imparts a temperature profile in the preforms, wherein the compensating device further has a preform alignment device for aligned insertion of the temperature-profiled preforms into respective molds of the plurality of forming stations, wherein the temperature control device is configured to impart the temperature profile in the preforms in a circumferential direction, which is not point-symmetrical in relation to a longitudinal axis of the preforms and thereby produce a thermally differentiated partial circumferential region in the preforms, and wherein the preform alignment device is configured to insert the preforms into the respective molds in such an alignment that the thermally differentiated partial circumferential region is facing in a radial direction of the working wheel.
25. The device according to claim 24, wherein the forming station has a stretching rod configured to stretch the preform in a direction of its longitudinal axis at least for a time during the forming and filling phase.
26. The device according to claim 24, wherein the temperature control device is arranged in the heating zone of the heating device.
27. The device according to claim 24, wherein the temperature control device is configured such that the thermally differentiated partial circumferential region is heated more strongly than remaining circumferential regions of the preforms.
28. The device according to claim 24, wherein the preform alignment device is configured such that the thermally differentiated partial circumferential region is facing radially outward after insertion of the preform into the mold of a forming station.
29. The device according to claim 24, wherein the inner wall of the mold is configured to produce the container such that the container is rotationally symmetrical about its longitudinal axis, and has n-fold symmetrical rotation, wherein n is greater than 4.
30. The device according to claim 29, wherein n is greater than 8, and wherein the inner wall of the mold is configured to produce a container having a substantially circular symmetry.
31. The device according to claim 24, wherein the temperature control device is configured to control or regulate the temperature profile of the preforms dependent on a circumferential speed of the working wheel.
32. The device according to claim 24, wherein the thermally differentiated partial circumferential region has a partial circumferential angle of less than 180.
33. The device according to claim 32, wherein the partial circumferential angle is less than 90.
Description
[0027] Additional advantages, features, and details of the invention result from the exemplary embodiments described in the following with reference to the schematic drawings. The following is shown:
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038] The structure of a combined forming and filling machine 10 essentially known from the prior art is shown in
[0039] After sufficient temperature control, also known as thermal conditioning, the preforms 14 are transferred by a transfer wheel 122 to a working wheel 110, which is arranged so as to rotate, i.e. can be circumferentially driven about a vertical machine axis MA, and/or to forming and filling stations 16, which are arranged on the working wheel 110 distributed around the circumference. The working wheel 110 is equipped with a plurality of such forming and filling station 16, in the region of which both forming of the preforms 14 into the schematically shown containers 12 as well as filling of the containers 12 with the intended content take place. The forming of each container 12 in this case takes place simultaneously with the filling, wherein the content serves as a pressure medium during forming.
[0040] After the forming and filling, the containers 12 are taken from the working wheel 110 by a removal wheel 124, further transported, and supplied to an output zone 126. The working wheel 110 circulates continuously at a desired circumferential speed during production operation. During a revolution, the insertion of a preform 14 into a forming and filling station 16, the expansion of the preform 14 into a container 12 including filling with a content and optionally including stretching, in the event a stretching rod is provided, and the removal of the container 12 from the forming and filling station 16 take place.
[0041] According to the embodiment in
[0042] Various thermoplastic materials can be used as the material for the preforms 14. Examples include polyethylene terephthalate (PET), polyethylene (PE), polyethylene terephtalate (PEN), or polypropylene (PP). The dimensions as well as the weight of the preforms 14 are adapted to the size, the weight, and/or the shape of the containers 12 to be produced.
[0043] A plurality of electrical and electronic components are typically arranged in the region of the heating device 116. Moreover, the heating mechanisms 118 are provided with moisture-sensitive reflectors. Because a filling and forming of the container 12 takes place in the region of the working wheel 110 while using the liquid content, it should be ensured that unintentional entry of moisture is prevented in the region of the heating device 116 to prevent electrical problems. This can take place, for example, by means of a partition mechanism 132, which at least offers spray protection.
[0044] Moreover, it is also possible to suitably adjust the temperature of the transport elements for the preforms 14, said transfer elements being used in the region of the transfer wheel 122, or to impact with pressurized gas such that adhering moisture cannot reach the region of the heating device 116.
[0045] The preforms 14 and/or the containers 12 are preferably handled using tongs and/or the outlet section 22 is handled, at least in areas, by clamping mandrels or dowels impinging from the interior or exterior. Such handling means are likewise well-known from the prior art.
[0046] In a principally sectional view through a forming and filling station 16 in addition to the molded container 12,
[0047]
[0048] When implementing the desired thermally differentiated circumferential region 14a of the preform 14, it would be possible to maintain the preform 14 in a non-rotatable manner. However, it is also possible to implement a rotation of the preform 14 about its longitudinal axis 8 with an incremental movement or continuously and, in doing so, to switch on or release the radiant heater 37 in cycles when the circumferential region 14a is aligned so as to face the radiant heater 37.
[0049] The temperature-profile-creation device 36 can be arranged, e.g., in the heating device 116, e.g. at the end of the heating zone, and resemble the heating mechanisms 118 provided in the heating device 116. For example, it is possible to adjust the temperature of the preform 14 in the circumferential direction uniformly initially in advance and subsequently to create the thermally differentiated region 14a with the help of the described temperature-profile-creation device 36, e.g., in that a preform 14 is guided passed a heating mechanism 118 in a non-rotatable manner.
[0050] It is also conceivable to provide both cooling of a first circumferential region, as explained by means of example in
[0051] In a view from above,
[0052] Multiple heating mechanisms 118 are provided in the linear region 42 on the left in
[0053] There are also heater boxes 118, 36 located on the opposite linear region 42 of the heating zone, through the heating device 116. The two heater boxes 118 the preforms 14 initially pass through on this section of the heating zone are structurally similar to the previously described heater boxes 118 for the uniform circumferential temperature control of the preforms 14. This is followed by a gap as well as two heater boxes 36 required for the thermal differentiation of a partial circumferential region 14a of the preforms 14 further in the direction of the preform movement, said boxes differing in their structure from the previously mentioned heater boxes 118. In this case as well, multiple radiant heaters are typically arranged on a first side of the heater box 36. However, there is optionally no reflector arranged on the opposite side of the heater box 36. This is intended to ensure that the preforms 14 guided through these thermal differentiation heater boxes 36 are not temperature-adjusted equally on the two opposite sides. This can also be achieved or further enhanced in that radiant heaters are used, which emit a radiation with a high portion of the radiation in a wavelength range which is absorbed by the preform material to a higher degree than with the heater boxes 118 for the uniform circumferential temperature control. In this manner, a desired temperature profile can be created in the circumferential direction, namely a circumferential region with an excellent temperature, at present with a higher temperature, namely the circumferential region facing the radiant heaters. The remaining circumferential regions have a lower temperature, namely the circumferential regions of the preform 14 facing in the direction of movement and opposite the direction of movement and the circumferential region facing away from the radiant heater.
[0054]
[0055] The engagement belt 46 has a belt drive 47 in the exemplary embodiment shown. The engagement belt 46 is designed in this case such that an engagement in the transport means 33 takes place such that there is no rotation about the longitudinal axis of the preforms when passing through the heater boxes 36 designed for thermal differentiation. To this end, it is provided, for example, that the engagement belt 46 runs at the same speed as the transport chain 50. It is possible, for example, for a synchronization to take place between the transport chain 50 and the engagement belt 46. It would also be conceivable, however, for the engagement belt 46, for example, to not have its own drive but rather, for example, carriers, which engage the transport chain 50 and are then carried along by the transport chain 50. In this manner, the speed of the transport chain 50 and of the engagement belt 46 can be evenly maintained in a simple manner.
[0056]
[0057] In the region between the heater boxes 118 for the uniform circumferential temperature control and the heater boxes 36 for the thermal differentiation of a circumferential region, this mandrel rotary belt 51 is guided away from the transport chain 50 and the mandrel rotary belt 51 is thereby out of engagement with the gear wheels 52 of the transport means 33. This guiding away is provided so that the second engagement mechanism 45 can engage the gear wheel 52 without the mandrel rotary belt 51 showing a fault. To this end, the mandrel rotary belt 51 is guided externally at the second engagement mechanism 45 and at its deflection and guide rollers 48, 49. Outside of the region of the heater boxes 36 for the thermal differentiation of a circumferential region and after the engagement belt 46 is returned for a complete circulation, the mandrel rotary belt 51 again extends close to the transport chain 50 and again engages with the gear wheels 52 of the transport means 33 formed, e.g. as transport mandrels, in the left linear region 42 of the heating device 116.
[0058] The enlarged cutout from
[0059] The engagement belt described in reference to
[0060] An example of an engagement chain, which has a significantly more complex structure in comparison to the previously mentioned engagement chain according to the exemplary embodiment in
[0061]
[0062] The upper component 53 and the lower component 54 of the second engagement mechanism 45 are linked to a coordinated rotational movement, which is not shown. It is also conceivable here to provide both components 53, 54 with their own drives, which function in a manner coordinated with one another, in order to achieve a uniform and synchronized rotational movement. However, it is also conceivable for only one of the two components 53, 54 to have a drive and, for example, the other component to be driven by means of a coupling motion. However, it is also possible for one or both components to engage the transport chain 50 by means of carriers and be carried along by the transport chain 50. This is shown in
[0063] Essentially, it may be provided, e.g., that the carrier 44 has an engagement element, e.g. a blocking element, which engages the rotary drive body 52 of the transport mandrel 33 in a manner to prevent a rotation, as soon as the carrier 44 is placed in carrying engagement with the transport chain 50 in a cam-controlled manner. The blocking elements would then be moved with the carriers and, e.g., simultaneously placed in engagement and out of engagement. To this end however, the lift-off of the mandrel rotary belt 51 shown in
[0064]
[0065]
[0066] This design further enables the transport mandrel 33 and the preform 14 being held thereby to be maintained not only in a non-rotatable manner but specifically to twist about a certain angle of rotation, namely when the swivel movement of the swivel lever 59 is designed such that the belt pulley segment 63 not only holds the gear wheel 52 in a certain position but rather the swivel lever 59 could be more strongly swiveled, for example, in a third region of the control curve 56 in that the pinion 61 thereby rotates even further and the belt pulley segment 63 thereby rotates even further such that, as a result of the comb-like engagement with the gear wheel 52 of the transport mandrel 33, this gear wheel 52 and thus also the transport mandrel 33 is twisted about a certain angle. This can be used, e.g., as a preform alignment device, because the preform 14 should be inserted into the forming station 16 in a certain alignment and must possibly have to be rotated specifically for this.
[0067] A plurality of further suitable alignment devices for preforms are known in the prior art, e.g., devices interacting with alignment structures on the preform or with optical markings on the preform. WO 2016/180510 A1 shows examples and mentions examples in the prior art, which are essentially suitable also as preform alignment devices for the present invention in order to align the thermally differentiated circumferential region of the preform in the desired manner for transfer to the forming stations. Reference is explicitly made with regard to this to the content of WO 2016/180510 A1 and to the content of the documents mentioned therein as the prior art.