Abstract
A heating apparatus that includes a plurality of heating devices for temperature conditioning of preforms made of a thermoplastic material to a temperature and temperature distribution suitable for blow molding, and a transport chain guided on a revolving chain path. The preforms are transported through the heating apparatus by the transport chain along a transport path. Along a heating section that is part of the transport path, the plurality of heating devices are stationarily arranged one after another in a transport direction. On at least one side facing the heating devices, counter reflectors are provided, which together with the heating devices form a tunnel-like heating area through which the preforms are transported for heating. At least one counter reflector travels along with the preform through the heating section.
Claims
1. An apparatus for heating, transporting and handling preforms made of a thermoplastic material along a transport path through a heating section of a blow molding machine, the apparatus comprising: a plurality of heating devices stationarily arranged one after another relative to the transport path; a transport chain that is guided on a revolving chain path that, in the heating section, determines the transport path of the preforms; and a plurality of chain-link-type transport elements connected to the transport chain; wherein each of the plurality of chain-link-type transport elements includes a holding apparatus for holding onto a respective one of the preforms and a counter reflector for reflecting heating radiation from the plurality of heating devices onto the respective one of the preforms held by the holding apparatus, and wherein the counter reflector is movably supported by the chain-link-type transport element such that the counter reflector moves in an axial direction and/or a radial direction relative to a longitudinal axis of the respective one of the preforms held by the holding apparatus from a first position to a second position, which is different than the first position, as the transport chain is guided on the revolving chain path.
2. The apparatus according to claim 1, wherein the counter reflector is movably supported in a slidably guided manner in the axial direction and/or the radial direction by a guide pin provided on the chain-link-type transport element.
3. The apparatus according to claim 1, wherein the counter reflector is constrained by a spring force in the first position and is deflectable against the spring force into the second position.
4. The apparatus according to claim 3, wherein the first position is a heating position in which the counter reflector and the respective one of the preforms held by the holding apparatus are transported together through the heating section.
5. The apparatus according to claim 1, further comprising a cam control with a stationary control cam and a cam roller, wherein the cam control is configured and arranged such that movement of the counter reflector is carried out in the axial direction and/or in the radial direction in a loading area of the blow molding machine that precedes the heating section.
6. The apparatus according to claim 1, wherein each of the plurality of chain-link-type transport elements further comprises a mouth reflector for shielding a mouth section of the respective one of the preforms held by the holding apparatus from heating radiation from the plurality of heating devices.
7. The apparatus according to claim 6, wherein the mouth reflector is configured in a shape of a U that opens outward toward the mouth section of the respective one of the preforms held by the holding apparatus.
8. The apparatus according to claim 6, wherein the mouth reflector is arranged on the counter reflector and comprises a part of the counter reflector.
9. The apparatus according to claim 1, wherein the counter reflector is attached to the chain-link-type transport element by screws.
10. The apparatus according to claim 1, wherein the counter reflector is fastened to the chain-link-type transport element.
11. The apparatus according to claim 1, wherein the counter reflector is fastened to the holding apparatus.
12. The apparatus according to claim 5, wherein the cam control is configured and arranged so that the movement of the counter reflector is carried out in the axial and/or in the radial direction in an area of a reversal of the revolving chain path.
13. The apparatus according to claim 6, wherein the mouth reflector is configured to be slidable inward in the radial direction for replacement.
14. The apparatus according to claim 9, wherein the counter reflector is attached to the chain-link-type transport element by screws that are actuatable without use of a tool.
Description
(1) In the drawings, embodiments of the invention are represented diagrammatically.
(2) FIG. 1 shows a perspective representation of a blowing station for producing containers from preforms,
(3) FIG. 2 shows a longitudinal section through a blowing mold in which a preform is stretched and expanded,
(4) FIG. 3 shows a sketch for illustrating a basic construction of an apparatus for blow molding containers,
(5) FIG. 4 shows a modified heating section with increased heating capacity,
(6) FIG. 5 shows a side view of a holding apparatus from the prior art,
(7) FIG. 6 shows a vertical section according to cutting line VI in FIG. 5,
(8) FIG. 7a, 7b show perspective views of a transport and handling means with counter reflectors fastened thereto, in a first and a second counter reflector position,
(9) FIG. 8 shows a longitudinal section through a heating device, a transport mandrel and a counter reflector in the area of the heating section through which a preform and the counter reflector travel jointly,
(10) FIGS. 9a, 9b and 9c show perspective views of a transport and handling means with counter reflector fastened thereto in a second embodiment variant in a first counter reflector position and in a second counter reflector position which is shifted in radial direction relative to said first counter reflector position,
(11) FIGS. 10a, 10b and 10c show perspective views of a transport and handling means according to the invention with a counter reflector with an opening reflector, which is fastened to said transport and handling means.
(12) The basic construction of an apparatus for shaping preforms (1) to containers (2) is represented in FIG. 1 and in FIG. 2. The arrangement can here occur as represented or in a vertical plane rotated by 180.
(13) The apparatus for forming the container (2) consists substantially of a blowing station (3), which is provided with a blowing mold (4) into which a preform (1) can be inserted. The preform (1) can be an injection molded part made of polyethylene terephthalate. To enable an insertion of the preform (1) into the blowing mold (4) and to enable a removal of the finished container (2), the blowing mold (4) consists of mold halves (5, 6) and a bottom part (7) which can be positioned by a lifting apparatus (8). The preform (1) can be attached in the area of the blowing station (3) by a holding element (9). This holding element (9) can be configured, for example, according to the invention or as is known from the prior art. It is possible, for example, to insert the preform (1) by means of grippers or other holding apparatus directly into the blowing form (4). To enable a pressurized-air supply, a connecting piston (10) is arranged beneath the blowing mold (4), which supplies pressurized air to the preform (1) and at the same time produces a seal. However, in a modified construction, it is in principle also possible to use fixed pressurized-air feed lines.
(14) A stretching of the preform (1) occurs in this embodiment example by means of a stretching rod (11) which is positioned by a cylinder (12). According to another embodiment, a mechanical positioning of the stretching rod (11) is carried out via cam segments on which gripping rollers act. The use of cam segments is particularly advantageous if several blowing stations (3) are arranged on a rotating blowing wheel (25).
(15) In the embodiment represented in FIG. 1, the stretching system is designed so that a tandem arrangement of two cylinders (12) is provided. By means of a primary cylinder (13), the stretching rod (11) is first moved, before the start of the stretching process itself, into the area of a bottom (14) of the preform (1). During the stretching process itself, the primary cylinder (13) with extended stretching rod is positioned together with a carriage (15) supporting the primary cylinder (13) by means of a secondary cylinder (16) or via a cam control. In particular, it has been thought of to use the second cylinders (16) in a cam-controlled manner so that a current stretching position can be predetermined by a guide roller (17), which slides along a cam track during the performance of the stretching process. The guide roller (17) is pressed by the secondary cylinder (16) against the guide track. The carriage (15) slides along two guide elements (18).
(16) After the closing of the mold halves (5, 6) arranged in the area of supports (19, 20), a locking of the supports (19, 20) relative to one another occurs by means of a locking device (40). For the adaptation to different shapes of a mouth section (21) of the preform (1), the use of separate threaded inserts (22) in the area of the blowing mold (4) is provided according to FIG. 2.
(17) In addition to the blow molded container (2), FIG. 2 also shows the preform (1) drawn with a broken line, as well as, diagrammatically, a forming container bubble (23).
(18) FIG. 3 shows the basic construction of a blowing machine which is provided with a heating section (24) as well as with a rotating blowing wheel (25). Starting with a preform introduction (26), the preforms (1) are transported by transfer wheels (27, 28, 29) into the area of the heating section (24). Along the heating section (24), heat radiators (30) are arranged as heating devices, as well as blowers (31) in order to adjust the temperature of the preforms (1). After a sufficient temperature adjustment of the preforms (1), the latter are transferred by a transfer wheel (35) to the blowing wheel (25) in the area of which the blowing stations (3) are arranged. The finished blow-molded containers (2) are supplied by additional transfer wheels (37, 28, 38) to an output section (32). The transfer wheel (37) here is configured as a removal wheel and the transfer wheel (38) as an output wheel.
(19) In order to be able to shape a preform (1) to form a container (2) in such a manner that the container (2) has material properties that ensure a long usability of food items, in particular drinks, that have been filled into the container (2), special process steps must be complied with during the heating and orientation of the preforms (1). In addition, advantageous effects can be achieved by complying with special dimensioning requirements. As thermoplastic material, various plastics can be used. For example, PET, PEN or PP can be used.
(20) The expansion of the preform (1) during the orientation process occurs by pressurized-air supply. The pressurized-air supply is divided into a preblowing phase in which gas, for example, pressurized air, is supplied at a low pressure level, and a subsequent main blowing phase in which the gas is supplied at a higher pressure level. Typically, during the preblowing phase, pressurized air at a pressure in the range from 10 bar to 25 bar is used, and during the main blowing phase, pressurized air at a pressure in the range from 25 bar to 40 bar is supplied.
(21) In FIG. 3 one can also see that, in the represented embodiment, the heating section (24) is part of the transport path of the preforms (1). The transport of the preforms (1) occurs in the heating apparatus (300) by means of a plurality of revolving transport elements (33) which are arranged in a row in a chain-like manner and guided along reversing wheels (34, 36). The revolving transport elements (33) thus move along a chain path (301) which also forms the transport path of the preforms, since the preforms (1) are guided along the chain path (301). In particular, it has been thought to stretch to a substantially rectangular basic contour by means of the chain-like arrangement of the transport elements (33). In the represented embodiment, in the area of the expansion of the heating section (24) facing the transfer wheel (27), a single reversing wheel (34) of relatively large dimension is used, and, in the area of adjacent reversals, two reversing wheels (36) of relatively smaller dimension are used. However, in principle any desired other guides are also conceivable.
(22) To enable an arrangement of the transfer wheel (27) and of the blowing wheel (25) relative to one another that is as dense as possible, the represented arrangement has been found to be particularly advantageous, since, in the area of the corresponding expansion of the transport path (301), three reversing wheels (34, 36) are positioned, that is to say, in each case, the smaller reversing wheels (36) are positioned in the area of the transition to the linear courses of the transport path (301), and the larger reversing Wheel (34) is positioned in the immediate transfer area to the transfer wheel (27) and to the blowing wheel (25). Alternatively to the use of chain-like transport elements (33), it is also possible to use a rotating heating wheel, for example.
(23) After the blow molding of the containers (2) has been completed, said containers are moved out of the area of the blowing stations (3) by the transfer wheel (38) and transported to the output section (32).
(24) In the modified heating apparatus (300) represented in FIG. 4, it is possible, due to the larger number of heating radiators (30), to adjust the temperature of a larger number of preforms (1) per unit of time. The blowers (31) here lead cooling air into the area of cooling air channels (39), which are opposite from the associated heating radiators (30) in each case and deliver the cooling air via outflow openings. Due to the arrangement of the outflow directions, a flow direction is achieved for the cooling air that is substantially transverse to a transport direction of the preforms (1). In the area of surfaces opposite from the heating radiators (30), the cooling air channels (39) can provide counter reflectors for the heat radiation; it is also possible to implement a cooling of the heating radiators (30) via the delivered cooling air.
(25) A transport of the preforms (1) and of the containers (2) through the blowing machine (100) can occur in different ways. According to an embodiment variant, the preforms are supported at least along the substantial portion of the transport path thereof by transport mandrels. However, it is also possible to carry out a transport of the preforms using grippers that grip the preform on the outside, or to use internal mandrels that are introduced into a mouth area of the preform. In the same way, it is conceivable to use different variants in terms of the spatial orientation of the preforms.
(26) According to a variant, the preform is supplied in the area of the preform inlet (26) with the mouth thereof oriented in vertical direction upward, then conveyed along the heating section (24) and the blowing wheel (25) in a state in which it is rotated and with the mouth thereof oriented in vertical direction downward, and rotated again before reaching the output section (32). According to another variant, the preform (2) is heated in the area of the heating section (24) with the mouth thereof oriented in vertical direction downward, but rotated again by 180 before reaching the blowing wheel (25).
(27) According to a third embodiment variant, the preform runs through the entire area of the blowing machine (100) without undergoing any reversing processes, with the mouth thereof oriented in vertical direction upward.
(28) FIG. 5 shows a partial representation of a side view of a preform (1) in the mouth section (21) thereof, in some areas, a holding apparatus (41) known from the prior art is introduced. This holding apparatus (41), together with the transport element (33), is an example of a transport and handling means in the sense of the claims. In the diagrammatic FIGS. 3 and 4, in each case, only the reference number 33 is indicated for the transport elements connected in a chain-like manner.
(29) The holding apparatus (41) shown as an example comprises an element base (42), a head (43) facing the preform (1), as well as a shaft (44) connected to the head (43). The shaft (44) with the head (43) is movable relative to the element base (42) in direction of an element longitudinal axis (45). A base position of the shaft (44) relative to the element base (42) can be predetermined by a spring (46). In the represented embodiment example, the spring (46) is arranged between upper side (47) of the element base (42) and an end segment (48) protruding over the shaft (44).
(30) According to a typical embodiment example, a plurality of element bases (42) can be connected to one another in a chain-like manner or connected to a revolving transport chain. This results in an arrangement as shown in FIGS. 3 and 4. However, the holding apparatus (41) can also be attached to revolving transfer wheels or other devices. According to a typical embodiment, a positioning of the shaft (44) relative to the element bases (42) occurs likewise in a cam-controlled manner via a cam that extends at least in some sections along a transport path of the holding apparatus (41).
(31) FIG. 6 shows in a longitudinal section the positioning of the head (43) within a mouth section (21) of a preform (1) or of a container (2). One can see that the head (43) comprises recesses (49) in which clamping elements (50) are arranged. Outside of the area that can be introduced into the mouth section (21), the head (43) can comprise a cooling body (51), which is provided with cooling ribs for the heat radiation.
(32) FIGS. 7a and 7b show a first embodiment example for a transport and holding means (33, 41) configured according to the invention, with a counter reflector (60) attached thereto. FIG. 7a shows the counter reflector (60) in a lowered position, while FIG. 7b shows the base position of the counter reflector (60). This base position is held spring-loaded, wherein this spring, in a manner that is not represented, is located inside the counter reflector (60), and exerts a spring force against a lowering movement of the counter reflector (60).
(33) The transport and handling means (33, 41) according to the invention and represented as an embodiment example consists of a transport element (33) as well as a holding apparatus (41) supported thereby, as described above in reference to FIGS. 5 and 6 as an example. In addition, the represented transport and handling means (33, 41) comprises a counter reflector (60) slidably mounted on the transport element (33) in axial direction. This counter reflector (60) has, on the side thereof that faces a preform, a recess (65) with inner contour the shape of which is adapted to the preform (1). The preform (1) represented is partially received by the recess (65) and enclosed, in reference in FIG. 8, partially cylindrically and preferably largely equidistantly. On an outer side facing away from the preform, for example, a control roller (69) is arranged, which cooperates with an external control cam that is not represented.
(34) The counter reflector (60) is guided on guide pins (70) in axial direction. These guide pins (70) are stationarily fastened to the transport element (33) and extend from the transport element (33) in vertical direction downward. The counter reflector (60) comprises guide bores that are not visible in the selected representation. The guide pins (70) extend in these guide boreholes. The counter reflector (60) is secured against falling down in vertical direction by quick-fastening screws (71) which, in the base position shown in FIG. 7b, protrude on the bottom side over the counter reflector (60) and can be loosened without tool for the purpose of replacing the counter reflector (60), for example.
(35) The holding apparatus (41), in FIGS. 7a and 7b, is implemented as a transport mandrel, as it is described, for example, in reference to FIGS. 5 and 6. In the position of this transport mandrel shown in FIG. 7a, the head (43) is immersed in the mouth section (21) of the preform (1). The preform (1) is located in a lowered position beneath the mouth reflector (72). In FIG. 7b, the preform (1) and the transport mandrel supporting the preform (1) is in a raised position in which the mouth section (21) of the preform (1) is lifted until the mouth reflector (72) shields the mouth section (21) against heat radiation, as can be seen in FIG. 8 in a cross-sectional representation.
(36) In the positioning of the counter reflector (60), represented in FIG. 7a, which is predetermined by the external control cam, the preform (1) receives freedom of movement in vertical direction so as to assume the positioning represented in FIG. 7a, which, for example, corresponds to the transfer position of a transfer wheel. The represented positioning of the counter reflector (60) and of the preform (1) is thus assumed, for example, in the area of the transfer wheel (29) of FIG. 3. In the area of the removal wheel (35) as well, a positioning of counter reflector (60) and preform (1), as represented in FIG. 7a, is assumed, while the positioning represented in FIG. 7b is assumed at the time of the passage through the heating section (24). This positioning is also represented in the cross-sectional representation of FIG. 8, in which a passage through a heating box occurs.
(37) FIG. 8 shows a cross section in the area of the heat radiator (30) through a transport and handling means (33, 41) with a traveling counter reflector (60). In the represented embodiment example, the counter reflector (60) assumes the heating position shown in FIG. 7b, that is to say the counter reflector (60) is in a positioning close to the preform, that is to say at a small distance from the preform (1). The counter reflector (60) is fastened to the transport element (33). The transport element (33) in addition supports the holding apparatus (41) which can be configured, for example, in the manner explained in reference to FIGS. 5 and 6. As to the heating device (30), only one heating element (66) is shown, wherein, as a rule, in the area of the heating section (24) several heating elements (66) are arranged in vertical direction one above the other. These additional heating elements would thus be arranged distributed beneath the represented heating element (66) over the height extent of the preform (1).
(38) In FIG. 8, one can see that the traveling counter reflector (60) comprises, facing the preform, an inner contour (65) which is adapted in shape in order to enclose the preform (1) as equidistantly as possible over the reflector-facing partial circumferential area thereof at a small distance. In this manner, the heat radiation emitted by the heating element (66) can be reflected efficiently and turned back onto the preform (1). Since, as can be seen, for example, from FIG. 7a, the traveling counter reflector (60) is moved away from the transport element (33), for example, in the reversal areas of the chain path (301), and, for example, in a cam-controlled manner, freedom of movement exists nevertheless for the preform (1) toward and away from the transport element (33) and toward and away from the holding apparatus (41) supported thereby, as required typically for plugging on and removing processes, for example, in the interaction with grippers or transfer wheels known in the prior art. In particular, a height-wise movement of the transport element (33) or of the holding apparatus (41) can be carried out, without colliding with the counter reflector (60).
(39) FIGS. 9a, 9b and 9c show, in perspective views, inventive transport and handling means (33, 41) with counter reflector (60) attached thereto according to a second embodiment variant. While, according to the embodiment variant of FIGS. 7a and 7b, a movement of the counter reflector (60) occurred relative to the transport element (33) in vertical direction or in axial direction of the preform (1), according to the embodiment example of FIGS. 9a to 9c, a relative movement occurs between the counter reflector (60) and the transport element (33) in a radial direction away from the preform (1). Below, only changes in comparison to the embodiment of FIGS. 7a and 7b are to be described.
(40) FIG. 9c shows a partial detail of the transport chain (301) shown, for example, in FIG. 3 that is to say in a reversal area, in particular in the area of the transfer wheel (35) or of the inlet wheel (29). Accordingly, the transport chain (301) assembled from several transport elements (33) has a curved course. Due to this curved course, there are gaps between adjacent counter reflectors (60). In the positioning of the counter reflectors (60) represented in FIG. 9c, these gaps barely remain visible, since the counter reflectors (60) have been shifted radially inward. The gaps between the transport elements (33) above the counter reflectors (60) supported by said transport elements can be seen better.
(41) In the positioning represented in FIG. 9a, the counter reflector (60) assumes the base position thereof in which it is held applied by spring force. This spring force is applied by a spring (74) which is arranged coil-shaped on radially inward pointing guide pin (70). The guide pins (70) are located on the side of the transport element (33), which faces away from the preform, and they extend in radial direction up to a guide element (75) of the counter reflector (60). This guide element (75) has guide boreholes into which the guide pins (70) engage. A quick-fastening screw (71) ensures that the counter reflector (60) is slidably held on the guide pins (70). The guide element (75) moreover comprises a control roller (69) which cooperates with an external control cam, which is not represented, in a manner known from the prior art.
(42) In the positioning represented in FIG. 9a, the counter reflector (60) encloses the preform (1) with small spacing. The preform (1) is shown in a raised positioning, i.e., the mouth area (21) is shielded by the mouth reflector (72) against heat radiation.
(43) In the positioning represented in FIG. 9b, the counter reflector (60) is slid in a cam-controlled manner from the base position thereof in radial direction, so that the preform (1) can be lowered in the represented manner. It is now possible, for example, to transfer the preform (1) to a transfer wheel (29, 35).
(44) The positioning represented in FIG. 9b is also assumed in FIG. 9c and corresponds, for example, to the positioning desired in the area of the transfer wheels (35, 29). In comparison, the positioning represented in FIG. 9a corresponds to the arrangement of counter reflector (60) and preform (1), which is desired in the area of the heating section (24).
(45) FIGS. 10a to 10c show perspective views of a third embodiment of the invention. Here too, only the changes present in comparison to FIGS. 7 to 9 are described.
(46) The counter reflector (60) is stationarily connected in this depicted embodiment example to the transport element (33). In order to enable nevertheless a removal or a loading process of the preforms (1), the mouth reflector (72) is configured in a special way. This mouth reflector (72) is arranged on the counter reflector (60) and it has an open U-profile in preform direction. As a result, the preform (1) can be moved in direction toward the counter reflector (60), until a desired positioning is reached. For example, the mouth reflector (72) can be dimensioned so that the preform (1) with the neck ring thereof can bear in a bracing manner against said mouth reflector. FIG. 10a indicates how the preform (1) can be moved in direction toward the counter reflector (60). This occurs, for example, in the area of the transfer wheels (35, 29), for example, supported by grippers or other holding apparatus.
(47) The positioning shown in FIG. 10b is assumed when the transfer to the transport and handling means (33, 41) is partially completed. The neck ring of the preform (1) bears against the mouth reflector (72). However, the head (43) of the holding apparatus (41) is not yet lowered. This occurs only in the transition to the positioning shown in FIG. 10c. The head (43) is located in this positioning in the mouth section (21) of the preform (1) and can now clampingly support said preform.
(48) The positioning represented in FIG. 10c corresponds here to the desired positioning in the area of the heating section (24). The mouth reflector (72) can be completed, for example, in the area of the heating section (24) by an additional mouth reflector element arranged stationarily there to form a largely closed mouth reflector. By comparison, FIGS. 10a and 10b show the positioning in the transfer area of the transport path (301) of the preforms (1).
(49) In the represented embodiment, the mouth reflector (72) is configured to form a single part with the counter reflector (60). However, it can also be implemented as a separate element and fastened to the counter reflector (60). This can also be implemented in a different way, for example, in that the mouth reflector (72) is slidably mounted in radial direction in a direction facing away from the preform. This can occur, for example, against a spring force which presses the mouth reflector (72) into a desired positioning. Such a slidability can be appropriate, particularly if otherwise there is a risk of collisions with other holding apparatus in the transfer area.
(50) FIGS. 7 and 9 show a movability of the counter reflector (60) relative to the transport element (33) in radial or in vertical direction. Mixed forms of these two separately shown movement directions are also conceivable. However, the movement patterns shown are found to be particularly simple and therefore are considered to be preferred relative movements.
(51) It is also conceivable to combine the relative movement, explained in reference to FIGS. 7-9, between transport element (33) and counter reflector (60) and to combine the special embodiments of the mouth reflector (72), which are represented using FIGS. 10a to 10c.
