EP2507033A2

EP2507033A2 - Furnace for conditioning preforms

Info

Publication number: EP2507033A2
Application number: EP10772981A
Authority: EP
Inventors: Frank Winzinger; Christian Holzer; Wolfgang Schönberger; Konrad Senn; Andreas Wutz
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2009-12-04
Filing date: 2010-10-20
Publication date: 2012-10-10
Also published as: DE102009047540A1; US20120269918A1; WO2011066885A3; WO2011066885A2; CN102725124A

Abstract

The invention relates to a furnace for conditioning preforms, comprising a heating wheel, on which several heating chambers for heating one preform each are arranged. The preforms can be heated independently of each other in a flexible and energy-efficient manner in that the walls of the heating chambers, in particular the bottom wall of the heating chambers that lies opposite the hole for inserting the preforms and the side wall adjacent thereto comprise an insulating layer in order to thermally insulate the heating chambers of the heating modules.

Description

Furnace for conditioning preforms

The invention relates to a rotary type kiln for conditioning preforms according to the preamble of claim 1.

Containers to be produced in the blow-molding or stretch blow molding process are formed from so-called preforms or preforms, which must be heated to a desired process temperature before the actual blowing process. In order to transform the rotationally symmetrical preforms, which generally have standardized wall thicknesses, when blowing into containers having a specific shape and wall thickness, individual wall areas of the preform are to be heated in a metered manner, preferably with infrared radiation. For this purpose, usually a continuous stream of preforms is passed through a furnace with appropriately adapted irradiation sections. A problem of such ovens, however, is to introduce as much of the radiated heat output as possible in the preforms.

As an alternative to this, the published patent application DE 10 2006 015853 A1 proposes to heat preforms into individual irradiation chambers surrounding the preforms in each case circumferentially, wherein the individual chambers are arranged in the form of a carousel. In this case, each preform is heated both by the inner wall of the chamber designed as a ceramic infrared radiator and by a rod-shaped infrared radiator introduced into the preform. As can be seen from a schematic representation of DE 10 2006 015853 A1, the preform is introduced completely into the irradiation chamber. However, it remains unclear how the temperature distribution in the individual chambers can be influenced flexibly and as independently as possible, and how the heat output delivered in the chamber can be used as effectively as possible for heating the preform.

Although the heating chambers of DE 10 2006 015853 A1 are predominantly thermally insulated radially outwards, they are in direct contact with each other, so that heat equalization between the heating chambers is possible. In addition, the chambers are open at the top, so that heat can escape unused and uncontrolled. However, it is desirable to control various circumferential and radial temperature profiles in the heating elements in a controlled and energy efficient manner. Thus, there is a need for a single chamber oven improved in this regard. It is the object of the invention to provide an oven in which the heating chambers can be adapted in the most flexible manner and independently of one another to a desired temperature profiling of the preforms, both in circumferential as well as in axial alignment, and in which heat losses are minimized.

This is achieved with a furnace comprising the features defined in the characterizing part of claim 1. By virtue of the fact that the walls of the heating chamber, in particular a bottom wall of the heating chamber opposite to a recess for introducing the preform, and the adjacent side wall of the heating chamber comprise an insulating layer, the circumferential and axial heating profiles of the individual heating chambers can be flexibly and independently adapted to the respective requirement become. In addition, heat losses are reduced.

Materials suitable for the insulating layer are preferably plastics, in particular PET, polyethylene, polystyrene, Neopor or polyurethane, but also aluminum, in particular layered aluminum, ceramics, mineral bevels such as glass or rock wool, ceramic film in a layer composite with other materials, wood or cork. Other conceivable materials would be composite pulp systems, hemp, flax, coconut or reed slabs. Mineral foams such as aerated concrete, pumice, (Prelite) expanded clay, expanded mica, calcium silicate or foam glass can also be used. Also conceivable would be composite layers comprising any selection from the materials mentioned.

Preferably, a lid is provided on the recess of the heating chamber in order to close the heating chamber thermally insulating in the unpopulated state. This minimizes temperature fluctuations in the heating chamber and further reduces thermal losses.

In a preferred embodiment, the holding device comprises at least one gripping element, which can be cooled by a liquid and / or air flow, for holding and cooling a mouth region of the preform during the irradiation. This can ensure that the mouth region, which should remain unchanged during the blowing process, is not heated inadmissibly, so that sufficient stability of the mouth region during the irradiation and the subsequent blowing process is ensured.

Preferably, at least one ventilation inlet for the eccentric injection of cooling air into the preform is provided on the holding device in order to convey the injected cooling air substantially along the inside of the preform wall. This can avoid that the inside of the preform is heated disproportionately compared to a central wall portion or the outside of the preform. In a preferred embodiment, at least one ventilation inlet for introducing a cooling air flow and a ventilation outlet for discharging the air flow are provided on the heating chamber in order to convey cooling air along the outside of the preform wall. This makes it possible to prevent the outside of the preform from becoming disproportionately heated compared to a central wall region or the inside of the preform.

Preferably, the heating chamber and the holding device are rotatably mounted to each other to swirl the cooling air flow in the heating chamber and / or helically along the preform. As a result, the surface of the preform can be uniformly cooled circumferentially.

In a preferred embodiment, at least one temperature sensor for determining an internal temperature is provided in the heating chamber, the oven further comprising a control unit for setting an infrared heating power and / or a cooling air flow in the heating chamber on the basis of the determined internal temperature. Thereby, a timing of the heating of the preform can be set in the heating chamber and / or a certain temperature level can be maintained in the heating chamber.

A preferred embodiment of the invention further comprises air guiding devices, which are inclined and / or curved against a direction of rotation of the heating wheel, in order to guide air accumulated by rotation of the heating wheel against the heating chambers. As a result, a cooling air flow can be realized without the use of an additional blower. The course of the air flow can also be controlled by targeted shaping of the louvers.

Preferably, the heating chamber comprises at least one radiant heater in the form of a heating coil embedded in a ceramic layer, the ceramic layer being adapted for emission in the range from 2 to 3.5 μm. By the ceramic layer, a larger and more uniform radiating surface compared to the heating coil can be provided and the spectral range of the radiated heat radiation and its spatial distribution can be adapted to produce a desired temperature distribution in the preform. In the wavelength range of 2 to 3.5 μηη a particularly large proportion of the radiated heat radiation is absorbed in the preform, so that the heating can be particularly well focused on a specific wall area.

In a particularly advantageous embodiment, the heating chamber comprises at least one radiant heater in the form of a light radiator with a maximum radiation at a wavelength of less than 2 μηη, in particular a bright radiating halogen radiator, a bright light emitting diode and / or a bright-emitting laser. Such radiators can be based on low inertia control time particularly accurate and allow adaptation of the irradiation spectrum to different preform materials and material thicknesses. Due to the comparatively low absorption in the wall of the preform, the light radiation can excite a passive radiator arranged on the rear side of the irradiated wall.

Preferably, the heating modules further each comprise a heating rod for irradiating an inner wall portion of the preform with infrared radiation, the apparatus being further adapted to raise and lower the holding device and / or the heating rod to insert and withdraw the heating rod into the preform. With the additional heating rod, the wall of the preform can be uniformly irradiated and heated over its entire thickness. In addition, wall areas can thereby be irradiated, in particular in the vicinity of the mouth region of the preform, which can only be irradiated inadequately by the outer radiant heater. The lifting device also facilitates the axial profiling of the preform by targeted irradiation of axial areas of the preform.

In a preferred embodiment, the heating modules further comprise a thermally insulating housing for the heating element, in which the heating element can be withdrawn, wherein on the housing in particular a lid is provided to close the housing with retracted heating rod thermally insulating. As a result, heat losses can be minimized with withdrawn heating element. In addition, it is possible to reduce temperature fluctuations of the heating element.

Preferably, a plurality of radiators with different and / or separately adjustable heating power are provided on the heating rod in the longitudinal direction. Thus, an axial thermal profiling of the preform wall, in particular on the inside, be facilitated by selective activation of the individual radiator. In addition, a temporal variation of the axial profiling is possible without moving the heating element in the preform.

Preferably, at least one ceramic layer for emitting infrared light is provided on the heating element, in particular by converting bright radiation having a radiation maximum at a wavelength of less than 2 μητι into a longer wavelength radiation having a wavelength in the range from 2 to 3.5 μηη. This makes it possible to operate the heating element completely or additionally passive by acting from the outside of the preform radiant radiation through the wall acts on the heating element and is converted by this into radiation which is particularly effective for heating the inside of the preform. In a particularly favorable embodiment, a radiation shield which can be cooled by a liquid and / or air stream is provided on the heating element and / or the holding device in order to shield and / or cool the mouth region with respect to the infrared radiation emitted by the heating element. As a result, excessive heating of the mouth region can be avoided, in particular to ensure stable retention of the preform in the heating chamber and stable shaping of the mouth region during the blowing process.

In a preferred embodiment, the heating chambers are thermally insulated from each other.

In a further preferred embodiment, the heating chambers are thermally insulated only to the outside and communicate with each other in heat exchanging contact.

In a further preferred embodiment, the mouth regions of the preform are cooled directly with an air flow. This can be formed by a fan inside or outside the furnace and routed via lines to the areas to be cooled.

In a further preferred embodiment, the heating chambers are each cooled by a separate fan.

In an alternative embodiment, the preforms are not suspended but taken up in the vertical direction with the mouth region down in the heating chamber.

Preferred embodiments of the invention are shown in the drawing. Show it:

Figure 1 is a schematic plan view of a furnace according to the invention with circumferentially uniformly distributed heating chambers.

2 shows a schematic longitudinal section through a heating chamber of a first embodiment with a central heating element introduced into a preform;

Fig. 3a

and FIG. 3b shows schematic longitudinal sections through variants of the heating chamber;

4 shows a schematic longitudinal section through an alternative embodiment of the heating chamber according to the invention with a movable shielding;

5 shows a schematic longitudinal section through an alternative variant of the heating chamber with a cooled gripper; Fig. 6a

and FIG. 6b show schematic longitudinal sections through alternative embodiments of the heating chamber according to the invention with a cooling function for the outer wall of the heated preform;

7 is a schematic representation of air cooling for the heated by a heating mandrel interior of the preform.

Fig. 8 is a plan view of an embodiment of the furnace with Luftleitvorrichtungen for

Cooling the outer wall of the heating chambers; and

9 shows a schematic longitudinal section through a heating chamber with temperature sensors.

As can be seen Fig. 1, the furnace 1 according to the invention is designed as a rotary and comprises a rotatably mounted heating wheel 2, on the circumferentially evenly distributed heating modules 3 are arranged, the number of which can differ from the example shown and each have a heating chamber 4 for heating each comprise a preform 5 and a holding device 7 for holding the preform 5, wherein the holding device 7 can be moved via a lifting device 9 at least in the axial direction with respect to the longitudinal axis 5 'of the preform 5. The holding devices 7 and the lifting devices 9 are set up so that they each can take over a preform 5 from a conventional inlet starwheel (not shown) and lower it into the heating chamber 4. Furthermore, the heated preform 5 can be transferred from the holding device 7 and the lifting device 9 to a conventional outlet star (not shown) for further processing of the preform 5.

As FIG. 2 shows, an insulation layer 10 is provided on the heating chambers 4 in each case. The insulating layer 10 surrounds the heating chamber 4, preferably with the exception of an opening 4a of the heating chamber for introducing the preform 5 into the heating chamber 4. In particular, the heating chamber 4 is completely enclosed by the insulating layer 10 with respect to the main axis 5 'of the preform 5 to be introduced. As a result, a heat exchange between the heating chambers 4 of the individual heating modules 3 is largely avoided.

In the heating chamber 4, at least one heating element 11 is further provided for irradiating the outside 5a of the preform 5. FIG. 2 also shows an optional heating rod 13, which can be lowered into the preform 5 via the lifting device 9. At least one heating element or emitter 15 is provided on the heating rod 13 for irradiating the inner side 5b of the preform 5, wherein the emitters 15 (in the example eight pieces) are preferably provided separately. are controllable. The holding device 7 is not shown in FIG. 2 for the sake of clarity. In Fig. 2, a sleeve-shaped shielding member 17 is further indicated, which surrounds the heating element 13 in an annular shape, and which shields an opening region 5c of the preform 5 relative to the heating element 13 optically and thermally. For this purpose, the shielding element 17 can be cooled by an air flow or a liquid.

Figs. 3a and 3b show different variants of the heating elements 11 and 15, which can be combined with each other depending on the embodiment. The insulation layer 10 is only indicated for the sake of clarity.

In Fig. 3a, for example, a plurality of heating elements 11 of the heating chamber 4 are formed as axially stacked, annular functional ceramics. These are preferably each actively heated with a wire helix (not shown). The heating elements 11 preferably radiate in the wavelength range of 2 to 3.5 μηι.

On the heating rod 13 of Fig. 3a, a radiator or heating element 15 is also in the form of a functional ceramic with active heating by a wire coil (not shown) is formed. The preferred spectral range is also for the heating element 15 of the heating element 13 between 2 and 3.5 μηη. On the heating element 13, however, a plurality of annular heating elements 15 could be stacked in the axial direction one above the other.

In contrast, in the variant of FIG. 3b, a heating element 15 in the form of a passive functional ceramic is provided on the heating rod 13. Passive means in this context that the heating element 15 is not provided with its own power supply, but in the heating chamber 4 radiated heat radiation either reflected and / or converted into a heat radiation with a longer wavelength. This is particularly advantageous if at least one of the heating elements 11 is designed as a light radiator whose radiation is absorbed comparatively weakly in the wall 5d of the preform 5, so that the heating element 15 can also be effectively irradiated with light radiation through the wall 5d. The radiation emitted by the passive radiator 15 then preferably has a greater wavelength and is absorbed comparatively strongly in the wall 5 d of the preform 5.

Also indicated in FIG. 3b are various variants of the radiators 11, for example light radiators 11a in the form of halogen radiators, a light-emitting diode 11b, which are each characterized in that they have a radiation maximum at a wavelength of less than 2 μm. Alternatively, a laser would be suitable as a light radiator. Also indicated is a second functional ceramic 11c, which may be designed, for example, as a passive functional ceramic for converting an irradiated wavelength into a longer-wave thermal radiation can, and a heated with a heating coil, active functional ceramic 11d with a specially adapted spectral radiation behavior. The various variants of the radiant heater 1 1 can be combined in any way with each other to heat circumferential or axial portions of the preform 5 with selected beam characteristics.

Shown in FIGS. 3 a and 3 b is the shielding element 17, with which the mouth region 5 c of the preform 5 is protected against excessive irradiation. The inside of the heating chamber wall 4b, 4c is preferably provided with a heat radiation reflecting coating 19 at the locations where no radiant heaters 11 are provided.

The radiant heaters 11 and 15 could alternatively emit electromagnetic radiation in another wavelength range, for example microwave radiation, as an alternative to infrared radiation. Furthermore, the radiators are not limited to the rotationally symmetrical shapes shown. In particular, for circumferentially selective profiling of the preforms 5, the so-called preferred heating, different radiators 11, 15 may be formed only as circumferential segments, for example as ring segments.

4 shows a variant of the heating module 3, in which a cover 21 is provided on the heating chamber 4, with which the opening 4a of the unpopulated heating chamber 4 can be closed, as indicated on the right side of FIG. For comparison, the equipped with a preform 5 heating chamber 4 is shown on the left side of Fig. 4. The lid 21 is preferably designed so that it acts thermally insulating and heat radiation reflecting. In addition, a thermally insulating housing 23 is provided for the heating element 13, on which a cover 25 is formed, which can be closed at unpopulated heating chamber 4, so that the drawn back into the housing 23 heater 13 is thermally insulating and heat radiation is reflective protected against cooling ,

Preferably, an infrared radiation reflecting layer 19 is provided on the inner sides of the housing 23 and the lid 21 and 25. The covers 21 and 25 could be made in one piece and, for example, for closing the heating chamber 4 and the housing 23 are pivoted before this. But they can also be designed in several parts and, for example, as indicated in Fig. 4 by block arrows, are pushed apart or together. For simplicity, the associated operating mechanisms and the holder of the heating element 13 are not shown.

With such closures for the heating chambers 4 and the housing 23, a heating of the chambers 4 or of the heating elements 13 after the furnace 1 has been switched on could also be accelerated until an operating temperature is reached. In Fig. 5, a holding device 7 is shown with a cooled gripper 27 which surrounds the mouth region 5c of the preform 5 from the outside like a pincers. Alternatively, it would also be possible to form a gripper 27 on the holding device 7, which holds the mouth region 5c from the inside. As indicated in Fig. 5, the gripper 27 is preferably provided with cooling fins 28 in order to cool the gripper 27 by convection, in particular with air, from the outside. However, it would also be conceivable to have liquid cooling in which a cooling liquid flows through the gripper in a manner comparable to a cooling sleeve. The sleeve-shaped shielding element 17 is preferably also cooled, for example by a cooling liquid flow or an air flow.

A platen of the heating chamber 4 for a support ring 5e formed on the preform 5 may be formed as a cooled shield 29, the gripper 27 being capable of being thermally conductive contacted with the shield 29 (not shown) to grip the gripper 27 with the aid of the shield 29 to cool. In addition, the gripper 27 may be formed so that it is in thermally conductive contact with the sleeve-shaped shielding member 17, so that both the gripper 27 and the shielding member 17 can be cooled by means of the cooling shield 29. This is particularly advantageous in order to reduce the number of supply lines of cooling liquid and / or cooling air.

FIGS. 6 a and 6 b show variants of the heating chamber 4 with active cooling of the outside 5 a of the preform 5 by introducing a cooling air flow 14 symbolized in each case by arrows.

In the variant of FIG. 6a, the cooling air flow 14 is introduced through a recess 4d in the wall 4b of the heating chamber 4 from below. As can also be seen in FIG. 6 a, the cooling air flow 14 is guided essentially along the surface 5 a of the preform 5 and escapes from the heating chamber 4 through recesses 4 e, which are provided, for example, on a support plate 4 f for the support ring 5 e of the preform 5 can.

In the variant of FIG. 6b, a gap 11a is provided in each case between the heating elements 11, through which the cooling air flow 14 introduced from below can escape to the outside. In this case, the recesses 4e are preferably arranged so that the air flow 14 is conducted radially outside the heating elements 11 through the support plate 4f. Depending on the design of the cooling of the mouth region 5c of the preform 5, either the variant of FIG. 6a or the variant of FIG. 6b can be particularly advantageous. The cooling indicated in FIGS. 6a and 6b is advantageous if a superficial region of the wall 5d of the preform 5 is excessively heated by the action of heat radiation compared to a central wall region, in particular if long-wave infrared radiation is used, which is particularly well absorbed in the wall 5d. In order to distribute the cooling effect as evenly as possible on the surface 5a of the preform 5, it is advantageous to allow the preform 5 to rotate relative to the heating chamber 4. It would also be possible to introduce the cooling air flow 14 in such a way that it is guided around the preform 5 essentially following a helix. The direction of the cooling air flow 14 could also be reversed, ie, run from top to bottom in the drawings 6a and 6b.

FIG. 7 shows a variant in which the inside 5b of the preform 5 is actively cooled by a cooling air flow 14. The heating chamber 4 is not shown here for the sake of simplicity. As can be seen from FIG. 7, the cooling air flow 14 is introduced asymmetrically at a distance 14a to the main axis 5 'of the preform on one side of the heating element 13 from above into the preform 5 and guided along the heating rod 13 or the inner side 5b. As is also indicated in FIG. 7, the cooling air flow 14 is again discharged to the outside through the circumferentially opposite side of the preform 5. With the illustrated air cooling, the inner wall 5b of the preform 5 can be cooled to prevent excessive heating of a superficial portion of the wall 5d of the preform 5 by the action of heat radiation emanating from the heating rod 13 compared to a central wall portion. This may be advantageous in particular when exposed to long-wave infrared radiation.

In the arrangement shown in Fig. 7, it is advantageous if the preform 5 with respect to the heating element 13 and the cooling air supply 14b and the cooling air discharge 14c rotates. As a result, the cooling air flow 14, which is marked by arrows in FIG. 7, can be guided particularly uniformly along the wall 5b of the preform 5. In addition, in particular in the case of long preforms 5, it may be expedient to provide an additional suction at the cooling air discharge 14c for targeted discharge of the cooling air flow 14. This is not shown for the sake of simplicity.

Fig. 8 shows an embodiment of the furnace 1 according to the invention, in which the heating chambers 4 and the heating modules 3 are cooled by the supply of a cooling air flow 34 during the rotation of the heating wheel 2. For this purpose, air-guiding devices 31 are provided on the heating wheel 2, in each case associated with the heating modules 3, for example suitably shaped walls or channels, which can be designed in particular as air baffles. These are curved and / or inclined in the direction of rotation 2 a of the heating wheel 2, so that when the heating wheel 2 is pushed up, pent-up air is conducted as cooling air flow 34 through the louvers 31 in the direction of the heating modules 3. As indicated in FIG. 8, the air guiding devices 31 function in a manner comparable to paddle wheels, the cooling air 34 being conducted past the heating modules 3 and being discharged through a central collecting shaft 33. To the effect of the cooling air flow 34, cooling fins 35 may be formed on the heating chambers 4. Such cooling may be advantageous, although the heating chambers 4 are thermally insulated. Remaining residual heat can also be dissipated this way and kept away from thermally sensitive assemblies. In addition, the cooling air flow 34 can be used to cool the holding device 7, the gripper 27, the shield 17 and / or the mouth region 5c of the preform 5. Alternatively or in addition to the illustrated air cooling, it would also be possible to cool the heating chambers 4 with liquid cooling.

FIG. 9 shows a further variant of the heating chamber 4, in which temperature sensors 41 are additionally provided. These can be provided, for example, in the vicinity of the recesses 4d of the supply line 14b or on the discharge 14c of the cooling air 14. With the temperature sensors 41, it is possible to monitor the temperature within the heating chamber 4. Likewise, it is conceivable, with the aid of the temperature sensor 41 and a suitable control device, to regulate the amount of cooling air introduced into the heating chamber 5, in particular in the case of forced convection with a fan. However, this would also be possible with free convection. A temperature control can also be used to stabilize the heat distribution in the preform and / or to compensate for differences between individual heating chambers 4 or preforms 5. It would also be conceivable to readjust the amount of air to be introduced as a function of a measured final temperature after the preform has been heated and / or to mix discharged cooling air 14 for temperature regulation at least partially with cooling air 14 to be supplied and / or the discharged cooling air 14 to a heat exchanger for heat recovery to another process.

With the aid of temperature sensors 41, the temperature in the heating chambers 4, in particular after closing the lid 21, when the heating chamber 4 is not equipped, can be set constant or at a uniform starting temperature for heating the preforms 5.

The features of the described embodiments and variants can be combined as desired. In particular, different variants of irradiation, insulation and cooling can be combined with one another.

Claims

Patent claims

1. Oven of the rotary type for conditioning preforms (5), in particular for the stretch blow molding of plastic vessels, with a heating wheel (2) on which several heating modules (3) are arranged for heating one preform (5), the heating modules (3 ) each comprise a heating chamber (4) with at least one radiant heater (11) for irradiating an outer wall region (5a) of the preform (5) with infrared radiation, and wherein on the heating chamber (4) there is a recess (4a) for inserting the preform (5 ) is provided,

characterized in that

the heating modules (3) further include:

- a holding device (7) for holding the preform (5); and

- a lifting device (9) for raising and lowering the holding device (7) and/or the heating chamber (4) in order to move the preform (5) into or out of the heating chamber (4), the walls of the heating chamber (4 ), in particular the bottom wall of the heating chamber (4b) opposite the recess (4a) and the adjacent side wall (4c) of the heating chamber (4), comprise an insulation layer (10) in order to provide thermal insulation to the heating chambers (4) of the heating modules (3). to isolate.

2. Oven according to claim 1, characterized in that a cover (21) is provided on the recess (4a) of the heating chamber (4) in order to close the heating chamber (4) in a thermally insulating manner in the unequipped state.

3. Oven according to claim 1 or 2, characterized in that the holding device (7) has at least one gripping element (27) which can be cooled by a liquid and/or air flow (14) for holding and cooling a mouth region (5c) of the preform (5). during irradiation.

4. Furnace according to at least one of the preceding claims, characterized in that on the holding device (7) there is at least one ventilation inlet (14b) for the eccentric blower! of cooling air (14) is provided in the preform (5) in order to guide the blown-in cooling air (14) essentially along the inside (5b) of the preform wall (5d).

5. Oven according to at least one of the preceding claims, characterized in that at least one ventilation inlet (4d) for introducing a cooling air flow (14) and a ventilation outlet (4e) for discharging the air flow (14) are provided on the heating chamber (4). To direct cooling air along the outside (5a) of the preform wall (5d).

6. Oven according to claim 5, characterized in that the heating chamber (4) and the holding device (7) are mounted rotatably relative to one another in order to swirl the cooling air flow (14) in the heating chamber (4) and/or helically on the preform (5 ) to guide along.

7. Oven according to at least one of the preceding claims, characterized in that at least one temperature sensor (41) is provided in the heating chamber (4) for determining an internal temperature, and that the oven (1) further has a control unit for setting an infrared heating power and / or a cooling air flow (14) in the heating chamber (4) based on the determined internal temperature.

8. Oven according to at least one of the preceding claims, further characterized by air guiding devices (31) which are inclined and/or curved against a direction of rotation (2a) of the heating wheel (2) in order to move air accumulated by rotation of the heating wheel (2) against the heating chambers (4) to direct.

9. Furnace according to at least one of the preceding claims, characterized in that the heating chamber (4) comprises at least one radiant heater (11) in the form of a heating coil embedded in a ceramic layer, the ceramic layer providing an emission in the range of 2 to 3, 5 m is set up.

10. Oven according to at least one of the preceding claims, characterized in that the heating chamber (4) comprises at least one radiant heater (11) in the form of a bright radiator with a radiation maximum at a wavelength of less than 2 μιτι, in particular a bright halogen radiator (11 a) , a bright light-emitting diode (11 b) and/or a bright laser.

11. Oven according to at least one of the preceding claims, characterized in that the heating modules (3) each further comprise a heating rod (13) for irradiating an inner wall region (5b) of the preform (5) with infrared radiation, and that the lifting device (9) is also set up to raise and lower the holding device (7) and/or the heating rod (13) in order to insert the heating rod into the preform (5) or to pull it back out of it.

12. Oven according to claim 11, characterized in that the heating modules (3) further comprise a thermally insulating housing (23) for the heating rod (13), into which the heating rod (13) can be pulled back, with the housing (23 ) In particular, a cover (25) is provided in order to close the housing (23) in a thermally insulating manner when the heating element (13) is retracted.

13. Oven according to claim 11 or 12, characterized in that a plurality of radiators (15) with different and/or separately adjustable heating power are provided on the heating rod (13) in the longitudinal direction.

1 . Oven according to at least one of claims 11 to 13, characterized in that at least one ceramic layer for emitting infrared light is provided on the heating rod (13), in particular by converting bright radiation with a radiation maximum at a wavelength of less than 2 μm into a longer wavelength Radiation with a wavelength in the range of 2 to 3.5 pm.

15. Oven according to at least one of claims 11 to 14, characterized in that a radiation protection shield (17) which can be cooled by a liquid and/or air flow (14, 34) is provided on the heating rod (13) and/or the holding device (7), in order to shield and/or cool the mouth area (5c) from the infrared radiation emitted by the heating rod (13).