DE102007022386A1 - Heating plastic preforms used in e.g. bottle manufacture, employs annular microwave resonator around region to be heated - Google Patents

Abstract

The preform (1) has a region designated for heating and a further region which is not to be heated. The region to be heated is subjected to microwaves in a resonator. All of this region is heated simultaneously. It is alternatively heated progressively in steps or sections. The region is moved and/or heated continuously. The preform is moved longitudinally (A) or at right angles to this direction, into or through the disc- or plate-shaped resonator (11) which completely surrounds it. The path of preform movement, projected into the extended plane of the (TE wave) resonator during heating, is essentially circular. Movement through the resonator takes place repeatedly, no less than twice. This movement is superimposed on the circular movement, which is followed by the resonator. Preform temperature is measured internally and/or externally, once or more times, during the operation. The value is sent to a controller for the following heating process, or to control heating of the present preform. In an adjustment method, by measuring the temperature profile of the preform and comparison with a desired profile, the field strength distribution in the resonator is adjusted accordingly. Variants of these procedures are described, in accordance with the foregoing principles. Salient features include an optionally-moving microwave reflector, delivery to an associated polyethylene terephthalate (PET) stretch-blowing process. Heating may be intentionally non-uniform over the length, thickness and/or circumference. Microwave heating is supplemented by infra red heating. A microwave generator feeds the ring resonator. The equipment is further detailed. An independent claim IS INCLUDED FOR corresponding equipment.

Description

The The invention relates to a method according to the preamble of the claim 1, a device according to the preamble of claim 29 and An arrangement according to the preamble of claim 59.

at The production of plastic hollow bodies often becomes a process used in which preforms are first heated, and then deformed. A particular application of this technique is z. B. the production of food containers, in particular plastic bottles made from preforms become. These preforms are heated to and then to containers formed. The heating process is usually done with infrared or near infrared radiation. A disadvantage of these heating devices with infrared is that of the efficiency of heating operations with about 20% is very low.

It is therefore an object of the invention, a method, a device or to create an arrangement with which it is energy-saving Way possible is to heat plastic preforms.

The Task regarding of the procedure is solved by the features of claim 1, the task with respect to Device by the features of claim 29 and the task in terms of the arrangement by the features of claim 59.

The Process is used for heating of preforms, among preforms mainly from Plastic existing body to be understood, which formed after heating, in particular blown or stretch blown. Preferably, these are Plastic preforms making up containers for the food industry, especially bottles for the beverage industry getting produced. Mostly the plastic is um a thermoplastic, preferably PET. usable but are also other materials, such. PET derivatives / copolyesters, others Polyesters, polyamides, polyacrylics, polycarbonates, polyvinyls (such as PVC; EVOH; PVA) or polyolefins. Main focus in the selection of plastics must be placed on a good excitability. A measure of such good excitability is a high dielectric loss factor. The is called, it is also possible to heat plastics which do not have a high dielectric loss factor themselves, but by adding additives or targeted changes obtained on the plastic such.

These Plastic preforms consist of a mouth as well as a hull Ground area, the mouth area preferably has a thread and one or more beads, wherein at least one bead is preferably formed as a support ring is. In most cases it is not desirable that the upper part of the preform, so the mouth area is heated with, since this area finally should not be reshaped. To be deformed preforms are therefore often divided into different areas, either not at all or only a little heated should be. A little or not to be heated area but can also to be one who is very thin is and therefore does not need much deformation.

It It goes without saying that the areas of the preforms to be heated with the new heating method as previously can be heated completely in one step, where a preferred embodiment of the invention is that the to be heated Areas of the preforms are heated gradually or in sections. gradually means that the to be heated Area of the preforms in chronological succession step by step heated becomes. The preform is in several sub-areas - preferably 3 to 9 - divided, which heats in succession become.

Under a sectionwise warming becomes understood that although the to be heated Heated area at the same time will, however, regarding a height or thickness profiles different. Moreover, with a sectionwise Warming too a respect understood the extent of the preforms different heating become. By a circumferential different warming is it is possible different forms of containers, like z. B. oval or other contour container easier to produce.

According to one preferred embodiment of the invention, the heating of the Preforms made in a resonator. Under a resonator is a component to understand in the electromagnetic radiation is initiated and in which this the radiation by constant reflection for one certain period of time is held. It is desirable in the resonator a suitable microwave field with suitable field strength distribution to create. The field strength distribution depends on it the resonator geometry and the other components (e.g., microwave compact head) from. Suitable means that they are as possible for an isotropic warm-up is the same while for one anisotropic warming a non-uniform Field intensity distribution is sought. To achieve an optimal field strength distribution it is also possible to superimpose several microwaves, where the microwaves are the same as well as different Frequencies may have.

The resonator is designed such that the resonator height and thus also the extent of the microwave field preferably only a part of the Height of the preforms to be heated corresponds. Preferably, the height is 0.01 cm to 20 cm, more preferably 0.5 cm to 1 cm. Furthermore, the resonator is an open, annular or disc-shaped system into which the preforms can be introduced. For this purpose, it has a preferably round opening, the diameter of which corresponds approximately to 1.1 to 2 times the diameter of the preform and thus surrounds the preform in sections, at least in its entirety, at least in terms of its height. In this way, the preform can be moved into and out of the resonator. The resonator width is between 1 cm and 15 cm, preferably about 4 cm.

The opening of the Resonator is chosen so that the diameter is smaller than the wavelength of the preform too heated Radiation to exit the radiation from the resonator avoid. By such a geometric configuration of the resonator Is it possible, a microwave-based heating device for preforms which does not have to meet very stringent screening requirements. Depending on the geometry of the resonator can above and / or below the same protection devices be attached, which prevent the leakage of leakage radiation. preferred Protective devices are hollow cylinders whose geometry corresponds to the resonator geometry, the wavelength etc. is adjusted.

The opening of the Resonator is preferably mounted so that the preform in the direction of its longitudinal axis is moved in or through the resonator. However, it is also possible that the resonator has an opening comprising moving the preform into the resonator transverse to its longitudinal axis allows.

According to one preferred embodiment of the invention is each preform in the heating device associated with a resonator. An embodiment of the invention is in that the preforms are transported along a path, such as It is also commonly found in the art today, namely along two straight lines, each at their ends by deflection connected to each other.

A However, a particularly preferred embodiment of the invention is in that the resonators are in a circle around a fixed machine axis circulate. The preforms thus describe vertically with respect to a plane to the machine axis a circular path. This variant has the advantage that very high machine speeds can be realized. Preferably has this heating device 10 to 80 resonators, particularly preferably 20 to 40 resonators.

The warming the to be heated Areas preferably take place such that the preform in a Direction of its longitudinal axis and excluding is moved in the opposite direction through the resonator. It But it is also conceivable that the preforms not only one or twice, but several times are moved through the resonator. It is an even movement, such. B. a double, quadruple or sixfold movement through the resonator especially meaningful.

to warming However, the preforms it is also possible to use a Resonatorkavität, in the one to be heated Area of preforms is completely introduced. That's the way the process works the warming without movement of the preforms with respect to their longitudinal axis to go by, namely the preforms e.g. be introduced radially into the cavity. A vertical one Import or export of the preforms in / out of the cavity, however also conceivable.

Instead of the use of a cavity, can also be used a resonator stack, in which a different number of resonators is stacked on top of each other, thus to create a "cavity", in which are a preform his length can be introduced almost or completely.

A A particularly preferred development of the method is that the temperature of the preform before and / or during and / or after heating is measured at least once. This gives the method the advantage that a particularly accurate temperature control or temperature profiling of the preform possible is, it does not matter if the temperature from the inside and / or from the outside is measured. The measurement is carried out by means of a suitable sensor, such as. a pyrometer or a fiber optic sensor, the latter having the advantage that it is not due to microwaves is affected and that the microwaves are not through the sensor to be influenced. The pyrometer, however, has the advantage that it is very fast and non-contact is working.

The measured temperature values are preferably forwarded to a control and regulating device so that the preforms can be conditioned as precisely as possible, with a particularly preferred development of the invention being that, when the preforms are passed through the resonator repeatedly, the temperature is measured after the first passage is, so that in a second pass through the preform already an adjustment of the heating process can be made. In this way, it is possible to produce a very accurate temperature profile, on the one hand, to the other can be based on external circumstances such. B. the moisture of the preforms are particularly well received.

When Controlled variable for the whole Process can not only the temperature of the preform, but Also, the reflected power of the microwave can be used.

A special embodiment of the heating process including the temperature measurement is that the preform in a first step in the direction of its longitudinal axis through the resonator is moved, that in a second step, the temperature of the preforms is still measured during they are in the sphere of influence of the microwave field that the actual temperature profile of the preforms with a desired temperature profile in a third step and that the microwave power / the Field intensity distribution is adjusted immediately in the resonator in a fourth step, so that the preforms during the further movement through the sphere of influence of the microwave field already be subjected to an adapted radiation power. The advantage of this process variant is that a very quick response to external circumstances, like z. As the moisture content of the preform is possible. This can be the minimum time for the warming be used and it must u.U. less entry or exit cycles are performed by the resonator.

A Another variant of the method for heating is that in a first step of the preform in the direction of its longitudinal axis moved through the resonator, that in a second step the Movement of the preform is stopped in the direction of its longitudinal axis, that in a third step, the determination of a temperature profile of the Preform by means of height-adjustable Temperature sensors takes place, that in a further step, the actual temperature profile of the preform with a desired temperature profile is compared that in a penultimate step, the resonator in terms of its radiation power / field strength distribution is adjusted and that in a final step the preform in opposite direction moves through the matched resonator becomes. This variant of the method has, inter alia, the advantage that the compensator remains in the preform before the temperature measurement, in which the introduced heat can distribute better. This gives more accurate values regarding the desired Temperature profile of the preform.

It is self-evident also possible, To heat preforms To determine the temperature profile achieved at the end of the heating process and from that the settings for the next heating operations of the To determine preforms. This variant has the advantage that no powerful or very fast control algorithms or control structures are needed.

A more possible warming is that the preforms with the microwave off retracted into the resonator and with the microwave switched on be moved out of the resonator. This can be simple (Not very strongly profiled heating processes) energy-saving and fast accomplish.

According to one Particularly preferred embodiment of the invention, the preforms during the warming turned around its own longitudinal axis. The rotation can be done evenly, which - with a uniform field strength distribution - to a uniform temperature profile in terms of of the circumference, On the other hand, it can also be uneven, which then becomes one Temperature profiling with respect to the scope of the preforms leads. The second variant of the method may, for. B. in the production of Molded containers, such as z. B. oval container, be used.

The Production of molded containers can be supported be that in the resonator or in the cavity an anisotropic field strength distribution is generated, whereby a differentiated heating takes place even if the preforms are not rotated or moved. Another Possibility of Generation of different temperature ranges in preforms is that of the different residence time in the microwave field.

According to the invention a microwave heating unit at least one microwave generator, a microwave conductor as well a resonator on. The microwave generator may e.g. a magnetron, be a klystron or a gyrotron, generating the waves can be done in any way. The microwave conductor are preferably waveguides, with round or rectangular cross-sections especially to be preferred. A use of coaxial conductors can not be ruled out.

According to a preferred embodiment of the invention, the microwave generator is located in a microwave compact head, which further comprises at least one water load, a circulator, a microwave conductor and a heating transformer and connecting lines for the microwave generator and the heating transformer. The water load in the microwave compact head is needed to absorb excess microwave energy and render it harmless. This water load is preferably a silicone or plastic tube filled with water, with the water circulating in a continuous manner to be able to absorb enough residual energy.

Of another is present in the circulator, which preferably consists of three crossed coaxial conductors, and whose job it is microwaves into the compact head in the right direction. Of the Circulator is necessary because microwaves, from the place of their generation to the resonator and back again will not be allowed to flow back into the magnetron, otherwise it will be destroyed threatening. In this case, a transfer to the water load must therefore be carried out. For this purpose, ferrites integrated in the circulator, which are the microwaves each forward to the correct output.

Preferably is still a microwave tuner available, the setting the power in the resonator allows. The use of a manual tuner is just as possible as an automatic.

According to one embodiment The invention has a heating oven for preforms a central microwave generator, which generates the generated microwaves to the respective resonators. This solution has the advantage that the available technique, e.g. the microwave generator, only once needed becomes.

A Another embodiment of the invention provides several microwave generators each serving some resonators with microwaves. So it is e.g. possible, that four microwave generators for the Resonators available stand. This solution has the advantage that in case of failure of a microwave generator nevertheless, at least three quarters of the heating section continues to operate can be. According to one Particularly preferred development of the invention, everyone Resonator its own microwave compact head with microwave generator on. By this expression manages to give each preform a treatment that is as individual as possible to send.

A further advantageous embodiment of the invention is that the resonators with their associated microwave generators on a carousel turning around a central axis. This carousel arrangement has the advantage that very high engine power and thereby preform discharge services can be realized.

It However, it is also conceivable that the resonators attached to straps are those that do not describe a circular path, but at least partially rectilinear Web, e.g. in linear ovens. For this purpose, it is conceivable to attach the resonators to carriers and these using a chain to move along a line.

The Power of the at least one microwave generator is preferably in the range between 1 kW and 10 kW, with particularly good results be achieved with a generator power of 2 kW to 3 kW.

Of the Frequency range of for the warming too used microwaves is between 300 MHz and 300 GHz, wherein particularly preferred frequency ranges at 915 MHz, 2.45 GHz and 5.8 GHz are.

According to one advantageous development of the invention, each resonator a recording unit for On preforms. This receiving unit can preferably be rotated so that the preform moves around its own axis. A movement along the longitudinal axis However, the preform is also necessary to him in or out of the Resonator to move. Preferably, a moving unit has one combined lifting / lowering / rotary drive on. The movements of the preforms Although to find or in the resonator preferably in the direction of or around the longitudinal axis The preforms take place, however, is a movement about other axes also possible. So it is e.g. conceivable that the preform is not around its longitudinal axis is rotated, but that the preform about an axis through the Resonator performs an oscillating motion. This embodiment has the advantage that a more arbitrary heat distribution in the preform through the microwaves.

alternative but also the resonator can be moved relative to the preform.

A particularly preferred embodiment is that each preform a microwave heating unit assigned. Other arrangements where less heating units are available as preforms to find space in the device are also possible.

Around the capacity such a heating device to increase, It is also conceivable that several heating levels above each other are located. These levels of warming can either independently be loaded from each other, but it is also a run conceivable in which the preforms are introduced into the device in one plane be while they are led out of the device in the other plane.

A further advantageous heating variant is that the preforms with respect to their longitudinal axis experience no movement, but that the resonators along the Preforms are moved.

The warming can be absolutely individual for individual or for different groups of preforms are set. Independent of each other parameters to be set are e.g. Stroke, lifting speed, rotational speed, Microwave power, microwave tuning settings, field strength distributions in the resonator or impedance matching as a function of a measured dielectric constant. Individual settings can because of different reasons be necessary, e.g. because of the different moisture content of the preforms.

at the device is preferably a heating device for preforms from which PET bottles are made. An arrangement of a such a heating device in a machine arrangement comprising e.g. a stretch blow molder, a filler, a capper, a labeling machine or the like. Therefore, makes sense.

A further advantageous embodiment in that the warming device a slip ring transmitter for high voltage so that the transmission of energy from stationary Parts can be made in the moving parts.

According to one preferred embodiment of the invention, it is advantageous if the preforms not only with microwaves, but also with infrared radiation be charged. It is thus e.g. conceivable that the preform a basic heat profile is impressed by the infrared radiation and the exact temperature profiling first through the microwave is made. But this process is also conceivable so that only with the help of microwaves a basic temperature profile imprinted becomes, so then with the help of infrared radiation a more accurate Temperature profiling can be generated in the preform. Here But it is also conceivable that in a microwave oven in addition infrared radiator are attached so that the two heating methods in any Order, in any zones and in any intensity combined can be.

A concrete embodiment The invention will be described in more detail with reference to the following drawings.

there demonstrate:

1 an isometric view of a heating device,

2 a section of the heating device according to 1 .

3 A detailed view of a heating device,

4 a microwave compact head,

5a to 5e a schematic process sequence for heating preforms,

6 a plan view of a plant for producing containers,

7 a side view of a resonator,

8th a side view of a transfer situation of a resonator and a resonator,

9 an isometric view of an embodiment of a heating device,

10 a section of the illustration according to 9 and

11 a further embodiment of a microwave waveguide with resonator

1 shows a circular heater for preforms 1 in which they are moved in the course of heating in accordance with the circumference of the heating device in a circular path. The heating device has a carrier 4 on, which simultaneously represents a rectangular waveguide. At this carrier 4 Various units are attached, such as eight microwave compact heads 20 and forty microwave heating units 3 , These on the carrier 4 attached units run together around the machine axis 5 around. The transfer from an upstream unit to the oven 40 takes place by means of a star, such as. B. a sawtooth or a staple star.

2 shows a section of the oven 40 according to 1 , here the microwave heating unit 3 can be explained better. Again, the microwaves compact microwaves generating the microwaves 20 to see that directly with the carrier 4 who is here a waveguide 22 represents, are connected. From the carrier 4 towards the microwave heating unit 3 is a coupling element 8th attached, that of microwave compact head 20 generated microwaves from the carrier 4 into the microwave heating unit 3 couples.

The microwave heating unit 3 consists of an S-shaped bent rectangular microwave waveguide, the first end of the carrier 4 is attached and at its second end a resonator 11 is attached. The resonator 11 is a disc / plate-shaped, inside hollow element, in the middle of a circular hole is present. The dimensions of the hole are chosen so that the ever because preforms to be heated 1 can be easily passed through, wherein the resonator 11 has a height that corresponds to only a portion of the height of the preforms. The hollow resonator 11 represents an extension of the microwave heating unit 3 and is - like the Holleiter - flows through microwaves. In the area of the resonator 11 is at the microwave heating unit 3 a temperature sensor 24 fixed the temperature of the resonator 11 immersing or dipping or led out of him preforms 1 measures.

Furthermore, on the microwave heating unit 3 a microwave tuner 23 fixed by means of which it by changing the conductor space of the microwave heating unit 3 it is possible to influence the microwaves - ie to optimize the field strength distribution with imported preform so that the reflected and not from the preform 1 absorbed amount of energy is minimized - and thus also the heating process of the preforms 1 to control or regulate.

Radially outward in front of the microwave heating unit 3 upstream there is a receiving unit 25 whose fundamental task is the preform 1 and to apply a movement that allows effective heating. The pickup unit 25 consists of a preform holding unit 26 and a movement unit 27 , The preform holding unit 26 Here is a thorn that is in the mouth of the preform 1 penetrates and thus holds this. Preferably, at least a part of the preform holding unit is to be manufactured from a suitable non-metallic material, since otherwise leakage radiation may escape from the cavity. Preferred materials are plastics with low dielectric loss factor, such as Teflon.

It But here is not just a holding by an internal gripper but also by an external gripper conceivable.

The movement unit 27 is preferably a multifunctional drive, with either different drives to the moving unit 27 be merged, or where the motion unit 27 is formed by a drive that meets all the motion requirements. On the one hand, a lowering movement is required, which is the preform 1 along its longitudinal axis A from above into the resonator 11 introduces. On the other hand, a lifting movement is required, which is the preform 1 along its longitudinal axis back out of the resonator 11 out leads. Another movement that makes the heating process enormously more flexible is a rotary motion that moves the preform 1 to turn about its longitudinal axis A.

3 shows another embodiment of the preform heating unit 1 on. The main differences are that each microwave heating unit 3 its own microwave compact head 20 assigned. This is the microwave heating unit 3 , which is again formed here as Rechteckmikrowellenhohlleiter is bent radially outwardly c-shaped. The one end opens in the microwave compact head 20 while at the other end again a resonator 11 is attached. Furthermore, the microwave heating unit 3 again a microwave tuner 23 which performs the same task as the one according to 2 , Again, the Vorfromling 1 through a receiving unit 25 held a preform holding unit 26 and a movement unit 27 includes.

4 shows a section through the microwave compact head 20 , In it is a microwave generator 21 such as As a magnetron or a klystron, generated by the microwaves and by means of a microwave conductor 22 to the circulator 29 and to its applicator output 30 be directed. The microwave compact head 20 has two connections 32 on, with one connection being the plug connection for the heating voltage and the other connection being the connection for the high voltage for the microwave generator 21 is.

Microwaves coming from the applicator output 30 in the in 4 not shown microwave heating unit 3 are constantly reflected and come back to the circulator 29 of the microwave compact head 20 back. To prevent penetration of the microwaves into the microwave generator 21 to prevent is the circulator 29 able to selectively reflect reflected radiation towards the water load 28 forward. The water load 28 is formed here by a U-shaped silicone tube, which is traversed by the cooling water. Through this microwave compact head 20 is the generation of microwaves for the heating of the preforms in a very compact and compact space 1 feasible.

5 shows in five steps different positions of the preform 1 during its heating in the heating unit. The preform 1 has an area to be heated 2 , a non-heating area 10 as well as one in the area 10 located support ring 9 on. The preform 1 is concentric on a preform holding unit 26 attached. By in the 2 and 3 described movement unit 27 it is now possible the preform 1 in the direction of the arrow 17 and 18 through the resonator 11 to move. The black bar 33 sets the microwave influence range 23 of the resonator, not shown here 11 In a first step is according to 5a started, the preform 1 along its longitudinal axis A in the direction of the arrow 17 in the microwaves sphere of influence 23 inside move.

5B already shows a position in which the preform 1 a little way through the microwave influence area 33 was moved.

The temperature sensor 24 , which is mounted just below the resonator level TE, thereby has the already changed by the microwaves temperature of the preform 1 taken from the outside.

In principle, a temperature measurement is also within the preform 1 conceivable.

5C shows a position in which already the entire area of the preform to be heated 1 in the microwave influence area 33 was or is. This is also the turning point, after which it reaches the parison 1 from the microwave influence area 33 along the longitudinal axis A in the direction of the arrow 18 takes place.

5D shows a position that of 5B corresponds, where here the preform 1 along its longitudinal axis A in the direction of the arrow 18 is moved. With the beginning of moving out of the preform 1 from the microwave influence area 33 is also made an adjustment of the heating by means of microwaves, so that the target temperature of the preform 1 can be reached exactly. Through this combination of temperature sensor 24 and adaptation of the microwaves is as accurate as possible a temperature profile in the preform 1 contribute. The preform holding unit 26 can be equipped with a hole, not shown here, through which, for example, a temperature sensor in the interior of the preform to be heated 1 penetrates, or through the specific media, for example, a cooling medium for temperature compensation can penetrate.

5E shows a position that the 5A corresponds, in which case the heating process is already completed.

Now, for example, a rest phase can follow, but it can also be a second or third heating process by passing through the microwave influence area 33 be performed.

6 shows an apparatus for producing containers. This device has a preform memory 34 on, in which the preforms 1 be sorted in unsorted.

A roll sorter 35 takes over the singling and sorting of the preforms 1 which then turns into a feed chute 36 which are the feed to the oven 40 performs.

In the oven 40 become the preforms 1 heated as described. After heating, a transfer takes place in the stretch blow molding machine 14 making finished containers. After the container is made a transfer to the filling machine 15 and in a capper and / or a labeling machine not shown here. This creates a completely filled and sealed container, such as a beverage bottle. Between the oven 40 and the stretch blow molder 14 Preferably at least two transport stars are mounted, which is an active and / or passive cooling of the heated preforms 1 cause. At this point in the manufacturing process, it may be necessary for the heated preforms to be provided with a compensation time so that the energy introduced can be distributed evenly. This compensation time can be made available eg via built-in transport stars. A compensation or cooling time may also be necessary again after the stretch blow molding process. Here again it is possible to provide an active and / or passive cooling of the container. An active cooling can be done eg with water, air, nitrogen or other media from inside or outside. Passive cooling can be achieved by providing a transport path between the stretch blow molder 14 and the downstream machine.

7 shows a resonator 11 , which at its top and bottom each have a hollow cylinder 11a having. This hollow cylinder has mainly the effect of shielding microwaves. This protective device is cylindrical here, but it is within the scope of expert action to design this protective device also differently, eg with an angular cross-section. In the effective range of the microwave is located in the resonator 11 a reflector element 19 , Task of this reflector element 19 is it, the dome of the preform 1 in addition to warm. The reflector element 19 is designed so that the microwave radiation in the direction of the dome of the preform 1 is focused.

Advantageously, the reflector element 19 designed so that it moves during the movement of the preform 1 through the resonator 11 at least in the range of effect of the microwave always the same distance to the dome of the preform 1 Has. This can for example be accomplished by the reflector element 19 in the direction of the longitudinal axis A of the preform 1 with through the resonator 11 is moved. But it is also conceivable that a plurality of reflector elements 19 are mounted in the field of action of the microwave, and these are conceivable in different heights. It is then possible, respectively, the reflector elements 19 laterally in the path of movement of the preforms 1 to pan. The reflector element 19 is designed to be easily replaceable. This has the advantage that different preform geometries in the resonator 11 can be processed optimally.

8th shows a preferred transfer situation of preforms 1 to the device and at the same time a takeover situation of preforms 1 from the resonator 11 before they are transported on to the next machine. The transport of the preforms 1 to the resonator 11 to and from the resonator 11 away, is here by grapple 50a . 50b performed. The grippers are preferably part of a transfer or acceptance starter, here by the gripper 50a and 50b as well as the center column 37 are indicated only schematically. The gripper 50a takes over a preform 1 from an upstream machine, such as a preform singulator, and then transfers it to a preform holder unit 26 , which then performs the above-described treatment process by the preform 1 at least once along its longitudinal axis A through the resonator 11 to be led. If the preform occurs after its treatment at the lower side of the resonator 11 out, he can from a gripper 50b that with the same center column 37 Actively connected is like the gripper 50a , gripped and transferred to a downstream positioned machine, such as a labeller or a filling machine. In rotary machines, this arrangement has the advantage that a very large rotation angle can be used as a process time. With such an arrangement process angles between 300 ° and 355 ° can be achieved. In addition, this solution is very space-saving, since only one star transport is used as inlet and outlet star, while in conventional solutions two transport stars are installed.

9 shows an isometric view of another embodiment of a microwave heating device, which is formed in Rundläuferbauweise. The device has a plurality of receiving units 25 on, each with several (at least two) recording units 25 on a recording medium 38 are attached. The recording media each have a movement unit 27 on that for the lifting movement of the preforms 1 in the direction of the resonators 11 responsible is. In addition, the preform holding units 26 a drive for inducing a rotational movement in the preforms 1 on. The microwave heating device comprises a plurality of microwave compact heads 20 each made up of a microwave tuner 23 , a water load 28 and a microwave generator 21 consist. For space reasons, each is a microwave compact head 20 a recording unit 25 at the top of a disk-shaped microwave conductor 22 and a microwave compact head 20 on the bottom. The microwave conductor 22 is as a carrier 4 formed and has a flat disc shape, which is hollow inside, to the microwaves from the microwave generator 21 in the direction of the resonator 11 to be able to lead. The microwave conductor 22 can be designed so that two discs are mounted on each other, which then form an inner cavity and thereby become a waveguide, but the conductor can also be constructed so that only segments are mounted on each other, so that no continuous circular disc pile is created, but that every resonator 11 his demarcated waveguide 22 forms.

10 shows a section through the microwave conductor 22 according to 9 , It can be seen that two waveguide segments 39 are mounted in the resonator TE on each other and thus a microwave conductor 22 form. The two Holleiter segments 39 are each ring-shaped. In the circumferential direction on the outside of the waveguide segments 39 are the resonators 11 with the respective above and below arranged hollow cylinders 11a , In section through the microwave heater 22 the individual components are easy to recognize. At the bottom of the waveguide segments 39 is the microwave generator 21 as well as the circulator 29 and the water load 28 , Through the circulator, the microwaves from the producer 21 in the microwave conductor 22 and there at the tuner 23 over in the direction of the resonator 11 directed. The tuner is designed so that three tuning pins 23a . 23b and 23c in the microwave conductor 22 immerse, thereby affecting the cross-section of the pipe. In this way, an adaptation of the heating of the preforms 1 in the resonator 11 be made. In this presentation is currently a preform 1 in the resonator 11 ,

11 shows a further embodiment of a microwave conductor 22 , Contrary to the embodiment according to 10 is the microwave conductor 22 not here from two ring or disc-shaped waveguide segments 39 built, but as a waveguide profile, of which a plurality of longitudinal pieces are joined together to form an entire waveguide. Again, the microwave tuner 23 with his three pins 23a . 23b and 23c to see. Towards the microwave generator, which is not visible here 21 to the resonator 11 is in addition to setting an optimal microwave distribution in the resonator 11 a panel 41 provided that a diameter jump of the microwave conductor 22 caused. For Montagetechnischnen reasons is a fastener 42 provided on which the aperture 41 is attached. The fastener 42 has similar passage sizes as the aperture 41 on.

Claims (62)

Process for heating preforms ( 1 ) of a thermoplastic material, with a region to be heated ( 2 ) and one not to he warming area ( 6 ), the preforms ( 1 ) undergo a forming process after being heated, characterized in that the area to be heated ( 2 ) of the preforms ( 1 ) at least during part of the time duration of the heating in a resonator ( 11 ) is applied with microwaves. Method according to claim 1, characterized in that the entire area to be heated ( 2 ) of the preforms ( 1 ) is heated simultaneously. Method according to claim 1, characterized in that the area to be heated ( 2 ) of the preforms ( 1 ) is heated gradually and / or in sections successively. Method according to claim 1, characterized in that the area to be heated ( 2 ) of the preforms ( 1 ) is continuously moved and / or heated. Method according to one of claims 1 to 4, characterized in that the preforms in the direction of its longitudinal axis (A) in / through the substantially disc or plate-shaped resonator ( 11 ) moving the preforms ( 1 ) completely surrounds. Method according to one of claims 1 to 5, characterized in that the preforms ( 1 ) in a direction perpendicular to its longitudinal axis (A) into / through the resonator ( 11 ) are moved. Method according to at least one of the preceding claims, characterized in that the path of movement of the preforms projected into a resonator plane (TE) ( 1 ) is substantially a circular path during heating. Method according to at least one of claims 3 to 7, characterized in that each section to be heated ( 7 ) of the preforms ( 1 ) several times, but at least twice through the resonator ( 11 ) is moved. Method according to at least one of claims 3 to 8, characterized in that the preforms ( 1 during movement along a substantially circular path in the direction of its longitudinal axis (A) into the resonator ( 11 ) are guided in order then to exit the resonator in the opposite direction (FIG. 11 ) to be led out. Method according to at least one of the preceding claims, characterized in that each preform ( 1 ) in a heating area ( 2 ) is heated completely surrounding cavity. Method according to claim 10, characterized in that that is the cavity on a substantially circular Train moves. Method according to at least one of the preceding claims, characterized in that the temperature of the preforms ( 1 ) is measured at least once before and / or during and / or after heating. Method according to at least one of the preceding claims, characterized in that the temperature of the preforms ( 1 ) is measured outside and / or inside. Method according to at least one of claims 12 and 13, characterized in that the measured temperature values are sent to a control and regulation device ( 13 ). Method according to claim 14, characterized in that that with the measured temperature values, the subsequent heating processes regulated become. A method according to claim 14, characterized in that with the at least one measured temperature value of a preform ( 1 ) the heating process of the same is regulated. Method according to at least one of claims 8 to 16, characterized by the steps: a. Moving the preforms ( 1 ) in the direction of its longitudinal axis (A) through the microwave acted upon resonator ( 11 b. Measuring the temperature of the preforms ( 1 ) after the first passage through the resonator ( 11 c. Comparison of the actual temperature profile of the preforms ( 1 ) with a desired temperature profile, d. Adjusting the field strength distribution in the resonator ( 11 ), e. Moving the preforms ( 1 ) counter to the direction of the longitudinal axis (A) by the adapted, with microwaves resonator ( 11 ). Method according to at least one of claims 8 to 16, characterized by the steps: a. Moving the preforms ( 1 ) in the direction of its longitudinal axis (A) through the microwave acted upon resonator ( 11 b. Measuring the temperature of the preforms ( 1 ) during this heating phase, c. Comparison of the actual temperature profile of the preforms ( 1 ) with a desired temperature profile, d. Adjusting the field strength distribution in the resonator ( 11 ) before the preforms reach the resonator ( 11 ) leave again. Method according to at least one of claims 8 to 16, characterized by the steps: a. Moving the preforms ( 1 ) in the direction of its longitudinal axis (A) through the microwave acted upon resonator ( 11 b. Stopping the movement of the preforms ( 1 c. Determination of the temperature profile of the preforms ( 1 ) by means of movable temperature sensors from inside and / or outside, d. Comparison of the actual temperature profile of the preforms ( 1 ) with a desired temperature profile, e. Moving the preforms ( 1 ) in the opposite direction through the matched and microwaves resonator ( 11 ). Method according to at least one of claims 8 to 16, characterized by the steps: a. Moving the preforms ( 1 ) in the direction of its longitudinal axis (A) through the resonator ( 11 b. Applying the resonator ( 11 ) with microwaves, c. Moving the preforms ( 1 ) by the microwave loaded resonator ( 11 ). Method according to at least one of the preceding claims, characterized in that in the resonator ( 11 ) a reflector element ( 19 ), which deflects the radiation so that the closed side of the preform ( 1 ) is additionally heated. A method according to claim 21, characterized in that the distance between the reflector element ( 19 ) and the preform ( 1 ) is the same at least in the effective range of microwaves. Method according to at least one of claims 1 to 20, characterized in that the preforms ( 1 ) at least partially about its longitudinal axis (A) rotate. Method according to at least one of claims 1 to 23, characterized in that the preforms ( 1 ) are rotated unevenly around their longitudinal axis (A) during heating. Method according to at least one of the preceding claims, characterized in that the plastic, in particular PET preforms ( 1 ), by a blowing process, in particular a stretch blow molding. Method according to at least one of the preceding claims, characterized in that the preforms ( 1 ) are heated unevenly with respect to their length and / or their thickness. Method according to at least one of the preceding claims, characterized in that the preforms ( 1 ) are heated unevenly with respect to their circumference. Method according to at least one of the preceding Claims, characterized in that the preforms are filled with both infrared, as well as being exposed to microwave radiation. Apparatus for heating preforms ( 1 ) with microwaves comprising at least one microwave generator ( 21 ), a microwave conductor ( 22 ) and a resonator ( 11 ). Device according to claim 29, characterized in that the resonator ( 11 ) is substantially annular, wherein an opening is provided through which a preform ( 1 ) can be passed. Device according to claim 29, characterized in that the opening of the resonator ( 11 ) is surrounded by a hollow cylinder. Device according to one of claims 29 to 31, characterized in that in the resonator ( 11 ) a reflector element ( 19 ) is located. Apparatus according to claim 32, characterized in that the reflector element ( 19 ) is designed movable. Apparatus according to claim 32, characterized in that the reflector element ( 19 ) in the longitudinal direction of the preform ( 1 ) and / or substantially perpendicular thereto. Device according to claim 29, characterized in that the microwave generator ( 21 ) Part of a microwave compact head ( 20 ) which still has at least one water load ( 28 ), at least one circulator ( 29 ), at least one microwave conductor ( 22 ), at least one heating transformer ( 31 ) and connecting cables ( 32 ) for the microwave generator ( 21 ) and the heating transformer ( 31 ). Device according to at least one of claims 29 to 35, characterized in that it further comprises at least one microwave tuner ( 23 ) and / or at least one temperature sensor ( 24 ) having. Device according to at least one of claims 29 to 36, characterized by at least one receiving unit ( 25 ) for preforms ( 1 ). Apparatus according to claim 37, characterized in that the receiving unit ( 25 ) a preform holding unit ( 26 ) and at least one movement unit ( 27 ) for preforms ( 1 ) contains. Apparatus according to claim 38, characterized in that it is in the movement unit ( 27 ) for preforms ( 1 ) is a combined lifting / lowering / rotary drive. Apparatus according to claim 38, characterized in that it is in the movement unit ( 27 ) for preforms ( 1 ) is at least one lifting / lowering and at least one rotary drive. Device according to at least one of claims 29 to 40, characterized in that the preform holding unit ( 26 ) an outer and / or an inner gripper for preforms ( 1 ). Device according to at least one of claims 29 to 41, characterized in that it comprises at least one microwave heating unit ( 3 ), at least consisting of a resonator ( 11 ), a microwave conductor ( 22 ), a tuner ( 23 ) and a recording unit ( 25 ), having. Device according to claim 42, characterized in that each preform ( 1 ) a microwave heating unit ( 3 ) assigned. Apparatus according to claim 43, characterized in that the microwave heating unit ( 3 ) at one end with the microwave compact head ( 20 ) and at the other end with the resonator ( 11 ) is in operative connection. Device according to claim 42, characterized in that each preform ( 1 ) a microwave heating unit ( 3 ) and a microwave compact head ( 20 ) assigned. Device according to one of claims 42 to 44, characterized in that a central microwave generator ( 21 ), which is accessible via microwave conductor ( 22 ) with the at least one microwave heating unit ( 3 ) connected is. Device according to claims 42 to 44, characterized in that it comprises n microwave generators ( 21 ) and m microwave heating units ( 3 ), where: m> n. Device according to at least one of claims 29 to 47, characterized in that they are designed as a rotating machine type is trained. Device according to claim 48, characterized in that it comprises at least two parallel planes in which preforms ( 1 ) are heated. Device according to at least one of claims 42 to 48, characterized in that the microwave heating units ( 3 ) on a support ( 4 ) and the carrier ( 4 ) with a machine axis ( 5 ) is operatively connected. Device according to claim 50, characterized in that the carrier ( 4 ) a microwave conductor ( 22 ). Device according to at least one of claims 42 to 51, characterized in that it comprises m microwave heating units ( 3 ) and o recording units ( 25 ), where o> = m. Apparatus according to claim 52, wherein: o = 2 · m. Device according to claim 29 to 51, characterized in that it is used for heating preforms ( 1 ) is made of plastic, in particular for preforms ( 1 ) made of PET. Device according to at least one of claims 29 to 54, characterized in that it is integrated in a machine arrangement, which further comprises at least one stretch blow molding machine ( 14 ) contains. Apparatus according to claim 55, characterized in that the stretch blow molding machine ( 14 ) is a Rotationsstreckblasmaschine. Device according to at least one of claims 29 to 56, characterized in that before and / or after the furnace ( 40 ) an infrared heating device is present. Device according to at least one of claims 29 to 56, characterized in that at the periphery of the furnace ( 40 ) Infrared heating devices are available. Arrangement for producing containers, at least consisting of a device for heating preforms ( 1 ) according to at least one of claims 42 to 58, and a stretch blow molding machine ( 14 ). Arrangement for producing containers according to claim 59, characterized in that between the device for heating preforms ( 1 ) and the stretch blow molder ( 14 ) Devices are mounted for active and / or passive cooling. Arrangement according to claim 60, characterized that for passive cooling at least two transport stars are present. Arrangement for producing containers according to one of claims 59 to 61, further characterized by at least one filling machine ( 15 ) and a closing machine ( 16 ).