Patent Application
20180369770
The invention relates to a device for processing thermoplastic material, which comprises a storage container for receiving plastic particles or a conveying line for the transport of plastic particles, a conveying screw connected to the storage container/to the conveying line at a transfer opening, and an extruder which connects to the conveying screw. In addition, the invention relates to a method for operating the above device.
A device and a method of the above-mentioned type are basically known from the prior art. For example, EP 0 934 144 B1 discloses for this a device for processing thermoplastic material. The device comprises a machine housing with a feed hopper and a driven pusher, which presses the plastic material, which is situated on a base plate and is to be processed, into a processing drum or respectively into a conveying tube. Blades are mounted in a helical manner on the processing drum. The blades and the conveying screw which connects thereto convey the broken up plastic material to a screw of an extruder, into which the plastic material is delivered.
A disadvantage in the known solutions in particular is the temperature at the inlet to the extruder, said temperature being difficult to predict and to regulate. This depends inter alia on the processed material (in particular on its thermal capacity), the throughput and also the shape and size of the plastic particles. By friction, shearing work and compression, a distinct heating can already occur in the conveying screw, so that the plastic particles stick together or become stuck to the extruder inlet and can clog the latter. Basically, however, it is also conceivable that the plastic particles are comparatively cold at the inlet of the extruder, for example if plastic with a very low temperature is delivered for further processing. As the extruder has only limited means for influencing the temperature, the reaching of a set-point temperature at the nozzle of the extruder according to the prior art can under some circumstances not be guaranteed in every case.
It is therefore an object of the invention to indicate an improved device and an improved method for processing thermoplastic material. In particular a set-point temperature is to be able to be reached with greater reliability in the extruder and/or at the inlet of the extruder and at its nozzle.
The problem of the invention is solved by a device of the type named in the introduction, which has a tempering device arranged in the course of the conveying screw and
a) at least one temperature sensor, which is arranged in the course of the conveying screw and/or in the course of the extruder, means for influencing the tempering device and an open loop control/closed loop control connected to the at least one temperature sensor and to the means for influencing the tempering device and/or
b) means for detecting a load of a drive of the extruder, means for influencing the tempering device and a closed loop control connected to the detection means and the influencing means.
The problem of the invention is solved furthermore by a method for operating the above device, in which the plastic particles are temperature-controlled in the course of the conveying screw by a tempering device.
Through the proposed provisions, a set-point temperature can be reached with greater reliability in the extruder and/or at the inlet of the extruder and at its nozzle. The tempering device can be formed for example by a heating device, a cooling device or a combined heating and cooling device.
The means for influencing the tempering device can be formed by an adjuster for the heating/cooling power, for example by a transistor or thyristor for adjusting a current through a heating coil of the tempering device. The influencing means could, however, for example also be formed by an electrical energy source which is adjustable with regard to voltage and/or current, to which energy source the heating coil is connected. If operation with a liquid or gaseous heat carrier is provided, the inflow to the tempering device can be adjustable by means of a valve which is connected into the flow or return, or else via the adjusting of an output of a pump or of a compressor, which is connected into the circuit of a heat carrier. It is also conceivable that the heat carrier can be directed in an adjustable manner via a bypass. Additionally or alternatively, provision can also be made that the temperature of the heat carrier is adjusted via the output of a heat exchanger, which is connected to the tempering device.
It is conceivable that the plastic particles which are fed to the extruder are cooled by means of the tempering device, for example if material with a very high temperature has been delivered and/or has low thermal capacity and/or has a lower melting temperature and/or has been heated excessively by friction, shearing work and compression in the conveying tube. Thereby, a clogging or sticking of the extruder inlet or respectively a sticking of the plastic particles on the latter is prevented or at least reduced.
Material which is fed to the extruder can, however, also be heated by means of the tempering device, for example if it has been delivered with a very low temperature and/or has high thermal capacity and/or has a high melting temperature and/or has not been heated in the conveying tube in the expected manner by friction, shearing work and compression.
Generally, the heating of the plastic particles takes place in the interior of the extruder by internal friction, wherein the drive power of the extruder is converted almost entirely into heat. In other words, the mechanically emitted motor output is converted almost entirely into thermal output, and the drive motor of the extruder acts de facto as heating. The longer the extruder is, all the more heat can be introduced into the plastic. Through the enormous shearing forces, in extreme cases also a negative impairment of the material quality can occur.
A comparatively high charging temperature of the extruder is now advantageous in so far as the material in the extruder is melted gently, because it arrives, already pre-warmed, into the extruder. Thereby, the drive power for the extruder can be reduced and also its overall length can be reduced. The energy consumption of the extruder per unit of weight of the extruded material is therefore likewise reduced and/or the material throughput is increased. In addition, the material wear in the extruder can also be reduced.
Ultimately, it is therefore also not always expedient to cool the plastic particles excessively in the conveying screw, in order to indeed prevent a sticking of the extruder inlet or respectively a sticking of the plastic particles to the latter. Rather, provision can be made that the temperature of the plastic particles at the extruder inlet is in fact so high that none of the mentioned negative phenomena occurs (excessively). Thereby, maintenance to the disclosed devices can be largely avoided, or respectively maintenance intervals can be extended, on the one hand owing to the extruder inlet remaining free, on the other hand also owing to the gentle mode of operation of the extruder.
In case a), the supply and/or removal of heat is adjusted or regulated directly as a function of a temperature of the plastic particles. In case b), in contrast, the supply and/or removal of heat is adjusted or regulated as a function of a load of the extruder and therefore indirectly via the temperature of the plastic particles. Here, the circumstance is utilized that the drive of the extruder, when the set-point temperature is reached in the extruder, is loaded in a characteristic manner. When the load lies above this characteristic value, this is an indication that the plastic particles are too cold and are not melted properly. When the load lies below this characteristic value, this is an indication that the plastic particles are too hot and are excessively fluid. Accordingly, in an advantageous method in case a) the removal of heat is intensified, when the temperature in the extruder and/or at the inlet of the extruder increases and vice versa. In an analogous manner, advantageously the removal of heat is intensified when the load in the extruder and/or at the inlet of the extruder reduces and vice versa.
Advantageous embodiments and further developments will now emerge from the subclaims and from the description, viewed together with the figures.
It is advantageous if the cooling power of the cooling device or of the combined heating and cooling device is greater than an power supplied to the plastic particles in the conveying screw by friction. Thereby, it is possible to cool the plastic particles before they enter into the extruder and to prevent or at least reduce a clogging or sticking of the extruder opening or respectively a sticking of the plastic particles on the latter. In a further preferred variant, the cooling power of the cooling device or of the combined heating and cooling device is greater than a drive power of the conveying screw. The latter is generally easier to determine than an power supplied to the plastic particles in the conveying screw by friction, whereby also the dimensioning of the cooling device or of the combined heating and cooling device is simplified. A slight oversizing which has possibly taken place thereby, can serve as security.
It is favourable if the at least one temperature sensor in case a) is arranged, in transport direction of the conveyed plastic particles, after the tempering device. In this way, the tempering device can be controlled. Basically, however, it is also possible that the at least one temperature sensor is arranged, in transport direction, before the tempering device. Such temperature sensors can likewise be included into the control of the tempering device. Of course, it is also possible merely to control the tempering device. In particular, the case is possible here that all temperature sensors are arranged, in transport direction, before the tempering device.
It is particularly advantageous if the at least one temperature sensor in case a) is arranged in the region of the transition between the conveying screw and the extruder. In this way, a predeterminable (set-point) temperature of the plastic particles which are fed to the extruder, can be maintained particularly well. Preferably, this type of control or respectively this control loop is combined with a further control loop which controls the heating in the extruder. The control loop of the conveying screw and the control loop of the extruder can operate independently of one another, or a further control loop can also be superordinate to the two control loops.
It is also conceivable that the temperature sensor in case a) is arranged in the course of the extruder, in particular in the region of the outlet or respectively of the nozzle. Thereby, the proper melting of the plastic particles can be regulated well. For example, the tempering device and a heating are provided in the extruder as actuating elements. In particular, the tempering device can be prioritized here, which means a heater of the extruder is only switched on when a heating through the tempering device is not sufficient.
In a particularly advantageous variant embodiment, the heat supply in case b) is increased when the load of the extruder increases, and vice versa. Accordingly, it is advantageous if the control is arranged to increase the heat supply through the tempering device when a load of the extruder increases and vice versa. Thereby, warmer material is, in turn, supplied to the extruder when its heating power is not sufficient for the proper melting of the plastic particles, and cooler material when the plastic particles are melted in the extruder excessively.
Generally, the open loop control/closed loop control of the tempering device can be based solely on a temperature measurement in or on the extruder, solely on a measurement of the load of the drive of the extruder or on a temperature measurement and a measurement of the load of the extruder drive.
It is favourable if for the determining of the load of the extruder a rotation speed of a drive of the extruder, a current received by this drive, or the torsion of a shaft in the drive is measured. For this purpose, a sensor for measuring a rotation speed of the drive of the extruder (e.g. a digital incremental encoder) can be provided, a sensor for measuring a current received by the drive (e.g. a voltage meter on a current-sensing resistor) or, for example, also a sensor for measuring the torsion of a shaft in the drive (e.g. a measuring bridge with strain gauge). Generally, the drive can also have a gear unit. The above-mentioned rotation speed and the above-mentioned torsion can therefore also be taken at a component in the gear unit. Generally, the extruder is then loaded more intensively if the rotation speed of the drive reduces, the current received by the drive increases or the torsion of a shaft in the drive increases.
Furthermore, it is particularly advantageous if
Accordingly, it is also advantageous if the presented device has a sensor for identifying the type/sort of the processed plastic and/or an input means for inputting the type/sort of the processed plastic,
In the presented variant, control can generally take place by means of a set-point temperature in the extruder and/or at the inlet of the extruder, when in the course of the conveying screw and/or in the course of the extruder at least one temperature sensor is arranged (case a) or by means of a set-point load of the drive of the extruder, when means are provided for detecting a load of a drive of the extruder (case b).
The input means can be formed for example by a keyboard, a touchscreen or, for example, also by a reading device for a storage medium, on which the type/sort of the processed plastic and, if applicable, also the allocation to a set-point temperature/set-point load is stored.
In a further particularly advantageous variant of the presented method,
In particular in this context, it is also advantageous if the device has a plurality of temperature sensors arranged in the transport course of the plastic particles. In this variant, not only is a single set-point temperature prescribed selectively, but a set-point temperature profile along at least a portion of the transport course of the plastic particles, which leads through the conveying screw and the extruder. Thereby, the device can be adjusted even better to the type/sort of the processed plastic.
Generally, it is also conceivable that the method mentioned above for a set-point temperature profile (case a) is carried out in an analogous manner alternatively or additionally by means of a set-point load profile (case b). This is possible in particular when several drive motors are integrated into the transport course of the plastic particles. For example, the melting of the plastic particles can take place in several extruder stages which are driven independently of one another, or also several conveying screws which are driven independently of one another can be provided.
In particular, the temperature of the plastic particles, depending on type/sort in their entire transport course or up to a position in the extruder can be
The first case is suitable in particular for plastics to which relatively little energy is supplied by friction in the conveying screw, or respectively plastics which have a comparatively high melting point. Examples of these are polyamide (PA) and polyethylene terephthalate (PET). The other two cases concern plastics to which a relatively large amount of energy is supplied through friction in the conveying screw, or respectively plastics which have a comparatively low melting point. Examples of these are polyolefins and ethylene vinyl acetate (EVA).
In a further advantageous variant embodiment, the conveying screw has comminution means arranged thereon, which are formed in particular by teeth and/or by continuous cutters and/or by blades. In this way, the material conveyed into the conveying screw can be further communited, before it reaches the extruder. Therefore, material of optimum size can be fed to the extruder, whereby a proper intermixing and a proper melting of the material can be guaranteed, and a clogging of the extruder can be prevented. The conveying screw can therefore also be (partly) regarded as a processing drum/comminution screw, or respectively can include this function.
The conveying screw can be occupied continuously by cutters and/or teeth and/or blades, or can have these only in a (continuous) partial region (i.e. in a comminution region), which adjoins a start region and/or end region, in which no cutters, teeth or blades are arranged. On the conveying screw, continuous cutters, teeth and blades can be used respectively alone or in any desired combination.
“Continuous cutters” extend substantially over the entire length of the conveying screw or respectively over the entire length of a comminution region. In particular, the continuous cutters can run helically or axially. A plurality of continuous cutters can be distributed over the circumference of the conveying screw, or the conveying screw has only one continuous cutter. On rotation of the conveying screw, the continuous cutters are moved substantially transversely to their longitudinal extent, or respectively the rotation of the conveying screw brings about a movement with such a transverse component. The separation of the plastic particles therefore takes place principally by shearing.
“Teeth” can be regarded as interrupted cutters or cutters with gaps. Their cutters can also run helically or axially and their cutters are also moved transversely to their longitudinal extent on rotation of the conveying screw. The separation of the plastic particles therefore takes place principally by shearing and tearing.
“Blades” have no distinct axial extent, and their cutters extend substantially radially outwards. On rotation of the conveying screw, the cutters are again moved transversely to their longitudinal extent, the plane of the “blade back”, however, stands substantially in a normal manner onto the rotation axis of the conveying screw. The separation of the plastic particles takes place principally by cutting.
Generally, an exact classification of the separation methods is scarcely possible, in particular when the cutters are not aligned precisely axially or precisely radially. Generally, the plastic particles are therefore comminuted by shearing and tearing and cutting.
Finally, it is favourable if in the region of the conveying screw, fixed counter cutters/counter blades/counter teeth are arranged, cooperating with its continuous cutters/blades, teeth (in particular in the comminution region thereof). Thereby, the cutting performance of the conveying screw is improved. In particular with the provision of blades and counter blades, the separation of the plastic particles no longer takes place necessarily predominantly by cutting, but rather, if applicable, also by shearing.
At this point, it is noted that the variants disclosed with regard to the device for processing thermoplastic material, and advantages resulting therefrom, also refer correspondingly to the embodiments of the operating method according to the invention, and vice versa.
For a better understanding of the invention, the latter is explained in further detail with the aid of the following figures.
There are shown respectively in highly simplified, diagrammatic illustration:
By way of introduction, it is to be stated that in the variously described embodiments, the same parts are provided with the same reference numbers or respectively with the same component designations, wherein the disclosures contained in the entire description can be transferred correspondingly to identical parts with identical reference numbers or respectively with identical component designations. The location indications selected in the description, such as e.g. above, below, lateral etc., refer to the directly described and illustrated figure and, with a change of location, are to be transferred correspondingly to the new location.
In addition to the components which have already been mentioned, the device 1a has a tempering device 7 arranged in the course of the conveying screw 3. Thereby, the conveying screw 3 or respectively the plastic particles conveyed therewith can be temperature-controlled during the conveying. Depending on the configuration of the tempering device 7, heat can be supplied to or removed from the plastic particles via the tempering device 7, whereby these are heated or cooled accordingly.
The tempering device 7 can be formed by a heating device, a cooling device or a combined heating and cooling device. Furthermore, the temperature device 7 can be operated by electrical current or by a heat carrier. In the case of operation by current, the tempering device 7 can be configured in particular as a heating coil. If the tempering device 7 is operated with a heat carrier, it can have, for example, a coiled tube which is flowed through by the heat carrier, which can be gaseous or liquid and can heat or cool the tempering device 7.
In
In
Generally, the supply and/or removal of heat is adjustable. For example, for this, the current which flows through a heating coil of the tempering device 7 can be adjustable, for instance with the aid of a transistor or thyristor. The adjusting of voltage and/or current of an electrical energy source connected to the heating coil would of course also be possible. If the operation with a liquid or gaseous heat carrier is provided, then the inflow to the tempering device 7 can be adjustable with the aid of a valve, which is connected into the flow or return, or else via the adjusting of an output of a pump or of a compressor, which is connected in circuit of the heat carrier. It is also conceivable that the heat carrier can be directed in an adjustable manner via a bypass. Additionally or alternatively, provision can also be made that the temperature of the heat carrier can be adjusted via a heat exchanger of a heating or cooling circuit, which is not illustrated.
Consequently, the said transistor/thyristor, the adjustable electrical energy source, the said valve, the pump/the compressor, or also the said heat exchanger can form influencing means of the tempering device 7, which are connected for example to the outlet of the open loop control/closed loop control 9 and accordingly are actuated by the open loop control/closed loop control 9.
In the example illustrated in
Through the above-mentioned variant of the device 1 a, a representative for the case designated by “a” is realized. This means that at least one temperature sensor 8 is arranged in the course of the conveying screw 3 and/or in the course of the extruder 4, and means for influencing the tempering device 7 and an open loop control/closed loop control 9 connected with the at least one temperature sensor 8 and with the influencing means of the tempering device 7 are provided.
In the example which is shown, the temperature sensor 8 is in practical terms arranged in the transport direction of the conveyed plastic particles after the tempering device 7. In this way, a presettable (set-point) temperature of the plastic particles delivered to the extruder 4 can be regulated and can thereby be maintained particularly well.
Basically, however, it is also possible that the temperature sensor 8 is arranged before the tempering device 7 in transport direction. In this case, for example, a control can be provided for the tempering device 7, which controls the power of the tempering device 7 by means of the temperature of the delivered plastic particles. It is also conceivable that temperature sensors 8 are arranged before the tempering device 7 and after the tempering device 7.
Through the proposed provisions, a set-point temperature can be reached with a high degree of reliability in the extruder 4 and/or at the inlet of the extruder 4. By means of the tempering device 7, material supplied to the extruder 4 can be heated, for example when this has been delivered with a very low temperature and/or has a high thermal capacity and/or has a high melting temperature, and/or has not been heated in the expected manner through friction, shearing work and compression in the conveying tube. In particular, however, it is also conceivable that the plastic particles which are fed to the extruder 4 are cooled by means of the tempering device 7, for example when material has been delivered at a very high temperature and/or has a low thermal capacity and/or has a lower melting temperature and/or has been heated excessively by friction, shearing work and compression in the conveying tube.
Through the said variant of the device 1b, a representative is realized for the case designated by “b”. This means that means 10 for detecting a load of a drive 6 of the extruder 4, means for influencing the tempering device 7 and a closed loop control 9 connected to the detection means 10 and to the influencing means are provided.
To determine the load of the extruder 4, the detection means 10 can be configured as a sensor for measuring a rotation speed of the drive 6 of the extruder 4 (e.g. as a digital incremental encoder), as a sensor for measuring a current received by this drive 6 (e.g. as a voltage meter on a current-sensing resistor), or as a sensor for measuring the torsion of a shaft in the drive 6 (e.g. as a measuring bridge with strain gauge). When the rotation speed of the drive 6 decreases, the current received by the drive 6 increases, or the torsion of a shaft in the drive 6 increases, this is an indication of a more intensive load of the extruder 4.
At this point, it is pointed out that the drive 6 is not necessarily solely a motor, but rather the drive 6 can also, for example, have a gear unit. The above-mentioned rotation speed and the above-mentioned torsion can therefore also be taken at a component in the gear unit.
In the device 1c in particular also the drive motor 5 of the conveying screw 3 is connected to the control unit 9 and is integrated into the open loop control/closed loop control of the device 1c. For example, the rotation speed of the conveying screw 3 can be lowered when load of the extruder 4 increases and vice versa, in particular synchronously to an increase of the temperature.
In contrast to
It can also be seen from
In the examples shown hitherto, the conveying screw 3 is aligned in horizontal direction and the transfer opening B is aligned in vertical direction. This is, indeed, advantageous, but is not compulsory. Generally, it is of course also conceivable that the conveying screw 3 and/or the cross-section of the transfer opening B are aligned obliquely.
Generally, it is also advantageous if the conveying screw 3 has radially arranged cutters, blades or teeth. In this way, the material which is conveyed into the conveying screw 3 can be further comminuted before it reaches the extruder 4. The conveying screw 3 can therefore also be regarded (partly) as a processing drum/comminution screw, or can respectively include this function.
In contrast to
The fixed cutters 17 can be configured, for example, as axially aligned cutters (see also the front view B) or else likewise can run helically (see the front view C). It is particularly advantageous if the pitch of the fixed helical cutters 17 is different to that of the cutters 16 of the conveying screw 3, because then load peaks in the drive torque are prevented. The helical cutters 17 can be wound in the same direction as the cutters 16 of the conveying screw 3 or else in the opposite direction thereto. Finally, it would also be conceivable that the fixed cutters 17 stand in a normal manner to the axis of the conveying screw 3.
Generally, it is advantageous if the fixed cutters 17 are arranged only in the upper and in the lateral region of the conveying screw 3, because in this way it is prevented that material collects in the lower region of the conveying screw 3, which material is not transported away. In addition, the tube in which the conveying screw 3 runs tapers in a funnel shape, whereby the drawing in of the plastic particles into the conveying screw 3 is promoted. Of course, the said eccentric configuration and/or the said funnel-shaped structure is also suitable for the teeth 12 and blades 14 illustrated in
In this variant, the temperature at the temperature sensor 8 is therefore not only regulated, but also it is established which set value is to be taken as the basis for the control. Basically, various sensors 18 can be used for detecting the type/sort of the plastic. For example, it can operate according to the principle of spectral analysis. Under certain circumstances, a continuous determining of the type/sort of the plastic is not possible or is only possible to a restricted extent owing to the required measurement time. It is therefore also conceivable that the measurement is carried out at the start of a batch, and the result forms the basis of the following processing.
Through the proposed provisions, the most varied of materials can be processed in an advantageous manner. This is advantageous in particular in connection with devices 1f, which are used for the recycling of plastic, because there a particularly large number if different plastics accumulate. Often, it is not even known which plastic or respectively which plastic mixtures are to be processed. However, by the use of the above-mentioned sensor 18, the type/sort of the processed plastic can be established and the device if can be adjusted thereto.
In the presented variant, control can take place generally, as stated above, by means of the set-point temperature in the extruder 4 and/or at the inlet of the extruder 4, when in the course of the conveying screw 3 and/or in the course of the extruder 4 a temperature sensor 8, 8a, 8b is arranged (case a). Additionally or alternatively, control can also take place by means of a set-point load of the drive 6 of the extruder 4 when means 10 are provided for detecting a load of the drive 4 of the extruder 6 (case b).
Alternatively or additionally to the sensor 18, input means 21 can also be provided for inputting the type/sort of the processed plastic, as is illustrated in
In addition to the above statements, it is also noted that in the memory 19 also an allocation between the type/sort of a plastic and a set-point temperature profile along at least a portion of the transport course of the plastic particles, containing the set-point temperature in the extruder 4 and/or at the inlet of the extruder 4, can be stored. In addition, further open loop control circuits/closed loop control circuits can be provided in the transport course of the plastic particles, by which the temperature of the plastic particles is able to be influenced, and into which the said set-point temperature profile or parts thereof are able to be loaded.
In this variant, therefore, not only a single set-point temperature is prescribed selectively, but rather a set-point temperature profile along at least a portion of the transport course of the plastic particles, which leads at least through the conveying screw 3 and the extruder 4. Thereby, the device if can be adjusted even better to the type/sort of the processed plastic.
In particular, the temperature of the plastic particles, depending on the type/sort, in the entire transport course thereof up to a position in the extruder 4, can be
In practical terms, the temperature profiles for four different materials M1 . . . M4 are presented. For the materials M1 and M2, the temperature T is rising constantly in the entire transport course up to position E. These profiles are suitable in particular for plastics to which relatively little energy is supplied through friction in the conveying screw 3, or respectively plastics which have a comparatively high melting point. For example, for the material M1 polyethylene terephthalate (PET) can be provided, and polyamide (PA) for the material M2.
For the materials M3 and M4, the temperature T is rising constantly in the entire transport course up to the position E, but is falling in the course of the conveying screw 3. These profiles are suitable in particular for plastics to which a relatively large amount of energy is supplied through friction in the conveying screw 3, or respectively plastics which have a comparatively low melting point. For example, polyolefin can be provided for the material M3, and ethylene vinyl acetate (EVA) for material M4.
The materials M3 and M4 are therefore cooled by the tempering device 7 in the course of the conveying screw 3, in order to prevent or at least reduce a clogging or sticking of the extruder opening D or respectively a sticking of the plastic particles thereon. In this connection, it is also advantageous in particular if a cooling power of the tempering device 7 is greater than a power supplied to the plastic particles in the conveying screw 3 through friction. In a further preferred variant, the cooling power of the tempering device 7 is greater than a drive power of the conveying screw 4. The latter is generally easier to determine than a power supplied to the plastic particles in the conveying screw 4 through friction, whereby also the dimensioning of the tempering device 7 is simplified. A slight oversizing which has possibly taken place thereby can serve as security.
In the present example, reference was made to a transport path up to the position E. Starting from this position E, the temperature T no longer increases up to the nozzle F. However, it is also conceivable that the temperature T also increases from the position E up to the nozzle F. In this case, the above considerations apply for the entire transport path of the plastic particles through the device 1g.
In the above example, the presented method is carried out on the basis of a set-point temperature profile and with the aid of several temperature sensors 8, 8a, 8b arranged in the transport course of the plastic particles. Generally, however, it is also conceivable that the addressed method is carried out in an analogous manner alternatively or additionally by means of a set-point load profile. This is possible in particular when several drive motors are integrated into the transport course of the plastic particles. In the illustrated examples, these are the first drive 5 for the conveying screw 3, the second drive 6 for the extruder 4 and the motor 23 for comminution shaft/blade shaft 22. However, it would also be conceivable that the melting of the plastic particles takes place in several extruder stages, driven independently of one another, or the transport of the plastic particles is provided by several conveying screws 3 driven independently of one another. In this case, the set-point loads of these drives can also be integrated into the set-point load profile.
The example embodiments show possible variant embodiments of a device 1a . . . 1g for processing thermoplastic material, and methods for their operation, wherein at this point it is noted that also various combinations of the individual variant embodiments with one another are possible.
In particular, it is pointed out that the presented control principles are not necessarily linked to the mechanical characteristics of the structural form of the device 1a . . . 1g which was selected for illustration. This means that the examples are exchangeable with one another with regard to their characteristics concerning control technique, and as regards their mechanical structure. For example, the control principle presented in
In particular, it is noted that a device 1a . . . 1g in reality can also comprise more or fewer components than are illustrated.
Finally, for the sake of good order, it is also pointed out that for a better understanding of the structure of the device 1a . . . 1g, the latter, or respectively its components, have partly been illustrated not to scale and/or enlarged and/or reduced in size.
The problem forming the basis of the independent inventive solutions can be taken from the description.
| Number | Date | Country | Kind |
|---|---|---|---|
| A 51001/2015 | Nov 2015 | AT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/078622 | 11/24/2016 | WO | 00 |
