DE102009034565B4 - Heating and cooling device for an extruder cylinder and method for its operation - Google Patents

Abstract

Heating and cooling device (2) for an extruder cylinder (3) for discharging a plastic compound with several heating and cooling sections (1) arranged one behind the other in the longitudinal direction of a cylinder jacket (4) of the extruder cylinder (3), each with heating and cooling section (1) several, arranged in a housing (7), the extruder cylinder (3) as half-shell elements, a heating element (22) and a cooling element (17) having, upper and lower heating and cooling devices (24, 25) and with a with a target Temperature control device (47) of a system control and regulating device (40) connected to a temperature sensor (35) and with temperature detection means (33) for detecting the temperature of the cylinder jacket (4) and with a cooling air fan connected to the system control and regulating device (40) ( 10), characterized in that at least the heating elements (22) of the upper heating and cooling devices (24) have a temperature difference control device in a line (41) (53) is arranged upstream with a power control means (46) and a temperature difference value transmitter (56) of the temperature difference control device (53) is wired to the target temperature control device (47) and the temperature detection means (33).

Description

The invention relates to a heating and cooling device as described in the preamble of claim 1 and a method for operating the heating and cooling device as described in the preamble of claims 13 and 14.

From the document AT 003 319 U1 a method for regulating the temperature of a plastic mass in an extruder cylinder is known. According to this method, heat is supplied to the extruder cylinder via heating devices which are arranged on the outer circumference and the internal temperature of the extruder cylinder is measured by a first temperature sensor and is kept at a predetermined setpoint by a controller. In addition, a temperature measurement is carried out on a surface of the extruder cylinder and this measured outside temperature is taken into account as a correction variable when regulating the inside temperature, the controller having a self-learning control algorithm in order to prevent the inside temperature from overshooting as far as possible and to limit the outside temperature to a predetermined maximum value. wherein the additional temperature sensor is provided in the lower region of the extruder cylinder, and the heating power of the section of the heater arranged on the lower side is designed to be greater than that acting on the upper side of the extruder cylinder.

From another document, EP 0 744 272 B1 , is an extruder cylinder comprising a plurality of block cylinders lined up and divided into an upper block and a lower block, the block cylinders being arranged along a horizontal axis and forming a cylinder. The upper block and the lower block are provided with heating units and cooling units and with temperature detecting means for detecting a temperature of the upper block and a temperature of the lower block. The temperature of the upper block and the lower block are individually controllable in terms of temperature, whereby under normal operating conditions the upper and lower blocks are regulated in terms of temperature under the same condition, whereas when the cylinder is disassembled a temperature of the upper block below the temperature of the lower one Block is lowered.

The object of the invention is to create a heating and cooling device with which small temperature differences in an extruder cylinder can be maintained with a high degree of constancy of a predetermined target temperature.

This object is achieved with a device with the features of claim 1. The surprising advantage here is that a balanced cylinder temperature is achieved with little system and control effort and a subsequent upgrade of an existing system is inexpensive and thus economically feasible.

However, a further development as described in claim 2 is also advantageous, since a very small temperature difference range is ensured even with a very long temperature difference range by a setpoint temperature control in addition to ordered temperature difference control with the splitting of the power control of upper and lower heating and cooling devices Extruder cylinders, both in a heating, cooling and temperature holding phase, is achieved. The advantageous development described in claim 3 achieves instant switching on and off of the power supply.

Advantageous further developments are also given in claims 2 to 12, whereby the heating and cooling device according to the invention can be designed for the very diverse required power ranges and also for retrofitting without significant interventions in existing system control and regulation devices and thus without high Setup and assembly effort can be used.

Furthermore, the implementation of changed control parameters is achieved through the use of a processor, whereby program changes are simplified and such systems can be used more flexibly and process and investment costs are often saved.

The object of the invention is also to provide a method for operating a heating and cooling device for an extruder cylinder with which the lowest possible heat difference and minimal deviation from a predetermined target temperature is achieved in the mass flow conveyed through an extruder cylinder.

This object of the invention is achieved by the measures given in claim 13. The surprising advantage here is that a method for avoiding cylinder deformation can also be retrofitted to existing systems by simple measures.

The object of the invention is also achieved by the measures given in claim 14 with which a splitting of the power control of upper and lower heating and cooling devices is ensured, whereby a very small temperature difference range in the extruder cylinder in both heating, cooling and temperature - Holding phase is reached. With that it is possible a to effectively avoid damaging cylinder deformation even with very long extruder cylinders.

For a better understanding of the invention, it is explained in more detail with reference to the following figures.

• 1 einen Teilbereich eines Extruderzylinders mit der erfindungsgemäßen Heiz- und Kühleinrichtung, teilweise geschnitten;
• 2 die Heiz- und Kühleinrichtung an einem Extruderzylinder geschnitten gemäß den Linien II-II in 1;
• 3 ein Funktionsschaltbild der erfindungsgemäßen Heiz- und Kühleinrichtung in vereinfachter Darstellung;
• 4 ein Temperaturverlaufsdiagramm bei einer beispielsweisen Regelungscharakteristik der erfindungsgemäßen Heiz- und Kühleinrichtung;
• 5 eine andere Ausbildung der erfindungsgemäßen Heiz- und Kühleinrichtung in vereinfachter Darstellung.

They each show in a greatly simplified representation:

• 1 a partial area of an extruder cylinder with the heating and cooling device according to the invention, partially in section;
• 2 the heating and cooling device on an extruder cylinder cut according to lines II-II in 1 ;
• 3 a functional diagram of the heating and cooling device according to the invention in a simplified representation;
• 4th a temperature profile diagram with an exemplary control characteristic of the heating and cooling device according to the invention;
• 5 another embodiment of the heating and cooling device according to the invention in a simplified representation.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference symbols or the same component names, whereby the disclosures contained in the entire description can be transferred accordingly to the same parts with the same reference symbols or the same component names. The location details chosen in the description, such as Top, bottom, side, etc. refer to the figure immediately described and shown and are to be transferred accordingly to the new position in the event of a change in position. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

All information on value ranges in the objective description are to be understood in such a way that they include any and all sub-areas, e.g. the information is 1 to 10 to be understood as meaning that all sub-areas, starting from the lower limit 1 and the upper limit 10 are included, ie all subranges begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, for example 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

In the 1 and 2 is in detail one of several heating and cooling sections 1 a heating and cooling device 2 , an extruder barrel 3 comprehensive, shown. Depending on the performance of an extruder, there are different dimensions in the diameter and length of the extruder cylinder 3 in action. According to the performance requirements and dimensions, heating and cooling devices are also adapted in terms of dimensions and performance 2 required. The heating and cooling devices are in accordance with these technical specifications 2 in heating and cooling sections 1 subdivided, whereby economically to manufacture sizes can be achieved.

The heating and cooling device shown and described in detail below 2 , using the example of the heating and cooling section 1 , represents a possible embodiment.

The extruder barrel 3 is preferably made of one, a cylinder jacket 4th forming thick-walled pipe 5 and a thin-walled tube made of high-strength steel drawn into it 6th educated. This means an economical solution for the extruder barrel 3 with high durability, of course, this is not a mandatory solution, as it is of course also possible to use the extruder barrel 3 to be formed in one piece from a high-quality steel tube.

In detail, one of the heating and cooling sections is now shown 1 as it is shown in section, described. The extruder barrel 3 surrounds a split housing made of sheet metal 7th with openings 8th in a base plate 9 . The openings 8th form inflow channels for a cooling air flow from a cooling air fan 10 , which via an air guide housing 11 on the base plate 9 is attached. The openings 8th are via gravity operated and by air flow - according to arrows 12 - hinged flaps that can be activated in the open position 13 towards an interior 14th of the housing 7th covered. In the case of the operation of the cooling air fan 10 give the flaps 13 the openings 8th free or they become free when the cooling air fan is at a standstill 10 locked. The base plate 9 opposite are in the housing 7th several areas with outflow openings, e.g. grille areas 15th , for the exit of the cooling air flow - according to the arrows 12 - intended.

In that of the housing 7th delimited interior 14th are, as known from the prior art, formed with an approximately U-shaped cross-section cooling elements 17th , preferably made of a material with good thermal conductivity, for example copper sheet, aluminum sheet or the like, arranged with a base leg 18th on a surface 19th of the extruder barrel 3 close fitting and at right angles protruding side legs 20th as cooling flags 21st are trained. By training the side thighs 20th as cooling lugs separated from one another by incisions 21st that are slightly twisted in their protruding length, for example, there is a high level of heat dissipation from the cylinder jacket as soon as the cooling air flow takes effect 4th reached as required for rapid temperature control.

Between the cooling fins 21st of the cooling element 17th are on the base leg 18th adjacent heating elements 22nd arranged as they are also known from the prior art. These consist of ceramic link belts 23 which have bores or grooves running in the circumferential direction in which heating coils made of electrical resistance wire are arranged.

One cooling element each 17th with the heating element 22nd forms on the extruder barrel 3 as a half-shell section, an upper and lower heating and cooling device 24 , 25th out.

Preference is given to the half-shell sections which extend in a horizontal axis through a longitudinal center axis 26th of the extruder barrel 3 extending plane 27 are divided by means of the heating elements 22nd comprehensive straps 28 on the extruder barrel 3 attached.

As can be seen in the figures, the heating and cooling sections are in 1 , e.g. four pairs of from the cooling element 17th and heating element 22nd formed half-shell sections in the longitudinal direction of the extruder cylinder 3 on its surface 19th attached, each two of the paired arrangement with a small side distance 29 are arranged and a space in the middle 30th by a larger side distance 31 between opposing cooling vanes 21st is formed.

In this space 30th are on the outer circumference of the extruder cylinder 3 , with sensing elements 32 on the surface 19th of the cylinder jacket 4th adjacent, in the twelve and six o'clock positions, temperature detection means 33 arranged, that is, that these each have approximately vertices 34 the heating and cooling devices 24 , 25th assigned. This training with the temperature detection means 33 is identical in each heating and cooling section 1 intended.

For monitoring and regulating the temperature inside the extruder cylinder 3 and thus the plastic mass to be conveyed is standard in such systems on the extruder cylinder 3 , in an area outside the heating and cooling sections 1 at least one, preferably several temperature sensors 35 provided at any point on the circumference.

These temperature sensors 35 suffice with a sensing element 36 to close to an inner surface 37 of the extruder barrel 3 approach the internal temperature of the extruder cylinder as precisely as possible 3 and thus to measure the temperature in a mass flow, for example the plastic mass.

Two of these are preferred as standard for temperature detection and temperature control 2 such temperature sensors 35 distributed over a length of the extruder cylinder 3 intended.

How on that 2 it has to be taken from the physically conditioned heat flow in the extruder jacket 4th From a lower area to an upper area proved to be advantageous, the cooling element 17th the lower heating and cooling device 25th in an area of the vertex 34 without cooling flags 21st to train. A center angle is advantageously 38 in which no cooling plumes 21st are provided, about 60 ° to 90 °.

In the 3 is a simplified representation of a functional diagram of the heating and cooling device 2 using the example of a heating and cooling section 1 with the upper heating and cooling device 24 and the lower heating and cooling device 25th and the cooling fan on the extruder barrel 3 shown.

The energy supply for a heating and cooling phase to the heating elements 22nd the heating and cooling devices 24 , 25th and that of each heating and cooling section 1 associated cooling air fan 10 takes place via one with an energy network 39 Wired system control and regulation device 40 as it is provided as standard for the operation of an extrusion line. Via lines 41 , 42 the heating elements are separated 22nd the upper and lower heating and cooling device 24 fed. Via a line 43 is the cooling air fan 10 with the system control and regulation device 40 connected.

The temperature sensor 35 is with the sensing element 36 until close to the inner surface 37 of the extruder barrel 3 reaching outside the heating and cooling section 1 on the cylinder jacket 4th arranged and over a line 44 with the system control and regulation device 40 connected. This temperature sensor 35 is used to record the temperature of a mass flow 45 in the extruder barrel 3 and thus the control of the target temperature by means of a power control means 46 a target temperature control device 47 . There are often several such temperature sensors 35 , over a length of the extruder barrel 3 distributed, provided.

In order to prevent the set temperature from exceeding a tolerance limit, and to allow the heating and cooling device to react quickly 2 As already described, every heating and cooling section can be reached 1 assigned that over the line 43 with the plant control and Control device 40 connected cooling air fan 10 intended.

The plant control and regulation device 40 regulates via the capacity control means 46 , depending on the specified target temperature and by means of the target temperature control device 47 , based on the temperature sensor 35 recorded temperature values, the heating and cooling equipment 2 , ie the application of energy to the heating elements in a heating phase 22nd the heating and cooling devices 24 , 25th or the application of energy to the cooling air fan in a cooling phase 10 .

As already described with reference to the previous figure, there are heating and cooling sections 1 , the vertices 34 assigned, the temperature detection means 33 with on the surface 19th of the cylinder jacket 4th adjacent sensor elements 32 , for recording the temperatures in an upper and a lower area of the cylinder jacket 4th arranged and over lines 48 , 49 with one for the system control and regulation device 40 via comparator switch switches 50 and another power control means 51 and management 52 preferably external temperature difference control device connected in parallel 52 connected. By the power control means 46 , 51 a differentiated power control for the upper and lower heating elements 22nd by specifying a temperature difference, for example a temperature difference range between 3 ° and 5 °, achieved by the comparator switch 50 the priority between the target temperature control device 47 and the temperature difference control device 52 is determined. This is done, for example, by a processor 54 in the target temperature control device 47 and a target temperature control element 55 and a temperature differential encoder 56 the temperature difference control device 47 .

This ensures exact regulation of the set temperature T (s) and thus harmful temperature fluctuations in the mass flow 45 which can lead to a loss of quality, as well as an exact temperature difference control within small tolerance limits between the upper and lower area of the extruder cylinder 3 is achieved, causing warping of the extruder barrel 3 can be effectively avoided through different thermal expansions in the upper and lower cylinder area and the resulting higher wear of the cylinder and a screw.

It is also pointed out that the temperature difference control device 52 also in the system control and regulation device 40 or in the setpoint temperature control device 55 can be arranged integrated.

Using the in 4th The temperature curves shown for an upper area T (o) and a lower area T (u) of the extruder cylinder are the control characteristics of the heating and cooling device 2 for a heating, holding and cooling phase explained below.

Due to the physically determined heat flow, T (o) is higher than T (u) and thus a temperature range is established, whereby in the ideal case a target temperature T (s) is set approximately between T (o) and T (u) and the material must be specified for the processing of a plastic compound. This

Again 4th It can also be seen that with increasing T (s), e.g. during a heating phase, the temperature band shifts in the direction of the upper area of the extruder cylinder and this would result in a temporary increase in the set temperature T (s) and a temperature difference DT = T (o) - T (s) greater than for reasons as already stated above, occur - as can be seen from the curve progressions shown in solid lines and the dotted lines.

In the cooling phase, the direct action of the cooling air flow from the cooling air fan in the lower cylinder area causes a rapid decrease in temperature T (u), while a delayed decrease in temperature T (o) in the upper cylinder area also results in a temperature difference DT that is temporarily greater than intended a - as also conveyed by the curves shown for T (o) and T (u).

Through the training of the heating and cooling device 2 as in the previous 1 to 3 is described in detail, by the detection of the temperature profiles T (o) and T (u) by means of the temperature detection means 33 and the one with the power regulator 46 connected temperature differential control device 53 , for a given target temperature T (s) the power control, at least for each heating and cooling section 1 , the heating elements 22nd the upper heating and cooling device 24 and the lower heating and cooling device 25th , regulated differently for the temperature curves T (o) and T (u). The control algorithm of the temperature difference control device 53 is designed for this in the heating phase and in the holding phase, depending on the specified target temperature level, the output via the output control means 46 for the heating element 22nd of the upper heating and cooling devices 24 versus the power for the heating element 22nd the lower heating and cooling devices 25th to regulate back whereby the specified temperature difference DT is maintained.

In the cooling phase, the lower heating and cooling devices are acted upon directly 24 with the cooling air flow in the lower area of the extruder barrel 3 one across from the top of the extruder barrel 3 faster heat extraction, whereby in this case too the temperature difference DT would temporarily exceed a predetermined value, as has already been mentioned. This is also due to the differentiated power control of the upper and lower heating and cooling devices 24 , 25th balanced in that the heating elements also in the cooling phase 22nd the lower heating and cooling devices 25th corresponding to the specified control algorithm are temporarily charged with power and thus the specified temperature difference DT is maintained. In the 5 is another embodiment of the heating and cooling device according to the invention 2 with the extruder barrel 3 , in the form of the upper and lower heating and cooling device comprising half-shells 24 , 25th , in a simplified representation with the heating elements 22nd shown. The power control of the heating elements 22nd takes place from the system control and regulation device 40 over the line 42 to the lower heating element 22nd and the line 41 to the upper heating element 22nd .

The extruder barrel 3 is with the up close to the inner surface 37 approaching temperature sensor 35 provided that over the line 44 with the target temperature control device 47 the system control and regulation device 40 is line-connected. Preferably in the area of the upper apex 34 is that in the cylinder jacket 4th with the sensing element 32 into a recess 57 low protruding temperature detection means 33 arranged that over the line 48 directly with the temperature difference value transmitter 56 the temperature difference control device 53 connected is. Via a line 58 we the temperature difference value transmitter 56 the temperature reading from the temperature sensor 35 from the setpoint temperature control device 47 forwarded. In the temperature differential value transmitter 56 is based on the temperature readings received in real time from the temperature sensor 35 and the temperature detecting means 33 the temperature difference is determined and in a comparator circuit 59 of the temperature differential value transmitter 56 compared with a predetermined, adjustable temperature difference value.

According to this embodiment, the temperature difference in the extruder cylinder is provided for the temperature difference control 3 to be regulated by switching the upper heating element on and off because of the physical conduction of heat in the extruder jacket 4th the upper area always has the higher temperature. The line is provided for this 41 for energy control of the upper heating element 22nd about the heating element 22nd upstream power control means 46 , for example a switch-on means 60 to carry out that for the corresponding switching states "On" or "Off", depending on the temperature difference value by an adjusting means 61 the temperature difference control device 53 is applied.

In this way, when the predetermined temperature difference value is exceeded, for example a range between 5 ° and 15 ° has proven advantageous, the power supply to the heating element 22nd the upper heating and cooling device 24 interrupted until the temperature difference value specified as the maximum is reached or undershot.

The exemplary embodiments show possible design variants of the heating and cooling device 2 , whereby it should be noted at this point that the invention is not limited to the specifically illustrated design variants of the same, but rather various combinations of the individual design variants with one another are possible and this possibility of variation due to the teaching of technical action through the present invention in the ability of the technical Area of active professional lies. All conceivable design variants that are possible through combinations of individual details of the embodiment variants shown and described are therefore also included in the scope of protection.

For the sake of clarity, it should finally be pointed out that, for a better understanding of the structure of the heating and cooling device, these or their components have been shown partially not to scale and / or enlarged and / or reduced.

The task on which the independent inventive solutions are based can be found in the description.

Above all, the individual in the 1 , 2 ; 3 and 5 The embodiments shown form the subject of independent solutions according to the invention. The related, inventive tasks and solutions can be found in the detailed descriptions of these figures.

List of reference symbols

1

Heating and cooling section

2

Heating and cooling equipment

3

Extruder barrel

4th

Cylinder jacket

5

pipe

6th

pipe

7th

casing

8th

opening

9

Base plate

10

Cooling air housing

11

Air guide housing

12

arrow

13

flap

14th

inner space

15th

Grid area

16 17

Cooling element

18th

Base leg

19th

surface

20th

Side thighs

21st

Cooling vane

22nd

Heating element

23

Link belt

24

Heating and cooling device

25th

Heating and cooling device

26th

Longitudinal central axis

27

level

28

Tension band

29

Side spacing

30th

Space

31

Side spacing

32

Sensing element

33

Temperature sensing means

34

Vertex

35

Temperature sensor

36

Sensing element

37

Inner surface

38

Center angle

39

Energy network

40

Plant control and regulation device

41

management

42

management

43

management

44

management

45

Mass flow

46

Power control means

47

Target temperature control device

48

management

49

management

50

Comparator switch

51

Power control means

52

management

53

Temperature differential control device

54

processor

55

Target temperature control element

56

Temperature differential value transmitter

57

Recess

58

management

59

Comparator circuit

60

On / off means

61

Adjusting agent

Claims (14)

Heating and cooling device (2) for an extruder cylinder (3) for discharging a plastic compound with several heating and cooling sections (1) arranged one behind the other in the longitudinal direction of a cylinder jacket (4) of the extruder cylinder (3) with each heating and cooling section (1) several, arranged in a housing (7), the extruder cylinder (3) as half-shell elements, a heating element (22) and a cooling element (17) having, upper and lower heating and cooling devices (24, 25) and with a with a target Temperature control device (47) of a system control and regulating device (40) connected to a temperature sensor (35) and with temperature detection means (33) for detecting the temperature of the cylinder jacket (4) and with a cooling air fan connected to the system control and regulating device (40) ( 10), characterized in that at least the heating elements (22) of the upper heating and cooling devices (24) have a temperature difference control device in a line (41) g (53) is arranged upstream with a power control means (46) and a temperature difference value transmitter (56) of the temperature difference control device (53) is line-connected to the target temperature control device (47) and the temperature detection means (33). Heating and cooling device (2) after Claim 1 , characterized in that two temperature detection means (33) connected to the temperature difference control device (53) are arranged in the heating and cooling section (1) and the temperature difference control device (53) and the target temperature control device (47) via comparator switch gates (50) ) with the power control means (46) for the heating elements (22) of the upper heating and cooling devices (24) and another Power control means (51) for the heating elements (22) of the lower heating / cooling devices (25) are line-connected. Heating and cooling device (2) after Claim 1 , characterized in that the power control means (46, 51) is formed by on-off switching means. Heating and cooling device (2) after Claim 1 , characterized in that the power control means (46, 51) are arranged in the temperature difference control device (53). Heating and cooling device (2) after Claim 1 , characterized in that the power control means (46, 51) are arranged in the setpoint temperature control device (47). Heating and cooling device (2) after Claim 1 , characterized in that a processor (54) with a set temperature control element (55) and the temperature difference value transmitter (56) is arranged in the set temperature control device (47). Heating and cooling device (2) after Claim 1 , characterized in that the processor (54) with the temperature difference value transmitter (56) is arranged in the temperature difference control device (53). Heating and cooling device (2) after Claim 1 , characterized in that the setpoint temperature control device (47) with the comparator switch (50) and the power control means (46, 51) is arranged in the plant control and regulation device (40). Heating and cooling device (2) after Claim 1 , characterized in that the temperature difference control device (53) is arranged in the plant control and regulating device (40). Heating and cooling device (2) according to one of the preceding claims, characterized in that the temperature detection means (33) are arranged on apexes (34) of the heating and cooling devices (24, 25) on the extruder cylinder (3) and on a surface (19) of the cylinder jacket (4) are arranged adjacent. Heating and cooling device (2) according to one of the preceding claims, characterized in that sensor elements (32) of the temperature detection means (33) protrude into recesses in the cylinder jacket (4). Heating and cooling device (2) according to one of the preceding claims, characterized in that the temperature detection means (33) are arranged in an intermediate space (30) of adjacent heating and cooling devices (24, 25). Method for operating a heating and cooling device (2) for an extruder cylinder (3) for discharging a plastic compound with several heating and cooling sections (1) arranged one behind the other in the longitudinal direction of a cylinder jacket (4) of the extruder cylinder (3), each with heating and cooling sections (1) Preferably several, arranged in a housing (7), the extruder cylinder (3) as half-shell elements, comprising a heating element (22) and a cooling element (17), upper and lower heating and cooling devices (24, 25) and with a with a target temperature regulating device (47) of a plant control and regulating device (40) connected temperature sensor (35) and with temperature detection means (33) for a temperature detection of the cylinder jacket (4) and one with the plant control and regulating device (40) connected cooling air fan (10), characterized in that a real-time temperature detection of the temperature sensor (35) for the target temperature control device (47) and a real-time temperature detection of the temperature detection means (33) for the temperature difference control device (53) in a temperature difference value transmitter (56), a temperature difference value is determined and when a predetermined temperature difference value is exceeded, a control signal for a power control means (46) for power control or power shutdown for at least the heating elements (22) of the upper heating and cooling devices (24) are generated and power is switched on by the power control means (46) as soon as the predetermined temperature difference value is reached or undershot. Method for operating a heating and cooling device (2) for an extruder cylinder (3) for discharging a plastic compound with several heating and cooling sections (1) arranged one behind the other in the longitudinal direction of a cylinder jacket (4) of the extruder cylinder (3), each with heating and cooling sections (1) Preferably several, arranged in a housing (7), the extruder cylinder (3) as half-shell elements, comprising a heating element (22) and a cooling element (17), upper and lower heating and cooling devices (24, 25) and with a with a target temperature regulating device (47) of a plant control and regulating device (40) connected temperature sensor (35) and with temperature detection means (33) for a temperature detection of the cylinder jacket (4) and one with the plant control and regulating device (40) connected cooling air blower (10), characterized in that temperature detection means (33) are arranged on at least two surface areas of the extruder jacket (4) and nd a permanent temperature recording takes place and temperature measured values to a temperature difference control device (53) transmitted and a temperature difference value is formed in a processor (54) and compared with a predetermined difference value and, if the temperature difference value is greater than the predetermined difference value, depending on a control state of the setpoint temperature control device (47) via a temperature difference value transmitter (56) of the temperature Difference control device (53) and via comparator switching points (50) either via a power control means (46) the heating elements (22) of the upper heating and cooling devices (24) and / or via a power control means (51) the heating elements (22) of the lower heating and cooling devices Cooling devices (25) are regulated.

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