DE8712481U1 - Device for regulating heat flows - Google Patents

Description

DiPL*PMYS. DR, WALTHER JUNIUS 3 Hannover WOLFiTKASSE 24 ■ TELEPHONE (Ui ti) Ij Ai Jo

18* August 1987
My file 975

Paul Troester Maschinenfabrik} Am Bfäbrinke 2-4,
3Ö00 Hanover 89

Device for regulating heat flows

The invention relates to a device for controlling

of heat flows that occur in a plastic

and/or rubber processing machinery |

Process between machine part walls and a |

Tempering media run. f

In plastic and/or rubber processing machines |

machines, such as extruders and calenders, parts of the machine that come into contact with the plastic to be processed

and/or rubber, tempered \

they must be adapted to the requirements of the

process or process section heated and/or |

cooled. The tempering medium used here is primarily

Line water is used, which is usually in a circular |

laisf by the processing machine, a cooling device and/or a heating device, from a

Pump is put into circulation, flows. The inlet temperature of the tempering medium is regulated in
the processing machine. From a control point of view, this is simple, but the control requires

It always takes a certain amount of time until the temperature control device is heated to the desired temperature value; when the temperature medium is cooled, this time generally takes even longer. This control system has a considerable amount of inertia.

This control is not sufficient for a number of processes in which high-quality products of consistent quality are to be produced. Other options have therefore been sought and the idea has arisen that a second control variable can be obtained for controlling the heat flow by changing the heat transfer conditions. , If, depending on requirements, a laminar or turbulent flow is used in the process control. This brings us closer to the goal of changing heat flows more quickly and effectively, but also runs the risk of over-controlling more easily and therefore not working accurately enough.

DE-OS 32 34 612 has made it known that in an extruder the parts to be tempered can be divided into several sections. All tempering medium circuits are connected in series here.

The invention avoids the disadvantages of the prior art. The object of the invention is to regulate warm currents with high precision and very short response times using a tempering medium subject to uncontrolled temperature fluctuations.

The invention consists in the fact that the volume flow and the inlet temperature of a tempering medium for

Control of a process temperature

Excessive heat flows are changed very quickly and with high precision to change the volume flow. The changes are possible at a faster speed than by heating or cooling the tempering medium. Since the present invention uses both the volumetric netiOm and the inlet temperature of the tempering medium for control, not only is control very fast, but also very precise. The response times are very short. The effects on the tempering medium by cooling or heating can take place slowly.

In the various processing machines for plastic and/or rubber, not all parts of the machine that come into contact with the material to be processed need to be kept at the same temperature; sometimes even a machine part, such as the screw and/or the cylinder of an extruder, needs to be kept at different temperatures in different processing zones. Here it is useful if the control of several process temperatures is carried out by regulating the volume flow in different tempering zones. It is useful if the individual tempering zones are supplied by a higher-level circuit in which a certain media temperature is regulated.

It is advantageous and structurally simple if the volume flow control in the individual tempering zones is carried out by control valves and if control valves for individual tempering zones in the system are adjusted coupled with a valve in a bypass.

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It is advantageous if the pumping capacity in the overall system is provided by a pump in a transferred circuit.

The device according to the invention for regulating the heat flows which occur during a process carried out in a plastics and/or rubber processing machine between machine part walls and a tempering

J-. medium flow, is characterized by the fact that

Process means for changing the volume flow of the tempering medium are provided, which are controlled by a process

control or a controller depending on the temperature of machine parts and/or the inlet temperature of the tempering medium.

With a standard process control, e.g. operated via a microprocessor, the effort required for this control is very low. With simple means, a shorter response time, a shorter control time and less effort when controlling the temperature of the tempering medium by cooling or heating can be achieved.

It is advisable to design the working equipment for changing the VeC of the volume flows as valves, slide valves and/or working equipment for adjusting the delivery volume of pumps. Valves and slide valves

_b but are quick and easy to set up. The

!> Tools for adjusting the delivery volume of

* Pumps are simple, as they only consist of

speed-adjustable electric motors.

It is advantageous if a plastic and rubber processing machine is assigned different tempering zones, if each tempering zone

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a valve or slide is assigned and if several zones are assigned a pump together. This simplifies the construction effort.

Furthermore, it is advantageous if a bypass is arranged at least parallel to a volume flow regulating the process temperature, if a valve or a slide is arranged in the bypass and if this valve is coupled in the bypass with the control valve for the volume flows, preferably in such a way that closing the volume flow valve is coupled with opening the bypass valve and vice versa. With these working means, the desired control can be carried out very easily and quickly.

It is advantageous if the tempering zones are arranged parallel to each other and are flowed through by parallel volume flows of different strengths and speeds.

The essence of the invention is explained in more detail below using two exemplary embodiments. They show:

Fig. 1 is a block diagram of a pump control, Fig. 2 is a block diagram of a valve control,

Fig. 3 is a block diagram of a valve and bypass control.

The plastic and/or rubber processing machine 1 has three tempering zones 2, 3, 4 in which the machine part walls are to be kept at three different temperatures. The tempering medium flows outside the plastic and/or rubber

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Processing machines through the pipeline 5 into the cooling device 8, then further through the pipeline into the heating device 9, then into the pipeline 7 in the direction of the plastic and/or rubber processing machine. Depending on whether the tempering medium is to be heated or cooled, either the cooling device 8 or the heating device 9 is in operation.

In the embodiment of Fig. 1, the pipeline 7 connected to the heating device 9 is divided into three branches 7A, 7B, 7C assigned to the tempering zones 2, 3, 4. These branches 7A, 7B, 7C run parallel to one another and each lead to one of the tempering zones 2, 3, 4. From these, the used tempering medium flows into the corresponding line branches 5ß, 5B, 5C _; which run parallel to one another and are then brought together in a line branch to the pipeline 5. In each of the line branches 7A, 7B, 7C or 5A, 5B, 5C there is a pump 1OA, 1OB, 1OC. The speed of the drive motors of the pumps 10A, 10B, 10C is determined by the process controller 11, which is connected to the pumps 10A, 10B, 10C via cables 12A, 12B, 12C. The process controller 11 receives as input signals from the measuring points 13A, 13B, 13C the measured wall temperature of the machine part in contact with the material to be processed via cable 15 and additionally from the temperature sensor 14 via cable 16 the inlet temperature of the tempering medium. This can be measured in front of the pumps, as shown in Fig. 1, but it can also be measured for each of the three tempering zones 2, 3, 4 immediately before the tempering medium enters the plastic and/or rubber

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The temperature can be measured in the plastic processing machine using the temperature sensors 14A ₅ 14B, 14C.

In the embodiment of Fig. 2, there are three valves 17A, 17B, 17C with which the volume flow through the tempering zones 2, 3, 4 is controlled. In this embodiment, only a single pump 10 is provided, assigned to the three tempering zones 2, 3, 4. This is located in line 6. The adjustment motors for the valves _17A , 17B, 17C are supplied with the electrical energy required for adjustment by the process controller 11 via the cables 18. In this embodiment, the process controller 11 is controlled by a single temperature sensor 14, which measures the temperature of the tempering medium, and three temperature sensors 13A, 13B, 13C, which measure the wall temperature in the machine or on the machine part.

In the embodiment of Fig. 3, additional bypass lines 19A, 19B, 19C are provided, in which valves 20A, 20B, 20C are arranged. These valves 20A, 20B, 20C in the bypass lines 19A, 19B, 19C are coupled to the valves 17A, 17B, 17C and are each adjusted jointly by a servomotor 21A, 21B, 21C, which is connected to the process controller 11 via a cable 22A, 22B, 22C. The tempering medium can thus be directed either into the tempering zones 2, 3, 4 or into the bypass line 19A, 19B, 19C. The valves are designed and switched in such a way that the more the line 7A, 7B, 7C leading into the tempering zone 2, 3, 4 is closed, the more the bypass line 19A, 19B, 19C is opened.

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Claims (5)

Expectations: 1. Device for regulating heat flows, which run between machine part walls and a tempering medium during a process carried out in a plastic and/or rubber processing machine, characterized, that working means (10, 17, 20) are provided for changing the volume flows of the tempering medium, which are controlled by a process control (11) or a controller depending on the temperature of machine parts and/or the inlet temperature of the tempering medium. 2. Device according to claim 1,
thereby marked with gel, that the working means for changing the volume flows are valves (17), slide valves (20) and/or working means for adjusting the delivery volume of pumps (10). 3. Device according to claim 1,
characterized, that different tempering zones (2,3,4) are assigned to a plastic and/or rubber processing machine (1), that each tumbling zone (2,3,4) is assigned a valve (17) or slider (20) and that a pump (10) is assigned to several zones together. 4. Device according to claim 1 and 2, characterized in that a bypass (19) is assigned at least parallel to a volume flow regulating the process temperature, that a valve or a slide (20) is arranged in the bypass, and that this valve in the bypass (19) is coupled to the control valve for the volume flows, preferably in such a way that closing the volume flow valve is coupled to opening the bypass valve and vice versa. 5. Device according to claim 4,
characterized, that the tempering zones (2,3,4) are arranged parallel to each other and are flowed through by parallel volume flows of different strength and speed.