DE202014005708U1 - Device for controlling the temperature of an extruder or a plasticizing cylinder - Google Patents

Abstract

Device for temperature control of an extruder (1) or a plasticizing cylinder, wherein the device comprises at least one temperature-controlling tube coil (8) which is bent in a meandering shape and is in direct or indirect contact with the extruder (1) or plasticizing cylinder, characterized in that the Meander (9) of the meander-shaped curved pipe coil (8) are formed overbend.

Description

The invention relates to a device for controlling the temperature of an extruder or a plasticizing, wherein the device comprises at least one tempering coil, which is bent meander-shaped, and is in direct or indirect contact with the extruder or the plasticizing.

So far, extruders or plasticizing cylinders are mainly heated electrically. In some cases, there are also concepts for directly gas-heated plants or even those that are operated with a heat transfer medium, such as a fluid. Particularly in the inlet and outlet regions of an extruder or a plasticizing cylinder, high shear forces or pressure increases lead to a release of heat. For extruders and plasticizing, z. B. of blown film systems, this can lead to significant temperature peaks. Depending on the type of plastic granules, these can lead to thermal damage to the granulate. Extruders or plasticizing cylinders (hereinafter collectively referred to as extruders) therefore often require, in addition to heating, additional local cooling at the endangered areas.

For the heating or cooling of extruders different techniques are known. The so-called heating tape, as electric heating is the most common way to heat extruder. The electric heating of extruders has the disadvantage of an energy-inefficient control. Because it must be avoided in particular an overshoot of the temperature during the heating process. To avoid such overshoot, z. B. a fluid cooling may be provided, wherein the electric heater is controlled against the temperature of the fluid as a constant.

Insofar is already z. As a liquid temperature known, which is particularly used when high cooling capacities are needed and it arrives at a uniform temperature at the cylinder. Both water and special thermal oils are used here. For temperature control by means of fluids helical channels are often milled for forced delivery of the tempering medium into the interior of the cylinder liner. By means of a fluid, the extruder can thus not only be heated at different points, but also be cooled. In a context is z. B. from the JP 61-36347 a constructed from two half-shells sleeve known, each half-shell has a meandering curved tube coil. The meanders of the coil run transversely to the flow direction of the granules.

Relevant to the temperature of the extruder, so for the local cooling and heating of the extruder is a substantially same heat flux density over the surface to be heated or to be cooled. Because only by a substantially same heat flux density can be ensured that the granules are not damaged or the plastic receives a uniform quality.

In order to achieve a heat flow density substantially the same over the surface, that is, the amount of heat flowing through a known surface of the extruder at a given temperature difference, it is proposed according to the invention that the meanders of the meandering curved tube coil are designed to be over-arched for fluid transport. By such an over-arched design of the meander of the meandering curved tube coil is achieved that a larger area is covered by the meandering curved coil.

Each meander has two legs, which are connected by a web, wherein the legs are aligned in the region of their transition to the web of the adjacent meander converging. From this it becomes clear that an over-arched meander is one that is compressed in the direction of the course of the meander.

This can also be achieved by arranging the individual meanders at different radial distances from the extruder or the plasticizing cylinder.

According to a further feature of the invention, it is provided that the legs of individual meanders are separated from each other by thermal insulation elements. Due to the thermal separation of individual meanders and consequently only a minimal heat exchange, it is achieved that different temperatures can be run over the length of the extruder.

This can also be achieved by arranging the individual meanders at different radial distances from the extruder or the plasticizing cylinder.

According to a further advantageous feature of the invention, it is provided that a plurality of meander-shaped curved tube coils run substantially parallel to one another. This means that, for example, in the case of two mutually parallel meandering curved tube coils in which a fluid is conducted for cooling or heating, a significantly higher heat flux density can be achieved than with a single meander, since the amount of heat introduced into the extruder can be substantially greater , Also will be a very homogeneous temperature field generated. For the operation of the meandering curved coils, that is, the flow rate of the tempering, for example, a thermal oil or water, there are several possibilities. Thus, for example, be provided to operate the meandering curved coil with a fluid in the cross-flow or in cross-counterflow relative to the flow direction of the granules in the extruder or plasticizing. In particular, it has also been found to be particularly advantageous that the coils can be optimally insulated from the environment.

A special feature of these tempering elements is that they can be ideally insulated against the environment.

In at least two meandering curved coils, which are substantially parallel to each other, is provided according to a further feature of the invention, that the at least one coil in the cross-DC and the at least one further coil is operated in cross-counterflow. The flow from two different directions ensures a homogeneous temperature field at a relatively high heat flux density over the entire surface occupied by the coil.

It has proven to be particularly advantageous if the device has at least one half-shell for receiving at least one meander-shaped curved tube coil with over-arched meanders. Here, two half shells form a cuff. Such sleeves can then be brought as individual components in contact with the plasticizing cylinder or the extruder, where they serve for the required cooling or heating of the extruder. The use of such heating or cooling sleeves has the great advantage that they can be mounted on demand and variably on the extruder or plasticizing cylinder. The sleeves are made of a good thermal conductivity material, eg. As aluminum. The previously mentioned thermal insulation elements can be incorporated into the sleeve, that is, they are part of the sleeve.

In particular, it has also proven to be advantageous that the coils can be ideally insulated from the environment.

With reference to the drawings, the invention will be explained in more detail below by way of example.

1 shows schematically the mass cylinder of an extruder, wherein over the length of the mass cylinder of the extruder several sleeves are arranged with meandering curved coils;

2 shows schematically the formation of an over-arched meander with insulating element;

3 shows the arrangement of two mutually parallel pipe coils, between which insulating elements are arranged.

According to 1 is the mass cylinder of the extruder with 1 denotes the flow direction of the granules with 2 , On the mass cylinder are several half-shell-shaped cuffs 4 , wherein the meandering curved pipe coils 8th run in the individual cuffs transversely to the flow direction of the granules. The meandering curved coils 8th in the individual semicircular cuffs are how this is the 2 remove, bend over. Such meandering curved coil includes several meanders 9 , being a meander 9 two thighs 10 that is in the area of the transition to the bridge 12 of the neighboring meander converge. This means that the meandering curved coil in the direction of the direction of the meander (arrow 15 ) is compressed.

Out 3 It can be seen that with two meandering curved pipe coils running essentially parallel to each other 8th between the individual coils, and especially in the area of the webs 12 and / or thighs 10 , thermal insulation elements 20 are provided.

LIST OF REFERENCE NUMBERS

1

Extruder or plasticizing cylinder

2

Flow direction of the granules

4

shell-shaped cuff

8th

coil

9

meander

10

Thighs of the meander

12

Footbridge of the meander

15

arrow

20

insulating

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 61-36347 [0004]

Claims (8)

Device for tempering an extruder ( 1 ) or a plasticizing cylinder, wherein the device at least one tempering tube coil ( 8th ), which is bent in a meandering shape, and in direct or indirect contact with the extruder ( 1 ) or plasticizing cylinder, characterized in that the meanders ( 9 ) of the meandering curved coil ( 8th ) are formed over arch. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to claim 1, characterized in that the meander ( 9 ) two legs ( 10 ), which by a bridge ( 12 ), wherein the legs ( 10 ) in the area of their transition to the pier ( 12 ) of the neighboring meander ( 9 ) are aligned to each other. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to claim 2, characterized in that the legs ( 10 ) of individual meanders ( 9 ) by thermal insulation elements ( 20 ) are separated from each other. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to one of the preceding claims, characterized in that a plurality of meandering curved pipe coils ( 8th ) are substantially parallel to each other. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to any one of the preceding claims, characterized in that the fluid in the at least one meandering curved coil ( 8th ) in the cross-direct current or cross-countercurrent with respect to the flow direction (arrow 2 ) of the granules in the extruder ( 1 ) or plasticizing cylinder is performed. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to one of the preceding claims, characterized in that after at least two meandering curved pipe coils ( 8th ), which run substantially parallel to each other, at least one coil ( 8th ) in the countercurrent flow and at least one further coil ( 8th ) is operated in cross-direct current. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to one of the preceding claims, characterized in that the device has at least one half-shell ( 4 ) for receiving at least one meandering curved coil ( 8th ) with over-arched meanders ( 9 ) and possibly insulating elements ( 20 ) having. Device for tempering an extruder ( 1 ) or a plasticizing cylinder according to claim 7, characterized in that two half shells ( 4 ) form a cuff.

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