DE1804777A1 - Heizglette with the same temperature status - Google Patents

Description

bag. 651

Heating godet with temperature compensation

B armag
Banner Maschinenfabrik Aktiengesellschaft

Wuppertal

The invention relates to a controllably heated, in particular electrically heated godet or roller for conveying and heating pad structures or strips, in particular made of synthetic material Material, preferably for those circumferential speeds at which the centrifugal force on the circumference is greater than the acceleration due to gravity "g" is, and at which godet or roller the heating device and a cavity partially filled with liquid are arranged inside.

Heated godets and rollers are already used in the textile industry used for many years. After the introduction of the synthetic Fibers are preferably used on textile machines in which such threads, e.g. made of polyamide or polyester, undergo heat treatment such as stretching or texturing. Especially when processing synthetic threads and film strips, however, there is often a requirement to maintain very precise processing temperatures and very narrow temperature ranges. However, there are still certain difficulties that exist

flatten or jacket temperatures over the total godet or keep the roller width even. It is often noted that

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if, for example, the middle section of the godet width has the desired temperature, but the edge zones below within the permissible temperature range. Even if it succeeds, by distributing the supplied heating power accordingly To achieve a uniform temperature profile in a certain operating state, this may change under certain circumstances completely when this operating state changes, e.g. at different speeds or with different material coverage. For example, a thread that runs cold on a heated godet and wraps around it several times can create the originally flat Completely distort the temperature profile, namely that the initially cold thread of the godet is close to the point of contact a lot, but withdraws less and less heat energy as the temperature increases. Make even small temperature differences at least noticeable in quality reductions, e.g. in the different colorability of the finished product to express. In order to meet the requirements of practice for a uniform surface temperature of the godets or rollers, A wide variety of heating systems have already been tried out, e.g. electrical resistance and inductive heating. One knows also already constructions in which a vaporous or liquid medium comes from outside via stuffing boxes or mechanical seals is fed to the rotating roller or godet. However, the design effort for this is high and the operational reliability is low.

In DBGM 1 964 3520 an electrically heated roller is described, which is designed as a hollow body partially filled with liquid. The liquid should be heated and then the Transfer heat evenly to the wall of the roller. That works oniert, however, only if there is a relative movement between the roller and. Liquid occurs, i.e. at speeds at which the centrifugal forces are not so great that a closed liquid

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keitsring forms on the circumference. In the latter case the liquid lies which is known to be a relatively poor conductor of heat, like an insulating ring on the inside of the roll shell. One can assume that the The layer that forms there is relatively thick or must be thick so that the radiators can be immersed in the liquid itself. Otherwise the efficiency is likely to be even lower. The task, namely the equalization of the roller temperature at Such high speeds, at which the centrifugal acceleration is significantly greater than the acceleration due to gravity, can be achieved with a. such facility cannot be satisfactorily resolved.

The invention is therefore based on the object of heating the godet or roller in such a way that even at high speeds at every point on the outer jacket surface, regardless of the amount discharged to the air or to the medium to be heated Amount of heat in each case so much heat is automatically supplied that the temperature in the jacket remains practically constant.

According to the invention it is therefore proposed that the godet or roller jacket is double-walled and the annular cavity between these walls, besides the liquid, only its vapors contains, is hermetically sealed and the inside of the outer jacket wall protrudes radially inward into the steam space projections and / or the outside of the inner jacket wall has radially outwardly projecting projections which are inserted into the through the Centrifugal force immerse the liquid layer lying on the inside of the outer shell wall in a ring shape. This training the Galette or roller enables or favors the process of certain physical processes described below, which result in the uniform temperature distribution on the godet or roller surface inevitably cause. You can therefore, from an automatic control of the heat flow at every point of the godet speak, whereby it should be noted that this regulation has nothing to do with regulating the level of the temperature as such.

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Taking into account the relevant characteristics described above, the device can be designed according to the various possible embodiments given in such a way that some or all of the projections extend essentially axially parallel or approximately axially parallel and one or more openings in the circumferential direction have and / or another part or all of the projections extend substantially in the circumferential direction and have openings have in the axial direction. As particularly advantageous from the point of view of manufacture and assembly of the godet or .Walze, an embodiment according to the invention has been found in which the projections of the inner and / or the outer shell wall have a helical course and possibly have interruptions.

Given the circumstances, according to which the greatest heat input from the heater in the middle and the greatest heat dissipation the jacket takes place at the end regions of the godet, it is further proposed that the outside of the inner jacket wall mainly in the middle area of the pallet width radially can have externally protruding projections and the inside of the outer jacket wall mainly in the edge areas of the godet or roll width may have radially inwardly projecting projections. *

In order to bring the necessary amount of heat to evaporate the liquid in the godet or roller, it is provided that the jacket walls of the godet or roller from a stationary resistance or induction heating device arranged in its interior or from a resistance heating device rotating with the godet or roller, which the electrical energy is supplied via slip rings, can be heated. It has become particularly important in structural terms The stationary induction heating device has proven its worth. In this context it is important for the efficiency of the godet advantageous »if according to the invention the jacket walls, in particular

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special the inner wholly or partly from one the warmth and material that conducts electricity well.

Some exemplary embodiments of the subject matter of the invention are shown schematically in the drawing. Show it:

Fig. 1 . the longitudinal section through the axis of rotation of a

Galette

FIG. 2 shows the section H-II through FIG. 1 without a heating device

Flg. 3-5 longitudinal sections through the axis of rotation of others

inventive godet designs

The godet according to Figures 1 and 2 consists essentially of the outer shell wall 1, the inner shell wall 2, the disc-shaped end wall J, which is in any usual, appropriately detachable catfish is connected to the drive shaft 4, and from the heating device 5. The jacket wall 1 has an axially parallel bore 6 which receives a temperature sensor can, which in a known manner with a commercial and therefore not shown device for regulation connected to the electrical energy required to feed the heating device. It also has the inside the outer shell wall 1 axially parallel ribs 7, which are comparable to internal teeth. In the gaps between the ribs 7 protrude ribs 8 on the outside of the inner Shell wall 2 sit and reach close to the bottom 9 of the gaps between the ribs 7 (Fig. 2). On the left and right At the end of the ribs 7 and 8, grooves 10 and 11 are provided as annular channels.

The heating device 5 can be a stationary electrical

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Be resistance or induction heating, which is attached to the machine frame by means of the federal government. If induction heating is used, the heating element 5 is designed as an electrical winding with an iron core, with only a small air gap remaining between the webs of the iron core and the inner jacket wall 2 in order to ensure a good transition of the magnetic lines of force into the jacket walls or to ensure over the inner jacket wall 2 in the outer jacket wall 1. An embodiment has proven to be particularly advantageous in which the middle section of the inner jacket wall in the area of the heating winding, i.e. between the webs of the coil-shaped core, is made of a metal, for example copper, which conducts heat and electricity well. This copper ring then acts like the short-circuited secondary coil with one turn in a transformer, in which a relatively strong current flows, which is converted into heat by the ear-fast resistance of the ring.

During the production of the godet, the jacket walls 1 and 2 are joined together in such a way that they are exactly coaxial with one another and that there are uniform spacings between the ribs 7 and 8 in the circumferential direction. The jacket walls 1 and 2 are so tightly connected at the end faces that the cavity created between them is hermetically sealed, except for one or two holes through which the liquid heating medium, for example water, is filled and the air is evacuated. Then these openings are also closed airtight. The amount of liquid filled in must be large enough to ensure that the heads of the ribs 8 are immersed in the layer of liquid which is formed at the base 9 of the gaps between the ribs 7 as a result of the centrifugal force during rapid rotation.

When the godet is heated up, the liquid 13 begins to evaporate. Due to the evaporation, the pressure and boiling point rise as the temperature rises, until the required and

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Operating temperature of the godet outer jacket set on the controller is reached. In a space filled and closed with a liquid and its vapor, there is a certain equilibrium between the amount of liquid and vapor or vapor pressure, which is determined by the temperature of the system. When heat is supplied to the water, steam is formed; upon withdrawal of Heat, i.e. cooling the steam, condenses it back into water.

In order to make use of these physical processes, the Galette be designed so that it favors the course of these processes. Since the heating of the godet from the inside, that is takes place on the inner shell wall 2, the heat must conductive projections 8 protrude so far outward that they are in the Immerse liquid 1} in order to convey the amount of heat necessary for evaporation through contact. The one from the outer Shell wall 1 inwards into the vapor space, between the liquid level and shell wall 2, protruding projections have the task of to condense the steam on their surfaces and the heat released from the inside to the outer jacket through the insulating layer To pass liquid layer through. In detail happens the following: At the outer godet jacket, heat is removed, both from the thread and from the surrounding air. Warmth flows from within over the ribs 7 to the outside, which naturally cool themselves as a result. Even the slightest decrease in temperature below the temperature leveled off in the liquid-vapor system on any surface, which is in contact with this steam has the consequence that steam condenses on such a surface. The one that becomes free, relatively Large heat of condensation is transferred to the jacket wall 1 via the ribs 7 passed on. The greater the heat gradient, the more violent the condensation, especially in the places where the greatest There is a heat demand. The pressure, which is reduced by the condensation, ensures that steam repeatedly flows in to this point. The centrifugal force hurls the freshly created contact on the ribs.

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densat immediately against the bottom of the gap 9 * so that there is no heat-insulating and the vapor-blocking liquid layer can collect at these locations. In addition, the centrifugal force ensures a Uniform distribution of the liquid, i.e. the surface of the liquid forms a cylinder concentric to the axis. the Liquid levels in the gaps between the ribs 7 can equalize in the circumferential direction via the grooves 10 and 11. As a result of the processes described above, there is a constant balance between discharged and supplied at each point Heat automatically in such a way that the temperature remains practically the same over the entire width of the godet jacket. Minor Deviations in the surface temperature can only be caused by the heat transfer resistance of the outer godet jacket the temperature drop in the jacket also increases at points of increased heat dissipation.

The dalette according to FIG. 2 differs from that according to FIGS. And 2 in the design and arrangement of the projections. The inner jacket wall 14 has projections 15 only in its central section, which are formed by screwing in self-contained grooves 16 in the circumferential direction and are interrupted by several axially parallel grooves, not shown in the section shown, evenly distributed over the circumference. The outer shell wall only has protrusions 18 in the end areas, which are formed by screwing in self-contained grooves 19 in the Urafangsrichtung and are also interrupted by several axially parallel grooves 20 evenly distributed around the circumference (only shown in the right end area). The projections 18 of the left end area sit in a ring 21 produced for itself, which is only inserted into the outer jacket wall 17 after the inner jacket wall Ik has been pushed into the outer jacket wall 17 and is firmly connected to it.

The projections 15 and 18 or the grooves 16 and 19 can also run helically. In this case, the separately prepared

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provided ring 21 can be omitted, and instead the screw-like Groove 19 can be worked directly into the correspondingly designed jacket wall 17. The shell wall is then used for assembly 14 very simply screwed axially into the outer jacket wall 17. The filling of the liquid, the evacuation and that The cavity between the jacket walls 14 and 17 is closed in the same way as described above.

The course of the physical processes in the liquid-vapor system is basically the same as in the godet version according to the Flg. 1 and 2. Since experience has shown that the heat dissipation is greatest in the area of the godet ends, only in these areas such projections l8 projecting from the inside of the outer jacket wall into the steam space are provided, on which the steam can preferentially condense. In the middle area, the condensation of the small vapor bubbles on the inner circumference of the is sufficient outer jacket wall, which is narrowed by the thin layer of liquid Gap penetrate between the outer circumference of the projections 15 and the inside of the outer jacket wall 17, namely at such points where the temperature of the outer wall is lower. The larger amounts of condensed liquid on the projections 18 in the end regions can through the axially parallel openings 20 back into the flow in the middle area, where they can evaporate again at the hotter projections 15.

In the embodiment according to FIG. 4, the outer jacket wall 17 can be designed exactly as that of the embodiment according to FIG. 5, ie it only has projections 18 in the region of the ends, specifically in the circumferential direction. The inner jacket wall 22 only has axially parallel projections 23 in the middle section. The same principle applies to the operation of the liquid-steam system of this godet as to the embodiment according to FIGS. 1 and 2. However, the course of the physical processes is advantageously supported by this design of the godet. Since the middle section of the casing walls naturally greets · Heat concentration prevails counter 1st of encryption

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steaming process and in the end areas of the godet the condensation process is most intense. Accordingly, pressure gradients form from the center to the ends, which the steam follows through the gaps between the ribs 25 to the projections 18.

Pig. 5 represents a simplified or cheaper design of the godet according to the invention in terms of production. It only has projections on one, preferably on the inner jacket wall 24, which, however, contrary to the solutions described so far, at least partially, in the example shown in FIG it is the projections 25 of the end regions, extend up to the opposite jacket wall 26 and lie firmly against this to achieve good heat transfer or are soldered to it. The projections 25, like the projections 18 in FIGS. 5 and k, have a plurality of aoh-parallel grooves distributed over the circumference to compensate for the liquid layer.

Of course, the godet designs according to Flg. 3 to 5 temperature measuring and regulating devices, which are not shown here.

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Claims (6)

- 11 - Bas. 651 claims 1. Controllably heated, in particular electrically heated godet or roller for conveying and heating thread structures or strips, especially made of synthetic material, preferably for peripheral speeds where the centrifugal force on the circumference is greater than the acceleration due to gravity "g ⁿ 1st" and which godet or roller the heating device and a partially liquid-filled cavity are arranged inside, characterized in that the godet or roller jacket is double-walled and the annular cavity between these walls only contains the vapors apart from the liquid, is hermetically sealed and the inside of the outer jacket wall has projections protruding radially inward into the vapor space and / or the outside of the inner jacket wall has radially outwardly protruding protrusions which dip into the liquid layer lying on the inside of the outer jacket wall due to the centrifugal force. 2. godet or roller according to claim 1, characterized in that some or all of the projections extend substantially axially parallel or approximately axially parallel and one or have several breakthroughs in the circumferential direction and / or a other part or all of the protrusions are essentially in Extend circumferential direction and have openings in the axial direction. 3. godet or roller according to claim 1, characterized in that that the projections of the inner and / or the outer jacket wall have a helical course and optionally have interruptions. - 12 - 009822/1806 - 12 - bag. 651 4. Galette or roller according to * Claims 1 to 3 * characterized in that « that the outside of the inner jacket wall is mainly radial in the middle area of the godet width has outwardly protruding projections and the inside of the outer jacket wall protruding radially inward mainly in the edge areas of the godet or roller width Has projections. 5. godet or roller according to claims 1 to 4, characterized in that that the jacket walls of the godet or roller of a stationary in their interior arranged resistance or Induction heating device or from an electrical resistance heater rotating with the godet or roller direction to which the electrical energy is fed via slip rings is, are heatable. 6. godet or roller according to claims 1 to 5, characterized in that that the jacket walls, especially the inner ones, in whole or in part, consist of heat and electricity consist of a highly conductive material. 009822/1 806 L e r s e i t e