ELECTRIC BUILDING COMPONENT HEATING AND METHOD FOR APPLYING THE SAME

Description

[0001] The invention relates to an electric component heater comprising a cylindrical component, an electric heating element attached to the cylindrical component, and a tubular clamping sleeve made of a spring-elastic material adjacent to the electric heating element, the clamping sleeve having a cylindrical outer and inner surface, a continuous slot extending along its length, and a longitudinal axis, wherein the heating element is connected to the clamping sleeve at both axial ends, and the slot extends helically along the length of the clamping sleeve, wherein the clamping sleeve together with the electric heating element is clamped onto the component by exerting a radial clamping force.

[0002] Such component heaters are known, for which DE 103 56 059 B4 and EP 0 653 283 B1 are cited as examples. They serve to heat the cylindrical component, which may be, for example, an injection nozzle of injection molds or a corresponding hot runner for conveying a plastic melt, to its operating temperature. The component heaters must be easy to mount and dismount, require little space, and ensure a sufficiently high clamping force on the component even under high temperature cycling and operating temperatures up to approximately 500 °C. Furthermore, they should also compensate for existing tolerances in the component diameter and be adaptable to different requirements through different designs of the heating element.

[0003] From EP 2 848 381 A1, an electric component heater with the aforementioned features is known, wherein the clamping sleeve can be temporarily expanded by axial compression in order to mount or dismount it on a cylindrical component, and a reduction in diameter and generation of a clamping force can be achieved by axial stretching of the clamping sleeve.

[0004] DE 10 2009 039 778 A1 discloses a heating element with a slotted, highly thermally conductive sleeve that has a groove for receiving the heating element, which is wrapped with the heating element. The sleeve thus serves only to achieve a uniform and reproducible heat distribution, but not as a clamping sleeve for securing the heating element to the component. For disassembly, the known sleeve can be widened in the area of ​​the groove using a tool.

[0005] The object of the invention is to propose an electric component heater of the type mentioned above, which can be manufactured particularly easily and flexibly, is cost-effective to produce and can be assembled with reduced effort.

[0006] To solve the problem posed, the invention proposes the design of an electric component heater according to the features of claim 1.

[0007] Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0008] The inventive proposal provides that the component heater further comprises a rotary tool and the clamping sleeve has at least one end a recess designed for the engagement of a rotary tool, into which the rotary tool can be inserted in order to effect an elastic expansion or compression of the clear inner diameter of the clamping sleeve and the heating element by applying a torque directed about the longitudinal axis at one end and fixing the opposite end.

[0009] Due to the helically circumferential slot provided according to the invention along the length of the clamping sleeve, it is possible, for example, to position a turning tool in a recess provided for this purpose at one of its ends and to fix the opposite end, for example, by hand or also by means of a turning tool acting there. Subsequently, by applying a sufficiently high torque, which must be applied manually, an elastic expansion or compression of the clear inner diameter of the clamping sleeve can be effected along the helically circumferential slot. Since the heating element is connected to the clamping sleeve in the region of both axial ends of the same, the diameter of the heating element itself is also varied accordingly. Alternatively, the torque can also be applied manually.

[0010] If the component to be heated is a cylindrical component on whose outer surface the electric component heating according to the invention is to be applied, the electric heating element is applied to the cylindrical outer surface of the component and the clamping sleeve is arranged so that it surrounds the electric heating element on the outside in the manner of a jacket, i.e. the electric heating element lies on the inner jacket surface of the clamping sleeve.

[0011] Alternatively, the clamping sleeve can be applied directly to the component to be heated, and the electrical heating element is located in the area of ​​the outer surface of the clamping sleeve.

[0012] It is therefore possible to manufacture the electric heating element and / or the clamping sleeve slightly undersized with respect to the diameter of the component to be heated and, before mounting it on the component, to widen the clamping sleeve together with the heating element fixed to its end with respect to its respective diameter by means of the applied torque.

[0013] In this expanded state, the clamping sleeve, together with the electrical heating element located inside it, can be pushed axially onto the component to be heated. After the torque is subsequently released, the clamping sleeve and the heating element elastically return to their original shape, reducing the inner diameter, and the clamping sleeve, along with the electrical heating element, clamps securely onto the component as desired.

[0014] It is also possible to heat a component with a cylindrical receiving bore using the component heating system according to the invention. In this case, the heating element is inserted into the cylindrical receiving bore, and the clamping sleeve rests against the heating element on the inside, acting like a core. In this case, the clamping sleeve and the heating element are preferably manufactured slightly oversized with respect to the diameter of the receiving bore of the component to be heated and are compressed with respect to their respective diameters before assembly by means of the applied torque.

[0015] It is also possible to arrange the heating element in the area of ​​the inner surface of the clamping sleeve if the clamping sleeve is inserted into a cylindrical bore of a component in the manner of a core.

[0016] In this compressed state, the clamping sleeve, together with the electric heating element, can be inserted axially into the receiving bore of the component to be heated. After the subsequent release of the torque, the clamping sleeve and the heating element elastically return to their original shape, increasing their respective outer diameters, and the clamping sleeve, together with the electric heating element, clamps firmly onto the surface of the receiving bore of the component in the desired manner.

[0017] It is obvious that these types of fastening are particularly easy and quick to accomplish and, in reverse order, equally easy to remove.

[0018] According to one proposal of the invention, the slot runs in the form of a complete screw thread over the length of the clamping sleeve, which ensures a particularly uniform and easy change in the clear diameter in response to the applied torque.

[0019] Furthermore, it may be provided that the slot at the end regions of the clamping sleeve has a lower pitch than in the length section between the end regions, thereby achieving a uniform widening of the inner diameter of the heating element, even if the pitch differs.

[0020] According to a further proposal of the invention, one end region of the clamping sleeve is equipped with a recess for the passage of connecting sections of the electrical heating element, while the opposite end region has the recess for the engagement of the turning tool.

[0021] A standard hook wrench, such as those used for tightening and loosening fasteners like slotted nuts or covers, can serve as the turning tool. However, it is also possible to use other turning tools, and within the scope of the invention, alternative abutments for engaging a turning tool, such as a projecting cam or the like, can be provided instead of a recess.

[0022] The clamping sleeve can be made of a suitable spring-elastic material, for example stainless steel, wherein the spring force of the material used for elastic recovery is preferably maintained in a temperature range between room temperature and approximately 500 °C, and preferably with a constant spring force over the entire temperature range. Bimetallic sheets or clad sheets and other suitable materials can also be used. In particular, the clamping sleeve can also be made of brass or a brass alloy.

[0023] The production of the clamping sleeve is extremely simple, as a flat sheet metal blank of the material to be used can first be provided with the slot contour two-dimensionally and then formed into the desired cylindrical or tubular configuration, in which the slot then runs helically over the length of the clamping sleeve.

[0024] The electric heating element can be arranged in a helical shape in a manner known per se, wherein the slope of the helical path is constant or variable depending on the requirements.

[0025] Furthermore, the clamping sleeve can have at least one groove-shaped recess on its surface facing the heating element, i.e., the inner or outer surface, in which the electrical heating element is at least partially received. In the case of several such groove-shaped recesses, several electrical heating elements can be received to form several independent heating circuits.

[0026] The introduction of the groove-shaped recesses is particularly easy when manufacturing the clamping sleeve from a flat sheet metal blank, as they can be introduced two-dimensionally into the sheet metal blank before the sheet metal blank is formed into the tubular clamping sleeve.

[0027] According to a further aspect of the invention, an end region of the clamping sleeve can be designed such that the measuring tip of a sheathed thermocouple can be received directly or in combination with an additional component. In this case, the spirally extending slot along the length of the clamping sleeve can be designed so that the thermocouple can be guided through it to the other end of the clamping sleeve without increasing the installation space. The thermocouple can then be used, for example, to transmit feedback about the temperature applied to the component heater to a control device.

[0028] Due to the arrangement of the helical slot extending along the length of the clamping sleeve as provided in the invention, the torsional stiffness can be individually adapted to the winding pattern of the heating element by varying the screw winding height and can also be designed differently over the length of the component heating according to the invention.

[0029] The achievable clamping force of the clamping sleeve according to the invention can be variably adjusted by varying the material, the tempering and the material thickness.

[0030] By selecting and / or varying the gap widths or making further milling cutouts in the clamping sleeve, mounting space can be created for the protected guidance and fixing of a sheathed thermocouple.

[0031] The clamping sleeve can be made of various steel or non-ferrous metal alloys and exerts a radially acting clamping force on the heating element, which thereby comes into secure contact with the component to be heated, ensuring good heat transfer.

[0032] The clamping sleeve also allows the heating element to be firmly connected to the clamping sleeve at both ends, e.g. by soldering, welding or a positive-locking connection.

[0033] In addition to the mechanical functions described, the clamping sleeve can have heat-insulating and / or heat-distributing properties through appropriate selection of the material and design of the surfaces.

[0034] It is also possible to combine two or more concentrically arranged clamping sleeves made of different materials in order to combine the different material properties.

[0035] The application of such an electric component heater to a cylindrical component is based on the fact that the component heater comprises an electric heating element and a tubular clamping sleeve made of a spring-elastic material, which surrounds the heating element on the inside or outside and has a cylindrical outer and inner surface and a longitudinal axis as well as a continuous slot extending along its length, wherein the slot, viewed over the length of the clamping sleeve, runs helically and is formed with a recess at one end, and the heating element is connected to the clamping sleeve at both axial ends and comprises the following steps: a) Applying a rotary tool to the recess and applying a torque around the longitudinal axis of the clamping sleeve and fixing the opposite end, such that the clear diameter of the inner surface expands elastically; b) axially applying the expanded clamping sleeve and the electrical heating element to the cylindrical component; c) releasing the applied torque with elastic return of the clamping sleeve and generating a radial clamping force in the direction of the heating element and the cylindrical component.

[0036] Alternatively, the insertion of an electric component heater into a cylindrical receiving bore of a component can be carried out such that the component heater comprises an electric heating element and a tubular clamping sleeve made of a spring-elastic material, which surrounds the heating element on the inside or outside and has a cylindrical outer and inner surface and a longitudinal axis as well as a continuous slot running along its length, which runs helically over the length of the clamping sleeve and is formed with a recess at one end, and the heating element is connected to the clamping sleeve at both axial ends and comprises the steps a) Applying a rotary tool to the recess and applying a torque around the longitudinal axis of the collet and fixing the opposite end, such that the clear diameter of the inner surface is elastically reduced; b) Axially inserting the compressed collet and the electrical heating element into the cylindrical receiving bore of the component; c) Releasing the applied torque with elastic return of the collet and generating a radial clamping force in the direction of the heating element and the cylindrical receiving bore of the component

[0037] Further embodiments and details of the invention are explained below with reference to the drawing illustrating an exemplary embodiment. The drawing shows: Figure 1 shows a perspective view of an electric component heater according to the invention; Figure 2 shows the representation according to the invention. Figure 1with a semi-transparent clamping element; Figure 3 shows a schematic representation of the assembly of the component heating system according to Figure 1 Figure 4 shows a rotary tool according to Figure 3 Figure 5 shows a further embodiment of an electric component heater according to the invention.

[0038] The figures show an electric component heater 1 for a cylindrical component not shown, such as a hot runner nozzle of an injection molding machine for thermoplastic materials.

[0039] The electric component heater 1 comprises an electric heating element 2 with connection sections 20, 21 for connecting electrical supply lines (not shown), wherein the heating element 2 heats up when supplied with a corresponding electric current in the manner of a resistance heater.

[0040] As especially from the Figure 2As can be seen, the electrical heating element 2 is wound in a helical shape to adapt to the cylindrical component to be heated and is surrounded on the outside in the manner of a sheath by a cylindrical, tubular clamping sleeve 3 made of a spring-elastic material, for example a stainless steel sheet, whereby the end faces pointing in the direction of the longitudinal axis A remain open.

[0041] At the two axial ends lying in the direction of axis A, the heating element is connected to the inner surface of the clamping sleeve 3, for example by means of a spot weld or a soldered connection.

[0042] The clamping sleeve 3 has a continuous slot 31 extending along its length, which, viewed along the length of the clamping sleeve 3, i.e., in the direction of axis A, runs helically. Starting from a recess 35 that penetrates the cylindrical outer and inner surfaces of the clamping sleeve 3, such that the connecting sections 20, 21 extend through this recess 35, the continuous slot 31 initially runs with a shallow pitch for approximately 1.5 complete screw turns around the axis A of the clamping sleeve 3 in a first end region 33 of the clamping sleeve 3. Subsequently, the slot 31 extends with a significantly steeper pitch over a longitudinal section 36 of the clamping sleeve 3, viewed along the length of the clamping sleeve 3 in the form of a complete screw turn.In the area of ​​the opposite end region 34 of the clamping sleeve 3, which adjoins the length section 36, the gap 31 again runs in a manner comparable to the end region 33 with a correspondingly lower slope over approximately 1.5 complete screw turns around the axis A of the clamping sleeve 3 and ends in a recess 32.

[0043] The recesses 32, 35 and the continuous slot 31 penetrate the clamping sleeve 3 completely perpendicular to the axis A, i.e. they extend from the outer surface to the inner surface of the clamping sleeve 3.

[0044] Corresponding to the different slope profile of the slot 31, the helical arrangement of the electrical heating element 2 is also designed with different slopes, specifically with a shallower slope at the end regions 33, 34 than in the region corresponding to the length section 36. These different winding densities of the heating element 2 allow the power distribution to the component to be heated to be varied according to requirements.

[0045] In the assembled state of the component heater 1 (not shown here), the clamping sleeve 3 serves to clamp the electric heating element 2 onto the component. For this purpose, the electric heating element 2, together with the surrounding clamping sleeve 3, is slid onto the cylindrical component to be heated, which has a corresponding diameter. The component is then positioned along axis A in the area of ​​the clear diameter D of the component heater 1, see [reference]. Figure 3The spring-like properties of the clamping sleeve 3 and its appropriate diameter ensure that the clamping sleeve 3 exerts a radially inward clamping force on the windings of the electric heating element 2 and the component located inside, thus fixing the component heater 1 to the component and establishing good surface contact between the component and the windings of the electric heating element 2. At the same time, the clamping sleeve 3 ensures a uniform temperature distribution and protects the electric heating element 2 from external damage.

[0046] The material of the clamping sleeve 3 is selected so that the applied clamping force remains almost constant over the expected temperature range, which is usually up to 500 °C.

[0047] To mount the illustrated component heater 1 onto the cylindrical component, a standard hook wrench is used according to Figure 4used as a rotary tool 4, which has a handle 41 and a curved part adjoining the handle 41, which has an inwardly projecting hook 40 at its free end and a support surface 42 in the transition area to the handle 41.

[0048] As can be seen in particular from the Figure 3As can be seen, the rotary tool 4 for mounting the electrical component heater 1 is inserted into the recess 32 of the clamping sleeve 3 with the protruding hook 40 and is supported with its support surface 42 on the opposite circumferential section against the outer surface of the clamping sleeve 3 in the end region 34. The opposite end region 33 of the clamping sleeve is fixed, for example, by hand, and by applying a torque as indicated by arrow F via the attached rotary tool 4 about the axis A, the clear diameter D of the clamping sleeve 3 and of the heating element 2 fixed to its end widens due to the helical shape of the slot 31. In the end region 33, a corresponding counter-torque FG is generated by the fixed clamping, for example, by hand.

[0049] The clamping sleeve 3, thus widened in its clear diameter D, can then be pushed axially along the axis A onto the cylindrical component to be heated, together with the electrical heating element 2 arranged along the inner surface and also slightly elastically widened.

[0050] As soon as the torque F applied via the attached turning tool 4 is released, the clamping sleeve 3 elastically returns to its initial configuration and clamps the electrical heating element 2 in the desired manner by reducing the clear width of the diameter D on the component to be heated.

[0051] Such assembly can be accomplished very easily and quickly using standard rotary tools, and disassembly can be carried out just as easily and quickly in reverse.

[0052] The different slopes selected in the individual sections 33, 34, 36 of the continuous slot 31 allow the widening to be varied or kept constant for different slopes of the heating element.

[0053] Therefore, by adapting the course of the gap 31 of the clamping sleeve 3 to the component-dependent winding scheme of the electric heating device 2, the torsional stiffness of the clamping sleeve 3 can be adapted to the electric heating device 2 and uniform clamping can be enabled.

[0054] Furthermore, the overall clamping force achievable by the clamping sleeve 3 can be optimized by varying its wall thickness.

[0055] By varying the number of turns of the electric heating device 2, the power distribution to the component to be heated can be varied, whereby an axially parallel course to the axis A can also be provided in length sections of the electric heating device 2 in order to create (almost) unheated zones.

[0056] Furthermore, an end region of the clamping sleeve 3 can be designed such that the measuring tip of a sheathed thermocouple can be accommodated directly or in combination with an additional component. In this case, the spirally extending slot 31 can be designed along the length of the clamping sleeve 3 so that the thermocouple can be guided through it to the other end of the clamping sleeve 3 without increasing the installation space. With such an integrated thermocouple, the current temperatures can be fed back to a control and regulation device.

[0057] In the Figure 5Figure 1 shows another embodiment of such a component heater. The clamping sleeve 3 again comprises a continuous slot 31 extending helically along its length and is, for example, made from a flat sheet metal blank that has been formed into the tubular or cylindrical configuration in a suitable tool.

[0058] In contrast to the previously described embodiments, in this embodiment the electric heating element 2 is not arranged in the area of ​​the inner surface of the clamping sleeve 3, but rather runs in the area of ​​the outer surface of the clamping sleeve 3. For this purpose, in this embodiment a groove-shaped recess is also provided in the area of ​​the outer surface, into which the electric heating element 2 is completely inserted, with the exception of the connection sections 20, 21.

[0059] This component heating system also according to Figure 5The recess 32 can be widened by applying a rotary tool to it, in order to clamp the widened clamping sleeve 3, together with the externally extending electrical heating element 2, onto a cylindrical component. The cylindrical component is therefore heated from the electrical heating element 2 through the clamping sleeve 3 onto the cylindrical component.

[0060] Alternatively, the described embodiments of the component heating can also be designed in such a way that they can be elastically compressed in diameter by applying a suitable rotary tool, so that they can be inserted into a cylindrical bore, for example a cylindrical component in the sense of the invention described herein, in which the component heating clamps itself after the applied torque is removed.

Claims

1. Electrical component heater (1), comprising a cylindrical component, an electric heating element (2) attached to the cylindrical component, and a tubular clamping sleeve (3) made of a spring-elastic material assigned adjacent to the electric heating element (2), which has a cylindrical outer and inner casing surface and a continuous slot (31) extending over its length and a longitudinal axis (A), wherein the heating element (2) is connected to the clamping sleeve (3) at both its axial ends and the slot (31) extends helically over the length of the clamping sleeve (3), wherein the clamping sleeve (3) together with the electric heating element (2) is clamped to the component by exerting a radial contact force, characterized in that the component heater (1) further comprises a rotary tool and the clamping sleeve (3) has a recess (32) at least at one end into which the rotary tool can be inserted in order, by applying a torque (F) directed around the longitudinal axis (A) at one end and fixing the opposite end, to cause elastic expansion or compression of the clear internal diameter of the clamping sleeve (3) and the heating element (2).

2. Component heater (1) according to claim 1, characterized in that the component is cylindrical and the heating element (2) is applied to the component and the clamping sleeve (3) surrounds the electrical heating element (2) on the inside or outside.

3. Component heater (1) according to claim 1, characterized in that the component has a cylindrical mounting bore and the heating element (2) is inserted into the mounting bore and the clamping sleeve (3) is arranged on the inside or outside of the electric heating element (3).

4. Component heater (1) according to any one of claims 1 to 3, characterized in that the slot (31) extends in the form of a complete screw thread over the length of the clamping sleeve (3).

5. Component heater (1) according to any one of claims 1 to 4, characterized in that the slot (31) extends along the length of the clamping sleeve (3) with varying pitch.

6. Component heater (1) according to any one of claims 1 to 5, characterized in that the slot (30) at the end regions (33, 34) of the clamping sleeve (3) has a smaller pitch than in the longitudinal section (36) between the end regions (33, 34).

7. Component heater (1) according to any one of claims 1 to 6, characterized in that an end region (33) of the clamping sleeve (3) has a recess (35) for the passage of connecting sections (20, 21) of the electrical heating element (2) and a recess (32) for engaging the rotary tool (4) is formed at the opposite end region (34).

8. Component heater (1) according to any one of claims 1 to 7, characterized in that the recess (32) is configured for engagement by the rotary tool (4) configured as a hook wrench.

9. Component heater (1) according to any one of claims 1 to 8, characterized in that the clamping sleeve (3) is made of a spring-elastic material, whose spring force is maintained between ambient temperature and 500°C.

10. Component heater (1) according to any one of claims 1 to 9, characterized in that the electrical heating element (2) is arranged in a helical form around the cylindrical component.

11. Component heater (1) according to any one of claims 1 to 10, characterized in that the measuring tip of a casing thermocouple is arranged in an end region of the clamping sleeve (3).

12. Component heater (1) according to claim 11, characterized in that the slot (31) is formed over the length of the clamping sleeve (3) in such a way that the thermocouple is arranged fully inside the slot (31).

13. Component heater (1) according to any one of claims 1 to 12, characterized in that the wall thickness of the clamping sleeve (3) varies over its length.

14. Component heater (1) according to any one of claims 1 to 13, characterized in that the clamping sleeve (3) has at least one groove-shaped depression on its surface facing the electric heating element (2), in which depression the electric heating element (2) is at least partially accommodated.