DE102021109063A1 - Tension electric heater - Google Patents

Abstract

Electric heating device (100,200,300) with an axial opening for receiving an object to be heated, with an electric heating element (110,210,310) and with a clamping jacket (130,230,330) for generating an adjustable force acting radially in the direction of an axis (A) of the axial opening , wherein at least the clamping jacket (130,230,330) of the electrical heating device (100,200,300) has at least in sections a recess (131,231,331), the width (b) of which can be changed by means of at least one clamping slide (140,240,340), the clamping slide (140,240,340) overlapping the recess (131,231,331) , wherein the clamping slide (140,240,34) is arranged at least in sections between the clamping jacket (130,230,330) and an outer tube (160,260,360).

Description

The invention relates to an electrical heating device with the features of the preamble of claim 1.

Known from the prior art are heating devices with an electrical heating element, which are pushed onto a body to be heated and fastened there by clamping. For example, such heating devices are used in injection molding machines or in hot runner and distributor systems as nozzle heating for heating nozzle bodies.

It is already known from the prior art available on the market to provide a one-piece clamping jacket in direct contact with the heating element or, for example, if this is embedded between an inner and an outer metal jacket, in indirect contact around the heating element Has mutually overlapping portions viewed in direction, between which a wedge mechanism operated with a screw is arranged. If the screw is turned in one direction, the wedge mechanism is moved so that its height changes, which brings about an increase in the distance between the overlapping sections of the clamping jacket, which, because of the substantially constant length of the clamping jacket, leads to a clamping of the heating device on the heating body leads. Turning the screw in the other direction makes it possible to loosen the clamping sleeve again.

The problem with this heating device with clamping jacket is the increased space required by the clamping mechanism in the radial direction due to the wedge mechanism, because in many cases, especially with hot runner nozzles, the individual nozzles to be heated are arranged in blocks and there is only a relatively narrow one between the nozzle and the block , tubular channel available into which the heater must fit.

In particular for applications in which such an increased space requirement can not be satisfied, heating devices with clamping devices have been developed, such as those in FIG DE 10 2013 111 303 A1 or the DE 20 2011 003 451 U1 are disclosed. These heating devices have a slot penetrating them in the axial direction. Furthermore, clamping slides bridging the slot are provided, which interact with the outer jacket of the heating device in such a way that their displacement in the axial direction changes the width of the slot in the circumferential direction, thereby achieving clamping on the body to be heated. In practice, however, it has been shown that on the one hand these clamping slides can be lost and, on the other hand, cannot always apply the desired clamping forces.

The object of the invention is thus to provide a tensionable heating device in which the tensioning device is less easily lost. This object is achieved by a heating device with the features of claim 1. Advantageous further developments of the invention are the subject matter of the subclaims.

The electrical heating device according to the invention has an axial opening for receiving an object to be heated, the outer contour of which can typically be cylindrical at least in sections, an electrical heating element which preferably surrounds the axial opening at least in sections and a clamping jacket which is preferably in the form of a cylinder jacket or a truncated cone jacket for generating an adjustable, force acting radially in the direction of an axis of the axial opening.

• Die Geometrie einer solchen Heizvorrichtung kann insbesondere vorzugsweise unter Rückgriff auf Begriffe aus der Geometrie des Zylinders bzw. des verallgemeinerten Zylinders und Zylinderkoordinaten beschrieben werden. Die Richtung der Zylinderachse ist durch die Achse, die die axiale Öffnung der Heizvorrichtung, in welche der zu beheizende Gegenstand in der Regel eingeschoben wird, definiert, vorgegeben und wird nachfolgend als axiale Richtung bezeichnet.

The following explanations should contribute to an even clearer understanding of this terminology, which is in itself clear:

• The geometry of such a heating device can in particular preferably be described with recourse to terms from the geometry of the cylinder or the generalized cylinder and cylinder coordinates. The direction of the cylinder axis is predetermined by the axis that defines the axial opening of the heating device, into which the object to be heated is usually inserted, and is referred to below as the axial direction.

A force acts radially in the direction of this axis when it acts on a connecting line perpendicular to this axis between a point on the cylinder jacket and a point on the axis in the direction of the axis and is therefore particularly suitable for connecting the electrical heating device to a to press the object to be heated arranged in its axial opening.

The course of an electrical heating element in space can be described in particular in these cylindrical coordinates, i.e. by the position on the axis of the axial opening, the distance in the radial direction from the axis of the axial opening and a polar angle between 0 ° and 360 °. The electrical heating element surrounds the axial opening at least in sections when different polar angles for describing the course of the electrical heating element lie in the area of the axial opening. In particular, this is the case when the side of the axial opening facing electric heating element lies on an imaginary cylinder or truncated cone surface, which preferably coaxially encloses the axial opening, which in turn is particularly the case when the electric heating element runs in a spiral or meandering manner on an imaginary cylinder or truncated cone, the slope in the direction parallel to Cylinder or truncated cone axis can vary.

According to the invention, at least the clamping jacket of the electrical heating device is penetrated at least in sections by a recess, which can in particular be designed as a slot. A recess is therefore also to be understood in particular as an opening or perforation; Groups of openings or perforations are also conceivable. The recess penetrates the clamping jacket at least in sections and therefore does not necessarily have to extend over its entire length.

The width of the recess or in particular of the slot, which can be understood as the distance from one another essentially perpendicular to the axis of the axial opening opposite edge points of the recess, must be changeable by means of at least one clamping slide that overlaps the recess at least in sections.

An alternative description of the fact that the width of the recess can be changed by means of the clamping slide which at least partially overlaps the recess can again be made with recourse to a description of the recess in cylinder coordinates: Covered at every point on the cylinder axis at which there is a recess this has a certain polar angle range. If the polar angle range covered by the recess varies at different positions of the clamping slide at such points on the cylinder axis, the width of the recess can be changed by means of the clamping slide.

The recess, in particular if it is designed as a slot, preferably starts from one end of the electrical heating device; particularly preferably it runs continuously from one end to the other end, but this does not necessarily have to take place in a straight line.

It is essential to the invention that the clamping slide is arranged at least in sections between the clamping jacket and an outer tube. This leads directly to the fact that the cocking slide can no longer be lost because the outer tube captively holds the cocking slide in the guide that defines its movement; he can no longer fall out of the leadership.

Typically, this guide is defined by a recess, e.g. an opening, a recess or a groove, in the clamping sleeve or clamping slide, into which a projection engages, which is arranged on the clamping slide or clamping sleeve, the projection preferably being adapted to the width of the recess.

It should be noted in particular that the tensioning jacket in various embodiments of electrical heating devices according to the invention can be implemented on the one hand as a separate, additional component, for example an additional, separate jacket, but on the other hand also by different components of the electrical heating device itself. For example, in electrical heating devices in which the electrical heating element is embedded in a highly thermally conductive powder or granulate, the tensioning jacket can define the interior space between a tubular inner jacket with a recess, which can in particular be designed as a slot, and a tubular jacket with a recess, which is usually arranged concentrically therewith which can be designed in particular as a slot, which are connected to one another by lateral boundary surfaces at the edges of the recesses or slots, are formed by the tubular jacket with a recess, in particular a slot.

In embodiments in which a coiled electrical heating element in the form of a coiled tubing cartridge is surrounded by a tubular jacket with a recess, which can in particular be configured as a slot, on which it rests directly, this jacket can also form the clamping jacket. And in embodiments in which a coiled tubing cartridge is inserted into a groove made in a metal surface, the metal surface being a surface of a metal body preferably in the form of a tube, in particular slotted, but this shape can also be worked through, for example, from the solid A metal plate can be rolled up before or after the insertion of the coiled tubing cartridge, this metal body can form the clamping jacket; the clamping jacket can, however, also be formed by a slotted additional tube pushed onto the slotted tube defined in this way.

In all cases, however, there must be an additional outer tube that covers the cocking slide at least in sections and thus fixes it.

If the clamping jacket and / or the outer tube have a recess in which the clamping slide, at least in sections, in particular with its lower axis, the axis of the axial opening facing area in the case of a recess in the clamping jacket or with its upper area facing away from the axis of the axial opening in the case of a recess in the outer tube, it can be avoided that such an arrangement leads to higher space requirements than known electrical heating devices with clamping slide to have. This applies in particular in the event that the depression is so deep that the cocking slide can completely dip into it and its surface is flush with the surface surrounding the depression.

An embodiment of the invention is preferred in which the guides are implemented in such a way that the clamping slide has at least one radially inwardly protruding projection on each side of the recess, in particular the slot, and that each projection into one in the clamping casing relative to the axis of the axial opening obliquely or curved recess, in particular recess, groove or opening engages, so that an axial movement of the clamping slide leads to a change in the width of the recess, in particular of the slot, because then different sections of the recess are at different distances from the respectively closest edge of the recess, in particular of the slot are removed, while the distance between the inwardly protruding projections is constant. If this is the case, the cocking slide can be made of thinner material. Conversely, however, the depressions on the clamping slide and the projections on the clamping jacket can also be provided.

To establish and release the tension, it is advantageous if the clamping slide has at least one tool holder and / or if the clamping jacket has at least one tool holder outside the area in which the clamping slide is displaceable.

In particular, the tool holder in the clamping jacket can be formed very easily by locally widening the gap.

In particular, pliers whose jaws are modified so that they can be used in such tool holders can be well suited for the adjustment. This need for modification is preferably avoided in that the tool holders in the clamping slide and / or clamping jacket are designed to accommodate a jaw of a pair of pliers.

It is particularly advantageous if the interaction between the clamping slide and the clamping jacket is established via separate projections which are attached to the clamping slide or the clamping jacket. Separate means that the projections are not integrally formed, but rather those that were originally additional components, which are then subsequently attached to the clamping slide or clamping sleeve, e.g. by welding, soldering or gluing.

If the outer tube also has a recess, in particular a slot, the geometry of which is adapted to the geometry of the recess, in particular the slot of the clamping jacket and the outer tube is fixed to the clamping jacket, it can be avoided that, depending on the clamping state, the clamping jacket with its Recess, in particular the side opposite the slot, lifts off the outer tube during tensioning.

• 1a: eine Explosionsdarstellung eines ersten Ausführungsbeispiels einer elektrischen Heizvorrichtung,
• 1b: eine Gesamtansicht der elektrischen Heizvorrichtung aus 1a,
• 1c: eine Ansicht der Spannvorrichtung der elektrischen Heizvorrichtung aus 1b in entspanntem Zustand,
• 1d: einen Querschnitt durch die elektrische Heizvorrichtung aus 1b in entspanntem Zustand,
• 1e: eine Ansicht der Spannvorrichtung der elektrischen Heizvorrichtung aus 1b in gespanntem Zustand,
• 1f: einen Querschnitt durch die elektrische Heizvorrichtung aus 1b in gespanntem Zustand,
• 2a: eine Gesamtansicht eines zweiten Ausführungsbeispiels einer elektrischen Heizvorrichtung,
• 2b: eine teilweise geöffnete Ausschnittsvergrößerung aus 2a, die die Spannvorrichtung zeigt,
• Fig, 2c: einen Querschnitt durch die elektrische Heizvorrichtung aus 2a im Bereich der Verbindungselemente zwischen Außenrohr und Spannmantel,
• 2d: eine Ausschnittsvergrößerung aus 2c,
• 3a: eine Explosionsdarstellung eines ersten Ausführungsbeispiels einer elektrischen Heizvorrichtung, und 3b: eine Gesamtansicht der elektrischen Heizvorrichtung aus 3a.

The invention is explained in more detail below with reference to figures which represent exemplary embodiments. It shows:

• 1a : an exploded view of a first embodiment of an electrical heating device,
• 1b : an overall view of the electric heater from FIG 1a ,
• 1c : a view of the tensioning device of the electric heater from 1b in a relaxed state,
• 1d : a cross section through the electric heater 1b in a relaxed state,
• 1e : a view of the tensioning device of the electric heater from 1b in tensioned condition,
• 1f : a cross section through the electric heater 1b in tensioned condition,
• 2a : an overall view of a second embodiment of an electrical heating device,
• 2 B : a partially open enlarged section 2a showing the jig,
• 2c: a cross section through the electrical heating device 2a in the area of the connecting elements between the outer tube and the clamping jacket,
• 2d : an enlarged section 2c ,
• 3a : an exploded view of a first embodiment of an electrical heating device, and 3b : an overall view of the electric heater from FIG 3a .

1b Fig. 10 shows an overall view of an electric heater 100 and 1a one Exploded view of this electric heater 100 . The electric heater 100 has an essentially hollow cylindrical geometry, the cylinder axis of which is the axis A. forms its axial opening into which the object to be heated can be inserted and on which then by actuating a clamping device 150 , in the 1c respectively. 1e is shown enlarged in the relaxed or tensioned state, the electrical heating device 100 is fixed. The axial opening is created by an inner metal jacket rolled up to form a hollow cylinder, which here is the clamping jacket 130 forms, which has a groove into which an electrical heating element 110 , which can be a coiled tubing cartridge, for example, is inserted. Viewed in and of itself, this arrangement already represents a functional electrical heating device, that is to say it forms the actual electrical heating device in this embodiment.

The inner metal jacket or clamping jacket 130 is made of a recess designed here as a slot 131 interspersed lengthwise by a recess in the form of the receptacle 132 for a cocking slide 140 passes through, with the inclusion 132 a floor as a support surface on which the clamping slide 140 rests, has. The thickness of the cocking slide 140 and the depth of the shot 132 are coordinated in such a way that the cocking slide 140 with the outer surface in the radial direction of the inner metal jacket or clamping jacket 130 flees. The length of the recording 132 in the axial direction is greater than the length of the cocking slide 140 so that the cocking slide 140 in the recording 132 is displaceable in this direction.

The cocking slide 140 has one on different sides of the slot making the recess 131 forms a pair of projections arranged symmetrically to the slot 141 on, which is in the radial direction inward on the axis A. to extend. Like in the 1a shown are these protrusions 141 preferably formed by separate parts, which in corresponding openings 142 of the cocking slide 140 fitted and fixed there, welded here so that they are on the outside with the outer surface of the clamping slide 140 align and on the inside inwards over the inner, the axis A. facing surface of the clamping slide protrude.

In addition, the cocking slide 140 a tool holder in its central area 143 on.

For the variability of the width b of the slot that the recess 131 forms, is responsible that the clamping jacket 130 for the cocking slide 140 a pair of recesses arranged symmetrically to the slot on different sides of the slot 133 in the bottom of the intake 132 has, of which in the 1a until 1f but only one is visible at a time. The depressions 133 are designed as a breakthrough, so they penetrate the clamping jacket 130 each complete. They each run relative to the axis A. the axial opening at an angle so that the ends 133b each less far from the edge of the slot that forms the recess 131 forms are distant than the ends 133a .

The depressions 133 take the ledges 141 of the cocking slide 140 and, in cooperation with them, form a leadership. Because the distance between the respective pairs of protrusions 141 of the cocking slide 140 remains constant, there will be a change in the gap width b forced when moving the clamping slide in this guide, like the 1c and 1e illustrate.

You can also see the tension jacket 130 two tool holders each 134 , 135 that as a local extension of the slot that made the recess 131 forms are executed.

Based on the comparison of the cross-sectional representations of the 1d and 1f it can be seen that the tensioning of the tensioning device in this embodiment of the invention leads to the fact that when tensioning the heating device, as in the illustration of the tensioned heating device 100 in 1f is particularly well visible, a gap 139 between the cocking slide 140 and the tension jacket 130 arises, the one at the slot that the recess 131 forms, opposite side of the clamping jacket is largest.

The electric heater 100 also has an outer jacket 160 , which is pushed onto the actual electrical heating device and a passage opening 161 having access to the tool holders 134 , 135 , 143 allows, but has a smaller width than the cocking slide 140 , ie extends over a smaller polar angle range, so that the clamping slide in sections between the clamping jacket 130 , here more precisely the bottom of the recording 132 , and the outer jacket 160 is arranged and is thus arranged captive on the electrical heating device, while the actuation of the clamping slide 140 , in particular the introduction of a clamping tool into the tool holder 143 of the cocking slide 140 and tensioning or releasing the electric heater 100 with this tool is possible across its entire functional area.

The cocking slide form accordingly 140 and the tension jacket 160 the jig 150 . Will the cocking slide 140 moved in the direction in which the distance between the wells 133 the gap width is increased b reduced and thereby the electrical heating device 100 tense; a shift in the cocking slide 140 in the opposite direction leads to an enlargement of the gap b and relaxation of the electric heater 100 .

The ones in the 2a until 2d illustrated electric heater 200 with electric heating element 210 , Tension jacket 230 with a recess designed here as a slot 231 , Recording 232 , Recesses 233 and tool holders 234 , 235 , Cocking slide 240 with protrusions 241 , Openings 242 and tool holder 243 as well as outer jacket 260 with access opening 261 , is largely identical to the electric heater 100 according to the 1a until 1f constructed so that reference can be made to the description thereof, the reference symbols being obtained by adding 100 from the reference symbols used there. The difference between these two embodiments is that the outer jacket 260 the electric heater 200 also a recess designed as a continuous slot 262 has and is at least selectively attached to the clamping jacket, which is particularly good in the representation of the 2c and the associated enlargement of the 2d can be seen. This attachment is realized in that in the clamping jacket 230 Bores 238 are arranged in which sections 263 of the outer jacket 260 that would otherwise cover the respective bore 238 are bent in. As a consequence of this measure, the tensioning of the tensioning jacket also has a direct effect on the outer jacket, which leads to the formation of a gap like the gap 139 in the case of the electric heater 100 is avoided.

The ones in the 3a and 3b illustrated electric heater 300 with electric heating element 310 , Tension jacket 330 with a recess designed here as a slot 331 , Recording 332 , Recesses 333 and tool holders 334 , 335 , Cocking slide 340 with protrusions 341 , Openings 342 and tool holder 343 as well as outer jacket 360 with access opening 361 , is largely identical to the electric heater 100 according to the 1a until 1f constructed so that reference can be made to the description thereof, the reference symbols being obtained by adding 200 from the reference symbols used there. The difference between these two embodiments is that the clamping jacket 330 an additional receiving groove 337 for a thermocouple 370 has that the shape of the recess formed by the slot 331 deviates from the shape of a continuous straight line and that the cocking slide 340 in the side area of the electric heater 300 is arranged.

List of reference symbols

100,200,300

electric heater

110,210,310

electric heating element

130,230,330

Tension jacket

131,231,331

Recess

132,232,332

recording

133,233,333

deepening

133a, 133b, 333a, 333b

end

134,135,234,235,334,335

Tool holder

140,240,340

Cocking slide

141,241,341

head Start

142,242,342

opening

143,243,343

Tool holder

139

gap

150,250,350

Jig

160,260,260

Outer jacket

161,261,361

Access opening

262

Recess

263

section

337

Receiving groove

370

Thermocouple

A.

axis

b

broad

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102013111303 A1 [0005]
• DE 202011003451 U1 [0005]

Claims (9)

Electric heating device (100,200,300) with an axial opening for receiving an object to be heated, with an electric heating element (110,210,310) and with a clamping jacket (130,230,330) for generating an adjustable force acting radially in the direction of an axis (A) of the axial opening , wherein at least the clamping jacket (130,230,330) of the electrical heating device (100,200,300) has at least in sections a recess (131,231,331), the width (b) of which can be changed by means of at least one clamping slide (140,240,340), the clamping slide (140,240,340) overlapping the recess (131,231,331) , characterized in that the clamping slide (140,240,34) is arranged at least in sections between the clamping jacket (130,230,330) and an outer tube (160,260,360). Electric heater (100,200,300) according to Claim 1 , characterized in that the clamping jacket (130,230,330) and / or the outer tube (160,260,360) have a recess in which the clamping slide (130,230,330) is arranged at least in sections. Electric heater (100,200,300) according to Claim 1 or 2 , characterized in that the clamping slide (140,240,340) on each side of the recess (131,231,331) has at least one radially inwardly projecting projection (141,241,341) and that each projection (141,241,341) in a clamping jacket (130,230,330) relative to the axis (A) of the axial opening inclined or curved recess (133,233,333) engages, so that an axial movement of the clamping slide (140,240,340) leads to a change in the width (b) of the recess (131,231,331). Electric heating device (100,200,300) according to one of the Claims 1 until 3 , characterized in that the clamping slide (140,240,340) has at least one tool holder (143,243,343). Electric heating device (100,200,300) according to one of the Claims 1 until 4th , characterized in that the clamping jacket (130,230,330) has at least one tool holder (134,135,234,235,334,335) outside the area in which the clamping slide (140,240,340) is displaceable. Electric heater (100,200,300) according to Claim 5 , characterized in that the tool holder (134,135,234,235,334,335) in the clamping jacket (130,230,330) is formed by a local widening of the gap (131,231,331). Electric heating device (100,200,300) according to one of the Claims 4 until 6th , characterized in that the tool holder (134,135,143,234,235,243,334,335,343) is designed to accommodate the jaw of a pair of pliers. Electric heating device (100,200,300) according to one of the Claims 1 until 7th , characterized in that the interaction between the clamping slide (140,240,340) and clamping jacket (130,230,330) is produced via separate projections (141,241,341) which are attached to the clamping slide (140,240,340) or to the clamping jacket (130,230,330). Electric heating device (100,200,300) according to one of the Claims 1 until 8th , characterized in that the outer tube (160,260,360) also has a recess (261), the geometry of which is adapted to the geometry of the recess (131,231,331) of the clamping jacket (130,230,330) and that the outer tube (160,260,360) is fixed to the clamping jacket (130,230,330) .

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