EP1431460A1 - Roadpaver and heating unit - Google Patents

Abstract

The road finisher comprises a working component which is heated by a heating element (H). Heat is provided on the intermediate member which is located in the heating area between the heating element and the working component (101). The heating element is laminar, and a heating coil is provided which is a spiral heater around the laminar base. The heating element my be supplied with a three-phase current by a three-phase generator (115). The heating element has a length of about 0.9 to 1.2 m and a width of about 50 to 100 mm, and is designed for a power input between 500 and 1000 Watts, preferably 600 Watts.

Description

The invention relates to a road paver specified in the preamble of claim 1 Art and a heating element according to the preamble of claim 11.

In the case of a paver processing hot paving material, working components must be used be heated up until the paving material is no longer glued on inclines. The temperature of the paving material is around 170 ° C. It will mostly heated before the start of installation and continued to be heated during installation. The working components can be the screed plates in the screed Tamper strips, pressure strips or installation material containers. In practice it is Usually, at least one electric flat heating element on the heating area of the smoothing plate to be assembled by a three-phase generator of the paver with three-phase current is supplied. Also in the tamper bar or an optional one Press bar is inserted at least one electrical flat heating element. The known Flat heating element is e.g. from a drawn round tube that is pressed flat, so that flat top and bottom sides are created. There is a heating coil in the flat tube from a coil spring wound heating wire inserted in a serpentine shape and secured and positioned in an insulating manner by a ceramic powder filling. such Flat heating elements can only be manufactured with a width of just under 20 mm. Due to the design, effective heat transfer essentially only takes place in the central area of the already narrow support surface, while in the peripheral areas of the support surface is hardly heated. This results in an unfavorable heating pattern in the heating area the working component. There are also long heating times and uneven Heizbilder. Another disadvantage is that the heating rods with one integrated, slim connection housing are formed on one rod end, the stands vertically from the heating element and through the aggressive used in the paver Media is easily damaged. When replacing a flat heating element Always replace the connection housing together with the electrical connection cable. Due to the difficult heat transfer of the flat heating element, a relatively high electrical supply power required. Because usually in one As a number of such heating elements is installed in paver, this means an undesirable one high load on the three-phase generator.

The flat heating element is conventionally placed on the smoothing plate with the sticking up from the smoothing plate Clamping screws and an overlying metal profile clamped. The Tensioning screws must be arranged to the side of the heating element. A direct one The alley defined by the tensioning screws in the heating area is not heated possible.

In the road paver known from US 6 318 928 B are on the smoothing plate Screed several heating elements mounted on a heat-distributing plate. each The heating element is a rigid hollow metal rod with an internal resistance coil. The heating elements are the usual heating rods in this technology, each one heat the limited heating area with a relatively undefined heating pattern.

From DE 46 03 33 C an electric radiator is known which has an elastic insert made of asbestos, around which an insulated resistance wire is wound. The isolated Heating coil is surrounded by a jacket made of thin sheet metal, which is in a strong Metal shell is housed. In the manufacture of the heating element strong shell pressurized so that after releasing the pressure from the press the helix into the asbestos insert against the inner shell. ?????

The invention has for its object a paver of the type mentioned Specify type or a heating element with which an optimized heating of the respective heating area is possible with only moderate power consumption.

The task is with the features of claim 1 or claim 11 solved.

A flat heating element can even be made in terms of its width, length and contour adapt even better to the heating area, thereby ensuring effective heat transfer already practically over the entire width of the heating element. The heating effect the heating element can be uniform or variable over its length and width his. Variable means that in zones of the heating area in which more heat is required for a specific heating pattern than in other zones, by the heating element pro Unit area is also provided more heat. This can be done on the one hand the outline shape of the carrier material wrapped with the heating conductor while remaining the same Winding density and / or by varying the winding density of the heating conductor to reach. The flat heating element is, so to speak, for the respective application or the heating area and the heating pattern desired in the heating area, the carrier material essentially determines the shape and size of the heating element and the heating conductor adapts to the conditions on the carrier material. The Heating element is excellent for heating the screed of the screed Road paver suitable, with an optimal heating pattern already on the smoothing plate moderate power consumption can be achieved by the heating element, if necessary the intermediate element the heat is distributed over a greater width and / or length. The Flat heating element is also for tamper bars or pressure bars or to be heated Suitable for containers.

In order to temporarily or permanently increase the heating output depending on requirements and / or To be able to change the heating pattern, at least a second (or another further) heating conductors can be provided on the carrier material, which can be activated optionally leaves. This can also be useful for reasons of redundancy, e.g. in the event of failure another heating conductor.

The heating conductor should have a ribbon-shaped cross-section so that it is comfortable and tight can be wrapped around the carrier material. A bandwidth between 1.5 and 4 mm, preferably at about 2.0 mm, with a strip thickness between 0.1 and 0.4 mm, preferably at about 0.2 mm, has proven to be very useful. As material for the Heating conductors are ideal, for example, tungsten or a tungsten alloy.

The heating conductor should be wrapped around the substrate so that the turns remain spaced apart. The winding density can be over Length of the carrier material must be constant, so that the heating element approximately consistently provides the same heating output per unit area. In use cases, in where the heating area zones with increased heat demand for a certain heating pattern has, for example, because nearby heat-absorbing facilities or masses are arranged, the winding density can be variable, i.e. that increased in zones If heat is required, the heating output per unit area is greater than in other areas of the heating element. If necessary. is at least in a zone with increased heat requirements another optionally activatable heating conductor is provided.

To increase the efficiency when heating the heating area, the the side facing away from the heating area of the carrier material wrapped with the heating conductor an insulation layer may be provided. The insulation layer drives the heat, so to speak in the desired direction in the heating area. The insulation layer can be in the heating element integrated and / or attached to an outside of the heating element his.

In view of the rough working conditions in the paver, that should be with the Heating conductor wrapped carrier material enclosed between flat cover plates be sealed so that no aggressive media can penetrate. The lower cover plate can form a heat-distributing intermediate member. Alternatively can a heat-distributing intermediate member under the lower cover plate to be placed.

The cover plates in the edge area of the heating element become structurally simple with one another tightly connected. For example, the edge of one is cut larger Cover plate wrapped around the edge of the other cover plate, and optionally soldered or welded or sealed in some other way. As Steel or aluminum is suitable for the cover plates. The flat heating element can have a total thickness of only between 4.0 and 10.0 mm, expediently of only about 5 to 6 mm, with carrier material being essentially one uniform thickness between only 1.0 and 3.0 mm.

A flat heating element is also suitable for a smoothing plate of conventional size a length between 0.9 and 1.2 m, preferably of about 1.1 m, and a width from about 50 to 100 mm, preferably about 60 mm, the heating element for one Power consumption between 500 and 1000 watts, preferably only about 600 Watts.

The carrier material is at least one rectangular strip. However, it is quite conceivable to put several strips of the carrier material next to each other, and each Wrap strips with the or a heat conductor so that the ends of the heat conductor be led out on the same side of the heating element.

According to another important aspect, there are openings for fastening elements in the heating element provided with which the heating element in a conventional manner the smoothing plate is mounted. The breakthroughs in the construction of the flat Heating element are easily passed through the heating element. Thereby the fit of the heating element improves under the operational thermal and also vibration forces and is also the one defined by the clamping screws Alley heated in the heating area of the smoothing plate.

In terms of ease of maintenance and operational safety, it is appropriate to to provide the heating element with a junction box, expediently on the side facing away from the heating area. The junction box can have spacers or attached directly to the cover plate of the heating element. in the If necessary, a terminal block is provided around the ends of the heating conductor and connect a connection cable and the connection during maintenance or To be able to solve exchanges. The connecting cable can be routed through the side be inserted into the junction box so that cleaning agents or others aggressive liquids do not stop there, but drain off immediately. As Connection cable feedthrough can be a conventional, heat-resistant cable gland serve in the position of use of the heating element on the working component is essentially horizontal. The bushings for the heating conductor ends and / or the openings should be sealed with potting compound so that none aggressive media penetrate inside the heating element.

Fig. 1

eine schematische Seitenansicht eines Straßenfertigers,

Fig. 2

eine Perspektivansicht eines Glättblechs mit darauf montiertem Heizelement,

Fig. 3

einen Querschnitt des Heizelements,

Fig. 4

eine Perspektivansicht des Heizelements,

Fig. 5

eine Perspektivansicht eines Details des Innenaufbaus des Heizelements,

Fig. 6

einen Abschnitt des verwendeten Heizleiters in perspektivischer Darstellung,

Fig. 7

eine Draufsicht auf einen Teil einer abgeänderten Ausführungsform, und

Fig. 8

eine Perspektivansicht einer weiteren Ausführungsform.

Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

Fig. 1

a schematic side view of a paver,

Fig. 2

1 shows a perspective view of a smoothing plate with a heating element mounted thereon,

Fig. 3

a cross section of the heating element,

Fig. 4

a perspective view of the heating element,

Fig. 5

a perspective view of a detail of the internal structure of the heating element,

Fig. 6

a section of the heat conductor used in a perspective view,

Fig. 7

a plan view of a part of a modified embodiment, and

Fig. 8

a perspective view of another embodiment.

A paver F in Fig. 1 has a chassis 108 with front wheels 105 and rear wheels 106. A bunker 113 is arranged on the chassis at the front end, behind which there is a diesel engine with a three-phase generator as the primary drive source 114 115 is located. Between the bunker 113 and the rear end of the chassis extends a longitudinal conveyor device 109, with the installation goods as a template 111 is placed on the floor behind the paver. At the rear end of the chassis a transverse distribution device 110 is arranged, which makes the template 111 more uniform and spreads out sideways. A screed 103 is towed on the side rails 104, which rides on the template 111 and forms a ceiling layer 112. The screed 103 has underside smoothing plates 101, which with flat heating elements H be electrically heated. Furthermore, a tamper T is indicated, which oscillates with one driven tamper bar 102 processed the installation goods. The tamper bar 102 can also be equipped with a heating element, not shown. With special Embodiments of screeds 103 can also use pressure bars (not shown) be provided, which are also heated with heating elements. It is also possible to heat containers of the paver F not shown with such heating elements. The heating elements H are generated by the generator 115, for example with three-phase current provided.

The smoothing plate 101 shown in Fig. 2 is a steel plate on which a flat here Heating element H is mounted with tensioning screws 3. Push through the tensioning screws 3 Breakthroughs 4 of the heating element H. The heating element H is approximately rectangular Stripes formed, for example, with a length of around 1.1 m and one Width of about 60 mm. Under the heating element H can be a heat-distributing intermediate member 1, e.g. a metal profile can be provided. A lies on the heating element H. Metal profile 2 shown in dashed lines the smoothing plate 101 tensioned. A junction box 6 is mounted on the heating element H, into which a connecting cable 7 is inserted horizontally. Others are also dashed Components of the screed indicated at 5, which may be the smoothing plate 102 contact and may require that there be a higher heating output per unit area is used in the smoothing plate 101 than in other areas. The pontic 1 'could be significantly wider and / or longer than the heating element H.

The cross section of the flat heating element H in FIG. 3 is not to scale, but exaggerated for clarity. The total height of the heating element H is only between 5 and about 10 mm. To generate heat is at least a heating conductor L is spirally wound around a flat carrier material M. The Backing material M, for example the consistency of a cardboard plate and only one Has thickness of about 1.0 mm, has an outline shape that matches the desired heating area or the required heat or heating pattern of the working component to be heated can be adapted. Insulating layers can be above and below the carrier material 8 may be provided. Furthermore, it is useful above thermal insulation 9 to be provided in order to specifically drive the heat down to the heating area. This layer structure is formed by a lower cover plate 10 and an upper cover plate 11 covered, with an edge 12 of the lower cover plate 10 at the top the edges of the upper cover plate 11 are folded over and tightly attached to it. The connection box 6 is indicated by dashed lines, the one with spacer elements 13 directly can be mounted on the upper cover plate 11. Thermal insulation (not shown) could also be provided in the side areas. The lower cover plate 10 forms a heat-distributing intermediate member, so that, if necessary, on the separate Intermediate link 1 or 1 'can be omitted.

In the perspective view of the flat heating element H in Fig. 4 can be seen how the openings 4 at the positions of the clamping screws of the smoothing plate Push through heating element H. However, the flat heating element H could also be without any breakthrough. The junction box 6 with its spacers 13 expediently has a removable cover 6a and a horizontal one horizontal bushing 6b for the connecting cable 7. Inside the junction box 6, a terminal strip 14 indicated by dashed lines can be provided on the the heat conductor ends inserted into the connection box 6 and the connection cable 7 be connected to each other. After removing the cover 6a can be exchanged of the heating element H, the connection cable 7 can only be loosened and then in place and Place remain. If necessary. the heat conductor L is connected directly to the connecting cable 7. The junction box 6 then serves to define the heating conductor ends and that Connection cable, e.g. to keep tensile forces away from the heating conductor L

Fig. 5 shows that the heating conductor L in e.g. wrapped around the carrier material M. Windings 15 run between which there are intermediate distances 16. x means an area of higher turn density, while y an area of lower turn density shows. The openings 4 can, for example, through the carrier material run between the turns 15. In area X is the heating output per unit area larger than in the y range. The heating conductor L could alternatively be in the longitudinal direction of the carrier material M are wrapped around it. Alternatively, at least a further, preferably selectively activatable heating conductor in turns 15 ' the carrier material M may be wound, e.g. allows a second heating level.

6, the heating conductor L is expediently a profiled heating wire with a rectangular one or oval band cross-section and a band width b between 1.0 and 5.0 mm and a tape thickness h between 0.1 and 0.5 mm. The heating conductor L is with his Flat side placed on the backing material M and bent transversely to the band thickness h.

Fig. 7 indicates that the openings 4 alternatively by two side by side Strips of the carrier material M can be defined. Any streak or at least a strip has a cutout 17 on the edge as a surround of the opening 4. The respective heating conductor L is wrapped around the cut edge, so that the area around the opening 4 is also heated. The heating conductor ends are at 18 indicated.

As a rule, a strip (or two adjacent strips) of the carrier material M are sufficient to with the uniform or varying winding of the Heating conductor or with more than one heating conductor a predetermined heating pattern in the heating area to create. The heating power per unit area can be determined by the winding density be varied, or by the geometric outline shape of the carrier material M, and / or by means of at least one further heating conductor. The carrier material M can in an appropriate shape to meet the requirements of the heating sector to take account of its shape. A narrower area of the Carrier material M with then shorter turns of the heating conductor yields one lower heating output than a wider area of the carrier material with longer ones Turns. Since the heating conductor L is wrapped around the carrier material, it adapts Heat conductor to any desired outline contour of the support material M.

8 is a conventional heating element (with round or, as shown, flat squeezed cross section) stretched on the intermediate member 1, which on the Heating area of the smoothing plate 101 rests flat and the heat in width and / or Length distributed in the heating area. The intermediate link 1 is a metal profile (steel or Light metal) or with a heat transfer medium, e.g. Thermal oil, filled Hollow body. The heating rod is on the upper metal profile 2 and the clamping screws 3 stretched on the intermediate member 1 and the intermediate member 1 on the smoothing plate 101.

Claims (11)

Asphalt paver (F), with a screed (103) and at least one working component heated by means of at least one electrical heating element (H), for example a smoothing plate (101) of the screed (103), the heating element (H) being heat-transferring to a heating area of the working component and contains at least one heating coil, characterized in that the heating element (H) is flat, that the heating coil is at least one heating conductor (L) wound spirally around flat carrier material (M), and that the outline shape of the carrier material (M) and / or the winding density or the winding profile of the respective heating conductor (L) is adapted to a predetermined heating pattern in the heating area Paving machine according to claim 1, characterized in that the heating conductor (L) has a band-shaped cross section, preferably with a band width between 1.0 and 4.0 mm, and a band thickness between approximately 0.1 and 0.4 mm. Paving machine according to claim 1, characterized in that the heating conductor windings (15) are spaced apart and that the winding density is constant or variable over the length of the carrier material. Paving machine according to claim 1, characterized in that at least one further heating conductor (L), optionally connectable to a power supply, is wound in turns (15 ') on the carrier material (M). Paving machine according to claim 1, characterized in that at least on the side of the carrier material (M) wrapped with the heating conductor (L) facing away from the heating area, thermal insulation (9) is provided. Paving machine according to claim 1, characterized in that the carrier material (M) wrapped with the heating conductor (L) is enclosed between flat cover surfaces (10, 11), of which, preferably, the lower one forms a heat-distributing intermediate element, or on a heat-distributing intermediate element ( 1, 1 '), and that the cover surface (11, 10) in the edge region of the heating element (H) are tightly connected to one another, preferably by folding the edge (12) of a cover plate (10) around the edge of the other cover plate (11 ). Paving machine according to claim 1, characterized in that the flat heating element (H) has a total thickness between 4.0 and 10.0 mm, the carrier material (M) wrapped with the heating conductor (L) having a substantially uniform thickness between approximately 1. Has 0 and 3.0 mm. Road paver according to claim 1, characterized in that the flat heating element (H) for the smoothing plate (101) has a length of 0.9 to 1.2 m and a width of approximately 50 to 100 mm, and, preferably, for one Power consumption between 500 and 1000 watts, preferably around 600 watts. Paving machine according to claim 1, characterized in that openings (4) for fastening elements (3) of the working component are provided in the heating element (H), and that either the openings (4) the carrier material (M) between spaced turns (15, 15 ') of the heating conductor (L), or two strips of carrier material are arranged alongside one another on the longitudinal side, at least one of which has a cutout (17) on the edge to surround the opening (4), and that the heating conductor (L) is optionally locally wound around the cutout edge. Road paver according to claim 1, characterized in that a connection box (6) is fixed on the side of the flat heating element (H) facing away from the heating area, preferably via spacer elements (13) and directly on the cover plate (11), and that, preferably, in A sealed bushing (6b) for a connecting cable is provided on one side wall of the connection box (6) and is essentially horizontal on the working component when the heating element (H) is in use. Heating element (H) with at least one heating coil for electrically heating a working component of a paver (F), in particular a screed (101), a tamper bar or a pressure bar (102), characterized in that the heating element (H) is flat and the heating coil is on The first and at least one second, optionally power-supplyable heating conductor (L) is that the heating conductors are wound spirally in turns (15, 15 ') around a flat carrier material (M), and that the outline shape of the carrier material (M) and / or the winding density or the course of the turns of the heating conductors (L) are adapted to a predetermined heating pattern in the heating area.

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