DE102021106157A1 - induction formwork - Google Patents

Abstract

The invention relates to an induction formwork element which can be inductively heated for the production of a concrete part, comprising at least one carrier element which carries the other elements of the formwork element and absorbs and supports the mechanical load which acts on the formwork element and at least one formlining which has a matrix and at least one Induction layer includes, the induction layer consists of a ferromagnetic material and the induction layer and the matrix are firmly connected. The invention further relates to a heating system with an induction formwork element and a method for heating using a heating system with an induction formwork element.

Description

The invention relates to an induction formwork element which can be inductively heated for the production of a concrete part, comprising at least one carrier element which carries the other elements of the formwork element and absorbs and supports the mechanical load which acts on the formwork element and at least one formlining which has a matrix and at least one Induction layer includes, the induction layer consists of a ferromagnetic material and the induction layer and the matrix are firmly connected. The invention further relates to a heating system with an induction formwork element and a method for heating using a heating system with an induction formwork element.

The invention relates to the field of construction. When erecting or remodeling buildings, building parts are often formed by pouring concrete. The shape of these cast building parts is specified by a formwork, the formwork being erected on the construction site before the casting. In particular, ceilings or walls of a building are erected with the help of circuits. Heatable molds exist to accelerate the hardening of the concrete or to make it possible in the first place when the ambient temperatures are very low. Energy is supplied to these heatable formwork, which is transferred from the formwork to the cast concrete part. The transmitted energy heats the concrete part and thus accelerates its hardening.

Applicant's European patent specification EP 3 259 418 B1 discloses a formwork with an attachment, the attachment containing a heating device. The attachment with the heating device is reversibly connected to the actual formwork, so that the heating device can only be connected to the formwork when required, particularly at low ambient temperatures. If the heating device is not required, for example in the case of higher ambient temperatures, the attachment can be easily separated from the formwork. Such formwork can thus be flexibly adapted to the prevailing ambient temperatures. However, it has been found that large amounts of energy are required to operate such heatable formwork, since the heat transfer from the heating device in the attachment to the concrete part to be heated is not optimal. In this known heatable formwork, the actual heating device is relatively far away from the concrete part to be heated. During operation of the heating device, therefore, a relatively large proportion of the heat generated does not reach the concrete part, but heats other elements of the formwork or is lost to the environment.

The object of the invention is therefore to propose solutions with which formwork can be heated in a simple manner and with improved energy efficiency.

This object of the invention is achieved by an induction formwork element which can be inductively heated to produce a concrete part, comprising at least one carrier element which carries the other elements of the formwork element and absorbs and supports the mechanical load which acts on the formwork element, at least one formwork skin which has a Matrix and at least one induction layer, wherein the induction layer consists of a ferromagnetic material and the induction layer and the matrix are firmly connected to one another, the induction layer being flat and extending over at least 10% of the surface of the formwork skin in a top view of the formwork skin, wherein the formwork skin can be connected to and detached from the support element, the formwork skin having a support side which, when connected to the support element, faces towards the latter and the formwork skin having a workpiece side which is opposite the support side The lying side of the formlining is arranged and the workpiece side comes into contact with the concrete part to be created in the application. An induction formwork element according to the invention can be heated via the physical principle of induction, whereby the induction formwork element is suitable for heating the formed concrete part or building part at low ambient temperatures and thereby enabling or accelerating its hardening. With induction, an electromagnetic, time-varying alternating field is made available, which acts on the induction formwork element and which generates eddy currents inside the induction formwork element, which heat the induction formwork element from the inside through current heating. This principle of induction heating is known, for example, from induction cookers in the kitchen, where alternating electromagnetic fields cause the bottom of the cookware to heat up.

The induction formwork element according to the invention comprises a support element which provides the supporting structure for the further or the other elements of the induction formwork element. The carrier element absorbs the mechanical load which acts on the induction formwork element from the cast concrete part or parts of the building. The carrier element supports the other elements, such as the formlining. The carrier element can for example a frame composed of steel tubes. The carrier element preferably has a standard size with regard to the surface facing the concrete part. At the same time, the support element can have standardized interfaces for connection to other support elements in order to make it easy to assemble a complete formwork from a plurality of formwork elements. The induction formwork element according to the invention comprises at least one formwork skin which can be connected to the carrier element. Since the formwork skin wears out when it is used several times to produce a concrete part, the formwork skin is designed to be detachable from the carrier element in order to facilitate easy replacement of the formwork skin. The formwork skin can be connected to the carrier element, for example, by a nail connection, a rivet connection, a screw connection, a clip connection or by similar connection mechanisms. The formwork skin has two opposite sides in the direction of thickness: the workpiece side facing the concrete part to be produced and the carrier side facing the carrier element. In the case of application, i.e. when using the induction formwork element to erect a part of a building, the concrete touches directly the workpiece side of the formwork skin. The workpiece side facing the concrete part preferably has a water-repellent coating and is smooth, so that after the concrete part has hardened, the formwork skin can be easily separated from the concrete part again. There are no special surface requirements for the carrier side. The carrier side provides the surface with which the formlining touches the carrier element. It is also possible that both surfaces of the formwork skin can be used both as a workpiece side and as a support side, whereby the formwork skin is suitable on both sides to come into contact with the concrete part to be erected. Such a formwork skin can thus be turned over if one side is subjected to inadmissible wear, as a result of which the service life of the formwork skin can be extended. The formlining comprises several elements or components. One of these elements is the matrix, which preferably occupies the largest proportion of the volume of the formlining. The matrix ensures that the elements of the formlining are held together. The matrix is preferably formed from a non-metallic material. The matrix can consist of plastic, for example. Alternatively, the matrix can also be formed by one or more wooden panels or consist of materials which at least partially consist of renewable raw materials such as wood. The matrix can also include binders such as adhesives. The induction formwork element according to the invention also includes at least one induction layer made of a ferromagnetic material. The induction layer is the place in the induction formwork element in which, in the presence of an alternating electromagnetic field, eddy currents arise which heat up the formwork skin of the induction formwork element. In order for effective eddy currents to arise, the induction layer must have a certain minimum size. In a plan view of the formwork skin, for example from the workpiece side, the induction layer is designed such that it extends over at least 10% of the surface of the formwork skin. For this purpose, the induction layer can be self-contained and form a closed surface that occupies at least 10% of the surface of the formlining. Alternatively, however, several induction layers can also be provided distributed over the surface of the formwork skin, which together take up at least 10% of the surface area of the formwork skin. For optimal heating of the formwork skin, one or more induction layers are preferably provided, which together extend over a larger area of the formwork skin, for example over 30% or 50% of the surface of the formwork skin, viewed in a plan view. The induction layer can be arranged adjacent to the matrix in the thickness direction. In this case, the matrix and the induction layer form different but directly adjacent layers. In an alternative embodiment, the induction layer can be at least partially embedded in the matrix. This means that in this embodiment the matrix encloses at least part of the induction layer. In this embodiment it is also possible for several induction layers to be arranged within the matrix and for the matrix and the induction layers to form a common mixed layer. The formwork skin can have further elements or components which are described in embodiments of the invention.

An induction formwork element according to the invention significantly improves the energy efficiency when heating a formed concrete component compared to the prior art. In the case of the induction formwork element according to the invention, the currents which generate heat for heating the concrete part flow in the formwork skin itself and thus in the immediate vicinity of the concrete part to be heated. Heat transfer between a heating device arranged outside the formwork skin and the formwork skin is therefore not necessary. Since every heat transfer is subject to losses, the energy losses in the induction formwork element according to the invention are reduced compared to the prior art. In addition, the induction formwork element has a very simple and robust design and does not have any sensitive functional structures such as heating wires, cabling or control technology inside or directly adjacent to the formwork skin. The formwork of the induction element according to the invention can thus in the usual way, for example by Nail connections are connected to the carrier element without having to take sensitive components into account that could be damaged during the creation of the connection. In addition, the formwork skin of the induction formwork element according to the invention can be provided inexpensively due to its simple structure, which means that the formwork skin can be replaced, for example after excessive wear, without any particular expense. In addition, it is possible, as already described above, to turn the formwork facing while maintaining the functionality of the induction layer arranged on the inside. The induction formwork element according to the invention can be heated in a simple manner. An electromagnetic alternating field is provided for heating, which can, however, be introduced from outside, in particular through the matrix. A corresponding heating system is described further below. Due to the mode of action based on the principle of induction, no mechanical or electrical connection is required to supply the energy for heating the induction formwork element according to the invention. As a result, the initiation of the heating can be carried out particularly easily and quickly. Since no connections or the like are required on the formwork skin or on the induction formwork element, the induction formwork element can also be used without additional effort or hindrances in ambient conditions where heating of the formwork skin is not necessary and can therefore be omitted. The induction formwork element according to the invention behaves geometrically identically to a non-heatable formwork element and can therefore be installed and removed in a simple manner without special training for the working personnel.

In one embodiment it is provided that the induction layer is arranged within the matrix. In this embodiment, an induction layer or several induction layers are arranged inside the matrix. The matrix encloses the induction layer. In this case, a surface of the induction layer can form an outer surface of the formwork skin, which is arranged in particular on the carrier side. Arranging the induction layer within the matrix ensures a particularly strong bond between the matrix and the induction layer. In a case in which the matrix consists of a plastic, the induction layer can be encapsulated or overmoulded by the matrix during production of the formwork skin. This embodiment has the advantage that a non-corrosion-resistant induction layer, for example made of simple sheet iron, is protected by the matrix against environmental influences. Such an induction layer arranged inside the matrix is also particularly favorable for a formwork skin which can be connected to the support element in two directions. After turning the formwork skin over, the formwork skin still has essentially the same thermal properties as before turning.

In an alternative embodiment it is provided that the induction layer is arranged on the carrier side or the workpiece side. In this embodiment, the induction layer is either only partially enclosed by the matrix or represents a layer of the formwork skin that differs from the matrix. This embodiment has the advantage that the induction layer, which is heated by an alternating electromagnetic field, can be arranged even closer to the concrete part to be purchased . This is achieved when the induction layer is arranged on the workpiece side of the formwork. Alternatively, the induction layer can also be arranged as an independent layer on the carrier side of the formlining. In this case, an induction heater, which generates the electromagnetic alternating field required to heat the formwork skin, can be positioned directly adjacent to or in the immediate vicinity of the induction layer from behind on the formwork skin. This ensures that the field generated by the heater is optimally introduced into the induction layer. In this embodiment, the induction layer and matrix can be connected to one another, for example, by means of an adhesive connection. Alternatively, other connection mechanisms are also possible, such as screwing or nailing the two elements together.

Furthermore, it is provided that the induction layer is designed to be continuous or self-contained in a plan view of the formwork skin. In this embodiment, the induction layer is designed as a self-contained surface. The induction layer can be formed, for example, by a continuous iron sheet, which is arranged inside or adjacent to the matrix. This embodiment has the advantage that a large ferromagnetic surface is made available in which eddy currents can flow and heat the induction layer. In addition, a heater can be placed at various locations within the continuous area of the induction layer, viewed in a plan view of the formlining. It is always ensured that the electromagnetic field generated by the induction heater acts directly on the induction layer, i.e. from a very small distance. It is also possible to provide several self-contained induction layers which are arranged next to one another and/or one behind the other in a plan view of the formwork skin.

Alternatively, it is provided that the induction layer has recesses in a plan view of the formwork skin and is in particular designed in the form of a grid. In this alternative embodiment, the induction layer is not designed to be continuous, but has gaps when viewed from above. In this way, less ferromagnetic material is required to provide an induction layer. This reduces the weight of the formlining. For this purpose, the induction layer can be designed, for example, in the form of a grid and have recesses at regular intervals. Eddy currents generated by an electromagnetic alternating field can flow through the lattice structure in a manner similar to that through a continuous induction layer, as a result of which good current heating is also ensured in this alternative embodiment. As an alternative to a lattice structure, an induction layer that is interrupted in itself can also be formed by a plurality of irregularly shaped objects which at least partially touch one another. Such irregularly shaped objects can be formed, for example, by longer metal chips or the like, which are poured into a matrix.

Furthermore, it is provided that the induction layer is thinner than the total thickness of the matrix. In this embodiment, the thickness of the induction layer is less than the thickness of the matrix. Thickness is to be understood as meaning the dimension which is oriented in a direction from the workpiece side to the carrier side. The thickness of the induction layer is preferably significantly less than the thickness of the matrix and is, for example, 50%, 40%, 30%, 10% or 5% of the thickness of the matrix. A thin induction layer has the advantage that eddy currents generated in it, with a smaller thickness and thus a smaller cross-sectional area of the induction layer, generate greater current heating due to the higher ohmic resistance than with thick induction layers.

In an advantageous embodiment, it is provided that several induction layers are provided, which are arranged next to one another or at least overlapping in some areas in a plan view of the formwork skin. In this embodiment, the induction formwork element has a plurality of induction layers which, in a plan view of the formwork facing, can be arranged next to one another or one behind the other, at least in certain areas. The several induction layers can be connected to one another in an electrically conductive and/or thermally conductive manner. However, it is also possible to arrange several induction layers which are electrically and/or thermally insulated from one another. In this case it is possible to inductively heat only part of the formwork skin, while another part of the formwork skin is not heated.

Cleverly, it is provided that the formwork skin has a coating which is arranged on the side facing away from the carrier element adjoining the matrix and/or the induction layer, with the coating forming the workpiece side. In this embodiment, the workpiece side of the formwork skin is coated. A coating is provided in order to prevent or at least reduce adhesion of the concrete material to the formlining. The coating comes into contact with the concrete material during the erection of a building part or concrete part. The coating can also be referred to as a wear layer. The coating is preferably not intended to absorb mechanical loads. The mechanical loads, which act on the formwork from the concrete part to be erected, are mainly absorbed by the matrix and possibly also partially by the induction layer. Depending on where the induction layer is arranged, the coating can be applied to the matrix, to the induction layer or to both elements. The coating can consist of different materials that have the properties described. The coating can, for example, comprise resins such as phenol, melamine or mixed resins. In addition, the coating can include various plastics, such as polypropylene PP. Composite materials such as wood-plastic composites WPC, which are composed of wood and plastic components, are also conceivable. Metallic materials such as iron-based or aluminum-based materials can also be used as a coating. Finally, different types of coatings, for example based on lacquer, can also be used, which can also have conductive properties due to added particles or improved stability due to carbon components.

It is advantageously provided that the formwork skin comprises at least one thermally conductive area which is connected to the matrix. In this embodiment, the induction formwork element comprises a heat-conducting area which is intended to efficiently conduct heat in the formwork facing. The heat conduction area has a significantly higher thermal conductivity than the formlining matrix. During operation of the induction layer, the thermal conduction area is used to heat the formwork skin and to transfer the heat generated in the induction layer by eddy currents. The thermally conductive area can be provided separately from the induction layer and thermally coupled to it. Alternatively, the thermally conductive area can form a common, multifunctional area with the induction layer. On the one hand, such a multifunctional area generates the heat by an introduced electromagnetic alternating field generates eddy currents in it, which in turn heat up the formlining through current heating. On the other hand, the multifunctional area conducts the heat within the formlining and distributes it favorably over the entire surface of the formlining, viewed from above. The thermally conductive area can be shaped differently and arranged in different ways in the formwork skin. Various embodiments of the thermally conductive area are described below.

In one embodiment, it is provided that the matrix and the thermally conductive area are designed as flat layers, with the thermally conductive area extending at least over a partial area of the matrix in a top view of the formlining and the thermally conductive area being arranged inside the matrix or outside and directly adjacent to the matrix is. In this embodiment, the thermally conductive area is designed as a regularly shaped, flat layer. Such a regular, flat layer can be formed by a metal sheet, for example. Alternatively, such a layer can also be provided by a powder coating with a thermally highly conductive material or by similar types of coating. The matrix is preferably formed by a plastic or a wood-based material and is therefore not metallic. Therefore, the thermal conductivity of the matrix is low. The heat conducting area, designed as a flat layer, advantageously consists of a metal material, since metals have good thermal conductivity, which is significantly higher than the thermal conductivity of the preferred materials for the matrix. In the best case, the thermal conduction area extends over the entire surface of the formlining when viewed from above. In practice, such a full-surface extension can usually not be realized. Therefore, the thermally conductive area extends at least over a partial area of the matrix, preferably over an area that is larger than half of the total area of the formlining in plan view. The thermally conductive area can be surrounded by the matrix and arranged inside it. Alternatively, the thermally conductive area can also be arranged adjacent to the matrix.

In an alternative embodiment, it is provided that several thermally conductive areas are provided, which are arranged stochastically distributed within the matrix. In this embodiment, several thermally conductive areas are provided, which are stochastically distributed within the matrix. In this context, stochastic is to be understood as meaning that the multiple heat-conducting regions are arranged in the matrix in a quasi-random manner. Such a random arrangement of the thermally conductive areas in the matrix can be achieved, for example, by mixing several thermally conductive areas with the matrix to produce the formwork skin and then curing the matrix. This creates a matrix that contains several thermally conductive areas randomly distributed in its interior. Of course, several thermally conductive areas can also be arranged in a regular pattern inside the matrix. An arrangement of several thermally conductive areas inside the matrix has the advantage that, in addition to good thermal conductivity of the formlining parallel to the carrier side or to the workpiece side, there is also good thermal conductivity in the thickness direction, i.e. from the carrier side to the workpiece side or vice versa.

In an advantageous embodiment, it is provided that the several thermally conductive areas are formed by three-dimensional objects that have an irregular shape, with the thermal conductivity of these three-dimensional objects being greater than the thermal conductivity of the matrix. In this embodiment, the plurality of thermally conductive areas are, at least in part, irregularly shaped. An irregular shape is to be understood here as meaning that the shape or shape of the individual heat-conducting areas differs from one another. An example of such thermally conductive areas with an irregular shape are metal shavings, which are produced, for example, as a waste product in the production of metal parts by milling, drilling or turning. In addition, thermally conductive areas with an irregular shape can also be formed, for example, by sheet metal sections with an irregular size and shape, such as are produced as a waste product in sheet metal processing. In general, there are no particular limits to the shape and size of the heat-conducting area. The only essential thing is that the thermal conductivity of the thermally conductive areas is significantly higher than the thermal conductivity of the matrix.

Cleverly, it is provided that the multiple thermal conduction areas are formed by three-dimensional objects, the longest dimension of these three-dimensional objects being up to 20 mm, preferably up to 10 mm, particularly preferably up to 2 mm. In this embodiment, several thermally conductive areas extend in all three spatial directions. The longest dimension of the thermally conductive areas is to be understood as meaning the dimension that has the greatest absolute value of all dimensions. The longest dimension of the three-dimensional objects is favorably selected in such a way that it is of the order of magnitude of the thickness of the formwork skin. Here, thermally conductive areas with smaller dimensions are usually easier to process than thermally conductive areas with larger dimensions. In a case where the matrix is made of plastic and the heat conducting area is formed by mixing in the matrix before curing tion are introduced, the longest dimensions of the thermal conduction area of 1 to 2 mm have proven to be favorable, since these dimensions can be processed particularly well in plastics processing.

It is advantageously provided that several thermally conductive areas are provided within the matrix and the matrix and the thermally conductive areas form a common layer of the induction formwork element, with the volume proportion of the thermally conductive areas in this common layer being up to 75%, preferably up to 50%, particularly preferably up to is 35%. In this embodiment, several thermally conductive areas and the matrix form a common layer of the formwork skin. The thermally conductive areas can be distributed regularly or irregularly in the matrix. The proportion by volume of the thermally conductive areas in this common layer is at least 35%. The thermally conductive areas can also be referred to as the filling material of the matrix. The matrix thus has a degree of filling of at least 35%. However, in order to ensure optimum thermal conductivity of the formwork facing, the proportion by volume of the thermally conductive areas is preferably at least 50%.

In one embodiment it is provided that the thermally conductive areas are formed by chips made of a thermally highly conductive material, in particular a metal material. In this embodiment, the multiple heat conducting portions are formed by chips. As described above, chips are produced as waste material in many processes, for example in metal processing. Since the geometric requirements for the thermally conductive areas are low, such waste products can be used to fill the matrix to improve the thermal conductivity of the formlining. It is also possible to use chips from different metal materials as heat conducting areas. This has the advantage that even non-sorted waste from metal processing can be reused as heat-conducting areas in a formwork skin in a cost-effective and environmentally friendly manner. As an alternative to chips, powders with high thermal conductivity, for example metal powders produced by painting metal waste, can also be used as heat-conducting areas.

Furthermore, it is provided that the thermally conductive area consists of an iron-based material or an aluminum-based material and/or the matrix consists of a plastic, in particular polypropylene, or a material which is at least partially made of a renewable raw material, in particular wood. Suitable materials for the thermally conductive area or the multiple thermally conductive areas are metal materials. If the heat conducting area is to take on the function of an induction layer at the same time, care must be taken to use a ferromagnetic metal material, for example an iron-based material. If the thermal conduction area is provided in addition to an induction layer, only the thermal conductivity of the material is in the foreground, which means that aluminum-based materials, brass, copper or bronze materials can also be used, for example. Suitable materials for the matrix are plastics such as polypropylene. Alternatively, however, the matrix can be formed from a material which at least partially contains a renewable raw material such as wood, bamboo, hemp or wool.

In an advantageous embodiment, it is provided that several thermally conductive areas are provided, which consist of a metallic material and the thermally conductive areas are distributed within a matrix made of plastic, with the thermally conductive areas and the matrix forming a common layer and this common layer being produced by a plastics processing method is, in which the heat conducting areas are used as filling material for the matrix. In this embodiment, a common layer of matrix and multiple thermally conductive areas is produced in a common manufacturing step. The matrix is formed from a plastic, the heat conducting areas from a metallic material, for example metal chips. The thermally conductive areas form the filling material for the matrix. The plastic granules and the thermally conductive areas are first mixed. After mixing, the common layer is shaped, for example by injection molding or casting. To do this, the mixture is heated until the plastic granulate liquefies and can be brought into the desired shape in this liquid state. The shaped mixture is then cooled so that the matrix solidifies, with the thermally conductive areas being firmly enclosed in the interior or in the edge area of the matrix. This manufacturing process creates a common layer in which the thermally conductive areas are distributed randomly or stochastically in the matrix and are held in a fixed position relative to one another by the matrix. Alternatively, several thermally conductive areas can also be placed in a mold and then liquid plastic matrix material can be fed in for overmolding or casting around these inserted thermally conductive areas. The advantage of such a processing method or manufacturing method is that a large number of acoustic skins can be produced inexpensively and with reproducible quality. In addition, the adhesion between the matrix and the heat conduction very well, which gives the formlining a high level of strength.

In an alternative embodiment, it is provided that several thermally conductive areas are provided, which consist of a metallic material and the thermally conductive areas are arranged within a matrix, which has chips made of a renewable raw material, in particular wood, and the thermally conductive areas and the matrix form a common layer, this common layer being produced by mixing the thermally conductive areas with the chips of the matrix formed from a renewable raw material and an adhesive, and then curing the common layer. In this embodiment, too, several thermally conductive areas and the matrix form a common layer. However, the matrix here includes chips from a renewable raw material, for example from wood. These shavings of the matrix are first mixed with the several thermally conductive areas, with an adhesive also being mixed in. The mixture is then cured. This hardening can take place, for example, by pressing and/or heating. A firm, common layer of heat-conducting areas and matrix is thus obtained, which has a structure similar to that of a pressboard. The advantage of this embodiment is that it consists largely of renewable raw materials and is therefore environmentally friendly. Advantageously, heat conducting areas are used in this embodiment, which consist of metal chips. Alternatively, in this embodiment, chips made from metallic alloys specially produced for this application can also be used. Such special alloys can be designed to have an optimal mix of thermal conductivity, ferromagnetic properties and electrical conductivity.

It is cleverly provided that the formwork skin has a coating which is arranged on the side facing away from the carrier element adjacent to the matrix and/or the heat-conducting area, with the coating forming the workpiece side. A coating is also provided in this embodiment, which forms the side of the workpiece that faces the concrete part to be produced. The particular task of this coating is to prevent or at least reduce adhesion of the concrete material to the formlining. In this case, the coating is arranged on the matrix and/or on the heat-conducting area. Favorably, the coating is arranged directly on the thermally conductive area, since with such a structure the thermally conductive area is positioned very close to the concrete part to be erected.

Furthermore, it is advantageously provided that the thermally conductive area and the induction layer are formed by different elements. In this embodiment, the thermally conductive area and the induction layer of the formwork skin form different areas and are provided as separate elements. There is therefore a functional separation between the generation of heat in the formlining, which takes place in the induction layer, and the transmission of heat, which takes place through the heat-conducting area. The induction layer and the heat conduction area are thermally coupled with one another in order to achieve good heat distribution in the formlining.

In an advantageous embodiment it is provided that the heat conducting area is arranged closer to the side of the workpiece than the induction layer. In this embodiment, the thermally conductive area is arranged closer to the concrete part to be erected than the induction layer. As a result, the heat distributed by the heat conduction area is made available very close to the concrete part. The induction layer, in turn, is arranged closer to the carrier side of the formlining, which makes it easier to introduce an alternating magnetic field over a short distance. This ensures good efficiency when heating the induction layer by induction. The heat transfer takes place from the induction layer, where the heat is generated, to the heat-conducting area and from the heat-conducting area to the concrete part.

In an alternative embodiment it is provided that the heat conducting area and the induction layer are identical. In this embodiment, the thermally conductive area to the induction layer form a common area or element. This means that this common area takes care of both the generation of heat by induction and the distribution of heat in the formlining. This embodiment is advantageous because fewer partial areas of the formwork skin have to be produced. In a simple embodiment, the formwork skin is formed only by the matrix and the common element, which includes the thermally conductive area and the induction layer. In this way, a simply constructed and lightweight formlining with a high level of functionality can be made available.

Furthermore, it is provided that several thermally conductive areas are provided, which simultaneously form several induction layers, with at least some of the thermally conductive areas having maximum dimensions of at least 2 mm, preferably at least 5 mm, particularly preferably at least 10 mm. In this embodiment there is also a functional combination of heat generation and heat transmission. Several heat conducting areas are introduced into a matrix, which at the same time act as induction layers. In order to efficiently design current heating, which is generated by induced eddy currents in the induction layers, the induction layers/thermally conductive areas have larger dimensions than is the case with purely thermally conductive areas. The larger dimensions are required in order to give the eddy currents the opportunity to flow over a greater distance and to heat up the induction layers as a result of the current flow. The maximum dimensions of the common thermally conductive areas/induction layers are therefore advantageously in the range of several millimeters. It is also possible to provide only part of the common thermally conductive areas/induction layers with larger dimensions and to mix in another part with smaller dimensions. This other part then acts primarily to conduct heat and less to generate heat by induction.

The object of the invention is also achieved by a heating system for a concrete part produced by casting, comprising at least one induction formwork element according to one of the embodiments described above and at least one induction heating device, which generates an alternating electromagnetic field, the induction heating device being attachable to the carrier side of the formwork skin and the The alternating electromagnetic field generated by the induction heating device generates eddy currents in the induction layer of the formlining, which heat up the induction layer.

A heating system according to the invention comprises at least one induction formwork element. For the production of larger concrete parts, however, the heating system can also include several induction formwork elements. In addition, an induction heating device is provided in the heating system according to the invention, which is used to induce electrical currents in the induction layer of the induction formwork element. These electrical currents then flow in the induction layer and heat it up according to the principle of current heating. The induction heater generates an electromagnetic alternating field that changes over time. Eddy currents are induced or generated in the induction layer by this time-varying electromagnetic alternating field. Induction heaters are known in principle and are used in different areas of technology. For example, such induction heaters can be used for local heating of machine components in order to loosen tight connections or the like. In the heating system according to the invention, the induction heating device can be attached to the carrier side of the formwork skin. The induction heating device can preferably be attached to the carrier element of the induction formwork element and detached from it again. The connection between the two elements is designed in such a way that it can be made and released quickly and easily. Provision is made for the induction heating device to be connected to the induction formwork element only in the event that the formwork skin has to be heated. The induction heating device can thus be detached from the formwork skin, as a result of which the induction heating device does not impede the handling of the induction formwork element during assembly and dismantling of the formwork. The advantage of the heating system according to the invention is that the induction formwork element hardly differs from a normal formwork element and can therefore be transported, assembled and dismantled in a simple, familiar manner. The induction formwork element can also be used for formwork where no heating of the formwork is required. In a case in which the formwork or the concrete part to be erected has to be heated, the formwork is first set up in a conventional manner. The induction heater is then attached to the induction formwork element and can be used to preheat the formlining before pouring the concrete part. This is particularly useful at low ambient temperatures. The concrete part to be erected is then poured. The induction heater can remain connected to the induction formwork element and heat the formwork. The heating of the formwork is continued until the concrete part has hardened sufficiently. In a case where a formwork comprises several induction formwork elements, a single induction heating device can also be moved at time intervals from one induction formwork element to the other, as a result of which the individual induction formwork elements can be heated at intervals with a single induction heating device. This relocatability of the induction heating device enables cost savings compared to a solution in which a separate heating device is permanently installed on each heatable formwork element. In addition, the induction heater is compact in structure and can be attached to and detached from the induction form member by a single person. Machines such as a crane are not required to attach the induction heater. A heating system according to the invention can therefore be operated in a simple manner by one person. If the temperatures are very low or if the curing time of the concrete part is very short, it is also possible to provide several induction heating devices and connect them to a single induction formwork element. In this way, the heating system according to the invention can be easily and flexibly adapted to different requirements with regard to the required heating output.

In one embodiment of the heating system, it is provided that the induction heating device is detachably attached to the support element, with a partial area of the induction heating device being arranged in direct contact with the formwork skin or at a small distance, which is in particular smaller than the thickness of the support element, from the formwork skin. In this embodiment, the induction heating device is detachably attached to the carrier element of the induction formwork element. This support element can be assembled from metal profiles or tubes, and the support element can be constructed from these elements in the form of a lattice. For example, the carrier element, seen in a plan view from the direction of the formwork skin, can have an outer peripheral frame and have struts oriented at right angles to one another in its interior, which form a lattice. In the recesses of this grid, direct access to the formlining is possible, which is attached to the support element. These recesses in the grid are an ideal place to attach the induction heater as the induction heater can be brought into direct contact with the formlining here. The induction heater generates an alternating electromagnetic field, the intensity of which decreases with the square of the distance from the point of generation. It is therefore preferable to attach the induction heating device, if possible, directly adjacent to the formlining or the induction layer of the formlining. In this way, maximum energy transfer between the induction heater and the formwork is possible. In practice, it is sometimes not possible to put the induction heater directly on or touch it. In this case, however, the induction heater should be positioned as close as possible to the formlining. It is therefore intended that the induction heating device be arranged at a distance from the formwork skin which is less than the thickness of the carrier element. Eddy currents are of course still generated in the induction layer for heating the formwork when the induction heating device is arranged at a greater distance from the formwork. The induction heater can be attached to the carrier element using different connection mechanisms: in a simple embodiment, hooks can be provided on the carrier element, on which the induction heater is hung. Alternatively, bolts or screw connections can be used. Furthermore, it is possible to use other positive connection types, such as a bayonet lock, for the connection. Attachment via magnetic connectors is also conceivable. Finally, in an alternative embodiment, it is also possible not to fasten the induction heating device to the induction formwork element, but to position the induction heating device in a self-supporting manner, for example on a tripod. This last embodiment has the advantage that no interfaces for attaching the induction heating device have to be provided on the carrier element.

1. A) Positionierung zumindest eines Induktionsschalungselementes nach einer der zuvor beschriebenen Ausführungsformen,
2. B) Anbringung eines Induktionsheizgerät an dem Induktionsschalungselement, so das ein vom Induktionsheizgerät erzeugtes elektromagnetisches Wechselfeld Wirbelströme in der Induktionslage erzeugen kann,
3. C) Aktivierung des Induktionsheizgerätes, wodurch das vom Heizgerät erzeugte elektromagnetische Wechselfeld Wirbelströme in der Induktionslage erzeugt und diese Wirbelströme die Induktionslage und damit die Schalhaut sowie das hergestellte Betonteil erwärmen.

The object of the invention is further achieved by a method for heating a concrete part produced by casting using a heating system according to one of the preceding embodiments, comprising the steps

1. A) positioning of at least one induction formwork element according to one of the previously described embodiments,
2. B) Attaching an induction heater to the induction formwork element so that an alternating electromagnetic field generated by the induction heater can generate eddy currents in the induction layer,
3. C) Activation of the induction heater, as a result of which the electromagnetic alternating field generated by the heater generates eddy currents in the induction layer and these eddy currents heat the induction layer and thus the formwork skin and the concrete part produced.

The method according to the invention is used for heating a concrete part or part of a building. In particular, a heating system according to one of the previously described embodiments is used for the method. The process according to the invention is preferably carried out in the specified order of process steps A) to C). In a first method step A), a formwork is set up, with at least one induction formwork element being positioned. Additional induction formwork elements can also be positioned and connected to one another. In addition, it is also possible to connect and position conventional formwork elements with at least one induction formwork element. The first process step A) is completed as soon as the desired formwork for creating the concrete part is complete.

In a second method step B), at least one induction heating device is attached to the induction formwork element or is arranged in some other way in the vicinity of the induction formwork element. The induction heating device is positioned as close as possible to the formwork skin of the induction formwork element. When attached, the induction heater can then generate an electromagnetic alternating field, which affects the induction layer of the formlining and generates eddy currents there.

In a third method step C), the induction heater is activated and then generates an electromagnetic change in the activated state selfeld, which penetrates into the induction layer of the formlining. The temporal change in the electromagnetic alternating field generates eddy currents in the ferromagnetic induction layer of the formlining, which in turn warms up or heats up the induction layer through current heating. The heat generated in the induction layer is then passed on in the formwork skin, preferably through at least one heat-conducting area. The beginning of the third method step C) can be started before pouring the concrete material for producing the concrete part, in order to preheat the induction formwork element. Alternatively, method step C) can only be started after the concrete material has been poured into the formwork. The operation of the induction heater and thus the heating of the induction formwork element is continued until the concrete part has achieved the desired curing. It is also possible to heat the induction formwork element at intervals, ie to temporarily interrupt the operation of the induction heating device. In addition, the induction heating device can have a control circuit which determines the temperature of the formwork skin via a sensor and regulates the heating output based on a target/actual comparison of the formwork skin temperature. After the concrete part has hardened, the method according to the invention for dismantling the formwork is carried out in reverse order.

The method according to the invention has the advantage that it can be carried out quickly and easily. A complex attachment and activation of a conventional heating device is not necessary with the method according to the invention. In method step A), the induction formwork element can be handled and set up like a conventional formwork element. There are no hindrances and no additional expense for the fact that the induction formwork element is a heatable formwork element. The attachment and activation of the induction heating device in method steps B) and C) is simple and can be carried out by one person alone due to the small dimensions and the low weight of the induction heating device. Thus, the induction heater is ready for use in a short time. In addition, the concrete part to be erected is heated very energy-efficiently by the method according to the invention, since the heat for heating the concrete part is generated in the immediate vicinity of the concrete part. The heat losses to the environment that occur in the method according to the invention are therefore significantly lower than in conventional methods for heating a formwork.

Also disclosed is a formwork element with improved thermal conductivity for creating a concrete part, comprising at least one carrier element which carries the other elements of the formwork element and absorbs and supports the mechanical load acting on the formwork element and at least one formwork skin which has a matrix and a Matrix-connected thermal conduction area includes,
wherein the formwork skin can be connected to the support element and can be detached from it, the formwork skin having a support side which, when connected to the support element, faces the latter and the formwork skin having a workpiece side which is arranged on the side of the formwork skin opposite the support side and the workpiece side comes into contact with the concrete part to be created in the application.

In contrast to the induction formwork element according to the invention, this disclosed formwork element has no induction layer. The disclosed formwork element is therefore not actively heatable. However, the disclosed formwork element has a thermally conductive area, as a result of which the thermal conductivity of the formwork element is significantly improved compared to conventional formwork elements. This improved thermal conductivity means that the heat generated during the hardening of the concrete part can be dissipated quickly and efficiently to the environment. This is particularly advantageous at very high ambient temperatures. In addition, the disclosed formwork element can be advantageously used in connection with conventional heating systems for formwork. Due to the improved thermal conductivity of the formwork skin, which is based on the provision of the thermal conduction area, the formwork skin has a lower thermal resistance than conventional formwork skins, as a result of which the energy efficiency during heating using conventional heating devices can be significantly improved. Thus, even a formwork element without an induction layer, which is provided with a thermally conductive area, is a solution, formwork or a concrete part to be erected that can be heated easily and in an energy-efficient manner.

Features, effects and advantages that are disclosed in connection with the induction formwork element and the heating system are also deemed to be disclosed in connection with the method. The same applies in reverse, features, effects and advantages which are disclosed in connection with the method also apply in connection with the induction formwork element and the heating system as disclosed.

• 1 eine schematische, perspektivische Ansicht einer Ausführungsform eines erfindungsgemäßen Heizsystems,
• 2 eine Draufsicht auf eine erste Ausführungsform einer Schalhaut eines erfindungsgemäßen Induktionsschalungselementes,
• 3 eine geschnittene Seitenansicht einer zweiten Ausführungsform einer Schalhaut eines Schalungselementes,
• 4 eine geschnittene Seitenansicht einer dritten Ausführungsform einer Schalhaut eines Schalungselementes,
• 5 eine geschnittene Seitenansicht einer vierten Ausführungsform einer Schalhaut eines erfindungsgemäßen Induktionsschalungselementes,
• 6 eine geschnittene Seitenansicht einer fünften Ausführungsform einer Schalhaut eines erfindungsgemäßen Induktionsschalungselementes,
• 7 eine geschnittene Seitenansicht einer sechsten Ausführungsform einer Schalhaut eines erfindungsgemäßen Induktionsschalungselementes,
• 8 eine geschnittene Seitenansicht einer siebten Ausführungsform einer Schalhaut eines erfindungsgemäßen Induktionsschalungselementes und
• 9 eine geschnittene Seitenansicht einer Ausführungsform eines erfindungsgemäßen Heizsystems.

In the figures, embodiments of the invention are shown schematically. show it

• 1 a schematic, perspective view of an embodiment of a heating system according to the invention,
• 2 a top view of a first embodiment of a formwork skin of an induction formwork element according to the invention,
• 3 a sectional side view of a second embodiment of a formwork skin of a formwork element,
• 4 a sectional side view of a third embodiment of a formwork skin of a formwork element,
• 5 a sectional side view of a fourth embodiment of a formwork skin of an induction formwork element according to the invention,
• 6 a sectional side view of a fifth embodiment of a formwork skin of an induction formwork element according to the invention,
• 7 a sectional side view of a sixth embodiment of a formwork skin of an induction formwork element according to the invention,
• 8th a sectional side view of a seventh embodiment of a formwork skin of an induction formwork element according to the invention and
• 9 a sectional side view of an embodiment of a heating system according to the invention.

The same elements are provided with the same reference symbols in the figures. In general, the properties of an element that are described for one figure also apply to the other figures. Directional information such as above or below relates to the figure described and is to be transferred to other figures accordingly.

1 shows a schematic, perspective view of an embodiment of a heating system 100 according to the invention. The heating system 100 comprises, shown on the left, an induction formwork element 2 and, shown on the right side, an induction heater 3. In the state shown, the induction heater 3 is not with the induction formwork element 2 connected but shown at a certain distance from the induction formwork element 2. The induction formwork element 2 comprises a plurality of layers in the thickness direction. The thickness direction is to be understood as meaning a direction that is oriented at right angles to the workpiece side 12b, a surface of the formwork skin 12, that faces the workpiece. In 1 the thickness direction of the induction formwork element 2 runs in the horizontal direction from right to left or vice versa.

The supporting structure of the induction formwork element 2 is formed by the support element 11 shown on the right in the illustration. The carrier element 11 is designed here as a frame which carries the other elements of the induction formwork element 2, in particular the formwork skin 12, and absorbs and supports the mechanical load which is exerted by the workpiece on the formwork skin 12 when the induction formwork element 2 is used. The carrier element 11 is composed of steel tubes with a rectangular cross-section and comprises an outer peripheral frame 111 and a lattice structure 112 within this frame 111. Recesses 113 are provided between the elements of the carrier element 11, which form the frame 111 and the lattice structure 112. The weight of the carrier element of FIG. 11 is reduced by these recesses 113 . These recesses 113 are also a suitable place for attaching the induction heater 3. The support element 11 can also be different from that in 1 be designed embodiment shown. In principle, different types of carrier elements 11 are suitable as a component of an induction formwork element 2. The carrier element 11 can, for example, also consist of other materials, such as an aluminum-based material, plastic or wood. However, the carrier element 11 should preferably have at least one recess 113 in order to be able to attach an induction heating device 3 in the immediate vicinity of the formwork skin 12 .

On the left in 1 is the formwork skin 12 of the induction formwork element 2. The formwork skin 12 is in direct contact with a concrete part when it is erected or manufactured. A concrete part is in 1 not shown. A concrete part to be erected would be to the left of the coating 123 of the formwork skin 12 . The formwork skin 12 is detachably connected to the carrier element 11 . A connection between the formwork skin 12 and the carrier element 11 can be produced, for example, via a nail connection, a screw connection or a rivet connection. The connection between the formwork skin 12 and the carrier element 11 is therefore designed to be detachable, since the formwork skin 12 and in particular its coating 123 wear out with repeated use and therefore have to be replaced from time to time. The carrier element 11, on the other hand, is hardly subject to wear and tear and can be used for a much longer period of time. Here, the formwork skin 12 comprises a matrix 121 adjoining the carrier element 11. A multiplicity of thermally conductive regions 122 are arranged in this matrix. The thermally conductive areas 122 are formed here by irregularly shaped, three-dimensional objects. The thermally conductive areas 122 here consist of metal chips with good thermal conductivity. The thermal conductivity rich 122 are arranged stochastically, ie randomly, distributed in the matrix 121 . The heat conducting areas 122 have a significantly higher thermal conductivity than the material from which the matrix 121 is formed. The thermal conductivity of the formwork skin 12 is therefore significantly improved by the arrangement of the thermally conductive regions 122 . As a result, the heat transport to the workpiece side 12b, which is the surface of the formwork skin 12 oriented to the left in the illustration, is significantly improved. At the same time, the heat transport from the workpiece side 12b to the carrier side 12a is improved. This improved heat transport or this improved thermal conductivity can be used advantageously for heating the concrete part to be erected and also for cooling the concrete part to be erected. The improved thermal conductivity of the formwork skin 12 compared to the prior art is advantageous in both cases. In order to achieve good thermal conductivity in the common layer made up of matrix 121 and thermally conductive region 122, the proportion by volume of the thermally conductive regions 122 in the common layer is at least 50%. In the embodiment shown, the matrix 121 consists of a plastic and the thermally conductive areas 122 consist of metal materials. In the embodiment shown, the thermally conductive areas 122 can also consist of different metal materials. The common layer, which includes the matrix 121 and the thermally conductive area 122, was produced here in a common method step. The thermally conductive areas 122 were first mixed with the plastic material of the matrix 121 before the layer was formed. The mixture was then heated so that the material of the matrix 121 liquefies. In the liquefied state, the layer was then shaped, for example by pouring into a mould. The layer was finally cooled, as a result of which the thermally conductive areas 122 were firmly enclosed by the material of the matrix 121 and with good adhesion. In the embodiment shown, a coating 123 is applied to the common layer of matrix 121 and thermally conductive areas 122 on the left-hand side. This coating 123 serves to shape the workpiece side 12b of the formwork skin 12 in such a way that the concrete material of the concrete part to be erected does not adhere to the workpiece side 12b. The coating 123 can consist of various suitable materials which prevent or at least reduce the adhesion of concrete material. However, a coating 123 is not absolutely necessary.

The formwork skin 12 also includes at least one induction layer 124. The induction layer 124 is here continuous or self-contained and is formed by an iron sheet which is inserted or cast into the matrix 121 on the carrier side 12a. Since the induction layer 124 consists of a ferromagnetic material, an alternating electromagnetic field can induce eddy currents in the induction layer 124 . These eddy currents then flow inside the induction layer 124 and heat it up by current heating. In the illustrated embodiment, the induction layer 124 is smaller than the total surface of the formwork 12 in a plan view of the formwork 12, for example from the workpiece side 12b. The induction layer 124 is also thinner here than the total thickness of the common layer of matrix 121 and heat-conducting areas 122. Since the induction layer 124 forms part of the carrier side 12a of the formwork skin 12 in the illustrated embodiment, the induction layer 124 can be reached through the recesses 113 of the carrier element 11. This is particularly advantageous for attaching the induction heating device 3. In the illustrated embodiment, the induction heating device 3 can be attached to the induction formwork element 2 in such a way that at least a partial area of the induction heating device 3 touches the induction layer 124 directly and immediately. This results in an optimal transfer of energy between the induction heater 3 and the induction layer 124. The induction heater 3 transfers energy in the form of an alternating electromagnetic field. The intensity of this alternating electromagnetic field decreases with the square of the distance from the place where the alternating field was generated. For this reason, there is an optimal energy transfer in the case when the induction heating device 3 and the induction layer are in direct contact. Alternatively, energy transmission over a small distance between the two elements is also favorable. An induction formwork element 2 absolutely requires the provision of at least one induction layer 124. In contrast, the provision of one or more heat-conducting areas 122 is not absolutely necessary for an induction formwork element 2. Furthermore, a formwork element is disclosed which does not have an induction layer 124 but is provided with at least one heat-conducting area 122 instead. Such a formwork element passively has a significantly improved thermal conductivity, but cannot be actively heated.

at 1 This is a schematic representation, so the layer thicknesses shown are not true to scale. In particular, the coating 123 and the induction layer 124 can in reality have a significantly smaller layer thickness compared to the overall thickness of the formwork skin 12 .

2 shows a plan view of a first embodiment of a formwork skin 12 of an induction formwork element 2 according to the invention 2 is the formlining alone, i.e. without it the other components of the induction formwork element 2 are shown in a plan view viewed from the workpiece side 12b. A total of three different induction layers 124 can be seen in dashed lines. The induction layer 124 arranged on the right-hand edge corresponds to that in 1 Induction layer 124 shown. Two induction layers 124 are shown on the left-hand side, one of these induction layers 124 being significantly larger than the induction layer 124 shown on the right. The second induction layer 124 shown on the left is smaller or has a smaller area than the induction layer 124 shown on the right. In the 2 The illustrated embodiment of a formwork skin 12 thus has three induction layers 124, which are all designed to be continuous or self-contained. In this case, the induction layers 124 are arranged partially next to one another and partially one above the other. An induction formwork element 2 according to the invention can comprise a formwork skin 12 with differently arranged induction layers 124, which can also have a size other than that shown. In the 2 The illustrated embodiment includes induction layers 124, which are designed as thin iron sheets or thin iron foils. Alternatively, it is also possible for the induction layers 124 not to be closed in themselves, but rather to have recesses at least in some areas or be in the form of a grid. By providing several induction layers 124, which extend over a larger area of the surface of the formwork skin 12 in plan view, an induction heating device 3 can be attached at different points on the induction formwork element 2, with the induction heating device 3 being able to be positioned very close to an induction layer 124 in each case . In addition, a number of induction heating devices 3 can be arranged at different points in relation to the formwork skin 12 and can be used to heat the formwork skin together. Ideally, an induction layer 124 can also extend over the entire surface of the formwork skin 12 .

The following 3 until 8th 12 show different embodiments of a formwork skin 12 in sectional side views. These embodiments differ from one another in the layer structure and/or in the overall thickness of the formwork skin 12.

3 shows a sectional side view of a second embodiment of a formwork skin 12 of a formwork element. This embodiment of a formwork skin 12 comprises only one matrix 121 and a plurality of thermally conductive areas 122 distributed stochastically in the matrix. A formwork skin of this type has improved thermal conductivity compared to the prior art and is very simple in construction.

4 shows a sectional side view of a third embodiment of a formwork skin 12 of a formwork element. In the 4 The embodiment shown corresponds to that on the right-hand side in 3 illustrated embodiment of a formwork panel 12. In addition, the embodiment in 4 a coating 123 which is intended to reduce or prevent adhesion of the concrete material to the workpiece side 12b. This embodiment also has improved thermal conductivity, but is like the embodiment in 3 not actively heated. A heating of the embodiments in 3 and 4 is, however, possible passively, for example by attaching a heating mat to the support side 12a of the formlining 12.

5 shows a sectional side view of a fourth embodiment of a formwork skin 12 of an induction formwork element 2 according to the invention. This thermally conductive area 122 is formed by a ferromagnetic metal foil or a ferromagnetic metal sheet, which extends over the entire surface of the formwork skin 12 . Good thermal conductivity is thus provided along the surface of the formwork skin 12 . Due to the fact that the thermally conductive area 122 is formed from a ferromagnetic material, the thermally conductive area 122 simultaneously serves as an induction layer 124 in which eddy currents can be induced. The embodiment has a coating 123 on the left-hand side. The element that forms the thermally conductive area 122 and at the same time the induction layer 124 is arranged directly below the coating 123 and is therefore in the immediate vicinity of the concrete part. In this embodiment, there is particularly good energy efficiency when heating the concrete part. The heat is generated in the immediate vicinity of the concrete part, directly below the coating 123 and is effectively distributed there over the entire surface of the formwork skin 12 .

6 shows a sectional side view of a fifth embodiment of a formwork skin 12 of an induction formwork element 2 according to the invention. However, a corresponding layer, which forms both elements, is here arranged on the carrier side 12a. This embodiment has a matrix 121 on the workpiece side 12b, which encloses the common layer of heat-conducting region 122 and induction layer 124 on three sides. The one shown The embodiment does not include a coating 123. In the illustrated embodiment, the matrix 121 consists of a material which itself prevents adhesion of the concrete material, as a result of which the coating 123 can be omitted. In the embodiment shown, the common layer made up of induction layer 124 and heat-conducting region 122 can be provided with an increased layer thickness in comparison to the previously described embodiments. In this case, although the weight of the formwork skin 12 increases, its mechanical strength also increases significantly. Such a formwork skin 12 is suitable for connection to a less stable and solid support element 11, since the formwork skin is able here to absorb greater mechanical loads even without the support of the support element 11. In this way, even a self-supporting formwork skin 12 can be realized.

7 shows a sectional side view of a sixth embodiment of a formwork skin 12 of an induction formwork element 2 according to the invention. The embodiment shown here essentially corresponds to the embodiment of the formwork skin 12 in FIG 1 . This embodiment includes a matrix 121 in which a plurality of thermally conductive regions 122 are stochastically distributed. In addition, the embodiment includes a coating 123 on the workpiece side 12b and a continuous induction layer 124, which forms part of the carrier side 12a. In this embodiment, the heat is generated in the induction layer 124 arranged on the carrier side 12a. The generated heat is transported through the heat conducting areas 122 in the thickness direction through the formwork skin 12 and transported through the coating 123 to the concrete part.

8th shows a sectional side view of a seventh embodiment of a formwork skin 12 of an induction formwork element 2 according to the invention. This embodiment is very similar to that in FIG 3 illustrated embodiment. in the in 8th In the illustrated embodiment, the plurality of thermally conductive areas 122, which are stochastically arranged in the matrix 121, form a plurality of induction layers 124 at the same time also act as induction layers 124. So that sufficient heating can take place through current heating, at least the ferromagnetic induction layers 124 have larger maximum dimensions than the thermally conductive areas 122 in the in 3 illustrated embodiment. in the in 8th illustrated embodiment, the material of the matrix 121 is chosen so that it prevents adhesion of the concrete material, whereby no coating 123 is required. What is particularly advantageous about this embodiment is that it has a very simple structure and a formwork skin 12 with a small layer thickness can be achieved. As a result, a formwork skin according to this embodiment is lightweight and therefore particularly easy to transport and install, with this embodiment being both inductively heatable and having good thermal conductivity.

The layer structures of the in 3 until 8th The embodiments shown can be freely combined with one another in order to achieve advantageous results.

9 shows a sectional side view of an embodiment of a heating system 100 according to the invention 9 The embodiment of a heating system 100 shown is very similar to that in FIG 1 illustrated embodiment. in the in 9 However, in the illustrated embodiment, the carrier element 11 is designed in such a way that it also partially encloses the formwork skin 12 in its thickness direction. In the sectional view in 9 an induction heating device 3 can be seen, which is connected to the induction formwork element 2 . The induction heating device 3 is connected to the induction formwork element 2 in such a way that the area of the induction heating device 3 from which the alternating electromagnetic field is emitted is positioned in the immediate vicinity of the carrier side 12b of the formwork skin 12 and an induction layer 124 arranged there. For this purpose, the partial area of the induction heating device 3 from which the alternating electromagnetic field is emitted is positioned within a recess 113 in the carrier element 11 . The induction heating device 3 is fastened to the lattice structure 112 of the carrier element 11 adjacent to the recess 113 via a fastening device 31 . In the embodiment shown, the fastening device 31 comprises an angle bracket which is firmly connected to the induction heating device 3 and a plurality of screws which are screwed into the carrier element 11 through the angle bracket. In this way, the induction heating device 3 is detachably connected to the carrier element 11 . However, the fastening device 31 can also be designed differently, for example as a plug connection, bayonet connection or the like.

In 9 it can be seen that the formwork skin 12 is detachably connected to the carrier element 11 by fastening elements 13 . In the illustrated embodiment, these fastening elements 13 are formed by countersunk screws which are screwed from the workpiece side 12b through the formwork skin 12 into the support element 11 and thus fix the formwork skin 12 to the support element 11 . This connection is designed to be detachable, so that the formwork skin 12 can be easily replaced. Alternatively, the connection can also be made by nails or rivets. The advantage of the heating system 100 according to the invention is that the formwork skin 12 is made up of passive, non-sensitive elements which allow fastening elements 13 to be passed through without the functionality of the formwork skin 12 being damaged. Fastening elements 13 can therefore be attached to different points of the formwork skin 12 and penetrate them. The functionality of the thermally conductive areas 122 and the induction layer 124 is retained without restriction.

Reference List

2

induction formwork element

3

induction heater

11

carrier elements

111

frame

112

lattice structure

113

recess

12

formlining

12a

carrier side

12b

workpiece side

121

matrix

122

heat conduction area

123

coating

124

induction layer

13

fastener

31

fastening device

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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

• EP 3259418 B1 [0003]

Claims (17)

Induction formwork element (2) which can be inductively heated to produce a concrete part, comprising - at least one carrier element (11) which carries the other elements of the induction formwork element (2) and absorbs and supports the mechanical load which acts on the induction formwork element (2), - at least one formwork skin (12) which comprises a matrix (121) and at least one induction layer (124), the induction layer (124) consisting of a ferromagnetic material and the induction layer (124) and the matrix (121) being connected to one another, wherein the induction layer (124) is flat and extends over at least 10% of the surface of the formwork skin (12) in a plan view of the formwork skin (12), the formwork skin (12) being connectable to and detachable from the carrier element (11). the formwork skin (12) has a support side (12a) which, when connected to the support element (11), points towards the latter and the formwork skin (12) has a workpiece side (12b) which is on the support side (12a) is arranged on the opposite side of the formwork skin (12) and the workpiece side (12b) comes into contact with the concrete part to be created in the application. Induction formwork element (2) according to claim 1 , characterized in that the induction layer (124) is arranged within the matrix (121). Induction formwork element (2) according to one of the preceding claims, characterized in that the induction layer (124) is designed to be continuous or self-contained in a plan view of the formwork skin (12). Induction formwork element (2) according to one of the preceding claims, characterized in that several induction layers (124) are provided which are arranged next to one another or at least overlapping in some areas in a plan view of the formwork skin (12). Induction formwork element (2) according to one of the preceding claims, characterized in that the formwork skin (12) has a coating (123) which, on the side facing away from the carrier element (11), adjoins the matrix (121) and/or the induction layer (124 ) is arranged, wherein the coating (123) forms the workpiece side (12b). Induction formwork element (2) according to one of the preceding claims, characterized in that the formwork skin (12) comprises at least one heat-conducting area (122) which is connected to the matrix (121). Induction formwork element (2) according to claim 6 , characterized in that the matrix (121) and the thermally conductive area (122) are designed as flat layers, with the thermally conductive area (122) extending at least over a partial area of the matrix (121) in a top view of the formlining (12) and the Heat conduction area (122) is arranged within the matrix (121) or outside and directly adjacent to the matrix (121). Induction formwork element (2) according to claim 6 , characterized in that several thermally conductive areas (122) are provided, which are arranged stochastically distributed within the matrix (121) and/or the formwork skin (12) has a coating (123) which adjoins the side facing away from the carrier element (11). is arranged on the matrix (121) and/or the thermally conductive area (122), the coating (123) forming the workpiece side (12b). Induction formwork element (2) according to one of Claims 6 until 8th , characterized in that several thermally conductive areas (122) are provided within the matrix (121) and the matrix (121) and the thermally conductive areas (122) form a common layer of the induction formwork element (2), the volume proportion of the thermally conductive areas (122) in this common layer is up to 75%, preferably up to 50%, particularly preferably up to 35%. Induction formwork element (2) according to one of Claims 6 until 9 , characterized in that several heat conducting areas (122) are provided, which consist of a metallic material and the heat conducting areas (122) are distributed within a matrix (121) made of plastic, the heat conducting areas (122) and the matrix (121) form a common layer and this common layer is produced by a plastics processing method in which the thermally conductive areas (122) are used as filling material for the matrix (121) and/or multiple thermally conductive areas (122) are provided, which consist of a metallic material and which Thermally conductive areas (122) are arranged within a matrix (121), which has chips from a renewable raw material, in particular wood, and the thermally conductive areas (122) and the matrix (121) form a common layer, this common layer being due to the mixing of the thermally conductive areas (122) with the Ma chips made from a renewable raw material trix (121) and a detention medium, and subsequent curing of the common layer is produced. Induction formwork element (2) according to one of Claims 6 until 10 , characterized in that the thermally conductive area (122) and the induction layer (124) are formed by different elements. Induction formwork element (2) according to claim 11 , characterized in that the heat conducting area (122) is arranged closer to the workpiece side (12b) than the induction layer (124). Induction formwork element (2) according to one of Claims 6 until 10 , characterized in that the thermally conductive area (122) and the induction layer (124) are identical. Induction formwork element (2) according to Claim 13 , characterized in that a plurality of thermally conductive areas (122) are provided, which simultaneously form a plurality of induction layers (124), with at least some of the thermally conductive areas (122) having maximum dimensions of at least 2 mm, preferably at least 5 mm, particularly preferably at least 10 mm . A heating system (100) for a cast concrete member comprising - at least one induction formwork element (2) according to one of the preceding claims, - at least one induction heating device (3) which generates an alternating electromagnetic field, the induction heating device (3) being attachable to the carrier side (12a) of the formwork (12) and the alternating electromagnetic field generated by the induction heating device (3) in the induction layer (124) the formwork skin (12) generates eddy currents which heat the induction layer (124). Heating system (100) after claim 15 , characterized in that the induction heating device (3) is detachably fastened to the carrier element (11), with a partial area of the induction heating device (3) being arranged in direct contact with the formwork skin (12) or at a small distance which, in particular, is smaller than the thickness of the Carrier element (11) is arranged for formwork skin (12). A method of heating a cast concrete member using a heating system (100) according to any preceding claim, comprising the steps of A) Positioning at least one induction formwork element (2) according to one of the preceding claims, B) attachment of an induction heater (3) to the induction formwork element (2) so that an alternating electromagnetic field generated by the induction heater (3) can generate eddy currents in the induction layer (124), C) Activation of the induction heater (3), whereby the electromagnetic alternating field generated by the heater (3) generates eddy currents in the induction layer (124) and these eddy currents heat the induction layer (124) and thus the formwork skin (12) and the concrete part produced.

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